Concept of TIG welding
TIG welding (Tungsten Inert Gas Welding), also known as non-melting extremely inert gas shielded arc welding. Whether it is manual welding or automatic welding of 0.5 to 4.0mm thick stainless steel, TIG welding is the most commonly used welding method. TIG welding with filler wire is often used for bottom welding of pressure vessels because the air tightness of TIG welding is better and can reduce the pores in the weld seam during pressure vessel welding. The heat source of TIG welding is a DC arc, the working voltage is 10 to 95 volts, but the current can reach 600 amps. The correct connection method of the welding machine is that the workpiece is connected to the positive electrode of the power supply, and the tungsten electrode in the welding torch is used as the negative electrode. The inert gas is usually argon.
Advantages of seamless pipe TIG welding technology
① The variety and quantity of metal materials for TIG welding are actually unlimited. They have many characteristics in shape and form, area and other dimensions, bonding strength and performance. All of these determine the application of TIG welding technology to metal materials. There are many applications with excellent results in welding.
②Ar is one of the most stable inert gases with good protection effect. Gas protection replaces slag protection, and the weld is clean and slag-free. The inert gas argon forms a closed airflow around the molten pool and arc, effectively preventing the intrusion of harmful external gases and thereby obtaining high-quality welding joints.
③The TIG welding arc is compressed and cooled by the argon gas flow, and the arc is concentrated, which can ensure the penetration of the root of the seamless pipe weld, the heat-affected zone of the joint is small, and the tendency of the weldment to deform and crack is small. It is especially suitable for welding steel materials with a high tendency of air quenching.
④Ar is insoluble in metals and does not react with metals, so there is generally no burning loss of alloy elements. TIG seamless pipe welds are particularly pure, and there is no welding slag in the welded pipe joints. The weld quality is better than that of oxyacetylene gas welding and electrode arc welding.
⑤ Open arc welding, the molten pool is clearly visible, the operation is easy to master, and it is easy to realize automation.
⑥The argon gas flow has a flushing effect on the welding area, speeding up the cooling rate of the welded joint, improving the structure and performance of the joint, and reducing the residual deformation of the weldment after welding.
⑦Ar is a monatomic gas with small heat capacity, low thermal conductivity and low heat consumption. It is very beneficial to stable arc combustion. Even under conditions of small current and long arc, the arc is still very stable, easy to operate, and the quality of the weld is easy to control. It is applicable Welding in all positions of difficult-to-weld small-diameter pipes.
Because TIG welding has good welding quality and is easy to operate, in recent years, it has become a common method for power generation companies to weld heating surface seamless pipe when installing and overhauling boilers. Under on-site maintenance conditions, subject to the limitations of the welding position and operating space, the commonly used process methods are TIG welding, arc welding of the bottom electrode, or TIG full argon arc welding.
TIG welding (Tungsten Inert Gas Welding), also known as non-melting extremely inert gas shielded arc welding. Whether it is manual welding or automatic welding of 0.5 to 4.0mm thick stainless steel, TIG welding is the most commonly used welding method. TIG welding with filler wire is often used for bottom welding of pressure vessels because the air tightness of TIG welding is better and can reduce the pores in the weld seam during pressure vessel welding. The heat source of TIG welding is a DC arc, the working voltage is 10 to 95 volts, but the current can reach 600 amps. The correct connection method of the welding machine is that the workpiece is connected to the positive electrode of the power supply, and the tungsten electrode in the welding torch is used as the negative electrode. The inert gas is usually argon.
Advantages of seamless pipe TIG welding technology
① The variety and quantity of metal materials for TIG welding are actually unlimited. They have many characteristics in shape and form, area and other dimensions, bonding strength and performance. All of these determine the application of TIG welding technology to metal materials. There are many applications with excellent results in welding.
②Ar is one of the most stable inert gases with good protection effect. Gas protection replaces slag protection, and the weld is clean and slag-free. The inert gas argon forms a closed airflow around the molten pool and arc, effectively preventing the intrusion of harmful external gases and thereby obtaining high-quality welding joints.
③The TIG welding arc is compressed and cooled by the argon gas flow, and the arc is concentrated, which can ensure the penetration of the root of the seamless pipe weld, the heat-affected zone of the joint is small, and the tendency of the weldment to deform and crack is small. It is especially suitable for welding steel materials with a high tendency of air quenching.
④Ar is insoluble in metals and does not react with metals, so there is generally no burning loss of alloy elements. TIG seamless pipe welds are particularly pure, and there is no welding slag in the welded pipe joints. The weld quality is better than that of oxyacetylene gas welding and electrode arc welding.
⑤ Open arc welding, the molten pool is clearly visible, the operation is easy to master, and it is easy to realize automation.
⑥The argon gas flow has a flushing effect on the welding area, speeding up the cooling rate of the welded joint, improving the structure and performance of the joint, and reducing the residual deformation of the weldment after welding.
⑦Ar is a monatomic gas with small heat capacity, low thermal conductivity and low heat consumption. It is very beneficial to stable arc combustion. Even under conditions of small current and long arc, the arc is still very stable, easy to operate, and the quality of the weld is easy to control. It is applicable Welding in all positions of difficult-to-weld small-diameter pipes.
Because TIG welding has good welding quality and is easy to operate, in recent years, it has become a common method for power generation companies to weld heating surface seamless pipe when installing and overhauling boilers. Under on-site maintenance conditions, subject to the limitations of the welding position and operating space, the commonly used process methods are TIG welding, arc welding of the bottom electrode, or TIG full argon arc welding.
