... ST45-4/8),45#(DIN CK45),16mn(ST52.4) etc.b. JIS Standard10#(STPG38,STS38,STB30,STB33,Stb35), 20#(STPG42 ... AISI Standard10#(ASTM a106/53 Gr.B,A192,A179-C),20#(ASTM A106/53 Gr.B, A178-C,A210-A-1 ... ,A315-B,AISI1020),45#(AISI1045), 16mn(ASTM A210-C) etc.Usageboiler use,water transport, building, machinery, traffic, aviation, ... to let us know, thanks ASTM A106 Grade B carbon seamless steel pipe