Differences beween 15Mo3 and 16Mo3 1

[etsen]

I am confused when it comes to 15Mo3 and 16Mo3 for seamless tube and shell of pressure vessel respectively, for both of their steel number are 1.5415. Could anyone explain for me or recommend some books or articles for me to read? And is there ASME steels equivalent to 15Mo3 and 16Mo3 respectively? Thanks a lot.

 

[ulyssess]

For plates:
15Mo3 was the designation in DIN 17155, replaced in 1993 by EN 10028-2. At the same time, the name was changed to 16Mo3, maintaining the steel number 1.5415. There are small differences in minimum values between both.
As fat as I know there is no exact equivalent steel grade in ASME. The nearest is SA 204 Grade A with 0,5%Mo (against 0,3% for 16Mo3)