steel tube

　　And inferior steel tube surface are prone to scarring. For two reasons: (1) and inferior steel pipe material uneven, impurities. (2). And inferior material manufacturer guide equipment simple, easy to stick steel, these impurities after the roll bite are prone to scarring. 4. Easy generation and inferior material surface crack, the reason is that it's blank is adobe, adobe air, adobe in the process of cooling due to the effect of thermal stress, cracks, after rolling there is crack. 5. Easy to scratch and inferior steel pipe, the reason is false and inferior steel pipe factory equipment simple, easy to produce burr, scratch steel surfaces. Deep scratches to reduce the strength of the steel. 6. No metallic luster and inferior steel tube, reddish or similar to the color of the pig iron, for two reasons: (1), the billet is adobe. (2), and inferior material rolling temperature is not standard, their steel temperature is through visual inspection, so can't austenitic area of the rolling by the regulation, the performance of the steel natural can't up to standard.