1、GM DAEWOO Auto & Technology EDS Engineering, GM DAEWOO Auto & Technology. Standards METHOD FOR VICKERS HARDNESS TEST EDS-T-7120 ISSUED DATE: 1990. 05. 23 REVISED DATE: 2006. 05. 26 VERSION: 3 EDS-T-7120 METHOD FOR VICKERS HARDNESS TEST PAGE: 1/3 ISSUED DATE: 1990. 05. 23 REVISED DATE: 2006. 05. 26 V
2、ERSION: 3 GM DAEWOO Auto & Technology 1. SCOPE This standard specifies the method of vickers hardness test for matallic materials. In this case, this standard shall be applied to the test load ranging from 0.01kgf to 2kgf. 2. DEFINITIONS The vickers hardness value shall be calculated from the follow
3、ing formular and shall be the one left after the load to leave a pyramidal indentation in the test surface with the diamond indenter of the angle between opposite faces of 136is divided by the surface area calculated from the length of the diagonal at indentation. )W14*/“E1E= Hv : Vickers hardness P
4、 : Test load d : Mean length of the diagonals at indentation A : Angle between opposite faces of diamond indenter(136) Fig. 1 Indenter Fig. 2 Size of indentation 3. TEST PIECE 3.1. The test surface of the test piece shall be even in principle. 3.2. The test surface of the test piece shall have no fo
5、reign substances such as oil and oxidized substances on it. EDS-T-7120 METHOD FOR VICKERS HARDNESS TEST PAGE: 2/3 ISSUED DATE: 1990. 05. 23 REVISED DATE: 2006. 05. 26 VERSION: 3 GM DAEWOO Auto & Technology 3.3. The thickness of the test piece shall generally be at least 1.5 times the diagonal length
6、 of indentation. The opposite face of the test material shall not be deformed due to the indentation. 4. TESTER 4.1. The tester to be applied to vickers hardness test shall be proper for ISO 6507 and KS B 5525. 4.2. The tester shall be set up on a sufficiently stable baseplate and shall be worked by
7、 placing the axis of indenter in perpendicular direction. 4.3. When the main parts of the tester are disassembled, rebuilt or reset, the tester shall be used after being reconfirmed for its accuracy according to ISO 6507 and KS B 5525. 4.4. Even when being not relevant to the preceding clause, the t
8、ester shall be confirmed for the adequacy of its accuracy according to ISO 6507 and KS B 5525 at a definite interval, depending on the frequency of testing.4.5. The diamond indenter needs to be exchanged when abnormalities on the main parts such as damages on its front edge or top line are admitted.
9、 In this case, it shall be used after being checked for its accuracy according to ISO 6507 and KS B 5525. 5. TEST 5.1. Unless otherwise limited, the magnitude of the test load shall be allowed to select as large as possible. 5.2. The microscope had better be used for the measurement of the diagonal
10、length of indentation within the range of 20% 70% of the visual field. 5.3. In case to measure hardness, as a rule, the distance between the centers of two adjacent indentations shall be 4 times diagonal length, and the distance from the center of any indentation to an edge of the test piece shall b
11、e at least 2.5 times there of. In any case, the center of the position whose hardness is to be measured shall not be within the influences of already existing indentation and the edge of the test sample. 5.4. The test surface of the test piece shall be placed so as to be perpendicular to the mountin
12、g axis of the indenter. 5.5. The test load shall be applied to the indenter without shock and also shall be increased gradually to such an extent as capable of neglecting the error due to the inertia of moving part until the specified magnitude is attained. 5.6. The specified load shall be maintaine
13、d for 30 seconds. However, iron steels and non-ferrous alloys with high hardness may be maintained under the specified load for 1015 seconds. EDS-T-7120 METHOD FOR VICKERS HARDNESS TEST PAGE: 3/3 ISSUED DATE: 1990. 05. 23 REVISED DATE: 2006. 05. 26 VERSION: 3 GM DAEWOO Auto & Technology 6. MEASUREME
14、NT OF INDENTATION AND CALCULATION OF HARDNESS 6.1. After removing the test load completely, the diagonal lengths of indentation shall be measured. 6.2. The indentation shall be placed within both measuring lines of a microscope. 6.3. First, left measuring line shall be correctly placed in contact wi
15、th left end point of indentation. 6.4. Right measuring line also shall be placed in contact with right end point of indentation. 6.5. After measurement, the diagonal length after the turn of 90shall be measured with the same method 6.6. Hardness value shall be calculated from the mean value of both
16、values above. Fig. 3 Measuring Method of the Size of Indentation 6.7. The hardness value shall be rounded off to first integral number in principle and the next place number shall conform to KS A 0021. 6.8. When it is necessary to indicate the test load at hardness value, it shall be affixed as illu
17、strated below. Ex) In case a hardness of 250 under a test load of 1kgf, indicate as 250 Hv1. Ex) In case a hardness of 500 under a test load of 0.3kgf, indicate as 500 Hv0.3. 7. RELATED SPECS 7.1. KS B 0811 VICKERS HARDNESS TEST TEST METHOD 7.2. OPEL 102 HARDNESS TESTING ACCORDING TO VICKERS 7.3. KS B 5525 VICKERS HARDNESS TESTING MACHINES 7.4. KS A 0021 RULES FOR ROUNDING OF NUMERICAL VALUES 7.5. ISO 6507 METALLIC MATERIALS HARDNESS TEST VICKERS TEST
