How to determine steel grade

How to determine steel grade at home

Steel grade definitions

High-precision methods for determining the grade of steel and alloys

To accurately determine the alloy grade, two important components are necessary:

• qualitative and quantitative chemical composition glory;
• alloy hardness.

Having such data, you can determine the grade of almost any alloy, since the classification of alloys is based on them.

So the chemical composition of the alloy allows you to determine the base metal, the degree of alloying and the general properties of the alloy.

And the hardness of the alloy makes it possible to distinguish between alloys of the same chemical composition, but with different additional processing of the metal or with different smelting techniques.

Since alloys with the same chemical composition and different properties are extremely rare, in most cases an accurate determination of the alloy composition is sufficient.

Determining the chemical composition of an alloy consists of determining the base metal and determining alloying additives (metallic and non-metallic in nature).

The most accurate and fastest method for determining the content of base metal and alloying components of a metallic nature in an alloy is X-ray fluorescence analysis (X-ray fluorescence spectrometry, XRF, XRF, RFSA). In addition, the advantages of this method include indestructibility and the ability to analyze extremely small samples.

The XRF method makes it possible to identify and determine the content of elements from Cl (17) to U (92) in alloys.

To determine the content of elements such as Li, Be, B, N, O, F, Na, Mg, Al, Si, P, S in alloys, the XRF method in an inert gas environment is used.

The determination of C content in alloys is carried out by automatic coulometric titration based on pH value.

Inaccurate (approximate) methods for determining the grade of steel and alloys

If the grade of steel is unknown, you can approximately determine the quality of the steel by fracture and by test cuts.

The crystalline structure at the fracture site of the steel can be used to judge its strength: the thinner the crystalline structure, the higher quality the steel.

During test cuts, low-hardness steel is filed with any file (including a garnish file), medium-hard steel with a personal and velvet file, and high-hardness steel with only a velvet file.

You can more accurately determine the grade of steel by the resulting beam of sparks on the emery wheel. The shape and length of the spark threads, the color of the sparks and the number, width of the spark beam are different for different grades of steel. By testing standard steel samples for spark, you can learn to recognize steel grades.

Below is a description of the shape of spark beams for some steel grades:

• low-carbon steel - uniform, continuous straw-yellow threads of sparks with a small number of stars;
• carbon steel with a carbon content of about 0.5% - a bunch of light yellow threads of sparks with stars at the end;
• tool steel U7-U10 - a diverging bunch of light yellow threads of sparks with an increased number of stars at the end;
• tool steel U12, U13 - a dense and short bunch of light threads of sparks with a very large number of stars at the ends of the threads, while the stars are more branched;
• steel containing chromium - a dense bunch of dark red threads of sparks with a large number of yellow stars at the ends of the threads, the stars are highly branched;
• high-speed steel containing chromium and tungsten - a bunch of intermittent dark red threads of sparks, at the ends of which there are lighter drop-shaped stars;
• spring steel containing silicon - a wide bunch of dark yellow threads of sparks, at the ends of which small stars of a lighter color are formed;
• high-speed steel with a cobalt additive - a wide bunch of dark yellow threads of sparks without stars at the end.

Without issuing a protocol with a stamp - 650 UAH/request, if everything is official - 2000 UAH.

Determination of carbon content in alloys

Carbon analysis methods (determination of carbon content in alloys)

Carbon in steels and alloys is analyzed by various methods: an OES100 spark optical emission spectrometer or the combustion method with an infrared analyzer. Carbon can also be analyzed by X-ray fluorescence spectrometer, laser optical emission spectrometer and other methods.

Carbon analyzer AN-7529

Express carbon analyzer AN-7529 is designed to determine the mass fraction of carbon in steels and alloys using the method of automatic coulometric titration based on pH value, for marking analyzes of carbon in products and raw materials of metallurgical and metalworking enterprises.

The AN-7529 express carbon analyzer is used to carry out analyzes in the laboratories of enterprises and research institutions in various industries.

The analyzers are designed for continuous round-the-clock operation in factory laboratories at ambient temperatures from 10 to 35C, relative humidity up to 80% and meet the requirements for group 2 devices.

Measurement characteristics

Measured carbon concentration ranges: 0.03-9.999%

Certification

Without issuing a protocol with a seal – 950 UAH/issue, official conclusion from – 2600 UAH.

If you need to determine the steel grade, please contact Us

Source: https://steelfactoryrus.com/kak-opredelit-marku-stali-v-domashnih-usloviyah/

Steel marking: what it depends on and how it is marked, a table with a breakdown of metals and alloys

December 25, 2019 7 minutes to read520

Any craftsman who works with metal products knows what a “steel grade” is. Deciphering it allows you to get an idea of ​​the chemical composition and physical parameters, which is fundamental information for creating any objects made of metal.

