Views: 0 Author: Site Editor Publish Time: 2021-04-16 Origin: Site
The development of steel pipe production technology began with the rise of the bicycle manufacturing industry, the development of petroleum in the early 19th century, the manufacture of ships, boilers, and aircraft during the two world wars, the manufacture of thermal power boilers after the two world wars, the development of the chemical industry, and the development of petroleum The drilling, production and transportation of natural gas have strongly promoted the development of the steel pipe industry in terms of variety, output and quality.
While steel pipes are developing rapidly, some fake and inferior steel pipe products have appeared one after another on the market. So how to accurately and accurately identify the quality of steel pipes?
1. Fake and inferior steel pipes often have pitting on the surface.
pitted surface is the irregularity of the surface of the steel due to the serious wear of the rolling groove. As the counterfeit and inferior steel pipe manufacturers are pursuing profits, the production of groove rolling often exceeds the standard.
2. The cross-section of the counterfeit steel pipe is elliptical. The reason is that in order to save material, the reduction of the first two passes of the finished roll is too large. The strength of this kind of screw steel is greatly reduced, and it does not meet the standard of the shape of the screw steel. .
3. The composition of good steel is uniform, the tonnage of the cold shear is high, and the end face of the cutting head is smooth and tidy. However, due to the poor quality of the fake material, the end face of the cutting head often has meat loss, that is, it is uneven and has no metallic luster. Moreover, because the products of the counterfeit and inferior material manufacturers have fewer cuts, big ears will appear at the head and tail.
4. The inner diameter size of the fake and inferior steel pipe fluctuates greatly, and the reason is: l, the steel temperature is unstable and there is a negative and positive side. 2. The composition of steel is not uniform. 3. Due to the simple equipment and low foundation strength, the rolling mill bounces greatly. There will be large changes in the same week, and the uneven force of such steel bars is easy to break.
5. Fake and inferior steel pipes are easy to scratch, because the equipment of the manufacturers of fake and inferior steel pipes is simple and easy to produce burrs and scratch the surface of steel. Deep scratches reduce the strength of steel.
6. Fake and inferior steel pipes are prone to scars on the surface.
7.There are two reasons:
(1) The material of fake and inferior steel pipe is uneven and there are many impurities.
(2) The guidance and guarding equipment of the fake and inferior material manufacturers is simple and easy to stick to the steel. These impurities will easily cause scars after biting the roll.
8. The trademarks and printing of steel pipes are relatively standardized.
9. The longitudinal ribs of counterfeit and inferior steel rebar are often wavy.