Basic classification of welds for different types of welding

A weld is a section where two parts are joined into a single whole due to the melting of the metal under the influence of high temperature and its further crystallization. Today, more than 100 types of connections are distinguished. They are all divided according to special parameters and divided into various groups and subgroups, and therefore there are many classifications of welds.

According to the type of welded joint

The classification of welds according to the type of welded joint is divided into butt and corner. The master decides which connection to make in a given situation, based on the position of the parts in space.

Corner welds are made when the workpieces are at an angle to each other.
Welding of butt joints is formed as a result of the adjacency of two parts or parts with their ends facing each other, which are located on the same plane. The track itself can be of three types - concave, convex or flat. The latter is used most often, since it does not have a particularly pronounced transition at the junction of parts, which looks more natural in comparison with the other two types. This method is most often used when electric arc welding at low currents, so as not to scorch the workpiece. For example, sheet steel is an ideal material for butt welding applications.
Slotted (electric rivet) is made in the hole that is on the part and is made in the form of spot rivets. That is, in this case, a weld pool and a seam are not formed as a result, and the parts are soldered in small sections through grooves in the workpiece.

How to tie a knot correctly

In order for surgical sutures to provide reliable fastening, you must be able to tie a surgical knot.

The technique can be manual or instrumental. The manual method is used for many operations. Instrumental is used in microsurgery (for example, during surgery on the organs of vision), when performing specialized operations, as well as with difficult access to the surgical wound. Often the instrumental method of tying knots is used when performing operations on blood vessels.

Surgical nodes are:

consisting of 1 loop;
consisting of 2 loops;
consisting of 3 loops.

A single-loop surgical knot is used for short-term tissue fixation. Other types of knots are used for long-term or permanent fixation of tissues.

Each of these types has its own characteristics and tying techniques.

Features of the surgical unit:

The 1st knot is carefully tightened to the limit;
The 2nd one fixes the first node;
The 3rd is used for additional fixation.

Some surgical procedures require one additional turn of the knot.

Method of tying a surgical suture:

fixing the end of the thread with your fingers;
cross the surgical material (grab the right one with your left hand, place the left part in your right hand);
the place where the threads cross is grasped with the thumb and index finger of the left hand;
the ends of the ligature in the right hand are pulled up as much as possible and brought together under the index finger of the left hand;
turn the left hand, with a nodding movement of the index finger, the ligature is passed into the gap and securely fixed.

After the manipulation, long pieces of suture material may remain. They need to be shortened as much as possible, since the presence of foreign parts in the area of the surgical wound can lead to the formation of inflammation.

In order to make the suture as safe as possible for the patient, you must adhere to the following rules:

the threads of suture material must always be in the surgeon’s hand;
the tension of the threads should be optimal, that is, excessive overtension should be avoided;
sew the edges of the wound as carefully as possible to avoid cutting through them (to avoid the formation of bedsores in the suture area);
If there is any doubt about the correctness of the suture, you need to remove it and apply a new one.

Modern methods of wound suturing make it possible to avoid the appearance of scar changes in the tissue area.

At the place of welding

The classification of welded joints and seams in this category depends on the position of the welded parts in space. For example, if you need to repair a part of some kind of structure that cannot be removed and put down, but it is located at some distance from the floor, then the master will carry out the work using a ceiling, bottom, horizontal or vertical connection, starting from the placement of this part.

Horizontal are welds that extend from left to right (or vice versa) on a vertical part. To prevent the mass of metal from flowing down, it is necessary to correctly select the speed of movement of the electrode or torch and the current strength (this is selected for each case individually, based on the type of welding, the characteristics of the parts and the skill of the specialist).
The vertical method of producing butt welds is carried out on vertically positioned workpieces, with the seams being made from top to bottom (or vice versa). The complexity of this process lies in the fact that the force of gravity of the Earth is triggered and the molten metal mass flows down all the time, which spoils both the quality and appearance of the part. Such connections are recommended to be carried out in extreme cases and only to those craftsmen who already have a certain theoretical and practical knowledge for working with such paths. More information about vertical seam technology can be found here.
Ceiling is a position in which the part is located above the master’s head, which greatly complicates the process. When making ceiling welds, you must strictly follow safety rules and welding technology, because in this case the danger lies in the flow of molten metal.
Lower welding methods are performed when the part is located below in relation to the master. This is the most convenient connection method, since the metal does not spread to the sides or down, but flows into the crater. In addition, gases and slags freely escape to the surface. A butt welded joint in the lower position is performed by forming beads throughout the entire joint of the parts. At the same time, the welding technology is simple - it is enough to move the electrode or torch straight or in a zigzag to create a reliable and aesthetically attractive path.

