This standard specifies the method for determining the depth of carbonitriding layer of sintered iron-based products by metallographic method. This standard is applicable to the determination of the depth of carbonitriding layer of sintered iron-based products. JB/T 7378-1994 Determination of the depth of carbonitriding layer of sintered iron-based products JB/T7378-1994 Standard download decompression password: www.bzxz.net

Machinery Industry Standard of the People's Republic of China
JB/T7378-94
Sintered iron-based products
Determination of carbonitriding layer depth
Published on July 26, 1994
Ministry of Machinery Industry of the People's Republic of China
Implementation on July 1, 1995
Mechanical Industry Standard of the People's Republic of China
Sintered iron-based products
Determination of carbonitriding layer depth
Subject content and scope of application
This standard specifies the method for determining the carbonitriding layer depth of sintered iron-based products by metallographic method. This standard is applicable to the determination of the carbonitriding layer depth of sintered iron-based products. 2 Reference standards
GB5163 Determination of density of permeable sintered metal materials 3 Terminology
3.1 Depth of carbonitriding layer
JB/T7378--94
The total depth from the surface of the carbonitriding layer to the place where the core structure is completely presented, including the hypereutectoid layer, eutectoid layer and transition layer. 4 Preparation of samples
4.1 The sample should be cut from the cross section of the carbonitriding product. When sampling and grinding the sample, the measured surface shall not change its structure or hardness due to heat or work hardening.
4.2 The sample should be tempered at 450℃, kept warm for 20 minutes and then cooled to room temperature. 4.3 To prevent the end of the sample from being rounded, the sample can be embedded in a steel ring or steel clamp, or it can be cured with epoxy resin glue. 4.4 Others Grind, polish, rinse and blow dry according to the metallographic sample preparation method. 5 Method for measuring the depth of carbonitriding layer under medium-temperature tempering 5.1 Etch with 2%~4% nitric acid alcohol solution. 5.2 The depth of carbonitriding layer should be measured under 100 times magnification. 5.3 The measuring position should be the working surface of the part. There should be at least three measuring points. 5.4 Measure from the surface of the sample carburizing layer to the place where the core structure is completely presented. If the boundary of the carburizing layer is not obvious, measure to half of the transition layer. 6 Method for measuring the depth of carbonitriding layer under quenching 6.1 When the carbon content of the core structure is low and the density is greater than 6.5g/cm, the depth of carbonitriding layer can be measured under quenching. 6.2 The density of the sample is determined according to GB5163.
Test report
The test report should include the following contents:www.bzxz.net
Sample name, number, production date, inspection date; a.
Heat treatment process parameters and technical requirements;
Measurement method, measurement position and its measurement results, factors that may affect the results and additional instructions. Approved by the Ministry of Machinery Industry on July 26, 1994
Implemented on July 1, 1995
Additional Notes:
JB/T7378-94
This standard was proposed and managed by Beijing Powder Metallurgy Research Institute. This standard was drafted by the Radiator Factory of the First Automobile Works. The main drafters of this standard were Li Xikui, Liu Guilan and Zhou Xisheng.
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