What factors affect the effectiveness of protective gas during welding of thin-walled stainless stee

When performing argon arc welding on thin-walled stainless steel pipes, it is necessary to pay attention to the influence of the protective gas used. Since its protective gas argon is flexible, it is very easily disturbed and damaged by external factors. In order to obtain excellent protection effects, the following aspects need to be paid attention to.

The first is the gas flow rate. Theoretically, the greater the gas flow rate, the stronger the protective layer's ability to resist the influence of air. However, in fact, when the gas flow rate is too large, the protective layer will form irregular flows, which will easily cause air to be involved. It weakens the protective effect, thereby affecting the quality of the weld and also wastes gas. Therefore, it must be selected according to the actual situation during welding.

The second is the nozzle diameter. The nozzle diameter is proportional to the gas flow rate. As the nozzle diameter increases, the gas flow rate increases at the same time. At this time, the protected area will inevitably increase, and the protection effect will be better. However, when the nozzle is too large, it will hinder welding in certain positions or block the welder's sight, which will affect the welding effect and quality. In addition, the increase in ammonia consumption will increase the project cost, so the nozzle diameter should be determined according to the thickness of the pipeline.

Third, you need to observe the distance between the nozzle and the workpiece. Generally speaking, the farther the distance, the worse the protection effect, and vice versa, the better. But in fact, the distance between the nozzle and the workpiece can only be determined based on the extension length of the tungsten rod. It is determined that if the extension length of the tungsten rod is 2mm-3mm, the distance from the nozzle to the workpiece is 2mm-3mm. However, such an extended length cannot meet the requirements in the welding of thin-walled stainless steel pipes. When the extension length of the tungsten electrode is 8mm-10mm in the test, the distance from the nozzle to the workpiece is 10mm-13mm. Using thin-walled and small-diameter stainless steel pipes, this method can obtain a narrower weld, with a smooth surface and penetration of the root. , there is no convex and concave phenomenon, and the double-sided molding effect is good.

The fourth is the welding speed and external air flow. When performing argon arc welding, because the welding torch itself moves very fast, if it is attacked by positive air flow, the protective gas may deviate from the protected molten pool, and the protection effect will be significantly worse. . Try not to operate outdoors as much as possible. If you really need to operate outdoors, use a windshield and pay attention to controlling a certain welding speed.

The last step is to fill the stainless steel pipe with hydrogen for protection. 10-20 seconds before arc ignition, you can choose to start the switch air supply threshold to remove the air in the stainless steel pipe and adjust the flow rate required by the flow meter. Small pipes can be fully charged and large pipes can be fully charged. Large diameter pipes can be partially filled with argon to reduce the overall consumption of argon.