How to identify fake and inferior thick walled seamless square pipes? Let's follow the editor of the seamless square tube manufacturer to learn and learn together
1. Fake and inferior thick walled seamless steel pipes are prone to folding. Folding is a variety of creases formed on the surface of thick walled seamless steel pipes, which often run through the longitudinal direction of the entire product. The reason for the occurrence of folding is due to the pursuit of high efficiency by counterfeit and inferior manufacturers, resulting in excessive reduction and the generation of ears. Folding occurs during the next rolling process, and the folded product will crack after bending, resulting in a significant decrease in the strength of thick walled seamless steel pipes.
2. The appearance of fake and inferior thick walled seamless steel pipes often has pitted surfaces. Pitted surface is a defect caused by severe wear and tear on the rolling groove, resulting in irregular unevenness on the surface of thick walled seamless steel pipes. Due to the pursuit of profit by manufacturers of fake and inferior thick walled seamless steel pipes, rolling grooves often exceeds the standard.
3. The surface of fake and inferior thick walled seamless steel pipes is prone to scabbing. There are two reasons: ① The material of fake and inferior thick walled seamless steel pipes is uneven and there are many impurities. ② The guide equipment of fake and inferior material manufacturers is simple and easy to stick steel, and these impurities can easily cause scars when they bite into the rolling rolls.
4. The surface of fake and inferior materials is prone to cracks because their billet is made of adobe, which has many pores. During the cooling process, the adobe undergoes cracks due to thermal stress, which can occur after rolling.
5. Square tube tells the story of fake and inferior thick walled seamless steel pipes that are prone to scratches. The reason is that the equipment of the fake and inferior material manufacturers is simple and easy to produce burrs, which can scratch the surface of thick walled seamless steel pipes. Deep scratches reduce the strength of thick walled seamless steel pipes.
6. The fake and inferior thick walled seamless steel pipe has no metallic luster and appears in a light red or pig iron like color. There are two reasons: ① its billet is adobe. ② The rolling temperature of fake and inferior materials is not standard, and their steel temperature is visually measured, which makes it impossible to roll according to the specified austenite area, and the performance of thick walled seamless steel pipes naturally cannot meet the standard.
7. Seamless square tube tells the story of fake thick walled seamless steel pipes with thin and low transverse bars, often resulting in underfilling. The reason is that the manufacturer, in order to achieve a large negative tolerance, has a large reduction in the first few passes of the finished product, a small iron shape, and underfilling of the hole shape.
8. The cross-sectional shape of fake and inferior thick walled seamless steel pipes is elliptical, because the manufacturer, in order to save materials, has reduced the strength of the first two passes of the finished roll by a large amount, and this type of steel pipe does not meet the standards for external dimensions.
9. The manufacturer of special-shaped pipes tells us that the composition of high-quality thick walled seamless steel pipes is uniform, the tonnage of the cold shear machine is high, and the end face of the cutting head is smooth and neat. However, due to the poor material quality of fake and inferior materials, the end face of the cutting head often has the phenomenon of falling flesh, which is uneven and has no metallic luster. Moreover, due to the limited cutting of fake and inferior material manufacturers' products, large ears may appear at the head and tail.
10. The fake and inferior thick wall seamless steel pipes contain many impurities, the density of the steel is too small, and the size is out of tolerance seriously, so they can be weighed and checked without Vernier scale. For example, for threaded steel 20, the national standard specifies a maximum negative tolerance of 5%. When the length is 9M, its theoretical weight for a single piece is 120 kilograms. Its minimum weight should be 120 X (l-5%)=114 kilograms. If the actual weight of a single piece measured is smaller than 114 kilograms, it is a fake and inferior thick walled seamless steel pipe because its negative tolerance exceeds 5%. Generally speaking, the whole phase weighing effect will be better, mainly considering the cumulative error and Probability theory.
