What is structural steel

Structural steel grades

Structural steel is a specially processed alloy of iron and carbon, which is intended for the production of load-bearing structures in construction and has special physical and mechanical properties. It is designed for long-term operation under high load levels. There are a huge number of grades of structural steel, which are determined by several key indicators.

The most important parameter is the quality of the material, which depends on the phosphorus and sulfur content in the alloy. These elements lead to increased fragility of the metal structure, so their presence should be minimized. Material containing these impurities up to 0.05% is classified as normal quality and is marked “st”.

An alloy with a mass fraction of sulfur and fluorine up to 0.035% is considered high quality and is labeled “steel”. When the content of these elements is up to 0.025%, the steel is called high-quality and is marked with the letter “a” at the end.

And material with an amount of impurities up to 0.015% belongs to the category of especially high quality, as evidenced by the letter “w” at the end of the brand.

Categories of structural steels

Depending on the purpose, all structural steels are divided into three categories: A, B and C. Group A is used in structures whose components are not subject to heat treatment. This allows you to keep all the factory properties of the metal intact.

Category B, on the contrary, is intended for structures to which hot processing will be applied. This brand has a clearly regulated chemical composition, and its final properties depend on the processing method.

Group B steel is manufactured specifically for welding. Its physical and chemical properties ensure the maximum level of connection of structural elements with each other. This classification is extremely strict, so you need to use a specific grade of material only for clearly specified purposes. Otherwise, the result may be much lower than the desired level.

Structural steels are also classified according to the degree of deoxidation. It is determined by the amount of silicon in the alloy. There are three types: mild steels (marked “sp”) - silicon content of at least 0.12%; semi-quiet steels (marked “ps”) - silicon content 0.07-0.12%; boiling steels (marked “kp”) - silicon content up to 0.07%.

The degree of deoxidation affects the weldability of the material, as well as the maximum tolerated mechanical loads. The more silicon in the alloy, the better the quality of the steel. Welding of structural steels is carried out using standard equipment.

This type of material was originally intended for creating connecting structures, so it is quite easy to process.

Preparation of structural steels

The production of carbon structural steel is no different from the production of a standard alloy. The material acquires special properties due to special processing under special conditions.

It is very important to follow all technological procedures at the hardening stage, since the quality of the resulting metal directly depends on this. Heat treatment of structural steels is carried out at temperatures of 550-680 degrees Celsius.

This range provides the greatest wear resistance.

The duration of hardening depends on the size of the part and the marking of the material. After annealing, the structure of structural steel acquires a pearlite-ferrite crystal lattice, which tolerates mechanical loads well. In some cases, special additives are added to the alloy, which give the material special properties. This is necessary for those types of steel that will work in unfavorable conditions or in aggressive environments.

Alloy structural steels are used in the most critical areas of structures. They are used to make heavily loaded parts of production equipment, as well as load-bearing structures of buildings and structures.

For alloying, chromium, nickel and manganese are mainly used, less commonly vanadium and boron. These elements allow the alloy to successfully combat the effects of corrosion and work without problems in conditions of high humidity and strong dynamic loads.

For high-quality alloying, 12-15% of the additive in the total mass fraction of the alloy is required.

Low alloy structural steels are more common because they are cheaper to produce. Adding a small amount of an alloying element will allow the material to be successfully used outdoors without fear of its rapid destruction. It will likely not be completely immune to the effects of corrosion, but will last several decades before needing to be replaced.

Areas of application

The use of structural steels is quite widespread. As already noted, they are used for the production of machine parts and equipment that are subject to high operating loads, as well as for the assembly of load-bearing structures during the construction of various objects. In addition, the material is used for the manufacture of thrust bearings, spring mechanisms, heat-resistant boilers and furnaces.

High-quality structural steels are used in the production of boiler equipment, which is constantly exposed to high mechanical and thermal loads. This is a very good material that is in demand both among industrialists and individuals.

Some craftsmen make various tools from it, which have a much greater margin of safety than standard products. You can make high-quality gates or doors from metal that will reliably protect your home from uninvited visitors.

It’s not difficult to get material these days. You can order high-quality structural steel at almost any metallurgical plant. But before filling out an application, you should carefully familiarize yourself with the range of products and decipher all the designations encoded in the labeling in order to make the most correct choice.

