DIN7300/DIN2391 seamless steel tube: steel grade: A135-A, 10#, A315-B, 20#, St37, St45 High Pressure Seamless Tube for Diesel EngineSteel grade: ... A135-A, 10#, A315-B, 20#, St37, St45 or low alloy steel;Standard: ... engine, gosling engine and automobile. Its feature is high precision of inner diameter, good inner bore cleanliness and low impurity ...