Is it possible to weld a cast iron engine block?

Is it possible to repair a cast-iron engine block yourself, and how to do it correctly, professionals tell you. They have proven in practice that in a garage, having a welding machine and working skills, it is possible to restore the tightness of the metal and its operating parameters. This engine has been in use for many years.

Cast iron tolerates overheating well, has the necessary rigidity, and has a large margin of safety. Two types of cast iron are used: gray is easy to weld, white is high-carbon, forms a loose seam, and requires special welding skills.

How to weld a cast iron engine block

Massive cylinder housings are made from cast iron. This durable material has one significant drawback - it is very fragile.
When struck, cracks form on it or the wall is completely destroyed. Due to small defects, service stations often suggest replacing the engine, although cracks can be effectively eliminated by welding ICE (internal combustion engine) blocks. Is it possible to repair a cast-iron engine block yourself, and how to do it correctly, professionals tell us. They have proven in practice that in a garage, having a welding machine and working skills, it is possible to restore the tightness of the metal and its operating parameters. This engine has been in use for many years.

Properties and weldability of cast iron

Due to the increased carbon content in welds, pores filled with carbon monoxide are formed. Voids reduce the mechanical strength of the cast iron structure, in which cracks appear. The metal is characterized by rapid cooling. Due to temperature differences, internal stresses arise and various modifications of crystal lattices are formed, leading to the appearance of faults. Welding requires special electrodes and requires uniform heating and cooling of the cylinder block.

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Methods for welding a cast iron cylinder block

To reliably eliminate small defects in the form of cracks, there are several effective methods. Difficulties arise when repairing aluminum alloys. This is due to a change in the properties of the metal when heated, the formation of a refractory oxide film. The aluminum engine block requires some gas welding skills. If cracks appear in cast iron, welding of the cast iron block is carried out in three ways:

when heating everything;
fragmentary heating of the repaired area, used when it is impossible to completely heat the overall body;
electric welding on a cold surface, this method is most popular due to the ease of execution and the quality of sealing cracks.

Hot welding

According to the technology, the part to be welded must be heated to +600-700°C, this is done in special furnaces and furnaces. Craftsmen carry out the process in casings with an asbestos layer. Gas burners are used for this. When heated, the metal retains its plasticity and viscosity. It is better welded by the electric arc liquid bath method using electrodes of the MNCh-2, OMCh-1, OMCh-2, OZCh-2, OZZHN-1, TsCh-4 brands.

The method is used to seal cracks in hard-to-reach places. Special holes are made in the casing to seal defects. Heating is carried out slowly, since a sharp temperature change deteriorates the quality of cast iron.

Cold welding without preheating the block

The process of eliminating cracks is carried out using three methods:

electric arc using flux, cast iron filler rods, graphite or carbon electrodes;
manually using a protective atmosphere (argon), the electrode must contain graphitizers that reduce the fragility of the weld;
semi-automatic with flux-cored filler wire in a carbon dioxide atmosphere. The cold method of metal repair is more economical; it involves heating the area in the weld area to a temperature of + 80°C.

Cast iron welding methods

There are three ways to weld cast iron:

Hot welding. The main and most correct method. It consists in the fact that before working with the electrode, the workpiece is heated to 600 - 650 degrees. This allows you to avoid the formation of compounds with a high melting point, overheating and tension of the metal at the joint. Heating is carried out in ovens, gas or other burners. For home conditions, this method is a stretch, because in addition to the heating device, you need to know at what moments you can work at the welded joint, how to cool the metal and many other nuances.
Semi-hot welding. It is practically no different from the previous method, with the exception of the heating temperature. Here the product is heated to 300 - 350 degrees.
Cold welding. The method does not involve heating the workpiece, but it is based on many other technological aspects, failure to comply with which will lead to the impossibility of making a high-quality seam. Welding cast iron at home with an electrode is carried out in this way.

Welding technology

Now let's talk in detail about how to weld a crack with your own hands. Parts are pressed out at the site of damage. The defect is discovered after hydrotesting; for convenience, the crack is marked with a thick chalk solution. 5 mm holes are drilled at the ends.

To weld a cast iron block you will need:

welding machine with current regulator or inverter;
2–3 electrodes, it is better to purchase universal Zeller 855;
chamfering tool;
brush and hammer for cleaning the seam and removing scale.

The crack must be welded using the following technology:

The seam area is cleaned to a shine and degreased.
Flux is applied to both sides of the edges, protecting the cast iron from heating.
The repair area is heated by a gas burner evenly and gradually, the direction of movement is along the crack.
The seam is formed in small sections, up to 15 cm long per pass.
The resulting seam is heated for about five minutes so that the metal cools slowly. When subjected to sudden cooling, it will become brittle and will not withstand the workload.
The scale is carefully knocked off, and after a visual inspection the joint is well cleaned, especially if the chip is in contact with other parts.

By forging each roller separately, you can immediately eliminate possible defects.

When a defect is found on the engine block, do not rush to replace it. It is better to consult with specialists whether it makes sense to undertake repairs. It is possible to weld a block crack with cold metal in a garage. You need at least basic welding skills to get the job done accurately. Some service stations provide welding services for internal combustion engine blocks; this is much more expedient and cheaper than completely replacing the engine.

The need to weld the cylinder block arises when cracks appear on it. A large number of blocks are made by casting cast iron. Cast iron is a fairly strong and hard material, lends itself well to casting and has a low melting point compared to steel. The negative side of the material is fragility and low viscosity. In this regard, the most common malfunction of blocks is the appearance of cracks.

Rice. 1. Cylinder block

Features of the material

Cast iron is an alloy of carbon and iron, where the carbon content is 2.14%. Which negatively affects the quality of the connection.

The process is labor intensive due to:

formation of cracks and pores;
during processing, the appearance of hardened structures and rapid dulling of the tool;
thin material crumbles from overheating.

According to its composition, cast iron is divided into gray and white:

White ones cannot be welded due to their fragility and hardness. Suitable for grinding;
Gray (high strength, malleable) are easy to machine and have limited weldability.

Technology of welding cast iron with electrodes

There are 2 methods of welding cast iron - hot and cold.

Hot also includes semi-hot.

When hot joining, the part is heated to a temperature of 600-700°C, welding is performed and the cast iron product is slowly cooled in the furnace. With a semi-hot connection, the temperature is maintained at 300-400°C.

Hot and semi-hot welding requires additional equipment. In domestic conditions, a cold connection is used.

Edge cutting

Welding cast iron with an electrode at home requires chamfering. There is no need to degrease or clean the parts.

Chamfering is performed:

Note: sharp edges are not allowed. The sharpness is removed with a suitable tool.