The characteristics of structural steels are quite varied and the main thing is that they significantly affect the quality of the material. Therefore, careful preparation will help you avoid mistakes. You can receive your order by visiting the factory yourself. If this is not possible, you can order targeted delivery to anywhere in the country. Structural metals and alloys are more expensive than standard materials, but their high performance parameters deserve such treatment.

Source: https://promplace.ru/vidy-metallov-i-klassifikaciya-staty/konstrukcioonye-stali-1527.htm

Structural steel | GOSTs and TUs of the METALLSERVICE company

Divided into:

• Carbon quality steel
• Alloy quality steel, including:

• low alloy;
• alloyed;
• spring-spring;
• heat resistant;
• ball bearing

Steel range:

Carbon quality structural steel

Manufactured in accordance with GOST 1050 PDF.

In the steel grade designation, the numbers indicate the average carbon content in hundredths of a percent.

Carbon quality structural steel is divided into:

• mechanical engineering - 08, 10.20, 25, 30, 35, 40, 45, 50, 55, 58.60;
• automatic -A12, A20, A30;
• boiler room - 20K.

Purpose:

engineering steels - for the manufacture of machine parts and instrument structures;

automatic - for non-critical parts of mass production (small fasteners, etc.) manufactured on automatic machines;

boiler rooms - for the manufacture of boilers and vessels operating under pressure and at temperatures up to 450°C.

Substitutes for some steel grades:

St20 - St15, 25;

St35 - St30, 40, 35G;

St45- 40X, St50, 50G2.

Weldability: St08-St35 - good weldability, St45 - difficult to weld, boiler steels are welded well, automatic steels are not used for welding.

Alloy steel

Low alloy steel

Manufactured in accordance with GOST 19281-89 PDF.

Steel grades: 09G2, 09G2S, 0HSND, 17G1S, 16G2AF, etc.

Steel grades 10KhNDP, 15KhNDP, 0KhSND, 15KhSND are atmospheric corrosion-resistant (AKS), the thickness of metal structures made of AKS over 20-30 years of operation decreases by 2-3 times less than the thickness of structures made of conventional carbon and low-alloy steel.

Purpose: for the manufacture of railway, metro, tram car bodies, load-bearing structures of locomotives, agricultural and other field machines and engineering structures operating under conditions of variable dynamic loads and seasonal and daily heat changes.

Substitutes for some steel grades: 09G2S - 09G2, 09G2DT, 09G2T, 10G2S;

10HSND - 16GAF.

Weldability: weldable without restrictions.

Alloy structural steel

Manufactured according to GOST 4543-71 PDF

In the brand designation, the first two digits indicate the average carbon content in hundredths of a percent. The numbers after the letters indicate the approximate content of the alloying element in whole units. The absence of a number means that the content of this element is up to 1.5% (upper limit).

Depending on the chemical composition and properties, steel is divided into categories:

• quality (without letters);
• high quality A;
• especially high quality sh.

Purpose: various upgradeable parts; bushings, gears, cages, sleeves, disks, plungers, and other parts that require high surface hardness.

Substitutes for some grades of steel:

20Х - 15Х, 20ХН, 12ХН2, 18ХГТ;

30KhGSA - 40KhFA, 35KhM, 40KhN, 25KhGSA, 35KhGSA;

40Х - 45Х, 38ХА, 40ХН, 40ХС.

Weldability: welding alloy steels is somewhat difficult due to the tendency for the heat-affected zone to harden and the formation of brittle structures in it (special welding technology is required).

Heat resistant steel

Manufactured in accordance with GOST 20072-74 PDF.

Steel grades: 12МХ, 12Х1МФ, 25Х1МФ, 25Х2М1Ф, 20Х3МВФ, 15Х5М, 15ХМ.

Purpose: intended for parts operating under load at temperatures up to 6000C for a long time.

Weldability: limited or difficult to weld.

Ball bearing steel

Manufactured in accordance with GOST 801-79 PDF.

Brands: ShKh15, ShKh4, ShKh15SG, ShKh20SG.

In the designation of steel grades, letters and numbers mean: Ш - bearing; X - alloyed with chromium; number - chromium content, SG - alloyed with silicon and manganese.

