The results of hardness testing can reflect the differences in chemical composition, organizational structure and processing technology of materials under certain conditions:
Inspecting raw materials,
Supervising the correctness of heat treatment processes,
Studying solid phase change processes,
Studying new materials, new alloys, etc.
Hardness testing is used for quality control in process management and production:
Hardness testing is performed on unheat-treated specimens to avoid mixing and wrong materials.
Hardness testing supervises the processing process: Avoid excessive cutting or grinding, which may cause annealing and change the performance.
When studying metal welding structures, hardness testing determines the tendency of welds to produce hardening, as well as the heat-affected zone:
Surface Rockwell and Vickers hardness methods measure the surface heat treatment strengthening effect and hardness gradient, and the depth of the surface strengthening layer or penetration layer.
Microhardness testing is a supplement to metallographic analysis methods, measuring the hardness of phases in microstructures.
The role of hardness testing in ensuring product quality and improving processes:
For example, if the hardness of a bearing is too high, it is prone to brittle cracking; if the hardness is too low, it is prone to wear and deformation; the right amount of hardness can greatly extend the life of the bearing.
During the processing, 5% to 10% of the samples need to be tested for hardness, that is, intermediate testing, to check the correctness of the processing technology and ensure the processing quality.
Hardness testing has become an important means of testing product quality:
A large jet airliner has thousands of parts that require hardness testing,
A car has hundreds of parts that require hardness testing,
A watch with only more than 100 parts also has more than 70 parts that need hardness testing.
Hardness has a certain relationship with the chemical composition, heat treatment conditions and metallographic structure of the material,
so hardness testing is also an important means of physical and chemical analysis and metallographic research.
In short, in the machinery manufacturing, metallurgy, precision instrumentation and other industries, from production to scientific research, from material selection, processing to finished product acceptance, hardness testing is an indispensable means, especially the development of modern materials science is closely related to hardness testing.