Classification of machine seams

We must move on to the classification of machine seams , and this is where an ambush awaits us!

There are two types of classification of thread seams: according to GOST and according to purpose.

We read:

“ The classification of seams by purpose is used to select the processing of cuts and parts, when describing the manufacturing technology of a model, and to unambiguously define a seam in a business conversation between

But there is no such classification in GOST! And there is a classification consisting of 8 classes in accordance with the international classification, which places all the seams not according to their intended purpose, but based on the location of the layers of materials being joined. And in these classes, all the seams known to us are not located at all in the order in which we were taught, we taught and are still teaching our children and grandchildren. (Textbook of technology for girls, edited by Simonenko § 22, “Machine seams”).

seam designations technology grade 5

machine stitch patterns for comparison

I wrote this article almost a week ago. I have known the material for more than thirty years, I removed a roller along the connecting seams, and prepared another one along the remaining machine seams. Everything is fine. As a teacher, I have a technology manual on this topic: a serious article “Machine thread seams and their application” in the professional magazine “School and Production” with reference to GOST 12807-79 “Sewing products. Classification of stitches, lines and seams." The article says (verbatim):

“In accordance with GOST ... machine thread seams, according to their purpose and the location of the parts being connected, are divided into connecting, edge and finishing.”

I personally have never seen an official document - a real GOST, in addition, during all the time I have been working, I have never seen any of my colleagues have anything different from what I know and what is written here. Also, the entire space of the “sewing” Internet contains the same information. That is, everyone gives the same classification of seams - according to their intended purpose.

Since I would like to maintain my website at a high enough level so that subscribers and visitors can trust me, I decided to correct the GOST date, thinking that there had already been a reissue over the years. I found GOST on the official standardization website and was shocked.

Already in 1988, there was a reissue of GOST, in which classes appear and there is not a word about the three categories of seams according to their intended purpose. In 2003, a new edition of GOST was published and there were the same classes and again not a word about the three groups of seams for their intended purpose. GOST for 1979 has already been deleted and I can’t find out now what was written there? Where did this classification by purpose come from, who came up with these three categories? The worst thing is that the seams that are indicated in the classes do not at all coincide with the types of seams found in the groups. And what is truer, what is more correct, what is more legal? In accordance with what regulatory document should seams be divided according to their intended purpose?

In the old GOST it is written both “by purpose” and by “location” of the seams. In the new GOST we read:

“The main classification feature of the materials being joined is the arrangement of the layers.”

And the most interesting thing is that all the seams in the GOST classification (and there are more than two hundred of them) are called “stitched”, when, according to the accepted division into three groups, only four seams are classified as stitched!

Table 2.1 of GOST 12807-, 2003... is called

table 2.1 GOST

In GoST there are different seams: edging, overhead, finishing and so on, but note that they are not talking about machine seams, but about stitched seams. ????

For two days after this unpleasant discovery, I was simply sick and could not do anything. Then I began to study, analyze, trying to understand the logic of the unification. It’s not for nothing that they say: teaching a scientist only spoils him. The revolution is not only in the brain, but also in the understanding that what I was confident in for so many years has collapsed. There are more than two hundred seams in total, including seams that were not considered before. And now, having gathered my thoughts, I am writing the article again. I’m still in a trance state, but already with an established scheme for seeing the problem.

Why such passions, you say? What difference does it make what seams are located where? Once upon a time in the sixties, in the sewing circles of the Houses of Culture, “grandmothers” carried out cutting according to measurements: POT, POB, and so on. This is how measurements were once designated. When I came to study, we already had designations: St., Sat. and so on. The sites are run by all my peers - students of those distant sixties - now also grandmothers. And the textbooks are not only written by “grandmothers”, but also not sewing specialists at all (judging by various signs). The teachers are also the same “grandmothers” - all my peers, only still working. Some kind of “general society of grandmothers” who are stuck in the past and are in no hurry to catch up with time, or rather, do not correspond.

Of course, you can sew the same dresses with both POT and ST. And in this topic, if you close your eyes to GOST, then you can simply sew something, call something somehow. And everything will work out. You can not speak at all and sew well too. But people search on the Internet for “types of machine seams”, “classification of machine seams”, some even using the old concepts of “connecting seams” - people want to know! And there are about 160 more requests “ GOST sewing seams” . Therefore, I can no longer speak as before. I will have to speak not only in the old way, but also in the new way. You have the right to choose.

By length

Classification of welds by length is of two types: continuous or intermittent.

