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进、排气门长期在高温燃气腐蚀和反复冲击的恶劣条件下工作。除了尺寸精度及形位公差要求较高外,对内在质量的要求也不断提高。如,过去对金相组织仅作回火索氏体的定性限制。如今,在NJ354-85标准里,对游离铁素体含量及奥氏体晶粒度都作了定量的规定（合金结构钢及马氏体耐热钢材料）。作为重要锻件,同样有镦锻纤维流的要求。翻阅国内外气门生产图纸和标准,几乎无一例外的写有“纵剖面宏观组织应符合外形的纤维方向,不得呈环圈或截断现象”的技术要求。然而这一技术要求一直没有认真考核。原因有三条:A·检查这一技术要求要做破坏性检查,手续比较麻烦。况且调整后的气门基本组织为正常回火索氏体。在一般光学显微镜下,从现场的整体上看,组织大体均匀一致,浑然一体,符合N J354-85气门金相组织的标准要求。看不出组织结构的细微变化,特别是没有和杆部进行
Into the exhaust valve long-term high temperature gas corrosion and repeated attacks under the harsh conditions. In addition to the higher dimensional tolerances and geometric tolerances, the inherent quality requirements are also continually increasing. For example, in the past, qualitative limitations on the microstructure of tempered sorbite were only made. Now, in the NJ354-85 standard, free ferrite content and austenite grain size are made quantitative provisions (alloy steel and martensitic heat-resistant steel material). As an important forgings, the same upsetting fiber flow requirements. Flip through the domestic and foreign valve production drawings and standards, almost without exception, wrote a “longitudinal section of the macro-organization should be consistent with the shape of the fiber direction, no ring or truncated phenomenon” technical requirements. However, this technical requirement has not been seriously examined. There are three reasons: A. Check the technical requirements to do destructive examination, the procedure is too much trouble. Moreover, the basic structure of the valve after adjustment for the normal tempered sorbite. Under the general light microscope, from the overall point of view, the organization is generally uniform and seamless, which meets the standard requirements of N J354-85 valve metallurgical organization. No subtle changes in the organizational structure can be seen, especially with the clubs