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Through after-sales feedback from customers, some customers who specialize in mechanical equipment use 304 stainless steel strips to weld certain equipment, and the welding points are prone to rust. Why do the welding points of 304 stainless steel strips used in mechanical equipment rust? What should we do? In fact, there are many reasons why the welding points of 304 stainless steel strips rust after welding. HUA STEEL will briefly analyze the reasons and give the correct preventive measures. If you use argon welding when welding machinery and equipment, you need to focus on whether the carbon content of the 304 stainless steel strip can meet the welding requirements and whether auxiliary materials are used. If the carbon content in the 304 stainless steel strip is relatively high, it will easily cause intergranular corrosion during welding. Therefore, customers who need welding should prefer steel types with low carbon content and higher nickel content, such as 304L stainless steel. Hua steel introduces 304L stainless steel, which is a derivative of 304 stainless steel. Except for the carbon content being less than 0.03%, the other components, properties and application range are almost the same. It also has the ability to resist intergranular corrosion that 304 stainless steel does not have, and is suitable for welding processes. During welding, the lower carbon content of 304L stainless steel reduces the carbides precipitated in the heat-affected zone near the weld, effectively improving the stainless steel’s ability to resist intergranular corrosion and extending the service life of the stainless steel weld. Therefore, the use of 304L stainless steel can effectively reduce welding corrosion. However, some customers who specialize in mechanical equipment prefer 304 stainless steel. In that case, the following points should be noted during welding to avoid rust as much as possible. 1. When welding, use automatic argon arc welding with narrow weld seams and shorten the residence time in the sensitization temperature zone. Generally speaking, the sensitization temperature range should be controlled between 450℃ and 850℃. 2. Use water to quickly cool the welding area to effectively prevent intergranular corrosion caused by welding of 304 stainless steel strips. 3. Shorten the welding time and reduce the duration of high temperature of the weld, which will help improve the ability of 304 stainless steel strips to resist intergranular corrosion and thermal cracking. 5. When performing multi-layer welding, wait until the weld layer cools to about 600 degrees before welding the next one. 6. Use a relatively small line energy. Under the same conditions, the current used should be 10-20% smaller than that of ordinary steel. The material rack should try to swing vertically as much as possible to avoid lateral swing. 7. If conditions permit, try to use pulse welding. This welding method can reduce overheating at the welding point and help improve the corrosion resistance and crack resistance of 304 stainless steel strips. 8. Regardless of whether welding is completed or interrupted, the arc closing speed should be slow, and attention should be paid to filling the arc pit to prevent crater cracks. 9. When performing filler welding, the filler wire should be biased towards the arc and quickly withdrawn to avoid adhesion between the filler wire and the edge of the molten pool. 10. The surface of the weld should be cleaned to ensure that the weld position is relatively smooth and there is no unevenness. After welding, the residue should be thoroughly removed. Operators should operate correctly, avoid random arcing, avoid spattering, and pay attention to the protection of the back part during welding to avoid back oxidation. What should I do if the welding point of 304 stainless steel strip is rusted? It can be treated according to the different degrees of rust. If it is just a slight rust spot, you can use toothpaste to remove it. Squeeze a little toothpaste on a towel, dip some clean water and wipe the rusted area repeatedly. If the rust is a little serious, it is recommended to use polishing and waxing. The above is the cause and solution of rust on 304 stainless steel welds introduced by HUA STEEL. I hope Zyta’s introduction can help you. If you want to know more common problems related to stainless steel, please continue to follow us HUA STEEL CO.,.