... Size:20x20-400x400mm. TCT:0.6-16.0mm steel mill 1)Material: Q195/Q215/Q235,20#,45# etc.2 ... , building and construction Industry, traffic andcommunication, and so on. Square Pipe Product nameSquare PipeSpecification20mm*20mm-400m*400mmMaterial of ... Hollow section 1m-12mProcessing techniquecoupling, necking, punching and so on.Usage industryPetrol, gas, water pipe,construction,chimney pot. ...