Questions about steel grades
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Today I read about the grades of high-quality carbon structural steel and low-alloy steel, and there’s one thing I’m not quite sure about. For example, high-quality carbon structural steel has a grade called 40Mn, while low-alloy steel has a grade called 20Cr. So how can I tell which one is high-quality carbon structural steel and which one is low-alloy steel? Also, in the book on the fundamentals of chemical engineering equipment compiled by Teacher Wang Liye, when discussing the notation for steel grades, these are divided into four categories: ordinary carbon steel, high-quality carbon steel, low-alloy steel, and steel with special properties. But why is the grade Cr22Ni14N also referred to as austenitic steel? Does austenitic steel belong to steel with special properties? How can one distinguish between austenitic steel and austenitic stainless steel based on their grades?
No one is answering? I’m really curious to know
In the alloy composition, the number before it represents the carbon content, while the number that follows indicates the amount of alloying elements present. Only when there is a sufficient amount of alloying elements can it be called alloy steel. Austenitic stainless steel refers to those with a chromium content of 8-18%
Reply to 3# madaha8888: Thank you for your reply, but I still don’t quite understand. In 40Mn and 20Cr, the number after Mn and Cr is both 1; why is one a high-quality carbon steel while the other is a low-alloy steel?
I think it’s better to read the books by yourself, as that will leave a deeper impression; Mn and Cr are different
You can take a look at the materials on metallography