IS 1239 Steel Pipes are made up of a mild steel material. The material has different grades. The three grades are Fe330, Fe410 and Fe450. The numbers indicate the minimum tensile strengths of the grades. They respectively have 330MPa, 410MPa and 450MPa minimum tensile strengths. The IS 1239 Steel Pipe is made up of carbon, manganese, phosphorus and sulfur. The sulfur and phosphorus content remain the same in all grades where the other elements change in quantities with the grades of the pipes.