1. The composition of the high-quality thick-walled seamless pipe is uniform, the tonnage of the cold shear is high, and the end face of the cutting head is smooth and neat. However, due to the poor material, the end face of the cutting head often has a phenomenon of flesh, that is, unevenness, and no Metallic luster. Moreover, due to the fact that the manufacturers of fake and inferior materials have fewer cuts, big ears will appear at the head and tail.
2. The inferior thick-walled seamless pipe has no metallic luster, and is light red or similar to pig iron. There are two reasons for its billet is that the temperature of rolling the inferior and shoddy materials is not standard, and their steel temperature is visually checked. Rolling according to the specified austenite area, the performance of the thick-walled seamless pipe naturally cannot reach the standard.
3. The material of fake and inferior thick-walled seamless pipe contains many impurities, the density of the steel is relatively small, and the size is seriously out of tolerance, so in the case of no vernier caliper, it can be weighed and checked.
4. The cross-section of the inferior thick-walled seamless pipe is oval, because the manufacturer reduces the amount of the first two passes of the finished roll in order to save materials. The strength of this rebar is greatly reduced, and it is not in line with the rebar. The standard of external dimensions.
5. The surface of the inferior thick wall seamless tube is prone to scars. There are two reasons:
① The inferior and thick thick-walled seamless pipes are made of uneven materials and have many impurities.
②The guide and guard equipment of the manufacturers of fake and inferior materials is simple and easy to stick to steel. These impurities are prone to scars after biting the roller.
6. The surface of the inferior and inferior materials is prone to cracks, because its billet is adobe, and the adobe has many pores, and the adobe is cracked due to thermal stress during the cooling process, and it will have cracks after rolling.
These are the six methods we use to distinguish between seamless and good in production and life. Only by knowing and understanding these can we choose the good and reasonably priced pipes produced by good seamless pipe manufacturers.