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How To Identify Fake And Inferior High Pressure Boiler Tubes

Changsha China
Categories: Manufacturing Engineering / China Tags:
boiler tubes
sseamless steel pipe

High pressure boiler tube is a kind of boiler tube, which belongs to the category of seamless steel pipe. The manufacturing method is the same as that of seamless pipes, but there are strict requirements on the steel grades used to manufacture steel pipes.High-pressure boiler tubes are often used in high temperature and high pressure conditions, and the tubes will be oxidized and corroded under the action of high-temperature flue gas and water vapor. The steel pipe is required to have high lasting strength, high oxidation corrosion resistance, and good microstructure stability. High-pressure boiler tubes are mainly used to manufacture superheater tubes, reheater tubes, gas guide tubes, main steam tubes, etc. of high-pressure and ultra-high-pressure boilers.

1. Fake and inferior high-pressure boiler tubes are prone to folding. Folds are various fold lines formed on the surface of high-pressure boiler tubes, and this defect often runs through the longitudinal direction of the entire product. The reason for the folding is that the counterfeit and inferior manufacturers pursue high efficiency, and the reduction amount is too large, resulting in ears, and folding occurs during the next rolling. The folded product will crack after bending, and the strength of the high-pressure boiler tube will be greatly reduced.

2. The appearance of fake and inferior high-pressure boiler tubes often has a pockmarked surface. The pockmarked surface is the irregular uneven surface of the high-pressure boiler tube surface due to the serious wear of the rolling groove. Due to the pursuit of profit by manufacturers of fake and shoddy high-pressure boiler tubes, groove rolling often exceeds the standard.

3. Fake and inferior high-pressure boiler tubes are prone to scarring on the surface. There are two reasons: 1) The material of the fake and inferior high-pressure boiler tubes is uneven, and there are many impurities; 2) The guide and guard equipment of the fake and inferior material manufacturers are simple and easy to stick to the steel, and these impurities are prone to scarring after biting the roll.

4. The surface of the fake and inferior material is prone to cracks, because its blank is adobe, and the adobe has many pores, and the adobe is subjected to thermal stress during the cooling process, resulting in cracks. After rolling, there are cracks.

5. The fake and inferior high-pressure boiler tubes are easy to be scratched, because the fake and inferior materials manufacturers have simple equipment, which is easy to produce burrs and scratch the surface of the high-pressure boiler tubes. Deep scratches reduce the strength of high pressure boiler tubes.

6. The fake and inferior high-pressure boiler tube has no metallic luster and is light red or similar to pig iron for two reasons: 1) Its blank is adobe. 2) The rolling temperature of fake and inferior materials is not standard, and their steel temperature is measured visually, so that it cannot be rolled according to the specified austenite area, and the performance of high-pressure boiler tubes will naturally fail to meet the standard.

7. The transverse ribs of the fake and inferior high-pressure boiler tubes are thin and low, and the phenomenon of unsatisfactory filling often occurs. The reason is that in order to achieve a large negative tolerance, the reduction amount of the first few passes of the finished product is too large, the iron shape is too small, and the hole shape is not filled enough.

8. The cross-section of the fake and inferior high-pressure boiler tubes is oval. The reason is that in order to save materials, the reduction amount of the first two passes of the finished roller is too large, and the strength of this kind of rebar is greatly reduced.And it also does not meet the standard of rebar dimensions.

9. The composition of high-quality high-pressure boiler tubes is uniform, the tonnage of the cold shearing machine is high, and the end face of the cutting head is smooth and neat, while the end face of the cutting head is often uneven and has no metallic luster due to the poor material of the fake and inferior material.

10. The material of the fake and inferior high-pressure boiler tube contains a lot of impurities, the density of the steel is too small, and the size is out of tolerance, so it can be weighed and checked without a vernier caliperFor example, for rebar 20, the national standard stipulates that the maximum negative tolerance is 5%. When the fixed length is 9M, its single theoretical weight is 120 kg, and its minimum weight should be: 120 × (1-5%) = 114 kg , the actual weight of a single piece is less than 114 kg, it is a fake and inferior high-pressure boiler tube, because its negative tolerance exceeds 5%.

11. The inner diameter of the fake and inferior high-pressure boiler tubes fluctuates greatly because of: 1) The steel temperature is unstable and there are yin and yang surfaces; 2) The composition of the steel is uneven; 3) Due to the simple equipment, low foundation strength, and large bouncing of the rolling mill. There will be a large change in the inner diameter within the same week, and the uneven stress of such a steel bar is prone to fracture.

12. The trademark and printing of high-quality materials are relatively standardized. The longitudinal bars of the fake and inferior high-pressure boiler tubes are often wavy