1 Scope
This Part of JB/T 6012 specifies the metallographic structure, inspection method and evaluation of intake and exhaust valves for internal combustion engine (hereinafter referred to as valve).
This part is applicable to the metallographic structure inspection evaluation for reciprocated piston internal combustion engine valves whose cylinder diameter is less than 200mm.
2 Normative References
Provisions of the following documents constitute some provisions of this part of JB/T 6012 through reference. For dated reference, subsequent amendments to (excluding correction to), or revisions of, any of these publications do not apply. However, the parties who enter into agreement according to these specifications are encouraged to research whether the latest editions of these labels are applied or not. For undated references, the latest editions of the normative documents are applicable to this part.
Contents
Foreword i
1 Scope
2 Normative References
2.1 Matrix Metallographic Structure
2.2 Nitrided Case
2.3 Clad Layer
2.4 Quench Hardening Layer at the Stem End
3 Inspection Method
3.1 Matrix Metallographic Inspection
3.2 Nitrided Case Inspection
3.3 Clad Layer Inspection
3.4 Hardening Layer Depth Inspection at the Stem End
4 Evaluation Standard of Metallographic Structure
4.1 Austenitic Grain Size
4.2 Free Ferrite
4.3 Nitrided Case Looseness and Nitride
4.4 Lamellar Educt