Many people believe that marking steel and rolled metal products is a complex process that requires special knowledge. However, despite the apparent complexity, it is quite simple to understand.

To do this, you only need to know the principle of its compilation and how it is classified, which this article will tell you about.

The alloy is marked with letters and numbers, making it possible to determine the presence of chemical elements and their volume as accurately as possible. Based on this data, as well as knowledge of how different chemicals interact with the metal base, it is possible to understand with maximum accuracy what technical properties relate to a particular steel grade.

Types of steels and features of marking

Steel is an iron-carbon alloy, the amount of which does not exceed 2.14%. The carbon component is necessary to achieve hardness, but it is extremely important to monitor its concentration. If it exceeds 2.2%, the metal will become very brittle, making it almost impossible to work with.

By adding any alloying elements, the required characteristics can be achieved. It is by combining the type and volume of additives that grades are obtained that have better mechanical properties and resistance to corrosion. Of course, quality indicators can be improved through heat treatment, but the use of alloying additives significantly speeds up this process.

The basic classification criteria are the following indicators.

• Chemical composition.
• Purpose.
• Quality.
• Structure.
• Degree of deoxidation.

What does the marking show?

In order to decipher the specified information, you do not need to have professional skills or special knowledge. Structural steel, which is of normal quality and also does not contain alloying elements, received the “St” mark.

The number below reflects the amount of carbon. After them there may be the letters “KP”, which indicate unfinished deoxidation in the furnace, therefore such an alloy is considered boiling.

If there is no such abbreviation, then he is considered a calm type.

Marking and classification of steel by chemical composition

As mentioned earlier, one of the main divisions of this metallic material is based on its chemical composition. The basic components of the material are reinforced concrete and carbon (its concentration is less than 2.14%). Based on the concentration and proportions of additives used, iron accounts for at least half the volume.

Based on the level of carbon content, steel products are divided.

1. Low-carbon - carbon no more than 0.25%.
2. Medium carbon - from 0.25 to 0.6%.
3. High carbon - from 0.6%.

Increasing the carbon component helps to increase metal hardness, but at the same time reduces its strength. To improve the performance of alloys, various chemical elements are added to them, after which they are converted into alloy steels. They come in three types.

1. Low alloyed - the volume of additives is less than 2.5%.
2. Medium alloyed - 2.5-10%.
3. Highly alloyed - can reach 50%.

Source: https://www.cleverence.ru/articles/auto-busines/markirovka-stali-ot-chego-zavisit-i-kak-markiruetsya-tablitsa-s-rasshifrovkoy-metallov-i-splavov/

How to determine steel grade at home? — Machine tools, welding, metalworking

How to distinguish one steel grade from another if, for example, AISI 304 and AISI 303 sheets were stored together? A number of simple, inexpensive and non-damaging tests can help solve this problem. It should be noted right away that such tests have a number of serious limitations.

For example, such tests will not help determine which of two sheets of steel of the same grade has been heat treated and which has not. Additionally, there is no easy way to distinguish certain grades of steel from each other. For example, it is impossible to distinguish steel AISI 304 (08Х18Н10) from AISI 316L (03Х17Н14М3), or 304 (08Х18Н10) from 304L (03Х18Н11).

A molybdenum content test will help determine whether molybdenum is present in steel, but without additional information the grade of steel cannot be correctly determined. For example, AISI 316 (10Х17Н13М2) steel, based solely on the results of this test, can be defined as 316L (03Х17Н14М3), 2205 or 904L.

Often, only with the help of more complex tests, in which the metal is exposed to chemical reagents, strength or heat resistance is checked, can the grade of steel be reliably determined. If simple tests do not help, then a full spectral or chemical analysis in the laboratory cannot be avoided.

Reaction to magnet

This test will help determine that austenitic steels (for example, AISI 300 series) do not react to a magnet when approaching it. Other stainless steels, such as ferritic, martensitic and duplex, react to magnets. When performing this test, it should be remembered that some austenitic steels, for example, 304 (08Х18Н10), can be attracted by a magnet if they were produced by cold rolling.

Reaction to nitric acid

Helps differentiate carbon steel from stainless steel. First, you need to place a steel sample in a solution of nitric acid (from 20-50%) at room temperature, or drop the solution onto a clean steel surface.

A reaction will begin on the surface of the carbon steel, releasing caustic brown vapor. This reaction does not occur with stainless steel.

When working with nitric acid, you must be extremely careful, and you should not inhale the vapors released during the reaction.

Molybdenum content test

Helps determine whether steel contains molybdenum. Steel containing sufficiently molybdenum, for testing as follows: 316 (10x17n13M2), 316L (03x17N14M3), 444, 904L, 2205, all "super -duplicate" alloys (S32760, Zeron 100, S32750, 2507, S32550, S32520, UR52N+). The test can also determine molybdenum in other steels containing approximately 2% Mo.

