JB/T 51119-1999
Internal combustion engines - Valve tappets - Product quality grading (Internal use)
内燃机 气门挺柱 产品质量分等（内部使用）
Catalogue
前言 → 1 范围 → 2 引用标准 → 3 质量指标 → 4 检测方法 → 5 检验规则 Foreword → 1 Scope → 2 Normative References → 3 Quality Indicators → 4 Inspection Methods → 5 Inspection Rules
Scope
This standard specifies the product quality indicators, inspection methods, and inspection rules for valve tappets used in reciprocating internal combustion engines with cylinder diameter less than or equal to 200 mm. This standard applies to the inspection and evaluation of the quality of valve tappet products for internal combustion engines.
本标准规定了气缸直径小于或等于200 mm 的往复式内燃机用气门挺柱产品质量指标，检验方法，检验规则。本标准适用于内燃机气门挺柱产品质量的检验和评定。
Normative References
Keywords
Application Summary AI generated
Manufacturers of internal combustion engines and quality inspection agencies use this standard to grade and inspect valve tappet products. It helps determine whether products meet qualified, first-grade, or premium quality levels, ensuring reliability and consistency of this critical engine component. By providing unified quality indicators and sampling plans, the standard enhances quality control across the industry.
内燃机制造商和质检机构使用本标准来对气门挺柱产品进行质量分级和检验。它帮助确定产品是否达到合格品、一等品或优等品等级，确保发动机关键部件的可靠性和一致性。该标准通过统一的质量指标和抽样方案，提升了行业内的质量控制水平。
AI Summary AI generated
This standard applies to valve tappets for reciprocating internal combustion engines with cylinder diameters ≤200 mm. It defines three quality grades (qualified, first-grade, premium) and specifies requirements for materials, heat treatment, hardness, microstructure, dimensional tolerances, surface roughness, and geometric tolerances. Detailed inspection methods include magnetic particle testing, hardness testing, and metallographic analysis. Sampling and inspection rules follow GB/T 2828. The standard aims to unify quality assessment of valve tappets, ensuring reliability and interchangeability in engine applications.
本标准适用于气缸直径≤200mm的往复式内燃机气门挺柱，规定了产品质量分等的三项等级（合格品、一等品、优等品），涵盖材料、热处理、硬度、金相组织、尺寸公差、表面粗糙度、形位公差等质量指标，并详细描述了检测方法（如磁粉探伤、硬度测试、金相分析）和基于GB/T 2828的抽样检验规则。标准旨在统一内燃机气门挺柱的质量评定，确保产品可靠性和互换性。
Key Sentences extracted from text
本标准规定了气缸直径小于或等于200 mm 的往复式内燃机用气门挺柱产品质量指标，检验方法，检验规则。
气门挺柱按其不同质量指标定为合格品、一等品和优等品三个等级。
气门挺柱可采用20、45、15Cr、20Cr、20MnB、45Cr、50Mn2 钢制造，也允许采用物理、力学性能不低于上述钢的其它合金结构钢制造。
渗碳钢渗碳或碳氮共渗淬火后表层应为细针状马氏体，不允许有连续网状渗碳体存在，心部应为低碳马氏体和铁素体。
气门挺柱表面不允许有裂纹、锈蚀、疏松等缺陷。
This standard specifies the product quality indicators, inspection methods, and inspection rules for valve tappets used in reciprocating internal combustion engines with cylinder diameter less than or equal to 200 mm.
Valve tappets are classified into three grades: qualified product, first-grade product, and premium product according to their different quality indicators.
Valve tappets may be manufactured from 20, 45, 15Cr, 20Cr, 20MnB, 45Cr, 50Mn2 steel, and also from other alloy structural steels with physical and mechanical properties not lower than those of the above steels.
After carburizing or carbonitriding and quenching, the surface layer of carburizing steel shall be fine acicular martensite, with no continuous network cementite allowed, and the core shall be low-carbon martensite and ferrite.
The surface of valve tappets shall not have defects such as cracks, rust, or porosity.
Standard Timeline
Changes from replaced version:
- 对原标准作了编辑性修改，主要技术内容没有变化
- Editorial modifications were made to the original standard, with no changes to the main technical content.