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How to distinguish the fake of steel pipe?
Apr 26, 2018

How to distinguish the fake of steel pipe?

Steel pipe is closely related to human life and production activities. The production technology of steel tube industry not only develops rapidly, but also brings forth new products. Steel pipe production occupies an irreplaceable position in the steel industry. The development of steel pipe production technology began with the rise of bicycle manufacturing.

Steel pipes are not only used for conveying fluids and powdery solids, exchanging heat energy, making mechanical parts and containers, but also a kind of economic steel. It can reduce the weight, save 20 ~ 40% of the metal, and realize the mechanized construction of factory. Using steel pipe to make highway bridge not only can save steel, simplify construction, but also greatly reduce the area of coating protection layer, save investment and maintenance cost. Therefore, no other type of steel can completely replace the steel tube, but the steel pipe can replace some sections and bars. The steel pipe has a great relationship with the improvement of the national economy and the quality of human life. From People's Daily appliances, furniture, water supply and drainage, gas supply, ventilation and heating facilities to various kinds of agricultural machinery equipment manufacturing, the development of underground resources, defense and aerospace used guns, bullets, missiles, rocket is inseparable from the steel tube, etc.

1. Fake and inferior steel pipes are easy to fold. Folding is a kind of broken line formed on the surface of the steel tube, which often runs through the vertical of the whole product. Causes of fold is due to the pursuit of the false and inferior, high efficiency, large reduction, handle, when the next rolling produce folding, folding products will be cracking after bending, strength of steel.

2. The appearance of the fake steel tube often has a surface. The surface is caused by the uneven surface of the steel surface due to the wear of the groove. Because the manufacturer of fake and inferior steel pipe should pursue profit, often appear the groove rolling is exceeding standard.

3. The surface of fake steel pipe can easily produce scar. There are two reasons for this :(1). Fake and inferior steel pipe material is not uniform, impurity is much. (2). Fake and inferior material manufacturer guide sanitation equipment is simple, easy to stick steel, these impurities bite a person roll after easy to produce scar.

4. And inferior material surface cracks easily, because its billet is adobe, adobe air, adobe in the process of cooling due to the effect of thermal stress, cracks, after rolling there is crack.

5. Shoddy steel pipe is easy to scratch because of shoddy equipment, easy to produce burr, scratch steel surface. Deep scratches reduce the strength of steel.

6. The fake steel tube has no metallic luster, and it has a light red or similar color of pig iron, for two reasons. It is blank. 2. The temperature of fake and inferior material rolling is not standard, their steel temperature is through visual inspection, so that it cannot be rolled in the regulated austenite region, and the performance of the steel cannot meet the standard.

7. The horizontal bars of the fake steel pipe are thin and low, which often appear to be filled with dissatisfaction. The reason is that the manufacturers have a large negative tolerance, and the first few lines of the finished product have a large amount of pressure, and the iron type is small and the pore type is not satisfied.

8. And inferior steel tube cross-section oval, because the factory in order to save material, the quantity of the finished product roll before 2 slants big, the strength of rebar is greatly decreased, but also do not conform to the standard of rebar shape size.

9. Cold shearing machine of high quality steel composition is uniform, high tonnage, cutting head end face smooth and neat, and shoddy material because the material is poor, cutting head end face often have meat, or uneven, and no metallic luster. Besides, due to the lack of cutting head, the head and tail will have big ears.

10. There are many impurities in the material of fake and inferior steel pipe, the density of steel is small, and the size is very bad, so it can be checked by weighing it without vernier caliper. For rebar 20, for example, maximum minus tolerance specified in the national standard of 5%, scale of 9 m in the theory of single weight is 120 kg, it should be the smallest weight: 120 x (l - 5%) = 114 kg, 114 kg weigh out the weight of the single than small, is false and inferior steel, the reason is that it is negative tolerance more than 5%. In general, the overall proportionality effect will be better, taking into account the cumulative error and probability theory.

11. The internal diameter of the fake steel pipe is more volatile, the reason is. L, steel temperature instability has a Yin and Yang surface. 2. The composition of steel is not uniform. 3. Due to the poor equipment, the foundation strength is low and the rolling mill is large. There will be a large change in the same week, such reinforcement stress is not uniform and easy to rupture.

12. Quality control of the trademark and printing of the specification.

13. Three steel pipe diameter of more than 16 big threads, the space between the two trademarks is above the IM.

14. The longitudinal bars of steel bars are often wavy. 15. Due to the lack of driving, fake and inferior steel pipe manufacturers are packaged loosely. The sides are oval in shape.


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