Since the beginning of time, all men have wondered if you could weld cast iron to steel. The long-time myth has been that you can’t weld cast iron to anything because it is so brittle and weak.
Despite this, I attempted several times to weld cast iron to steel as well as other metals. Below is a summary of my relative experience welding cast iron to steel.
This article will explain can you weld cast iron to steel. I will cover the basics of various welding types, the different ways to weld cast iron and steel, what to expect when using them, and give a quick list of pros and cons for each type.
Can You Weld Cast Iron to Steel?
Welding cast iron to steel is possible, but you should know a few things before you try it. First, you should know that you need to use a special kind of welding rod when welding cast iron to steel. This rod is made with a lower melting point than other types of welding rods.
This means that it will melt faster than regular welding rods and will allow you to weld the two surfaces together more easily.
Another thing that you should know is that cast iron has a higher carbon content than steel, which means that it will burn hotter than regular welding rods.
If your welds become too hot, they may develop cracks later on in their life cycle due to this fact. This can lead to leaks and other issues with your finished product.
You also need to make sure that your protective gear is up-to-date when working with these materials because they can be dangerous if not handled properly or if there isn’t enough ventilation in the area where you’re working on them.
For a better understanding of welding cast iron to steel with the help of steps and precautionary measures, keep reading!
Which Factors Make Cast Iron and Steel Different?
The two most important factors that make cast iron and steel different are their chemical compositions and their properties. In contrast, there are many others that I will discuss below in detail.
Cast iron is made of carbon and iron, while steel is made of iron, oxygen, and carbon. Steel is also made of other impurities, like silicon and manganese. The carbon content of cast iron is 1.7 to 4%, while steel has 0.05 to 1.7% carbon.
Cast iron has a lower melting point than steel (about 1,500 degrees Fahrenheit), but it can be hardened and strengthened by putting it through a process called carburizing.
Steel does not need to be hardened or strengthened through a process like this because it already has good strength and hardness.
1. Content of Carbon:
The first difference between cast iron and steel is the carbon content.
Carbon steels are simple alloys made of iron and carbon. Their weldability depends on the proportion of carbon present in them:
- Less than 0.30% carbon makes steel that cannot be welded, but it can be forged.
- Less than 0.50% carbon creates low-carbon steel that can be welded with difficulty and must be heat-treated afterward to prevent cracking.
- High-carbon steel contains more than 0.6% carbon and is easy to weld, but it is susceptible to corrosion when exposed to oxygen in the air or water at room temperature.
- Extra-high-carbon steel (0.90% C or more) is rarely welded because it is so hard that it lacks sufficient ductility for welding processes such as oxyacetylene flame cutting and resistance spot welding.
Cast iron is an alloy that contains 3%-3.5% carbon, while steel contains anywhere from 1% to 2%. A small difference in the amount of carbon that makes up cast iron and steel makes a large difference in their weldability.
The addition of other elements such as silicon, manganese, and phosphorous increases the hardenability of cast iron, which means that it can be hardened by quenching after heating by itself or with other metal alloys (such as stainless steel).
Following are the four types of cast iron:
Gray cast iron – has low carbon content and a relatively high percentage of silicon. It is very soft, especially when cold, and is used for applications such as engine blocks where toughness is not an issue.
Ductile cast iron – has a high carbon content and a relatively low percentage of silicon. It is significantly stronger than gray cast iron, but it too can be very soft when cold and thus needs to be heated before use in many situations. Ductile cast iron is the most common material used for making engine blocks today.
Malleable cast iron – has a higher carbon content than ductile cast iron and less silicon than gray cast iron, but it still contains enough silicon that it can be cold-formed into shapes without cracking or breaking apart (unlike steel). This property makes it useful in applications such as gears, where its ability to be formed into complex shapes without cracking gives it an advantage over steel gears that must be forged instead of stamped into shape.
2. The Difference in Melting Points:
When you’re looking at the difference between cast iron and steel, one of the most important factors to consider is their melting points.
Cast iron melts at 2,800 degrees Fahrenheit (1,538 degrees Celsius), and steel melts at 2,500 degrees Fahrenheit (1,377 degrees Celsius).
