Bearing Steel

Introduction to the Representation Method of Bearing Steel Grades in Various Countries in the World (marketing department of Shanghai HY Industry Co., Ltd)

1. According to the standard of ISO/DIS683/17-1976 “Heat Treatment, Alloy Steel and Free-cutting Steel”, Part 17 “Ball and Roller Bearing Steel” is applicable to five types

(1) Fully hardened bearing steel

(2) Carburized bearing steel

(3) Induction hardened bearing steel

(4) Stainless bearing steel

(5) High temperature bearing steel

2. Bearing steel grade

(1) Fully hardened bearing steel, there are 8 grades. The carbon content is about 1%, and the chromium content is between 0.90% and 2.05. Among them, the chemical composition of the grade 100Cr6 is basically the same as that of the Chinese GCr15 high carbon chromium bearing steel; the chemical composition of the grade 100CrMnSi4-4 is basically the same as that of the Chinese GCr15SiMn.

(2) Carburized bearing steel, its grades are 10, 11, 12, 13, 14, 15, and 16, with a carbon content of 0.13 to 0.23% and a nickel content of 0.40 to 3.75%. Among them, the steel grade 16 is 18NiCrMo14-6, with a carbon content of 0.15 to 0.20, a chromium content of 1.30 to 1.60%, and a nickel content of 3.25 to 3.75%. The chemical composition is basically the same as that of China’s G20Cr2Ni4 carburized steel.

(3) There are four grades of induction hardened bearing steel. The chemical composition of the grade 43CrMo4 with carbon content of 0.40-0.46%, chromium content of 0.90-1.20% and molybdenum content of 0.15-0.30% is basically the same as that of China’s 42CrMo, alloy structural steel.

Representation method of Chinese (GB) steel product grades

1. According to the GB221-2000 “Representation Method of Steel Product Grades”, the standard is applicable to bearing steel, alloy structural steel, stainless steel, heat-resistant steel, etc.

(1) The representation of product grades is generally represented by the combination of Chinese pinyin letters, chemical element symbols and Arabic numerals. The commonly used chemical element symbols are as follows: For example: carbon “C”, manganese “Mn”, chromium “Cr”, silicon ” Si”, nickel “Ni”, molybdenum “Mo”.

(2) “Ball” bearingsteel adopts Chinese characters and Chinese pinyin “roll” or “G”, and is preceded by the steel number.

2. Bearingsteel grades, bearingsteels are divided into four categories: high carbon chromium bearingsteel, carburized bearing steel, high carbon chromium stainless steel and high temperature bearing steel.

(1) High carbon chromium bearing steel (GB/T18254 “High carbon chromium bearing steel”) is marked with “G” at the head of the grade, but the carbon content is not indicated. The chromium content is measured in thousandths, and other alloying elements are The alloy content of alloy structural steel is expressed. For example, bearing steel with an average chromium content of 1.5% is designated as “GCr15”.

(2) Carburizing bearing steel (GB3203-82 “Technical Conditions for Carburizing Bearing Steel”), using the designation method of alloy structural steel, only the symbol “G” is added to the head of the designation, and the carbon content in the steel is the average carbon content. It is expressed in ten thousandths of the amount; the content of the main alloying elements in the steel is generally expressed in a few percent. When the average content is less than 1.5%, only the element (international chemical symbol) is indicated in the steel number, but the content is not indicated. When the average content is equal to or greater than 1.5%, 2.5%, 3.5%, etc., the content should be marked after the element, and 2, 3, 4, etc. can be written accordingly. Example: carburized steel with an average chromium content of 1.5% and an average nickel content of 3.5% should have a steel grade of “G20Cr2Ni4”, and high-quality carburized bearing steels should be marked with “A” at the end of the grade.

(3) Alloy structural steel for induction hardening (GB/T3077-1999 “Alloy Structural Steel”) steel grades are represented by Arabic numerals and alloying element symbols. Use two Arabic numerals to represent the average carbon content (in ten thousandths) and put it on the head of the brand. Expression method of alloying element content: when the average content is less than 1.5%, only the element is indicated in the grade, and the content is generally not indicated; when the average alloying element content is 1.5% to 2.49%, 2.50% to 3.49%, 3.5% to 4.49%… Write 2, 3, 4, etc. after the alloying elements accordingly. For example: the steel grade of alloy structural steel with carbon content of 0.38% to 0.45%, chromium content of 0.90% to 1.20%, and molybdenum content of 0.15% to 0.25% is 42CrMo.

