ms square tube 1.steel grade: Q195-Q345,S235-S355 2. ... , S275MH, S275MLH, S355MH, S355MLH, S420MH, S420MLH, S460MH, S460MLH, TW.O, TS.O, STK290, STK400, STK490, STK500, STK540, STPG370, STPG410 etc..SurfaceSatiny ... ,square pipe3,square pipe4,square pipe,square pipe,square pipe ms square tube