How to choose welding flux for welding machine

18 Oct 2021

As a manufacturing technology, welding plays an important role in the manufacturing industry. No technology can be used by manufacturers for the efficient connection of metals and alloys like welding technology, and produce so many additional products in their products. In the economic development, the welding technology of the welding machine is an indispensable processing method. After entering the 21st century, welding is an important part of the manufacturing industry, and its rapid development has brought unprecedented development opportunities to the welding industry. Now welding is not only widely used in chemical industry, energy, transportation, construction, electronics industry, household appliances, but also makes outstanding contributions to the aerospace, aviation, nuclear industry, shipbuilding, petroleum and machinery manufacturing industries. Welding has developed from a single processing technology to a new comprehensive advanced technology, so the economic, quality and reliability requirements of welding are also getting higher and higher.

The production of high-quality welding structures must be guaranteed by high-quality welding materials. However, there are so many types of welding materials, and their performances and uses are different. How to choose them reasonably? These problems not only directly affect the quality of welded joints, but also affect welding productivity, cost and welders' working conditions. Therefore, we must have a more comprehensive understanding of the performance characteristics of commonly used welding materials, today we are talking about welding flux.

Let me talk about gas welding flux first. What is gas welding flux? Gas welding flux refers to the flux of gas welding. Its function is to protect the molten pool, reduce air intrusion into the molten metal, remove oxides in the molten pool, and increase the fluidity of the molten metal. In the gas welding process, in order to prevent the oxidation of metals and eliminate the oxides that have formed, gas welding flux must be used when welding non-ferrous metals, cast iron, stainless steel and other materials. How do we choose gas welding flux? First, it must have a strong reaction ability to generate low melting point and volatile compounds. Second, the melted flux should have low viscosity and good fluidity, and the melting point and density of slag should be lower than wood and welding wire. Third, it is selected according to the type of oxide produced by the base metal during the gas welding process. Fourth, the selected flux should be able to neutralize or dissolve these oxides. Fifth, the flux should be non-toxic and non-corrosive. Sixth, flux can reduce the surface tension of liquid metal. Seventh, the slag should be easily removed after welding.

Then talk about brazing flux, what is brazing flux? Brazing flux refers to the flux used in brazing, also known as brazing flux. It is to ensure the smooth progress of the brazing process and obtain a firm brazed joint. Except for brazing in vacuum and protective atmosphere or using self-fluxing filler, flux is indispensable in most brazing. So how do we choose brazing flux? First, the melting temperature and minimum active temperature of the flux should be lower than the melting temperature of the flux. Second, it should have sufficient ability to remove the oxide film on the surface of the base material and the solder. Third, the viscosity is small at the brazing temperature and the fluidity is good. Fourth, it has sufficient thermal stability in the brazing temperature range. Fifth, its ratio is less important than that of liquid solder. Sixth, it can well wet the base metal and brazing filler metal.

Let's talk about spray welding flux. What is spray welding? Spray welding is to heat the preheated self-dissolving alloy powder coating to 1000~1300℃ to melt the particles, and the slagging floats to the surface of the coating. The generated borides and silicides are dispersed in the coating to make the particles Achieve good bonding with the surface of the substrate. The final deposit has better impact resistance, wear resistance, corrosion resistance, and a mirror-like appearance. So how do we choose spray welding flux? First, it should have the characteristics of low melting point, which can effectively protect the spray welding molten pool. Second, it has good solid fluidity, a large temperature range and can form a smooth surface on the substrate. Third, it has better plasticity and toughness, and the oxygen content is lower. Fourth, it has a moderate particle size and can wet the metal surface.

The gas welding flux, brazing flux, and spray welding flux described above are welding fluxes used in representative welding techniques. By understanding these, you will have a better understanding of the welding materials used in the welding machine, so that you can use the welding machine handily to obtain a more beautiful weld.

Keywords: welding machine

Originally published 18 Oct 2021, updated 18 Oct 2021.

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