How to decipher steel grades

What types and grades of carbon steel exist?

The technical characteristics of steels directly depend on the quantity and quality of their constituent elements (carbon). The more it is, the harder the alloy and the higher its fragility. Carbon steels of various grades are characterized by a low content of alloying components. Typically, each of them does not exceed 1.5% and has a minor effect on the technical characteristics of the alloy.

Carbon steels are produced in the form of rolled products and shaped castings. They are widely used in all sectors of industry, construction, and everyday life. Metallurgical enterprises transfer slabs and blooms for further processing into sheets, rolled profiles, and pipes of various diameters.

What are carbon steels?

Carbon steels are an iron alloy with a carbon content of up to 0.6%. The amount of sulfur and phosphorus depends on the quality of the metal. Alloying elements are present in small quantities. Qualitative characteristics depend on the amount of carbon, sulfur, phosphorus, manganese and silicon.

• hardness;
• weldability;
• strength;
• viscosity;
• elasticity.

The more carbon, the higher the hardness, brittleness and worse weldability.

General characteristics

Carbon steel is divided into 3 groups according to the requirements for chemical composition and mechanical properties. Letter designation. The defining factors for the group are:

• A - mechanical properties;
• B - chemical composition;
• B - the chemical composition and basic mechanical properties are strictly maintained.

Group B alloys are chemically tested, and a sample is taken from the ladle during a spill to check mechanical properties - tensile and flexural strength, impact strength. Hardness is controlled by heat treatment.

Composition of chemical elements

The main element is iron. The relationship to the group is determined by the amount of carbon. non-metallic inclusions of phosphorus and sulfur impair mechanical properties. They contribute to red brittleness and cold brittleness, the formation of cracks in hot and cold metal.

Corrosion resistance is ensured by low carbon content and the addition of chromium. The amount of chemical elements in carbon steel, manganese and silicon, depends on the deoxidation method and quality class. Manganese can be present within 1.2% in normal quality alloys, up to 1.8% in high quality alloys. silicon does not exceed 0.3%.

High-quality steels of group B are checked for their properties and chemical composition. The permissible amount of non-metallic inclusions is 0.03–0.0018%.

The amount of carbon determines the hardness of steel, its ability to harden and weld.

The lower the carbon index, the better the metal is welded. St 40X requires heating before welding, St 6 requires heating to 700⁰ and post-welding tempering. Hardenability is the opposite. Up to St4 alloys do not heat up and do not change their hardness. 40x steel can crack when exposed to sudden cooling in water.

Classification by degree of deoxidation

According to the degree of deoxidation, carbon alloys are divided into the following types:

• boiling;
• calm;
• semi-calm.

Boiling alloys of ordinary quality are released from the furnace immediately after adding the deoxidizer. In some cases, deoxidation is carried out in a ladle. As a result, many air bubbles form under the crust.

For tool alloys, the deoxidation reaction begins before the spill and ends completely when poured into the ladle.

Boiling steels are used for the production of ingots, slabs and blooms - large-section rolled products.
Subsequently, they are melted down into high-quality metal in electric furnaces or converted into rolled products of a smaller diameter - round, square. During processing, air escapes and the grain is pulled lengthwise, increasing the mechanical properties of the steel. Semi-quiet steels are characterized by increased malleability. Classification of carbon steels | Matved 4

Production methods and quality differences

According to production methods, alloys are divided into three types:

• open hearth;
• convector;
• in electric furnaces.

The production method and quality division are indicated in the metal certificate and can be indicated letter-wise at the end of the marking. For example, VD is electric arc remelting, Sh is slag remelting.

Open hearth furnaces with the lowest quality are used for reworking and rolling of group A. Electric furnaces produce an alloy of high and very high quality.

Application area

Carbon steel is used to make welded building structures, water and gas pipes, parts of machine tools and automobiles, rolled round and other sections for the manufacture of various objects, fences, and gratings.

Marking features

The marking of carbon steels has an alphanumeric meaning and is indicated at the end of the rolled product by a certain color. St at the beginning means normal quality. Then comes a number indicating the amount of carbon and the method of deoxidation.

For a material with increased quality, the designation begins with the word Steel, then carbon in hundredths and the letter designation of alloying elements.

High-quality ones are designated at the end with the letter A. Special, high-carbon, instrumental - U, high-speed - R.

Marked carbon steel

How to decipher steel markings

The grade of carbon steel and its quality group can be determined by the type of marking. Each number and letter has its own meaning and shows quality requirements, the degree of deoxidation, and the presence of alloying elements.

For example, for a regular quality alloy:

• St 2 kp - normal quality with carbon content 0.09–0.15%, boiling, manganese 0.25–0.50%, silicon less than 0.05%;
• St3G PS - carbon content in the range of 0.14–0.22%, semi-quiet, manganese in the range of 0.80–1.1%, silicon not more than 0.15%.

High quality carbon steels are marked with numbers (carbon content in hundredths) and letters (alloying element). For example:

• 45 - 0.45% carbon;
• 40ХН - carbon 0.4%, chromium and nickel less than 2%.

The decoding of high-carbon grades has a letter indicating the type of material, its application and a number - the percentage of carbon in tenths. Tool alloys are designated U. For example:

• U8 - instrumental, 0.8% carbon;
• U12 - carbon content 1.2%.

The chemical composition can be more accurately determined from the table in the metallurgist's reference book.

The rolled product is marked with a colored stripe at the end:

• red - St3;
• yellow - St2;
• green - ST5;
• blue - St6.

Each type of steel has its own marking.
Doped ones can contain up to 3 color stripes. Marking of steel for a knife, decoding of the grade of steel for a knife, properties of alloy steel for a knife

Which companies produce carbon steel?

The largest producer of carbon steel is the Mechel full-cycle metallurgical plant. It unites several large plants, ranging from coke production to various rolled products. In addition, rolled steel is produced by metallurgical plants:

• "Chelyabinsk";
• "Ukrainian Forge" - Chelyabinsk region;
• "Izhstal" - Udmurtia;
• Beloretsk Iron and Steel Works - Bashkortostan.

The metallurgical industry for the production of ferrous metal is located closer to iron ore and coal deposits. For non-ferrous casting factories, energy sources are more important.

Source: https://metalloy.ru/stal/uglerodistaya-marki

Metal grades decoding table - Metalworker's Directory

Steel, cast iron and alloys of non-ferrous metals are subject to mandatory marking. There are more than 1.5 thousand different types of steels and alloys made from them in the world.

Alloyed steels , unlike unalloyed steels, have a slightly different designation, since they contain elements that are specially introduced in certain quantities to ensure the required physical or mechanical properties. Eg:

• chromium (Cr) increases hardness and strength
• Nickel (Ni) provides corrosion resistance and increases hardenability
• Cobalt (Co) improves heat resistance and increases impact resistance
• Niobium (Nb) helps improve acid resistance and reduces corrosion in welded structures.

