WYJ003-2001             P20

For the purpose of further regulating and unified precision plastic mould with applications series (718, 2738, 2311, DINO42 etc steel) steel plate hardness testing method, ensure plastic mould steel factory's product quality, applications of the steel plate series factory hardness test, according to this code provisions.

1. The hardness testing equipment: HLX-11 A leeb hardness tester made in huizhou.

2. Steel plate grinding and polishing equipment: portable surface grinding wheels and portable polishing machine.

3. Each steel plate in the provision of five parts for testing hardness test (see figure 1). When the above five parts of the hardness value which conform to the provisions of the supply technical conditions, steel plate hardness as qualified.

4. Each detection place has at least 3 point detection, with its average as the parts of the nominal hardness value.

5. Use the above five detection parts of the average value of the hardness measured as the nominal value of their hardness steel plate.

6. When a detection parts of the hardness value with other parts of the hardness value have obvious deviation, it should be choose another detection parts near to it to preceed the hardness testing.

7. The field detection hardness, steel temperature should be no more than 40 ℃.

8. Each test site must be approved by strict grinding, polishing area should be not less than 25 cm2, grinding depth see table 1.

Table 1       unit ：mm

9. The hardness testing parts of the grinding wheel must be approved by a portable plane coarse grinding, the laptop polishing machining process. Because the manufacturing quality testing of hardness testing results influence is bigger, therefore, the manufacturing quality testing must be up to level off, smooth, visual and feel no apparent concave-convex feeling greatly and deep scratches (general should achieve ▽more than 5).

10. The thickness of the steel plate test site should not be less than the minimum thickness of steel allowed.

11. Brinell hardness calibration, hardness tester detection method shall be in accordance with relevant standards and hardness tester for the requirements of the standard.

12. The inspection norms use only and 25 ~ 310 mm thick plate series applications.

13. Matters not, all in accordance with the corresponding relevant state hardness testing standards to execution.

14. The inspection specifications issued since the date of execution.