1 Scope
This standard specifies the technical requirements and inspection method for hardening depth, hardness and microstructure of the needle bearing drawn cup and cage (hereinafter referred to as “bearing parts”) made from (08, 10, 15 and 20) high-quality carbon structural steels meeting the requirements of GB/T 699-1999 and 15CrMo and 20CrMo alloy structure steels meeting the requirements of GB/T 3077-1999, after carbonitriding heat-treatment.
This standard is applicable to the carbonitriding heat-treatment (effective hardening depth less than or equal to 0.30 mm) quality inspection of the bearing parts made from the above-mentioned steel types or the high-quality carbon structural steels and alloy structure steels with the equivalent performance. The carburizing heat-treatment quality inspection of the steel bearing parts with gross hardening depth less than or equal to 0.30 mm may be used by making reference.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards. For undated references, the latest edition of the normative document referred to applies.
GB/T 699-1999 Quality Carbon Structural Steels
GB/T 3077-1999 Alloy Structure Steels
GB/T 4340.1-2009 Metallic Materials-Vickers Hardness Test-Part 1: Test Method (ISO 6507-1:1997, MOD)
GB/T 9451-2005 Determination of Total or Effective Thickness of Thin Surface Hardened Layers of Steel Parts
JB/T 7361-2007 Rolling Bearings-Test Method for Hardness of Parts
Contents
Foreword I
1 Scope
2 Normative References
3 Terms and Definitions
4 Technical Requirements
4.1 Hardening Depth
4.2 Hardness
4.3 Microstructure
4.4 Miscellaneous
5 Inspection Methods
5.1 Inspection Sample
5.2 Determination of Hardening Depth
5.3 Hardness Test
5.4 Microstructure Inspection
Appendix A(Normative) Explanations on Grading Figure for Microstructure of Carbonitriding Layer
Table 1 Effective or Gross Hardening Depth
Table 2 Surface Hardness and Core Hardness
Table A.1 Explanations on Grading Figure for Microstructure of Carbonitriding Layer