How to cold weld cast iron parts

When connecting, do not overheat the heat-affected area (no more than 80°C). Take frequent breaks between passes. Use multi-pass welding.

first perform surfacing along the edges of the chamfers;
then gradually filling the seam;
After each pass, hot forge the roller.

Make rollers 40 mm long, scattered to reduce heating of the part.

How to weld cast iron using electric welding at home. What you will need:

current source (inverter);
electrodes 3 mm;
seam cleaning brush;
hammer for forging and removing slag;
cutter or cutter for cutting chamfers;
shield and gloves.

first, cutting edges and blunting sharp corners;
then surfacing along the edges of the chamfers;
then gradually fill the seam.

Forge each roller hot. Don’t rush, give the part time to cool (heating of the heat-affected zone is no more than 80°C).

After filling the weld, turn the part over and cut the edges on the reverse side. Perform welding as described above. Observing the temperature regime and forging each roller. At the end of the process, grind the deposited surface if desired.

Video:

Cold welding is used to repair batteries, vices, engine cylinder blocks and other structures made of gray cast iron.

Brands of electrodes for welding cast iron

In this article, you can get acquainted with factory electrodes and homemade electrodes for connecting different types of cast iron.

The table below will help you set the current on the device for different diameters of electrode brands:

The current values are indicated for the lower position of the electrode. For a vertical position, the current is reduced by 15-20 A, except for TsCh-2.

In order to save money, home craftsmen have adapted to welding cast iron with a conventional electrode with copper wire. Video below:

Also, copper wire will help in welding cast iron with steel.

Some craftsmen ask how to cook cast iron with a semi-automatic machine? On metalworking forums, experienced welders advise using PUNCH 11 wire. The connection is made with 2-5 cm stitches with forging, without gas protection on straight polarity. Current 90-110 Amperes depending on the thickness of the metal.

How to cut cast iron

Types of cutting are divided into thermal and mechanical. List of tools and methods:

The grinder is a simple and affordable way. Minus: the cut occurs in a straight line.
Pipe cutters have proven themselves well when working with pipes.
Reciprocating saw.
Electrode.
Oxy-fuel cutting is a good option. Oxygen flux will improve the quality of cutting cast iron.
Mobile installations Thermal cutter 2M (weight up to 5 kg).
Oxygen-lance cutting and plasma.

As you can see, there is plenty to choose from! The grinder is widely used in everyday life.

Preparing the cylinder block for welding

Before carrying out welding work to repair the unit, it is necessary to thoroughly clean it of dirt, oil and other contaminants. Cracks and discontinuities identified on the block must be marked with chalk or other convenient means.

In order to avoid the growth of cracks, its edges must be drilled. Small cracks up to 5 mm can be welded without cutting the edges. Deeper cracks must be made with cutting edges.

Rice. 2. Drilling cracks

The hole must not be made through, but only until a gap appears along the entire length of the crack. The crack prepared for welding should resemble a joint with a V-shaped bevel of the edges. This is done so that during welding all gases and impurities contained in the welding materials and base metal can escape to the surface of the weld.

Video on welding cast iron cylinder blocks using the argon arc method

In the next video, the author welds a crack on a block using the argon arc method with a non-consumable electrode.

How can you weld or solder a cast-iron engine block?) It may seem funny, but some people say that it’s possible, some tricks the Chinese are selling that can be soldered. But I would like to know your opinion and advice?

Such a thing, on the engine block where the bend of the joint with the oil pan is cracked, oil is leaking from there.

The crack is due to the fact that the previous owner, when removing the pallet, hit it past with a hammer, the mark of the chisel is clearly visible)))

We tried it with sealant, it’s enough for about 3-4 thousand. I’m afraid that this crack won’t go any further.

Welding an engine block with argon - does it make sense?

There are different types of car engine repairs. You can simply use recovery after the breakdown of some internal and peripheral parts. And it is possible to restore after serious damage. These types of breakdowns include cracks in the cylinder block, chips in functional areas of the unit and various other features. With such breakdowns, it is simply impossible to operate the power unit, otherwise it may rupture during the process of pressurizing the chambers. There are two options for getting out of the situation. The first is replacing the damaged part. You need to select a suitable version of the engine block or a specific part; this can be done by disassembling, but with the help of a good specialist. This way you can make a really high-quality selection and buy reliable spare parts for restoration.

The second option is argon welding. Many owners of cars with damaged power units perform argon welding. This is a fairly high-quality process of connecting aluminum alloy parts to each other. However, this is not the best solution for load-bearing main engine parts. If the cylinder block is cracked, it is better to buy a new one. Here welding will not be an appropriate solution to the problem. This is one of the most expensive options for car breakdowns, but sometimes you can get by with more or less affordable costs. It all depends on the type and location of the crack, as well as a number of other features. It is important to complete all tasks really efficiently in order to restore all parts and obtain high reliability of the power unit.

Features of the material used for the manufacture of cylinder blocks

Car engine blocks are usually cast from cast iron.
This material is an alloy of iron and carbon, the content of which is 2.14%. This negatively affects the quality of the connection. Main difficulties of the process:

formation of pores and cracks;
the appearance of hardened structures during processing, the tool used quickly becomes dull;
As a result of overheating, the thin material crumbles.

Cast iron may differ in composition:

gray cast iron is a malleable, high-strength material, easy to process, limited weldability;
white cast iron is a fairly hard and brittle material that can be ground, but cannot be welded.

Replacing the cylinder block and abandoning welding is the right decision

Any welding, even by the most professional performer, will not be as high quality as installing a new cylinder block. When there is a crack in this unit, the component parts of the unit quickly break down and everything fails. Even with professional welding, it is impossible to maintain all factory dimensions down to the last micron. The cylinder block is replaced as follows:

Based on the make and model of the engine, the specialist searches for spare parts, selects all peripheral parts that will also have to be changed, and forms a budget;
Also added to this budget is the cost of work, which each master evaluates in his own way, but it is better to contact a professional car service station;
Next, the engine is disassembled, the problem and its effect on all other parts, such as pistons, connecting rods, rings and seals in the unit, are studied;
a new cylinder block is installed, the necessary parts are assembled in the right place, and at each stage several checks are performed, which proves the quality of the part;
After assembly, it is necessary to diagnose the power unit in different planes, then test drive the car with an understanding of all extraneous sounds and noises in the engine.

If a used cylinder block is being installed, special care must be taken during the engine testing and inspection processes. However, with professional selection of the part, no negative features of the operation of the power unit should arise. That is why replacement is the optimal process for such a breakdown. But welding is not always suitable, even if done professionally.

