In the mechanical properties of heat-resistant steel, is the hardness the bigger the better?

In the mechanical properties of heat-resistant steel, the hardness is not the bigger the better.
The materials of various grades only need to meet the performance requirements. Pursuing too high hardness will not only bring economic increase, but also cause processing difficulties, and even reduce other mechanical properties.
Hardness is divided into: ① scratch hardness. It is mainly used to compare the softness and hardness of different minerals. The method is to choose a rod with one end hard and the other end soft, pass the material to be tested along the rod, and determine the hardness of the material to be tested according to the position of the scratch. Qualitatively speaking, hard objects make long scratches and soft objects make short scratches. ② Indentation hardness. Mainly used for metal materials, the method is to use a certain load to press the specified indenter into the material to be tested, and compare the softness and hardness of the material to be tested by the size of the local plastic deformation on the surface of the material. Due to the difference of indenter, load and load duration, there are many kinds of indentation hardness, mainly including Brinell hardness, Rockwell hardness, Vickers hardness and microhardness. ③ Rebound hardness. Mainly used for metal materials, the method is to make a special small hammer fall freely from a certain height to impact the sample of the material to be tested, and use the amount of strain energy stored (and then released) in the sample during the impact (through the return of the small hammer) jump height measurement) to determine the hardness of the material.