Sometimes called cold pressure welding, cold welding is the solid-state welding process of joining two or more metals together using pressurized energy (instead of heat) to create the joint. Cold welding can be used in a variety of industries, including aerospace, automotive, electronics, manufacturing, and more.
Read further to learn more about the cold welding process, and find welding training near you today!
How Does Cold Welding Work?
Unlike the more well-known forms of welding where heat is used to create a molten liquid that eventually joins the metals, cold welding works by using pressure.
Before you can perform a cold weld, the oxide layers on the surfaces of both metals must be removed. The oxide layer normally found on metals prevents metal atoms from bonding with each other. Removing this oxide layer allows cold pressure welding to take place since the atoms on both metals are now able to bond with one another. Oxide layers are typically removed with a wire brush or by other chemical/mechanical techniques.
Once the metal is stripped of its oxide layer, industrial machinery is used to create pressure strong enough to bond the two metals together. With enough pressure, the stripped metals’ atoms bond to form a joint weld.
What is Cold Welding Used For?
Cold welding works best on metals that are ductile, meaning they can be welded together without fracturing. Metals should also be clean and flat for a strong cold weld. It is important to note that any metals containing carbon cannot be used for cold welding.
Metals that are typically used in cold welding are:
- Aluminum (including 7XXX alloys)
- 70/30 Brass alloys
- Silver/silver alloys
Cold welding can be used for quick but strong joins in wires, and joining dissimilar metals with one another. It can create dependable butt joints or lap joints. Common industries cold welds are used in are the aerospace, manufacturing, or automotive industries.
Often, cold welding can be used to join wires together, particularly aluminum or copper wires. Wirework is helpful in the above mentioned industries, but transfers its use in other industries, like electrical. The process of cold welding wires is commonly used when laying wirelines underground where heat would be hazardous to use.
Cold welding techniques are also useful in electronics manufacturing when working with semiconductor devices that are sensitive to heat.
Advantages of Cold Welding
- The ability to join two dissimilar metals is a huge advantage of cold welding, along with wires of different diameters.
- No HAZ (heat affected zone): without a HAZ the risk of any mechanical or chemical changes occurring in the base metals is reduced significantly.
- When done correctly, cold welds produce sturdy bonds that are at least as strong as the weakest of the parent metals.
- Without the need of molten metal, any risk of brittle intermetallic pieces found at the joints is reduced.
Limitations of Cold Welding
- It can be difficult to get the metal clean enough to form a strong cold weld.
- Any irregularities found on the surfaces of metals can make it difficult (or impossible) to join them together; metals for cold welding must be flat for the weld to be strong.
- Since metals must be ductile and carbon free, there are some limitations as to what metals can be used.
Try Your Hand at Cold Welding
If done properly, cold welding can produce strong and quality welds in a variety of industries. To perform cold welding professionally, you will first need to apply to a welding school near you if you have not already done so.
Once you have experience working with core welding processes, you can discuss cold welding techniques with your instructor to get more information about practicing cold welding.
For further information about welding training programs, check out How Much Does Welding School Cost?