Why use lubricants when making LSAW steel pipes?

Why use lubricants when making LSAW steel pipes?

In the production process of LSAW steel pipes, we need to use another product for cooperation, that is glass lubricant. Before using glass lubricants, they were all produced with graphite, because there was no product of this technology on the market at that time, so graphite could only be used as lubricant, but the heat insulation effect of graphite is very poor, and the traditional The thermal efficiency is very high. Therefore, manufacturers have been looking for an alternative to graphite products, and that is glass lubricants, which are designed to last for a long period of time. Therefore, it can play a role of heat preservation, which can prolong the use time of the equipment.

The principle of LSAW steel pipe:

The principle of LSAW steel pipe is to isolate the moisture corrosive medium in the air through the coating film to protect the surface of the metal material from corrosion. Common surface coating methods include hand coating, air spray, electrostatic spray and high pressure spray.

Hand Spray: This method is simple and easy to use and can be used to construct a variety of paints. Manual spraying involves thinning the paint to the proper consistency and applying it in layers with a brush. The quality of spraying depends on the skill level of the operator. The impact is greater, and it is difficult to form a uniform film. However, the efficiency is low. Hand-sprayed materials should be applied in a criss-cross pattern from top to bottom and left to right, and the thickness should be evenly distributed without any brush loss and hanging flow.

Air spraying: compressed air used for air spraying to generate high-speed airflow, paint storage tank mixing sprayer, atomize and spray liquid paint on the surface of objects, use air pressure spray gun, spray air film thick and smooth surface, high efficiency, but It is usually necessary to coat the film several times to achieve the desired thickness, to increase the thickness of the film spray, it can also be sprayed with heat, and the thermal spray coating is heated to about 70%.

The tightness of LSAW steel pipe:

The sealing performance of LSAW steel pipe is very poor. Flat joint control concrete pipes rely only on the rings of the concrete structure to seal the connection. Difficult to ensure no leaks during construction. Also, rigid pipe in concrete piping systems operates slightly differently. (For example, uneven settlement of soil quality) will directly damage the joints, corroded industrial wastewater, metal and underground concrete pipes are not as corrosion-resistant as plastic pipes. The natural ecological environment has a great influence on the corrosion of outdoor activities in some areas.

Cold knowledge about LSAW steel pipe

1. Plate inspection: After the steel plate used to manufacture large-diameter submerged arc welded LSAW steel pipes enters the production line, the entire plate is first inspected by ultrasonic, and production can begin after confirmation.
2. Milling: According to the pipe diameter requirements, use a milling machine to mill the two edges of the steel plate on both sides to achieve the required plate width, plate edge parallelism and bevel shape.
3. Pre-bending: Use a pre-bending machine to pre-bend the edge of the board so that the curvature of the edge meets the requirements.

4. Forming: On the JCO forming machine, the first half of the pre-bent steel plate is pressed into a "J" shape by multiple steps and punches, and then the other half of the steel plate is bent and pressed into a "C" shape to form an "O" shape opening .
5. Pre-welding: make the formed LSAW welded steel pipe seam and use gas shielded welding (MAG) for continuous welding; internal welding: use longitudinal multi-wire submerged arc welding (up to four wires) on the inner side of the LSAW steel pipe welding.
6. External welding: Longitudinal multi-wire submerged arc welding is used to weld the outer side of the longitudinal submerged arc welded steel pipe; ultrasonic inspection: 100% inspection of the inner and outer welds of the longitudinally welded steel pipe and the basic materials on both sides of the weld.

7. X-ray inspection: 100% X-ray industrial TV inspection of internal and external welds, using image processing system to ensure the sensitivity of flaw detection; diameter expansion: expanding the total length of submerged arc welded LSAW steel pipes to improve the dimensional accuracy of steel pipes , to change the distribution of internal stress in the steel pipe.
8. Hydraulic test: Check the expanded steel pipe on the hydraulic testing machine to ensure that the steel pipe meets the test pressure required by the standard.
9. Chamfering: Process the pipe end of the qualified steel pipe to make it reach the required pipe end groove size.

10. Ultrasonic inspection II: Ultrasonic inspection is performed again to check possible defects of longitudinally welded steel pipes after diameter enlargement and water pressure.
11. X-ray inspection Ⅱ: X-ray inspection of industrial television, film formation of weld seam of pipe end of steel pipe after stretching and hydraulic test.

12. Pipe end magnetic particle inspection: perform this inspection to find pipe end defects; anti-corrosion: carry out anti-corrosion treatment on qualified steel pipes according to user requirements.