More types of welding, the current commonly used are the following: 1. Arc Welding Arc welding is the most widely used welding method. It includes: manual arc welding, submerged arc welding, gas tungsten arc welding, plasma arc welding, MIG welding and so on. Most of the arc is burning between the electrode and the workpiece the arc as heat source. In the formation of joint, you can use or may not use filler metal. Electrode is used in the process of melting in the welding wire, the known melting arc welding, such as hand arc welding, submerged arc welding, gas shielded arc welding, tubular wire arc welding, etc.; electrode is used in the welding process does not melt The tungsten carbide, or when called arc welding without melting, such as TIG welding, plasma arc welding and so on. (1) arc welding Hand arc welding of various methods of development of the earliest and is still the most widely used as a welding method. It is based on the external electrodes coated with paint for electrodes and filler metals, welding arc is the end and was burning between the surface of the welding rods. Coatings under the action of the arc heat can produce gas in order to protect the one hand, arc, on the other hand can produce slag covering the weld pool surface, the molten metal to prevent the interaction with the surrounding gas. More important role in slag and molten metal is produced physical and chemical reactions or alloying elements to improve the weld metal properties. Manual arc welding equipment is simple, lightweight, flexible operation. Can be applied to maintenance and assembly of the welding seam in short, in particular, the site can be used for welding difficult to achieve. Manual arc welding electrode equipped with the appropriate applicable to most industrial carbon steel, stainless steel, cast iron, copper, aluminum, nickel and their alloys. (2) SAW Submerged arc welding wire is continuously sent to the time of filling as the electrode and metal. Welding, welding area covered in a layer of granular flux, arc burning under the flux layer, the tip of the wire and the local base metal melting to form a weld. Under the action of heat in the arc, on the part of the flux and molten slag metallurgical reaction with the liquid metal occurs. Slag floating on the surface of the metal bath, on the one hand to protect the weld metal, to prevent air pollution, and with the physical and chemical reaction produces molten metal to improve the performance of the weld metal and extreme; the other hand, the weld metal can slow of cooling. Submerged arc welding can use a larger current. Compared with manual arc welding, its biggest advantage is that the weld quality, high welding speed. Therefore, it is particularly suitable for welding of large parts of the girth seam straight. And most of the mechanized welding. SAW has been widely used in carbon steel, low alloy steel and stainless steel welding. As the cooling rate of slag can reduce the joint, so some of the high-strength structural steel, high carbon steel submerged arc welding, also can be used. (3) gas tungsten arc welding This is a non-MIG arc welding, tungsten and the workpiece is the use of electric arc between the metal melting and the formation of the weld. TIG welding process does not melt, only play the role of the electrode. At the same time sent by the welding torch nozzle for the protection of argon or helium. Also necessary to add other metals. Internationally known as TIG welding. Gas tungsten arc welding as well to control the heat input, so it is connected and backing weld sheet metal as a great way. This method can be used for virtually all metal connections, especially for welding aluminum and magnesium which can form refractory oxides such as titanium and zirconium metal and the active metals. The welding seam of high quality, but compared with other arc welding, the welding speed is slower. (4) plasma arc welding Plasma arc welding is a non-melting arc welding. It is the use of compressed between the electrode and the workpiece the arc (called the forward transfer of the arc) to achieve welding. Is usually used in tungsten electrodes. Plasma arc generated plasma gas can be argon, nitrogen, helium, or in which both the mixture. Also protected with an inert gas through the nozzle. Welding filler metal can be applied, it may not add filler metal. Plasma arc welding, arc because of its straight, energy density, and thus the arc penetrating ability. Plasma arc welding holes generated effects, for a certain thickness range of most metals can not open butt, and to ensure uniform penetration and weld. Therefore, the production rate of plasma arc welding, weld quality. However, plasma arc welding equipment (including nozzle) more complicated, the control of welding parameters demanding. Gas tungsten arc welding of most metals can be, can by plasma arc welding. In contrast, for 1mm below the welding of thin metal with a plasma arc welding can be easily carried out. (5) MIG arc welding This welding method is the use of continuous feeding of the wire and the workpiece as heat between the combustion of the arc, the welding torch nozzle for gas shielded arc welding. MIG arc welding is usually used to protect the gases: argon, helium, CO2 gas or mixture of these gases. Argon or helium gas for the protection referred to as metal inert gas shielded arc welding (MIG for short in the international welding); to inert gases and oxidizing gases (O2, CO2) to protect the gas mixture, or CO2 or CO2 + O2 gas mixture for the protection of gas, or CO2, or CO2 + O2 gas mixture for the protection of gas, referred to as melting active gas arc welding (referred to as MAG in the international welding.) MIG arc welding of the main advantages of various locations can be easily welded, but also with the welding speed, deposition rate and so on. Melting active gas arc welding applied to most of the major metals, including carbon steel, alloy steel. Metal inert gas welding for stainless steel, aluminum, magnesium, copper, titanium, zirconium and nickel alloys. This can also be used for arc welding spot. (6) tubular wire arc welding Tubular wire arc welding is also sent to the wire using the continuous burning of the arc between the workpiece to be welded to the heat source, can be regarded as MIG welding type. Tubular wire is used in welding, pipe built with various components of the flux. Welding, plus the protection of gas, mainly CO. Decomposition or melting heat flux plays a slagging protection solution pool, alloying and arc stability and so on. In addition to tubular wire arc welding with the MIG arc welding of the advantages, the role of the flux tube, so that more advantages in metallurgy on. Tubular wire arc welding of various ferrous metal can be applied to most of the welding joints. Tubular wire arc welding in some advanced industrial countries have been widely used.
Electrical steel belt in the seam causes and measures: electrical steel weld quality optimization:
The production of electrical steel belt weld problems occur, resulting in product obsolescence, and in severe damage caused by roll, in addition to the bad welding, weld after rolling there were many small holes, affect subsequent production use. High Si content in steel, the phenomenon is more evident.
Weld belt of reasons:
1, serious adverse substrate flatness, resulting in missing butt weld strip. 2, strip welding, finishing ineffective, there is level at the weld, resulting in incentives. 3, the welding process and parameters unreasonable. Measures: 1 to enhance detection of silicon content, silicon content electrical steel concern, according to Si content in a timely manner to adjust the welding parameters on welding. 2 drip function input. High levels of silicon electrical steel, the welding process, a large amount of oxide slag, you need to clear the drop of oil added to keep cleaned. 3 to enhance weld quality inspection, to prevent bad shape due to the reasons for the adverse weld the mill. 4 equipment to ensure that, before welding to ensure that the status and location of finishing back in good condition, bail welding electrode relative to the limit does not exceed the number. 5, the adjustment of welding parameters. When using the flash butt welding, should pay attention to voltage levels, flash time, the top length of the parameters, while the initial gap welding is welding control points should be precisely controlled in order to facilitate welding. 6 Annealing aspects. High silicon steel brittle, deformation in the cold when the strip substantially, resulting in welds prone to fracture, should be annealed carbon steel electrode, the weld extension to improve performance.