This isn’t just a matter of temperature; the two materials have different chemical compositions as well. Cast iron has a higher carbon content than steel, which makes it more brittle than steel.
This means that it’s important for cast iron to reach its melting point before it starts to deform under pressure or stress.
3. Variation in Volume Changes:
When you heat up cast iron, it expands. When you heat up steel, it contracts. The amount of change in volume is different for each material. And this statement is true because I personally experience it in my own project.
Cast iron has a higher density than steel, so it will expand more when heated (the extra space inside the material means there’s room for expansion). Steel’s lower density means that when it heats up, the space inside the material gets smaller, and the material contracts.
The expansion and contraction of these materials under high temperatures can have an impact on their durability and performance.
4. Cast Iron has Many Impurities:
Cast iron contains many impurities, such as carbon, silicon, manganese, and aluminum. It is one of the most common materials used to make products such as pipes, tools, and machine parts because of its strength and durability.
Steel is made from iron ore that has been purified by removing all impurities except for carbon and other trace elements.
Steel is stronger than cast iron at comparable temperatures, but it is also more brittle due to its low ductility (ability to bend without breaking).
Also See: Fixing Cast Iron With JB Weld- Easy Steps
How to Weld Cast Iron to Steel?
Welding cast iron with steel is a bit tricky because of the different thermal expansion rates of the two materials. But you can easily weld cast iron to steel through the following steps along with precautionary measures:
Step 1: Recognition of both metals
If you’re going to be welding cast iron to steel, you need to know that they are two different metals. And each metal has its own properties and characteristics.
Cast iron is a very dense, hard metal made up of carbon, silicon, and small amounts of other elements such as manganese and phosphorus. It’s used in a number of applications, including machine parts, engine blocks, and cylinder heads.
Steel is a widely used alloy that contains iron (80-99%) combined with carbon (0.2-2%) or other elements such as chromium or nickel (for stainless steel). It’s much stronger than cast iron, which makes it ideal for many construction projects.
Step 2: Scrubbing of metals
To weld cast iron to steel, you need to clean both metals. The reason for this is that if there is dirt or oil on either metal, the heat of the welding will cause these substances to burn off and form carbon deposits in the weld.
This can weaken the weld and make it brittle. The best way to clean both metals is with a wire brush or abrasive cloth. Try to scrub at least 2.5cm prior to the metal joint.
I personally recommend that you can also use an acid cleaner like muriatic acid or phosphoric acid, but be sure not to leave any residue behind after washing off these chemicals because they will cause galvanic corrosion if they come in contact with any part of your equipment that is made of aluminum or copper.
Step 3: Get Ready for the joint.
Welding cast iron to steel is a little more difficult than welding steel to steel or aluminum, but it’s not impossible.
The next thing you need to do is prepare the joint. This means grinding down the welded area on both pieces of metal so that they are flat and smooth. This will allow for better penetration of the welds.
Then you’ll use an angle grinder to remove any surface rust from both pieces of metal. Take care not to overheat them, as this will cause more damage than good!
Once you’ve done this, you can start welding your joint together with a die grinder and an angle grinder.
I advise you that you should have to take practice before you get good at welding cast iron to steel; don’t be discouraged if it takes a while to get it right!
Step 4: Preheating of joints
To weld cast iron to steel, you’ll need to preheat your joint. The goal of preheating is to get the metal hot enough that when it’s hit with an arc, it’ll melt and form a bond with the metal around it.
The best way to do this is with a gas torch. You can use propane or natural gas, but make sure you have a proper regulator attached so you don’t blow off your face (or anything else).
If you don’t have access to a torch, you can use an electric heating element or even a barbecue grill.
Once you’ve heated up your joint, wait until it’s at least 500 degrees Fahrenheit before applying the welding rod.
Step 5: Use a small amount of weld to cover the joint
Cast iron is weldable to steel, but you’ll have to be careful about how you go about it.
Cast iron is relatively soft and can be easily damaged by the heat of welding and the intense sparks that fly when you weld.
So, before you begin welding, make sure that you’ve cleaned off any rust and oil from both surfaces so that they’re smooth and free of contaminants.
If you do not clean any rust or oil from the surface, then I assure you that you may face rusting issues.
