How to judge the quality of 4Cr material? I have a 4Cr 18 round steel wrapped by Baotou Steel, which has cracks after heat treatment. What's the matter? Is the material bad?

You have to talk about the heat treatment process and the shape of cracks ~ Generally speaking, reducing the cracking tendency can quench the oil or lower the quenching temperature; Of course, decarburization during heat treatment is also prone to cobweb cracking, and it is also easy to crack if it is not tempered in time after quenching. To identify the quality of steel is to look at the metallographic structure, do impact and tension, and compare it with the national standard.