Stainless steel pipe widely used in petroleum,chemical industry,electric power,boiler, SpecificationsAPI, ... ,70 Alloy Steel Butt Welding Pipe fitting:ASTM A234 WP1, WP12, WP11, WP22, WP5, WP7, WP8, and WP91 Stainless Steel Butt Welding Pipe fitting:ASME ... A403 WP304,304L,316,316L, 319, 310S, 321, 321H S304 ...