Shear resistance of AISI 304 steel. Stainless steel grades and their characteristics. Typical Properties in Annealed State

Characteristics of steel grade AISI 304 / SS 304

AISI 304 steel is the most popular grade of stainless steel. Increased demand and widespread use is due to its versatility. AISI 304 steel has high corrosion resistance in aggressive environments, high oxidation resistance and excellent low-temperature properties.

It is worth noting that AISI 304 stainless steel is resistant to the negative effects of water (salt, fresh, tap) and acid solutions in high concentrations (acetic, formic, nitric).

The price of aisi 304 is quite affordable, which is another one of its advantages.

Resistivity of stainless steel

• Properties
• Specifications table

In the modern world, stainless steel is an indispensable material in the production of different types of products. It is used in the food, medical, metallurgical and military industries.

Properties of stainless steel

Today, a material such as stainless steel is quite popular in the production of many industrial and household products. Stainless steel is a material that is made from steel with the addition of certain impurities that slow down or make the process of corrosion on the metal impossible.

The main advantage of stainless steel is that it has a high level of resistance to rust.

Depending on the elements added to the steel, stainless steel can have different external qualities and properties. If there are more or less of any impurities, then the corrosion process will either be impossible at all, or it will appear after a long time of using objects made from this material.

Stainless steel is used for the production of industrial and household equipment, dishes and many other things that are exposed to aggressive environments.

In industrial enterprises, stainless steel is produced by adding elements such as:

• copper,
• nickel,
• chromium,
• manganese.

Depending on what types of steel are produced, the amount of certain elements in stainless steel is determined. Thanks to these substances, steel changes its physical and chemical properties, which makes it possible to use this material for the manufacture of various types of products.

All elements added to steel affect its quality. In order to obtain a material that is resistant to corrosion and has a high level of strength, the following is added:

• molybdenum,
• manganese,
• titanium,
• nickel.

Steel also cannot do without such elements as

• manganese,
• phosphorus,
• sulfur,
• silicon,

which are part of iron ore. They are faithful companions of this material for the production of stainless steel. They have practically no effect on its quality.

Stainless steel itself is a unique material. It not only has a number of advantages, but also excellent external qualities. Its shiny surface allows this material to be used as a decorative finish for buildings and fences. Stainless steel is most often used to create handrails for stairs.

Table. Technical characteristics of stainless steel

Chromium-nickel steelChrome-nickel-molybdenumHeat-resistantChromeMechanical properties at 20 degreesMechanical properties when heatedThermal treatmentOther properties

Carbon steels

Carbon steels at room temperature, as already mentioned, have low electrical resistivity due to their high iron content. At 20°C, the value of their resistivity is in the range from 13·10-8 (for 08KP steel) to 20·10-8 Ohm·m (for U12).

When heated to temperatures above 1000°C, the ability of carbon steels to conduct electric current is greatly reduced. The resistance value increases by an order of magnitude and can reach a value of 130·10-8 Ohm·m.

Specific electrical resistance of carbon steels ρe·108, Ohm·mTemperature, °SSteel 08KPsteel 08Steel 20Steel 40Steel U8Steel U12

Low alloy steels

Low alloy steels are able to resist the passage of electricity slightly more than carbon steels. Their electrical resistivity is (20...43)·10-8 Ohm·m at room temperature.

It should be noted that steel grades of this type are the worst conductors of electric current - these are 18Х2Н4ВА and 50С2Г. However, at high temperatures, the ability to conduct electric current among the steels listed in the table practically does not differ.

Electrical resistivity of low-alloy steels ρe·108, Ohm·mSteel grade 2010030050070090011001300

High alloy steels

High-alloy steels have electrical resistivity several times higher than carbon and low-alloy steels. According to the table, it can be seen that at a temperature of 20°C its value is (30...86)·10-8 Ohm·m.

At a temperature of 1300°C, the resistance of high- and low-alloy steels becomes almost the same and does not exceed 131·10-8 Ohm·m.

Electrical resistivity of high-alloy steels ρe·108, Ohm·mSteel grade 2010030050070090011001300

Chromium stainless steels

Chromium stainless steels have a high concentration of chromium atoms, which increases their resistivity - the electrical conductivity of such stainless steel is not high. At normal temperatures, its resistance is (50...60)·10-8 Ohm·m.