When conducting a test, it is best to compare an unknown steel with a control sample, for example, AISI 304 (08Х18Н10) and AISI 316 (10Х17Н13М2) steels. For the test you will need an acid-based reagent (you can use either the American “Decapoli 304/316” or “Moly Drop 960”, or domestic analogues, although they are quite difficult to find).

First, it is necessary to prepare the surface of the test sample by cleaning it with sandpaper. Then drop the reagent onto the surface of the steel to be determined and onto the control sample. Dark yellow spots appearing after 2-4 minutes indicate the presence of molybdenum. When carrying out the test, do not forget that its reliability may be affected by the temperature of the samples.

For example, some steels containing about 0.5% molybdenum in impurities may react positively to the test at low temperatures. During the test, you should be careful when working with the reagent and follow the requirements for safe work with acids.

Sulfur content test

Sulfur is a harmful impurity that causes brittleness of steel during hot forming. This test helps determine the level of sulfur in steel. For this test, control samples of AISI CS1020, S1214, 304 or 303 steels will be needed, comparison with which will help in determining the degree of sulfur content.

To carry out the test, it is necessary to clean the surface of the test sample using sandpaper, and control samples should be prepared in the same way.

Next, you should soak the photographic paper in a 3% sulfuric acid solution for 3 minutes, apply the photographic paper face to the surface of the test sample, hold for 5 seconds and compare the results of the tested steel and the control samples. A dark brown stain indicates high sulfur content.

When testing, it should be taken into account that the reliability of the result is seriously influenced by the density and duration of contact of the paper with the surface. When performing this test, also remember to be careful when working with acid.

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Source: https://stanki-info.com/kak-opredelit-marku-stali-v-domashnih-usloviyah/

How to determine the composition of a metal?

Having selected used tools (needles, files, rasps, braids, etc.), first of all you should determine what grade of steel they are made of. To keep your search as limited as possible, you should know what types of steel a particular tool is made from.

Thus, files can be made of both tool carbon steel (U10, U11, U12, U13) and alloy steel (ShKh6, ShKh9, ShKh15). You can learn more about this from the list of tools below.

The files presented in the KovkaPRO assortment are made of high-alloy steel with a hardness of 64-66HRC

Products made of tool and alloy steel:

Files - U10, U11, U12, U13, ШХ6, ШХ9, ШХ15 Needles - U10, U11, U12 Rasps - U7, U7AShabers - U10, U12 Chisels, chisels - U7, U8 Taps - U10, U11, U12, P9, 9ХС, Р18 Wood drills - 9xsewrla for metal -r9, P18 Exverts-P9, P18, 9XS cutters-P9, P18 Zubila, screwdriver-U7A, U8A, 7XF, 8XFPROPERS-U8 Acernerers-U7A, 7XF, 8XFSHEVENENETEN NE7A, U8APILA-U8 Gapolotnita Rules-UN U8GA, U10 Hacksaw blades – U8, U8A, U9, U9A, U10, U10A, U11, U12 Metal shears – U12AMhammers and sledgehammers – U7, U8 Axes – U7 Scythes, sickles – U7, U8 Forks, teeth (peckers) – U7, U8 rakes

Blacksmith tools – U7, U8

Stage 2: determination of carbon content in steel

How can you determine specifically whether, for example, a file is made of carbon or alloy steel? To do this, you should resort to a simple old method. Craftsmen noticed that small metal shavings obtained when processing metal with an abrasive wheel, when heated, produce a sheaf of sparks, which have their own characteristic features for each metal.

The “straws” that make up a sheaf of sparks, each brand has its own special ones: long, short, continuous, intermittent, heaped and sparse, smooth or thickened; from each of them small bright stars can be separated, sometimes very abundantly; The brightness of the glow of the sheaf of sparks is taken into account, as well as color shades - from light yellow to dark red.

The higher the carbon content in the steel, the more bright stars there are in the sheaf of sparks. If the steel contains a little carbon, for example about 0.12%, then the sparks coming out from under the abrasive disk will fan out in the form of slightly curved lines of yellow-straw color, with thickenings in the middle and at the end (1, see Fig. on page 105).

Steel containing 0.5% carbon and having an average hardness produces approximately the same sparks, but a small number of stars separate from the place of average thickening (2). Copious sparks with stars (3) are released from the high-carbon tool steel.

Chromium steel has long, orange-red sparks; from them, like thin branches from the main branch, short sparks with stars at the end extend from them at different angles (4). Tungsten steel sparks intermittently, and also has small thickenings at the end (5).

Chrome-tungsten high-speed steel produces both short and long sparks of a dark red color with thickenings at the end (6).