Intermittent is a seam that is made of a certain length with a synchronous interval. It, in turn, is divided into two types - chain track and checkerboard seam. For example, double-sided intermittent joints on one side of the wall are located opposite the welded sections of the seam on the other side. These types of coupling can be either one-way or two-way. That is, the part is soldered on both sides. The distance between these welded sections is called the “welding pitch”.
Continuous welding methods are also divided into short and long tracks, and are performed along the entire workpiece.
The spot method of butt welds differs significantly from others, due to the fact that there is no weld pool and track. In this case, the workpieces are connected at points using an overlap weld. This method is often used for soldering thin metal or batteries.

Methods of extended seams: a) continuous b) intermittent, c) point, d) intermittent checkerboard, e) intermittent continuous (chain)

Butt seam

Used for joining parts made of cushioning fabrics where a minimum seam thickness is required. To make the seam, we cut out an additional strip of cotton fabric with a width of at least 20 mm and a length equal to the length of the parts being joined. We place the sections of the parts end-to-end on a strip of fabric and adjust them onto the strip at a distance of 5 mm from the sections. We connect the sections with a zigzag machine stitch.

According to execution technology

Depending on the technology used for fastening, there are four main types:

The underwelding, where - the smaller part of the double-sided seam, is performed in advance to prevent burn-throughs during subsequent welding;
a tack weld allows you to fix parts that are already positioned for welding;
a temporary seam is necessary to hold the workpieces together for a while, and upon completion of the work it is removed.
installation weld, used during installation of various structures.

In relation to the direction of current efforts

Butt welding contains another important classification, depending on the relationship to the direction of force:

Longitudinal method of creating a joint (flank), in which the force acts parallel to the axis of the track;
Transverse method (frontal) of the weld, in which its axis is perpendicular (90 degrees) to the axis of force;
A combined welding connection includes both flank and transverse types;
Oblique, in which the axis of the seam is located at an angle to the direction of the acting forces.

According to the shape of the outer surface

According to the shape of the clutch surface, they are divided into three main types:

Convex (reinforced) are multi-layer seams used in clutches under static loads, but increased influx leads to excessive consumption of electrode metal and therefore an economic justification is required for its use.
Concave (loose) methods are used to hold thin metal together.
Normal or flat are relevant for dynamic loads, since they do not have a special difference between the track and the base metal.

By type of welding

The classification of welds by type of welding is divided depending on the type of impact of the welding machine. For example, when working in an environment of argon or other protective gas, the connection will be nothing other than “gas”; when working with an electrode, it will be “electric arc”. The most basic types are the following seams:

manual arc welding - butt or lap joints are made manually using an electrode. Thus, it is possible to fasten almost any metal with a thickness from 0.1 to 100 mm in any position;
automatic welding, which is carried out when working with a device - a transformer, rectifier or inverter;
welding in inert gas. Such butt, corner and lap joints are considered the most durable, since welding occurs in an environment of inert gases, which protect it from oxidation. The big advantage of such fastening is the aesthetic appearance and the absence of waste and slag;
gas welding - the track is formed under the influence of temperature, which is created due to the combustion of the working gas emanating from the torch;
solder connections that are made using a soldering iron.

In addition to those described, there are many more methods for connecting parts, both conventional and non-standard, which are used for welding parts in hard-to-reach places. For example, seams can be single-layer (a) or multi-layer (b, c), in which several rollers are applied, located at the same level of the cross-section of the seam.

Compliance with the laws of asepsis and antisepsis when applying sutures

Asepsis and antisepsis in surgical practice are of great importance. Asepsis consists of carrying out a set of measures aimed at preventing the entry of microbes into the wound. Antiseptics are measures aimed at destroying microorganisms in a wound.

Careful adherence to asepsis and antisepsis significantly reduces the risk of developing bacterial complications in the wound, improves the prognosis for the recovery and life of the patient, and also shortens the recovery process after injury.

Primary surgical treatment is carried out at the stage of first aid. It consists of removing foreign bodies in the wound (if this does not threaten the development of bleeding), stopping the bleeding, and draining the wound.

Before suturing, the wound is cleaned and then treated with a 60% alcohol solution. After which they are treated with iodine again. Then the surgical field is limited using sterile sheets.

During the initial cleansing of the wound, the instruments are constantly changed so that no infection gets into the wound. After this, nonviable tissue is excised, the cavity is drained, and antibiotics are administered. All manipulations are carried out in a sterile operating room using sterile instruments.

After suturing, the surgical area must be cleaned and secured with a sterile swab or bandage. It is also possible to install drainage, with the help of which accumulated fluid, blood or purulent discharge drains from the wound.