... 3.percentage elongation and the strength are ideal 4.NBK 5.NDT carbon steel tubethe manufacturing standard adopted for this product is ... structure device.specification: Outside Diameter:4-114mm Wall Thickness:0.5-6mmStandard:Din2391 Din17175 Din-EN-10305-1 Din1629 Din73000 etc ... ,200,210,213,333,335,500,519,556,587) etc. carbon steel tube