That is why it is customary to include in the names of alloy steels the chemical elements present in the composition and their percentage content. Chemical elements in such steel grades are designated by Russian letters given in the table.

X-chrome	A-nitrogen
C-silicon	N-nickel
D-copper	M-molybdenum
T-titanium	K-cobalt
B-tungsten	B-niobium
G-manganese	E-selenium
F-vanadium	C-zirconium
R-boron	U-aluminum

There is also a marking H , which tells us that the alloy contains rare earth metals, such as cerium, lanthanum, neodymium and others. Cerium (Ce) affects the strength and ductility of steel, and neodymium (Nd) and lanthanum (La) reduce porosity and sulfur content in steel and refine the grain.

An example of decoding steel grade 12Х18Н10Т

12Х18Н10Т is a popular austenitic steel, which is used in welding machines operating in dilute acid solutions, in solutions of alkalis and salts, as well as in parts operating under high pressure and in a wide temperature range. So, what do these mysterious symbols in the name mean, and how to combine them correctly?

The two numbers at the very beginning of the alloy steel grade are the average carbon content in hundredths of a percent. In our case, the carbon content is 0.12%. Sometimes, instead of two numbers, there is only one: it shows how much carbon (C) is contained in tenths of a percent. If there are no numbers at the beginning of the steel grade, this means that there is a fairly decent amount of carbon in it - from 1% and above.

The letter X and the number 18 following it indicate that this brand contains 18% chromium. Please note: the ratio of an element in fractions of a percent expresses only the first number at the beginning of the mark, and this only applies to carbon! All other numbers present in the name express the number of specific elements as a percentage.

Combination H10 follows. As you may have guessed, this is 10% nickel.

At the very end there is the letter T without any numbers. This means that the content of the element is too small to pay attention to. As a rule, about 1% (sometimes up to 1.5%). It turns out that in this grade of alloy steel the amount of titanium does not exceed 1.5%.

If suddenly at the very end of the brand you find a modestly standing letter A, remember that it plays a very important role: this means high-quality steel, the content of phosphorus and sulfur in which is kept to a minimum.

Two letters A at the very end (AA) indicate that this grade of steel is especially pure, i.e. there is practically no sulfur and phosphorus here.

In the course of a simple analysis of combinations of letters and numbers, we found out that the steel grade 12Х18Н10Т (structural cryogenic, austenitic class) reports the following information about itself: 0.12% carbon, 18% chromium (X), 10% nickel (N) and a small content titanium (T), not exceeding 1.5%.

At the beginning of the alloy steel grade there may also be additional designations:

R - high-speed;

Ш - ball bearing;

A - automatic (do not confuse with the letter A at the end of the name, which indicates the purity of the steel!);

E - electrical.

It is also worth noting some features of these subtypes of alloy steels:

1. in ball bearing steels, the chromium content is indicated in tenths of a percent (for example, ShKh4 steel contains 0.4% chromium);
2. in grades of high-speed steel, after the letter P there is immediately a number indicating the tungsten content as a percentage. Also, all high-speed steels contain 4% chromium (X).

To show the method of steel deoxidation, there are special letter designations: 

• sp - mild steel;
• ps - semi-quiet steel;
• kp - boiling steel.

Now let's take a closer look at how to decipher the grade of unalloyed steel , which is divided into ordinary and high-quality.

Ordinary unalloyed steel (St3, St3kp) has the letters St at the very beginning. This is followed by numbers indicating the carbon content in steel in tenths of a percent.

At the end there may be special indices: for example, St3kp steel belongs to the boiling category, as indicated by the letters kp at the very end. The absence of an index means that this steel is calm.

letters sv are added at the end . For example: St3st.

High-quality unalloyed steel (St10, St30, St20, St45) contains a two-digit number in the marking, indicating the average carbon content in the steel in hundredths of a percent. Thus, steel grade St10 contains 0.1% carbon; St30 has 0.3% carbon; St20 - 0.2%; St45 contains 0.45% carbon.

Structural low-alloy steel 09G2S contains the following chemical elements: 0.09% carbon, 2% manganese and a small amount of silicon (approximately 1%).

Steels 10KhSND and 15KhSND differ only in different carbon content: 0.1% and 0.15%, respectively. There is very little chromium (X), silicon (C), nickel (H) and copper (D) here (up to 1-1.5%), so numbers are not placed after the letter.

High-quality steels are used for the production of steam boilers and high-pressure vessels. Their markings have the letter K at the end: 20K, 30K, 22K.

If the steel is structural casting , then the letter L is placed at the end of the marking. For example: 40ХЛ, 35ХЛ.

Non-alloy tool steels are designated by the letter U. This is followed by a number expressing the average carbon content in the steel: U10, U7, U8. If the steel is also high-quality, this is also noted in the marking: U8A, U10A, U12A. If it is necessary to emphasize the increased manganese content, an additional letter G is used. For example, there are U8GA and U10GA steels.

Tool alloy steels have the same designation as structural alloy steels. For example, the HVG brand indicates the presence of three main alloying elements: chromium (X), tungsten (B) and manganese (G). There is approximately 1% carbon here, and therefore the number is not written at the beginning of the stamp. Another type of steel, 9KhVG, has a lower carbon content compared to KhVG: here there is 0.9% carbon.

High-speed steels are marked with the letter P, followed by the tungsten content in %. steel R6M5F3 as an example . It is high-speed (P), contains 6% tungsten, 5% molybdenum (M) and 3% vanadium (F).

Unalloyed electrical steel (ARMCO) has a very low electrical resistivity. This is achieved due to the minimal amount of carbon in the composition (less than 0.04%). Such steel is also commonly called technically pure iron . The marking of electrical non-alloy steels consists only of numbers. For example: 10880, 21880, etc.

Each number contains important information. The very first digit shows the type of processing: 1 - forged or hot-rolled; 2 - calibrated. The second digit indicates the presence/absence of a normalized aging coefficient: 0 - without a coefficient; 1 - with a coefficient. The third digit is the group according to the main standardized characteristic.

The last two are associated with the values ​​of the main standardized characteristic.

Structural steel is marked with the letter C, followed by the minimum yield strength of the steel. Additional designations are also used: K - increased corrosion resistance (S390K, S375K); T - heat-strengthened rolled products (S345T, S390T); D - increased copper content (S345D, S375D).

Aluminum casting alloys are designated by the letters AL at the beginning of the marking. Here are some examples: AL4, AL19, AL27.

Aluminum alloys for forging and stamping contain the letters AK, and then the conditional number of this alloy: AK6, AK5.

There are also wrought alloys containing aluminum . Avial alloy: AB, aluminum-magnesium alloy: AMg; aluminum-manganese alloy: AMts.

Now you have learned how to decipher the grade of steel containing various chemical elements. This steel marking was developed back in the USSR and is still in effect not only in the Russian Federation, but also in the CIS countries.

European steel markings are subject to the EN 100 27 standard. Japan and the United States have their own standards. There is currently no single world classification of steels.

