This standard specifies the technical requirements, hardening layer depth, hardness measurement, and carbonitriding layer microstructure inspection procedures for rolling bearing parts made of carbon structural steels such as 08, 10, 15, 20 and alloy structural steels such as 15CrMo, 20CrMo after carbonitriding heat treatment. JB/T 7363-2002 Technical conditions for carbonitriding heat treatment of rolling bearing parts JB/T7363-2002 Standard download decompression password: www.bzxz.net

ICS21.100.20
Mechanical Industry Standard of the People's Republic of China
JB/T7363--2002
Replaces JB/T7363--1994
Specifications for carbonitriding heat treatment of rolling bearing parts2002-07-16 Issued
2002-12-01 Implementation
The State Economic and Trade Commission of the People's Republic of China Issued Foreword
Normative references
Terms and definitionsbzxZ.net
Technical requirements,
Deepth of hardened layer
4.3 Microstructure,
5 Measurement, inspection and evaluation methods
5.1 Test specimen.
Measurement of hardened layer depth
Hardness measurement
5.4 Microstructure inspection of carbonitriding layer
Appendix A (Informative Appendix) Foreign carbon cable structural steel grades Appendix B (Normative Appendix) Total hardened layer depth of carbonitriding Figure 1 Microstructure of carbonitriding layer
Table 1 Surface hardness and core hardness after direct quenching and tempering of carbonitriding Table A.1 Foreign carbon structural steel grades||t t||Table B.1 Total hardened layer depth of carbonitriding
JB/T7363--2002
This standard replaces JB/T7363-1994 "Technical Conditions for Carbonitriding Heat Treatment of Rolling Bearing Parts". Compared with JB/T7363-1994, the main changes in this standard are as follows: Added the terms and definitions of total hardened layer depth and effective hardened layer depth (see Chapter 3); - Added the provisions of total hardened layer depth of carbonitriding (see Appendix B); JB/T7363-2002
Modified and supplemented the provisions of surface hardness and core hardness of direct quenching and tempering of carbonitriding (3.2 of the 1994 edition, 4.2 of this edition);
The hardened layer depth of the cage was changed to total hardened layer depth (3.1 of the 1994 edition, 4.1 of this edition). Appendix A of this standard is an informative appendix, and Appendix B is a normative appendix. This standard is proposed by China Machinery Industry Federation. This standard is under the jurisdiction of the National Technical Committee for Standardization of Rolling Bearings (CSBTS/TC98). This standard was drafted by Luoyang Bearing Research Institute, and Suzhou Jincheng Bearing Co., Ltd., Suzhou Xinhao Bearing Co., Ltd., Wujin Nanfang Needle Roller Bearing Factory, Suzhou Dongwu Needle Roller Bearing Factory, and Wuxi Tiangong Bearing Factory participated in the drafting. The main drafters of this standard are: Lei Jianzhong, Xu Zhongfu, Jiang Kanglie, Wu Zhenliang, Yan Hanming, Yang Qiaoling, and Liu Jianliang. This standard was first issued in 1994.
1 Scope
Technical conditions for carbonitriding heat treatment of rolling bearing parts JB/T7363--2002
This standard specifies the technical requirements, hardened layer depth, hardness measurement, and carbonitriding layer microstructure inspection procedures for rolling bearing parts made of carbon structural steels such as 08, 10, 15, 20 (foreign grades can be found in Appendix A) and alloy structural steels such as 15CrMo, 20CrMo after carbonitriding heat treatment.
This standard is applicable to the quality inspection of carbonitriding heat treatment (effective hardened layer depth is less than or equal to 0.30mm) of the above-mentioned carbon structural steels and alloy structural steels and low-carbon steel cages and needle roller bearing stamping outer rings (thin-walled stretched outer rings) that meet the requirements of this standard. The quality inspection of carburizing heat treatment of steel cages and needle roller bearing stamping outer rings (thin-walled stretched outer rings) with a total hardened layer depth of less than or equal to 0.30mm can also be referred to.
2 Normative references
The clauses in the following documents become the clauses of this standard through reference in this standard. For all the referenced documents with dates, all the subsequent amendments (excluding errata) or revisions are not applicable to this standard. However, the parties who reach an agreement based on this standard are encouraged to study whether the latest versions of these documents can be used. For all the referenced documents without dates, the latest versions are applicable to this standard. GB/T4340.1-1999 Metal Vickers hardness test Part 1: Test method (eqvISO6507-1:1997) 3 Terms and definitions
The following terms and definitions apply to this standard. 3.1
Gross hardening depth gross hardening depth is the distance measured vertically from the surface of the part to the hardened layer with no obvious change in microhardness or microstructure with the base metal.