Soviet Union (ГОСТ) steel product brand representation method

1. ГОСТ is the standard code of the Soviet Union’s national all-Soviet standard, the standard used in the production and manufacture of rolling bearings. (1) ГОСТ801-78 “Technical Conditions for Ball Bearing Steel” (2) ГОСТ800-78 “Technical Conditions for Bearing Steel Pipes” (3) ГОСТ21022-75 “Chromium Steel for Precision Bearings” (4) ГОСТ4727-83 “Technical Conditions for Bearing Steel Wires”

2. Bearing steel grades

(1) The beginning of the rolling bearing steel number is prefixed with the letter “Щ” to indicate: bearing.

(2) The alloy element chromium is represented by “X”, silicon is represented by “C”, and manganese is represented by “Г”.

(3) The representation method of steel number is basically the same as that of Chinese GB standard. The numbers 4, 5, and 12 in the grade indicate that the chromium content in the steel is 0.4%, 1.5%, and 2.0%, respectively. Example: Щ×15=GCr15Щ×15Сг= GCr15SiMn

(4) The “Щ” at the end of the steel number indicates electroslag remelting smelting. The “B” at the end indicates vacuum smelting production. “ЩД” at the end means electroslag remelting and then vacuum-arc remelting.

Representation method of steel grade for U.S. steel products

1. The national standard in the United States is the ASA standard formulated by the American Standards Association, but the grades of steel products mostly adopt the grade representation method of the standards of various American associations

(1) AISI-Steel Association Standard

(2) SAE-Society of Automotive Engineers Standard

( 3) ASTM-Material Testing Association Standards

(4) FS-Government Standards Because there are many standard systems used, the steel number representation methods of various types of steel are different. Not only does not adopt a unified standard system, but also often exists in the same type of steel. Several standard systems of steel number representation.

2. Rolling bearing steel

Rolling bearing steel generally adopts ASTM and SAE standard steel number system, and also adopts FS standard steel number system. (1) High carbon chromium bearing steel

  • Standard ASTMA 295-1994 “High Carbon Wear-Resistant Bearing Steel”

  • ANSI/ASTMA-295 “High Carbon Ball and Roller Bearing Steel”

  • ASTMA-485-1994 “High Hardenability Wear-Resistant Bearing Steel”

  • ANSI/ASTMA-535 “Quality Ball and Roller Bearing Steel”

  • ASTMA535-1992 “Special Quality Grade Ball and Roller Bearing Steel”

  • ASTMA866-1994 “Medium Carbon Wear-Resistant Bearing Steel”

The steel grade of high-carbon chromium bearing steel consists of five digits. The first digit is “5”, which indicates the chromium steel. The second digit indicates the level of chromium content. The last three digits indicate the average carbon content.

 

AISI

SAE

FS

Steel type

Average chromium

E50100

50100

FSE50100

Low chrome

0.50%

E51100

51100

FSE 51100

Medium chrome

1.00%

E52100

52100

FSE 52100

High chrome

1.45%

 

For example: 52100 has a carbon content of 0.95% to 1.10% and a chromium content of 1.30% to 1.60%. It is a high carbon chromium bearing steel, which is equivalent to Chinese GCr15 bearing steel.
(2) Carburized bearing steel
Carburized bearing steel belongs to alloy structural steel. Generally, AISI and SAE standard steel numbers are used to represent the steel numbers. The steel numbers are represented by four-digit numbers. numerical value.
The specific numbering system is: (Part of this excerpt)

SAE Steel mark representation method

2XXX

3XXX

4XXX

5XXX

8XXX

9XXX

Ni steel

Ni-Cr steel

Mo steel

Cr steel

Low NICRMO

NICRMO

 Meaning of the second number

 Represents the approximate value of nickel content as a percentage

 Represents the approximate value of nickel content as a percentage

 Represents the content of other alloying elements

 Represents the percentage of chromium content

 Denotes the contents of different nickel, chromium and molybdenum

 Which steel class it belongs to

for example:

23XX Ni3.5%

25XX Ni5.0%

31XX Ni1.25%、Cr0.65%

33XX Ni3.5%

Cr1.55%

40XX Mo% different

44XX Mo% different

45XX Mo% different

43XX NiCr% different

47XX NiCr% different 46XX NiMo% different 48XX NiMo% different

50XX Cr0.27-0.65%

51XX Cr0.80-1.05%

86XX

87XX

88XX

Average Ni0.55%、

Gr0.50%

Mo% different

92XX SiMnsteel

93XX Ni3.25%

Cr1.20%

Mo0.12%

94XX Ni0.45%

Gr0.4%

Mo0.12%

97XX Ni0.55%

Gr0.17%

Mo0.20%

For example; 4320 nickel content 1.65% ~ 2.00% is equivalent to Chinese G20CrNi2Mo carburized bearing steel (for railway freight car bearings) chromium content 0.40% ~ 0.60% molybdenum content 0.20% ~ 0.30% SAE 9310 nickel content 3% ~ 3.5% is equivalent to Chinese G10CrNi3Mo carburized bearing steel with a chromium content of 1.0% to 1.4% and a molybdenum content of 0.08% to 0.15%. 5. The British (BS) standard steel number representation method is generally the BS standard, and the BS steel number is mainly based on It is indicated by the purpose and cannot indicate the chemical composition of the tapped steel. The BS standard number is BS××, and ×× is the number of the number, which does not necessarily have a specific meaning. It doesn’t have to be a sequence number either. Therefore, the understanding of BS steel grades is mainly to consult the relevant parts of the standard or manual.

  • High carbon chromium bearing steel:It includes most of the high quality steel, mainly structural steel, according to the BS970 steel grade standard. The steel number is generally prefixed with “En” at the beginning, followed by the sequential number of Arabic numerals, indicating steel types for different purposes. Some steel numbers are also marked with one letter or two letters after the serial number. Example: En31 means 1% carbon chromium steel, which is equivalent to GCr15 bearing steel, and En18 means 1% chromium steel.

  • Carburized bearing steel:According to BS970 steel numbers, they are all prefixed with En at the beginning, followed by Arabic numerals, and some steel numbers are marked with letters after the sequence number. En325 is low Ni-Cr-Mo carburized steel, equivalent to Chinese G20CrNi2Mo carburized bearing steel (for railway freight car bearings) En 36C-3%Ni-Cr-Mo, equivalent to Chinese G10CrNi3Mo carburized bearing steel En 39A-1 /4% Ni-Cr carburized steel En 39B-4¼% Ni-Cr-MoX carburized steel, equivalent to Chinese G20Cr3Ni4 carburized bearing steel.

  • Alloy structural steel:En 19C is 1% Cr-Mo steel, which is equivalent to 42CrMo alloy structural steel in Chinese. En 43A is carbon steel, which is equivalent to 50Mo carbon structural steel in Chinese

Japan (JIS) standard steel number representation method

  • JIS is the code name of Japanese Industrial Standard. Steel numbers generally use two or more uppercase English letters. The first letter “S” represents the grade of steel, and the second letter represents the type of material, use or main chemical composition, etc. . Behind the English letters are Arabic numerals, most of which represent sequential numbers. The expression method of JIS steel number only shows the abbreviation of use and main components, but cannot specifically express the chemical composition of the steel. 1. The high carbon chromium bearing steel adopts the standard of JISG4805-1990 “High Carbon Chromium Bearing Steel”, the steel number is SUJX, and “X” is the serial number of the steel. There are 5 kinds of steel grades: SUJ1, SUJ2, SUJ3, SUJ4 and SUJ5. The average carbon content is 1%, the chromium content varies from 0.90% to 1.60%, and the other alloying elements Si and Mn are also different. Example: SUJ2 is equivalent to Chinese GCr15 bearing steel SUJ5 is equivalent to Chinese GCr15SiMn bearing steel 2, carburized bearing steel Carburized bearing steel is a structural steel, and the nickel-chromium-molybdenum alloy elements used are respectively represented by “N, C, M” letters. Namely: nickel-chromium steel ㅡSNCX, nickel-chromium molybdenum steel ㅡ SNCMX, where “X” is the serial number of the steel. For example: SNCM25 is equivalent to Chinese G20Cr2Ni4 SNCM23 is equivalent to Chinese G20CrNi2Mo (for railway freight car bearings) 3, alloy structural steel steel grade SCM4 is equivalent to Chinese 42CrMo alloy structural steel.