Understanding the general rules for designating grades of unalloyed and alloyed steels, as well as by correctly deciphering steel grades, you can easily determine what kind of steel a particular part is made of.

Competent employees of the UralTeploMontazh plant will help you determine the required grade of steel that can withstand the required pressure and specified temperature conditions.

We always have in stock (or on order) steel fittings for pipelines, bent elbows and other pipeline fittings made of various grades of steel.

Source: https://ssk2121.com/marki-metallov-rasshifrovka-tablitsa/

Carbon steel grade St1ps, steel grade characteristics St1ps

Steel grade: St1ps.

Class: structural carbon steel of ordinary quality.

Industrial uses: high toughness and low hardness parts, anchor bolts, sheathing connections, non-critical fittings, rivets and boiler connections.

Foreign analogues of steel grade 20
Germany	S185
France	S185
European Union	S185
Italy	S185
China	Q195
Bulgaria	ASt0, ASt1
Hungary	Fe310O
Poland	St0S
Czech	10000

On our company's website you can find information on various grades of steel. This section provides useful facts about common quality structural carbon steel. The grade of carbon steel under consideration, St1ps, is widely used in industry. Various types of rolled products are created from it.

Decoding St1ps

A professional can “read” the basic information on the steel grade St1ps, knowing how the signs that make up its name are deciphered. In this case, the combination of the letters “S” and “T” means “steel”.

The number “1” coming after is the conditional brand number. The number is determined by the chemical composition. The higher the number, the more carbon contained in the composition, and also the higher the tensile strength value.

After the unit in the name there are the letters “PS”, which mean a semi-calm degree of deoxidation of steel (calm and boiling also happen).

Steel grade St1ps and its characteristics

St1ps GOST 380 - 2005 (the range is divided into rolled products, GOST 535-2005 and wire rod, GOST 30136-95) is used for the manufacture of elements characterized by high viscosity and low hardness.

St1ps has a large number of foreign analogues. For example, in Germany, France and Italy and throughout the European Union, the composition of this steel is similar to grade S185. In the USA, A283A and A283B can be used instead, in China Q195, in Bulgaria ASt0 and ASt1, in Poland St0S, etc.

St1ps steel is used to create anchor bolts; fittings that cannot withstand heavy loads; binding shells; fastening elements allowing the production of permanent connections; boiler connections.

At a temperature of 20 degrees Celsius, the temporary tensile strength of this material is 320-420 MPa, and the proportionality limit (yield limit for permanent deformation) is 190-220 MPa.

This brand contains various chemical elements. Carbon contains about 0.06 - 0.12 percent, silicon in the amount of 0.05 - 0.15 percent, manganese in the composition - 0.25 - 0.5 percent. There is also up to 0.05 percent sulfur and up to 0.04 percent phosphorus. Approximately 99 percent is iron.

Is St1ps steel required?

If you are interested in purchasing products made using St1ps carbon steel, please contact our specialists.
The assortment includes various metal parts, long and shaped steel elements. You can also order individual products according to your own drawings and sizes. Our website also contains information on other popular types of steel.

Source: http://atl-met.ru/stal-st1ps

Decoding steels

The most common group of metals used is steel. It should be noted that all steels, cast irons and alloys are required to be marked. In nature there are a huge number of different types of alloys and steels.

Understanding the markings is not that difficult; you just need to have some knowledge and information about metal products. Before considering the different types of steel, you must first understand what designations these additives have, since their markings include the following letter values:

N – nickel;

U – aluminum;

X – chromium;

C – silicon;

B – tungsten;

F – vanadium and many other elements.

All symbols of the Russian alphabet are available in the table on the website on the Internet. At first glance, understanding the markings may seem like a difficult task, but it is not. The designations of steel can be easily understood, you just need to familiarize yourself with the chemical composition and physical characteristics of the metal and understand the principle of composition.

Marking also depends on the classification of steel, which is carried out according to their intended purpose.

There are tool and structural types of steel. They are not the same in their physical and chemical properties.

For example, structural steel grades are widely used to produce products needed in the engineering and construction industries. And in the manufacture of stamped and measuring instruments, you will need tool steel.

This category of steel is also used for the production of impact tools, and the marking indicates the characteristics and quality of the product.

The industrial designation of steels and their alloys makes it possible to carry out work at a high quality level. For example, marking pipe metal helps builders to correctly carry out work with water supply communications. In turn, this prevents unexpected accidents.

Any rolled metal product has its own marking. In turn, unalloyed steels are divided into high-quality and ordinary steels. Moreover, the fewer harmful elements in the metal, the higher the quality. For a more detailed acquaintance, let’s take a closer look at the marking of steels.

They are also classified according to their intended purpose into structural and tool steels. The first type is subject to processing and is widely used in the creation of various structures and machine parts.

The marking of tool carbon steel is indicated by the letter “U”, followed by numbers confirming the carbon content as a percentage (U8, U10, U12). Strips, rods, squares, circles are made of tool steel.

An example is U10A steel - high-quality carbon steel with a carbon content of 1.0%.

The letter A indicates that this is high quality steel. It is also used for the production of various tools and has increased machinability. Its designation also depends on the purpose of the steel. This segment is used for auxiliary, impact and cutting tools.

U7, U7A steel is widely used in the manufacture of chisels, axes, sledgehammers, chisels, hammers and many other tools.

The steel marking “U7” shows that 0.7% carbon is present, and high-quality steels are marked: U8A, U10A, U12A.

If manganese is present in the steel, then the letter G should be used (U8GA and U10GA) and so on.

The designation ХВГ shows that steel contains three main alloying components: tungsten, chromium and manganese. It should be remembered that if the alloy contains no more than 1% carbon, then the number is not written in this case.

For example, steel grades such as U8, U8A, U8G are actively used for the manufacture of cutters, countersinks, screwdrivers, saws and other purposes.

Tool steel U13, contains 1.3% carbon. It is used to make punches, surgical instruments, razors and much more. Steels are mainly divided into structural and alloyed.

Ordinary quality steel does not contain alloying elements in its structure. They are marked with two letters “St”. After them comes a number that determines the carbon content as a percentage.

Alloy steels differ from unalloyed steels and are designated by different markings. They contain special components to achieve mechanical and physical properties.

For example: Co - cobalt increases not only impact resistance, but also heat resistance.

Ni – nickel can provide corrosion resistance.

Nb – niobium prevents corrosion processes and increases the acid resistance of steel.

Cr – chromium gives the metal hardness. In the marking of alloy steels, chemical elements are indicated by Russian letters.

You can go online and see all the designations you are interested in:

A – nitrogen,

C – silicon,

B – tungsten,

D – copper,

X – chromium and many other chemical elements.

You can also see that there are additional letters at the beginning of the alloy steel designation:

A – autonomous;

E – electrical;

Ш – ball bearing;

R – high-speed steel.

All designations appear at the beginning; if the letter “A” appears at the end, this confirms the purity of the steel.