Purpose: for the manufacture of parts operating under the influence of concentrated and alternating stresses arising in the contact zone of balls and rollers with the running tracks of rolling bearing rings.

Substitutes for some grades of steel:

ShKh15 - ShKh9, ShKh12, ShKh15SG;

ШХ15СГ - ХВГ, ШХ15, ХС, ХВСГ.

Weldability: welded using the KTS method

Spring steel

Source: https://Mc.ru/gost/construct_stal

Structural high-quality carbon steel

It is not without reason that high-quality carbon steels are called universal. Their use is widespread not only in the engineering industry and related fields, but also in construction. Individual elements and integral structures are made from high-quality carbon steels.

High-quality structural carbon steel and alloys based on it have become widespread due to their characteristics, which ensure a long service life and efficient use of products made from it.

During smelting, high-quality steels are subject to strict requirements for the selection of raw materials, casting method, and smelting technology.

Structural high-quality carbon steel

Classification of quality carbon steels

High-quality carbon steels and structural steels can be classified according to the following criteria:

• By purpose:
  1. for use in mechanical engineering;
  2. for use in construction;
• According to the amount of impurities that reduce quality:
  1. ordinary quality;
  2. quality;
  3. High Quality;
  4. especially high quality;

• By composition:
  1. presence of carbon:
     • low carbon;
     • medium carbon;
     • high carbon;
  2. presence of alloying elements:
     • low alloy;
     • medium alloyed;

• By delivery method:
  1. forged;
  2. rolled;
  3. calibrated;

• By processing:
  1. ordinary;
  2. boiler rooms;
  3. automatic;

• According to the degree of deoxidation:
  1. boiling (kp);
  2. semi-calm (ps);
  3. calm (no designation).

Visual classification of steel types

Deoxidation affects the homogeneity of the internal structures of the metal. The best in terms of homogeneity is calm (a, d), followed by semi-calm (c, f) and lower quality boiling (b, e). The internal structure is clearly shown in the figure.

General characteristics of high-quality carbon steels

The main differences between high-quality steels and ordinary quality steels are:

• a small amount of quality-reducing impurities: sulfur and phosphorus;
• narrow range of carbon amounts;
• increased amount of manganese or silicon.

The steel is supplied from the manufacturer with a guarantee of the declared composition of chemical elements and their inherent mechanical properties.

Speaking about the characteristics of high-quality steels, the most significant ones should be highlighted:

• high strength;
• plastic;
• impact viscosity.

Changes in the structure of steel ingots during hardening

But to improve performance characteristics, employees of institutes and laboratories are experimenting with the chemical composition, methods of increasing the strength and hardness of surfaces, heat treatment methods, and methods of melting and casting metal. The mechanical properties of high-quality carbon alloys depend on the chemical composition.

Properties inherent in carbon alloys:

• Low carbon – low strength with high ductility. They are used in the production and manufacture of parts and assemblies with complex structures and light loads. Properties inherent in carbon alloys:
• 15-20 – for non-critical parts that do not require additional heat treatment or have been subjected to normalization.
• Medium carbon - for the manufacture of parts that require high hardness, but with reduced ductility. Products that require heat treatment: hardening of the surface layer, improvement, normalization. To facilitate cutting, medium carbon steels are annealed.
• High-carbon, as well as with additionally introduced manganese, have high elasticity and wear resistance. Therefore, spring products are made from it.
• Automatic – used for processing on automated machines. Phosphorus and sulfur in greater quantities contribute to the formation of small chips, which has a positive effect on the machinability and durability of the tool, but the roughness of the machined surfaces suffers.

Download GOST 1050-88

Use of high-quality structural carbon steel

The scope of application is quite wide. The main consumers of alloys are the engineering and construction industries. One of the advantages is considered to be good weldability.

As the name suggests, “structural” means used for building metal structures. Another name is reinforcing steel.

Considering the main grades of quality steel used by industrial enterprises, they can be divided by purpose.

1. High-quality low-carbon steels 05-10. Their main purpose is the production of responsible and high-quality structures using welding (increasing the amount of carbon helps to reduce weldability). A small amount of carbon after welding does not provoke the formation of cracks in both hot and cold conditions.

