Popular science: S39042 super stainless steel, what is S39042?

Rarely, UNS S39042 is domestic super stainless steel, similar to imported UNS N08904, yes, it is the famous 904L.

The S39042 super stainless steel GB 245 1 1 standard wide plate and Asmi alloy produced by TISCO have been successfully delivered to users.

Here is a brief introduction to the evolution history of 904L in the national standard system.

Let's start with S3 1782 in GB/T GB20878-2007, not 3 17L. S3 1782 is N08904 904L super stainless steel, and the domestic brand is 015cr21ni26mo5cu2.

Not long after that, in the 2009 edition of GB 245 1 1, 015cr21ni26mo5cu2 has a new identity: S39042. This is completely different from the naming of S3 1782 in GB/T20878-2007. Asmi Alloy thinks that the naming of S39042 contains the word 904, which may be because the Standard Committee is similar to 904L in ASME SA240 for convenience of memory, and it is a kind of customary "bringing order out of chaos".

After reading the above introduction, you can tell me why the next time you meet S39042!