1. Shoddy steel pipe prone to folding.
Folding is the formation of a variety of steel pipe surface line, this defect often runs through the entire product vertical. The reason for folding is due to the pursuit of high efficiency shoddy manufacturers, the amount of pressure is too large, resulting in ears, the next rolling to produce folding, folded products will be cracking after bending, steel strength decreased.
2. Shoddy steel pipe surface often have Ma surface phenomenon.
Ma surface is due to rolling groove wear caused serious irregular irregularities of steel surface defects. As the shoddy steel pipe manufacturers to pursue profits, rolling groove rolling is often the most excessive.
3. Fake steel pipe surface prone to scarring. There are two reasons: (1). Shabby steel pipe material is uneven, many impurities. (2). Shoddy material manufacturers Guiding poorly equipped, easy to stick steel, these impurities bite after the roll is easy to produce scarring.
4. Pseudo-inferior material is easy to produce cracks on the surface, because its blank is adobe, adobe pores, adobe in the cooling process due to the role of thermal stress, cracks, after rolling cracks.
5. Shoddy steel pipe easy to scratch, because the shabby steel pipe manufacturers simple, easy to produce glitches, scratch the surface of steel. Deep scratches reduce the strength of the steel.
6. Shabby steel pipe without metallic luster, light red or similar pig iron color, for two reasons, its blank is adobe. 2, the temperature of non-standard rolling of shoddy materials, their steel temperature is through the visual, so that the provisions of the austenitic region can not be rolled, the performance of natural steel can not be achieved.
7. Shabby steel tube of fine and low, often appear dissatisfied with the phenomenon, because the manufacturers to achieve a large negative tolerance, the finished product before a few Road, the amount of pressure is too large, iron type is too small, hole filling dissatisfaction.
8. Cross-section of the shoddy steel pipe is elliptical, because the manufacturers in order to save material, the finished product before the two roll down the volume is too large, the strength of this steel greatly reduced, but also does not meet the screw dimensions.