Stage 3: Tool Test

Now let's get back to the file. Before you start testing it, you must wear safety glasses and place a sheet of black-painted plywood near the sanding wheel. On a black background, the sparkling metal is visible much more clearly, and the eyes have to strain less.

If we forcefully run a file over the emery wheel and get abundant sparks of a bright yellow color with many stars separating from them, we can conclude that it is made of high-carbon tool steel (U10-U13). Conversely, a sheaf of orange-red long sparks with branches and stars at the end indicates that the file is made of alloy steel (ШХ6, ШХ9, ШХ15).

Of course, in this way only the approximate chemical composition of steel is determined, but for amateur practice this is quite enough. Knowing that the file is made of tool steel of the indicated grades, the heat treatment mode is determined from the table.

The table shows that the U11-U13 steel from which the file is made is annealed at a temperature of 750°C and then gradually cooled in air. Annealing is carried out in a muffle furnace, forge or in the firebox of a conventional furnace.

It is convenient to anneal metal objects in an electric school muffle furnace, since the built-in thermometer makes it possible to monitor the heating temperature. But the depth of the muffle furnace is limited.

If the file does not fit into it, it is wrapped in several layers of tarpaulin and broken with a strong blow of a hammer.

The broken file is removed from the tarpaulin, annealed in a muffle furnace, and then slowly cooled. The resulting scale often interferes with machining. Therefore, wearing glasses and mittens, they knock it down with a hammer and a chisel.

Annealed and processed tool steel becomes quite soft: it can be easily filed, sawn and forged. With minimal hardness, it has maximum plasticity and viscosity. This makes it possible to make from it gravers for engraving, embossing, chisels, cutters, punches, and other tools for the artistic processing of metal.

Having made the desired tool from a file, it is hardened by heating according to the table to 780°C, followed by cooling in water. After hardening, the steel becomes brittle, so it is tempered: heated to 180°C and cooled in water or machine oil. When tempering, the heating temperature of the metal is controlled by the so-called tarnish colors, which correspond to a certain heating temperature.

Source: https://kovkapro.com/kovka-tehnologiya/kak-opredelit-sostav-metalla-test-po-napilniku/

How to determine steel grade at home - Metals, equipment, instructions

There are simply a huge number of different steel options, each grade is characterized by its own specific features. If the manufacturer has not carried out markings, then you can find out the characteristics of the metal only by independently conducting various tests. We'll talk about this in more detail later.

How to determine steel grade

Methods for determining steel grade

A fairly common question is how to determine the grade of steel. There are several common methods:

1. The first involves removing chips from the surface, for which a chisel can be used. At high carbon concentrations it will be short and brittle. A decrease in the indicator causes an increase in plasticity. However, it is not possible to accurately determine the brand using this method.
2. The second method involves hardening the product, after which it is necessary to make cuts. If the material is simply sawed before and after hardening, then it contains a small amount of carbon. Due to the increase in carbon concentration after treatment, the surface becomes too hard.
3. Determining the steel grade by spark is based on a visual inspection of the sparks that are formed when processing the surface with a grinding wheel. With an increase in the size of the sparks and their number, the hardness index increases, which depends directly on the carbon concentration. Such a test does not give an accurate result, since the main characteristics of the flying chips depend on the force of pressing and some other points. You can find tables that decipher the qualities of a material based on chips.

Spark test methodDevice for determining steel grade

You can also determine the brand by the color of the sparks produced. For this purpose, special tables were compiled. The test can be carried out at home only if the lighting is correct.

However, it is impossible to accurately identify the material in this way.

The option with alloying elements can also be identified by other performance characteristics, for example, resistance to high humidity or strong magnetism.

General concepts about steel grades

In the CIS, the applied designation standards are characterized by the fact that they can be used to indicate the main elements. When considering the issue of decoding the brand, we note the following points:

1. The abbreviation “St” is often used. In other cases, no abbreviations are used at all, only numbers.
2. In most cases, the first number indicates the carbon concentration. The following can be used to indicate the amount of alloying components.
3. The composition may include alloying components that significantly change the properties of the material. An example is the inclusion of chromium, which increases resistance to high humidity.

Classification of steels by purpose

Labeling is deciphered using tables that indicate the designation of the chemical element.

Marking of steels according to international and CIS standards

In order to decipher a brand, you can use a variety of standards. Some alloys are designated by certain symbols that indicate the purpose of the metal.

An example is the following points:

1. The letter “Ш” is used to designate metals that are used to make bearings. They are characterized by increased wear resistance.
2. High-quality alloyed workpieces are designated by the letter “L”. Often the symbol is indicated at the end.
3. “T” is used to designate heat-strengthened rolled products.
4. High corrosion resistance of the workpiece is determined by the letter “K”.
5. If copper is included in the composition, then the symbol “D” is used when indicating the brand.
6. Instrumental can be identified by the letter “U”. They are often used in the manufacture of various tools that are characterized by high wear resistance.
7. The symbol “P” is indicated to designate alloys that contain tungsten. Such a substance significantly increases the heat resistance of the structure.

