This standard specifies the technical requirements, inspection methods and acceptance rules for carburizing and carbonitriding, quenching and tempering of metal cutting machine tool parts. This standard is applicable to carbon structural steel, alloy structural steel and other parts with a carbon content of less than 0.30% after carburizing and carbonitriding, quenching and tempering. JB/T 8491.4-1996 Technical conditions for heat treatment of machine tool parts Carburizing and carbonitriding, quenching and tempering JB/T8491.4-1996 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
JB/T 8491.4-1996
Technical Conditions for Heat Treatment of Machine Tool Parts
Carburizing and Carbonitriding, Quenching and Tempering
1996-11-07 Issued by the Ministry of Machinery Industry of the People's Republic of China in January 1997 and implemented by IB/T8491.4-1996. This standard is formulated on the basis of summarizing our many years of experience in the treatment of machine tool parts and referring to relevant foreign technical data. This standard replaces JBT54218-94 "General Technical Conditions for Carbonization, Carbon Refining and Tempering of Machine Tool Parts". This standard is proposed by the Technical Committee for Standardization of Cutting Machine Tools. This standard is submitted by the Beijing Machine Tool Research Institute of the Ministry of Machinery Industry. This standard is issued by the Beijing Machine Tool Research Institute of the Ministry of Machinery Industry. This standard was first issued in 1994. Machinery Industry Standard of the People's Republic of China. Technical Conditions for Heat Treatment of Machine Tool Parts. Carbon and Carbon Refining, Quenching and Tempering. JE/T 8491.4 --- 1996bZxz.net
Civilization No. 5421844
This standard specifies the technical requirements, inspection methods and some rules for the carbonitriding, annealing and tempering of metal cutting machine parts (including simple parts).
This standard is applicable to carbon structural steel, alloy structural steel and other zero-carbon steel with a carbon content of less than 0.30% after annealing and carbonitriding, annealing and tempering.
Cited Standards
The provisions contained in the following standards are incorporated into the provisions of this standard by reference in this standard. At the time of publication of this standard, the versions shown are valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the standard, GB230-91
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ZB104001-83Automobile magnetic gear metallographic inspectionNJ 30583
3 Appearance quality
Carbon transfer gears should be clean, and no cracks, burns, pits, bumps, etc. are allowed. 3.2 Inspection of appearance Observe with naked eyes or low-power microscope. When the appearance is not good, sandblasting or flaw detection can be used. 4 Surface hardness
4.1 The surface roughness of the parts should comply with the requirements of the drawings and the actual process. The surface roughness difference is one HRC, 4.2 The station is equal to the matching parts The hardness is generally not more than 35HRC. 4.3 The test shall be carried out according to the method specified in GB330. The representative working shell surface of the parts shall be measured. When the specified method is not suitable, other hardness test methods may also be used: 5 Effective hardening layer depth 5.1 The effective hardening layer depth of the parts shall comply with the provisions of the technical documents and the effective hardening layer depth deviation is shown in Table 1. Approved by the Ministry of Machinery Industry on November 7, 1996, implemented on January 1, 1997, the effective hardening layer depth of the parts shall be consistent and shall not exceed the provisions of Table 2. The effective hardening layer depth of the parts ... 5.3 The effective hardening layer thickness limit is 550HV1#
Public Education Shenzhen Institute
Shenzhen Flag Plate
5.4 The effective hardening layer thickness is tested according to the method specified in GB9450. The depth difference is measured by using a furnace sample. 6.1 After the whole and unloading co-penetration, the microstructure of the surface of the layer is not in accordance with the carbide level diagram of 20Ct20CrMnTi steel after carbon filtration in the "Metallurgical Inspection Illustrations for Machine Tool Pins and Nitrogen Treatment", and 1-4 levels are qualified. The core grain size of the parts after magnetic permeation and carbonitriding is tested according to UB6394, and 5-8 levels are qualified. 6.1
After the latent reduction and floating fire[3 fire, the microstructure of the surface of the fallen layer shall be evaluated according to 2BTU4001, and 1-4 levels are qualified. 6.3
6.4 The microstructure of the paint layer surface shall be evaluated according to N305, and [5 levels are qualified. 6.5 The visible structure after carbonization, rate of infiltration and tempering shall be evaluated according to JB2782, and [-$ levels are qualified. 6.6 Inspection of microstructures shall be carried out on the same furnace samples according to the method specified in GB/T13298. When there is any objection, it shall be observed on the test piece. 1. The deformation of the parts shall be as specified in the drawing or the technical documents. 2. Parts with abnormal shape can be inspected. Parts with high requirements for stability shall be inspected. The stoppers shall be removed. 8. Acceptance rules
.1 The parts shall be qualified only when they meet the relevant indicators specified in the technical requirements: 8.2 External quality, surface hardness, deformation, effective hardening depth are mandatory inspection items. After each furnace, the parts shall be inspected. The other inspection items shall be clearly stated in the technical documents. 2
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