Electrical resistivity of chromium stainless steels ρe·108, Ohm·mSteel grade 2010030050070090011001300

Chromium-nickel austenitic steels

Chromium-nickel austenitic steels are also stainless, but due to the addition of nickel they have a resistivity almost one and a half times higher than that of chromium steels - it reaches a value of (70...90)·10-8 Ohm·m.

Electrical resistivity of chromium-nickel stainless steels ρe·108, Ohm·mSteel grade 201003005007009001100

Heat-resistant and heat-resistant steels

In terms of their electrical conductive properties, heat-resistant and heat-resistant steels are close to chromium-nickel steels. The high content of chromium and nickel in these alloys does not allow them to conduct electric current, like ordinary carbon alloys with a high concentration of iron.

The significant electrical resistivity and high operating temperature of such steels make it possible to use them as working elements of electric heaters. In particular, steel 20Х23Н18 in its resistance and heat resistance in some cases can replace such a popular alloy for heaters as nichrome Х20Н80.

Specific electrical resistance of heat-resistant and heat-resistant steels ρе·108, Ohm·mTemperature, °С15Х25Т (EI439)15Х28 (ЭИ349)40Х9С2 (ЭИХ8)Х25С3Н (ЭИ261)20Х23Н18 (ЭИ 417)Х20Н35

Chemical composition in % of AISI 304 steel

SS304 stainless steel is alloyed with nickel, manganese, copper and chromium, which provides it with an austenitic structure, increased strength and resistance in corrosive environments. Short designation AISI 304 – 18 Cr-8 Ni

.

Copper resistivity

> Theory > Copper resistivity

One of the most common metals for making wires is copper. Its electrical resistance is the lowest among affordable metals. It is less only for precious metals (silver and gold) and depends on various factors.

Formula for calculating conductor resistance

What is electric current

At different poles of a battery or other current source there are opposite electric charge carriers. If they are connected to a conductor, charge carriers begin to move from one pole of the voltage source to the other. These carriers in liquids are ions, and in metals they are free electrons.

Definition. Electric current is the directed movement of charged particles.

Resistivity

Electrical resistivity is a value that determines the electrical resistance of a reference sample of a material. The Greek letter “p” is used to denote this quantity. Formula for calculation:

p=(R*S)/l.

This value is measured in Ohm*m. You can find it in reference books, in resistivity tables or on the Internet.

Free electrons move through the metal within the crystal lattice. Three factors influence the resistance to this movement and the resistivity of the conductor:

• Material. Different metals have different atomic densities and numbers of free electrons;
• Impurities. In pure metals the crystal lattice is more ordered, therefore the resistance is lower than in alloys;
• Temperature. Atoms are not stationary in their places, but vibrate. The higher the temperature, the greater the amplitude of vibrations, which interferes with the movement of electrons, and the higher the resistance.

In the following figure you can see a table of the resistivity of metals.

Metal resistivity

Interesting. There are alloys whose electrical resistance drops when heated or does not change.

Conductivity and electrical resistance

Since cable dimensions are measured in meters (length) and mm² (section), the electrical resistivity has the dimension Ohm mm²/m. Knowing the dimensions of the cable, its resistance is calculated using the formula:

R=(p*l)/S.

In addition to electrical resistance, some formulas use the concept of “conductivity”. This is the reciprocal of resistance. It is designated “g” and is calculated using the formula:

g=1/R.

Conductivity of liquids

The conductivity of liquids is different from the conductivity of metals. The charge carriers in them are ions. Their number and electrical conductivity increase when heated, so the power of the electrode boiler increases several times when heated from 20 to 100 degrees.

Interesting. Distilled water is an insulator. Dissolved impurities give it conductivity.

Electrical resistance of wires

The most common metals for making wires are copper and aluminum. Aluminum has a higher resistance, but is cheaper than copper. The resistivity of copper is lower, so the wire cross-section can be chosen smaller. In addition, it is stronger, and flexible stranded wires are made from this metal.

The following table shows the electrical resistivity of metals at 20 degrees. In order to determine it at other temperatures, the value from the table must be multiplied by a correction factor, different for each metal. You can find out this coefficient from the relevant reference books or using an online calculator.

