Dural: production technology and application

Aluminum is a light silver metal. It is light, relatively soft, and melts at a temperature of 660.4°C. Al easily dissolves in strong alkalis and is resistant to acids, since a protective film is formed on its surface. Finely crushed metal burns in air when heated. The smaller its particles, the lower the heating temperature is needed for combustion. Aluminum has high thermal and electrical conductivity. This metal is very ductile. This property allows it to be rolled into very thin foil. It also has low strength: pure aluminum can be easily cut with a knife. This metal is very resistant to corrosion - a thin film is formed on the surface of Al, protecting it from destruction.

Depending on the amount of impurities - the purity of the metal - in accordance with GOST, aluminum is assigned a certain grade.

How to distinguish aluminum from stainless steel: features, characteristics, production methods, application

We welcome everyone who, being a real owner, draws knowledge and experience from our site. This suggests that today for some reason you are interested in the question of how to distinguish aluminum from stainless steel. But really, it’s not that simple.

Features of aluminum

Why is aluminum so valuable? This is a pure metal classified as non-ferrous. It is lightweight, durable, has a good degree of deformation, and is resistant to aggressive environments and corrosion.

All of the listed advantages allow it to be used in a variety of areas from industry and construction (except for industries where high-strength structures are manufactured) to domestic use.

The demand for the valuable metal is great, so it is important to know how to accurately distinguish it from other similar metal alloys.

Aluminum or stainless steel: methods of determination

There are several ways to help you do simple research on your own at home. Find out how to distinguish aluminum from stainless steel - advice from forum members and experts.

1. Using a magnet. Aluminum of any grade will not stick to a magnet. Stainless steel also has this property. But there is an exception to the rule. If it contains nickel in sufficient quantities, the tested products will have some attraction. If there is a lot of chromium or copper in a stainless metal, it will not have any effect on the magnet.
2. Marking on stainless steel. Some stainless steel products have identification markings. This already gives a hint on how to distinguish aluminum from stainless steel. If there are markings, for example, “STAINLESS” and the like, this is not aluminum.
3. Plain paper won't lie. The method is very simple. Experiment conditions: you need white, as thick paper as possible (printer paper will also work). Use a thick cloth to remove dirt from the edges of the products being tested. Move the cleaned areas one by one with some pressure across the sheet. There will be no traces left of the stainless steel. Aluminum will draw gray stripes.
4. How to distinguish aluminum from stainless steel by the color of the metal? The surface of the object has a shiny, colorless hue that does not change over time - it is stainless steel. The matte surface of a product that has a grayish or whitish color is aluminum. It will not be polished with sandpaper to a high gloss finish. Check it out.
5. Under mechanical load. Another simple way will help you understand how to distinguish aluminum from stainless steel. Hit the product against the surface of any hard metal in the dark. Aluminum will never spark, unlike stainless steel.
6. Thermal conductivity, melting. Compare where the water heats up faster. Of course, in an aluminum container. This metal has much better thermal conductivity. But it is not used on the burner of a gas furnace; the melting point is 660 °C. Stainless steel cannot be melted in the usual way (melting index is above 1800 °C).
7. Testing for copper sulfate. An option available to everyone. Copper sulfate, after exposure to aluminum, will leave cloudy stains and traces on it, but will not appear on stainless steel.
8. Alkaline solutions. Any housewife knows that it is impossible to boil aluminum cookware in alkaline solutions. It will darken and lose its appearance. Conclusion: aluminum products are afraid of alkali, both sodium and potassium. The same cannot be said about stainless steel.
9. Acid test. All acids, starting with the usual citric acid and ending with more aggressive ones, will leave marks when they get on the aluminum surface. You won’t see them on stainless steel; it doesn’t react with acids.

Duralumin – an alloy of aluminum with transition metals

The industry is not able to provide itself only with pure metal, and duralumin comes to the rescue here - various combinations of manganese, copper and magnesium in an alloy with aluminum.

In addition to all the above properties of its older brother, the transition metal has:

• high degree of strength;
• long service life;
• plasticity;
• high hardness.

It accumulates fatigue properties more slowly and is resistant to cracking.

