This standard specifies the principles, contents, requirements and marking methods for the importance classification of quality characteristics of mechanical industrial products. This standard applies to the importance classification of mechanical industrial products. JB/T 5058-1991 Guidelines for the importance classification of quality characteristics of mechanical industrial products JB/T5058-1991 Standard download decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
JB/T5058—91
Guidelines for the Grading of Importance of Quality Characteristics of Machinery Industry Products
Issued on May 17, 1991
Issued by the Ministry of Machinery and Electronics Industry of the People's Republic of China
Implementation on July 1, 1992
Mechanical Industry Standard of the People's Republic of China
Guidelines for the Grading of Importance of Quality Characteristics of Machinery Industry Products
1 Subject Content and Applicable Examples
JB/T5058—91
This standard specifies the principles, contents, requirements and marking methods for the grading of importance of quality characteristics of machinery industry products (hereinafter referred to as importance grading).
This standard applies to the importance classification of mechanical industrial products. 2 Reference standards
GB.7635 National Classification and Code of Industrial and Agricultural Products (Commodities: Materials) 3 Terminology
3.1 Product Quality Characteristics
Product quality characteristics are determined by the specifications, performance and structure of the product and affect the applicability of the product. They are technical requirements and information that the design passes on to the process, manufacturing and inspection. It includes dimensions, tolerances and fits, functions, life, interchangeability, environmental pollution, personal safety and the implementation of relevant government regulations and standards.
3.2 Importance of product quality characteristics
The degree of importance that affects the applicability of the product. www.bzxz.net
4 General Principles
4.1 Formulate general rules for importance classification based on the sub-category products specified in GB7635. If the sub-category products are quite different from each other, the general rules for importance classification can also be formulated uniformly according to similar product series. Major products can also be classified separately. 4.2 During the design phase of new products, the design department shall classify the importance of the product, and further revise and complete the design through trial production of new products.
4.3 Importance Classification. The level symbols specified by the technology can be directly marked on the product drawings and design documents, or the importance classification documents of the whole machine and its components can be compiled separately.
5. Classification principles and importance levels
5.1 Importance classification is based on the impact on the product applicability requirements and the degree of economic loss. 5.2 The importance levels are divided into key characteristics, important characteristics and general characteristics. 5.2.1 Key characteristics
If a failure occurs, personal safety accidents will occur, the main functions of the product will be lost, the product performance will be seriously affected and the product life will be reduced, and the pollution to the environment will violate regulations, and the characteristics that will inevitably cause complaints from the user unit. 5.2.2 Important characteristics
If a failure occurs, it will affect the product performance and life, and the user unit may file a complaint. Approved by the Ministry of Machinery and Electronics Industry on May 17, 1991. Implemented on July 1, 1992
5.2.3 General characteristics
JB/T5058--91
Characteristics that will have little impact on the performance and life of the product and will not cause complaints from the user unit if a failure occurs. Importance classification content
Importance classification content generally includes:
Safety and environmental protection requirements;
Performance and structural use requirements;
Reliability, service life and interchangeability requirements: Material properties and processing regulations;
Welding and casting and forging regulations;
Dimensions, tolerances and fits, shape and position tolerances and surface roughness requirements; Shape and appearance requirements;
Cleanliness requirements:
Coating, packaging, protection and storage and transportation requirements. 7.1
For the symbols and marking methods of importance classification levels marked on product drawings and design documents, please refer to Appendix A (Supplement). 7.2 When a separate importance classification document is prepared, its table format and content are shown in Appendix B (Supplement). 2
A.1 Special number for level
Importance classification level symbols are shown in Table A1,
Characteristic level
Key characteristics
Important characteristics
General characteristics"
Note: 1)
Symbols can be specified when necessary,
General characteristics can be left unmarked,
Marking method
JB/T5058—91
Appendix A
Importance classification level symbols and marking method (supplement)
Grading symbols\
Generally, they should be marked on the right side of the characteristics, as shown in the following examples. Example 1150m6 ()
Example 2[]
Example 3 Service strength ≥200N/mm2[B]
Example 4 Contact area not less than 80 %[A]
Example 5$60+*
Example 6100±0.03[A]
Importance grading attenuation
3B/T5058—91
Appendix B
Importance grading table form and content
(Supplement)
The form and content of the importance grading table are shown in Table B1. Table
B2 Grading level
Code
Characteristic content
Grading level can be marked with “√\” in the corresponding level column, additional explanation:
This standard is proposed and managed by the Machinery Standardization Research Institute of the Ministry of Machinery and Electronics Industry. This standard is drafted by the Science and Technology Information Research Institute of Shanghai Mechanical and Electrical Industry Administration and the Machinery Standardization Research Institute of the Ministry of Machinery and Electronics Industry. The main drafters of this standard are Tang Fengzhu, Fang Jie, Xia Changkun, Zhang Shengming, Shen Longkun, Hu Baode, Lu Jingui and Ouyang Zhou.
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