Welding cast steel correctly: how can you do this?

Because welding work is well paid, people try to learn all the principles of its implementation. This provides a good income, or you can do the work yourself, without the involvement of craftsmen. More details about the technique of welding cast steels and welding cast iron will be discussed in this article.

Features of cast steel

Before proceeding to the study of the principle of welding cast steel, you should familiarize yourself with the cast steel itself. This is a whole category of steel, which has certain properties and differs in chemical composition. Often this list includes alloy steel. However, structural steel is often used, as well as low alloy steel.

Cast steel differs from other materials in that it is molded rather than ingots. Therefore, it becomes possible to form complex shapes. You do not have to form several ingots to get a multi-faceted object.

Cast steel creation

To make a mold from cast steel, the blanks are first heated. They should melt and become liquid to better fill the mold. As soon as you move the material away from the heat source, the metal begins to harden and take on its final shape.

There are several options to preheat cast steel.

Charcoal from wood and carbon

This method is considered the oldest. This is the optimal solution for low-quality cast steel production. However, if you are using mild steel, you can increase the carbon content in it.

Electric arc furnace

This option is in great demand. The work uses electricity. However, to reduce the effect, electricity can be combined with gas.

Nitrogen

The essence of this method is that nitrogen and carbon are added to the metal so that the product is saturated with nitrogen. This allows you to improve the quality of the cast steel, while the texture remains fine and uniform.

Carbon, nitrogen, and oxygen

This method has been introduced recently. The metal is placed in a chamber with a vacuum, after which it is heated. After the introduction of nitrogen and oxygen. This ensures the purity and uniformity of the steel. There is practically no pollution in it.

What is the difference between cast iron and cast steel?

Cast iron and cast steel have significant similarities with each other. A detailed comparison of cast iron and cast steel you can read below.

Cast iron vs cast steel: chemical composition

Cast iron contains more carbon. Therefore, cast iron is less durable. Cast iron contains a high content of iron oxide. Cast steel contains more nickel, chromium, and manganese. Therefore, the material is more durable.

Cast iron vs cast steel: texture

Cast steel is smooth. It looks like it has been polished. Cast iron is quite rough and has a grainy texture.

Cast iron vs cast steel: sparks

When cutting or grinding metal, you may notice the appearance of sparks. By their nature, you can understand what material you are dealing with. Cast steel has bright and light sparks. Cast iron produces darker sparks that appear dirty.

Cast iron vs cast steel: weight

You can determine the origin of the material by weight. Cast iron is lighter than cast steel. This is because there is little carbon in the cast iron.

How to use cast steel?

The purpose of cast steel may differ from its varieties.

• Cold-finished steel. This option is often used in the manufacture of industrial equipment and tools. This is the best solution if you need to make a shovel, an ax, or parts for a vehicle.
• Lead cast steel. This version of the metal is soft, so it is often used in the manufacture of bullets. Steel is straightened in huge containers, after which it is filled with molds and allowed to cool.
• Liquid cast steel. The advantage of working with this material is that you do not have to reheat it after casting. It is somewhat more difficult to work because the material is thin and can spread. Used as filler metal in wells for oil production, pumps, or motors.
• Molten cast steel. This molten metal is of high quality. It should be noted the strength and long service life. It is used for the construction of bridges and houses.
• Stainless steel. This is the most popular reference. Often used in the manufacture of knives. Chromium is added to the metal, so it is not affected by rust. Products are very strong and durable.
• Color cast steel. It is used for laying rails on railway and tram tracks. It hardens quickly, however, cools for a long time.

Can cast steel to be welded?

If required, you can do so. The material is quite durable and resistant to heat and pressure. If you plan to weld cast steel, it is better to use the special Forney E7018 welding electrode for your weld area.

It is 5 pounds and 3/32 inches long. You can weld metal in any position.

What to consider before welding cast steel?

If you decide to go into TIG welding cast steels, it is important to consider several factors. They guarantee a quality result and your safety.

Dimensions

For beginners, it is better to pay attention to small parts made of cast steel. They are easier to weld. Even if there is a small crack, in the future it can develop into something more serious. You have to work carefully to avoid errors and deformations.

Work speed

Inexperienced people find it difficult to work with cast steel. Therefore, it is better to work carefully. Make sure that the welding container does not cool down, otherwise, cracks may form.

Safety

If you plan to weld metal, then you must have special clothing. Choose materials for stick or TIG welding that is not ignited when struck by a spark. Additionally, special protective equipment for welding cast iron or steel is required. You should always have an emergency plan in place.

Terms of service

When working with cast steel, several problems can be encountered, including high temperatures, as well as low strength at high temperatures. Given that cast steel melts at low temperatures, if you change operating conditions, cracks can form.

Working conditions

It is important to pay attention to the conditions under which welding is carried out. If the conditions are hot or cold, this can become a problem and cause unpredictable results.

It is extremely important to monitor the humidity indicators. If conditions are not correct, cast steel parts do not bond.

Distortion

Quite often, people face the problem of deformation when working with cast steel. It is important to ensure that the weather outside does not provoke problems during and after welding. To prevent deformation, follow a few tips:

1. Cool the cast steel and make it immobile using a sandbag.
2. Keep parts together when you do welding. Be aware that the clips may not guarantee the quality of the bond, which may cause cracks.
3. Allow material to acclimate to temperature changes before restarting work.
4. Use welding machines that have low heat input capacity. The wire feed welder must feed the wire at a minimum speed.
5. Use a wire that is suitable for the job.
6. Cast steel should not be turned until welding is complete.