The disadvantage of products made of duralumin is susceptibility to corrosion, which can be prevented by anodizing, applying a thin layer of paints and varnishes, aluminum.

The choice between the two metals depends on the end use. We pay tribute to their advantages, but also foresee their disadvantages. The domestic sector leaves the choice to aluminum, while the industrial sector votes for the strength that duralumin has.

Naturally, the question arises of how to distinguish aluminum from duralumin. It is almost impossible to determine by eye which metal is which. The chemical laboratory will give you the exact answer. But experts on the forums have their own opinion on this matter.

1. Follow the markings.
2. The color of the alloy is steel gray.
3. Scratches leave clear marks.
4. A ringing sound is heard from the impact.
5. During processing, the chips will break without ductility.
6. The structure of the alloy is fine-crystalline.

You can determine the type of material by conducting an experiment. Apply a drop of sodium hydroxide to duralumin and aluminum samples for 10 minutes. After removing the substance, we learn about the metal from the resulting stains: the dark one is duralumin.

If you place a piece of aluminum in an acid with added alkali, it will dissolve, forming a white powdery precipitate. In the experiment with duralumin, blue copper granules will be present.

Unlike aluminum, the main characteristics of the alloy are lack of ductility, brittleness and hardness.

Everything can be learned by comparison; examine the parts of two samples several times, pick them up and compare the weight. Such familiarity will help you subsequently simply recognize metals.

Silumin - a twofold relationship

Products made from silumin, an aluminum-based alloy with the addition of silicon, literally flooded the market. Why does it attract the buyer and how to distinguish aluminum from silumin?

Advantages of silumin

Of course, this alloy of two materials has its “fans”. They call the following positive features of silumin:

• light in weight;
• highly durable;
• resistant to wear and corrosion;
• cheap price.

Silumin products should be treated with caution, unlike aluminum ones. in silumin, aluminum production waste, silumin-containing alloys, and metal powder do not have an exact proportion. It cannot be called high quality, since the manufacturer produces cheap products under the name of some brand.

The disadvantages of the alloy include:

• design flaws;
• they are unsuitable for food products;
• dangerous to health.

You can distinguish silumin from aluminum visually. The products have a glossy smooth gray surface.

Today, public dissatisfaction with plumbing products continues to grow due to the heterogeneous structure of the material with numerous internal stresses and voids. After 3-5 months, the water tap turns into dust, and the rotary steel ball rusts.

Bimetal and aluminum using radiators as an example

When replacing heating radiators, many are faced with the choice of which material to choose for the new design. Cast iron batteries are a thing of the past; manufacturers offer aluminum, steel and bimetallic ones.

While steel is easily recognizable in appearance, the problem with aluminum and bimetallic structures is that you can’t tell the difference by eye. Moreover, the latter option is in greatest demand.

In the store there is a chance not to buy a fake, but how to distinguish bimetal from aluminum at the market?

Visual recognition will not provide accurate results to the consumer. Both the aluminum and bimetallic systems have external fins made of aluminum. And it’s impossible to visually determine the weight of one section.

For reference: the aluminum section weighs 1–1.6 kg, the bimetallic radiator “compartment” weighs 1.5–2 kg.

You can use the “old-fashioned” method and arm yourself with a neodymium magnet, which has greater power.

Preliminary test. Place the magnet first on the steel, then on the aluminum radiator. The magnetic tester will attract the first option to the surface. The effect will be weaker for a bimetallic radiator. Its steel tubes are located under a diamagnetic material - aluminum. With a powerful neodymium magnet, it is possible to catch the attraction.

It is more difficult when the coolant tubes are made of copper, which, like aluminum, is impervious to the magnetic field.

Difference from other non-ferrous metals

It is known that metals have largely identical properties. But each element has its own distinctive characteristics. They allow you to understand how to distinguish metal from aluminum:

• copper is recognized by its bright reddish hue;
• iron and its alloys have high magnetic properties;
• You can recognize gold by its yellow color;
• Lead has high fragility and density;
• silver has a bright shine;
• Tin has high ductility.

The above methods are only estimates and approximate. More reliable information is available on the pages of special reference literature.

How to distinguish aluminum from duralumin?

