JB/T 1255-2014Rolling bearings - Parts made of high-carbon chromium bearing steels - Specifications for heat treatment (English PDF)
滚动轴承 高碳铬轴承钢零件 热处理技术条件
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Issued by
MIIT
Level / Type
Industry · Recommended
Issue date
May 6, 2014
Implementation date
October 1, 2014
Scope
JB/T 1255-2014 is the English-translated version of 滚动轴承 高碳铬轴承钢零件 热处理技术条件.
JB/T 1255-2014 is the Chinese machinery industry standard for the heat treatment of rolling bearing rings and rolling elements made from the high-carbon chromium steels GCr15, GCr15SiMn, GCr15SiMo and GCr18Mo of GB/T 18254.
It fixes what the parts must show after spheroidizing annealing, after martensitic quenching and tempering, where hardness and the hardness spread within one part are tabulated, and after isothermal quenching to lower bainite.
Test methods are tied to the Rockwell, Brinell, Vickers and Leeb hardness standards and to JB/T 7361 and JB/T 7362. Normative annexes add the crushing load test for steel balls of 3 mm to 50.8 mm, hardness correction on curved surfaces and acid cleaning inspection.
It replaces JB/T 1255-2001, was issued on 6 May 2014 and has applied since 1 October 2014.
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Document preview — JB/T 1255-2014
National Standard of the People's Republic of China
- Replacing
- JB/T 1255-2001
Issued by: Ministry of Industry and Information Technology of the People's Republic of China
Contents
- Foreword3
- 1 Scope5
- 2 Normative References5
- 3 Technical Requirements6
- 4 Test Method9
- Appendix A (Informative) Effective Wall Thickness of Ring and Effective Diameter of Rollers17
- Appendix B (Normative) Test Specifications for Crushing Load of Steel Ball and Crushing Load Values19
- Appendix C (Informative) Decarburized Layer Depth of Bearing Parts after Quenching and Tempering22
- Appendix D (Informative) Allowable Deformation of Bearing Ring after Quenching and Tempering23
- Appendix E (Informative) Residual Austenite Content of Bearing Parts after Quenching and Tempering26
- Appendix F (Normative) Hardness Correction of Curved Surface27
- Appendix G (Normative) Acid Cleaning Inspection Specifications29
1 Scope
This standard specifies the technical requirements and test methods of the annealed, quenched and tempered rolling bearing ring and rolling element (hereinafter referred to as "bearing parts") made from GCr15, GCr15SiMn, GCr15SiMo and GCr18Mo steels which meet those specified in GB/T 18254-2002.
This standard is applicable to the heat treatment quality test of bearing parts during process and finished parts made from above-mentioned steels and also applicable to the heat treatment quality test of bearing parts made from other high-carbon chromium steels. The bearing parts with special requirements shall be in accordance with corresponding product drawings.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated references, only the dated editions apply. For undated references, the latest editions (including any amendments) apply.
GB/T 230.1 Metallic Materials - Rockwell Hardness Test - Part 1: Test method (scales A, B, C, D, E, F, G, H, K, N, T)
GB/T 231.1 Metallic Materials - Brinell Hardness Test - Part 1: Test Method
GB/T 1172 Conversion of Hardness and Strength for Ferrous Metal
GB/T 4340.1 Metallic Materials - Vickers Hardness - Part 1: Test Method
GB/T 6394 Metal - methods for Estimating the Average Grain Size
GB/T 17394 Metallic Materials - Leeb Hardness Test
GB/T 18254 High-carbon Chromium Bearing Steel
GB/T 24606 Rolling Bearings - Non-destructive Testing - Magnetic Particle Testing
JB/T 2974-2004 Rolling Bearings - Identification Code - Supplemental Regulations
JB/T 7361 Rolling Bearings - Test Method for Hardness of Parts
JB/T 7362 Rolling Bearings - Determination of Decarburized depth for Parts
3 Technical Requirements
3.2 Technical requirements of bearing parts Martensite after quenching and tempering
3.1 Technical requirements of bearing parts after spheroidizing annealing
The technical requirements of bearing parts after spheroidizing annealing shall be in accordance with those specified in Table 1.