1. High-quality low-carbon steels 12-20. Their main purpose is the production of structural elements and parts that are not critical, lightly loaded, and subsequently cemented. Processed by cutting, cold stamping, complex drawing. Surface requirements: wear resistance, high hardness with a soft core. We manufacture mechanical engineering elements (shaft, axle, bolt, coupling, fork, lever, flanges and others), as well as elements of boiler equipment operating at high pressure and temperatures from -40°C to 450°C (pipeline, tee, connecting flange and others).

1. High-quality medium carbon steels 25-35. Parts made from this material operate under medium loads and low stresses. After chemical-thermal exposure, they have high strength of the surface layer, wear resistance, but with insignificant strength of the core of the part (nut, screw, pawl, hook, cam, sprocket, etc.).
2. High-quality medium carbon steels 40-45. After heat treatment, products made from this material can withstand medium loads (shaft, gear, connecting rod, etc.) well. To obtain blanks, the method of hot die stamping is used. Subject to all methods of heat treatment. In all medium-carbon steels, after quenching and subsequent high tempering, the internal structure becomes tempered sorbitol. In connection with this, viscosity increases with plasticity, and this means low sensitivity of stress concentrators. As the diameter of the product increases, its hardenability decreases.

1. High-quality medium carbon steels 50-55. Parts made from these steels are highly loaded elements of mechanisms and assemblies (clutch, gear, spring ring, etc.).
2. High-quality high-carbon steels 60-80 (G). Parts are manufactured that are subjected to constant compression stresses, which are operated under friction conditions (eccentric, spring, spring, etc.), as well as those operating under heavy dynamic and static loads (torsion bar, cross).

1. High-quality boiler steel 12K-22K. They are used in the manufacture of parts whose operation involves elevated temperatures and high pressure. To improve weldability, titanium is introduced into the composition, and deoxidation is carried out by aluminum. Vessels and boilers that work with turbines, combustion chambers on ships and steam units are made from it.

1. Automatic steel. Widely used in the industrial production of fasteners for automobiles and assemblies operating under static loads (bolt, nut, stud).

An alphanumeric index is used for designation. The numbers indicate the percentage of carbon content (0.00%). The letters (kp, ps or sp) indicate the degree of deoxidation, the increased amount of manganese (G), aluminum (U), vanadium (F) and the processing method.

The letter A in front of the numbers indicates an automatic alloy, the letter K after the numbers means a boiler alloy, PV is made by hot rolling, OSV is a metal for the production of railway car axles.

To designate high-quality steels, in contrast to ordinary quality, “Steel” is written before the marking.

Examples:

1. Steel 10. carbon content is about 0.1%, the degree of deoxidation is calm.
2. Steel 10 kp. carbon is about 0.1%, boiling according to the degree of deoxidation.
3. Steel 20G. carbon about 0.2%, manganese up to 1%.
4. Steel 30G2. carbon about 0.3%, manganese up to 2%.
5. Steel A20. Automatic with an average carbon content of about 0.2%.
6. Steel 20K. Boiler room with an average carbon content of about 0.2%.

Structural high-quality carbon steel, grades, GOST standards. standards
Russia, GOST 1050-88	USA, AISI	EU, DIN
Steel 08 kp	A622	Fe P04/St 14
Steel 10	A1010	1.0301
Steel 15	A1015	1.0401
Steel 25	A1025	1.1158
Steel 20K	A285-A	Р265GH

Foreign manufacturers of similar products produce labeling according to their own standards.

Source: https://stankiexpert.ru/spravochnik/materialovedenie/stal-konstrukcionnaya-kachestvennaya-uglerodistaya.html

What is structural steel?

Divided into:

• Carbon quality steel
• Alloy quality steel, including:

• low alloy;
• alloyed;
• spring-spring;
• heat resistant;
• ball bearing

Steel range:

Let us tell you what structural steel is

The use of steel has long been widely accepted in our lives and no one doubts its feasibility. However, we should not forget that there are different steels. Today there are several types of this material:

1. Structural steel.
2. Tool steel.
3. Steel for individual purposes with special properties.

Let's talk today about structural steels. This is the name for all types that are used in the production of building structures, as well as machine parts and mechanisms.

