Standard API | ASTM | BS | DIN | DNV | GB | ISO | JIS | KS | LR | NF | Others ASTM Standard Number A 731 (Seamless and Welded Ferritic Stainless Steel Pipe) Grade 18Gr2Mo TPXM33 TPXM27 TP439 29-4 29-4-2 26-3-3 S41500 [ All grade ]