API 5L, GR.B,X42,X46,52,X56,X60,X65,X70
API 5L Standard aims to gas and water in oil and gas industry for reference, which is used for seamless steel pipe and welded steel pipe, including common port and port, pipe socket port and direct stream tube (TFL) and port has for a particular connection tube processing. API 5L Standard is including steel grade(GR.B,X42,X46,52,X56,X60,X65,X70).