Types of material

Structural steel is divided into two large groups:

1. High-quality structural alloy.
2. High-quality structural carbon.

All these types are used in one or another area of ​​production, performing the functions assigned to them.

Structural alloy steels

Quite often, to improve the technological, physico-chemical, and strength properties, various elements are added to steel, that is, it is alloyed. Basically, chromium, nickel, and manganese are used for these purposes. Structural high-quality steels can contain one or several such elements. In this regard, the following stand out:

• Low alloyed (the number of additives is no more than 2.5%).
• Medium alloyed (indicator can increase up to 10%).
• Highly alloyed (additional elements make up more than 10%).

In order to understand how additives work, you need to understand the composition of the material. It is based on ferrite (approximately 90% of the volume). Alloying elements dissolve in ferrite, thereby increasing its strength. Silicon, nickel and manganese are especially effective in this regard. But chromium, tungsten and molybdenum have a weaker effect.

It should be noted that alloyed structural steel has low weldability. This is due to the hardening of the heat-affected zone and the formation of structures within it that are brittle. Therefore, during the welding process, special technologies are used, developed individually for this type of steel.

Low-alloy structural steel is widely used for the production of locomotives, carriages, and agricultural machines. All these products are distinguished by their ability to withstand variable loads. The weldability parameters of such steel have no restrictions.

Turbine blades and rotors, reactors, steam pipes and collectors are made from high-alloy steel.

Structural carbon steel

The second variety is also represented by several types, such as:

• Mechanical engineering. This type of structural steel is used in the production of automobiles.
• Automatic. It is from this steel that various fasteners are made. It is in no way suitable for welding; all parts are machined.
• Boiler room. Indispensable when it comes to the manufacture of boilers and vessels that must withstand high temperatures. This steel has good weldability.

Structural steel is the material without which the manufacture of certain types of structures and parts becomes impossible.

Source: https://FB.ru/article/131521/rasskajem-chto-takoe-stal-konstruktsionnaya

Construction steels

Structural steel is a type of iron-carbon alloy intended for the manufacture of building structures, fittings and castings. It has an optimal composition to withstand significant design loads. Using, for example, tool steel for the manufacture of a construction beam is impractical - even with similar dimensions, its technical characteristics will not satisfy design standards.

Classification

Requirements for construction steels are regulated by GOST 27772-88* “Rolled steel for building steel structures”. The document defines the range of alloys, provides classification, rules for production, acceptance and use of the metal.

According to GOST, steels are divided into 2 main types according to composition:

• Carbonaceous.
• Alloyed.

Carbon

The amount of the chemical element carbon determines the strength of a steel structure. The more it is, the stronger the metal. Carbon alloys are divided into 3 groups:

• Construction low-alloy steels with a carbon content of less than 0.25%;
• Medium carbon contains 0.25-0.60% carbon;
• High-carbon ones contain more than 0.60% of the chemical element.

Metals with different amounts of carbon are used in the manufacture of building structures of normal tension.

Alloyed

To increase strength, various metals are added to the iron alloy in different quantities. This process is called doping. Based on the number of additives, there are 3 groups of alloys:

• Low alloy – up to 2.5% additional metals;
• Medium alloyed - about 2.5-10% additives;
• Highly alloyed - more than 10% impurities.

Construction steels with additives (alloyed) are considered to be of higher quality than carbon steels. They are used for the manufacture of critical structures in construction, the space industry, mechanical engineering and the railways.

The choice of steel type is determined by GOST and structural calculations.

Marking of construction steels

The brand indicates the main characteristics of the material. Carbon and alloy steels have different designations, so we will consider them separately.

Decoding carbon steels

It’s easy to decipher the grade of carbon alloy:

• “St” is the designation of construction steel;
• The number indicates the amount of carbon in the alloy in tenths of a percent;
• The letters “kp”, “ps”, “sp” at the end of the designation indicate the boiling type of deoxidation (see below). The absence of additional letters indicates that the steel is calm.

The ratio of steel grade and amount of carbon is presented in the table:

sulfur in carbon alloys - not less than 0.045%, phosphorus - not less than 0.055%.

