15 points to teach you to identify counterfeit thick-walled seamless pipe 1. Counterfeit thick-walled seamless steel pipe is prone to collapse. Folding is the formation of a variety of fold lines on the surface of thick-walled seamless steel tubes. Such defects often run through the entire product. The reason for the folding is due to the high efficiency of the shoddy manufacturers, the large amount of reduction, the generation of ears, and the folding of the folded products. The folded products will crack after bending, and the strength of the thick-walled seamless steel pipe will decrease greatly. .
2. Pseudo-inferior thick-walled seamless steel pipes often have pockmarked appearance. Mamian is a defect caused by the irregular wear and tear of the thick-walled seamless steel pipe due to the wear of the groove. Due to fake and thick thick-walled seamless steel pipe manufacturers to seek profits, rolling slot rolling is often the most excessive.
3. Pseudo-inferior thick-walled seamless steel pipe surface is prone to scarring. There are two reasons for this: 1. Pseudo-inferior thick-walled seamless steel pipes are not uniform in material and have many impurities. 2. The inferior guide manufacturers' equipment is simple and easy to stick to steel, and these impurities are easy to produce scars after being bitten by rollers.
4. The surface of the inferior material is prone to cracks because its blank is adobe and the porosity of the blank is large. The adobe is subjected to thermal stress during the cooling process and cracks are generated. After the rolling, cracks occur.
5. Pseudo-inferior thick-walled seamless steel pipe is easy to be scratched because the equipment of the inferior and inferior material manufacturers is simple and easy to produce burrs and scratch the surface of the thick-walled seamless steel pipe. Deep scratches reduce the strength of thick-walled seamless steel tubes.
6. Pseudo-inferior thick-walled seamless steel tubes have no metallic luster and are pale red or similar to the color of pig iron for two reasons. Its blanks are adobe. 2. The temperature of the shoddy material rolling is not standard. Their steel temperature is measured visually, so that the rolling cannot be carried out according to the prescribed austenitic region. The performance of thick-walled seamless steel tubes naturally cannot be achieved.
7. The cross-bars of the counterfeit and thick-walled seamless steel tubes are thin and low, and the phenomenon of insufficient filling often occurs. The reason is that the manufacturers have to achieve large negative tolerances, the amount of reduction in the first few passes of the finished products is too large, the iron type is too small, and the hole type is insufficient.
8. Pseudo-inferior thick-walled seamless steel tubes have elliptical cross-sections. The reason is that in order to save materials, the amount of reduction in the former two rolls of the finished rolls is too large. The strength of this rebar steel is greatly reduced, and it does not conform to the rebar size. The standard.
9. High-quality thick-walled seamless steel pipe has uniform composition, cold tongs have high tonnage, and the end surface of the cutting head is smooth and neat. However, due to poor material quality, the cut end face often has a phenomenon of losing meat, ie unevenness, and no metallic luster. . Moreover, due to the lack of cut-to-size products from manufacturers of inferior and inferior products, big ears will appear at the head and tail.
10. Pseudo-inferior thick-walled seamless steel pipe material contains many impurities, the density of the steel is small, and the size of the ultra-thin pipe is so bad that it can be weighed and verified without a vernier caliper. For example, for rebar 20, the national standard specifies a maximum negative tolerance of 5%. When the length is 9M, its single theoretical weight is 120 kg. Its minimum weight should be: 120 X (l-5%) = 114 kg. The actual weighing of a single root weighing less than 114 kilograms is a pseudo-inferior thick-walled seamless steel pipe because its negative tolerance exceeds 5%. In general, the phasing effect will be better, mainly considering cumulative error and probability theory.
11. The size of the inner diameter of counterfeit and thick-walled seamless steel tubes fluctuates greatly. The reason is that: l. The steel temperature is unstable and there are yin-yang surfaces. 2, the composition of steel is not uniform. 3, due to the simple equipment, low strength of the foundation, the mill bouncing. There will be a large change in the inner diameter within the same week, so that the steel reinforcement is not easy to produce fracture.
12. The trademarks and printing of high quality materials are more standard.
13. Three large-walled seamless steel tubes with a diameter of 16 or more, the spacing between the two trademarks are all above IM.
