Cast Iron refers to a group of alloys of iron and carbon. The percentage of Carbon ranges from 2% to 4%. Cast Iron has a variety of uses which are as a result of its unique characteristics.
Although this outstanding parameters has made it very useful, it has on the other hand made it very difficult yet very necessary to weld especially due to brittle nature of some of the types. However, it is not impossible to weld. Below are guidelines on how to MIG Weld Cast Iron.
How to Mig Weld Cast Iron
1. Metal Inert Gas (MIG) Welding
Metal Inert Gas (MIG) welding, also known as Gas Metal Arc Welding (GMAW) is a process by which an electric arc forms in the middle of an electrode and the metal. This causes the metal to melt which in turn causes them to join.
Mig welding is fast and undoubtedly produces a very high quality weld. The process is also simple and gives the best results as expected.
2. Gathering materials
As you prepare to Mig weld your cast iron. It is important to gather all the necessary materials you may need for the process to be effective.
Check to ensure you have things such as safety protective gears, welding machine and the metals and substances to be Mig welded.
Also check and ensure that the power source is available and it is enough to perform the entire process. Ensure that you have done proper setup of the welding machine and you take into consideration all the measurements required and adjusted all the adjustments.
3. 1st Step
Safety is the first thing to look at before you start to Mig weld cast iron. Welding is a very demanding task that has so many risks involved. This is due to the heavy machines, blunt and sharp objects and even the very high temperatures and harmful gases involved.
Here, safety is key. Ensure that you are dressed in the right protective clothing such as gloves, glasses, welding jackets among others. This helps greatly reduce welding related accidents.
4. 2nd Step
Cleaning the parts you are about to weld is a very important step regardless of the method of welding or even the type of the metal.
In as much as in some of the methods you get away with dirty surfaces, it is always imperative to clean as this results to an extremely eminent weld.
Remove the dirt thoroughly but carefully to ensure that the area you are about to weld has no foreign materials.
This helps remove the entrapped gas which ensures that the joint is stronger and will thus serve you for a longer period of time.
5. 3rd Step
At this stage, you will attach the patch. (In this case, the patch can be the detached part of the work piece). Place it in between the integral part and ensure that it is firm enough and in a position that allows you to weld.
Placing the patch in the wrong position result to poor welding and results to a weak joint that only serves for a very short time. It may also alter the efficiency of the appliance that is being welded.
6. 4th Step
You can now begin welding. When welding cast iron, temperature is key. For this reason, welding is done in short welds approximately 2.54 cm (0.025m) after each weld, it is important to wait for around 35 seconds (0.6 minutes).
This gives it ample time to cool thus preventing the temperatures from building up which in turn result to low productivity. The key point in this process is to keep it slow and low.
Cast iron does not stretch or deform. However, this sacrifices its resistance to cracking. Temperatures above 7600 C (1400 Fahrenheit) stresses the metal resulting to cracking.
7. 5th Step
At this stage, you do studding. This involves drilling holes on the surface of the work piece. This allows you to use screws which makes the weld more successful. After this, weld the screws in place to ensure that the patch is held in place.
Studding results to a very strong weld. It is also cost efficient and provides fast firm attachment. This complements Mig welding.
8. Seal the cracks
Presence of cracks right after welding cast iron does not mean poor weld whatsoever. Cast iron is very delicate and it easily cracks. This implies that it is practically impossible not to find cracks after welding in as much as the right procedure was strictly followed.
Search for the cracks and seal them using a sealing compound for the joints to be water tight. This will in turn make them to last longer. After sealing all the cracks, you can then clean the machine and let the place be clean as it was before.
Finally, there are other methods that are used to weld Cast Iron perfectly. This include using a nickel rod, using stick welder or even using an iron rod. This methods are conversely very difficult due to the nature of Cast Iron as earlier mentioned.
However, from the foregoing discussion, it is clear that Mig welding Cast Iron is not only much easier but also very convenient. It is also cost effective and most used method.
The weld lasts long and has a very high quality since slag is not entrapped and the arc is protected by the gas. This stress-free process is therefore ideal for but not limited to beginners.