French (NF) standard steel number representation method

  • NF is the standard code for French standards, formulated by the French Standards Association. The standards related to steel products are stipulated in the NFA XXX standard, and the steel number representation method is recorded in the NDANO.30-009 standard. (FD represents the standard volume or annex)

In the steel classification system, bearing steel is classified into the alloy steelalloy steel for heat treatment” system.

When the total amount of alloy elements is less than 5%, it belongs to low alloy steel. 1. The high carbon chromium bearing steel adopts the first part of the three bearing steels stipulated in the NFA35-565-1994 “Quality of Metallurgical Products Bearing Steel” standard, “completely quenched and surface induction hardened steel”. The carbon content is represented by 100 times the number of C%, the main alloying elements are represented by capital letters, and the index of the element is specified. Chromium (Cr) steel number uses “C” letter, index is 4 silicon (Si) steel number uses “S” letter, index is 4 manganese (Mn) steel number uses “M” letter, index is 4 alloying elements The content of the main element is expressed by multiplying the percentage of the actual average content of the main element by the index of the element.

Example: GCr15 bearing steel, its average carbon content is 1%, then the 100 times value is 100 and its average chromium content is 1.5%, then the main element chromium content is 1.5 × chromium element index 4=6 France corresponds to the steel grade of GCr15 For 100C62, carburized bearing steel adopts NFA35-565-1994 “Quality of Metallurgical Products Bearing Steel” in the second part of “Carburized Steel”, the steel grade is in accordance with NFEN10027-1 “Steel Number Representation System – The first part is marked with the main symbol Representation designation” and A02-0053 “Steel designation system – Additional symbols for steel designation representation”. The carbon content is expressed in ten thousandths of the average carbon content. The main alloying elements are expressed in capital letters, and the index of the element is specified. The “N” letter is used in the nickel (Ni) steel number, the “D” letter is used in the index of 4 molybdenum (Mo) steel number, and the index is 10. The content of each alloy element is the actual average content percentage of the main element multiplied by the index. The index of the element is represented. For example: the average Ni content of G20Cr2Ni4 carburized bearing steel corresponding to France is 3.5%, then the average Ni content of 20NC14G20CrNi3 carburized bearing steel is 3.5%, then it is 20NC11

Representation method of German (DIN) standard steel number

  • DIN is the standard designation for German Industrial Standards. There are two ways to express the steel number of the DIN standard: the DIN17006 system and the DIN17007 system. According to the DIN17006 system (formulated by the German Iron and Steel Institute), various types of steel are classified as non-alloy steel, alloy steel, low alloy steel (the total alloy content in the steel is less than 5%), and high alloy steel (the total alloy content in the steel is more than 5%) Divided into four categories. The steel number is composed of three parts: (1) The main part of the strength or chemical composition of the steel. (2) The abbreviation letter indicating the smelting or original character of the crown in front of the main body. (3) The number representing the warranty coverage and the abbreviated letter of the treatment status appended to the main body.

  • High carbon chromium bearing steel High carbon chromium bearing steel is low alloy steel, and the current standard is “DIN17230 Technical Delivery Conditions for Rolling Bearing Steel”. The main body of the steel number is composed of a number representing the carbon content in ten thousandths, an alloying element symbol and a number representing the alloying element content value. The symbols of alloying elements are international chemical symbols and are arranged in order according to their content. Cr, Si, Ni, and Mn are composed by multiplying the percentage of the average content by the index 4, and Mn and AI are composed by multiplying the index by 10. For example: the carbon content of GCr15 is 0.95-1.05%, then the average carbon content is 1%, according to the DIN standard is 100/10,000, the average content of Cr is 1.5%, then it is 1.5×4=6, so the German GCr15 Code-named 100Cr62, carburized bearing steel German carburized bearing steel also adopts DIN17230 standard, the carbon content is expressed in ten thousandths of the average carbon content, and the content of each alloy element is the actual average content percentage of the main element multiplied by the element to represent the index. Example: The German corresponding G20Cr2Ni4 carburizing bearing steel with an average Ni content of 3.5% is 22NiCr14G20Cr2Ni3 carburized bearing steel with an average Ni content of 3.5% and 22NiCr11