You’ll also want to make sure that you have good contact between your two pieces of metal. In other words, they need to be touching each other without any gaps between them.
Once you’ve got everything set up properly, begin by welding small beads across your joint until it’s fully covered with metal.
Some useful tips to follow:
| No. | Tips to Follow |
| 1 | Cast iron and mild steel are similar in their metallurgical properties, but they react differently to heat. It’s important to recognize this fact when welding these two materials together. |
| 2 | Keep in mind that when welding cast iron to steel, you should avoid weaving at all costs. |
| 3 | Make sure the travel speed is fast because large beads cause too much heat at the base of the weld and can cause cracking. |
| 4 | You’ll need to use a short arc length. |
| 5 | Using the lowest amperage possible will also help prevent brittle cracking due to the high-stress levels in cast iron. |
Step 6: Beads peening
Peen each bead by hitting it lightly with a hammer. This will shape the weld and make it more durable since it will be harder to break. This process must be repeated until you are satisfied with the result.
For example, if you notice a ridge in the center of each bead, tap it down with a hammer until all points are even.
Step 7: Reheating of metals if needed
Before you take apart the weld joint and begin remelting, reheat the cast iron to keep it molten. This is important because if it does cool down to an unworkable temperature, you will have to start the entire process over again.
Step 8: Protection of metals for better cooling
So, the last step to follow is when working with cast iron. It is critical to insulate the area around the welding arc. Otherwise, the cast iron will crack as it cools down. Using a cold oven or heat gun are two methods for lowering cooling temperatures quickly and safely.
Based on my experience, I request you not use any other methods for better results, irrespective of these two.
Can you Weld Mild Steel to Cast Iron?
Yes, you can weld mild steel to cast iron. Both are relatively easy materials to weld and are commonly used in construction.
The main thing to consider when welding these materials is that they both have different melting points, so you’ll need to take the proper precautions when welding them together.
Mild steel has a melting point of around 2,500 degrees Fahrenheit, while cast iron melts at approximately 2,800 degrees Fahrenheit. As long as you keep your heat source between those two temperatures, you should be able to get a good weld.
I prefer you to go for an arc welding technique for mild steel, and for cast iron, you should have to go for gas tungsten arc welding.
Can you Weld Stainless Steel to Cast Iron?
Welding stainless steel to cast iron is a little tricky, but it can be done.
First, you’ll need to know what type of stainless steel you’re working with. There are a few different types: austenitic, ferritic, and martensitic.
If you don’t know which kind you have, check the packaging or call your supplier. They’ll be able to tell you based on your specifications.
Each type of stainless steel has different properties and characteristics, so it’s important to make sure that the two metals match up perfectly before you start welding them together.
Next, make sure that both pieces are clean and free of dirt and grease; otherwise, they won’t bond well together.
Then prepare them for welding by grinding down any rough edges so that they’re smooth and even with one another; this will help ensure there aren’t any gaps between the two pieces when they come together during the welding process.
Finally, apply either flux or borax powder (depending on what type of metal you’re working with) to one side of each piece prior to welding; this will help prevent corrosion from occurring during the connection process.
When welding this type of material, the main thing going for it is that it doesn’t create lots of spatter and isn’t very hard to clean up. When working with this material, you will want a good filler rod like the NiFe-CI or Ni-CI.
Do not Use Filler Metal of Stainless Steel
You can use stainless steel filler metal, but I do not recommend it.
Stainless steel filler metal is a good choice if you’re looking for a material that resists corrosion, but it has some drawbacks.
First, it is more expensive than other types of filler metal, so you’ll be paying more for your finished product.
Second, it can be difficult to work with because of its high melting point; if you try to weld with stainless steel filler metal and don’t take precautions like preheating or cooling the workpiece first, there’s a chance that the filler metal will crack or melt before it reaches its melting point and fuses with your project.
How does the Buttering Method Help to Weld Stainless Steel?
The buttering method helps to weld stainless steel by creating a smooth, even surface on the material. This will allow the metal to be joined together easily. The buttering method is a process that uses a special type of lubricant to ensure that there are no gaps or holes in your welds.
The buttering method can be used on most types of metal, including carbon steel and stainless steel. The only thing you need is a special type of lubricant called flux.