Selection of cable cross-section

Copper wire resistance

Because a wire has resistance, when electric current passes through it, heat is generated and a voltage drop occurs. Both of these factors must be taken into account when choosing cable cross-sections.

Selection by permissible heating

When current flows in a wire, energy is released. Its quantity can be calculated using the electric power formula:

P=I²*R.

In a copper wire with a cross section of 2.5 mm² and a length of 10 meters R = 10 * 0.0074 = 0.074 Ohm. At a current of 30A P=30²*0.074=66W.

This power heats the conductor and the cable itself. The temperature to which it heats up depends on the installation conditions, the number of cores in the cable and other factors, and the permissible temperature depends on the insulation material. Copper has greater conductivity, so the power output and the required cross-section are lower. It is determined using special tables or using an online calculator.

Table for selecting wire cross-section based on permissible heating

Permissible voltage loss

In addition to heating, when electric current passes through the wires, the voltage near the load decreases. This value can be calculated using Ohm's law:

U=I*R.

Reference. According to PUE standards, it should be no more than 5% or in a 220V network - no more than 11V.

Therefore, the longer the cable, the larger its cross-section should be. You can determine it using tables or using an online calculator. In contrast to the choice of cross-section based on permissible heating, voltage losses do not depend on laying conditions and insulation material.

In a 220V network, voltage is supplied through two wires: phase and neutral, so the calculation is made using double the length of the cable. In the cable from the previous example it will be U=I*R=30A*2*0.074Ohm=4.44V. This is not much, but with a length of 25 meters it turns out to be 11.1V - the maximum permissible value, you will have to increase the cross-section.

Maximum permissible cable length of a given section

Electrical resistance of other metals

Current resistance: formula

In addition to copper and aluminum, other metals and alloys are used in electrical engineering:

• Iron. Steel has a higher resistivity, but is stronger than copper and aluminum. Steel strands are woven into cables designed to be laid through the air. The resistance of iron is too high to transmit electricity, so the core cross-sections are not taken into account when calculating the cross-section. In addition, it is more refractory, and leads are made from it for connecting heaters in high-power electric furnaces;
• Nichrome (an alloy of nickel and chromium) and fechral (iron, chromium and aluminum). They have low conductivity and refractoriness. Wirewound resistors and heaters are made from these alloys;
• Tungsten. Its electrical resistance is high, but it is a refractory metal (3422 °C). It is used to make filaments in electric lamps and electrodes for argon-arc welding;
• Constantan and manganin (copper, nickel and manganese). The resistivity of these conductors does not change with changes in temperature. Used in high-precision devices for the manufacture of resistors;
• Precious metals – gold and silver. They have the highest specific conductivity, but due to their high price, their use is limited.

Inductive reactance

Formulas for calculating the conductivity of wires are valid only in a direct current network or in straight conductors at low frequencies.

Inductive reactance appears in coils and in high-frequency networks, many times higher than usual. In addition, high frequency current only travels along the surface of the wire.

Therefore, it is sometimes coated with a thin layer of silver or Litz wire is used.

Reference. Litz wire is a stranded wire, each core in which is isolated from the rest. This is done to increase surface area and conductivity in high frequency networks.

Copper's resistivity, flexibility, relatively low price and mechanical strength make this metal, along with aluminum, the most common material for making wires.

Performance at elevated temperatures

Corrosion resistance in acidic environments

0

= high degree of protection (corrosion rate does not exceed 100 mm/year);

1

= partial protection (corrosion rate ranges from 100m to 1000 mm/year);

2

= no protection (corrosion rate exceeds 1000 mm/year).

Methods for determining and monitoring strength indicators of metals

The development of metallurgy and other related areas for the production of metal objects is due to the creation of weapons. At first they learned to smelt non-ferrous metals, but the strength of the products was relatively low. Only with the advent of iron and its alloys did the study of their properties begin.

The first swords were made quite heavy to give them hardness and strength. Warriors had to take them in both hands to control them.

Over time, new alloys appeared and production technologies were developed. Light sabers and swords came to replace heavy weapons. At the same time, tools were created.

With the increase in strength characteristics, tools and production methods were improved.

Types of loads

When using metals, different static and dynamic loads are applied. In the theory of strength, it is customary to define the following types of loads.

