... seamless pipe for exchanger 2)OD3~114mm,L<=8000mm 3)ASTM B338 4)Gr1,Gr2,Gr3,Gr4,Gr5,Gr6,Gr12 ... BT1-0Technology StandardOut Diameter (mm)Wall Thickness(mm)ASTM B338,ASME SB338,ASTM B337ASTM B8613~50.2,0.3,0.5,0 ... 0.6,0.8,1.0,1.25,1.5>15~200.5,0.6,0.8,1.0,1. ... statestandardGR1GR2 GR3 GR7 GR12 >10~150.5~2.0MASTM B338>15~200.6~2.5M>20~300.6~3.0M>30 ... .5~1.25MASTM B338>10~150.5~1.5M>15~200.5~2.0M>20~300.5~2.0M