Marking of alloy alloys

Since alloy steels contain various chemical elements, it is necessary to identify them:

An example of a grade of construction steel with alloying additives: 16G2AF. The designation is deciphered as follows:

• 16 – carbon content in the alloy. In our case – 0.16%. If the name has one digit, it should be taken as a hundredth of a percent;
• G – presence of manganese 2%;
• A – nitrogen, about 1%;
• F – vanadium, about 1%.

There are many names of alloyed construction steels.

Designation of structural steel

GOST 27772-88* provides the designation of metals for the manufacture of shaped rolled products, which are designated by the letter “C” (Construction steel) and numbers. To understand what is hidden behind these values, we present the correspondence of alloyed, carbon and accepted construction steels:

Main classification of construction steels

Alloy and carbon are the main classification of alloys. Additionally, metal can be divided into groups according to individual key characteristics.

By strength:

• 1) Conventional (sy < 29 kN/cm2) are low-carbon in the range (C235C285) with varying degrees of deoxidation. Characterized by average resistance to corrosion, brittleness at low temperatures;
• 2) Increased strength (29 kN/cm2≤sy

Source: http://www.hugebuilding.ru/osnovnye-svojstva-i-marki-stroitelnyh-stalej.html

Structural steels

Steel includes a huge group of materials that are alloys of iron, carbon and other substances. carbon is the main parameter of steel, affecting all properties. Steel includes alloys with a carbon content from 0.05 to 2.14%. The minimum iron content is 45%.

carbon is the main parameter of steel, affecting all properties

According to purpose, steel is divided into three groups:

1. Structural;
2. Instrumental;
3. Special.

In terms of production volume, the main part falls on structural steel. It contains up to 1.2-1.3% carbon. Based on quality, all grades of structural steel can be divided into several groups.

Regular quality structural carbon steel

This group includes steels with the highest content of unregulated impurities - gases, non-metallic inclusions, and other metals. The following elements may be present in the steel composition in small quantities, specified in the standards:

1. Phosphorus and sulfur are the most harmful impurities. They worsen the mechanical properties of steel.
2. Silicon and manganese. In small quantities they have little effect on the properties of steels and slightly improve weldability.
3. Other metals - chromium, copper, nickel, etc. The permissible amount without affecting the properties of the material is 0.3%.

Steel of ordinary quality is marked with the letters St or VSt, followed by a single-digit number indicating the alloy number, and the method of deoxidation - removing oxygen from the alloy. Examples: St0, St5kp. carbon in these steels is 0.06-0.65%.

Increasing the amount of carbon leads to increased hardness, but also increases brittleness. Steels with a small amount of carbon are characterized by high ductility, which allows them to be used for the production of wire by drawing. The remaining steels are processed at the initial stage by rolling.

Steel products with a carbon content of more than 0.35% can be hardened.

Standard quality steels are characterized by satisfactory mechanical properties combined with ease of processing and low cost. Therefore, they are widely used to create non-critical structures with light loads. The main part of metal structures is made from steels of this group.

Quality structural carbon steel

Steel of this group differs from steel of ordinary quality in that it has more stringent requirements for the chemical composition, especially for harmful impurities. The amount of carbon is 0.05-0.6%.

The production of products from this steel is carried out by rolling, followed by forging or stamping. Also, parts made of high-quality steel are subjected to thermal and chemical-thermal treatment to improve mechanical properties.

This group of steels is used for the manufacture of structures and machine parts that are subject to moderate loads.

To designate alloys from this group, a two-digit number is used, indicating the carbon content in hundredths of a percent, which may be followed by letters indicating the characteristics of the steel. Alloy examples: 08, 15kp.

Alloy structural carbon steel

This group of steels is the most numerous in terms of the number of alloys used. In terms of the content of harmful impurities, these alloys have the same restrictions as high-quality steel. The amount of carbon is also similar. The difference is that alloy steels contain additives of other elements, mainly metals, which increase various performance properties.

Alloy structural steel is divided into 3 subgroups:

• Low alloy - less than 2.5% alloying elements;
• Medium alloyed - 2.5-6% alloying elements;
• Highly alloyed - more than 6% alloying elements.

The use of alloying substances significantly increases the cost of steel, so alloyed alloys are used where they are needed. The most widespread are low-alloy alloys containing chromium, silicon, manganese and nickel.

