... petroleum and natural gas industry specially. 2. Be strict with tolerance. 3. Serve all over the world. 4 Inch Stainless ... Steel Pipe Steel Grade:304,304L,316,316L,321,317L,310S,904L and so on. ... Standards:ASTM,JIS,DIN,GB and so on. Delivery condition: ... petroleum, chemical, medical equipment, boiler heat-exchanger and other fields.