Additional Information

After completion of the work, the surfaces must be treated (for example, if any unit is being installed). In a workshop setting, a milling machine is used to level the plane; in a domestic situation, an angle grinder is used. At the same time, it is important not to damage the mating surfaces with high precision processing (for example, for installing a clutch bell, front cover or head).

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Welding an automobile cylinder block requires a highly qualified worker. Mistakes made lead to a decrease in the strength of the assembly; with cyclic temperature changes (the part warms up to +90°...+95°C and cools down to ambient temperature), new cracks may appear. In case of a large area of damage, it is possible to install patches from a sheet of steel, which are welded into cast iron. The decision on the method of restoration and the feasibility of repair is made by the master, based on the qualifications and equipment available.

Modern technologies for welding aluminum with argon

There are many processes in a modern car that can be performed using argon. It is quite easy to restore wheels made of light alloy materials using this technology. But the basis is the repair of engine housings and blocks, as well as gearboxes. In the process of welding engine elements with argon, the following important tasks are performed, which are performed only by specialists:

research and preparation of each element for welding work, cleaning the surface and searching for additional material if necessary, to seal the hole;
preparing the site according to safety measures, we are talking about welding at very high temperatures with a certain risk of damage to people and objects around;
implementation of the welding process itself, with careful supervision of all surrounding parts, very careful execution of the main necessary task;
the use of additional compounds for surface treatment to avoid its oxidation and other unpleasant processes after all welding work has been completed;
cleaning the welding site if necessary to obtain a smooth surface that meets the manufacturer’s technological requirements for operation.

Features of welding engine blocks made of cast iron

There are many methods for welding metals, but in order to obtain the most reliable connection of individual parts, it is necessary to use proven technologies that can guarantee the effective performance of welding work.

Welding technology

Regardless of the conditions under which a cast iron cylinder block is welded, it is necessary to strictly follow the following requirements for performing this type of work:

Using a metal brush, first thoroughly clean the surface of the product (until it shines).
To remove the oxidizing film and various chemical deposits, the cleaned surface is degreased with special compounds.
The required flux is selected and laid out along the edge to be welded.
At the next stage, the metal is heated to the required temperature using a gas burner. This will take a few minutes, but it is not recommended to start welding right away.
The metal can be joined after it reaches the specified temperature. The cylinder block is welded in small sections - up to approximately 15 cm in one pass.
After creating the seam, the metal must be heated for a few more minutes, gradually reducing the temperature. Rapid cooling of the part or sudden temperature changes should not be allowed.
The created welded joints must be checked: in production this procedure is carried out using special methods, in domestic conditions a visual inspection is carried out.

Cracked car engine block

There are three options for welding cracks in cast iron cylinder blocks:

heating the entire product;
heating only individual sections of it where cracks have formed;
cold welding of a product without preheating.

If, after welding the crack, the surface of the cylinder block comes into contact with other engine parts during operation, it is subject to additional processing. Excess welding metal is removed using sandpaper, a file, or an abrasive.

Hot welding

Heating of the entire engine structural element is carried out during welding using oxygen and acetylene. The connection is made by forming an electric arc using steel or cast iron electrodes with a special coating. The product is slowly heated to 600–650 degrees, for which a steel casing with an asbestos gasket is used. This technique is used to weld cracks in hard-to-reach areas of the part.

When does it not make sense to weld with argon?

Often during the operation of a car, it becomes necessary to change the sensor in the engine housing or spark plugs. It may well turn out that these elements are too tight. In this case, the master or owner may apply excessive force and simply break off a piece of the unit. If this was done at the place where the spark plug was installed, you will have to buy a new block. When attempting to weld, the following processes will occur:

the technician will restore the damaged area as carefully as possible, but the seat diameter can no longer be made ideal for the candle;
you can use the option of melting, and then drilling and cutting the required thread, but it is also impossible to maintain the required installation height of the candle;
if we are talking about a sensor, it is also simply melted and not used in the future, because otherwise you will have to perform incredibly difficult work to restore the installation site;
if there is a crack in the body itself from the outside, you can be sure that there is a crack on the inside, so it can only be welded in certain situations that a specialist knows about;
unprofessional argon welding will bring big problems, in this case it is better not to do any work with a broken cylinder block, but simply buy a new one.

Welding with an argon mixture occurs using a tungsten electrode, which heats up to a temperature of about 4000 degrees at maximum mode. This requires not only increased caution, but also fairly high professionalism. Simply place the electrode in the wrong spot, and it will simply make another hole instead of welding the necessary elements of your engine.

Restoration of blocks and heads. Bend, wear and cracks

Restoring the engine... A seemingly simple procedure. I unscrewed the liner caps, took out the pistons, and checked the diameters and surfaces. I changed the rings, or at least the same liners, plus bored out the cylinders, switching to repair sizes if necessary. As a rule, for the average person, engine repair looks like this. In reality, and often, restoring an engine involves more than just these relatively simple operations. We do not mean the sleeving of blocks that we talked about. Instrumental processing of them and their heads is required, sometimes non-trivial solutions that can bring a worn-out engine back to life. Without pretending to be a definitive analysis (after all, even in this area there is a certain pluralism of opinions), we will present the view of a person who has been engaged in such restoration of “hardware” for many years. He has a wealth of experience and his own point of view.

Typically, such structures do not strive to loudly declare themselves, to convey information to the end consumer - there is no street advertising, no promotions or discounts that can interest the client. Not even a flashy building in a busy area of the city, a beautiful room, a rest room for visitors. Only harsh industrial reality - industrial workshops with concrete floors and machine tools. In our case - exclusively imported, with software. Plus a website and, of course, a must - connection with services from where blocks and heads come for repairs, as well as work with enterprises that have a fleet of trucks or special equipment. After all, it is from the latter that the main flow of parts for processing comes from. But we are certainly interested in passenger engines.

In general, more than one such “production” can be found in regional or regional centers. What can I say, we learned how to restore blocks and cylinder head. True, it is not the same everywhere. For example, my interlocutor, when asked whether they will take on the liner of all motors, directly answers - no, there are unpleasant but common exceptions. Thus, Vagov “fours” and “sixes” have extremely thin inter-cylinder bridges. And the cooling channels are connected closely to the cylinder walls themselves. When boring they open and... What to do? Is it technically difficult to put cartridge cases on glue? Or jam the channels, which can lead to overheating? In short, there is no technology yet that simultaneously ensures the tightness of the cooling system and trouble-free operation of the engine as a whole. Although work in this direction is underway. Nevertheless, a number of services will undertake this and even promise results. There is no need to delude yourself - it is possible that the engine will “be enough” for the time of selling the car, but longer...

