i`m writing an ASME IX WPS. The material is an AISI 4130 Pipe. I cant find a P number or equivalent for

this material. I finded in Asme II a classification for SA-519 gr.4130 This is the type and grade, but, in

Asme VIII, or ASME IX, i can`t find this SA. Anyone has any background to share about this?

there's no AISI 4130 pipe material. As Al has perfectly explained, AISI standards (AISI is the American

Institute of Steel and Iron) simply states the chemical composition of a certain steel identified by

a number. In this case, the number is 4130.

American standards covering pipe materials are ASTM, ASME Section II, API, AWWA. If there's another

one, I don't know. ASME Section VIII covers pressure vessels, not pipe. ASME Section IX rules the

approval of welding procedures and welders. Pipe materials are also covered by ISO standards, but I'm

not familiar with them.

So, chances are that the piping you're talking about is actually SA 519 Gr. 4130. SA means an ASME

Section II material. The majority of SA materials are identical to ASTM ones, the only difference being

the letter S before the letter A, which ASTM doesn't have.

P numbers include steels of similar chemical composition and mechanical properties, from which you

can expect similar behavior. Welding procedures for the same P numbers are the same, or very close to

each other.

I've taken a look at the chemical composition of AISI 4130 and ASTM A-519 Gr. 4130 steels and they're

exactly the same.

C: 0,28 - 0,33. Mn: 0,4 - 0,6. Si: 0,2 - 0,35. Cr: 0,8 - 1,10. Mo: 0,15 - 0,25. P and S as low as possible.

So, the P number you're looking for is the one for SA-519 Gr. 4130.