Big Diameter Welded Pipes Grade:304/304l/316/316l/310s/321 Standards: ASTM A312/213/511,GB/T14975,GB/T14976, Big ... -temperature resistant3) The main standards are 304, 304L, 316, 316L, 321, 321H, 310S, 347H,3014) Size: OD (159- ) x (1-20 ... , boiler heat exchanger, and other fields Big Diameter Welded Pipes,seamless steel weldede pipe,welded steel pipe,stainless steel pipe