GB/T13793-2008 Q235C welded steel pipe use of cold-rolled process, Q235C welded steel pipe’s surface can be painted black paint, transparent oil, hot dip galvanized, 3PE, epoxy paint, BE, PE,Q235C welded steel pipe mainly used in machinery manufacturing, construction, metallurgical industry, agricultural greenhouse, automotive industry, construction, railway, highway guardrail, steel structure,good mechanical properties and mechanical properties