Classified by wall thickness - extra thick walled rectangular tubes, thick walled rectangular tubes and thin-walled rectangular tubes Executable standards:GB / t6728-2002, GB / t6725-2002, gbt3094-2000, JG 178-2005, ASTM A500, JIS g3466, en10210 or technical agreement application fields: widely used in machinery manufacturing, construction industry, metallurgical industry, agricultural vehicles, agricultural greenhouse, automobile industry, railway, highway guardrail, container frame, furniture, decoration and steel structure, etc.