14. The longitudinal bars of counterfeit thick-walled seamless steel tubes are often wavy.
15. Pseudo-inferior thick-walled seamless steel pipe manufacturers have looser packing because they do not drive. The side is oval.
2. Pseudo-inferior thick-walled seamless steel pipes often have pockmarked appearance. Mamian is a defect caused by the irregular wear and tear of the thick-walled seamless steel pipe due to the wear of the groove. Due to fake and thick thick-walled seamless steel pipe manufacturers to seek profits, rolling slot rolling is often the most excessive.
3. Pseudo-inferior thick-walled seamless steel pipe surface is prone to scarring. There are two reasons for this: 1. Pseudo-inferior thick-walled seamless steel pipes are not uniform in material and have many impurities. 2. The inferior guide manufacturers' equipment is simple and easy to stick to steel, and these impurities are easy to produce scars after being bitten by rollers.
4. The surface of the inferior material is prone to cracks because its blank is adobe and the porosity of the blank is large. The adobe is subjected to thermal stress during the cooling process and cracks are generated. After the rolling, cracks occur.
5. Pseudo-inferior thick-walled seamless steel pipe is easy to be scratched because the equipment of the inferior and inferior material manufacturers is simple and easy to produce burrs and scratch the surface of the thick-walled seamless steel pipe. Deep scratches reduce the strength of thick-walled seamless steel tubes.
6. Pseudo-inferior thick-walled seamless steel tubes have no metallic luster and are pale red or similar to the color of pig iron for two reasons. Its blanks are adobe. 2. The temperature of the shoddy material rolling is not standard. Their steel temperature is measured visually, so that the rolling cannot be carried out according to the prescribed austenitic region. The performance of thick-walled seamless steel tubes naturally cannot be achieved.
7. The cross-bars of the counterfeit and thick-walled seamless steel tubes are thin and low, and the phenomenon of insufficient filling often occurs. The reason is that the manufacturers have to achieve large negative tolerances, the amount of reduction in the first few passes of the finished products is too large, the iron type is too small, and the hole type is insufficient.
8. Pseudo-inferior thick-walled seamless steel tubes have elliptical cross-sections. The reason is that in order to save materials, the amount of reduction in the former two rolls of the finished rolls is too large. The strength of this rebar steel is greatly reduced, and it does not conform to the rebar size. The standard.
9. High-quality thick-walled seamless steel pipe has uniform composition, cold tongs have high tonnage, and the end surface of the cutting head is smooth and neat. However, due to poor material quality, the cut end face often has a phenomenon of losing meat, ie unevenness, and no metallic luster. . Moreover, due to the lack of cut-to-size products from manufacturers of inferior and inferior products, big ears will appear at the head and tail.
10. Pseudo-inferior thick-walled seamless steel pipe material contains many impurities, the density of the steel is small, and the size of the ultra-thin pipe is so bad that it can be weighed and verified without a vernier caliper. For example, for rebar 20, the national standard specifies a maximum negative tolerance of 5%. When the length is 9M, its single theoretical weight is 120 kg. Its minimum weight should be: 120 X (l-5%) = 114 kg. The actual weighing of a single root weighing less than 114 kilograms is a pseudo-inferior thick-walled seamless steel pipe because its negative tolerance exceeds 5%. In general, the phasing effect will be better, mainly considering cumulative error and probability theory.
11. The size of the inner diameter of counterfeit and thick-walled seamless steel tubes fluctuates greatly. The reason is that: l. The steel temperature is unstable and there are yin-yang surfaces. 2, the composition of steel is not uniform. 3, due to the simple equipment, low strength of the foundation, the mill bouncing. There will be a large change in the inner diameter within the same week, so that the steel reinforcement is not easy to produce fracture.
12. The trademarks and printing of high quality materials are more standard.
13. Three large-walled seamless steel tubes with a diameter of 16 or more, the spacing between the two trademarks are all above IM.
14. The longitudinal bars of counterfeit thick-walled seamless steel tubes are often wavy.
15. Pseudo-inferior thick-walled seamless steel pipe manufacturers have looser packing because they do not drive. The side is oval.