• Compression - an acting force compresses an object, causing a decrease in length along the direction of application of the load. This deformation is felt by frames, supporting surfaces, racks and a number of other structures that can withstand a certain weight. Bridges and crossings, car and tractor frames, foundations and reinforcement - all these structural elements are under constant compression.

• Tension - the load tends to lengthen the body in a certain direction. Lifting and transport machines and mechanisms experience similar loads when lifting and carrying loads.

• Shear and shear - such loading is observed in the case of forces directed along the same axis towards each other. Connecting elements (bolts, screws, rivets and other hardware) experience this type of load. The design of housings, metal frames, gearboxes and other components of mechanisms and machines necessarily contains connecting parts. The performance of devices depends on their strength.

• Torsion - if a pair of forces acting on an object are located at a certain distance from each other, then a torque occurs. These forces tend to produce torsional deformation. Similar loads are observed in gearboxes; the shafts experience just such a load. It is most often inconsistent in meaning. Over time, the magnitude of the acting forces changes.

• Bending – a load that changes the curvature of objects is considered bending. Bridges, crossbars, consoles, lifting and transport mechanisms and other parts experience similar loading.

In the middle of the 17th century, materials research began simultaneously in several countries. A variety of methods have been proposed for determining strength characteristics. The English researcher Robert Hooke (1660) formulated the main provisions of the law on the elongation of elastic bodies as a result of the application of a load (Hooke's law). The following concepts were also introduced:

1. Stress σ, which in mechanics is measured in the form of a load applied to a certain area (kgf/cm², N/m², Pa).
2. Elastic modulus E, which determines the ability of a solid body to deform under loading (applying force in a given direction). Units of measurement are also defined in kgf/cm² (N/m², Pa).

The formula according to Hooke's law is written as ε = σz/E, where:

• ε – relative elongation;
• σz – normal stress.

Demonstration of Hooke's law for elastic bodies:

From the above dependence, the value of E for a certain material is derived experimentally, E = σz/ε.

The modulus of elasticity is a constant value that characterizes the resistance of a body and its structural material under normal tensile or compressive load.

In the theory of strength, the concept of Young's modulus of elasticity is adopted. This English researcher gave a more specific description of the methods of changing strength indicators under normal loads.

The elastic modulus values ​​for some materials are given in Table 1.

Table 1: Modulus of elasticity for metals and alloys

Elastic modulus for different steel grades

Metallurgists have developed several hundred grades of steel. They have different strength values. Table 2 shows the characteristics for the most common steels.

Table 2: Elasticity of steels

: Hooke's law, modulus of elasticity.

Strength modules

In addition to normal loading, there are other force effects on materials.

The shear modulus G determines the stiffness. This characteristic shows the maximum load value for changing the shape of an object.

The bulk modulus of elasticity K determines the elastic properties of a material to change volume. With any deformation, the shape of the object changes.

Poisson's ratio μ determines the change in the ratio of relative compression to tension. This value depends only on the properties of the material.

For different steels, the values ​​of the indicated modules are given in Table 3.

Table 3: Strength moduli for steels

For other materials, strength characteristics are indicated in specialized literature. However, in some cases individual studies are carried out. Such research is especially relevant for building materials. At enterprises where reinforced concrete products are produced, tests are regularly carried out to determine limit values.

Scope of application AISI 304

Stainless steel AISI 304 (18 Cr-8 Ni), due to its high resistance to oxidation and high temperatures, has found wide application:

• in the chemical and pharmacological industry;
• in the food, dairy and brewing industries;
• in medicine (surgical equipment, injection needles);
• in the production of ship equipment and fasteners for nuclear ships;
• in rolled metal (pipes, angles, sheets, tapes, hexagons);
• in the oil (filter screens for wells) and mining industries;
• in the production of equipment for working under conditions of chemical exposure;
• in the construction of structures for which strength and long service life are important;
• in the textile and paper industry.

In addition, due to its excellent technical parameters, hygienic indicators and pleasant aesthetic appearance, 304 steel is used in the manufacture of kitchen furniture and cutlery; containers for storing liquid and dry substances.

AISI 304 stainless steel is used in the production of cooling coils, cryogenic vessels, refrigeration equipment, sanitary fittings, pressure vessels, etc.