3.2.1 Hardness
The hardness and hardness difference of the same bearing part after quenching and tempering of Martensite shall be respectively in accordance with those specified in Table 2 and Table 3.
3.3 Technical requirements of bearing parts Bainite after isothermal quenching
The isothermal quenching structure of bearing parts shall be composed of lower Bainite and residual carbide, a small quantity of acicular or massive Troostite and small quantity of residual austenite are allowed. The hardness and microscopic structure of bearing parts after isothermal quenching shall be in accordance with those specified in Table 5.
3.4 Other technical requirements
Other technical requirements of bearing parts shall be in accordance with those specified in Table 6.
4 Test Method
The test method shall be in accordance with those specified in Table 7.
Appendix A (Informative)
Effective Wall Thickness of Ring and Effective Diameter of Rollers See Figure A.1 for the requirements of effective wall thickness of ring and effective diameter of roller.
Appendix B (Normative) Test Specifications for Crushing Load of Steel Ball and Crushing Load Values
B.1 Scope
This Appendix specifies the test specifications for crushing load of ø3mm~ø50.8mm steel balls and their crushing load values.
B.2 Test specifications for crushing load of steel ball
B.2.1 Take three groups of heat treated steel balls (nine) from each batch for the crushing load test and the steel balls shall have the same dimension tolerance.
B.2.2 When the heat treated rerolled steel balls are subjected to the crushing test, the steel ball surface shall be free from grinding wheel defects, stain, bump or hard spots, etc.
B.2.9 The tester will vibrate greatly with pointer bounced and reading inaccurate when the steel balls crush; the attention shall be paid to the load reading when the steel balls are about to crush.
B.2.10 The crushing mould is so designed to suit the steel ball size, at an angle of 90°; the mould may be made of tool carbon steel or bearing steel and has 60HRC~65HRC hardness after quenching and tempering.
Appendix C (Informative)
Decarburized Layer Depth of Bearing Parts after Quenching and Tempering See Table C.1 for decarburized layer depth of bearing parts after quenching and tempering. INDUSTRY STANDARD OF THE PEOPLE'S REPUBLIC OF CHINA
ICS 21.100.20 J 11 Record Number.
Replacing JB/T 1255-2001 Rolling Bearings - Parts Made from High-carbon Chromium Bearing Steels - Specifications for Heat Treatment Issued on. MAY 6, 2014 Implemented on. OCTOBER 1, 2014 Issued by. Ministry of Industry and Information Technology of the People's Republic of China […]
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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 29 pages — is available in the English PDF.
Referenced standards
Normative references
- GB/T 230.1Metallic materials - Rockwell hardness test - Part 1: Test method
- GB/T 231.1Metallic materials - Brinell hardness test - Part 1: Test method
- GB/T 1172Conversion of hardness and strength for ferrous metal
- GB/T 4340.1Metallic materials - Vickers hardness test - Part 1: Test method
- GB/T 6394Determination of estimating the average grain size of metal
- GB/T 18254High-carbon chromium bearing steel
GB/T 17394
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- FZ/T 92013-2017SL series top roller bearings
- FZ/T 92024-2017LZ series bottom roller bearings
- GB/T 307.3-2017Rolling bearings - General technical regulations
- JB/T 10336-2017Rolling bearings and parts - Supplementary specifications
Similar standards
Editions of JB/T 1255
| Edition | Title | Revision | Status |
|---|---|---|---|
| JB/T 1255-2014 | Rolling bearings - Parts made of high-carbon chromium bearing steels - Specifications for heat treatment | current edition | Current |
| JB/T 1255-2001 | Rolling bearings - Parts made of high-carbon chromium bearing steels - Specifications for heat treatment | previous edition | Superseded |
This page sells the current edition, JB/T 1255-2014. Earlier editions are listed for reference only.
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Related Standards
GB/T 1172-1999 — Conversion of hardness and strength for ferrous metal
GB/T 17394.1-2014 — Metallic materials - Leeb hardness test - Part 1: Test method
GB/T 17394.1-2025 — Metallic materials - Leeb hardness test - Part 1: Test method
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