What are the ways of welding?

【Summary Description】 What are the ways of welding? Several Electric Welding Techniques there are several kinds of welding welding method? There are 6 kinds of welding methods, namely 1. Electrode arc welding: principle-arc welding method for welding with manual operation electrode. 2. Submerged arc welding (automatic welding): Principle-the arc burns under the flux layer. The heat generated by the arc burning between the wire and the weldment melts the wire, flux and base metal (weldment) to form a weld. 3, carbon dioxide gas shielded welding (automatic or semi-automatic welding): principle: the use of carbon dioxide as a protective gas melting electrode arc welding method. 4. MIG/MAG welding (MIG/active gas shielded welding):MIG welding principle-an arc welding method using inert gas as shielding gas and welding wire as melting electrode. 5. TIG welding (tungsten inert gas shielded welding) principle-under the protection of inert gas, the base metal and filler wire (also without filler wire) are melted by the arc generated between the tungsten electrode and the weldment to form a weld welding method. The electrode does not melt during welding. 6, the principle of plasma arc welding-with the help of water-cooled nozzle on the arc restraint effect, to obtain high energy density plasma arc welding method. What are the ways of welding? Fusion welding is a method of heating the workpiece interface to a molten state during the welding process and completing the welding without pressure. During fusion welding, the heat source will rapidly heat and melt the interface of the two workpieces to be welded to form a molten pool. molten pool... Fusion welding is a method of heating the workpiece interface to a molten state during the welding process and completing the welding without pressure. During fusion welding, the heat source will rapidly heat and melt the interface of the two workpieces to be welded to form a molten pool. The molten pool moves forward with the heat source, and after cooling, a continuous weld is formed to connect the two workpieces as a whole. In the welding process, if the atmosphere is in direct contact with the high temperature molten pool, the oxygen in the atmosphere will oxidize the metal and various alloying elements. Nitrogen and water vapor in the atmosphere enter the molten pool, and defects such as pores, slag inclusions, and cracks will be formed in the weld during the subsequent cooling process, which will deteriorate the quality and performance of the weld. In order to improve the quality of welding, people have developed a variety of protection methods. For example, gas shielded arc welding is to isolate the atmosphere with argon, carbon dioxide and other gases to protect the arc and molten pool rate during welding. Another example is that when welding steel, titanium iron powder with high oxygen affinity is added to the electrode coating for deoxidation, which can protect the beneficial elements manganese and silicon in the electrode from oxidation and enter the molten pool, and obtain high-quality weld after cooling. Pressure welding is under pressure conditions, so that the two workpieces in the solid state to achieve the combination of atoms, also known as solid-state welding. The commonly used pressure welding process is resistance butt welding. When the current passes through the connection end of the two workpieces, the temperature rises due to the large resistance. When heated to the plastic state, the connection becomes one under the action of axial pressure. The common feature of various pressure welding methods is that pressure is applied during the welding process without filling material. Most pressure welding methods such as diffusion welding, high frequency welding, cold pressure welding, etc. do not have a melting process, so there is no burning of beneficial alloy elements like fusion welding, and the problem of harmful elements invading the weld, thus simplifying the welding process and improving the welding safety and health conditions. At the same time, the heating temperature is lower than that of fusion welding and the heating time is short, so the heat affected zone is small. Many materials that are difficult to weld by fusion welding can often be welded by pressure welding to form high-quality joints with the same strength as the base metal. Brazing is the use of metal materials lower than the melting point of the workpiece as a solder, the workpiece and the solder are heated to a temperature higher than the melting point of the solder and lower than the melting point of the workpiece, and the liquid solder is used to wet the workpiece, fill the interface gap and realize the interdiffusion of atoms with the workpiece, so as to realize the welding method. The joint formed during welding that connects the two connected bodies is called a weld. Both sides of the weld will be subjected to welding heat during welding, and the organization and performance changes will occur. This area is called the heat affected zone. Due to the different Welding materials of the workpiece material and welding current during welding, overheating, embrittlement, hardening or softening may occur in the weld and heat affected zone after welding, which also reduces the performance of the weldment and deteriorates the weldability. This requires adjustment of the welding conditions, pre-heating of the weldment interface before welding, and post-weld heat treatment during welding can improve the welding quality of the weldment. In addition, welding is a local rapid heating and cooling process, the welding zone due to the restraint of the workpiece body around and can not be free expansion and contraction, after cooling in the weldment will produce welding stress and deformation. Important products need to eliminate welding stress and correct welding deformation after welding. Modern welding technology has been able to weld no internal and external defects, mechanical properties are equal to or even higher than the connected body of the weld. The mutual position of the welded body in space is called the welded joint. The strength of the joint is not only affected by the quality of the weld, but also related to its geometry, size, force and working conditions. The basic forms of joints are butt joint, lap joint, T-joint (positive junction) and angle joint. The cross-sectional shape of the butt joint weld is determined by the thickness of the welded body before welding and the groove form of the two sides. When welding thicker steel plates, in order to weld through, various shapes of grooves are made at the side so that the welding rod or welding wire can be easily fed. The groove forms include one-sided welding groove and two-sided welding groove. When selecting the groove form, in addition to ensuring penetration, factors such as convenient welding, small amount of filler metal, small welding deformation and low groove processing cost should also be considered. When two steel plates with different thicknesses are butted, in order to avoid serious stress concentration caused by rapid cross-section changes, the thicker plate edges are often gradually thinned to reach the same thickness at the two joints. Butt joints have higher static strength and fatigue strength than other joints. Welding of butt joints is often preferred for connections that work under alternating, impact loads or in low-temperature and high-pressure vessels. The pre-welding preparation of lap joints is simple, easy to assemble, and the welding deformation and residual stress are small, so it is often used on site to install joints and unimportant structures. In general, lap joints are not suitable for working under alternating loads, corrosive media, high or low temperatures, etc. The use of T-joints and corner joints is usually due to structural requirements. Fillet welds with incomplete penetration on T-joints have similar operating characteristics to fillet welds of lap joints. When the weld is perpendicular to the direction of the external force, it becomes a positive fillet weld, at which time the surface shape of the weld will cause different degrees of stress concentration. The bearing capacity of the corner joint is low, and it is generally not used alone. It is only improved when the welding is through, or when there are fillet welds inside and outside. It is mostly used at the corner of the closed structure. Welded products are lighter than rivets, castings and forgings, which can reduce weight and save energy for transportation tools. Welding of good sealing, suitable for the manufacture of various types of containers. The development of joint processing technology, so that welding and forging, casting combination, can be made into large, economical and reasonable cast welding structure and forging welding structure, economic benefits are very high. The welding process can make effective use of materials, and the welding structure can use materials with different properties in different parts, giving full play to the advantages of various materials to achieve economy and high quality. Welding has become an indispensable and increasingly important processing method in modern industry.

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