The production steps of thick-walled steel pipes and the phenomenon of inferior steel pipes

Thick-walled steel pipes refer to steel pipes whose outer diameter to wall thickness ratio is less than 20 as thick-walled steel pipes. Mainly used as petroleum geological drilling pipes, cracking pipes for the petrochemical industry, boiler pipes, bearing pipes, and high-precision structural pipes for automobiles, tractors, etc.

The biggest difference between thick-walled steel pipes and thin-walled steel pipes lies in the thickness of the steel pipe wall. Generally speaking, thin-walled steel pipes are cold-drawn technology, thick-walled steel pipes and thick-walled steel pipes generally use hot-rolled technology, if it is distinguished by measurement units, then, it is generally believed that the wall thickness/diameter equal to 0.02 is the watershed between thick-walled steel pipes and thin-walled steel pipes, those with wall thickness/diameter less than 0.02 are thin-walled steel pipes, and those with larger diameters are thick-walled steel pipes. Wall steel pipes are mostly used on pipelines. And thick-walled steel pipes are mostly used as blanks for hollow parts. Used on pressure-bearing and important pipelines.

Thick-walled steel pipes are mainly used in water supply engineering, the petrochemical industry, the chemical industry, the electric power industry, agricultural irrigation, and urban construction. Used for liquid transportation: water supply and drainage. For gas transportation: gas, steam, liquefied petroleum gas. For structural purposes: as piling pipes, as bridges; pipes for wharves, roads, building structures, etc.

Phenomena of fake and inferior thick-walled steel pipes:
1. Shoddy thick-walled steel pipes are prone to folding.
2. The appearance of fake and inferior thick-walled steel pipes often has pockmarks.
3. The surface of fake and inferior thick-walled steel pipes is prone to scarring.
4. The surface of fake and inferior materials is prone to cracks.
5. Shoddy thick-walled steel pipes are easy to scratch.
6. Shoddy thick-walled steel pipes have no metallic luster and are light red or similar in color to pig iron.
7. The horizontal ribs of fake and inferior thick-walled steel pipes are thin and low, and they often appear to be full and dissatisfied.
8. The cross-section of fake and inferior thick-walled steel pipes is oval.
10. The material of fake and inferior thick-walled steel pipes contains many impurities, and the density of steel is relatively small.
11. The inner diameter of fake and inferior thick-walled steel pipes fluctuates greatly.
12. Tube trademarks and printing are more standardized.
13. For large threads with a steel pipe diameter of 16 or more, the distance between the two trademarks is more than 1M.
14. The longitudinal reinforcement of fake and inferior steel rebar is often wavy.
15. Manufacturers of fake and inferior thick-walled steel pipes do not have driving vehicles, so the packaging is loose. The sides are oval.

Production steps of thick-walled steel pipes:
1. The thick-walled steel pipe with stainless steel elbow variable wall thickness changes the wall thickness along the length of the pipe;
2. Process the cross-section of the square tube, and change the circular section into a square, ellipse, or polygon;
3. For square tubes with crimping and bottom sealing, increase the total strength of the tube end to crimp the outside or inside of the tube or seal the end of the square tube;
4. Stainless steel elbow variable-diameter square pipe refers to the reduced diameter of the pipe end or a certain part of the pipe;
5. The stainless steel elbow bends the square pipe, and the contact is more, that is, the straight pipe is changed into the bend pipe with different curvature radius, such as elbow, bend pipe, etc.;
6. Square tube with flange and round edge, the former refers to the end of the tube protruding to the inside or outside, and the latter refers to the square tube that forms a bulge or groove in the circumferential direction of the tube.