JB/T 9730-2011 in English

1 Scope

This standard specifies the examination of heat-treated metallographic structure of diesel injection nozzle, plunger for injection pump or high pressure supply pump and delivery valve (the effective thickness of parts is less than or equal to 12mm) for injection pump or high pressure supply pump.
This standard is applicable to the metallographic examination of GCr15 steel precision coupled parts; the metallographic examination of carburization and heat treatment of alloy structure steel needle valve body; and the metallographic examination of W6Mo5Cr4V2 and W18Cr4V steel needle valve.

2 Normative References

The following documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition (including any amendment) applies.
GB/T 3077 Alloy Structure Steels
GB/T 5264 Plunger of Diesel Fuel Injection Pump - Specifications
GB/T 5771 Delivery Valve of Diesel Fuel Injection Pump - Specifications
GB/T 5772 Injector Nozzle of Diesel - Specifications
GB/T 18254 High-carbon Chromium Bearing Steel
YB/T 5302 Steel Wire for High-speed Tool

3 Metallographic Examination of GCr15 Steel Precision Coupled Parts

3.1 Technical Requirements

Foreword i
1 Scope
2 Normative References
3 Metallographic Examination of GCr15 Steel Precision Coupled Parts
3.1 Technical Requirements
3.2 Examination Method
3.3 Grading Standard of Metallographic Microstructure
4 Metallographic Examination of Carburization and Heat Treatment of Alloy Structure Steel Needle Valve Body
4.1 Technical Requirements
4.2 Examination Method
4.3 Grading Standard of Metallographic Microstructure
5 Metallographic Examination of W6Mo5Cr4V2 and W18Cr4V Steel Needle Valve
5.1 Technical Requirements
5.2 Examination Method
5.3 Grading Standard of Grain Size and Superheat Degree
Appendix A (Normative) Measurement Method for Effective Hardening Depth of Carburization or Carbonitriding of Needle Valve Body after Quench Tempering
A.1 Application Scope
A.2 Load and Multiple
A.3 Requirement on Sample
A.4 Hardness Determination
A.5 Calculation of Effective Hardening Depth
A.6 Measurement Result Treatment
Appendix B (Informative) Corrected Value of Sample’s Grade C Rockwell Hardness