Here is one example of a Vagov engine - 3.0 TFSI. Pay attention to the jumpers between the cylinders. However, this is a topic for another conversation

The warranty issue is also an interesting one. However, you shouldn’t hope here in any case - they almost certainly won’t give it anywhere. The fact is that division of labor is usually practiced here - some disassemble and assemble the engine, others process the blocks and heads on machines. Tying a guarantee to a specific structure is difficult.

They also refer to the practice of replacing failed engines with so-called short blocks (examples of these in the photo below) - blocks with a crankshaft and a piston, but without a sump, attachments and, most of all, without a head. As a rule, they are not guaranteed.

Finally, it is noted that automakers are now eliminating any kind of tooling of blocks and cylinder head. If there are changes in coatings or geometry, the hardware is thrown away. So we do everything without manuals, taking into account the experience already gained. But without this work it is impossible. In fact, don’t throw away such financially intensive parts just because they “have developed a curvature somewhere.”

Level up the “resting area”!

It turns out that you even need to remove the head by unscrewing the studs or bolts in a certain (reverse) sequence. After all, when mounting it on a block, we do this precisely so that the part does not move. Why should they deviate from this rule during dismantling? True, there are features associated with generations of engines. Until the early 90s, paronite gaskets under the cylinder head were almost universally used. Having a limited resource, they could compensate for some curvature of the mating surfaces obtained during repair or operation. Between 1993 and 2000, manufacturers switched to metal gaskets. With a significantly longer service life (in fact, they are designed for the entire service life of the engine), they are no longer able to fill small cavities and “level” the removed surfaces.

What kind of caverns? For example, traces of a gasket breakdown, when a gas stream, breaking through between two planes, gnaws out the metal. This is invisible to the eye, but can easily be determined with measuring instruments (in the photo above on the left there is blackening on the jumper between the cylinders). If the plane is not brought out, there may be further penetrations by gases or, say, seemingly causeless entry of antifreeze into the oil or vice versa. But on the mating surfaces there is also something that is visible to the naked eye - cavities from the consequences of cavitation of the coolant (photo on the right), when additives are activated in it or water is used altogether.

The last photo, of course, is a blatant case. Apparently, this is already a sentence. However, somewhere they will undertake the restoration of such cylinder heads. In light of such situations, our respondent notes that the maximum that can be removed from the mating surfaces is a few tenths of a mm. Moreover, the value applies to old gasoline engines, developed back in the 90s and having a compression ratio of up to 9.5-10:1. On modern installations, the curvature of the block and cylinder head should not exceed 0.05 mm. For diesel engines the situation is more complicated. In addition to the block and head, it is necessary to process valve seats, and in extreme cases even the ends of the pistons.

We sorted out the caverns. Why, in addition to improper installation and removal of the head, does warping of the mating surfaces occur? Due to boiling and long runs! It does not matter how many cylinders and what their arrangement the engine has. Both “opposite” and in-line “fours” with “sixes” and V-types are deformed. But, for example, it has been noticed that on Subarov EJs, when overheated, the block can move more than the head. Among modern engines, the N-series from BMW is often used for cylinder head milling. And not necessarily after boiling, gasket breakdown or with significant mileage. We can assume with a high degree of confidence - due to the extremely lightweight design and intense operating temperature conditions.

In a word, if there was overheating/burnout, the engine has a decent mileage or it was developed relatively recently - in general, in most cases - a high-quality result during repair can be ensured at least by checking all mating surfaces.

Despite the fact that there are descriptions and videos on the Internet about how to measure the “bevel” with a ruler and then polish it manually, it is better to trust specialists and machines. Only in this case will it be possible to guarantee a smooth surface. In the photo on the right you can see the newly formed mating plane and the remains of the old one - another pass of the cutter is needed.

Bed matters

A curious thing is that the block and head are ordinary blanks, no matter whether they are made of cast iron or aluminum, albeit with a precise internal organization of channels and calculated in terms of rigidity. And how they can suffer! Seizures in the cylinders! Warping and wear of mating surfaces! And that is not all. The crankshaft and camshaft beds are those parts of the block and cylinder head that often become victims of the owner’s negligence and the unprofessionalism of the craftsmen.

The beds of the heads, by the way, lead together with the “resting places”. Usually by 30–50% of the latter. This is also possible with blocks, but in exceptional cases. Once a 2JZ-GTE of a well-known drifter in the country came in for repairs. So it was necessary to remove both the mating surface and the crankshaft bed. But there were 800 or more “horses”. With such a boost, multiplied by races that are not short, like, say, in drag, such a result is probably natural. Of the serial engines, the Mitsubishi 4D56 in versions before the use of common rail suffered from the same thing over long runs. Moreover, there the crankshaft bed was bent so much that the crankshaft itself broke. They installed a new one and after a while everything repeated itself. In the mid-2000s, with the advent of a new fuel system, the unit was strengthened, and the breakdowns stopped. And for Minsk diesel engines D240 and D245 (installed on many GAZ models), the crankshaft bed is often crooked from the factory.

To be fair, we note that more often than not, shaft beds are damaged not as a result of tuning or as a result of design miscalculations, but from oil starvation, critical temperature conditions and non-compliance with tightening torques.

Wear of the camshaft bed during oil starvation is not very common, but it does occur. If you don’t keep track of the level/quality of lubrication, the bed is one of the first to suffer. In addition, it is subject to natural wear and tear - on fairly similar engines. There are different restoration options: making bushings (pictured), welding, spraying, moving the camshaft axis. All these methods require boring the bed to a nominal diameter.

The crankshaft bed, in addition to oil starvation, often suffers just during engine assembly.

One example of an engine with a solid crankshaft bed is the Mitsubishi 6G74 (top left). And it is often deformed! Repairs are made by installing inlays and boring to a standard size. Here, as in the case of the cylinder head, it is very important to maintain a minimum deviation from the previous shaft axis. Otherwise, if there is a discrepancy of just a few tenths of a mm, problems with the timing gears, crankshaft seals, and the connection between the shaft and gearbox are possible.

There is another option for restoring beds - various types of material spraying: gas-dynamic, plasma, detonation.

The most popular process of gas-dynamic spraying (in this case, using the example of a worn main liner cover) consists of applying a layer of metal powder to the part, which is accelerated by an air flow to enormous speed and binds to it when it hits the surface. Then surface treatment and... My interlocutor admits that he does not provide such a service. Because it is dirty for the premises, harmful for employees and it is not always possible to obtain the original surface quality and its hardness.

