ms square tube 1.steel grade: Q195-Q345,S235-S355 ... , JISG3454 etc.Grade10#-45#, 16Mn, A53-A369, API J55-API P110, ST35-ST52, Q195-Q345, 20#, 16Mn, ... L360M, L390M, L415M, L450M, L485M, L555M, L625M, L690M, H40, J55, K55, M65, L80, C95, N80, C90, T95, P110, , ... petroleum and natural gas industries,for use as casing and tubing for wells, screwed and socketed steel ... square pipe,square pipe ms square tube