What is Welding?
Broadly speaking, welding is a metal fabrication process that uses heat and pressure to join two or more metal components together. When heat is applied, the two metal components are melted, and then allowed to cool in order to fuse together and bond into one. There are lots of different types of welding that are used in the sheetmetal manufacturing industry. This includes MIG, TIG and spot welding.
In this article, we focus on spot welding, which is a valuable technique to master, and if performed correctly by an expert, allows us to join sheets of metal together quickly and seamlessly.
Using Spot Welding to Join Sheets of Metal
Spot welding is often referred to as resistance welding, and is one of the oldest welding techniques. It uses two clamp shaped copper alloy electrodes to concentrate the welding current into a small area. While this is occurring, the welder clamps the sheets of metal tightly, thereby joining them together. In other words, the combination of pressure and heat fuses the metals completely. This type of welding therefore uses both heat and pressure to create the weld, meaning that the welding can be performed without the use of any filler materials.
Copper is used for the welding clamp as it has high thermal conductivity and low electrical resistance, meaning it is very effective at transferring electrodes and generating the heat that is required to create the weld.
Which Metals Can be Spot Welded?
Spot welding can be used almost universally for different types of metal materials. Specifically, low carbon steel or mild steel is often spot welded because it has lower thermal conductivity and higher electrical resistance compared to other metals. Steels which are coated with zinc can also be spot welded, if the electrodes are changed frequently and the surface and welding tip are both kept free from contaminants. Stainless steel, nickel alloy and titanium can also be spot welded.
On the other hand, steels which are higher in carbon are known to be more susceptible to cracking because they form frail or weak microstructures as a result of the weld.
While spot welding can seem fairly straightforward, it is a difficult welding technique to master. The technician must apply both welding current and pressure at the right moment, and with the right intensity to create high quality welds. At E&A Probend, we have mastered spot welding over 20 years of experience in the sheetmetal industry. If you would like to discss how we can help you with your sheetmetal project, please call or email us any time.