Let us add on our own that gas-dynamic spraying (the video below shows how this happens) is a fairly popular technology for restoring various parts. True, in a number of cases regarding sliding surfaces, manufacturers themselves or equipment suppliers note that it can be restored, but the wear resistance of the coating will be lower than in the factory version.

Welded passions

Alas, it happens that the machine industry is powerless to eliminate the consequences of operation. Which? For example, damage to combustion chambers. Cracks in the bridges between valves caused by overheating or mechanical damage. Deep cavities from the same cavitation. It doesn’t matter if the engine is old and common. You can find the head separately, or purchase the entire contract one. What if it’s rare, exclusive? Finally, just modern ones, for which buying a used unit is a dubious option?

There is an exit. The country has been welding cracks in heads for a long time. At some time, they began to restore combustion chambers, mating surfaces and walls between the cylinders by welding. Services specializing in such operations note that in order to obtain a high-quality result, before welding/surfacing it is necessary to heat the entire part, and also use filler material whose composition matches the material of the cylinder head or block.

In “our” structure we agree with the nuances of such specific welding work. And yet they doubt the final result. How to choose a filler material so that it completely matches the alloy of the block or head (and not just aluminum to aluminum)? Tungsten electrodes, which are used in argon arc welding, leave behind small cavities or inclusions, which are then difficult to process. The situation is the same with welding cracks in the heads. Some people do it, but the results are usually short-lived. What can we say about cracks in the cylinder walls. As mentioned above, modern engines are not always properly lined. And here is such a complex thermal process. What is the chance that even when heated to a temperature close to the “welding” temperature, the block will retain its geometry and tightness during the process?

“Knee”... about the knee

People here are also quite skeptical about the restoration of crankshafts. More precisely, they could tackle this at the proper technical level (purchase expensive equipment), but they do not see financial prospects. But they give examples of what not to do. It is known that crankshafts sometimes bend. So, no one bothers with specialized equipment for leveling them. A dull chisel and a sledgehammer to help, in general, almost hit the knee. Is it correct? Cheap, definitely! It is difficult to predict how long it will last. Still, certain intervals of time and deflection are maintained on the equipment. In any case, after editing the crankshaft, it is necessary to check it for cracks, grind it and balance it.

Restoring crankshaft journals is possible, but the technological process is very complex, and in some cases the client cannot count on high quality of the restored surface.

The options are different - welding of tape, welding of wire, application of material by spraying, selection of a repair size liner or an alternative one. The problem is that very few people can properly polish a crankshaft. For the most part, shafts are ground using a simplified technology, without restoring the radius - the fillet. And without it, the shaft takes the bending load much worse, which can lead to its breakage. Finally, it is impossible to help those owners whose engines (for example, Honda K and J series) have chipped camshaft cams. Theoretically, restoration is possible, but there are no practical examples yet.

This is a view that may very well seem subjective and even biased to someone. We know that there are “oppositional” opinions. And besides them, there are other features of the restoration of engine hardware. Therefore, if necessary, we will continue the conversation.

Welding an engine with argon and subsequent sale - we are clogging up the car market

The attitude of Russian people towards the automobile market is simply surprising. Many people sell their cars, realizing that in two days they will have an irreparable problem and will have to replace expensive components and assemblies. It is enough to simply understand how much anger and hatred the buyer will feel towards you, so as not to make such a mistake. If the cylinder block in your car is cracked, you should work around the situation as follows:

replace the unit with a used, but high-quality one, get more money from the leisurely sale of the car without special discounts and with confidence in the high quality of the car;
replace the cylinder block with a new one and continue driving the car without selling it, enjoying the fairly high quality of the revived power unit;
indicate in the sales advertisement that the car is damaged, there are certain problems that can be solved for a certain amount, which will result in a discount;
when meeting with a potential buyer, honestly tell them that there is a problem with the engine that needs to be solved urgently, and reveal your readiness to concede the selling price;
weld the engine with argon, and then, when selling, honestly admit this and show the place of welding, this will relieve you of any responsibility for the further behavior of the unit.

It is often possible to gain no more than a few hundred dollars by concealing all the details of car repairs from the buyer. And this amount is definitely not worth it to continue to clog up the automotive market with not entirely suitable equipment. Such decisions can also be disastrous for you if the buyer decides to look into the whole situation. However, for now there is no need to expect a civilized market in Russia. We invite you to look at more or less high-quality restoration of microcracks using argon:

Crack on the sleeve. Can I brew it?

Good afternoon, dear oppositionists. Suddenly a problem appeared. I gave worn out cylinders for boring. Yesterday when I picked it up I noticed a crack on the sleeve. In short, conversations with the seller led to nothing. This means there is a crack at the very bottom of the sleeve. 1.5 cm long. The inside is smooth, but the joint is felt from the outside. It turns out that when I bored it, it was already there. Now I’m on a “business trip”, all the manuals, Kotov is also at home. I won't get there soon. Search used. Tell me, is it possible to weld the crack from the outside, maybe it will lead to the sleeve? There is a welder with autogen and electric welding.

Photos, I don’t know if I can post them - I’m on my phone.

without appeal, to the trash heap. You can, of course, stop the crack by drilling a hole at the end of the crack (1mm is enough), but this is just to get somewhere and it’s better not to try to spin the motor.

Maybe press out the sleeves and replace them if this is possible in the Urals

crovex, if the pots are made of aluminum, you can re-sleeve them. In general, it’s better to take a new CPG, ours costs 2100: pots, pistons and rings, if you ask a guy at the market, he’ll give you rings from shaggy years.

These are photos. didn’t cut it – from the phone.

Crap. bad, very bad. I, in principle, thought so, but hoped for the best. Very very bad. sooo bad

stop using this bullshit. Spent 5 minutes on one picture! here: https://www.radikal.ru/ - the boiler is apparently Ural cast iron. dead man When using it, you can fly into the entire new motor.

I got exactly the same crap (((((((((((((also after boring. And there is some kind of noise. Tomorrow I’ll take the other cylinders to the boring!!

If the pots are made of aluminum, then you can re-sleeve them.

I will look for 1 used cylinder, nominal for boring. The pistons are repaired, the rings too, but there is no money for everything and they are lying (((

But re-lining will be more difficult and more expensive.

Pegasus2, as far as I know, is available with a pressed sleeve and with a filled one.

For me, one turner put the zaza sleeves into the Ural cylinders, bored them out and pressed them into place, they turned out to be like 2 layers. He said that the cast iron on the zaza is better, I rode on them for 2 months and took them off, I was afraid they would suddenly burst.

