JB/T 9204-1999 JB/T 9204-1999 Metallographic examination of steel parts by induction heat treatment JB/T9204-1999 Standard download decompression password: www.bzxz.net

1CS 25. 200
Mechanical Industry Standard of the People's Republic of China
JB/T9204—1999
Metallographic examination of induction hardened steel parts1999-06-24 Issued
State Machinery Industry Bureau
2000-01-01 Implementation
JBT9204—1999
This standard is a revision of ZBJ36009—88 on induction quenching of steel parts, and the main technical contents have not changed. This standard replaces ZBJ36009—88 from the date of implementation. Metallographic examination of induction hardened steel parts1 Scope
This standard specifies the technical requirements and corresponding inspection methods for induction hardening metallographic examination of steel parts. JB/T9204-1999
Generation ZB J36 009-.-88
This standard applies to the inspection of metallographic structure and effective hardened layer depth of mechanical parts made of medium carbon structural steel and medium carbon alloy steel after high and medium frequency induction quenching.
2 Cited standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should discuss the possibility of using the latest version of the following standards. GB/T5617—1985 Determination of effective hardened layer depth of steel after induction quenching or flame quenching 3 Technical requirements
3.1 The surface hardness and effective hardened layer depth of parts shall comply with the provisions of the product drawings. 3.2 After quenching, there should be no defects such as cracks and burns on the surface. 3.3 After quenching and low-temperature tempering (≤200℃), the parts shall be tested according to the microstructure. The metallographic structure is evaluated according to the grading diagram (Figure 1 to Figure 10). The grading description is shown in Table 1.
When the lower limit of hardness specified in the drawing is higher than or equal to 55HRC, grades 3 to 9 are qualified. When the lower limit of hardness specified in the drawing is lower than 55HRC, grades 3 to 9 are qualified. 4 Sample preparation
4.1 Sampling location: Cut in the middle of the part's induced annealing area or cut according to the location specified in the part's technical conditions. There should be no tempering phenomenon during sampling. 4.2 After grinding, the metallographic sample is etched with an alcohol solution containing 2% to 5% nitric acid by volume until a clear hardened layer is displayed.
5 Inspection method
5.1 Effective hardened layer depth measurement method: After the part is annealed and tempered at low temperature, use a test force of 9.8N on a Vickers hardness testing machine to measure the specified location of the cross section perpendicular to the surface of the part. With the agreement of the relevant parties, 4.9~49 The test force in the range of N shall be measured in accordance with GB/T 5617. 5.2 The microstructure shall be measured at 400 times and inspected at the surface of the effective hardened layer. Approved by the State Bureau of Machinery Industry on June 24, 1999, implemented on January 1, 2000
Coarse martensite
Relatively coarse martensite
Martensite
Relatively fine martensite
Fine martensite
Microfine martensite
JB/T 9204-1999
Description of microstructure classification
Fine martensite with uneven carbon content
Fine martensite with uneven carbon content and a small amount of ultrafine pearlite (christite) + a small amount of ferrite (5%)
Fine martensite + network-like ultrafine pearlite (christite) + undissolved ferrite (<10%)
Fine martensite + network-like ultrafine pearlite (christite) + large blocks of undissolved ferrite (>10%)
Microstructure classification chart (400×)
Figure 1 level
Average area of ​​grains
Corresponding grain size
Figure 22 level
Figure 33 level
Figure 55 levelbzxZ.net
JB/T 9204—1999
Figure 44 level
Figure 66 level
Figure 77 level
Figure 99 level
JB/T 9204--1999
Figure 1010 level
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