Flux is used when welding with steel because it cleans the metal’s surface so that it does not oxidize during the process. It also helps to prevent any cracks from forming in your welds.
I applied this technique to one of my welding projects in which I welded stainless steel through the buttering method, and the results were astonishing.
Best Method for Welding Cast Iron to Steel
If you’re looking for the best method for welding cast iron to steel, I advise you to go for a stick welding method.
The process of stick welding uses an electrode to melt the base metal as it’s applied to the joint. It’s a popular process because it can be done quickly and easily, but it also requires a high level of skill.
The primary reason why stick welding is best for this application is that it allows you to use a wide range of electrode sizes, which means you can choose whichever one will produce the best quality welds in your specific application.
Following are some benefits of stick welding:
| No. | Stick Welding Benefits |
| 1 | It’s easy to learn and use. It’s a simple process that can be learned quickly and easily by anyone who’s interested. |
| 2 | The equipment isn’t expensive, so it won’t break your budget. |
| 3 | It can be used in any weather condition, so you don’t have to worry about the weather affecting your work. |
| 4 | It doesn’t require a lot of special training, so if you’re on a tight budget or don’t have time for training sessions, stick welding might be your best bet. |
How Many Types of Stick Welding Rods Exists?
There are three different types of welding rods: ENiFe-CI, ENi-CI, and ENiCu. The best welding rod to weld cast iron to steel is the ENiFe-CI. Once that has been done, you have the opportunity and best option to utilize the rod named ENi-CI.
I do not recommend the common and normal welding rods for the same reason that steel rods are not: they do not produce weld metal that is ductile and has high shrinkage.
Nickel-based wire and flux covering in welding rods for cast iron offer a combination of properties that make them well-suited for welding cast iron. Following are some:
- Excellent corrosion resistance
- Excellent weldability
- High ductility, with minimal cracking
- Minimal hydrogen embrittlement
- Adequate tensile strength, even at elevated temperatures,
ENiFe-CI stands for Eutectic Nickel-Iron with Chromium added to it. This rod has a high resistance to oxidation and creep, but it’s not very ductile. It can be used in AC or DC current applications, but most often, it is used in AC current because its resistance to oxidation helps prevent arc wander from occurring.
ENi-CI stands for Eutectic Nickel-Chromium. This rod has a good balance between resistance to oxidation and ductility, making it ideal for general use. It is also an excellent choice for AC or DC current applications.
ENiCu stands for Eutectic Nickel-Copper. This rod has the highest level of resistance to oxidation among all three types mentioned above, but it also has the lowest ductility rating among ENiFe-CI and ENi-CI.
Is it Effective to Weld Cast Iron to Steel with Mild Welding Rods? Yes, you can use mild steel rods to weld cast iron. However, I suggest you not go for this.
You should use ESt rods for welding cast iron to steel. The ESt rod is designed specifically for this purpose and contains a higher amount of nickel than the common E7018, E6013, or, even worse, the E6011 rods.
The reason why you don’t want to use the common rods for this purpose is that they contain less nickel than the ESt rod and are more prone to cracking during welding.
Popular Ways to Weld Cast Iron to Steel
MIG Welding
MIG Welding is one of the most common methods for welding cast iron and steel together. The process involves using a MIG welder to apply a metal arc to the two pieces of metal being welded together. The process heats the metal, melts it, and allows it to flow into place as it cools.
The biggest advantage to using MIG welding for this purpose is that it can be done on-site without requiring any special equipment or facilities.
This makes it an ideal solution for many industrial applications where you need to repair or replace parts quickly and easily.
Another advantage of using MIG welding over other methods is that it’s relatively easy to learn how to perform this type of weld, so there’s less training required than some other processes might require.
TIG Welding
Cast iron is a very brittle material that is prone to cracking and breaking if welded improperly or in an incorrect manner.
The best way to weld cast iron to steel is by using TIG welding rods, such as the ERNiFe-CI or the ERNi-CI, which are made specifically for this purpose.
If you don’t want to use TIG welding rods, you can also use mild-steel rods, such as the ER70S-6, with some precautions: the risk of cracking is higher with these rods than it is with TIG welding rods.