Such alloys have good strength, reduced sensitivity to aging, good weldability, ease of cutting and pressure processing. They are used for critical structures subject to high loads.

Processing methods are similar to those used for quality structural steel.

The designation of alloy steels consists of a two-digit number indicating the carbon content in hundredths of a percent, and large letters indicating alloying substances. The number after the letter indicates the content as a percentage; if 1 or less, then it is not written. Examples: 20ХМ, 35Г, 40Х2Г2М.

A special group of alloy steels are stainless alloys. They belong to high-alloy steel - the content of chromium alone exceeds 12%. In addition to chromium, stainless steels contain chromium, nickel, manganese, and titanium. Examples: 03Х19Г10Н7М2, 12Х18Н10Т.

Special structural steel

Steels of this group are used for the following structures:

• Ship hulls;
• Bearings;
• Railway rails;
• Bandages;
• Axles and wheels, etc.

These steels are designated differently. For example, bearing steels are designated by the letters ШХ, followed by numbers indicating the alloy number and other letters. All special structural steels are characterized by high strength, but may contain varying amounts of carbon.

The article is for informational purposes only.
Don't forget to consult with experts.

Source: https://samara-metall.ru/articles/konstrukcionnaye-stali

What are structural alloy steels and where are they used?

Alloy structural steel is indispensable for production in construction and mechanical engineering. This is due to the fact that it has certain mechanical, physical and chemical properties. A certain property is specified by the content of a particular element, due to the content of which it will be endowed with a certain quality.

Steel composition

Alloy steel uses the following elements in its composition:

Manganese (Mn) - G; silicon (Si) - C; chromium (Cr) - X; nickel (Ni) - H; copper (Cu) - D; nitrogen (N) - A; vanadium (V) - F; niobium (Nb) - B; tungsten (W) - B; selenium (Se) - E; cobalt (Co) - K; beryllium (Be) - L; molybdenum (Mo) - M; boron (B) - P; titanium (Ti) - T; aluminum (Al) - Yu.

In addition to the basic elements included, the following have been added:

• Chroma.
• Nickel.
• Cobalt.
• Aluminum.
• Vanadia

The main one of the most important parameters by which steel is divided into various classes is their chemical composition of elements.

The remaining additions give the metal its distinctive qualities. The added chromium gives the alloy an increased level of strength and fluidity, despite this, maintaining an acceptable level of toughness. The addition of tungsten provides the alloy with normal hardness and sets a good level of stability during tempering. The addition of molybdenum sets the level of hardenability and increases the level of ductility and viscosity.

Composition differences vary based on the total percentage of alloying elements:

• For highly alloyed ones – more than 10%.
• For medium alloyed ones – more than 2.5 – 10%.
• For low-alloyed ones – no more than 2.5%.

Structural alloy steels have a certain advantage after heat treatment, in contrast to carbon steels. This suggests that alloying elements significantly influence the diffusion processes that occur during heat treatment. A larger number of alloying elements have been added to the material, which is why they come in the guise of rolled products, these are round, square, hexagonal, and sometimes as calibration sheets, forgings and other semi-finished products.

Read also: Polishing stainless steel: techniques and tools

How is structural alloy steel marked?

Grades of structural alloy steels consist of letters and numbers. Letters are alloying elements, each of which is included in the composition. The number indicates the quantitative presence of carbon and alloying element.

They are marked this way. A two-digit number is placed at the beginning, which expresses the approximate average level of carbon contained, which is indicated in hundredths of a percent. Letters indicate alloying elements. The current markings are: X-Cr, N - Ni, M-Mo, G - Mn, D - Cu, B-W, F-V, B - Nb, P - B, K-Co, C-Si, T - Ti, C - Zr, Yu - A1, P - P, A-N. The numbers after the letter indicate the average occurrence of the specified element as a percentage.

In the case where the contained element has a content of less than 1%, the number is not given. If there is an “A” at the end, it means the steel is of high quality. This means that the amount of sulfur and phosphorus contained is no more than 0.02%.

Where is structural alloy steel used?

Since the scope of application of structural steel is very wide, it is important to know the area of ​​​​use of the material, and what grade is used for what.