Welding

Stainless steel aisi 304 / SS 304 / 18 Cr-8 Ni is easily welded by all methods. Subsequent heat treatment is only necessary if there is a risk of intergranular corrosion. It is carried out at 1050-1150°C, the seam must be cleaned of the resulting scale and passivated with a special paste.

Modulus of elasticity of steel

►Elasticity modulus of steel ►Elasticity modulus of different steel grades ►Table of strength moduli of steel grades ►Elasticity modulus for metals and alloys ►Elasticity of steels ►Strength limit
When designing steel products or structural elements, the ability of the alloy to withstand multidirectional types of loads is taken into account: impact, bending, tensile, compressive. The value of the elastic modulus of steel, along with hardness and other characteristics, shows resistance to these influences.

For example, in reinforced concrete construction, longitudinal and transverse reinforcing bars are used. In the horizontal plane they are subject to tension, and in the vertical plane they are subject to pressure from the entire mass of the structure.

In places where stress is concentrated: corners, technological openings, elevator shafts and flights of stairs, more reinforcement is placed.

The ability of concrete to absorb water causes constant changes in compressive and tensile loads.

Let's look at another example. During wartime, many developments in the field of aviation were created. The most common causes of accidents were engine fires. Taking off from the ground, the plane enters atmospheric layers with rarefied air and its body expands; the reverse process occurs during landing.

In addition, the structure is affected by the resistance of air flows, the pressure of curved layers of air and other forces. Despite their strength, the alloys existing at that time were not always suitable for the manufacture of critical parts; this mainly led to ruptures of fuel tanks.

In various types of industry, parts of moving mechanisms are made from steel: springs, leaf springs. The grades used for such purposes are not prone to cracking under constantly changing loads.

The elasticity of solids is the ability to return to its original shape after the cessation of deforming influences. For example, a block of plasticine has zero springiness, while rubber products can be compressed and stretched. When various forces are applied to objects and materials, they become deformed. Depending on the physical properties of the body or substance, two types of deformation are distinguished:

• Elastic - the consequences disappear after the action of external forces ends;
• Plastic - irreversible change in shape.

The modulus of elasticity is the name of several physical quantities that characterize the tendency of a solid body to deform elastically.

The concept was first introduced by Thomas Young. The scientist suspended weights from metal rods and observed their elongation. Some samples doubled in length, while others were torn during the experiment.

Today the definition combines a number of properties of physical bodies:

Young's modulus : Calculated by the formula E= σ/ε, where σ is the stress equal to the force divided by the area of ​​its application, and ε is the elastic deformation, equivalent to the ratio of the elongation of the sample from the beginning of deformation and compression after its cessation.

Shear modulus (G or μ) : the ability to resist deformation while maintaining volume when the direction of loads is tangential. For example, when hitting the head of a nail, if it was not made at a right angle, the product becomes distorted. In sopromat, the value is used to calculate shifts and torsion.

Bulk modulus or bulk modulus (K): changes caused by the action of a confining stress, such as hydrostatic pressure.

Punch ratio (Ⅴ or μ) : the ratio of transverse compression to longitudinal elongation, calculated for material samples. For absolutely fragile substances it is zero.

Lamé's constant : the energy that provokes a return to its original form, calculated through the construction of scalar combinations.

The modulus of elasticity of steel is correlated with a number of other physical quantities. For example, when conducting a tensile experiment, it is important to take into account the tensile strength, exceeding which results in destruction of the part.

• Ratio of rigidity and ductility;
• Impact strength;
• Yield strength;
• Relative compression and tension (longitudinal and transverse);
• Strength limits under shock, dynamic and other loads.

The use of a number of approaches is determined by the requirements for the mechanical properties of materials in various industries, construction, and instrument making.

Elastic modulus of different steel grades

Spring steel alloys have the greatest ability to resist deformation. These materials are characterized by high yield strength. The value shows the stress at which the deformation increases without external influences, for example, when bending and twisting.

The elasticity characteristics of steel depend on alloying elements and the structure of the crystal lattice. Carbon imparts hardness to the steel alloy, but in high concentrations it reduces ductility and springiness. The main alloying additives that increase elastic properties: silicon, manganese, nickel, tungsten.

Often, the desired indicators can be achieved only with the help of special heat treatment modes. In this way, all fragments of the part will have uniform fluidity indicators, and weak areas will be eliminated.