Let's sum it up

As you can see, the cylinder block is welded with argon most often for sale. This is not the most reliable option for repairing a power plant. But there are masters who can do everything quite efficiently. Often, after a visit to them, the owners decide to sell the car, as they are constantly worried about the presence of handicraft interference in the operation of the engine. Any sound becomes scary, it seems that the engine is now going to shatter into small pieces. Therefore, when repairing a car for your own further use, it is much better and easier to perform a normal repair with replacement of the cylinder block.

When making repairs for sale, it is better to refuse any work altogether, simply discounting the price to the buyer for the amount of repair work. If the new owner wants to cook the engine with argon, that will be his problem. You will come out of this situation fairly honestly with an untarnished reputation. You should not carry out cheap argon welding in a garage car service, and then quickly go to the car market in the hope of selling the car and forgetting about all these problems. Through mutual scams, car owners have already made the car market a dangerous place where they can lose all their money. How do you feel about repairing unit housings and gearboxes using argon welding?

How engines are restored using welding

Welding of various engine elements was in great demand in an era of shortage of spare parts and restrictions on the free replacement of units. However, even today this operation has not lost its significance and is capable of bringing the engine back to life from the other world when, for one reason or another, it needs to be saved.

Serious damage to the cylinder block or its head is not a death sentence for the engine. Yes, on the one hand, it is easier to change the damaged element. Now it’s not a problem to buy, for example, a new short block (cylinder block assembly). But in some cases, the price of such a purchase may be equal to half the current cost of the car itself. Therefore, repairing engine components using welding may be a more profitable option.

Theory and practice

With the help of welding, it is possible to successfully treat cracks, restore the walls between the cylinders, and even seal a hole in the block punched by a connecting rod. In each specific case, only the master himself determines the feasibility of such complex repairs and its cost. The limitation is the location and nature of the damage. In some cases, successful repair is impossible in principle, and in others the cost of the issue is very high.

The specifics of welding depend on the material used to make the parts. It is easiest to work with aluminum alloys - their melting point is low, and the metal flows well. Things are much more complicated with cast iron. To work with it you need higher temperatures and more expensive equipment.

Any welding work involves strong local heating of the part, as a result of which it can “lead” (violation of its geometric dimensions). Therefore, it is very dangerous to carry out such activities on a motor installed on a car, and without final quality checks. The banal welding of some torn bracket with this approach can lead to the fact that the nearest cylinder will move, and the piston in it will generally jam. Professionals very often encounter negative consequences of such welding to varying degrees of severity. Repeated repairs are much more difficult for the master himself and more expensive for the client.

High-quality welding technology involves preheating both aluminum and cast iron parts. Elements made of light alloys are heated to approximately 250ºC, and elements of heavy metal - up to 350–400ºC. More is possible if the equipment and the welder’s patience allow working with a hot part. In this case, the consequences of strong local heating are minimized. After welding, the parts are slowly cooled.

After any type of welding, it is necessary to check the geometry of the parts, for example, the diameters of the cylinder along the entire height and the plane of the mating surfaces of the block or its head, as well as their crimping in a hot water bath. If some elements still fail, then their geometry is restored to factory parameters.

Light alloys

Although aluminum alloys are quite convenient for welding, they also have their own unpleasant features associated with the quality of casting. When working with the same part, there are areas in which the metal melts very well, while in others it foams and a lot of slag and dirt float up. Experts note that this is often not related to a specific automaker.

Welding on alloys is carried out using special aluminum wire. The cracks are excavated to the base and new metal is deposited on top. Large holes are sealed using high-quality aluminum patches.

The cost of work depends on the specific case, because the complexity of their implementation is always different. It is very difficult to determine the average price tag, but rough calculations can be made. Welding a hole in the wall between the cylinders today can cost from 5 thousand rubles, and repair by installing a patch can cost from 7–8 thousand. Welding the entire mating surface to restore its plane for an inline four-cylinder block and its head costs approximately 9 thousand rubles. for every detail.

Cooking cast iron semi-automatically

Cast iron is widely used to make pulleys, blocks, and commutators. It has good casting properties, which makes it possible to produce products of various shapes from it. But this material also has disadvantages - it is quite fragile. Impacts often cause chipping of sides on pulleys or cracks in pipes. To correct the situation and restore the product, they resort to various methods of joining metals. One of them is semi-automatic welding of cast iron. What are the features of this method? How many options are there for using a semi-automatic machine? What supplies are suitable?

Welding process

In the previous paragraph, we discussed the preliminary preparation, and before starting welding, we need to consider the main technological points:

Connection polarity is reverse;
The power of the welding machine is minimal for a given electrode thickness;
The length of one continuous weld should not exceed 30 - 50 mm;
It is necessary to prevent overheating of the metal due to frequent breaks;
The first and last layers of multilayers are hammered with minimal force.

The table below will help you decide on the welding mode:

We have considered the main preliminary points, but the main question remains: “How to cook cast iron using electric welding?” There are two ways: on studs or in layers. Let's look at each option separately.

Welding cast iron using an inverter using studs

After installing the studs, you can begin welding the seam. Metal is placed layer by layer around each pin to form a patch. You can prevent heating above 80 degrees by doing the work in a checkerboard pattern or alternately at opposite ends. The final point in this type of welding is the connecting seam, which connects the welded metal between the studs.

Multilayer welding

First you need to make sure that the chamfers are created correctly. Then, using a special electrode, observing the temperature regime, we begin to fuse the first layer. It is fundamental and will determine the success of further work. Each layer, while still hot, must be hammered. If there is access to the back side of the part, then after the first layer on one side you should turn the product over and fuse a similar seam on its back side and only then proceed to complete the multilayer welding of the upper and then the lower part.

Surfacing must be done from the edges, and many layers must be gradually created. The main thing is not to forget to forge each layer. If you don’t know how to check the temperature of a part, then use the random technique. It consists in forming a seam alternately at different joints. When the weld is completely ready, the surface deposited on the cast iron must be ground.

If you are faced with the need to weld cast iron and you only have an inverter, then at home you can repair cracks or apply patches to non-load-bearing structural elements. You will already have almost everything you need, such as a mask, protective gloves and clothing. You will only have to purchase special cast iron electrodes, or make them yourself. This article describes two ways to weld cast iron at home. Which one suits you best – decide for yourself. But remember - when there is a need to restore a product that requires heavy loads, it is better to turn to professionals.

Why is it difficult to cook cast iron?