• 60С2(A) – for springs, for the production of which strip steel with a thickness of 3 to 16 mm is used. Spring bands, thickness from 0.08 to 3 mm. Twisted springs made of 16 mm wire.
• 70SZA – for heavily loaded springs with critical purposes. Steel prone to graphitization.
• 50ХГ(А) – for springs, the production of which requires strip steel from 3 to 18 mm in thickness.
• 50HFA (HGFA) - for critical springs and springs that operate at elevated temperatures, which do not exceed 300 degrees, or for those subjected to frequent variable loads.
• 60C2XA – for large, highly loaded springs and springs with critical applications.
• 60C2H2A(C2BA) – for critical, highly loaded springs and springs, which are made of spring bands and calibrated steels.
• 20X – for claw couplings, bushings, spindles, guide bars, plungers, mandrels, copiers, spline rollers, etc.
• 40X – for gears, spindles and shafts in rolling bearings, worm shafts.
• 45X, 50X - for gears, spindles, shafts in rolling bearings, worm and spline shafts, as well as other parts that operate at medium speed and medium pressure.
• 38ХА - for gears that operate at medium speed and medium pressure.
• 45G2, 50G2 - for large lightly loaded parts, including shafts, gears on heavy machines, etc.
• 18ХГТ - for parts that operate at high speed under high pressure and load.
• 20ХГР – for heavily loaded parts that operate at high speed and load.
• 15ХФ - for small parts that are subjected to carburization and hardening with low tempering.
• 40ХС – for small parts that have a high level of strength.
• 40HFA - for critical and high-strength parts that are subject to hardening and high tempering. For small and medium-sized parts with complex shapes that are subject to wear. Also critical welded structures that operate under alternating load conditions.
• 35ХМ – for shafts, turbine parts and fasteners that operate at elevated temperatures.

Since each type of steel has its own specific advantages, it is important to understand which will be most suitable for what. As the main parts that experience severe loads and have a high level of wear, alloyed structural steels of their grade and application are indispensable.

You may also like

Medicine is a field in which sterility and quality

Source: http://solidiron.ru/steel/chto-takoe-konstrukcionnye-legirovannye-stali.html

Forging from structural steel 170×950 mm art. 45 GOST 8479 – KMI Company, LLP

Product from the manufacturer

In stock

Wholesale:

• Spot,
• Cashless,
• Visa/Mastercard
• Details

• Pickup,
• Courier,
• Transport company
• Details

Specifications

• Country of manufactureRussia

Description

A forging made of structural steel is a semi-finished product. Produced by stamping or forging. As a rule, the forging can be either round or rectangular. Most often, its shape and size depend on the final product.

Structural steel forging. Characteristics

• Brand: Art. 45
• Size: 170x950 mm
• Standard: GOST 8479

Structural steel forging. Purpose

These forgings are used to make:

• Cylinders.
• Shafts.
• Pipe blanks.
• Plates for stamping.
• Rolls of various rolling types.
• Balls.
• Gears.
• Fastening elements.

Industries of use.

• Mechanical engineering.
• Shipbuilding.
• Atomic industry.
• Mining industry.
• Chemical industry.
• Energy.
• Agriculture.
• Automotive industry.

You can buy forgings made of structural steel at a competitive price from stock and to order directly from KMI Company LLP

The price is determined by the volume of products, payment terms, place and method of delivery. The minimum order amount is 28,000 tenge. Please check with the sales department for the final cost.

Advantages of working with KMI Company LLP

• KAZAKHSTAN METAL INDUSTRIAL COMPANY is part of a large international holding company operating in Russia, Kazakhstan, China, Uzbekistan and Kyrgyzstan for more than 10 years.
• Thanks to our network of warehouses in different countries, we offer the most favorable conditions for purchasing rolled metal products.
• We have created an extensive system of working with the largest manufacturers of metal products and have streamlined logistics so that you save time and money.

This price list is for informational purposes only and under no circumstances is it a public offer as defined by the provisions of Art. 447 of the Civil Code of the Republic of Kazakhstan.

Contact the seller

Source: https://tj.all.biz/pokovka-iz-konstrukcionnoj-stali-170x950-mm-st-45-g3116966KZ