Identification method of fake thick wall seamless steel pipe

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Identification method of fake thick wall seamless steel pipe

Identification method of fake thick wall seamless steel pipe

1. The fake thick wall seamless steel pipe is easy to fold.

Folding is a kind of broken line formed on the surface of thick wall seamless steel pipe, which often runs through the longitudinal direction of the whole product. The reason for folding is that the fake and inferior manufacturers pursue high efficiency, the reduction is too large, the ears are produced, and the folding occurs in the next rolling, the folded products will crack after bending, and the strength of the thick wall seamless steel pipe will be greatly reduced.

2. The appearance of fake thick wall seamless steel pipe often has pockmarks.

Pitted surface is a kind of irregular and uneven defect on the surface of thick wall seamless steel pipe caused by the serious wear of rolling groove. Because the manufacturers of fake thick wall seamless steel pipe want to pursue profit, the rolling groove often exceeds the standard.

3. The surface of the fake thick wall seamless steel pipe is prone to scab.

There are two reasons: 1. The material of the fake thick wall seamless steel pipe is uneven and there are many impurities. 2. The guide and guard equipment of fake and inferior material manufacturers is simple and easy to stick steel, and these impurities are easy to produce scars after rolling.

4. The surface of fake and inferior materials is easy to crack,

The reason is that the billet is adobe, there are many air holes in the adobe, and the adobe is cracked due to the effect of thermal stress in the process of cooling, and there will be cracks after rolling.

5. The fake thick wall seamless steel pipe is easy to be scratched,

The reason is that the equipment of fake and inferior material manufacturers is simple and crude, which is easy to produce burr and scratch the surface of thick wall seamless steel pipe. Deep scratch reduces the strength of thick wall seamless steel pipe.

6. The fake thick wall seamless steel pipe has no metallic luster and is light red or similar to pig iron. There are two reasons. 1. Its blank is adobe. 2. The rolling temperature of the fake and inferior materials is not standard, and their steel temperature is measured visually, so that they cannot be rolled according to the specified austenite area, and the performance of the thick wall seamless steel pipe naturally cannot reach the standard.

7. The transverse reinforcement of the fake thick wall seamless steel pipe is thin and low, which often leads to insufficient filling,

The reason is that in order to achieve a large negative tolerance, the reduction of the first few passes of the finished product is too large, the iron mold is too small, and the hole mold is not fully filled.

8. The cross section of the fake thick wall seamless steel pipe is elliptical,

The reason is that in order to save materials, the reduction of the front two passes of the finished roll is too large, the strength of this steel pipe is greatly reduced, and it does not meet the standard of the overall dimension.

9. The composition of high-quality thick wall seamless steel pipe is uniform, the tonnage of cold shear is high, and the end face of cutting head is smooth and neat. However, due to the poor material of fake and inferior materials, the end face of cutting head often has the phenomenon of meat falling, that is, uneven, and no metallic luster.

10. There are many impurities in the material of the fake thick wall seamless steel pipe, the density of the steel is too small, and the size is seriously out of tolerance, so it can be weighed and checked without the vernier caliper. For example, for the screw steel 20, the national standard specifies that the maximum negative tolerance is 5%. When the scale is 9m, the theoretical weight of its single piece is 120kg, and its minimum weight should be: 120x (L-5%) = 114kg. The actual weight of the single piece weighed out is smaller than 114kg, which is a fake thick wall seamless steel pipe, because its negative tolerance is more than 5%. Generally speaking, the whole phase weighing effect will be better, mainly considering the problem of cumulative error and probability theory.

2019-12-04T11:26:20+08:00 December 4th, 2019|