Representation method of Czech (ČSN) standard steel number

ČSN is the standard code of Czech national standard. Czech steel number is usually marked with a number number, and its standard number is numbered with six digits. For six-digit numbers, the first digit “4” is for metallurgical materials. For structural steel, tool steel and stainless steel, the first digit “4” of the steel number is usually omitted, and the actual steel number of structural steel is mostly numbered with five digits. The combination of the first and second digits represents different steel types. For structural steel, the combined number is in the range of 12 to 16. The first “1” indicates steel, and the second “2 to 6” indicates the guaranteed chemical composition. High carbon chromium rolling bearing steel is “14”; carbon structural steel is “13”. The third digit represents the percentage of the total content of alloying elements in the steel; the fourth digit represents a fraction of a percent of the average carbon content in the steel. When the steel contains C>0.95%, it is represented by “0”. The fifth digit is to distinguish the steel grades with slightly different C content or alloying element content in the same steel series. The numbering method is to use the sequence number of 0, 1, 2… Then: GCr15 high carbon chromium bearing steel steel grade is 14100 GCr15SiMn is 14200 50Mn carbon structural steel is 13150

Representation method of Swedish

(SIS) standard steel number SIS is the standard code of the Swedish industrial standard. The steel product adopts the S1414XXXX standard of the Swedish Standards Committee, and its steel grade is represented by four digits, of which the first number is “1” It is carbon steel, “2” is alloy steel The second digit represents the alloying element in the steel, (usually refers to the one with the highest content) the element represented by the number is: 0=Si, 1=Mn, 2=low Cr, 3=High Cr, 5=Ni, 7=W, 9=A1 or V The third digit is the steel that belongs to the same steel group. The fourth digit indicates steel grades with slightly different composition ranges within the same steel group. 1. High carbon chromium bearing steel Sweden SKF company is the most authoritative company in the world bearing industry. Many standards related to the production, quality and inspection methods of bearings in the world are promulgated by the company, and the implementation standards are the most stringent. Therefore, the company’s high-carbon chromium bearing steel grade is directly represented by the SKF company followed by a number. For example: SKF3=GCr15, SKF24=GCr18Mo, SKF31=GCr9SiMn, SKF832=GCr15SiMn2, carburized steel 3, structural steel Sweden, this type is classified as quenched and tempered steel, and the steel number is represented by four digits as mentioned above. Example: The steel number of 42CrMo is SIS2244

Italian (UN1) Standard Steel Number

Representation Method UN1 is the Italian standard code, formulated by the Italian Standardization Association. The steel grade adopts the UN1 3344 standard, and its representation method is similar to the French NF standard. 1. High carbon chromium bearing steel The steel used for rolling bearings is the UNI3097 standard, which is an alloy structural steel. The steel number consists of a number + a capital letter representing the main alloying element (the capital letter of Cr is C) + a number II. The number I represents the ten thousandth of the carbon content in the steel. Number II ㅡ The content of alloying elements, which is expressed by multiplying the actual average content percentage of the main element by the letter C index of Cr 4, that is, the average Cr content is 1.5% multiplied by 4 to get 6 (1.5×4=6) When the main alloy in the steel The element content of Mn and Si is less than 1%, Ni is less than 0.50%, and Mo is less than 0.10%, so it is not necessary to mark it in the steel grade. For example: the UN1 code of GCr15 is 100C6, the UN1 code of GCr15SiMn is 25MC62, the alloy structural steel for induction hardening is according to the UN1 standard, and its representation method is similar to the French standard (this is omitted) Example: 50Mn code is UN152S842CrMo code is UN138CD4

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