As one of the oldest and most commonly used welding processes, resistance spot welding has long been an effective means of joining metal components with a strong and durable weld. In short, resistance spot welding is the process of joining at least two metal sheets, without the need for any kind of filler metal.
In this guide, we’ll cover some of the more common applications of resistance spot welding, the general process behind the method, a step-by-step guide to the spot welding procedure, and also some of the advantages and disadvantages to this welding method. Read on for our best tips, tricks, and advice on how to utilize this time-tested welding process.
Before we get into the specifics of how resistance welding works and the step-by-step procedure for the welding process, let’s first take a look at some of the base metals suitable for spot welding, as well as some of its common applications in the real world.
Some of the most frequently used base materials for resistance spot welding include stainless steels, titanium, nickel alloys, and low carbon steels.
Higher carbon steels, however, are more prone to brittleness, which can lead to cracking and even a complete separation of the weld.
Stainless steels are, by far, the most spot weldable materials and the most frequently used in spot welding, as well. It is important, though, that you consider the grade of the steel, as some grades of steel are better suited to spot welding than others. Austenitic grades, for instance, are particularly spot weldable. Next would be Ferritic steels. Last, and least suitable for spot welding, are Martensitic steels.
Since the most common use for a resistance spot weld is in the joining of two metal sheets, the method has found widespread use in several different industries. Indeed, resistance spot welding is widely used in aerospace engineering, auto manufacturing, consumer electronics, and, perhaps most significant, in construction.
Simply put, resistance spot welding is the process by which two metal pieces are joined together through a combination of force (that’s the resistance part) and heat. The force and heat are produced by the metal’s natural resistance to an electric current. Essentially, the weld is a result of an electrical current passing through two opposed electrodes and through the base metal you are welding.
Now, let’s move on to the real reason why you’re here: to actually learn the process of resistance spot welding! Here’s our step-by-step guide to the whole spot welding procedure:
1. As with any welding project, be sure to use proper safety gear and follow the safety instructions included with your specific equipment.
2. Align your workpieces. You must ensure that the two (or more) metal pieces to be welded together are aligned exactly with one another. It’s much better to get this down right at the start of the process, as it is exceedingly difficult to remedy misalignment later on.
3. Press on the Electrodes: Position your selected electrodes (be sure you have selected electrodes appropriate for your base materials) onto the chosen workpieces. Most often, the electrodes will be comprised of copper alloys.
4. Turn on Electrical Current: Once the electrodes are properly placed and pressure is added, the electrical current can begin to glow between the electrodes. The immense pressure and heat created by this current will turn the base material into molten metal in order to join the two (or more) pieces.
5. Wait: Now you need to wait an appropriate amount of time for the two parts to join via the molten metal material between them. The amount of time to wait in the step is entirely dependent on factors such as base material composition and thickness. Refer to user guides or other professional guidelines to determine the proper waiting period.
6. Move on to Next Welding Point: Once the pieces have been effectively welded together, you can remove the electrodes and place them on the next point on the base materials where you want to add another weld.
7. Repeat: You can then repeat all of the preceding steps as many times as necessary to get as many weld points as are required for a durable and sustainable joint.
There are certainly many significant advantages to using resistance spot welding as your welding method of choice. Here are some of the benefits that we think are the most important.
Compared to other welding methods, like the use of TIG welders, resistance spot welders are quite affordable. While the welders themselves tend to be cheaper, there is also money to be saved with regard to filler materials. While other welding methods require filler metals to create a bond, this is entirely unnecessary for resistance spot welding.
Resistance spot welding is also a great option if your goal is to create uniform, strong, and durable joints. The process promotes uniformity due to its lack of required filler metals. That is, you are using the metal from your base material workpieces to liquify and join together. There is no need to add any other metal filler material to the joint in order to ensure a proper and sturdy weld. Other methods that require such filler metal can leave you with unsightly weld joints that lack the uniformity and cohesion that you can get with resistance spot welds.
If you’re just getting started with welding, resistance spot welders, much like MIG welders, are a good way to get your feet wet with various welding processes. Since the process can be either automatic or semi-automatic, you don’t need to be as skilled with welding processes to still produce solid welding projects.
Of course, as with any type of welding, there are always downsides, and resistance welders have their own disadvantages. The following items are things you should take into account before embarking on a resistance spot welding purchase and/or project.
We mentioned that resistance spot welding is an economical option for those welders on a budget, and this is true. However, the initial costs for equipment for this method can sometimes get a little pricey. That said, we think the long-term benefits of not having to purchase filler metals will ultimately even out this upfront cost.
While there is an element of cleaning and preparation involved in practically all methods of welding, from TIG welders to MIG welders to arc welders, when it comes to resistance spot welding, some metals require some extra elbow grease before welding. This is especially the case for stainless steel.
Resistance spot welding can be a great method for a wide variety of applications. That said, the thickness of your base material will have a huge bearing on how difficult the process becomes. If you are using thicker metal sheets, you may run into some difficulty with spot welding.
Hi, my name is Gregory! I have been welding practically all of my life and love it. As I have gotten older I have started to weld less and less, so in order to continue my love for welding I created this website. I like to write about my experiences and help you all become welders. I hope that you enjoy the site!
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