... :1mm-50mm 4)specification:according to... Type: Seamless Steel Grade Available: 1)Austenite Steel: 304, 304L, 316, 316L, 316Ti, 321, 321H 2 ... )Marten site Steel: 410, 420, 431 3)Duplex Steel: UNS S31803, S32205 4)Precipitations Hardening Steel: 17-4PH(UNS S17400 ... : prompt delivery according to quantity ASTM A106 20# carbon seamless steel pipe