This standard specifies the technical requirements, inspection methods and acceptance rules for quenching and tempering of metal cutting machine tool parts. This standard is applicable to steel parts with surface hardness equal to or greater than 35HRC that are subjected to through-heat quenching and tempering in a heating furnace. JB/T 8491.2-1996 Technical conditions for heat treatment of machine tool parts Quenching and tempering JB/T8491.2-1996 Standard download decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
JB/T8491.2-1996
Technical Conditions for Heat Treatment of Machine Tool Parts
Quenching and Tempering
Issued on November 7, 1996
Ministry of Machinery Industry of the People's Republic of my country
Implementation on January 1, 1997
.TB/T 8491.2-1996
This standard is formulated based on the comprehensive production experience of many years in the heat treatment of parts in China and with reference to relevant foreign technical data.
From the date of implementation, this standard replaces JB/T54315---94 Machine Tool Parts Quenching and Tempering Standard proposed by the National Metalworking Machine Tool Standardization Technical Committee and is under the jurisdiction of the Beijing Machine Tool Research Institute of the Ministry of Machinery Industry. The drafting unit of this standard is: Beijing Machine Tool Research Institute of the Ministry of Machinery Industry. This standard was first issued in 1994. General technical conditions and regulations. Machinery industry standard of the People's Republic of China. Technical conditions for heat treatment of machine tool parts. Quenching and tempering. JE/T 8491.2-1996. Replaces JB/T5421594. This standard stipulates the technical requirements, inspection methods and acceptance rules for quenching and tempering of machine tool parts (hereinafter referred to as guide parts). This standard is applicable to parts with a hardness equal to or greater than 35HRC after quenching and tempering in a heating furnace. 2. Reference standards. The provisions contained in the following standards constitute the provisions of this standard through the use of the following standards. When this standard is published, the total versions shown are valid. All standards are subject to revision, and the parties using this standard are encouraged to discuss the possibility of using the new version of the following standards. GB 22493
GB 230--91
Determination of decarburization depth of steel
Test method for metallurgical structure
GB/13298-91
Metallic structure inspection method
ZBJ36UU3-87
ZBJ3601600
JB1255-9:
3 Appearance quality
Tool treatment metal inspection
Medium carbon and medium carbon alloy martensitic grade commercial cross-chromium auxiliary steel rolling parts heat treatment technical conditions 3.1 The surface of the parts should be clean, and cracks, damage, pitting, rust and bumps are not allowed. The surface of the parts treated in the absence of hydrogen should be free of oxidation color. 3.2 Check the appearance with naked eyes or low-profile inspection. If necessary, the crack effect can be checked by dropping sand or probing. 4 Surface hardness
4.1 The surface hardness of the parts shall comply with the requirements of the drawings and process documents. The surface hardness deviation is generally HRC. 4.2 The hardness test shall be carried out on the representative working surface of the parts according to the provisions of GB230. When the specified method is not used, other hardness test methods may be used.
5 Size of the hard zone
The size deviation of the hard zone of the local component shall comply with the provisions of Table 1. If there are special requirements for the size of the hard zone, it shall be implemented according to the process documents.
Approved by the Ministry of Machinery Industry on November 7, 1996
Applied on January 1, 1997
Parts should be light or effective
2 30-60
6 Microstructure
JB/T8491.2—1996
Zi Shi Di Long Seat
Required Area Size·A Drop
1/2 of the hard zone length
1 yuan of the running zone length
1/2 of the deep processing zone lengthwwW.bzxz.Net
6.1 Carbon structure, medium recovery structure pliers! The microstructure of the parts should be evaluated according to 7P36015, martensite 1--5 qualified spring steel parts, martensite 1~4 qualified. 6.2 The microstructure of carbon tool and alloy tool parts after annealing and curing shall be evaluated according to the tenth to thirteenth level drawings of JR 36003, and the 1-3.5 level is qualified. 6.3 The microstructure of bearing parts after annealing and curing shall be evaluated according to the second level of JR1255, and the main parts shall be qualified at levels 1-3, and the non-main parts shall be qualified at levels 1-7. 6.4 The microstructure of high-speed steel parts after annealing shall be evaluated according to the second and sixth level drawings of 2B[36003, and the 9-1 level is qualified. For annealed parts, the decarburized layer after annealing shall be inspected according to GR224. The degree of surface decarburization layer shall be less than one-third of the machining allowance on one side. 6.6 The microstructure shall be inspected according to the force method specified in GB/13398, and shall be displayed on the representative parts or samples of the parts. Mechanical properties
1 The mechanical properties of elastic parts meet the requirements. 2 The inspection methods of various mechanical properties shall comply with the relevant standards. 8 Deformation
! The deformation difference of the parts shall meet the requirements of the drawings or the specifications of the workmanship. 8.2 Parts with excessive deformation can generally be corrected. Parts with high precision requirements shall be subjected to stress relief treatment after correction. 0 Acceptance inspection rules
9.1 Parts shall meet the relevant indicators specified in the technical requirements to be qualified. 9.2 Appearance quality and surface hardness: Deformation is a must-check item. All parts in batches shall be inspected. The rest are detailed items. The inspection items shall be indicated in the process documents.
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