Protective gas blowing method for laser welding machines

At present, there are two main ways to blow the protective gas for Laser Welding Machine: one is to blow the protective gas on the paraxial side; the other is the coaxial protective gas.

How to choose the two blowing methods is a comprehensive consideration. Generally, it is recommended to use the side blowing protective gas method.

Selection principle of protective gas blowing method

First of all, it needs to be clear that the so-called "oxidation" of the weld is only a common name. In theory, it means that the weld is chemically reacted with harmful components in the air, resulting in the deterioration of the quality of the weld. Usually, the weld metal is at a certain temperature. Reacts chemically with oxygen, nitrogen, hydrogen, etc. in the air.

To prevent the weld from being "oxidized" is to reduce or avoid contact of such harmful components with the weld metal at high temperature, not only the molten pool metal, but from the time the weld metal is melted until the molten metal. The pool metal solidifies and its temperature drops below a certain temperature over the course of the period.

Example

For example, titanium alloy welding can quickly absorb hydrogen when the temperature is above 300 ℃, oxygen can quickly absorb when the temperature is above 450 ℃, and nitrogen can quickly absorb when it is above 600 ℃, so the titanium alloy weld is solidified and the temperature is reduced to 300 ℃ The following stages need to be effectively protected, otherwise they will be "oxidized".

It is not difficult to understand from the above description that the blown shielding gas not only needs to protect the weld pool in a timely manner, but also needs to protect the area that has just solidified that has been welded. Therefore, the side shaft side is generally used. Blow the shielding gas, because the protection range of this method is wider than that of the coaxial protection method, especially the area where the weld has just solidified has better protection.

For engineering applications, not all products can use the side shaft side blowing shielding gas. For some specific products, only coaxial shielding gas can be used, which needs to be carried out from the product structure and joint form targeted selection.