Hunan Standard Steel co.,Ltd Seamless steel pipe :OD 1/4 inch-30inch W.T 1.25mm to 50mm ERW steel pipe:OD 1/2inch-52inch W.T 1.65mm to 25mm LSAW steel pipe: OD 1/2inch-52inch W.T 1.65mm to 25mm Spirally welded steel pipe: 219mm to 3120mm .W.T 3mm to 25mm