The pipes are widely used in the fields of petroleum,construction,bilers ship building,mechanic,chemical and so on. The main standards are API(A,B,*42,*46,*52,J55,K55,N80), ASTM/ASME(A53,A106,A179,A192,A210,A333,A519), DIN(St37.0,St44.0,St52.0,St35.8,St45.8,15Mo3,13CrMo44,St35,St45,St52), EN(EN10216-1,EN10216-2,EN10305),JIS,BS,GB etc.