Spec: ASTM standard (American standard): ASTM A53 A/B, API 5L A/B/X42/X46, A106 A/B/C; JIS standard (Japanese standard): G3444 (1994): STK, G3452 (1988): SGP, G3454 (1988): STPG 370, STPG 410; G3456 (1988): STPT 38, STPT 42, STPT 49