By deciphering the brand, you can determine which chemical elements are included in the alloy. The numbers in most cases indicate the concentration, symbols, type of alloy and specific chemical elements.

European steel marking system Carbon steel grades according to GOST and ISO international standards

In conclusion, we note that there is simply a huge number of products on sale; in many cases, the brand is affixed by the manufacturer. It is almost impossible to independently determine the composition without the use of special equipment.

, please select a piece of text and press Ctrl+Enter.

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Source: https://spb-metalloobrabotka.com/kak-opredelit-marku-stali-v-domashnih-usloviyah/

Products – Tekhmashholding – group of companies, official website

There are simply a huge number of different steel options, each grade is characterized by its own specific features. If the manufacturer has not carried out markings, then you can find out the characteristics of the metal only by independently conducting various tests. We’ll talk about this in more detail later. How to determine the grade of steel

Steel grades - explanation, types, table with explanations

When starting to create a product, designers develop its design, select steel grades, and analyze them based on their properties. The mechanism is required to be able to operate under given conditions. Considering the structure in dynamics, they try to establish what loads will arise in one or another part.

Based on the calculations, the requirements for the strength of the elements are determined. Then a material is selected that can experience repeated loading, as well as abrasive effects. The higher the load, the less choice the designer has.

The result of the design is the creation of a real prototype in metal, it is tested according to methods accepted in the industry. If necessary, the selection of steels used at the design stage is adjusted.

 In practice, the most common materials used to create machines, devices and complex mechanisms are steel.

General characteristics of steel

Metallurgists determine the condition for the existence of steel - this is the presence in the mechanical mixture of iron and carbon of no more than 2.14% C. Alloys with a high concentration are called cast iron.

Of all the metals, the alloy of iron and carbon has the most attractive properties. This material is used to make:

• vehicle bodies, transmissions and power units;
• metal frames, reinforcement and other systems that ensure the strength of buildings;
• tools, machine components and mechanisms.

The versatility of using steel is explained by the wide possibilities in regulating its properties. They can be adjusted to adapt to create devices that perform different tasks. Even the best weapons are made using this versatile metal.

To date, several thousand steel variants have been developed. But in real practice, about a dozen basic types are more often used, the rest are created to solve special problems. They are used quite rarely.

Steel classification

To understand the markings, you need to understand how steel alloys are classified according to their intended purpose. It is customary to determine properties according to several parameters:

1. The chemical composition determines the strength indicators. Here the properties are determined by the compositional ratios between iron and carbon. Along the way, changes in characteristics depend on the presence of alloying elements or substances that impair performance.
2. The structure changes depending on the production methods. Forged products are stronger, cast ones may form pores or other defects. When rolling through rollers, hardening is achieved and the desired shape is obtained.
3. For proper use, certain brands are determined by their intended purpose. Such information is especially important for special-purpose steels. In them, even small changes in the chemical composition can significantly change the behavior under load or operation in an aggressive environment.
4. The quality of steel ingots depends on the content of harmful components. Sulfur and phosphorus lead to cold brittleness and red brittleness, so metallurgists try to remove deteriorating ingredients from the alloy.
5. Oxygen in steel products changes the structure. To remove it, deoxidizers are added to the molten mass; they form oxides and do not cause negative changes to the metal.

Classification of steels according to main indicators

Classification by structure

The structure is studied on special thin sections. They are examined under a microscope, having previously treated the polished surface with sulfuric acid. It is customary to define the following states:

• Hypoeutectoids are characterized by a high ferrite content. Low carbon content does not allow the metal to exhibit sufficient resistance under mechanical loads;
• eutectoid correspond to the best ratio between strength and plastic properties;
• hypereutectoid steels are used in the manufacture of tools. They are distinguished by high surface hardness, as well as resistance to loading;
• ledeburite contain carbides. The metal exhibits excessive fragility;
• Ferritic indicators correspond to the properties inherent in pure iron.

Eutoctoid steel

Hypoeutectode steel

Ledeburite. Iron carbide inclusions are visible

To improve properties, normalization is carried out. It consists of relieving stress from parts that have had heat treatment associated with improved properties. Prolonged heating and holding at temperatures above 720750 °C, and subsequent cooling leads to annealing. Metal grains change their appearance.

The top row shows the sections before normalization, and the bottom row shows them after

Structural steels

Conventional steels contain carbon. The presence of alloying elements is not controlled. In practice, structural steels of ordinary quality are most often used. They are used everywhere. They are used for the production of rolled metal. Designated by indicating the approximate carbon content of the alloy. The most common brands are shown in table. 1.

