Testing Method for Hardness of Stamping Parts

Stamping parts are the most commonly used parts in the field of metal processing and mechanical manufacturing. Stamping parts processing is a processing method that uses molds to separate or form metal strips. Its application range is very wide.

Stamping parts processing includes punching, bending, drawing, forming, finishing and other processes. The materials for stamping parts processing are mainly hot-rolled or cold-rolled (mainly cold-rolled) metal strip materials, such as carbon steel plates, alloy steel plates, spring steel plates, galvanized plates, tin-plated plates, stainless steel plates, copper and copper alloy plates, aluminum and aluminum alloy plates, etc.

The hardness test of metal materials is of great significance in the process of stamping parts processing. The hardness test of the stamping industry can be divided into the following three parts:

1. Inspection of raw materials entering the factory.

2. Hardness test of molds.

3. Hardness test of stamping intermediate products and stamping finished products.

The main purpose of hardness testing of stamping materials is to determine whether the annealing degree of the purchased metal sheet is suitable for the subsequent stamping processing. Different types of stamping processing require plates of different hardness levels.

1 Hot-rolled steel plate

Hot-rolled steel plates are usually thicker, and steel standards generally stipulate that Brinell hardness testers are used to test hardness.

It is also feasible to use Rockwell hardness testers to test hot-rolled steel plates, and HRB scales can be used.

2 Cold-rolled steel plates for stamping processing

Various cold-rolled steel plates used for stamping processing are mainly tested for hardness using Rockwell hardness testers, usually using HRB scales, and harder ones using HRC scales.

Thin plate materials can be tested with Vickers hardness testers, or with surface Rockwell hardness testers HRN or HRT scales.

3 Brass plates

The hardness of brass plates used for stamping processing can be tested with the HRB scale of Rockwell hardness testers.

Softer brass plates and copper plates use HRF scales.

Thinner plates use HRT scales.

4 Aluminum alloy plates for stamping parts processing

Aluminum alloy plates used for stamping parts processing can be tested with a Webster hardness tester. When the material thickness is greater than 13 mm, a Barcol hardness tester can be used instead.

Pure aluminum plates or low-hardness aluminum alloy plates should use a Barcol hardness tester.

5 Ultra-thin plates

Various metal ultra-thin plates used for stamping parts processing can be tested for HR30Tm hardness values ​​using the HR30T scale of the surface Rockwell hardness tester and a diamond point anvil.

The thickness of the tested thin plate can be less than 0.05mm. This test method is specified in Appendix A of the national standard GB/T 230.1-2004. The HR15T and HR45T scales of the surface Rockwell hardness can also be used, and the hardness value can be converted to HR30Tm after testing.