. . .
ASTM ASME
ST37 ST52
12 Cr Mo 15 Cr Mo
1/2"~24", DN15~DN600 OD21.3MM~609.6MM
GB/T3091-2008, API SPEC 5L
Q195, Q215, Q235, Q345B, X42, X52, X60
Hebei Yanshan County Electricity . tee . . .