Bad welding of spiral steel pipe identification method 1. Bad spiral steel tube folding is seen. Folding table is spiral steel tube surface form of all sorts of line, this kind of defect often throughout the entire product longitudinal.

Causes of fold is due to the pursuit of high efficiency, the inferior reduction slants big, handle, when the next rolling produce folding, folding products will be crack after bending, strength of steel.

2. The inferior spiral steel pipe scaffolding tube appearance often have pitted surface phenomenon. Pits was caused by worn groove steel irregular uneven defects. Because inferior spiral steel pipe manufacturer to pursuit of profit, often appear groove rolling the overweight.

3. The inferior spiral steel pipe surface are prone to scarring. There are two reasons:

(1) uneven inferior spiral steel pipe materials, impurities.

(2).Inferior material manufacturer guide equipment simple, easy to stick steel, these impurities after the roll bite are prone to scarring.

4. The surface of inferior material easy to 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. Inferior spiral steel pipe is easy to scratch, the reason is inferior spiral steel pipe factory equipment simple, easy to produce burr, scratch steel surfaces. Deep scratches to reduce the strength of the steel.

6. The inferior spiral steel pipe without metallic luster, reddish or similar to the color of the pig iron, two point two, its billet is adobe reasons.

7, 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.