Cast iron is a popular material that we use for different applications. That’s why we need to deal with this material when it cracks or breaks from a cast component. So, the ultimate solution is welding it.
Welding cast iron a tricky and precision task. However, understanding the basics is the key point of welding this material. On top of that, you’ll need massive heat and expensive equipment, and the right welding method to do it.
So, we are going to discuss the stick welding method for you as a new skill step by step here.
Table of Contents
All About Cast Iron And The Importance of Welding It:
Cast iron is not a single material because it’s a blend of different numbers of material. Iron, steel, and carbon is the main material that has been used to make cast iron.
Replacing a part of cast iron can cost thousands or hundreds of dollars. To get an ultimate solution you might need to hire a cast iron welding specialist. It is not only challenging to weld but also brittle and cheap to fix.
To weld cast iron, stick welding is the preferred method and you don’t need any Oxy acetylene torch for it. Stick welding is a complex welding method.
So, it’s important to understand the reality and the difficulty to adopt stick welding to weld cast iron. Because unappropriated steps can give it more cracks in the pieces.
What Is Stick Welding?
Stick welding is one of the most common and dominating welding processes to weld cast iron. It’s a form of arc welding. You can use stick welding for effective joints and it’s very economical.
Trust me, all techniques of stick welding are difficult to learn unless you know the proper steps. Most of the time, it needs a high skill level. There are a few things you can focus on to perform stick welding to make it effective.
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Things You Need for Stick Welding:
Stick welding needs some equipment as a prerequisite. Let’s take a quick look at them.
- Electrode (Also known as rod holder)
- Power Supply stick welder (ensure constant voltage)
- Ground clamp
- Safety Equipment like welding gloves, apron, helmet, etc.
Always remember safety is the priority for stick welding. If you have everything that I mentioned earlier, then proceed with the next step.
The main point of stick welding is the use of a consumable electrode that is covered with flux. Yes, you heard right. Stick welding is one kind of metal arc welding. But electrode types are not fixed for it.
Based on the application, especially considering the material color you can change the electrode. After the match, you can start to weld.
But what types of filler professionals use for stick welding? There are three of them and these are.
- Nickel Alloy electrodes
- Copper alloy electrodes
- Cast iron covered electrodes
There are still some problems you can face. High carbon content is one of these. Because of it, the chances of cracking the material increase. Thermal control issues also play a vital role in such a result.
Remember, most of the cast iron contains 2 to 4 percent carbon. So, picking machine-friendly welds can solve this problem. So, you can pick one of these mentioned below.
- Nickel 99 soft weld
- Nickel 55 soft weld
- HTS-528 Brazing Rod.
The last one is popular because it’s one of the strongest rods to joint cast iron. But why is nickel? It’s a non-ferrous alloy. It becomes the best choice for repairing cast iron because it does not absorb carbon. That’s what you need.
The Key Steps To Weld Cast Iron With Stick Welder:
Pre Heating:
This is the first and obvious method you need to follow. Without preheating the material, there is a chance of cracking any casting. You can use a temple stick and this stick will help you to control preheating.
Preheating is necessary for controlling the cooling rate. Wait, what? Yes, it’s very much useful. To ensure the heating, you can see the temple stick is melted. That means it’s ready for welding.
Professionals adopt this method for welding some complex shapes. Complex means different thicknesses. Because it responds differently to different thicknesses. Without preheating, the material will distort. Even damage due to thermal stresses.
Clean The Casting:
If there is any surface material on the casting then remove all of them. Preparing all casting also includes cleaning different flammable elements like grease, oil, paint, and other material that are obstructive.
You also need to clean the joints that you’re going to repair. Use grinding or any kind of cleaning solvents to clean it. Sometimes you need to get back the sound metal when porosity makes a problem. For that grinding becomes a must-do option for you.
Welding:
Now start to weld. On the welding rod, there is flux (Special Graphite rich flux). This graphite plays the role to tie up the cast iron together based on the chemical reaction. But it works only in the heat-affected zone. As a result the metal weld perfectly.
Finishing:
It’s time to finish the weld. After the weld, there may be some tensile stress. If the stress reaches its highest critical point, then it’ll crack again. So, you can adopt a method called peening.
Just take a ball-peen hammer and use it against the weld. It’ll help to moderate the strike. Now slow down the cooling system of the material. Heat it periodically that also ensures a good finish.
Conclusion
Welding cast iron using a stick welding method is not an easy task even for professionals. Without proper preparation and adequate care, it’s not possible to perform stick welding.
However, stick welding makes a strong component that keeps the metal together for a longer time. This guideline that I’ve discussed step by step will help you to understand how to weld cast iron with a stick welder.
Even as a beginner, you can make a try. Don’t go for any shortcut method. The following step-by-step guide will give you better results.