The question of whether it is possible to cook cast iron with a semi-automatic machine worries many people for good reason. The connection of the sides of this material does have a number of specific features:

The high fluidity of cast iron manifests itself when forming a seam where the weld pool is too liquid. Because of this, it is more difficult to visually control the quality of compound formation. When trying to weld thin plates of cast iron, a common defect is metal burning and droplets leaking onto the opposite side. To prevent these undesirable manifestations, graphite pads are used to support the plates on the reverse side. You can learn how to form a seam when the metal has high fluidity by practicing on training products made of similar alloys.
The second difficulty is the low melting point of the material. Due to the high temperature from the electric arc, the cast iron in the welding zone quickly overheats. As a result, upon cooling, microcracks form between the base and superimposed metal. Overheating of additional impurities in cast iron (manganese, silicon) leads to the appearance of cementites in the weld structure, which complicates subsequent processing of the joint with grinding tools. To prevent these defects, they resort to preheating the material and a gradual cooling procedure for the product.
It is difficult to weld cast iron efficiently due to the large number of pores that appear as a result of the release of carbon when interacting with oxygen. Even with subsequent processing, the seam may have an unattractive appearance and poor resistance to fracture. To protect the connection, copper-plated wire is used, and the work is carried out in an inert gas environment. A prerequisite for welding cast iron is the flux content in the wire.

Features of welding cast iron, types of cast iron

Experienced welders can determine the weldability of cast iron from just a cut. It is believed that if the structure of the metal is finely dispersed and close to gray in color, then such cast iron can be welded much easier than coarse-grained metal of dark shades. If we are talking about welding parts that were in an oil environment or were subject to regular oxidation in an aqueous environment, soil or other similar conditions, then such a welding material will not be suitable. Since cast iron is a metal with limited weldability, it is worth taking into account its following features:

The metal is fluid, so the main and only correct welding position is the bottom one.
If you do not observe temperature conditions and chop the metal, then when the carbon burns out, pores will form.
Low ductility and non-compliance with temperature conditions are the main causes of stress at welded joints.
Molten iron can create oxides that will have a higher melting point than the parent metal.

The main problem you may encounter is the formation of cracks at the welding points when the part cools.

This can only be solved if we fully adhere to the technology, in our case - cold welding.

Welding methods

Depending on the purpose of the product, three types of semi-automatic welding of cast iron are used. They differ in the speed of work completion and material costs.

Cold method

This is the easiest way to quickly join high carbon iron plates. Welding is performed immediately on a material whose temperature is equal to the ambient temperature. The cold method is used on non-critical butt joints that will not be subject to loads. The method is ideal for surfacing worn surfaces and machine parts made of cast iron. Thanks to the continuous wire feed, you can quickly arc and complete a large amount of work in a short time. As you can see in the video on semi-automatic welding of cast iron, the result from the cold method is satisfactory.

Semi-hot method

The semi-hot welding process differs from the previous one in that the cast iron workpieces are preheated to a temperature of 350 degrees. For this purpose, forges are used, in which the heat from the coals creates the necessary conditions. This preparation contributes to a more gentle reaction of cast iron to the high temperature of the electric arc, resulting in the formation of fewer cracks in the heat-affected zone. The technology is used on products that experience some stress during operation.

Hot method

This method is used where a high-quality connection is needed that has high tear and fracture resistance. The product heats up to a temperature of 600 degrees. For this purpose, devices producing induction currents are used. The cables are connected to the cast iron part, and a special measuring device signals the temperature reached. After this, semi-automatic welding is performed. To minimize cracks, after welding the product is left in the ash until it cools completely. Depending on the thickness of the structure, this period can reach 24 hours. The method allows you to weld cast iron reliably and efficiently, but is characterized by high time costs and the need for additional equipment.

Welding cast iron with an electrode at home using an inverter: which one, how to do it correctly

Cast iron is an alloy of carbon and iron, which also contains alloying additives and impurities.

Cast iron parts are widely used not only in industrial and production areas, but also in everyday life.

Cast iron products for private use: plumbing elements, fence structures, car parts and much more. The active use of this alloy leads to the need for welding work.

The main difficulties in welding cast iron that home craftsmen encounter:

due to the fluidity of the alloy, it is recommended to carry out welding in the lower spatial position;
non-compliance with temperature conditions leads to overheating of cast iron, which can cause the formation of pores and stress in welds;
cast iron in a molten state can release gases , which will negatively affect the quality of the connection;
Accelerated or uneven heating or cooling can promote cracking .

In order to obtain a high-quality connection of cast iron products at home, it is necessary to take into account these specific characteristics, as well as correctly prepare the working surface, select the correct welding mode and electrode.

Preparation for welding

Preparatory operations must be carried out carefully and carefully, as this is one of the fundamental principles of obtaining a high-quality connection:

the structure is cleaned of dirt, debris and dust;
then you should degrease the parts with a solvent, for example, acetone;
when working with thin cast iron, you need to use pads to remove heat ;
edge cutting should be done before welding thick-walled products; for this, a file or grinder is used;
cracks must be drilled along the edges and cut to their entire length; an alternative method is to cut out the cracks and round ;
depending on the chosen welding method (hot or cold), the product is heated or not. heated using various equipment: ovens, gas burners, or using improvised means: a blowtorch.

Welding methods

Experts distinguish 3 methods of welding cast iron:

Hot is carried out by heating the cast iron parts before making the connection, the temperature is 600-650°C. This method cannot be used at home.
Semi-hot is practically no different from the previous method, the difference is only in the heating temperature, the product is heated to 300-350°C.
Cold implies the absence of heating of work products. Welding cast iron with an electrode at home is carried out using this technology.

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How to cook cast iron with an inverter and a consumable electrode

Welding cast iron using an inverter and a consumable electrode is most often carried out using the cold method. Important components of successful work are: the correct choice of electrode and optimal welding modes.

Electrodes OZCH-3

The performer must make the connection with special electrodes containing nickel and/or copper:

OZZHN-1;
OZCh-2;
OZCh-3;
OZCh-4;
OZCh-6;
MNC-2;
TsCh-4.

Recommended welding modes for some of the listed brands:

Electrode brand	Current strength for an electrode with a diameter of 3 mm.	Current strength for an electrode with a diameter of 4 mm.	Current strength for an electrode with a diameter of 5 mm.	Current strength for an electrode with a diameter of 6 mm.
TsCh-4	65-80	90-120	130-150	–
OZCH-2	90-110	120-140	160-190	220-250
OZZHN-1	100-120	130-150	160-180	–
MNC-2	90-110	120-140	160-190	210-230

The following technological features should also be highlighted:

the length of one continuous seam should not be 30-50 mm;
frequent breaks in the welding process will help eliminate the possibility of overheating; temperatures above 80°C are unacceptable;
polarity is reversed.

This welding method can be performed in two ways: using studs and in layers.