Otherwise, the product may break, burst or crack.

Grades 60G and 65G have such characteristics as tensile strength, viscosity, wear resistance, they are used for the manufacture of industrial springs and musical strings.

The metallurgical industry has created several hundred grades of steel with different elastic moduli. The table shows the characteristics of popular alloys.

Table of strength moduli of steel grades

Modulus of elasticity for metals and alloys

Elasticity of steels

Tensile strength

Solids are capable of withstanding limited loads; exceeding the limit leads to destruction of the metal structure, the formation of noticeable chips or microcracks. The occurrence of defects is associated with a decrease in performance properties or complete destruction. The strength of alloys and finished products is checked on test benches. The standards provide for a number of tests:

• Prolonged use of deforming force;
• Short-term and long-term shock impacts;
• Tension and compression;
• Hydraulic pressure, etc.

In complex mechanisms and systems, the failure of one element automatically causes increased loads on others. As a rule, destruction begins in those areas where stress is maximum. The safety margin serves as a guarantee of equipment safety in emergency situations and extends its service life.

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General concept

The modulus of elasticity (also known as Young's modulus) is one of the indicators of the mechanical properties of a material, which characterizes its resistance to tensile deformation. In other words, its value shows the ductility of the material. The greater the elastic modulus, the less any rod will stretch, all other things being equal (load magnitude, cross-sectional area, etc.).

In the theory of elasticity, Young's modulus is denoted by the letter E. It is an integral part of Hooke's law (the law on the deformation of elastic bodies). Connects the stress arising in the material and its deformation.

According to the international standard system of units, it is measured in MPa. But in practice, engineers prefer to use the dimension kgf/cm2.

The elastic modulus is determined experimentally in scientific laboratories. The essence of this method is to tear dumbbell-shaped samples of material using special equipment. Having found out the stress and elongation at which the sample failed, divide these variables by each other, thereby obtaining Young's modulus.

Let us immediately note that this method is used to determine the elastic moduli of plastic materials: steel, copper, etc. Brittle materials - cast iron, concrete - are compressed until cracks appear.

Additional characteristics of mechanical properties

The modulus of elasticity makes it possible to predict the behavior of a material only when working in compression or tension. In the presence of such types of loads as crushing, shear, bending, etc., additional parameters will need to be introduced:

• Stiffness is the product of the elastic modulus and the cross-sectional area of ​​the profile. By the value of rigidity, one can judge the plasticity not of the material, but of the structure as a whole. Measured in kilograms of force.
• Relative longitudinal elongation shows the ratio of the absolute elongation of the sample to the total length of the sample. For example, a certain force was applied to a rod 100 mm long. As a result, it decreased in size by 5 mm. Dividing its elongation (5 mm) by the original length (100 mm) we obtain a relative elongation of 0.05. A variable is a dimensionless quantity. In some cases, for ease of perception, it is converted to percentages.
• Relative transverse elongation is calculated similarly to the point above, but instead of length, the diameter of the rod is considered here. Experiments show that for most materials, transverse elongation is 3-4 times less than longitudinal elongation.
• The Punch ratio is the ratio of the relative longitudinal strain to the relative transverse strain. This parameter allows you to fully describe the change in shape under the influence of load.
• The shear modulus characterizes the elastic properties when the sample is exposed to tangential stresses, i.e., in the case when the force vector is directed at 90 degrees to the surface of the body. Examples of such loads are the work of rivets in shear, nails in crushing, etc. By and large, the shear modulus is associated with such a concept as the viscosity of the material.
• The bulk modulus of elasticity is characterized by a change in the volume of the material for uniform, versatile application of load. It is the ratio of volumetric pressure to volumetric compressive strain. An example of such work is a sample lowered into water, which is subject to liquid pressure over its entire area.

In addition to the above, it should be mentioned that some types of materials have different mechanical properties depending on the direction of loading. Such materials are characterized as anisotropic. Vivid examples are wood, laminated plastics, some types of stone, fabrics, etc.

Isotropic materials have the same mechanical properties and elastic deformation in any direction. These include metals (steel, cast iron, copper, aluminum, etc.), non-laminated plastics, natural stones, concrete, rubber.

