How to identify inferior stainless steel welded pipes?

1. Stainless steel welded folded tube
Fake and inferior welded stainless steel pipes are easy to fold, and folding is a variety of folded lines formed on the surface of stainless steel pipes. Such defects usually run through the longitudinal direction of the entire product. The reason for the folding is that the counterfeit and shoddy manufacturers are too efficient and the pressure is too large, resulting in the formation of ears in the tube, which will form folds during the next rolling. The folded product will crack after bending, and the strength of the stainless steel tube will be significantly reduced. The appearance of the fake welded stainless steel pipe will be pitted. The stainless steel surface is uneven as the grooves wear out.
2. Stainless steel welded pipe scar
There are two main reasons for the surface of stainless steel pipes to be easily scratched. First, the inferior stainless steel welded pipe is not uniform in material, and there are many impurities. Second, the stainless steel pipe manufacturers have poor equipment and are easy to stick to steel. After these impurities are bitten into the roll, it is easy to form scars.
3. Cracks of stainless steel welded pipes
The surface of the fake stainless steel welded pipe is also prone to cracks, because the blank is adobe, and there are many pores in the adobe. During cooling, cracks occur due to thermal stress, and cracks occur after rolling.
4. Stainless steel welded pipe surface
The surface of the inferior stainless steel welded pipe has no metallic luster, and will appear light red or a color similar to pig iron. There are two reasons for the formation. One is blank is adobe. Second, the rolling temperature of counterfeit and inferior pipes is not standard, and the temperature of steel is visually measured. Therefore, the rolling of stainless steel pipes cannot meet the specified austenite zone requirements.
The fake stainless steel welded steel pipe is also easy to be scratched, because the production equipment of the fake stainless steel welded steel pipe manufacturer is simple and rough, and it is easy to form burrs. The surface of the steel is scratched, and the strength of the stainless steel pipe will be weakened by deep scratches.
The transverse ribs of stainless steel welded pipes of fake and inferior welding are thin and low, which often leads to the phenomenon of unsatisfactory filling. Because the manufacturer is to achieve a large negative tolerance, the first few passes of the finished product have too much reduction, the iron shape is too small, and the hole shape is also filled with dissatisfaction.
The section of the forged welded stainless steel tube is oval, because the manufacturer has a large pressure drop in the first two passes of the finished roll in order to save material.
5. Specifications and dimensions of stainless steel welded pipes
Negative tolerances for poor quality stainless steel welded pipe are often over spec. Inferior stainless steel pipes contain a lot of impurities, the material density of stainless steel pipes is low, and the size is too poor. Therefore, if there is no vernier caliper, it can be checked by weighing.
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