1. Counterfeit thick-walled seamless steel tube is prone to folding.Folding is the thick-walled seamless steel tube surface formed by a variety of broken lines, this defect is often throughout the longitudinal products.The reason for folding is that the manufacturer pursues high efficiency, the pressure is too big, the ear is produced, the next rolling will produce folding, folding products bending will crack, thick wall seamless steel tube strength decreased.
2. fake thick wall seamless steel pipe appearance often pockmarked.The pockmark is the irregular uneven defect on the surface of thick - walled seamless steel tube.Due to the counterfeit thick - walled seamless steel pipe manufacturers to pursue profits, often appear groove rolling most exceed the standard.
3. Fake thick wall seamless steel tube surface is prone to scar.
There are two reasons:
Fake thick wall seamless steel tube material is not uniform, more impurities.
Shoddy material manufacturers guide guard equipment is simple, easy to stick to steel, these impurities bite roll easy to produce scar.
4. The surface of fake and inferior materials is prone to crack, because its billet is adobe, which has many pores. In the process of cooling, the adobe is subjected to thermal stress, resulting in cracks and cracks after rolling.
5. Square moment tube describes that the counterfeit thick-walled seamless steel pipe is easy to scratch, the reason is that the manufacturer of fake and inferior materials is simple and simple equipment, easy to produce burr, scratch the surface of thick-walled seamless steel pipe.Deep scratches reduce the strength of thick - walled seamless steel tubes.
6. Fake thick-walled seamless steel tube without metallic luster, is light red or similar to the color of pig iron.
There are two reasons:
Its billet is adobe.
The fake rolling temperature is not standard, their steel temperature is visually measured, so can not be rolled in accordance with the provisions of the austenitic region, thick wall seamless steel tube performance naturally can not meet the standard.
7. seamless square pipe about the counterfeit thick wall seamless steel tube transverse bar thin and low, often appear dissatisfied with the phenomenon, the reason is that the manufacturer in order to achieve a large negative tolerance, the first few channels of the finished product under the pressure of large, small iron, hole filled with discontent.