Straight seam welded pipe production process is simple, high production efficiency, low cost, faster development. The strength of spiral welded pipe is generally higher than that of straight seam welded pipe, and it can produce welded pipe with larger pipe diameter from narrower billet, and it can also produce welded pipe with different pipe diameter from the same width of billet. However, compared with the same length of straight seam pipe, the length of welded seam increases by 30-100%, and the production speed is lower.

In recent years, with the continuous upgrading of the welding process of large diameter spiral steel pipe (SSAW), its processing quality and process performance will be significantly improved. As a result, the quality of the plant will also differ in grade. Among other things, there will be a very big gap in its quality after the increasing variety of such pipes sold on the market. So, what exactly determines it?

Spiral steel pipe is a strip of steel coil as raw material, often temperature extrusion city pressure, according to the spiral shape of the bending molding, automatic double-wire double-sided submerged arc welding process for the inner seam and outer seam welded spiral seam steel pipe. Raw materials, namely strip coil, welding wire, flux.

Spiral steel pipe irrigation system can be categorized into mobile, semi-fixed and fixed according to the working mode.

There are many kinds of quality inspection methods for LSAW pipe, among which the physical method is also the most commonly used inspection method, and the physical inspection is the method of using some physical phenomena for determination or inspection. Material or welded pipe internal defects in the inspection, are generally used non-destructive flaw detection methods. The current non-destructive testing has a magnetic flaw detection, ultrasonic flaw detection, ray detection, infiltration detection.

Submerged arc welding welding zone prone to defects such as porosity, hot cracks, and biting edge. Gas bubbles. Bubbles mostly occur in the center of the weld channel, the main reason is that hydrogen is still in the form of bubbles hidden inside the weld metal, so the measures to eliminate this defect is that first of all, you must remove the wire and weld rust, oil, water and moisture and other substances, and second is that you must dry the flux very well to remove moisture. In addition, increase the current, reduce the welding speed, slow down the solidification of the molten metal is also very effective.

1. During the molding process, the steel plate is uniformly deformed, the residual stress is small, and there is no scratch on the surface. The processed spiral steel pipe has more flexibility in the range of diameter and wall thickness, especially in the production of high steel grade thick-walled pipe, especially small and medium diameter thick-walled pipe, it has the advantages that other processes can not be compared to meet the needs of users.

Domestic manufacturers of LSAW pipes usually improve their properties by adding alloys to the material. After cold drawing, stress annealing must be carried out to eliminate the residual stress of the material to prevent the fracture of LSAW pipes.

In general, the diameter of the spiral steel pipe tube can be divided into outer diameter, inner diameter, nominal diameter. Pipe material for the spiral steel pipe pipe outside diameter with the letter D to indicate, followed by additional outer diameter of the size and wall thickness, for example, the outer diameter of 108 seamless steel pipe, wall thickness of 5MM, with D108 * 5, said the plastic pipe is also expressed in terms of the outer diameter, such as De63, others, such as reinforced concrete pipe, cast iron pipe, galvanized pipe and so on, using DN, in the design drawings are generally used to indicate the nominal diameter, nominal diameter is In order to design, manufacture and maintenance of the convenience of artificially stipulated a standard, but also more nominal diameter, is the name of the specifications of the pipe (or fittings).

In recent years, with the continuous upgrading of the welding process of large diameter spiral steel pipe (SSAW), its processing quality and process performance will be significantly improved. There will be a very big gap between the quality of such pipes sold on the market after the variety of such pipes is increasing. What can determine the quality of large diameter spiral steel pipe?