Standard No.:	JB/T 1255-2014
English Name:	Rolling Bearings - Parts Made from High-carbon Chromium Bearing Steels-Specifications for Heat Treatment
Chinese Name:	滚动轴承 高碳铬轴承钢零件 热处理技术条件
Professional Classification:	JB    Professional Standard - Machinery
Issued by:	MIIT
Issued on:	2014-05-06
Implemented on:	2014-10-1
Status:	valid
Superseding:	JB/T 1255-2001 Specification for heat-treatment of rolling bearing parts made from high carbon chromium steel
Language:	English
File Format:	PDF
Word Count:	6000 words
Price(USD):	80.0
Delivery:	via email in 1 business day

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 Repuirements 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 Technical requirements of bearing parts martensite after quenching and tempering 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. Table 1 Technical Requirements after Spheroidizing Annealing

Foreword I 1 Scope 2 Normative References 3 Technical Repuirements 4 Test Method Appendix A (Informative) Effective Wall Thickness of Ring and Effective Diameter of Rollers Appendix B (Normative) Test Specifications for Crushing Load of Steel Ball and Crushing Load Values Appendix C (Informative) Decarburized Layer Depth of Bearing Parts after Quenching and Tempering Appendix D (Informative) Allowable Deformation of Bearing Ring after Quenching and Tempering Appendix E (Informative) Residual Austenite Content of Bearing Parts after Quenching and Tempering Appendix F (Normative) Hardness Correction of Curved Surface Appendix G (Normative) Acid Cleaning Inspection Specifications