21 Oct 2021
If you are not a welder or someone who has knowledge of the welding industry, but an ordinary person, then you may not know thewelding machine.Welding technology can be seen everywhere, whether in life or in production. , As long as you observe carefully, you will find that welding technology is everywhere. As small as a light bulb, a computer, and a car, as large as a rocket and a spacecraft, welding technology is very important. In the welding process, different welding techniques, the welding materials used will be different. In order to obtain high-quality welded joints, we must first choose welding materials reasonably. We are talking about welding materials including welding rod, welding wire, flux, shielding gas, electrode, solvent and so on.
Today we talk about welding gas. The welding gas mainly refers to the various gases used in welding or cutting. According to the gas used in different welding methods, the gas used in welding can be divided into three categories.
The first category is gas oxygen and acetylene for gas welding. The combustion-supporting gas is mainly oxygen, and the combustible gas is mainly acetylene and liquefied petroleum gas. The welding materials used mainly include combustible gas, combustion-supporting gas, welding wire, gas welding flux and so on. Features The equipment is simple and does not require electricity. The equipment mainly includes oxygen cylinders, acetylene bottles (if acetylene is used as combustible gas), pressure reducers, welding torches, hoses, etc. Since the gas cylinder used to store the gas is a pressure vessel, and the gas is a flammable and explosive gas, this method is one of the most dangerous of all welding methods.
The second category, the shielding gas used for argon arc welding is argon or helium. The commonly used inert gas for argon arc welding is argon. It is a colorless and odorless gas. It is also an ideal shielding gas with a density of 25% higher than that of air. It is beneficial to protect the welding arc during flat welding and reduces the consumption of shielding gas. Argon is also insoluble in liquid metal, so it does not cause pores. . The specific heat capacity and heat conduction ability of argon is small, that is, its own absorption is small, and the heat transfer to the outside is small. The heat in the arc is not easy to lose, which makes the welding arc stable and heat concentrated, which is conducive to welding.
The third category is carbon dioxide gas used in carbon dioxide gas shielded welding. Carbon dioxide is a colorless, odorless, non-flammable gas at room temperature. It has a higher density than air and is slightly soluble in water. It reacts with water to form carbonic acid. The operation is simple in application, suitable for automatic welding and all-round welding. Carbon dioxide gas is easy to produce and low in cost, and it is widely used in various large and small enterprises. Due to the special influence of the zero thermal physical properties of carbon dioxide gas, the weld seam is formed well when short-circuit transfer is used, and the high-quality welded joint without internal defects can be obtained by using welding wire containing deoxidizer.
Gas shielded welding, plasma arc welding, gas welding, cutting, brazing in a protective atmosphere, etc. must use the corresponding gas. The selection of welding gas mainly depends on the welding and cutting methods and the properties of the welded metal. Secondly, factors such as the quality requirements of the welded joint, the thickness of the weldment and the welding position should also be considered. So how should we choose welding gas? First, select the gas according to the welding method. The welding method used is different, and the welding, cutting or shielding gas is also different. Second, select gas according to the material to be welded. In gas shielded welding, in addition to the self-shielded welding wire, it is necessary to select an appropriate shielding gas. From the perspective of production efficiency, adding He, N2, H2, C02, 02 and other gases to Ar can increase the heat input of the base material and increase the welding speed. Third, the selection of shielding gas must match the welding wire. For example, if the CO2 welding wire with a high content of Mn and Si is welded in an argon-rich atmosphere, the alloy content of the deposited metal will be higher and the strength will be increased; on the contrary, if the welding wire used in the argon-rich condition is welded with CO2 gas, the weld Performance is reduced.
From this point of view, if you want to obtain higher quality welding results, you should have a deep understanding of welding materials, so that you can better use welding machines, operate skillfully, master more welding techniques, and obtain perfect welding results. A better welder.
Keywords: welding machine
Originally published 21 Oct 2021, updated 21 Oct 2021.