Welders can manipulate multiple welding techniques to do the same job virtually. They can apply metal inert gas (MIG) welding, metal-cored arc welding (MCAW), or gas tungsten arc welding (GTAW). Still, spray arc welding is the nearest technique to form fillet and non-positioned butt welds as this technique enhances the welder’s efficiency.
Spray Arc Welding: An Overview
In this welding technique, the welder has to disseminate metal to welds from a wire or electrode. The minimal amount of molten metal droplets goes through the electric arc to the joint or weld you are working on.
Basically, this technique is suitable for welding thicker metals like filler and unpositioned butt welds. It is not good for welding applications in which there is a chance of getting hit by molten metal droplets because it can be dangerous.
To clarify this technique, we can say that spray arc welding is a technique in which spray travels through an electric arc and then reaches the joint. Moreover, this procedure lowers the splatter of molten matter and forms a weld with excellent smoothness.
What is the process of spray arc welding?
The procedure involves huge voltage and amperage, so the wire, when coming in contact with the base metal, generates an electric current before it hits the surface of the metal. This electric current elevates the wire temperature and melts it. After that, this molten metal then flows with the electric arc that falls over the base metals in the form of tiny droplets.
The shiny side of this technique is it will result in a high metal deposition rate when you use an appropriate tip to metal distance, metal, the diameter of the wire, and shielding gas. Moreover, the process must involve high current as it ensures that less welding spatter will be produced.
What are the advantages of spray arc welding?
Spray arc welding is a convenient technique. The following are some key benefits you will get by applying this procedure:
- Excellent metal penetration and fusion
- Capable of utilizing thick electrode wires
- Impressive weld bead appearance
- The production of weld spatter is very low
- Greater metal deposition rates
What are the drawbacks of spray arc welding?
Despite striking benefits spray arc welding gives over other welding techniques, it has the following drawbacks as well:
- It doesn’t have open root abilities
- You will be restricted to flat and straight line fillet weld positions
- It is suited for welding on metals with thickness above ⅛ inch (3mm)
As it creates bigger weld pools which restrict it to only a few applications. Other than that, it is not an ideal procedure if you have to weld thin metal sheets as it manipulates excessive heat, which will burn the metal.
How to choose the right shielding gas?
The below-given factors will affect your selection of shielding gas:
- Technicalities of the welding process
- Rate of welding fume production
- Position of weld
- Bead penetration
- Cleaning after welding process takes place
- Control over spatter
- Bead profile
- The efficiency and deposition rate of filler metal
The combination of shielding gas for spray arc welding will rely on the type of electrode or metal you are going to use in the process. In general, all the shielding gas combinations for this technique must have a high concentration of argon, like 80 percent and above.
Most importantly, the shielding gas has a significant impact on the metal’s reactivity rate. Moreover, the gas which is highly reactive will intensify the weld puddle fluidity. The speed of the weld puddle increases, probably not in control for you, which is hazardous.
Why is shielding gas important?
It acts as a protection layer between the electric arc and the atmosphere, which saves the weld from environmental contamination. The nitrogen and oxygen present in the air contaminate the weld by reacting with it and producing awful fumes. Apart from containing the weld, the deficiency of shielding gas also causes various problems.
When you have to weld thick metals which have a higher melting point not position restricted, then you should employ the spray arc welding technique. Moreover, this arc welding technique is beneficial from the safety point of view because the generation of welding spatter is minimal. We hope that you now have an in-depth understanding of spray arc welding and its applications and requirements.