Let's figure out how to decipher unalloyed steels. They are divided into ordinary and high-quality brands.

Unalloyed ordinary steel – St3, St3kp. Behind the letters are numbers showing the carbon content as a percentage. If the number is followed by the letter combination kp, then this category refers to boiling steel. In the absence of such a designation, we see that this is calm steel.

But, if it is necessary to show the weldability of the metal in the marking, then two letters St. are added. For example: St3sv.

For the manufacture of steam boilers, high-quality steel is used, with the letter “K” at the end: 20K, 22K and so on. It must be remembered that in order to correctly determine the designation of steel, you need to take into account its chemical components, purpose and deoxidation. We have already become familiar with the different grades and markings of steel.

According to their purpose, steels come in different categories: tool, structural, high-quality, high-quality and especially high-quality. There is also such a thing as deoxidation, which includes: boiling, calm and semi-quiet steels. Having certain knowledge, it will be easy for you to navigate the choice of steel products for construction work and other purposes.

For example, structural steel 09G2S is considered the most popular in industry and construction.

The decryption looks like this:

09 – carbon ratio in steel – 0.09%;

G2 – 2% manganese;

C – 1% silicon.

The interpretation of 09g2s steel is not at all limited to three alloying elements. In addition to the listed components, sulfur, chromium, nitrogen, nickel and many other chemical elements may also be present. It is very important to pay attention to the designation and marking of steel products, as they have different purposes.

For example, tool carbon steels with a carbon content of 0.8 -1.2% are used for the production of equipment and various tools. If the carbon content is less than 0.8%, then the metal is used for the production of rolled metal products.

Examples of decoding some types of steel:

St5Gps3 – third category of group “A”;

Ps – semi-quiet steel;

Carbon content is 0.3%;

Manganese – up to 1%.

05 kp – refers to structural low-carbon steel.

05 indicates a carbon content of 0.05%, the designation kp confirms the category of boiling steel.

60G – high-quality structural steel.

in carbon alloy – 0.6%;

Manganese – 1%.

Steel 25 is classified as high-quality low-carbon steel. Its peculiarity is its low content of harmful elements. Cold-rolled and hot-rolled strips, sheets and much more are made from it.

The marking is indicated by two numbers, indicating the carbon content in the alloy - 0.25%. This category is classified as mild steel.

VStZsp – marking confirms that it belongs to structural carbon steel and belongs to group “B”,

number 3, calm steel.

High-quality structural steel contains small amounts of chemical elements such as phosphorus and sulfur. Other chemical compounds may also be present. The labeling contains numbers that indicate the amount of carbon as a percentage.

Explanation of designations: Automatic steels

This category is marked with the letter “A”. The assortment provides for the production of long rolled metal products in the form of various sections (hexagonal, round, square). It is not recommended to use such metal in the production of welded metal structures.

The following designations for automatic steel are used: A12, A40G, A20 and many others. For example, steel marked A12 is intended for simple structures. Other grades of steel are used for the production of the most critical parts that perform work under high pressure and stress.

AS12ХН refers to automatic alloy steel.

The presence of carbon is 0.12%.

Chromium and nickel – 1% each.

As you can see, deciphering any type of steel is not particularly difficult.

15HSND refers to low-alloy structural steel,

the number 15 indicates that the metal contains 0.15% carbon,

chromium, silicon, nickel and copper 1%.

Low-alloy steel 10khsnd - intended for creating bridges and various types of metal structures, belongs to the category of well-welded metals. Behind the number are letters that indicate what elements are included in the metal.

Steel 10khsnd contains the following elements:

0.9% – chromium,

0.12% – carbon,

0.5% – nickel and copper.

Steels X and HVG are used for the production of measuring instruments. For the production of dies, the following steels are needed: X12M, 9X, 3X2N8F and others.

For the manufacture of impact tools, alloys 5ХВ2С and 4ХС are used.

High speed steels. Steel products are intended for the production of cutting tools, and the marking begins with the letter P. The most popular and popular grades are P9, P18, P12.

Let's look at the following example R6M5F3.

High-speed steel, since the letter P appears first.

Tungsten – 6%.

Molybdenum – 5%.

Vanadium – 3%.

Interpretation of steel 12Х18Н10Т

This category of steel is considered the most popular for the use of welding machines and belongs to the austenitic class, operating in a wide range of temperature conditions. This steel copes well with alkali solutions and acidic environments.

The number 12 indicates the presence of carbon - 0.12%.

X18 shows that the steel contains 18% chromium.

H10 – 10% nickel.

The letter “T” is without a number, so we can conclude that the titanium content in the metal does not exceed 1.5%. As you can see, there are no difficulties in deciphering, you just need to be careful and familiarize yourself with the chemical and physical properties of a particular grade of steel.

Alloy steels with special properties are heat-resistant, heat-resistant and corrosion-resistant steels.

The greatest demand is for chromium-nickel and chromium steels: 30Х13, 95Х18. This type is intended for forging.

Explanation of steel 95x18:

95 – indicates the presence of carbon in steel – 0.95%;

The number 18 indicates the chromium content in steel – 18%.

Steel has increased wear resistance and strength properties. A special use of steel is in the manufacture of knives.

Heat-resistant steel 40Х10С2М. Steel is distinguished by its ability to withstand increased mechanical loads. Wear-resistant steels are highly resistant to any wear. These include: ball bearing, high-manganese and other types of steel.

If the steel is bearing, then it is designated accordingly by the letter “Ш”.

The figure confirms the presence of chromium in percentage terms.

ШХ15 – bearing steel;

Carbon -1%;

Chromium – 1.5%.

Source: https://www.tmk-chel.ru/glavnaya/stati/rasshifrovka-stalej/

Decoding steels, alloys and cast irons: table, examples. Breakdown of steels by composition:

Steel is an alloy of iron and carbon, the content of which does not exceed 2.14%. It has high malleability and rollability, which explains its widespread use in industry, mechanical engineering and other industries.

In metallurgical production, where rolled products differ not only in profile, but also in steel grades, marking each piece of rolled products has long become an indispensable rule. Decoding steels makes it possible to immediately draw a conclusion about the applicability of a given metal for a particular technological operation or for a specific product in general.

Marking is applied to the end of each unit of profiles using the “hot stamping” method in the production flow using so-called stamping machines. The marking contains: steel grade, heat number, manufacturer's mark.

In addition, each workpiece is marked with indelible paint in a combination of colors according to steel groups on cooled workpieces. By agreement of the parties, color markings can be applied to individual profiles in a package in the amount of 1-3 pieces per package.

A package is a bundle of profiles with a total weight of 6-10 tons, packed with rolled wire with a diameter of 6 mm and 6-8 threads.

Alloy steels

The table for decoding steels by composition is presented below.

