L245 high-frequency straight seam steel pipe commonly used in industrial projects

L245 straight seam steel pipe is a steel pipe with the weld parallel to the longitudinal direction of the steel pipe. It is usually divided into metric electric welded steel pipe, electric welded thin-walled pipe, transformer cooling oil pipe, etc. The production process of straight seam welded steel pipe is simple, the production efficiency is high, the cost is low, and the development is relatively fast. The strength of spiral welded steel pipe is generally higher than that of straight seam welded steel pipe. It can produce welded steel pipes with larger diameters with narrower billets, and welded steel pipes with different diameters can be produced with billets of the same width. However, compared with straight seam pipes of the same length, the weld length increases by 30~100%, and the production speed is lower.

Straight seam steel pipe in English (Straight seam steel pipe), general welded steel pipe: general welded steel pipe is used to transport low-pressure fluids. Steel pipes must undergo water pressure, bending, flattening, and other experiments, and have certain requirements for surface quality. The delivery length is usually 4-10m, and fixed-length (or multiple-length) delivery is often required. According to the specified wall thickness, welded steel pipes are divided into two types: ordinary steel pipes and thickened steel pipes. According to the form of the pipe ends, steel pipes are divided into two types: threaded and non-threaded.

Submerged arc welding process of L245 high-frequency straight seam steel pipe

1. Plate detection: After the steel plate used to manufacture large-diameter submerged arc welded straight seam steel pipe enters the production line, the whole plate is first subjected to ultrasonic inspection;

2. Edge milling: The two edges of the steel plate are double-sided milled by the edge milling machine to achieve the required plate width, plate edge parallelism, and groove shape;

3. Pre-bending edge: The plate edge is pre-bent by the pre-bending machine so that the plate edge has the required curvature;

4. Forming: On the JCO forming machine, the first half of the pre-bent steel plate is pressed into a "J" shape through multiple-step punching, and then the other half of the steel plate is bent in the same way to form a "C" shape, and finally an open "O" shape is formed

5. Pre-welding: The formed straight seam welded steel pipe is seamed and continuously welded by gas-shielded welding (MAG);

6. Internal welding: The inner side of the straight seam steel pipe is welded by longitudinal multi-wire submerged arc welding (up to four wires);

7. External welding: longitudinal multi-wire submerged arc welding is used to weld on the outside of the straight seam submerged arc welded steel pipe;

8. Ultrasonic inspection I: 100% inspection of the internal and external welds of the straight seam welded steel pipe and the parent materials on both sides of the weld;

9. X-ray inspection I: 100% X-ray industrial television inspection of the internal and external welds, using an image processing system to ensure the sensitivity of flaw detection;

10. Diameter expansion: The diameter of the submerged arc welded straight seam steel pipe is expanded over the entire length to improve the dimensional accuracy of the steel pipe and improve the distribution of stress inside the steel pipe;

11. Water pressure test: The expanded steel pipes are inspected one by one on a water pressure testing machine to ensure that the steel pipes meet the test pressure required by the standard. The machine has automatic recording and storage functions;

12. Chamfering: The steel pipes that have passed the inspection are processed at the pipe end to achieve the required pipe end groove size;

13. Ultrasonic inspection II: Ultrasonic inspection is performed again on each pipe to check for possible defects in the straight seam welded steel pipe after diameter expansion and water pressure;

14. X-ray inspection II: X-ray industrial television inspection and pipe end weld filming are carried out on the steel pipe after expansion and water pressure test;

15. Magnetic particle inspection of pipe end: This inspection is carried out to find defects at the pipe end;

16. Anti-corrosion and coating: After passing the inspection, the qualified steel pipe is anti-corrosion and coated according to the user's requirements.

Uses of L245 high-frequency straight seam steel pipe

Straight seam steel pipe is mainly used in tap water engineering, the petrochemical industry, the chemical industry, the power industry, agricultural irrigation, and urban construction.

For liquid transportation: water supply and drainage.

For gas transportation: coal gas, steam, liquefied petroleum gas.

For structural use: as piling pipe, as a bridge; pipes for docks, roads, building structures, etc.