304 stainless steel welded pipe is often blackened in the position of the weld during use and production. So is there a way to eliminate this situation? What is the reason for this? Let ’s analyze in detail The specific reason:

1. Insufficient argon protection due to the following reasons: the gas contains oxygen and the gas is impure. Response: to ensure the quality of argon.

2. The welding port is not cleaned before welding, and there are impurities such as oil on the stainless steel weldment, which causes the welding to blacken. Response: Welding parts should be carefully cleaned before welding.

3. The protective gas delivery pipeline is damaged, and other gases are mixed in, causing oxidation during welding. Response: Check for leaks, block the welding nozzle of the welding gun, press the gas supply switch of the welding gun, (be careful of electric shock). Wait a moment and check if there is pressure. It can be observed from the pressure gauge and pressure gas column installed on the argon gas bottle.

4. Insufficient supply of argon gas. Response: Observe the flow rate of the pressure gauge and pressure gas column. When the pressure is insufficient, replace the argon gas bottle

5.For the control of the flow rate of argon gas during welding, the timing of the gas supply and the gas stop, the adjustment of the welding current in the welding switch time, the distance between the tungsten needle and the weldment during welding, the selection of the tungsten needle, and the temperature of the weld pool , Welding process parameters such as the matching of welding wire and weldment and the welding technique are directly related to the welding process level.

Regarding the welding requirements for argon arc welding: 1. Air supply in advance: Before welding, the gas is supplied first and then the weldment is welded. In order to ensure the protection of the welding part by argon gas to prevent oxidation2. Delayed gas supply: After the welding gun is received, the muzzle should not leave the welding part of the weldment and continue to supply gas to ensure that the weld seam and surrounding parts of the weldment are not oxidized by high temperature

3. Control of 304 stainless steel welded pipe torch switch: For stainless steel plates, especially thin plates, continuous welding with large current is not allowed during welding for a long time, and spot welding is used. If the current is too large and the welding speed is too slow, the weld seam will be blackened. Therefore, the current should be selected according to the thickness of the plate, the tungsten needle according to the current, the porcelain nozzle according to the tungsten needle, and the gas volume according to the porcelain nozzle. The welding speed should be fast and the technique should be accurate.

4. Technique: The distance between the tip of the tungsten needle and the weldment, the tungsten needle is close to the weldment, and the weld seam is black; the tungsten needle is too far away from the weldment, the weld seam is also black. The main reason is to ensure the stability and strength of the welding arc during welding

5. Selection of tungsten needle:

① Try to use tungsten needles with yellow and white marks as far as possible, and the quality of tungsten needles must be reliable

② The tungsten needle should be kept sharp during use. The reason is that the tungsten needle is blunt and the current cannot be concentrated.

The stability of the arc during welding is not easy to maintain and easily diverges.

6. Welding pool temperature control: It is related to the welder's technique and gun speed. The temperature of the molten pool meets that the welding of the weldment is closely related to the size of the current, and it is related to the speed of the gun when it is not oxidized before cooling.The speed of the gun is cooled while the speed of the gun is to ensure that the argon gas protects the front molten pool and is not oxidized by high temperature .

7. Welding wire material should be selected according to the material of the weldment to ensure the uniformity of the material and to avoid welding and blackening due to material differences.