Designation	Chem. element	Name	Designation	Chem. element	Name
X	Cr	Chromium	A	N	Nitrogen
WITH	Si	Silicon	N	Ni	Nickel
T	Ti	Titanium	TO	Co	Cobalt
D	Cu	Copper	M	Mo	Molybdenum
IN	Wo	Tungsten	B	Nb	Niobium
G	Mn	Manganese	E	Se	Selenium
F	W	Vanadium	C	Zr	Zirconium
R	B	Bor	YU	Al	Aluminum

If the name contains the letter “H”, then the alloying elements include rare earth elements - niobium, lanthanum, cerium.

Cerium (Ce) – affects strength characteristics and ductility.

Lanthanum (La) and neodymium (Ne) - reduce the sulfur content and reduce the porosity of the metal, leading to a decrease in grain size.

Decoding steels: examples

For an example of decoding, consider the common steel grade 12Х18Н10Т.

The number “12” at the beginning of the brand name is an indicator of the carbon content in this steel; it does not exceed 0.12%. Next comes the designation “X18” - therefore, the steel contains the element chromium in an amount of 18%. The abbreviation “H10” indicates the presence of nickel in a volume of 10%. The letter “T” indicates the presence of titanium, the absence of a digital expression means that it is less than 1.5%. Obviously, a qualified decoding of steel by composition immediately gives an idea of ​​its quality characteristics.

If we compare the designations of alloy and carbon steels, this becomes a noticeable difference, indicating the special properties of the metal due to specially introduced alloying additives. Decoding steels and alloys indicates their chemical composition. The main alloying additives are:

• nickel (Ni) – reduces chemical reactivity and improves the hardenability of the metal;
• chromium (Cr) – increases the tensile strength and yield strength of alloys;
• niobium (Nb) – increases acid resistance and corrosion resistance of welded joints;
• cobalt (Co) – increases heat resistance and impact strength.

Alloying - the mechanism of action of alloying elements

It is difficult to decipher steels. Materials science studies this subject comprehensively.

alloying additives in steel can vary widely, depending on what properties need to be imparted to the metal. Thus, nickel and chromium can be present in steel in amounts up to 1%, in some cases more. Molybdenum, vanadium, titanium and niobium - 0.1-0.5%, manganese and silicon - from 1% or more.

The impact of alloying additives in any case is associated with distortion of the iron crystal lattice and the introduction of foreign atoms of a different size into it.

How is it easier to decipher steels (materials science)? The table provides useful information.

Element	Designation	Chem. sign	Influence of an element on the properties of metals and alloys
Nickel	N	Ni	Nickel imparts corrosion resistance to alloys through strengthening the bonds between the nodes of the crystal lattice. The enhanced hardenability of such alloys determines the stability of properties over a long period of time.
Chromium	X	Cr	Improvement in mechanical properties - increased strength and yield - is due to an increase in the density of the crystal lattice
Aluminum	YU	Al	It is fed into the metal stream during casting for deoxidation, most of it remains in the slag, but some of the atoms pass into the metal and distort the crystal lattice so much that this leads to a multiple increase in strength characteristics.
Titanium	T	Ti	It is used to increase the heat resistance and acid resistance of alloys.

Positive aspects of doping

The peculiarities of the properties are most clearly manifested after heat treatment; therefore, all parts made of such steel are processed before use.

1. Steels and alloys improved by alloying have higher mechanical properties compared to structural ones.
2. Alloying additives help stabilize austenite, improving the hardenability of steels.
3. Due to the reduced degree of austenite decomposition, the formation of quenching cracks and warping of parts is reduced.
4. Impact strength increases, which leads to a decrease in cold brittleness, and parts made of alloy steels have higher durability.

Negative sides

Along with the positive aspects, steel alloying also has a number of characteristic disadvantages. These include the following:

1. In products made from alloy steels, reversible temper brittleness of the second type is observed.
2. High-alloy class alloys include retained austenite, which reduces hardness and fatigue resistance.
3. Tendency to form dendritic segregations, which leads to the appearance of stitch structures after rolling or forging. To eliminate the effect, diffusion tempering is used.
4. Such steels are prone to flake formation.

Steel classification

How is steel deciphered by composition? Materials containing less than 2.5% of alloying additives are classified as low-alloyed, with an amount from 2.5 to 10% are considered alloyed, and more than 10% are considered highly alloyed.

m of carbon in the composition of steels is due to their division into:

• high carbon;
• medium carbon;
• low carbon.

The chemical composition determines the division of steels into:

• carbon;
• alloyed.

Cast iron

Cast iron is an alloy of iron and carbon with a content of the latter above 2.15%. It is divided into unalloyed and alloyed containing manganese, chromium, nickel and other alloying additives.

Differences in structure divide cast iron into two types: white (has a silvery-white fracture) and gray (has a characteristic gray fracture). The form of carbon in white cast iron is cementite. In gray - graphite.

Gray cast iron is divided into several varieties:

• malleable;
• heat resistant;
• high strength;
• heat resistant;
• antifriction;
• corrosion resistant.

Designation of cast iron grades

Different grades of cast iron are designed to be used for different purposes. The main ones are the following:

1. Pig irons. They are designated as “P1”, “P2” and are intended for remelting in steel production; cast iron with the designation “PL” is used in foundries for the manufacture of castings; conversion with a high phosphorus content, designated by the letters “PF”; High quality pig material is designated by the abbreviation “PVK”.
2. Cast iron, in which graphite is in plate form - “SC”.
3. Anti-friction cast iron: gray – “ACS”; high strength - “AChV”; malleable - "AChK".
4. Cast iron with nodular graphite, used in foundries, is “HF”.
5. Cast iron with alloying additives, endowed with special properties - “C”. Alloying elements are designated by letters in the same way as for steel. The designation with the letter “Ш” at the end of the name of the cast iron grade indicates the spherical state of the graphite in such a grade.
6. Malleable cast iron – “KCH”.

Decoding steels and cast irons

For cast irons, called gray, the characteristic form of graphite is lamellar. They are marked with the letters SC, the numbers after the letter designation indicate the minimum value of the tensile strength.

Example 1: ChS20 – gray cast iron, has a tensile strength of up to 200 MPa. Gray cast iron is characterized by high casting properties. It can be easily processed by cutting and has anti-friction characteristics. Products made of gray cast iron can dampen vibrations well.

At the same time, they are not sufficiently resistant to tensile loads and do not have impact resistance.

Example 2: HF50 – high-strength cast iron with tensile strength up to 500 MPa. Possessing a structure in the form of spheroidal graphite, it has higher strength characteristics compared to gray cast iron. They have a certain plasticity and higher impact strength. Along with gray cast iron, high-strength cast iron has good casting characteristics, antifriction and damping properties.

These cast irons are used in the production of heavy parts, such as press equipment frames or rolling rolls, internal combustion engine crankshafts, etc.

Example 3: KCh35-10 – malleable cast iron, having a tensile strength of up to 350 MPa and allowing elongation of up to 10%.

Malleable cast irons, in comparison with gray ones, have greater strength and ductility. They are used for the production of thin-walled parts that experience shock and vibration loads: hubs, flanges, engine and machine crankcases, driveshaft forks, and so on.