Problems with preheating

If the temperature of the cast steel is low, this can significantly complicate the welding process. For safety reasons, you need to slightly warm the material before starting work. This is the best solution if you plan to work with thick materials.

This is because their thermal conductivity is negligible when compared with thin parts. The more carbon in the composition, the more heating is required. Only in this way will cast steel to be welded.

Varieties of cast steel

There is a large assortment of cast steel. All varieties differ in carbon content, heat treatment, and alloy composition.

Low-carbon cast steel

This variety implies a small amount of carbon. It is no more than 0.3%. Such low-carbon cast steel is softer and easier to weld. Also, this material is easier to process. However, with sudden cooling, preheat low-carbon castings can become covered with cracks.

Medium carbon steel

The composition of this variety contains 0.3-0.5% carbon. It has a harder structure and is less susceptible to wear. When cooled, it is less covered with cracks. It is the ideal material when fast processing, braze welding, and grinding are required.

High carbon cast steel

In high-carbon steel, the amount of carbon can exceed 0.5%. Therefore, high-carbon steel is more difficult to weld or process. You have to work at high temperatures to weld metal. You need to purchase special equipment that has a high amperage to weld metal.

Features of welding cast steels

If you are planning to weld cast steel, then you should pay attention to the GMAW process. If you are an experienced craftsman, you can stop at the FCAW and TIG welding/GTAW processes. They require more preparation and processing of the material in the future.

Remember that you need to be patient. Do not rush while working. After all, there is a possibility that the final product is weakened, and completely unusable. Stop doing slow work. Heat needs to be applied slowly and constantly.

This is explained by the fact that the cylinder for welding can cool quickly. If you heat the material intensively, it is hardened and does not be usable. The energy from the welding arc must be directed into the weld pool. Absorption should be slow and even.

When the welding of cast steel is completed, the seam needs to be cleaned. The process may differ, depending on which alloy you choose to work with.

Careful surface grinding

If you pre-sand well old welds and cracks, the parts hold together better. Therefore, the final seam differs in strength. It is extremely important to clean both sides. This prevents clogging.

The use of a filler in which there is little hydrogen

You need to choose the right accessory wire. This guarantees excellent seam quality. It is recommended to work with the help of a filling rod, in which there is a minimum amount of hydrogen.

Warm up if needed

If you want to work with cast steel, it’s best to preheat it. This ensures that the material reaches welding temperature more quickly. Therefore, the work process is accelerated.

Correct rod position

If you plan to weld cast steel, you need to hold the rod at the right angle. The optimal indicator is 45 degrees. This ensures the strength of the seam and the prevention of cracks and holes.

Formation of slow and stable welds

You need to use automatic robotic welding. Thanks to this, the heat supply is stable and uniform. Do not allow sudden movements, because they reduce the temperature of the alloy. Do not finish welding work until the entire seam is completed.

The filling material must be completely melted. Only in this way can you guarantee maximum strength and long service life. If excess filler metal has formed on the outside, then removal should be carried out using a grinder. This should be done after the completion of welding work.

Thorough cleaning after welding

When the welding work is completed, you can leave the material to cool completely. You can not touch the seam, so as not to get burned. Once the surface has completely cooled, you can begin to remove contaminants. To do this, use a jackhammer or wire brush.

Once you remove the debris from one part, you can start working on the rest of the parts. Remember that the debris separates easily once it has completely set. Therefore, it is better to refrain from using force. After all, you can form a dent, or deform the weld.

A few tips for welding cast steel

If you can’t give up on the idea of going into cast steel welding, then try to stick to a few basic tips. Try to use a welding machine that feeds wire with low heat input. The material must be preheated to prevent cracking.

Use correct welding rods that are made of stainless steel. Ordinary steel would be out of place. The right welding rod helps prevent warping and the finish is better. The wire feed speed may need to be adjusted. Focus on how much carbon is in the composition of the material.

Work carefully with the welding rod and this process completely. Make sure that the steel casting does not get very hot. If necessary, provide protection as well as cooling with water. If you work with thick pieces of material, the welding process requires more time and heat. As an alternative to stick weld cast steel, use TIG welding.

Stick welding does not always be appropriate. Especially if you don’t want cracks to form. Before starting TIG weld cast steel, it is recommended to study the operating instructions for the device, as well as the product, which is made of cast steel.

Security tips

There are a few safety tips to follow if you decide to get into cast steel welding. This list includes several recommendations:

1. Wear gloves and shoes that are resistant to high temperatures. You also need an apron that is fire-resistant. Additionally, prepare a mask for welding.
2. The ears need to be closed with earplugs. Put on a face mask that prevents the inhalation of dust, manganese, phosphorus, and sulfur. Indeed, during operation, it is difficult to avoid the formation of harmful fumes.
3. Before starting work, you must ensure that you do not inhale gases or particles that are emitted by cast steel.
4. Do your work in a well-ventilated room. This prevents vapors and gases from affecting your respiratory system.
5. Do not touch hot metal. It is important to give it enough time to cool completely. If you need to check the quality of the seam, then it is better to use leather gloves.

FAQ

When it comes to welding cast steel, beginners are interested in welding rod vertical, filer metal, braze welding, stick welding, etc. Much information you may read above. Let’s see about other popular questions.

Results

As you can see, welding cast steel requires certain skills and care. You must carefully monitor the materials used, the intensity of the heat supply, and the quality of the seam. If you inattentively approach the work, you risk ruining the part.

Read also: Is TIG welding hard for beginners? How to start the welding process?