Effective hardening depth effective hardening depth is the distance measured vertically from the surface of the part to a certain microstructure boundary or a specified microhardness hardened layer. 4 Technical requirements
4.1 Depth of hardened layer
4.1.1 The depth of hardened layer of cage and stamped outer ring shall comply with the provisions of product drawings. If the user has requirements for the total depth of hardened layer, it can be in accordance with the provisions of Appendix B Total depth of hardened layer Table B.1. 4.1.2 The effective depth of hardened layer shall be measured from the surface hardness to 550HV. If there are special requirements, it can be determined by negotiation between the user and the manufacturer.
4.1.3 The depth of hardened layer of cage shall be based on the total depth of hardened layer. 4.1.4 The depth of hardened layer of stamped outer ring shall be based on the effective depth of hardened layer. 4.2 Hardness
The surface hardness and core hardness after carbonitriding direct quenching and tempering shall comply with the provisions of Table 1. 4.3 Microstructure
The microstructure of carbonitriding layer of rolling bearing parts shall be nitrogen-containing martensite, retained austenite and carbonitride. Figure 1a), b) are qualified, and the black structure of level 1 and level 2 shown in Figure 1c), d) is not allowed to exist. JB/T7363—2002
Table 1 Surface hardness and core hardness after carbonitriding direct quenching and tempering Hardness HV
Product type
Cage
Carbon structural steel
Alloy structural steel
Carbon structural steel
Stamped outer ring
Alloy structural steel
Surface hardness (minimum)
Note: If the user has no requirements for the core hardness, the manufacturer may not test its core hardness. 5 Measurement, inspection and evaluation methods
5.1 Sample
Surface hardness
380~650
420~620
664~856
664~856
Core hardness
140~380
270~350
140~450
270~450
Take the window lintel of the cage, cut a thin-walled tensile outer ring along the axial direction (either cross section or longitudinal section), and conduct metallographic inspection and microhardness measurement. The sample preparation should be prepared according to the requirements of surface metallographic analysis, and grinding and polishing should ensure that the sample edge has no chamfer or curling. For this reason, the sample can be protected by inlay or special fixtures. If necessary, the edge of the sample to be tested can be protected by copper sheet or electroplated metal. 5.2 Measurement of hardened layer depth
The measurement of hardened layer depth can be carried out by microhardness method and microstructure method. In case of dispute, microhardness method shall prevail. 5.3 Hardness measurement
5.3.1 Measurement method
Surface hardness and core hardness shall be measured in accordance with the provisions of GB/T4340.1-1999. 5.3.2 Measurement location
5.3.2.1 Surface hardness measurement location
The surface hardness of the cage shall be based on the measured value of the cage beam surface. The surface hardness of the thin-walled tensile outer ring can be measured directly on the end face if the end face is flat, and can be measured according to the method specified in GB/T4340.1-1999 if the end face is uneven. In case of doubt, the microhardness value of the stamped outer ring at 0.03mm away from the working surface shall be the surface hardness value. 5.3.2.2 Core hardness measurement position
The core hardness of the cage shall be measured at half of the cage cross section. The core hardness of the thin-walled tensile outer ring shall be measured at half of the sampling section.
5.4 Microstructure inspection of carbonitriding layer
The microstructure of the carbonitriding layer shall be inspected under a microscope with a magnification of 100 to 400 times. In case of doubt, 400 times shall prevail. The etchant can be 2%~4% nitric acid alcohol solution.
a) 400×
c) 1st grade 400X
Carbon-ammonia co-diffusion layer microstructure diagram
b) 400x
d) 2nd grade 400×
JB/T7363—2002
JB/T7363—2002
Appendix A
(Informative Appendix)
Foreign carbon structural steel grades
Table A.1 gives the foreign carbon cable structural steel grades. Table A.1
Foreign carbon structural steel grades
Appendix B
(Normative Appendix)
Total depth of carbonitriding hardened layer
The total depth of carbonitriding hardened layer is given in Table B.1. Total depth of carbonitriding hardened layer
Product type
Cage
Stamped outer ring
Minimum wall thickness
Total depth of hardened layer
Carbon structural steel
0.02~0.07
0.02~0.15
0.02~0.15
0.10~0.18
0.15~0.25
0.18~0.30
Unit: mm
Alloy structural steel
0.05~0.12
0.07~0.15
0.08~0.20
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