Conclusion

The breadth of use of metals in industry requires the ability to quickly navigate the properties and capabilities of products. Indicators such as elasticity, weldability, and wear are encountered almost every day in one form or another.

For many decades, the volume of iron and steel production per capita was one of the most important factors in assessing the success of the state. The successful operation of mechanical engineering, automotive industry and many other sectors of the national economy depended, and still depends, on metallurgy. The condition of our only true ally – the army and navy – depends on the availability of a large amount of high-quality metal. Metal serves us on water, under water and in the air.

Source: https://www.syl.ru/article/211640/new_rasshifrovka-staley-splavov-i-chugunov-tablitsa-primeryi-rasshifrovka-staley-po-sostavu

Steel grades, decoding of 30KhGSA by symbols and tables of chemical composition with explanations, metal marking

An alloy of iron and carbon, where the carbon content ranges from 0.1% to 2.14%, is called steel. It is worth adding that the iron content should be at least 45%.

To impart the desired properties during smelting, alloying is carried out, that is, additional additives containing alloying elements are added to the melt. In this way, alloys with desired properties are obtained. All steel grades comply with strictly defined technical standards (GOST). By their writing, you can find out the amount of each element in the alloy, as well as harmful impurities (everything is specified in the corresponding GOST).

Based on the content of carbon and additives (alloying), steels are divided into:

• Low alloyed (contain alloying agents up to 4%).
• Medium alloyed (up to 11%).
• Highly alloyed (over 11%).
• When the carbon content is more than 0.6%, steel is classified as high-carbon.
• Medium-carbon ones have up to 0.55% carbon in their composition.
• Low carbon - no more than 0.25%.

The method of metal deoxidation can be seen in the brand name. It is designated as follows:

• SP (calm), oxygen removed;
• PSP (semi-quiet);
• KP (boiling) is not deoxidized, oxygen has not been removed.

If these designations are absent, then the steel is usually classified as calm (St3sp and St3 are the same thing). Steels of ordinary quality, not alloyed, are designated “St” and a number indicating its upper limit for carbon (0.1%).

Metal remelting methods

Remelting methods are distinguished depending on the steel smelting furnaces in which the metal is melted:

• open hearth;
• oxygen-converter;
• electrothermal.

Electric ones can be plasma, arc, slag and others. These names indicate in which steel-smelting units (furnaces) the metal was smelted. The method of remelting is usually shown at the end of the entire mark, separated by a hyphen. For example, from the name 12Х18Н10Т-ВД it is clear that the alloy contains chromium (X), titanium (T) and nickel (N), vacuum-arc remelting (-VD). Accordingly, 12Х18Н10Т-Ш means slag remelting.

Designation of some smelting methods:

• slag “-SH”;
• arc "-D";
• vacuum-arc “-VD”;
• plasma “-PT”;
• plasma-arc “-P”;
• electron beam “-EL”;
• plasma-beam “-PL”;
• vacuum "-B".

Quality marks

If there is an “A” at the end of the brand name (for example, 50HFA), this means that the steel is high quality with a phosphorus and sulfur content of less than 0.025%. Ordinary quality steels contain up to 0.07% of these impurities, high-quality steels - up to 0.035%. For especially high-quality steels, it is customary to put “Ш” at the end of the mark.

Where the letter is placed on the stamp matters. The “A” in front of all the marks is sulfur, and in the middle of the mark it shows nitrogen.

No matter what plant the metal is smelted at, it has a strictly regulated composition; remelting, accordingly, will have properties specific to that particular brand. Depending on the industrial use, steels are divided into structural steels, structural steels, steels and alloys with special properties.

To mark steels, it is customary to use the designation of the composition in letters of the Russian alphabet and numbers.

Decoding letters

If you look at the table below explaining which letter corresponds to each element, it becomes clear that XNM means that the alloy contains chromium, nickel and molybdenum.

Element	Symbol in labeling	Chemical sign
Nitrogen	A	N
Aluminum	YU	Al
Bor	R	B
Vanadium	F	W
Tungsten	IN	Wo
Cobalt	TO	Co
Silicon	WITH	Si
Manganese	G	Mn
Copper	D	Cu
Molybdenum	M	Mo
Nickel	N	Ni
Niobium	B	Nb
Selenium	E	Se
Titanium	T	Ti
Chromium	X	Cr
Zirconium	C	Zr

Numbers and their absence

The marking may contain numbers. To decipher the steels you need to know what they show. Located after the icon , they indicate the mass fraction of this substance in the alloy.

The first number shows the percentage of carbon. For example, decoding of brand 40Х13: stainless steel contains 0.40% carbon and 13% chromium. Moreover, if the proportion of carbon is shown as a two-digit number, its content is expressed in hundredths of a percent, and one in tenths. The number after the alloying element icon shows its percentage. elements 1.0-1.5% - default if there is no number. Example: 5ХНМ - 0.5% carbon, 0.1% nickel and molybdenum.

What can you learn from a brand?

For steel grade 30KhGSA, the decoding is as follows: high-quality (this is shown by “A” at the end of the grade), contains 0.3% carbon (which corresponds to the first digits), chromium, manganese and silicon - 1% each. Let's check whether the answer corresponds to the GOST 4543–71 standard for structural steels.

It's easy to learn everything about metal from state standards. Steel grades with interpretation in the table will show their full composition. The preamble indicates areas of application and other useful information.

It can be seen that for each steel grade, a table explaining the maximum content of a particular element will help to read the marking. In our case, carbon is in the range of 0.28-0.34; silicon 0.9-1.2; manganese 0.8-1.1; chromium 0.8-1.1.

It happens that you need metal of a similar grade. In this case, a comparative analysis of steel grades is carried out with a breakdown according to the table. For example, there is a melt of 30KhGSA steel with the following parameters: C=0.28; Si=1.0; Mn=0.9; Cr=1.1.

Is it possible to mark metal 25KhGSA, if necessary? It is clear that the content of harmful impurities corresponds to the norm. The answer is clear: yes, the chemical composition fully corresponds to this brand.

Thus, the same melt satisfies the conditions of two different grades.

Special characters

Additional letters are commonly used in some special purpose steels.

Let's list some of them:

• Unalloyed carbon tool ones (U7, U8, U10A, U8GA) contain a number after the letter “U”, it means a tenth of a percent of carbon.
• Bearing ones are immediately visible, they start with “Ш”: ШХ15, ШХ15СГ.
• Steels with improved casting properties are designated “L” at the end: 40ХЛ.
• Pressure vessel metal contains a "K" which indicates how much carbon is in the composition (20K).
• Marking of construction steels begins with “C” and can additionally use “K” - increased resistance to corrosion, “T” - heat-resistant rolled steel (C390K).
• High-speed tungsten-containing grades begin with “P”: R9K5, R18. The number after "P" indicates the tungsten content. If vanadium in them is more than 2.5%, then its content is indicated: P6M5F3 (3%). Chromium and carbon have standard values ​​and are therefore not shown.
• It is worth mentioning the steels used for surfacing wire. They are designated at the beginning of the brand with the “NP” icon, for example, NP30ХGSA.

