There are a total of 15 identification methods for fake and inferior square tubes. 1. Fake and inferior square tubes are prone to folding. Folding is a variety of creases formed on the surface of square tubes, which often run through the longitudinal direction of the entire product. The reason for folding is due to the pursuit of high efficiency by fake and inferior manufacturers, which results 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 the steel. 2. The appearance of fake and inferior square tubes 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 steel surface. Due to the pursuit of profit by fake and inferior square tube manufacturers, rolling grooves often exceeds the standard. 3. The surface of fake and inferior square tubes is prone to scabbing. There are two reasons: (1). The material of fake and inferior square tubes 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. Fake and inferior thick walled pipes are prone to scratches due to the simple equipment of the manufacturer of fake and inferior square pipes, which can easily produce burrs and scratch the surface of the steel. Deep scratches reduce the strength of steel. 6. The fake thick walled seamless square tube has no metallic luster and appears in a light red or similar color to pig iron. There are two reasons for this: 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 the steel cannot meet the standard. 7. The horizontal bars of fake and inferior square pipes are thin and low, often resulting in insufficient filling. The reason is that the manufacturer, in order to achieve a large negative tolerance, has a larger reduction in the first few layers of the finished product, a smaller iron shape, and insufficient filling of the hole shape. 8. The cross-sectional shape of the fake square tube 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 threaded steel does not meet the standards for the external dimensions of the threaded steel. 9. The composition of high-quality steel 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 square tube material contains a lot of impurities, the density of the steel is relatively small, and the size is severely out of tolerance. Therefore, without a vernier caliper, it can be weighed and verified. For example, for threaded steel 20, the national standard specifies a maximum negative tolerance of 5%. When the length is 9M, the theoretical weight of 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 considered a counterfeit steel because its negative tolerance exceeds 5%. Generally speaking, the whole phase weighing effect will be better, mainly considering the cumulative error and probability theory. 11. The inner diameter size of counterfeit square tubes fluctuates greatly due to:; l. The steel temperature is unstable and there are yin and yang sides. 2. The composition of steel is uneven. 3. Due to the simple equipment, low foundation strength, and high bounce of the rolling mill. There may be significant changes within the same week, which can cause uneven stress on the steel bars and lead to fracture. The trademark and printing of high-quality pipes are relatively standardized. 13. For large threads with a diameter of 16 or more in a square tube, the spacing between the two trademarks is above IM. 14. The longitudinal bars of forged and inferior steel bars are often wavy. 15. The manufacturer of fake and inferior square tubes has loose packaging due to not driving. The side is elliptical in shape.