Elastic modulus value

It should be noted that Young's modulus is not a constant value. Even for the same material, it can fluctuate depending on the points at which the force is applied.

https://www.youtube.com/watch?v=ZyK3nd4Ndks

Some elastic-plastic materials have a more or less constant modulus of elasticity when working in both compression and tension: copper, aluminum, steel. In other cases, the elasticity may vary based on the shape of the profile.

Here are examples of Young's modulus values ​​(in millions kgscm2) of some materials:

• White cast iron – 1.15.
• Gray cast iron -1.16.
• Brass – 1.01.
• Bronze – 1.00.
• Brick masonry - 0.03.
• Granite stonework - 0.09.
• Concrete – 0.02.
• Wood along the grain – 0.1.
• Wood across the grain – 0.005.
• Aluminum – 0.7.

Let's consider the difference in readings between elastic moduli for steels depending on the grade:

• High quality structural steel (20, 45) – 2.01.
• Standard quality steel (St. 3, St. 6) – 2.00.
• Low alloy steels (30ХГСА, 40Х) – 2.05.
• Stainless steel (12Х18Н10Т) – 2.1.
• Die steel (9ХМФ) – 2.03.
• Spring steel (60С2) – 2.03.
• Bearing steel (ШХ15) – 2.1.

Also, the value of the elastic modulus for steels varies depending on the type of rolled product:

• High strength wire – 2.1.
• Braided rope – 1.9.
• Cable with a metal core - 1.95.

As we can see, the deviations between steels in the values ​​of elastic deformation moduli are small. Therefore, in most engineering calculations, errors can be neglected and the value E = 2.0 taken.

HEAT TREATMENT

The experiment was carried out at high temperatures in the range from 1010°C to 1120°C with further cooling in water or air (quick tempering). According to research, the resistance turned out to be optimal when annealed at a temperature of 1070°C followed by rapid cooling.

Vacation (stress relief)

The studies were carried out for an hour for grade 304L at temperatures of 450–600°C with minimal risk of sensitization. Recommended temperature 400°C (maximum temperature).

1. Initial temperature: 1150–1260°C.
2. Final temperature: 900–925°C.

For any hot processing, the annealing method is used. Particular attention should be paid to the heating time of stainless steel to achieve uniform heating: stainless steel takes approximately 12 times longer to heat up than carbon steels.

COLD WORKING

Due to such qualities as strength, ductility and elasticity, grades 304 and 304L are widely used in cold working. The methods used are stretch molding, bending or rotary and deep drawing.

The forming method uses the same machines and tools as carbon steel, but with more force (50-100%). The reason is that when forming austenitic steel, it is characterized by increased hardening.

Approximate bending limits (s = sheet thickness, r = bending radius):

Classification

Modern stainless wire is made not just from steel with a minimal level of corrosion. It is also always a high-level alloyed material that is resistant to strong heat. The universal long structure is easy to recognize - it looks like a thread or string. Mostly stainless steel wire has a circular cross-section. It is used in a variety of areas, therefore it is represented by a number of modifications.

Knitting wire is very popular. It is used to fix reinforcement - and it is not surprising that this material should not rust during normal use for as long as possible. The basic requirements are stated in GOST 3282-74. Experts have long noted that the thicker the reinforcement, the larger the cross-section of the wire used should be. It must be positioned as evenly as possible, because otherwise the loads will be distributed incorrectly.

But welding wire can also be stainless. This material is valuable because the finished weld also has excellent anti-corrosion properties. Basically, special steel fibers are used for fully or partially automated welding processes. It is useful both for working in an inert gas atmosphere and for welding powdered metal.

Mechanical properties

AISI 304 steel can be easily processed in hot and cold conditions and can be welded well in a variety of ways.