Duralumin is a material created on the basis of pure aluminum with alloying elements, the inclusion of which in the composition of the melt changes the properties of the metal. Soft and lightweight aluminum provides load-bearing strength while maintaining all the benefits of a pure element.

Accidental discovery

Duralumin is an alloy of aluminum with a small amount of copper, which is aged at a certain temperature under artificially created conditions. The material was invented in 1903 by Alfred Wilm, who served as an engineer at a German factory.

During the experiments, he noticed a pattern, confirmed through long-term experiments.

He found out that if aluminum and 4% copper are alloyed, and then the resulting material is quenched at a temperature of +500°C, followed by sudden cooling and holding at room temperature for several days, the result is a metal with increased strength, while fully maintaining its ductile properties main element.

Over the following years, alloys were produced with a large number of additives, which increased the strength of the material. At the present stage, duralumin is a high-strength alloy, which, depending on the type, may include copper, magnesium, silicon, zinc, etc.

Compound

The strength properties of duralumin demonstrate high values ​​- up to 370 MPa (the strength of pure aluminum is 70-80 MPa), which makes the material in demand in many areas of industry. An alloy of aluminum with chemical elements, in certain proportions, varies the characteristics of the resulting material. The base alloy consists of classic proportions of ingredients.

Duralumin composition has the following:

• Copper (Cu) - 0.5% of the total mass.
• Manganese (Mn) makes up 0.5% of the alloy.
• Magnesium (Mg) - 1.5% of the total mass.
• Silicon (Si) - 1.2%.
• Iron (Fe) makes up about 0.1% of the composition.
• Aluminum (Al) is the main element.

Main types of alloys

There are several types of alloys that differ in their characteristics.

What can duralumin be like (composition, alloys and qualities)?

• Aluminum + manganese (Al+ Mg), aluminum + magnesium (Al+ Mn), the second name is “magnalia” - characterized by resistance to corrosion, high soldering and welding performance. Difficult to cut. Alloys of these compositions are not subjected to additional hardening. The material is used for the manufacture of gas pipeline pipes, car radiators, tanks for various purposes, in construction work, etc.
• Aluminum + manganese + silicon (Al + Mg + Si), the alloy was given the name “avial”. The properties of duralumin of this composition are resistance to corrosion, lightness and strength of welds, and fine grain. Hardening occurs at a temperature of +515–525°C with sharp cooling in water (+20°C) for 10 days. The main scope of application is products used in conditions of high humidity, the manufacture of materials, parts, machines in the aircraft industry, the automotive industry; recently, avial has replaced expensive steel in parts of mobile phones, etc.
• Aluminum + copper + manganese (Al+Cu+Mg), or duralumin, is a structural material, depending on the need to obtain the final properties, the amount of each alloying element may vary. The alloy has found application in aircraft construction, the space industry, for the manufacture of high-speed trains (Sapsan), etc. The disadvantage of the alloy is its corrosion instability. Duralumin sheets require careful anti-corrosion treatment, which is mainly done by applying pure aluminum to the surface.

Duralumin is the main material for aircraft construction and the space industry. The first application for aircraft occurred in 1911 during the construction of airships. In the 21st century, there are more than ten brands of this lightweight and durable material.

For aircraft parts, the D16t grade is most often used, which contains nine metals, for example titanium, nickel, etc., and the alloy consists of copper, silicon, magnesium. The amount of aluminum in the alloy is limited to the standard content - 93%.

Not all duralumin alloys lend themselves well to welding, so many products are made using rivets and other types of fasteners.

The main industrial use of the material was aircraft construction, automotive industry, and machine tool industry.

But not only high technologies use duralumin; for example, a boat for personal use made from this material will last more than 20 years, and with good care and prevention - even longer.

In shipbuilding, not only ship hulls are made from the material, but also a large number of internal hull parts and components. Duralumin pipes, thick-walled and thin-walled, are used everywhere, from housing and communal services to gas pipelines. Rolled sheets are used in building structures.

Advantages and disadvantages

Duralumin is an aluminum-based alloy, which, like any material, has advantages. Among them:

• High static strength.
• Long service life.
• Low vulnerability to destruction.
• Resistant to many aggressive environments, mechanical and temperature influences.
• Adaptability to welding work (aluminum in its pure form reacts poorly to welding seams).
• Numerous areas of application.

