How to deal with the welds and welding points of 304 stainless steel?

Some customers who make mechanical equipment have reported that some equipment has rusted at the welding point after being welded with 304 stainless steel strip argon welding. The reasons need to be analyzed from all aspects, and then the right medicine can be prescribed to find a solution. The following editor will introduce them one by one. Analysis. Welded pipes are made through welding process. The welds of 304 stainless steel pipes will leave orange, blue or black welds after welding, which are difficult to remove. The presence of solder joints not only affects the appearance, but also accelerates corrosion in the atmosphere and reduces the corrosion resistance of the material, which will have a certain impact on actual use. This article will introduce in detail how to deal with welds and welding points on 304 stainless steel pipes for reference only.

After welding of 304 stainless steel pipes, in order to improve the appearance of the product, it is usually necessary to clean and repair the surface welds. If these welds are not treated, they will have a rough appearance and affect the overall appearance. So that is to say, in the production process, weld treatment is an important part.

If argon welding is used, it depends on whether auxiliary materials are used, whether the carbon content of the 304 stainless steel strip meets the welding requirements, and whether low-carbon steel such as 304L stainless steel strip is needed. It is preferred to use steel with a lower carbon content and nickel. Stainless steel material with higher quality is preferred.

Grinding the weld can make the weld look better without affecting the effective height of the weld. Mechanical polishing is the grinding and polishing process performed by tools such as sandpaper, oilstone, canvas, felt or belt, as well as manual operation, or manual grinding and mechanical grinding with the help of mechanical power such as electric tools. Polishing abrasives can be made of tantalum oxide, iron oxide, etc., or they can be made into grinding media according to a certain proportion of chemical components.

This method is practical, energy-saving, and environmentally friendly, and has a good effect on grinding welds, but it is easy to rust after grinding (the metallographic structure changes), the plane effect of 304 stainless steel pipes is poor, many corners are difficult to polish and polish, and the labor cost is high .

304 stainless steel pipe is completely pickled and passivated to remove rust, scale, welding spots and other dirt. After treatment, the surface of the stainless steel pipe is uniformly silver-white, which greatly improves the corrosion resistance of stainless steel. No professional equipment is required and the operation is simple. The pipe can be soaked in a tank filled with stainless steel pickling and passivation liquid. It is suitable for all kinds of large, medium, small, complex and special-shaped pipes, suitable for small batch soaking as well as large batch soaking, with short time, good efficiency and low cost. Low, uniform and stable color. However, some types of pickling and passivation liquids have peculiar smells and require masks to be worn during operation. The treated 304 stainless steel pipe needs to be rinsed and the wastewater needs to be neutralized in a centralized wastewater pool.

Electrolytic polishing is a method that utilizes the electrochemical desorption phenomenon produced by the anode in the electrolytic cell to selectively dissolve the micro-protrusions on the anode to form a smooth surface. This technology can greatly improve the surface quality of metals, making them more corrosion-resistant and brighter.

The polishing speed is fast, the cost is low, the efficiency is high, the quality is good, and it is suitable for mass production. One potion can be used for a long time. Non-standard electrolytic cells and hangers can be made according to the output and size of 304 tubes. There is no irritating smell during production, but a small amount of hydrogen is produced. Molecules, pay attention to ventilation, wastewater treatment must be done after production, and environmental protection requirements are high.

Its principle is similar to electrolytic polishing, but it is more portable, easy to operate, more efficient, has less color difference, and no excessive irritating odor. But it can only be done on the weld and cannot be performed on a large area. It is divided into two categories: manual dispensing and automatic dispensing. The manual one saves dispensing but wastes brush heads, while the automatic one saves brush heads but wastes dispensing. You can choose according to your own development situation.

The default common solutions are mostly these: weld treatment agent, weld treatment liquid, stainless steel passivation paste, stainless steel passivation liquid, etc. These are common treatment methods and the prices are relatively low. The stainless steel pickling liquid can be used as appropriate, of course, it can also be welded

In addition, the root causes and solutions for the darkening of stainless steel pipes after pickling are as follows:

There are two possible reasons why stainless steel pipes turn black after pickling: one is that the oil stains are not cleaned up, and a lot of residues are adsorbed on the surface of the stainless steel pipe after pickling. The second is excessive pickling, and the stainless steel causes the surface of the pipe to turn black. If the blackening can be wiped off by hand, you can directly use the film stripping liquid, which can quickly remove the gray and black substances caused by pickling. Directly apply this solution to the surface of the stainless steel parts where it turns black after pickling, and then clean it with clean water after the gray-black color fades.

The above is the main content of the weld of 304 stainless steel pipe. The specific treatment method should be selected according to the 304 pipe, and more attention should be paid during use to do a good job of rust prevention of the weld to prevent rust and cracking.