Methods for identifying fake and inferior steel pipes
Steel pipe is made of steel ingot or solid tube blank perforated into wool tube, and then hot rolled, cold rolled or cold dialled. Compared with solid steel such as round steel, it has the same bending and torsional strength and is light in weight. It is a kind of economic section steel, which is widely used in the manufacture of structural parts and mechanical parts, such as oil drill pipe, automobile transmission shaft, bicycle frame and steel scaffolding used in construction.
Fake and inferior quality identification method
1. Fake and inferior steel pipes are easy to scratch, because the manufacturer of fake and inferior steel pipes has simple equipment, which is easy to produce burrs and scratch the steel surface. Deep scratching reduces the strength of steel.
2. Fake and inferior steel pipes have no metallic luster and are light red or similar to pig iron.
3. The transverse ribs of fake and inferior steel pipes are thin and low, and the phenomenon of filling is often dissatisfied. The reason is that in order to achieve large negative tolerance, the pressure of the first few passes of the finished products is too large, the iron shape is too small, and the hole shape is not satisfied.
4. The cross section of shoddy steel pipe is elliptical, the reason is that the manufacturer in order to save materials, the pressure of the first two lines of the finished roller is too large, the strength of this steel pipe will decrease, and it does not meet the standard of steel pipe size.
5. Good steel pipe composition is uniform, the tonnage of cold shear machine is high, the end face of the cutting head is smooth and neat, and shoddy steel pipe because of poor material, the end face of the cutting head often has the phenomenon of falling meat, that is, uneven, and no metallic luster. And because the fake and inferior manufacturer's products cut less head, head and tail will appear big ears.
6. Fake and inferior steel pipe material contains many impurities, the density of steel is small, and the size is out of tolerance, so in the absence of vernier calipers, it can be weighed and checked. In general, weighing, mainly considering the cumulative error and probability theory of this problem.
