Pre-bending and sizing are the main steps in the spiral tube forming process. The main purpose of pre-bending is to solve the rebound problem of the tube blank, because the size of the rebound directly affects the intrinsic quality of the steel tube; the main purpose of the sizing is to obtain a more accurate diameter of the tube, because the diameter control is the main quality index of the steel tube. one. A suitable match between pre-bending and sizing is required to obtain an ideal steel pipe blank.
The following is a brief discussion on the formation process and characteristics of submerged arc welding of galvanized spiral steel pipes with 630*3 ribs. The principle of submerged arc welding: Submerged arc welding is the use of arc thermal energy welding, and manual welding rod arc welding is different: the submerged arc welding of the welding wire is exposed, there is no coating, submerged arc welding is indeed pre-paved welding flux to be welded The submerged arc welding wire extends into the flux, and the arc is formed under the flux. The formation process of the submerged arc welding is such that the welding wire is in contact with the workpiece. After the start button is pressed, the welding wire and the workpiece are energized, and the welding wire is returned. Withdrawing, the arc ignites, the welding carriage advances, the welding wire is continuously conveyed downwards, the arc is maintained to burn under the flux layer, and the welding pool is formed below the arc. Around the arc, the flux melts to form a cavity. The cavity and the pool continue to advance, and the metal behind the pool solidifies to form a continuous weld. This process is performed under the flux, so we can’t see it with the naked eye. It can be seen with X-ray photography. Since the spiral steel pipe adopts the welding technology of submerged arc automatic welding, besides this kind of high production efficiency; the production auxiliary time is less, the time for changing the welding rod is saved; the welding conditions are clean and no spatter, and the cleaning time is saved; the quality of the welding seam is high. It also provides the necessary conditions for the delivery of the spiral welded pipe plant, so that the production time of the large spiral steel pipe is guaranteed, so it is still widely used.
1. The pressure-bearing fluid is mainly used for the X46 welded pipe as the tube blank, and is often spirally formed in temperature. It is used for welding with double-sided submerged arc welding and is mainly used for spiral seam welded steel pipe devices for pressure fluid transportation. The ability of the steel pipe to withstand pressure is strong and the welding performance is also very good. After a variety of rigorous scientific inspections and tests, the use situation is relatively safe and reliable. The solid diameter of the steel pipe is large, the transmission efficiency is also high, and it can effectively save the investment of laying pipelines. It is mainly used for pipelines that transport oil and natural gas.
2. General low-pressure fluid transport is mainly hot-rolled steel coiled tube blanks, often temperature spiral molding, using high-frequency lap welding method for general low-pressure fluid conveying spiral seam high-frequency welded steel pipe. Welding steel with spiral welds.
3. The hot rolled steel strip is used as the tube blank, which is often formed by spiral molding and is made of double-sided submerged arc welding or high-frequency welded steel pipe. It is used for the foundation pile steel pipe for civil building structures, wharves, and bridges.
4. The general low-pressure fluid transport is hot rolled steel strip coiled tube, regular temperature spiral molding, using double-sided automatic submerged arc welding or single-sided welding method for water, gas, air and steam and other general low-pressure fluid transport Submerged arc welded steel pipe.
5. The pressure fluid transport is based on the hot-rolled steel strip for tube blanks, regular temperature spiral molding, high-frequency lap welding method used for pressure fluid transmission spiral seam high-frequency welding steel pipe device. The steel tube has strong pressure bearing capacity and good plasticity, which facilitates welding and processing. After a variety of strict and scientific inspections and tests, the use of safe and reliable, large diameter steel pipe, transmission efficiency is also high, and can effectively save the laying pipeline investment. It is mainly used for the laying of pipelines connecting petroleum, natural gas, etc.