Common steel pipe welding methods and their characteristics

Steel pipe welding is a process of heating pressurizing or both, to make the steel pipe achieve atomic bonding and form a permanent joint. In production, welding technology is relied on to varying degrees. Welding directly affects the quality, reliability, production cost, and efficiency of the product. With the development of science and technology, many welding methods have been produced. At present, the more common steel pipe welding methods are: arc welding, tungsten inert gas welding, carbon dioxide gas shielded welding, and submerged arc welding.

1. Arc welding

Arc welding is a welding method that uses manual manipulation of the welding rod for welding, commonly known as hand-held welding. Arc welding uses a stable burning arc established between the welding rod and the workpiece to melt the welding rod and the workpiece, thereby obtaining a firmly welded joint. During arc welding, the coating of the welding rod continuously decomposes and melts to generate gas and slag, which protects the end of the welding rod, the arc, the molten pool, and its surrounding areas, and prevents the harmful effects of the atmosphere on the molten metal. The electrode core is continuously melted under the action of arc heat, enters the molten pool, and forms the filler metal of the weld.

2. Tungsten inert gas welding

Tungsten inert gas welding is a welding method that uses tungsten rods as electrodes and delivers argon gas for protection. It belongs to tungsten inert gas shielded welding (TIG). The argon arc welding we usually refer to is mostly manual tungsten inert gas welding, because among various argon arc welding, manual tungsten inert gas welding is the most common. During tungsten inert gas welding, argon gas is continuously ejected from the nozzle of the welding gun, forming a protective layer around the arc to isolate the air to prevent the tungsten electrode, the molten pool, and the adjacent heat-affected zone from being oxidized and contaminated by air, thereby obtaining a high-quality weld. Tungsten rods are used as welding electrodes and do not serve as welding filler metal. During welding, the welding wire is fed in melts as filler metal. In certain cases, welding is also performed by directly melting the parent material without welding wire.

3. Carbon dioxide gas-shielded welding

Carbon dioxide gas shielded welding is a melting electrode gas shielded welding that uses carbon dioxide as a shielding gas, commonly known as two-shield welding. During the welding process, the wire is automatically fed in by the wire feeding mechanism. The wire is used as both an electrode and a welding filler. While the wire is continuously melted, the wire feeding mechanism continues to feed and replenish it. The welding depth of the two-guard welding is large, the welding deformation is smaller than that of the hand-held welding, the welding efficiency is high, and the welding cost is low.

4. Submerged arc welding

Submerged arc welding is a method of welding in which the arc burns under the flux layer. During the welding process, the arc and the welding area are covered by the flux, and the welding pool is protected by the slag formed by the flux to block the intrusion of air. Submerged arc welding has high production efficiency, good welding quality, good working conditions, no arc light can be seen during the welding process, low noise, and less smoke. It is a safe and green welding method.

The above are the four most commonly used steel pipe welding methods. Some steel pipe welding methods are more widely used in specific industries. With the development of science and technology and the summary of practical applications, steel pipe welding methods are also constantly innovating and improving. In practical applications, relevant conditions can be combined to comprehensively consider applicability, economy, quality, and efficiency, and select the most suitable steel pipe welding method.