We can say that if any controversial issues regarding labeling arise, the answer can be found in the corresponding GOST or TU.

Before smelting any grade of metal, the charge materials are calculated. Then the desired composition is poured into the oven, boiled and poured. All necessary elements are verified using a ladle sample in accordance with GOST or TU tables. They check for harmful impurities (they get into the melt with the charge and from the lining). If all components are within the normal range, then the melt is marked as expected.

It also happens that chemical composition standards are not met. Then the metal is marked with a different brand. The customer must be sure that he will receive exactly the products he ordered. The quality of the products depends on this. 's technical control system strictly monitors this.

Source: https://tokar.guru/metally/stal/markirovka-stali-marka-30hgsa-rasshifrovka-s-razyasneniyami.html

Decoding of steel and alloy grades EP, EI (3P 333, EI 869) - MetallProiKomplekt

 / Directory / Decoding steel grades, letter values. Special steels and alloys. EP, EI (3P 333, EI 869)

Decoding of steels, letter meanings of steel grades.

The main standard defining the basic chemical composition, the letter designation of alloying components present in steel is indicated in GOST 4543-71 “Rolled products from alloyed structural steel”. Today, various steels are produced with the addition of components not regulated by this GOST 4543-71; they are often designated by the first letter of the element name, with some exceptions.

 Letter designations of steel condition

SP - Calm steel

PS-Semi-quiet steel

KP-Boiling steel

 Ordinary quality unalloyed steel is designated, for example, steel 3, steel 3sp (mild steel)

High-quality structural non-alloy steel is usually designated as st. 10-st. 45 (also st. 20, st. 35, st. 40, the two-digit number of this steel indicates the carbon content in the steel (for example, steel 45 carbon content is 0.45%)

Low alloy steel is usually designated as 09G2S, 10G2, 10HSND-15HSND. Steel 09G2S is conventionally deciphered as follows: 09G2S - 09 means carbon content of 0.09%, 09G2S - G2 means the presence in the steel of the alloying element manganese, the content of which is at least 2.5%, 09G2S - C means silicon content.

For steel 10ХСНД and 15ХСНД, numbers after the letters are not written, because the average content of alloying elements is not less than 1%.
Also, low-alloy steels are designated by the letter C - construction steels with the corresponding minimum yield strength, S-345, S-355, (there are also S-355T, the letter T means heat-strengthened steel.

If the letter K , this means increased resistance to corrosion.

Structural spring steel, these are steels such as 65G-70G, 60S2A, 60S2FA. For example, steel 65G means a carbon content of 0.65% and the alloying element is G-Manganese

Structural alloy steel , usually grades such as 15X-40X (also st. 20X, st. 30X), for example steel 40X means carbon content, the letter X is the alloying element chromium. Let us also use chrome-silicon-manganese steel 35KhGSA as an example; the steel has increased resistance to impact loads and is a very strong steel. For example, steel 35KhGSA contains carbon equal to 0.3% as well as alloying elements X-Chrome, G-Manganese, C-Silicon, A-Nitrogen of approximately 1.0%.

The letter A at the beginning of the designation of the steel grade indicates that this Automatic steel, for example A12, AS12HN, AS14, AS19HGN, AS35G2, is mostly used in the automotive industry, for processing on specialized machines with high cutting speeds. The letter A at the end of the steel marking classifies it as high-quality steel. For example, 40KhGNM belongs to high-quality steels, and 40KhGNMA already belongs to high-quality ones.

Steel Boiler room this brand is called a boiler room, it works under high pressure, this steel is also structural, for example 20K, 20KT, 22K, the average carbon content in it is 0.20%

 Structural ball bearing steel, for example, such as ShKh-15, ShKh-20. The designation of ball bearing steel begins with the letter Ш. There is also an alloy of steel ШХ15СГ, the letters SG mean a high content of silicon and manganese, which gives the steel the best characteristics. For example, steel ШХ15 stands for the letter Ш - ball bearing steel, X indicates a chromium content of about 1.5%.

Tool steel . Typically, tool steel grades such as U7, U8, U10 are classified as high-quality tool steels, and steel grades such as U7A or U8A, U10A are classified as high-quality tool steels. They are designated by the letter Y, and the number indicates the carbon content.

High speed steel . Quick cutter short name. It is designated by the letter P, for example, P9, P18 or P6M5, the number following the letter P indicates the content of the element B-tungsten.

For example, steel R6M5K5 indicates the following R- high-speed, number 6 tungsten content , M5 indicates molybdenum content , K5 indicates the content of K-cobalt R6M5K5 . Carbon is not indicated because its content is always about 4.5% in all high-speed cutters.

If the vanadium content is higher than 2.5%, then the letter F for example R18K5F2. 

Electrical steel is of the same grade as 10880-20880. Steel contains a minimum amount of carbon, the percentage being less than 0.05%, which is why it has a low electrical resistivity.

For example, grade 10880 is deciphered as follows: number 1 indicates the rolling method, hot-rolled or forged (number 2 at the beginning means calibrated steel). The next number 0 indicates that the steel is unalloyed, without an aging factor; if the second number is 1, it means steel with a standardized aging factor.

The third digit means the group according to standardized characteristics. The fourth and fifth numbers mean the quantity according to the standardized characteristics.

Casting steels have the letter L at the end of the grade and are designated in the same way as structural steels, for example 110G1L GOST 977-75, 997-88

Aluminum alloys are designated by the letter A, for example AMG, AMTs, AD-1N (D means duralumin, N means cold-worked),

The steel is high quality, different manufacturing methods are used to make high quality steel.
Electroslag remelting is designated by the letter Ш at the end of the value, for example: stainless steel 95Х18-Ш, 20ХН3А-Ш.

Vacuum arc remelting is designated at the end of the value by the letters VD for example EP33-VD.
Electroslag remelting followed by vacuum-arc remelting is designated SHVD .
Vacuum induction melting has the designation VI.

Electron beam remelting has the letter designation EL.
Gas-oxygen refined remelting has the value GR.

Source: http://mpkural.ru/rasshifrovka_marok_staley_i_splavov

Steel St2kp - carbon steel of ordinary quality

Number 2 - indicates the serial number of the grade, and not the average carbon content in it
kp - boiling (the kp index indicates the degree of deoxidation)
If a number is not indicated after the letter index, then the steel is of the 1st category . Standardized indicators: tensile strength and relative elongation.

Type of delivery

Long products, including shaped steel: GOST 2590-88, GOST 2591-88, GOST 8239-89, GOST 19772-93, GOST 19771-93, GOST 8278-83, GOST 8281-80, GOST 8283-93, GOST 380 -94, GOST 8509-93, GOST 8510-86, GOST 8240-89, GOST 535-88, GOST 2879-88. Thick sheet GOST 19903-74. Thin sheet GOST 19903-74, GOST 16523-89. Tape GOST 503 -81. Strip GOST 103-76, GOST 82-70. Wire GOST 3282-74, GOST 17305-91.

