Counterfeit and inferior the seamless pipe appears from time to time in the market, bringing many safety hazards and economic losses to users. The following are some ways to identify counterfeit and inferior seamless pipes to help you avoid being deceived when purchasing.

Appearance inspection

1. Pockmarking

The surface of counterfeit and inferior seamless pipes often has pitting, that is, irregular bumps and unevenness. This is caused by severe wear of the rolling groove. In order to pursue profits, counterfeit and inferior seamless pipe factories often let the rolling groove exceed the standard, thus affecting the surface quality of the steel pipe.

2. Scarring problem

Scarring is easy to occur on the surface of this type of seamless pipe. There are two main reasons: one is that the material is uneven and there are many impurities; the other is that the guide equipment of the counterfeit factory is simple and easy to stick to steel. After these impurities bite into the roller, they will form scars on the surface of the steel pipe.

3. Folding defect

Folding is a variety of fold lines formed on the surface of the seamless pipe. This defect often runs through the entire longitudinal direction of the product. In order to pursue high efficiency, the counterfeit factory presses down too much, resulting in ears, and folding is formed during the next rolling. Folded products are prone to cracking after bending, and the strength of thick-walled seamless pipes will also drop significantly.

4. Scratching problem

The surface of counterfeit and inferior seamless pipes is prone to scratches. This is because the equipment of the counterfeit factory is simple and easy to produce burrs, which scratch the surface of the steel pipe. Deep scratches will reduce the strength of the seamless pipe.

5. Crack phenomenon

This type of seamless pipe is prone to cracks. The reason is that its blank is usually adobe, which has many pores. During the cooling process, due to the effect of thermal stress, the blank will produce cracks, and after rolling, the cracks will become cracks.

6. Lack of metallic luster

Fake and inferior seamless pipes usually have no metallic luster and are light red or similar to pig iron. There are two main reasons: one is that the blank is adobe; the other is that the rolling temperature of the counterfeit factory is not standard, and the steel temperature is determined by visual inspection. It cannot be rolled according to the specified austenite area, resulting in the performance of the seamless pipe not meeting the standard.

Size and shape inspection

1. Cross-sectional shape

The cross-section of counterfeit and shoddy seamless pipes is often elliptical. This is because the counterfeit factory, in order to save materials, presses down the first two passes of the finished product roll too much. The strength of this steel pipe will drop significantly and does not meet the standard of external dimensions.

2. Cross-rib problem

The cross-rib is usually thin and low, and often appears to be incomplete. This is because in order to achieve a large negative tolerance, the counterfeit factory presses down the first few passes of the finished product too much, the iron type is too small, and the hole type is not fully filled.

3. Inner diameter size fluctuation

The inner diameter size of counterfeit and shoddy seamless pipes fluctuates greatly. There are three main reasons: first, the steel temperature is unstable and there are yin and yang sides; second, the steel composition is uneven; third, the equipment is simple, the foundation strength is low, and the rolling mill bounces large. This will cause a large change in the inner diameter within the same week, making the steel pipe unevenly stressed and prone to breakage.

Material and processing inspection

1. Material problem

The material of counterfeit and shoddy seamless pipes contains many impurities, the density of steel is too small, and the size exceeds the tolerance seriously. In the absence of a vernier caliper, it can be judged by weighing and checking.

2. Cut end face

The cut end face of high-quality seamless pipes is smooth and neat, while the cut end face of fake and inferior seamless pipes often has meat loss due to poor material, that is, uneven and without metallic luster. In addition, due to the small number of cut ends of fake and inferior factory products, large ears will appear at the head and tail.