1. The studs are equipped with threads, which allows them to be screwed into the edges of the product being welded. The studs should be staggered/staggered to prevent overheating during welding. The dimensions of the studs depend on the thickness of the workpiece; when selecting them, you should rely on the following recommendations:

diameter – 0.3-0.4 product thickness, but not more than 12 mm;
screwing depth – 1.5 times the diameter of the stud, but not more than half the thickness of the product;
the height of the protruding part of the pin is 0.75-1.2 times the diameter.

After installing the studs, you can start welding. Metal is deposited around each pin, layer by layer. Then the performer needs to weld the space between the studs, which remains untouched, and make one or more connecting seams.

2. Multi-layer welding is performed after cutting the edges. The presence of sharp corners is not allowed. Surfacing should be done from the edges. The first layer is the main one, so during its deposition you need to carefully monitor the welding mode. Each subsequent layer, except the first and facing ones, must be forged with a hammer, without cooling.

The following video demonstrates the Zeller 855 cast iron electrode, but from the video you can see how welding is done.

This information will help the contractor learn how to cook cast iron with an inverter using electrodes on cast iron, and easily carry out the connection work.

Welding with conventional electrodes

In order to save money, you can use ordinary (steel) consumables instead of special ones. General purpose electrodes have a more affordable price.

The technology of multilayer welding with conventional rods is practically no different from the method discussed above, which uses special rods coated with non-ferrous metals. The stages of work are similar.

The only difference is that the layers following the first are deposited not with a special electrode, but with a regular one.

Attention! Welding cast iron with electrodes not intended for this purpose is possible, but we do not recommend using it in any critical connections! This information is provided only for welding for experimental purposes.

Welding with cast iron electrodes

This welding method can be carried out using a cold or semi-hot method. A little preheating will improve the structure of the weld metal.

Cast iron electrodes are cast rods coated with coating, used to correct defects in cast iron. This type of consumables includes the following brands: MNCh-1; OZCh-1; OZB-2M.

Welding is carried out using direct and alternating current. The current value is determined as follows: 50-60 A per 1 mm. electrode rod. [ads-pc-3][ads-mob-3]

Welding with non-consumable electrodes

Welding cast iron using this technology is carried out in a protective environment of argon or fluxes, the main component of which is borax. Cast iron or special rods containing nickel, aluminum and copper are used as filler materials. Welding cast iron is carried out using tungsten, carbon and graphite electrodes.

The most common method is argon arc welding (AC TIG). In order for the work to be successful, you should adhere to several rules:

Thorough cleaning of the surface from debris and dirt;
the workpiece must be fixed at several points;
It is recommended to use slight preheating of the product; for this you can use improvised means. It should be remembered that the presence or absence of heating depends on the type of cast iron being welded;
the additive is supplied at an angle of 20-30 degrees;
it is necessary to use small amounts of current;
the connection should be carried out in stages : the performer welds a small section of 2-3 cm and forges the deposited metal so that
avoid residual stress. Forging is done with a small hammer, the weight of which does not exceed 1.2 kg, the hammer is of a rounded type.
Cooling of the part after welding is carried out gradually .

This method is not the main one when connecting cast iron products. This is due to certain difficulties that arise during the work process, as well as an increased level of labor and financial costs.

Equipment and consumables

To obtain good joints from difficult-to-weld alloys, any semi-automatic machines are used. The main criteria are compliance with the maximum current of the device required to penetrate a specific thickness of metal. The adjustable current and wire feed speed parameters are similar to welding conventional steel.

Wire is used with specialized markings: PP ANCH-1, as well as with numbers 2 and 3. Each number is intended for a specific method (cold, semi-hot, hot). The wire has a tubular structure and contains flux powder inside, which protects the weld pool from exposure to oxygen. Enrichment of the applied metal with special impurities promotes high tensile strength of the seam and tensile strength. Thanks to Anch wire, it is possible not only to eliminate minor defects in cast iron, but also to produce full-fledged seams that firmly connect this specific metal.

To weld cast iron, a gas supply is used, which additionally protects the weld pool. Depending on the purpose of the product and the amount of impurities in the alloy, you can use carbon dioxide in its pure form or its mixture with argon, where the latter will be 80%. The flow rate from the pressure gauge to the burner should be 6-11 liters. This will optimally protect the molten metal from displacing carbon.

Semi-automatic welding technology

When welding cast iron with a semi-automatic machine, regardless of the temperature conditions, it is necessary to properly prepare the material. If you need to weld a crack, it is important to make a preliminary cut with a grinder along the entire split line. This will allow the filler material to be fused deeper. It is recommended to drill the edges of the cracks to limit its continuation.

If the thickness of the plates is more than 5 mm, then cutting the edges at 45-60 degrees is necessary. When working with thin sheets (up to 3 mm), graphite preforming is used to prevent burns. The first seam is made with a smooth pass without oscillatory movements. The burner can be operated from top to bottom or from right to left, tilted 50 degrees. The distance between the nozzle and the surface is maintained within 6-8 mm. It is important that the welder can see the end of the wire.

It is rarely possible to brew cast iron the first time, so it is recommended to go through the seam in several layers. Subsequent passes can be made with transverse vibrations in order to bind the base and deposit metal more widely. After welding is completed, it is necessary to separate the slag formed during combustion of the flux-cored wire and ensure the quality of the result.

Semi-automatic welding of cast iron is quite popular due to its high productivity and good quality of connections. By choosing the right wire and temperature conditions, you can get a reliable connection on this “capricious” material.

Preparing cast iron for cold welding with an inverter

Before welding cast iron, it must be prepared. First, the desired area is cleaned with a grinder with a flap wheel or other suitable attachment. After stripping the top layer to non-oxidized metal, it is necessary to carry out mandatory degreasing with gasoline or any other solvent. If you decide to repair the crack, then you need to clear the metal until it ends, and drill a hole with a diameter of 10 mm in this place.

It is worth talking separately about the following preparation features:

1. Hairpins. Arc welding of cast iron can be carried out either layer by layer without the use of supporting elements, or using studs. The studs are made of steel. Their dimensions are strictly regulated, for example, the diameter should not exceed 40% of the thickness of the cast iron. The protrusion of the stud above the metal is limited to 4-6 mm, and the distance between the studs should not be more than 6 diameters. The amount depends only on the size of the connection, but not more than 25% of the fracture area

2. Cutting edges.

Note! The edges should not have a sharp cut at the junction of two parts of metal; the optimal shape is spherical.

3. Electrodes must be special. It is almost impossible to weld such metal with conventional electrodes on steel, so it is worth purchasing an electrode with the addition of copper, chromium, nickel and other alloys that facilitate welding onto fastidious cast iron.