GOST standards and specifications for alloy 06ХН28МДТ

GOST 1133-71 “Forged steel round and square. Assortment”; GOST 25054-81 “Forgings made of corrosion-resistant steels and alloys. General technical conditions.”; GOST 4986-79 “Cold-rolled strip made of corrosion-resistant and heat-resistant steel. Technical conditions”; GOST 5582-75 “Corrosion-resistant, heat-resistant and heat-resistant rolled thin sheets. Technical conditions”; GOST 5632-72 “High-alloy steels and corrosion-resistant, heat-resistant and heat-resistant alloys. Marks”; GOST 5949-75 “Grade and calibrated steel, corrosion-resistant, heat-resistant and heat-resistant. Technical conditions”; GOST 7350-77 “Corrosion-resistant, heat-resistant and heat-resistant thick sheet steel. Technical conditions”; GOST 9940-81 “Hot-deformed seamless pipes made of corrosion-resistant steel. Technical conditions”; GOST 9941-81 “Cold- and heat-deformed seamless pipes made of corrosion-resistant steel. Technical conditions”; TU 14-3-763-78; TU 14-3-822-79; GOST 4405-75 “Hot-rolled and forged strips made of tool steel. Assortment.”; GOST 14955-77 “High-quality round steel with special surface finishing. Technical conditions.”; GOST 2590-2006 “High-rolled hot-rolled round steel products. Assortment.”; GOST 2591-2006 “High-rolled square steel products. Assortment.”; GOST 7417-75 “Calibrated round steel. Assortment.”; GOST 4405-75 “Hot-rolled and forged strips made of tool steel. Assortment.”; GOST 8559-75 “Square calibrated steel. Assortment.”; GOST 8560-78 “Calibrated hexagonal rolled products. Assortment.”; GOST 1133-71 “Forged steel round and square. Assortment.”; GOST 5632-72 “High-alloy steels and corrosion-resistant, heat-resistant and heat-resistant alloys. Marks.”; GOST 103-2006 “High-rolled hot-rolled steel strip. Assortment.”; GOST 5949-75 “Grade and calibrated steel, corrosion-resistant, heat-resistant and heat-resistant. Technical conditions.”; TU 14-11-245-88 “High precision shaped steel profiles. Technical conditions.”; OST 3-1686-90 “Structural steel blanks for mechanical engineering. General technical conditions.”;

Characteristics of the material. Steel 06ХН28МДТ (ЭИ943, AISI 904 L )

Chemical composition in % of material 06ХН28МДТ (ЭИ943) . GOST 5632-72

Mechanical properties of steel 06ХН28МДТ (0Х23Н28М3Д3Т EI943, AISI 904L) at T=20oС

Mechanical properties of steel 06ХН28МДТ (0Х23Н28М3Д3Т EI943, AISI 904L) at low and elevated temperatures (sheet 12.0 mm, hardening from 1050 °C)

Mechanical properties of steel 06ХН28МДТ (0Х23Н28М3Д3Т EI943, AISI 904L) at high temperatures (sheet 16.0 mm, quenched at 1050 °C in water)

Mechanical properties of steel 06ХН28МДТ (0Х23Н28М3Д3Т EI943, AISI 904L) at 20 °С depending on the degree of cold plastic deformation

General characteristics of steel 06ХН28МДТ (0Х23Н28М3Д3Т EI943, AISI 904L)

Analogues of special corrosion-resistant austenitic (super-austenitic stainless steel) steels intended for use in environments subject to highly aggressive wet or high-temperature corrosion, as well as for applications that require a combination of high strength and corrosion resistance

Physical characteristics of steel 06ХН28МДТ (0Х23Н28М3Д3Т EI943, AISI 904L) at T=0-900 degrees Celsius

Analogues[edit | edit code]

Russian analogues of steel: AISI 304 according to GOST - 08Х18Н10, AISI 304L - 03Х18Н11.

Analogs and names of steel: AISI304, AISI 304, T304, 304 T, SUS304, SS304, 304SS, 304 SS, UNS S30400, AMS 5501, AMS 5513, AMS 5560, AMS 5565, AMS 5566, AMS 5567, AMS 5639, A MS 5697 , ASME SA182, ASME SA194 (8), ASME SA213, ASME SA240, ASME SA249, ASME SA312, ASME SA320 (B8), ASME SA358, ASME SA376, ASME SA403, ASME SA409, ASME SA430, ASME SA479, ASME SA688, ASTM A167, ASTM A182, ASTM A193, ASTM A194, ASTM A666, FED QQ-S-763, Milspec MIL-S-5059, SAE 30304, DIN 1.4301, X5CrNi189, BS 304 S 15, EN 58E, PN 86020 (Poland), OH18N9, ISO 4954 X5CrNi189E, ISO 683 / 13 11, 18-8