JB/T 51117-1999
Internal Combustion Engines - Valve Seat - Product Quality Grading (Internal Use)
内燃机 气门座 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 检验方法 → 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 seats of reciprocating internal combustion engines with cylinder diameters less than or equal to 200 mm (hereinafter referred to as valve seats). This standard applies to the inspection and evaluation of the product quality of internal combustion engine valve seats.
本标准规定了气缸直径小于或等于200 mm 的往复式内燃机气门座（以下简称气门座）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座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 seat products. It helps ensure that valve seats meet qualified or first-class requirements in hardness, dimensions, surface quality, etc., thereby ensuring engine reliability and service life. The standard provides a basis for product quality control through unified inspection rules and sampling plans.
内燃机制造商和质检机构使用这个标准来对气门座产品进行质量分级和检验。它帮助确保气门座在硬度、尺寸、表面质量等方面达到合格或一等品要求，从而保证发动机的可靠性和使用寿命。该标准通过统一的检验规则和抽样方案，为产品质量控制提供了依据。
AI Summary AI generated
This standard applies to valve seats of reciprocating internal combustion engines with cylinder diameters ≤200 mm, specifying product quality grading indicators, inspection methods, and rules. Key technical indicators include hardness (qualified ≥32 HRC, first-class ≥34 HRC), hardness difference, chemical composition, metallographic structure, dimensional tolerances, surface roughness, geometric tolerances, surface quality, and service life (qualified 3000h, first-class 4000h). Inspection methods cover hardness, surface quality, metallography, chemical composition, roughness, dimensions, and geometric tolerances. Inspection rules adopt the sampling plan of GB/T 2828, with classification into A, B, and C nonconformities, and specify AQL values and evaluation procedures for qualified and first-class products.
本标准适用于气缸直径≤200mm的往复式内燃机气门座，规定了产品质量分等的指标、检验方法和规则。主要技术指标包括硬度（合格品≥32HRC，一等品≥34HRC）、硬度差、化学成分、金相组织、尺寸公差、表面粗糙度、形位公差、表面质量和使用寿命（合格品3000h，一等品4000h）。检验方法涉及硬度、表面质量、金相、化学成分、粗糙度、尺寸和形位公差等。检验规则采用GB/T 2828的抽样方案，按A、B、C三类不合格进行判定，并规定了合格品和一等品的AQL值及评定程序。
Key Sentences extracted from text
本标准规定了气缸直径小于或等于200 mm 的往复式内燃机气门座（以下简称气门座）产品质量指标、检验方法、检验规则。
合格品硬度大于或等于32 HRC，一等品硬度大于或等于34 HRC。
同一件气门座各点硬度差合格品应小于或等于5 个HRC 单位，一等品应小于或等于3 个HRC 单位。
密封锥面不得有裂纹、疏松、气孔和夹渣等缺陷。
合格品3 000h，一等品4 000 h。
This standard specifies the product quality indicators, inspection methods, and inspection rules for valve seats of reciprocating internal combustion engines with cylinder diameters less than or equal to 200 mm (hereinafter referred to as valve seats).
Qualified product hardness is greater than or equal to 32 HRC, first-class product hardness is greater than or equal to 34 HRC.
For the same valve seat, the hardness difference at various points for qualified products shall be less than or equal to 5 HRC units, and for first-class products less than or equal to 3 HRC units.
The sealing cone surface shall not have defects such as cracks, porosity, blowholes, and slag inclusions.
Qualified product service life is 3000 h, first-class product service life is 4000 h.
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.