There is one significant drawback that duralumin has - it is susceptible to corrosion. All products made from this material must be clad with pure aluminum or coated with primers that prevent rust.

Prices

Purchasing the material is not difficult; the cost is determined depending on the component composition. Most factories producing non-ferrous metals produce duralumin.

The price depends on many factors, in particular the type of product, volume of delivery and other conditions.

In the accompanying documents, the manufacturer is required to indicate data on the percentage of the alloy, compliance with GOST, and operational characteristics.

The cost of duralumin products (angle, pipe, sheet) starts from 580 rubles per kilogram. With an increase in supply volume, the price per ton of alloy pipes is about 510 thousand rubles. Duralumin circles start at 250 rubles per kilogram. Circle is a symbol for a piece of material, the cross-section of which is a circle of various sizes, the length of the product reaches 3 meters.

How to distinguish aluminum from stainless steel: features, characteristics, production methods, application

We welcome everyone who, being a real owner, draws knowledge and experience from our site. This suggests that today for some reason you are interested in the question of how to distinguish aluminum from stainless steel. But really, it’s not that simple.

Types of alloys

Based on the final purpose of the product, the alloy composition varies to give the material different technical characteristics.

Depending on the list of technological methods in the production process, the following are distinguished:

• tempered;
• aged;
• anodized duralumin.

Based on additional components and nuances of heat treatment, several types of connections are distinguished:

• duralumin (grades D1, D16) a mixture of aluminum, copper, magnesium with a small addition of manganese;
• an alloy of aluminum with magnesium (or manganese) is called “magnalium”;
• aluminum mixed with magnesium and silicon (“avial”) has good corrosion resistance.

In addition to the main elements used for alloying alloys, the composition of duralumin may contain some impurities. At the same time, silicon and iron are included in the chemical composition of primary aluminum, zinc and copper can get in during the melting of various wastes, a number of other components (titanium, zirconium, beryllium) are introduced specifically to change the technical parameters of the final product.

The presence of iron in the alloy composition entails an increase in brittleness, but when paired with nickel, iron significantly improves the mechanical properties of the material under normal and elevated operating temperatures.

The property of additives to change the performance characteristics of the alloy requires a competent and responsible approach to the selection of components and the production process.

Duralumin rod

What is the difference between duralumin and aluminum - Metalist's Handbook

Duralumin is an alloy consisting of a base in the form of aluminum with copper and additives of other metals. The discovery of the technology for its production occurred at the very beginning of the nineteenth century by an employee of a German metallurgical plant.

After numerous experiments, he found that when copper is added to aluminum in a ratio of 96% to 4%, an alloy is obtained, which, when kept in a room at room temperature, retains the ductility of the main element with an increase in strength indicators.

Duralumin: features

The very name of the alloy comes from the Dural trademark, under which its production was launched. It came into Russian at the beginning of the twentieth century and denotes a whole group of alloys with aluminum as a base. Various forms can be found, for example “duralumin” and “duralumin”.

Areas of application of duralumin

The formula for success of duralumin was simple. The light weight and strength of the new product contributed to its rapid spread. Its first major application was in airship frame structures. He showed himself excellently, and over time he found a place in more and more branches of mechanical engineering.

Aircraft manufacturers appreciated duralumin, and it quickly became the basis of aircraft construction, as well as in the future the main structural material in the production of space technology.

It is used in the production of trains. Duralumin these days can be found even in the kitchen in the form of numerous household items. Duralumin foil is also actively used in which confectionery products are sold.

The alloy is also actively used in construction. Various pipes and sheets are parts of building structures.

Duralumin is also used in the automotive industry, helping engineers reduce the weight of the car and improve the technical performance of the car. Due to its resistance to high temperatures, it can also be used for internal engine mechanisms.

Duralumin tolerates vibration better than steel, which made it possible to use it in drilling operations.

It may be noted that not all duralumin alloys are suitable for welding. For example, in the construction of aircraft, rivets are used to create structures from duralumin parts. They can be made from the same duralumin alloy, only suitable for welding.

