Have you ever faild the hardness of a standard hardening and tempering process, even though you have verified all the variables (hardening temperature, control of the atmosphere, type of material, etc) and for a request of 470 HB, obtain after hardening a hardness that does not even reach 400 HB?
Have you ever bought a certified material of the highest quality and fail to obtain the desired mechanical properties after heat treatment?
The characteristics are the same type of workpiece (same section 45 mm) produced with two different materials, 56Si7 (casting N has 1 and casting N 2) and 56SiCr7 (casting N 3). We preferred to perform the test in the same furnace load in order to avoid variations in the process conditions