Argon is a noble gas widely used in industry. It is very inert in nature and neither burns nor supports combustion. In aircraft construction, shipbuilding, nuclear power industry and machinery industry, argon is often used as a welding shielding gas for special metals (such as aluminum, magnesium, copper and its alloys and stainless steel) to prevent welding parts from being oxidized or nitrided by air. 1. Aluminum Industry Replaces air or nitrogen for creating an inert atmosphere during aluminum manufacturing; helps remove unwanted soluble gases during degassing; and removes dissolved hydrogen and other particles from molten aluminum. 2. Steel production Used to replace gas or steam and prevent oxidation in process flow; Used to stir molten steel to maintain constant temperature and composition; Helps to remove unnecessary soluble gases during degassing; As a carrier gas, argon can be used to pass chromatography The composition of the sample is determined by the method; argon can also be used in the argon-oxygen decarburization process (AOD), which is used in the finishing of stainless steel to remove carbon monoxide and reduce the loss of chromium. 3. Metal processing Argon is used as an inert shielding gas in welding; to provide oxygen- and nitrogen-free protection during annealing and rolling of metals and alloys; and to flush molten metal to remove holes in castings. 4. Welding gas. As a protective gas in the welding process, argon can avoid the burning of alloy elements and other welding defects caused by it. Therefore, the metallurgical reaction during the welding process is simple and easy to control, which ensures the high quality of welding. Based on the laser remelting test of HT250 gray cast iron, the formation mechanism of pores in the remelting zone of the sample under different atmospheric protection conditions was studied. The results show that: under the protection of argon, the pores in the remelting zone are precipitation pores; in the open state, the pores in the remelting zone are precipitation pores and reaction pores. 5. Other uses. Electronics, lighting, argon knives, etc.