Pipes: GOST 10705-80, GOST 10706-76, GOST 3262-75.

Purpose

Non-critical parts with increased ductility, lightly loaded elements of welded structures operating under constant loads and positive
temperatures.

Temperature of critical points, °C

Ac1	Ac3	Ar3	Ar1
735	854	835	682

C, carbon	Mn, manganese	Si, silicon	P, phosphorus	S, sulfur	Cr, chromium	Ni, nickel	Cu, copper	As, arsenic
no more
0,09-0,15	0,25-0,50	0,07	0,04	0,05	0,30	0,30	0,30	0,08

GOST	Delivery status	Section, mm	σ0.2, MPa	σв, MPa	δ5(δ4), %
no less
380-94	Hot rolled products	Until 20Sa. 20 to 40St. 40 to 100St. 100	215205195185	320-410	33323030
16523-89 (Transverse samples)	Hot rolled sheetsCold rolled sheets	Up to 2.0 incl.St. 2.0 to 3.9 incl. Up to 2.0 inc. St. 2.0 to 3.9 incl.	—	320-410	(21)(23)(24)(26)

Delivery status	KCU, J/cm2, at temperature, °C
+20		-20	-40
Hot rolled rod with a diameter of up to 150 mm	24-64	13-16	8	8

NOTE. At σв = 323-412 MPa, endurance limit σ-1 = 176-196 MPa

Technological characteristics

Forging temperature, °C: beginning 1300, end 750. Cooling in air.

Weldability - weldable without restrictions; welding methods: RDS, ADS under submerged arc and gas shield, ESW and KTS. For thicknesses greater than 36 mm, preheating and subsequent heat treatment are recommended.

Cutting machinability - Kνb. st = 1.6 and Kνtv. spl = 2.0 in the hot-rolled state at HB 137.

Flock sensitivity - not sensitive.

Tendency to temper brittleness - not prone.

Source: http://enginiger.ru/materials/uglerodistye-stali/stal-st2kp-uglerodistaya-obyknovennogo-kachestva/

Decoding steel markings online

Steel grades are a classification of steels according to their chemical composition and physical properties. In Russia, the USA [1], Europe [2], Japan [3] and China [4], various marking methods are used for similar steels.

Types of steels [edit | edit code]

Steel is an alloy of iron and carbon, the latter content in it being no more than 2.14%, and iron content more than 50%. Carbon gives the alloy hardness, but if it is in excess, the metal becomes too brittle.

One of the most important parameters by which steels are divided into different classes is the chemical composition. Among the steels according to this criterion, alloyed and carbon steels are distinguished, the latter are divided into low-carbon (carbon up to 0.25%), medium-carbon (0.25-0.6%) and high-carbon (they contain more than 0.6% carbon).

Steel is subject to mandatory marking.

To clarify information on a specific steel grade, so-called grade markers can be used. 2nd (2003) and 3rd (2011) editions of the “Marker of Steels and Alloys”, ed. A. S. Zubchenko contain a description of about 600 grades of steels and ferrous alloys, the 4th (2014) edition - more than 700 grades [5].

Alloy steels, in contrast to unalloyed steels, have a slightly different designation, since they contain elements that are specially introduced in certain quantities to provide the required physical or mechanical properties. Eg:

• chromium (Cr) increases hardness and strength
• Nickel (Ni) provides corrosion resistance and increases hardenability
• Cobalt (Co) improves heat resistance and increases impact resistance
• Niobium (Nb) helps improve acid resistance and reduces corrosion in welded structures.

Marking of steel elements [edit | edit code]

Labeling nameNameCharge number of the atomic nucleusElement designation

L	Beryllium	№ 4	Be
R	Bor	№ 5	B
A	Nitrogen	№ 7	N
Sh	Magnesium	№ 12	Mg
YU	Aluminum	№ 13	Al
WITH	Silicon	№ 14	Si
P	Phosphorus	№ 15	P
T	Titanium	№ 22	Ti
F	Vanadium	№ 23	V
X	Chromium	№ 24	Cr
G	Manganese	№ 25	Mn
TO	Cobalt	№ 27	Co
N	Nickel	№ 28	Ni
D	Copper	№ 29	Cu
Gl	Gallium	№ 31	Ga
E	Selenium	№ 34	Se
C	Zirconium	№ 40	Zr
B	Niobium	№ 41	Nb
M	Molybdenum	№ 42	Mo
CD	Cadmium	№ 48	Cd
IN	Tungsten	№ 74	W
And	Iridium	№ 77	Ir
AC	Lead	№ 82	Pb
In and	Bismuth	№ 83	Bi
H	Rare earth metals	—

Marking of steels in Russia [edit | edit code ]

Deciphering steel grades requires knowing what letters are used to denote certain chemical elements that make up the grade or alloy.

If at the very end of the mark there is a letter A, then this means high-quality steel, the content of phosphorus and sulfur in which is minimized (S [6]:

• "kp" - boiling
• "ps" - semi-calm
• "sp" - calm

Non-standard steels are designated differently. Thus, experimental grades smelted at the Elektrostal plant are designated by the letter I (research) and P (trial) and a serial number, for example, EI179, EI276, EP398, etc. Experimental grades smelted at the Dneprospetsstal metallurgical plant denote CI 80, where D is the manufacturing plant, I is research, 80 is the serial number assigned to the steel grade.

An example of deciphering the steel grade 12Х18Н10Т [edit | edit code]

12Х18Н10Т is a popular steel (corrosion-resistant, heat-resistant austenitic class), which is used in welding machines and vessels operating in dilute acid solutions, in solutions of alkalis and salts, as well as in parts operating under pressure at temperatures from −196 °C up to +600 °C [7] .

The two numbers at the very beginning of the alloy steel grade are the average carbon content in hundredths of a percent. In this example the carbon content is 0.12%. If instead of two numbers there is one, then it shows how much carbon (C) is contained in tenths of a percent. If there are no numbers at the beginning of the steel grade, then it contains 1% carbon or more.

The letter X and the number 18 following it indicate that this brand contains 18% chromium. The ratio of an element in fractions of a percent expresses only the first number at the beginning of the mark, and this applies only to carbon. All other numbers in the brand name express the number of specific elements as a percentage.

Next comes the H10 combination, which is 10% nickel.

At the very end there is the letter T without any numbers. This means that the content of the element is low, usually about 1% (sometimes up to 1.5%). In this grade of alloy steel, the amount of titanium does not exceed 1.5%.

So, steel grade 12Х18Н10Т (structural cryogenic, austenitic class) contains the following information: 0.12% carbon, 18% chromium (X), 10% nickel (N) and a small titanium content (T), not exceeding 1.5%.

Source: https://MyTooling.ru/instrumenty/rasshifrovka-markirovki-stali-onlajn