... 15-400*400mm 3.Grade:Q195,Q215,Q235,Q345 Square Steel PipeDimensions:15*15mm-400*400mm(1/2''* ... ASTM1017,ASTM1020Manufactured to meet ISO9001,ASTM,DIN,BS,GB and JIS requirements Applications:Widely used in construction structure , ... ,hall structure, airport structure ,sports apparatus and automotive partsPacking :In square bundlesO,D.(mm)W,T.(mm)O.D ... over the world in long run . black square steel tube