... ,ST35-8),20#(ST42,ST45-4/8),45#(DIN CK45),16mn(ST52.4) etc.b. JIS Standard10#(STPG38,STS38,STB30 ... Stb35), 20#(STPG42,STB42,STS42,JIS S20C),45#(JIS S45C), 16mn(STS49,STPT49) etc.c. ASTM/AISI Standard10#(ASTM a106/ ... A178-C,A210-A-1,A315-B,AISI1020),45#(AISI1045), 16mn(ASTM A210-C) etc.Usageboiler use,water transport, building, ... to let us know, thanks ASTM A106 Grade B carbon seamless steel pipe