Table 1: Chemical composition and markings on the ends of rolled metal of structural steel of ordinary quality

steel grade	carbon,%	Limit sulfur content (no more), %. Determined by analysis results	Permissible phosphorus content (no more), %. Determined by analysis results	Color marking on the end of the rolled metal
St0	0,12±0,07	0,070±0,005	0,055±0,005	White
St1	0,09±0,03	0,045±0,005	0,055±0,005	White + yellow
St2	0,12±0,03	0,045±0,005	0,055±0,004	Yellow
St3	0,18±0,04	0,045±0,004	0,055±0,004	Red
St4	0,22±0,04	0,045±0,004	0,055±0,004	Red + green
St5	0,32±0,05	0,045±0,004	0,055±0,003	Green
St6	0,43±0,06	0,045±0,003	0,055±0,003	Blue
St7	0,56±0,06	0,045±0,003	0,055±0,003	Blue + white

Alloy steel

Alloying additives improve performance. Each element has a specific letter. It indicates what percentage of a particular substance is present in the composition of a complex alloy (Table 2).

Table 2: Alloying elements in the alloy composition

№	Marking of elements in steels	Chemical name	Chemical element designation	№	Marking of elements in steels	Chemical name	Chemical element designation
1	L	Beryllium	Be	14	D	Copper	Cu
2	R	Bor	B	15	Gl	Gallium	Ga
3	A	Nitrogen	N	16	E	Selenium	Se
4	Sh	Magnesium	Mg	17	C	Zirconium	Zr
5	YU	Aluminum	Al	18	B	Niobium	Nb
6	WITH	Silicon	Si	19	M	Molybdenum	Mo
7	P	Phosphorus	P	20	CD	Cadmium	Cd
8	T	Titanium	Ti	21	IN	Tungsten	W
9	F	Vanadium	V	22	And	Iridium	Ir
10	X	Chromium	Cr	23	AC	Lead	Pb
11	G	Manganese	Mn	24	In and	Bismuth	Bi
12	TO	Cobalt	Co	25	H	Rare earth metals
13	N	Nickel	Ni

In table 3 shows the most common steel grades.

Table 3: Steel grades and chemical composition

Brand	Carbon, C	Manganese, Mn	Silicon, Si, no more	Nickel, Ni, no more	Copper, Cu, no more	Chrome,Cr	Titan,Ti	Aluminium, Al	Molybdenum, Mo	Sera, S	Phosphorus, P
St1kp(ps)	0,060,12	0,250,5	0,04

Source: https://metmastanki.ru/marki-stali-rasshifrovka

How to determine steel grade

There are simply a huge number of different steel options, each grade is characterized by its own specific features. If the manufacturer has not carried out markings, then you can find out the characteristics of the metal only by independently conducting various tests. We'll talk about this in more detail later.

How to determine steel grade

How to identify stainless steel: methods and materials

Stainless steel is the name of a group of iron alloys that contain corrosion-resistant metals. Carbon, titanium, copper are used as additives, and the composition also includes from 12 to 25% chromium and nickel. Alloy steel alloys are not susceptible to corrosion and are resistant to moisture, aggressive environments, alkalis and acids.

Stainless steel is used to produce dishes, knives, elements of machine tools, cars and industrial equipment, especially in the chemical and oil industries. Such scrap is accepted at a high price, which depends on the composition. The most expensive alloys are those with a high nickel content (from 10%). To get maximum profit from scrap metal, it is important to know how to identify stainless steel?

Metals and alloys that are often confused

The silver alloy of iron and chromium is suitable for the production of kitchen utensils, medical instruments, bearings, cutting elements, etc. But these items are also made from the following materials:

• nickel-plated brass (a white copper alloy with a zinc content of more than 25%);
• cupronickel (silver-white metal made from an alloy of copper and nickel);
• white copper (an alloy containing at least 25% nickel).

Polished aluminum, nichrome, nickel silver and other alloys used for the production of cookware, knives, and jewelry can easily be confused with alloy steel. Despite their similar composition and high nickel content, they are easily distinguished at a scrap metal collection point and will not be accepted at the desired price. There are several ways to determine whether aluminum or stainless steel has fallen into your hands: chemical, mechanical, etc.

Analysis using a magnet

In the laboratories of large collection points, a spectrometer is installed - an optical device for spectroscopic research. It is equipped with an interferometer to evaluate the intensity of spectral lines and measure wavelengths. The received data is processed by a computer, giving an accurate conclusion about the composition of the alloy.

If you need to identify stainless steel at home, use improvised but relatively reliable means. One of them is a magnet: it is generally accepted that stainless steel is not magnetic. However, this diagnostic method is not accurate enough, because martensitic and ferritic alloys have magnetic properties.