Dural: alloy composition

Over time, the composition of the duralumin alloy has been improved, many new types have appeared, their differences both in the composition of impurities and in the method of subsequent processing.

• Al+Cu+Mg. This type is called duralumin. Depending on the concentration of copper and manganese in the alloy, its general properties and characteristics also change. This type does not have additional protection against corrosion, therefore its operation requires an additional coating to protect it from moisture.
• Al+Mg+Si. This type is called "avial". Adding parts of magnesium and silicon to aluminum increased the corrosion resistance of the alloy. To obtain its properties, the alloy undergoes heat treatment at a temperature of about five hundred degrees Celsius and is cooled in water at a temperature of twenty degrees with natural aging for about a day. This treatment allows the alloy to be used in conditions of high humidity and under stress.
• Al+Mg, Al+Mn. This alloy is called "magnalia". No heat treatment is used in its production. Its main advantages are increased resistance to corrosion and good suitability for welding and soldering work.

The composition of duralumin in percentage can be considered using the example of the composition of duralumin alloy D16:

• Al (Aluminum): 91 - 94.7%.
• Cu (Copper): 3.7−4.9%.
• Fe (Iron): 0.5%.
• Si (Silicon): 0.5%.
• Zn (Zinc): 0.25%.
• Mg (Magnesium): 1.1 - 1.8%.
• Cr (Chromium): 0.1%.
• Mn (Manganese): 0.4% – 0.9%.
• Ti (Titanium): 0.15%.

Markings may be added depending on the form of release of the alloy:

• "T" - hardening in natural conditions.
• “T1” - after the artificial aging process.
• “A” - after coating with special varnishes and anodizing.

For example, d16t.

Properties of duralumin

Despite attempts to combat corrosion by adding manganese and magnesium, duralumin is still susceptible to it and is susceptible enough to pay attention to it. Therefore, during operation it is necessary to protect it with some kind of coating. Protection should be as thorough as possible.

Dural is characterized by its low weight and high strength. Because of this, it is used as the main structural material in astronautics and aviation. It is also used in aircraft manufacturing, in the production of high-speed trains and various other areas of mechanical engineering.

The average density of duralumin is 2500−2800 kilograms per cubic meter.

The melting point of duralumin is approximately 650 degrees Celsius.

Duralumin alloy, unlike pure aluminum, is well suited for welding work.

It has high resistance to environmental influences and low vulnerability to destruction.

The emergence of such a light and durable material made it possible to raise mechanical engineering to a new level and construct technical projects that previously seemed impossible.

Duralumin

Duralumin can be used to produce various parts and things. This material got its name from the city in which it was created. The differences between duralumin and aluminum lie in the chemical composition, which affects the main performance qualities. Let us consider the features of this alloy in more detail.

Duralumin

Chemical composition

The appearance of duralumin is associated with a German company located in the city of Duren. The specialists of this company were developing a new alloy and mistakenly mixed previously unused components.

After conducting preliminary tests, they were surprised by the results they were able to achieve, but initially considered them to be erroneous.

After some time, they repeated their experiment and achieved even better results.

Aluminum and duralumin, first of all, differ from each other in their chemical composition. Duralumin has the following composition:

1. 4-5% copper;
2. 93% aluminum;
3. 2-3% of other alloying elements that are added to give the alloy special qualities.

Composition of various grades of duralumin

For a long time, duralumin was produced under normal conditions, which determined the poor quality of the elements. The outbreak of war made this metal strategically important, which led to the search for more effective methods of connecting all components. The result of these studies was the following technological features of the process:

1. Heating is carried out at temperatures up to 500 degrees Celsius.
2. It takes about 3 hours to warm up.
3. Rapid cooling with water or saltpeter is carried out to increase strength.

The composition of duralumin can vary significantly - it all depends on the specifics of the production technology used.

The most common brand D16 has the following chemical composition:

1. The main part of duralumin in all cases is represented by aluminum, which accounts for 90-94% of the total mass.
2. A fairly large amount of copper is added to the composition (3.8-4.9%).
3. A prerequisite is the addition of silicon and iron in equal parts, approximately 0.5%.
4. The composition includes zinc (no more than 2.5%).
5. A fixed amount of magnesium is added - 1.8%.

