This standard specifies the selection and preparation of specimens, evaluation methods, standard rating charts, test reports, etc. for the microscopic evaluation method of eutectic carbide inhomogeneity of steel. This standard is applicable to the microscopic evaluation of eutectic carbide inhomogeneity in Leideite-type high-speed tool steel, alloy tool steel, high-carbon chromium stainless bearing steel, high-temperature bearing steel and high-temperature stainless bearing steel that have been deformed by pressure processing. GB/T 14979-1994 Method for evaluating the inhomogeneity of eutectic carbides in steel GB/T14979-1994 Standard download decompression password: www.bzxz.net

UDC 669. 112.224
National Standard of the People's Republic of China
GB/T 1497994
Eutectic carbide of steel.Micrographic method using standard diagramsIssued on 1994-06-13
Implemented on 1995-01-01
Issued by the State Bureau of Technical Supervision
National Standard of the People's Republic of China
Eutectic carbide of steel - Micrographic method using standard diagrams1 Subject content and scope of application
GB/T 74979—94
This standard specifies the selection and preparation of specimens, evaluation method, standard rating diagram, test report, etc. for the microscopic evaluation method for eutectic carbide inhomogeneity of steel.
This standard is applicable to the microscopic evaluation of the unevenness of eutectic carbides in the pressure-processed and deformed Leidenstein-type high-speed tool steel, alloy tool steel, high-carbon chromium stainless bearing steel, bearing steel and high-temperature stainless bearing steel. Reference Standards
GB/T13298 Metallic Microstructure Inspection Methods 3 Selection and Preparation of Samples
3.1 Sampling Quantity and Location
The sampling quantity and location shall be in accordance with the corresponding product standards or relevant agreements. 3.2 Sampling Method
Cut a transverse sample with a thickness of 10 to 12 mm from the steel (or steel bar) in the delivery state, and then cut the sample according to the sampling diagram recommended in this standard to ensure that the test surface of the sample is a longitudinal section through the diameter of the round steel, the diagonal of the square steel or the flat steel. 3.2.1 Round steel shall be cut according to Figure 1, Figure 2 and Figure 3, 10-12mm
Figure 1 Sampling diagram of round steel with diameter ≤ 25mm
Guohao Technical Supervision Bureau approved on June 13, 1994 and implemented on January 1, 1995
GB/T 14979-94
Figure 2 Sampling diagram of round steel with diameter 25~60mm
Card diameter
Figure 3 Sample diagram of mesh steel with diameter 60mm
3.2.2 Cut with square saw according to Figure 4, Figure 5 and Figure 6. 12mm
10-12mm
GB/T14979-94
Figure 4 Sampling diagram of square steel with reverse length ≤25mm
Figure 5 Sampling diagram of square steel with reverse length 25~60mm
10-12mm
And the current
Figure 6 Sampling diagram of square steel with side length>60mm
3.2.3 Flat steel is cut according to Figures 7 and 8. Steel plates and steel strips can refer to Figures 7 and 8. 1/2 reduction
1/4 slow place
《Ninghou Medical Place》
1/4 fine ship good
（1/4 thick virtual place】
3.3 Inspection status of the sample
GB/T 14979-94
Cloud edge length
12~15mm
Thickness≤30mm
Flat steel sampling diagram
Green education edge length
12-15mm
Thickness>Wmm
Fan steel sampling diagram
The inspection state of the sample is annealed state.
Note: The annealed state is also allowed when necessary. 3.4 Sample preparation
The sample preparation should comply with the requirements of GB/T13298. 3.5 Corrosion of the sample
3.5.1 Corrosive agent
The corrosive agent for high-speed tool steel, alloy tool steel and high-temperature bearing steel is recommended to be 4% 10% nitric acid alcohol solution or 5% nitric acid water solution 4
GB/T 14979-94
For high carbon chromium stainless bearing steel and high temperature stainless bearing copper, one of the following three types of etchants is recommended: a. Ferric chloride hydrochloric acid aqueous solution
20g ferric chloride, 20-30mmL hydrochloric acid, 100mL water, b. Saturated picric acid hydrochloric acid alcohol solution
20mL hydrochloric acid, 100mL alcohol, picric acid added to saturation. C. Sulfuric acid hydrochloric acid aqueous solution
4g copper sulfate + 20mL hydrochloric acid, 20mL water.
3. 5. 2 Corrosion method
The sample should be etched to dark gray, and the eutectic carbide should be clearly displayed. 4 Evaluation method
4.1 Inspection surface and inspection part
4. 1.1 The inspection surface is a velvet cross section.
4.1.2 Inspection location
4.1.2.1 Round steel is at one-quarter of the diameter, square steel and flat steel are at one-quarter of the diagonal. 4.1.2.2 According to the agreement between the two parties, high-speed tool steel, high-temperature stainless bearing steel, alloy engineer steel plate with a thickness of less than 4mm and steel wire with a diameter of less than Bmm can be inspected in the worst field from the edge to the center area. 4.1.2.3 According to the agreement between the two parties, high-carbon chromium stainless bearing steel and high-temperature bearing steel can be inspected in the worst field from one-quarter of the diameter to the center.
4.2 Magnification
The magnification is 100 times, and 9 is also allowed. 0～110 times. In arbitration, it must be 100 times. 4.3 Rating principles
For eutectic carbides in network form, the deformation, integrity and accumulation of carbides on the network are mainly considered: for eutectic carbides in strip form, the width of the strip and the degree of carbide nesting in the strip are mainly considered. 4.4 Result evaluation
Select the field with the most serious unevenness of eutectic embedding in the specified test position and compare it with the corresponding rating picture to evaluate the result. The evaluation result is expressed in a grade number. When eutectic carbides with no or little deformation are found during the test, if there are requirements in the product standard or agreement, they should be recorded in the test report.
5 Rating pictures
This standard adopts a total of six sets of rating pictures (see Appendix A). When using, they are selected according to the steel type and specification. 5.1 The first rating picture is applicable to hot-rolled, forged and cold-drawn high-speed tool steel bars and plates with a diameter, side length or thickness not exceeding 120mm.
5.2 The second rating chart is applicable to hot-rolled, forged and cold-drawn molybdenum-based commercial high-speed tool steel, high-temperature stainless bearing steel, steel bars and steel plates with a diameter, side length or thickness of not more than 120mm.
5.3 The third rating chart is applicable to high-speed tool forgings with a diameter greater than or equal to 120mm. 5.4 The fourth rating chart is applicable to hot-rolled, forged and cold-drawn alloy tool steels. 5.5 The fifth rating chart is applicable to hot-rolled, forged and cold-drawn high-carbon chromium stainless bearing steels. 5.6 The third rating chart is applicable to high-temperature bearing steels. 6 Test report
The test report should include the following contents: 6
This standard number:
Steel type and furnace number, specification 1
Sampling method, inspection surface, inspection location, selected standard rating chart:
Test results,
Test report number and date;
Tester.
GE/T 1 4979- 94
See Figure A1 for the first rating chart.
See Figure A2 for the second rating chart. www.bzxz.net
See Figure A3 for the second rating chart.
See Figure A4 for the fourth rating chart.
See Figure A5 for the fifth rating chart.
See Figure A6 for the sixth rating chart.
GB/T 14979—94
Standard rating chart
(supplement)
GB/T 1 4979—94
First rating chart
Technical crystal carbide uniformity 100×)
GB/T14979-94
Continued Figure A1
GB/T 14979—94
Continued Figure A1
GE/T14979—94
Continued Figure AI
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