Using a magnet, only austenitic and austenitic-ferritic alloys with a high content of chromium and nickel can be detected. They are used to produce dishes, plumbing and refrigeration equipment, containers for food liquids, etc. Contrary to popular belief, it is impossible to accurately determine stainless steel with a magnet, but you can roughly identify its type.

Defining food grade stainless steel

As stated above, a magnet helps to identify food grade stainless steel at home. Alloys with a low carbon content and a large amount of nickel in the composition do not react to contact with it. Stainless steel with a high carbon content (more than 0.9%) has magnetic properties and is prohibited for use in the food industry.

Also, to determine food grade stainless steel, various acids are used (citric, tartaric, acetic, etc.). Alloys for food applications contain more alloying additives, so their surface film is stronger and contains almost no iron.

For additional protection against corrosion, passivation is used - a method of treating the surface of a metal, as a result of which its activity is reduced and it does not enter into oxidative reactions.

Under the influence of these acids, stainless steel may become covered with a light patina, which indicates its non-food purpose.

Types and grades of non-magnetic steels

If the origin of the product is known, the reaction with a magnet can roughly determine the type of stainless steel. The following brands are not magnetic:

• AISI 409 (analogue 08X13) - containers for cargo transportation, parts for the exhaust system of a car, etc. are made from this ferritic steel. (plasticity and lack of magnetic properties are due to the extremely low C content - less than 0.03%);
• AISI 304 (analogous to 8-12X18H10) - household items are made from it, as well as utensils and equipment for the food and pharmaceutical industries;
• 12Х21НБТ (ЭИ8П) – austenitic-ferritic steel for use in medium-aggressive environments, from which containers and equipment for the chemical and pharmaceutical industries are produced.

Stainless steel grades AISI 402–420, which contain from 11 to 14% chromium and less than 0.07% carbon, are not magnetic.

Magnetic stainless steel

AISI 430 steel (analogous to 08X17, which contains 15% chromium) has magnetic properties. It is used to produce wire mesh, pipes for transporting petroleum products, and elements of gas and oil refining process plants. Steel grade AISI 630 contains up to 5% nickel and chromium, as well as a large number of additives: copper, titanium, molybdenum. It is used in instrument making and metallurgy.

Stainless steel can be identified even if it is magnetic. To do this, place a sample of the material in 2% vinegar or another aggressive medium for 1–2 days. Corrosion-resistant alloys will pass this test without visible changes, but metals that are susceptible to corrosion will darken.

Copper sulfate will also help determine magnetic stainless steel at home. First clean the metal surface with sandpaper, and then apply a few drops of a concentrated substance (rusting alloys are covered with a red film).

Spark test

Testing metal for spark color is a common method of sorting scrap metal, which is used even by specialists. The grade of stainless steel can be determined by the following factors:

• the number of sparks and flashes, which is directly proportional to the volume of carbon in the alloy;
• the color of the sparks, which indicates the composition of the metal (the lighter it is, the higher the likelihood that this is low-carbon steel);
• the presence of shiny white sparks, which indicates a high titanium content in the composition.

To carry out the test, an angle grinder (grinder) is required. Start grinding the surface of the steel and observe the reaction. The color, length and shape of the sparks will help you accurately determine metal or stainless steel.

"Yellow flow" or "white fork"

There are many types of sparks: “fork”, “twig”, “arrow”, etc. You learn to distinguish them with experience, but even an untrained person will be able to distinguish a dense and short stream of flashes from the long and rare sparks characteristic of stainless steel. The presence of dark red sparks coming out from under the grinding wheel indicates a high content of nickel, tungsten carbide and cobalt.

If a medium-density stream appears during the grinding process, and the sparks are straw-yellow at the base and white at the end, you have stainless steel. A long stream of sparks, reaching 1.5 meters, indicates the presence of nitrogen in the composition. In this case, it is not difficult to determine the grade of stainless steel: nitrogen alloys are quite rare and there are only a few of them (Nitrobe 77, Sandvik™ 14C28N, Böhler N680, etc.).

What does the price depend on?

Low-carbon, corrosion-resistant alloys are used to produce a wide variety of products: blades, profiled sheets, roofing materials, medical supplies. Scrap stainless steel can be collected when dismantling an old fence, dismantling an old refrigerator, throwing away unnecessary kitchen utensils, etc. In this case, potential income will depend on the following factors:

• type of steel (austenitic, ferritic, martensitic, etc.);
• steel grade (AISI 304, AISI 630, 12Х21НБТ);
• type of rolled metal (sheet, section, pipe);
• sheet thickness;
• compound;
• quality.

You can determine the stainless steel brand and composition in a laboratory setting by contacting a reliable collection point. We have the necessary equipment to analyze the composition, assess the quality and test the radiation activity of non-ferrous scrap. But you can pre-evaluate scrap metal at home.

How to evaluate quality?