The remaining components are represented by chromium, manganese, titanium, which are taken at approximately 1%.

The resulting duralumin with a similar chemical composition has a fairly high softness index. That is why D16 is often used as semi-finished products in the production of stampings.

Not only the composition of the duralumin alloy affects the basic technological properties. Together with a specific selection of components, artificial aging technology is used, which consists of hardening. To increase the strength and surface hardness, the alloy is subjected to heat treatment with cooling.

Depending on the chemical composition and the manufacturing method used, the technological properties of duralumin can differ significantly. There is no GOST specification for this metal yet.

Immediately after the appearance of duralumin, it was called the most suitable material for the construction of airships and aircraft.

Among the technological properties, the following points should be noted:

1. Low cost, which is determined by simple production technology. The fact that the components do not need to be heated to extremely high temperatures determines a significant reduction in the cost of the material. The cost is also favorably reflected in the possibility of carrying out production in a normal environment.
2. Light weight. Considering the chemical composition, it can be noted that most of the composition is represented by aluminum. This metal is known for its lightness.
3. High melting points made it possible to use duralumin alloy in the production of various elements of aircraft and other equipment. The melting point of duralumin is about 650 degrees Celsius. At the same time, ordinary aluminum melts at lower temperatures, which leads to a change in the basic technological qualities and deformation of products.
4. The density of duralumin is 2.5 grams per cubic centimeter (for steel there are 8 grams per cubic centimeter). It is this indicator that determines a significant reduction in the weight of manufactured parts. This indicator can vary within a relatively small range, reaching a value of 2.8 grams per cubic centimeter.
5. The static strength of duralumin is quite high, which determines its resistance to single loads. That is why the alloy is used in the manufacture of various critical parts. Conducted research indicates that it is quite difficult to destroy such material.

Price of duralumin per 1 kg

The properties of duralumin make it possible to produce blanks of any configuration from this alloy. Thus, hexagons according to GOST 21488/97 cost around 100-160 rubles. per kilogram. Round fittings up to 230 rub. per kg. Dural price per kg mainly depends on the grade of the alloy and the cross-section of the products. Sheet duralumin 0.5 mm thick costs 300 rubles. per kg. Duralumin pipes have a price of 130 rubles. per kg in Moscow.

The aluminum market is expected to face a shortage by 2022. The Russian aluminum giant United, which accounts for about 5.6% of global production, is reducing exports due to Western sanctions policies. Today, American aluminum buyers are forced to defend the Russian company, rightly fearing a sharp rise in prices for these products. Thus, how much duralumin costs in the future will depend solely on the actions of Western countries.

Round duralumin fittings cost up to 230 rubles. per kg

In order to combat sanctions against Rusal Plc, the relevant ministry launched several projects in 2022 that will contribute to the growth of domestic aluminum consumption. As a result, in Russia it increased by 7.6% in 2022 compared to the previous period, and copper increased by 1.8% over the same period. In 2018, over 200,000 tons of aluminum products worth about 730 million US dollars were imported from Russia.

What is the difference between duralumin and aluminum? — Machine tools, welding, metalworking

Duralumin is an alloy consisting of a base in the form of aluminum with copper and additives of other metals. The discovery of the technology for its production occurred at the very beginning of the nineteenth century by an employee of a German metallurgical plant.

After numerous experiments, he found that when copper is added to aluminum in a ratio of 96% to 4%, an alloy is obtained, which, when kept in a room at room temperature, retains the ductility of the main element with an increase in strength indicators.

Checking for density

This is exactly the case when school knowledge in physics, mathematics and chemistry will be useful in real life. Aluminum can indeed be defined by its density. How to do it:

• Take a graduated cylinder and fill it with water.
• We place a piece of the material being tested in it.
• We calculate the volume - the object will displace some of the water from the graduated cylinder, which will indicate the level on the scale when the material is removed.
• Weighs the piece being tested.
• Now we apply the formula: divide the mass by the volume.

If the result is close to 2.7 grams per milliliter, then we are definitely looking at aluminum.