Therefore, if you do use mild-steel rods for this purpose, it’s best not to use them on large pieces or pieces that will be used under stress (such as load-bearing).
Manual Metal Arc Welding
Manual Metal Arc Welding (MMAW) is a process that uses an electric arc to weld two pieces of metal together. The arc resembles lightning and is created by two different methods: carbon electrodes and tungsten electrodes.
The electrodes are connected to the power source and the workpiece by welding cables. Manual Metal Arc Welding requires a skilled welder who can control the amount of heat put into the weld area.
MMAW produces a high-quality weld, but it is not as strong as other types of welding. It can be used on cast iron, steel, aluminum, and stainless steel materials but has lower tensile strength than other processes, such as shielded metal arc welding (SMAW).
Manual Metal Arc Welding has many advantages over other processes, including easy setup and low-cost equipment requirements; no need for shielding gas; no need for preheating before welding; good penetration when using thicker metals; and it produces an attractive finish for aesthetic appearance purposes.
Is it Possible to Weld Cast Iron to Steel Without Preheating?
Cast iron and steel are the two most common materials used in the manufacturing industry, so there’s a good chance that you’ve worked with these metals before.
Cast iron is one of the strongest elements you can find on Earth, but it has one major flaw: it’s brittle. When you try to weld cast iron or steel together, they will crack if they’re not heated properly.
The problem is that heating them up too much will weaken them even more, which means they can’t handle as much pressure as they originally could.
This is where preheating comes in handy if you heat up your metal enough before welding it together; then, when you apply pressure during the welding process, your metal will be able to handle it without cracking!
Preheating helps make sure that your welds are strong enough for whatever purpose you need them for (such as joining two pieces of wood together).
How to Weld Cast Iron to Steel through Braze Welding?
Cast iron is a hard, brittle metal that is used in many industrial applications. It has a high melting point, but it does not weld well to other metals. However, if you weld cast iron to steel using braze welding, you can make an extremely strong joint.
Brazing involves melting the filler rod and filling in the gap between two pieces of metal. The filler rod must be chosen carefully so it will melt at a lower temperature than the base metal being joined.
In addition, it must have the same coefficient of thermal expansion (CTE) as both base metal pieces, or else it will crack when heated up during welding.
Steel has a higher CTE than cast iron, so you need to choose a filler rod material with a lower CTE than either of your base metals if you want your brazed joint to remain strong after heating up during welding.
Stainless steel is one option because it has a lower CTE than either cast iron or steel alone. Another option is nickel-based alloys such as Monel 400 or Inconel 625.”
How Galvanized Steel Reacts when Welding a Cast Iron?
Yes, you can weld cast iron to galvanized steel.
The best way to do this is by using a flux-cored welding wire. When you’re choosing a wire for this type of project, look for one that contains an aluminum-silicon alloy.
You’ll also want to make sure that your gas nozzle has a water-cooled tip, as well as a primary gas regulator with a pressure range between 25 and 65 psi. You’ll want to set your voltmeter on DC volts and connect it directly to the wire feeder’s output side.
When it comes time to weld, place the pipe in a vertical position so that gravity helps keep it centered during the process.
You may also need to use clamps or other devices in order to secure everything securely in place so that nothing moves or slides around while you’re working on it.
For welding galvanized steel, remove the coating at least 2 inches, which is equal to 5cm from the weld seam. Using a NiFe-CI filler metal will ensure that no residual zinc remains in your steel.
Conclusion:
So can you weld cast iron to steel? Not easily and not without the right tools. Based on my welding expertise, I recommend that If you want to weld cast iron, you’ll need a welder that uses both MIG wire and Stick welding. The MIG gives you a solid base, while the stick helps seal in the cast iron.
FAQs:
Can you weld cast and steel together?
Yes, you can weld cast and steel together. Any low-carbon steel, in fact, will make a good weld on its own. While it is not always possible to get the results that you would expect with like-kind materials, through practice, you can learn to make strong, lasting bonds.
How do you attach cast iron to steel?
If you are looking to attach cast iron to steel, the stick welding (SMAW) process is the best way to achieve an efficient and strong weld. The use of nickel welding rods in this process makes it especially efficient.