The quality of stainless steel depends on various factors - from the amount of additives to the joining method. In places where welds are formed, the anti-corrosion properties of the metal deteriorate significantly, which over time leads to the appearance of rust and gradual destruction of the material.

Painted profiled sheets will have to be cleaned of the coating and sanded, damaging the protective layer on the surface. Accordingly, the metal will become less resistant to moisture, its quality will deteriorate, and therefore the price of such scrap will be lower. You can preliminary evaluate the properties of steel using a salt solution.

It should not leave stains on the surface of high-alloy steel. And water will leave yellowish stains on low-quality stainless steel.

The most expensive types of stainless steel

The cost is affected by the amount of nickel in the alloy: in the cheapest types its content does not exceed 5%. The most expensive are high-alloy alloys containing nickel from 12%. The expensive scrap includes plumbing fittings and rings, wire and various electrical connectors (connectors, adapters, etc.). Matte (a by-product of non-ferrous metallurgy) with a nickel content of over 35% is also highly valued, although it is classified as slag.

But the most common steel grade is A2, containing approximately 10% nickel and 18% chromium. It is usually used to make household items. To find out the exact price, visit our collection point: to evaluate scrap, specialists must inspect the metal, assess the degree of contamination, composition and properties.

Source: https://blog.blizkolom.ru/kak-opredelit-nerzhavejku

How to decipher steel grade

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: http://uraltm08.ru/stati/kak-rasshifrovat-marku-stali.html

How to determine the grade of steel: by chemical composition, by the color of the spark

There are simply a huge number of different steel options, each grade is characterized by its own specific features. If the manufacturer has not carried out markings, then you can find out the characteristics of the metal only by independently conducting various tests. We'll talk about this in more detail later.

How to determine steel grade

How to determine steel grade?

The creation of metal structures from steel requires the selection of material in accordance with the technical specifications and taking into account the characteristics of steel grades. Determining such characteristics is possible by deciphering the alphanumeric code on the metal marking. However, such a mark cannot always be seen on workpieces; in this case, the determination of the metal grade is carried out using a laboratory method, including using methods based on testing mechanical properties.

Basic methods for determining steel grades

When working with metal, methods for determining the quality of steel are still used today by analyzing its mechanical and physical characteristics. Such methods, unlike laboratory ones, make it possible to approximately determine the qualitative characteristics of the sample, but for work, in particular for welding metal, this is quite enough. Such methods for studying steel grades include:

• When it comes to the strength of metal, the chip removal method is used. Its essence is to remove metal shavings using a chisel. Chips that crumble and form into small strips are characteristic of high-carbon steels. Long strips of ductile chips characterize the metal as steel with high ductility.
• The quenching method is used to approximate the carbon content of the workpiece. Using a saw blade, cuts are made on the workpiece before and after hardening. If in both cases the metal is easily sawn with a blade, it contains a small amount of carbon. If it is difficult to make cuts after processing, it means that the carbon concentration has increased.
• Determining the hardness of a metal by extracting a sheaf of sparks allows you to approximately determine which class of steel the metal belongs to. To do this, surface treatment of the workpiece sample is done on an emery wheel. The shape of the sparks, color, and intensity of the sheaf of sparks determines the hardness of the metal and the carbon content.

Under ordinary home conditions, it is almost impossible to accurately determine the brand and composition of the metal; for this purpose, laboratory tests are carried out, during which a detailed chemical and physical analysis of the metal is performed. The listed methods make it possible to determine only the general characteristics of steel based on its carbon content; the exact characteristics are not determined during such studies.

At the same time, even such a rapid analysis makes it possible to select samples for the manufacture of knives, cutters or parts of machine mechanisms with increased strength and wear resistance.

Marking of steels and their properties

Much more information about the metal can be provided by the markings applied to the samples or the code indicated in the accompanying documents. In the countries of the former USSR, markings for metal for domestic use are indicated in accordance with national state standards developed on the basis of the steel grade of the former USSR. For foreign customers, markings are indicated in accordance with international standards.

For domestic samples, the steel designation is indicated in the first letter code with the signs “St” - steel. The first number after the letter designation indicates the amount of carbon contained in the metal, followed by the codes of alloying components and additives. Letter designations indicate the content of individual additives that significantly affect the quality of the metal, for example, chromium, copper or aluminum.

The description may also indicate separately the purpose of the steel:

• Structural;
• Instrumental;
• Mechanical engineering;
• High-speed;
• Low alloy;
• Wear-resistant;
• Magnetic;
• Stainless;
• Heat resistant.

More detailed information about the chemical and physical properties of such steels can be found in collections of characteristics of grade steels. The reference standards indicated in the reference book provide ideas about the properties of the metal and the possibilities of its application.

Source: https://1nerudnyi.ru/kak-opredelit-marku-stali-10/