square&rectangular steel tube Material:Q195 Q235 Q345 St52 10# 20# Standard:BS JIS ... ASTM DIN Certification:CE,BV,SGS,API carbon square steel tube We can supply the high quality steel pipe and the ... .,Ltd AmandaTel: 86-0315-2247360Fax: 86-0315-2247325Skype:amandawang08 square&rectangular steel tube