Welding wire is something that can appear to be a very common material within most welding shops. However, welding wire can become a significant issue if a beginner uses the wrong type of welding wire. Using the wrong welding wire can make an otherwise simple task take up the entire afternoon of the welding apprentice dealing with excessive spatter, weak welds, and welding machine jams.
However, using the correct type of welding wire can make the welding process seem smooth and confidently. The type of welding wire used will impact the cleanliness of the weld and the strength of the weld. Furthermore, the type of welding wire will impact the type of metal being welded and how forgiving the welding machine allows for imperfections in the metal.
There are several varieties of welding wire that welders of all experience levels can find and use. Understanding each of these varieties of welding wire will allow a beginner welder to make sound decisions when welding a workpiece. There are several different types of welding wire available due to the fact that each of the metals react differently to heat.
Furthermore, there are different types of shielding methods for each type of welding wire. Some welding wires can tolerate rust on the metal being welded to, but others require the metal to be spotless in order to produce the high-quality welds required of certain welding tasks. Additionally, there are welding wires created for high-speed welding robots and others created for individuals to perform their repairs with the handheld welding machine.
Each of these types of welding wire have specific benefits to welders and the welding processes, and they matter to even the most experienced welder. Solid wire is the most common welding wire used in welding shops, especially those that use gas metal arc welding. Solid wire is simply a steel welding rod that is wound into a spool.
Solid wire carries the electrical current and melts during the welding process. Solid wire uses shielding gas, such as a 75/25 mixture of argon and carbon dioxide gas to create low spatter welding on mild steel. Solid wire works best on mild steel between 22 gauge and thick metal plates.
Since there is no flux in solid wire welding, there is no need to chip away at slag on the welds. This makes solid wire the best choice for those looking to weld quickly and keep their welding environments clean. However, this benefit of solid wire welding is lost if the shielding gas is lost or if the wind will displace the argon gas from the weld area when welding is being performed outdoors.
Many welding shops will have at least one spool of either 0.030-inch solid wire or 0.035-inch solid wire available. Solid wire of these thicknesses allows welders to weld thinner metals without burning through them or thicker metals without being unable to supply enough current to weld them effectively. However, solid wire welding has the disadvantage of being unable to ignore a bad joint fit-up.
Welds will have to be chased with additional welding wire added by hand to the weld bead.
Common Types of Welding Wire to Know
1. Flux-Cored Wire
Flux-cored wire was created to solve the shielding gas issues that could arise with solid wire welding. Powdered flux is packed into the center of flux-cored welding wire.
This flux releases shielding gas as the welding wire melts during use. Flux-cored welding wire allows welders to perform welding in the outdoors in the breeze or indoors in their welding shop where a gas bottle would otherwise be needed. Self-shielded flux-cored welding wire requires no shielding gas to be supplied to the welding area.
This is why this type of welding wire is common among farmers, shipyard workers, and those who use mobile welding repair trucks. The slag that solidifies on the weld created with flux-cored welding will protect the weld from rust while it is setting, and it will also help to form the weld bead. Flux-cored welding wire will create more spatters during welding than solid wire.
However, the arc of flux-cored welding wire will dig into metal that is dirty or has been painted. Solid wire will fail to weld with this type of metal, but flux-cored welding wire is tolerant of dirty metal. Furthermore, dual-shielded flux-cored welding wire uses both shielding gas and flux to provide even smoother welding on thick metals.
This welding wire combines the benefits of solid welding and self-shielded flux-cored welding wire. However, this welding wire is more costly than either of the two types of welding wire. This welding wire is used for deep penetration welding on thick structural steel where shielding gas can also be afforded.
2. Stainless Steel Welding Wire
Stainless steel welding wire has specific chemical compositions that allow the weld to have the same resistance to rust as the metal being welded. The most common types are 308L and 316L stainless steel wires. These types of wire contain more chromium and nickel but have lower levels of carbon in their composition.
The lower the carbon level, the less chance of carbide precipitation in the weld metal. Carbide precipitation can ruin the metal’s rust resistance. The stainless steel welding wire reaches higher temperatures during welding than solid wire used on mild steel.
The welding parameters must be increased for stainless steel welding wire. Additionally, stainless steel welding wire has a weld puddle that does not readily absorb into the metal, requiring a weld weave to avoid creating cold laps in the weld. Since stainless steel is rust resistant, cleanliness is more important than in welding of other metals.
Rust on the metal will ruin the rust resistance of the weld. Carbon deposits from grinding metal will create a weld that is rust prone. Thus, care must be taken with stainless steel welding.
3. Aluminum Welding Wire
Aluminum welding wire is challenging to weld due to the high conductivity of aluminum to heat. Thus, welding aluminum with aluminum wire requires the use of a spool gun to prevent the aluminum wire from buckling in a long cable. Additionally, 4043 aluminum welding wire is the most common welding wire used in aluminum welding.
However, 5356 welding wire is used for applications that require greater strength in the weld and a color match to the 5xxx series of base metals. Aluminum welding wire is 0.030 or 0.035 inch in diameter. The feed rolls and contact tip on the welding machine must be smooth and the contact tip oversized to prevent any shavings created during welding from entering the welding liner and jamming the welding machine.
Once the proper settings are established for aluminum welding, the welds created with aluminum wire require little to no cleanup.
4. Hardfacing Welding Wire
Hardfacing welding wire is used to increase the life of metal parts that are exposed to wear. The hardfacing welding wire contains additives that create chromium carbide or tungsten particles that resist wear from friction, impact, and heat.
Farmers use hardfacing wire to repair metal plow shares. Mining companies use hardfacing wire to replace metal teeth on mining buckets. Hardfacing welding wire can be used on flux-cored welding machines since the weld does not need to be as ductile as those used in the creation of structural steel joints.
Welding with hardfacing wire sacrifices the ease of machining the welded metal part but gains the benefit of extreme durability. This welding wire is used when parts are exposed to rocks or sand.
5. Nickel-Based Welding Wire
Nickel-based welding wire is used for welding problems that cannot be solved with steel welding wire. For instance, Inconel and Monel welding wire can weld other metals together, weld exhaust manifolds that reach 1800 degrees, or weld cast iron. Nickel-based welding wire costs several times more than steel welding wire. However, welds made with this wire will not crack like steel welds which would destroy the welded part within a few days of welding.
Additionally, welding with nickel-based wire has a softer arc and a sluggish weld puddle. Welding speeds must be slower with this welding wire. However, welders who gain experience with this welding wire can weld metal parts that ordinary welders are incapable of welding.
6. Copper-Coated vs Bare Welding Wire
The debate of which welding wire is best between copper-coated welding wire and bare welding wire is a long-standing one in welding shops. Copper-coated welding wire allows the weld to reach the metal faster due to the copper’s conductive properties. However, the copper can chip or flake off the welding wire and lead to weld gun clogging.
Bare welding wire does not have the copper layer so there is no risk of weld guns becoming clogged with the copper flaking off. However, bare welding wire requires higher feed tension and is more likely to rust if not stored properly. Welding shops that produce a variety of metal products will have both types of welding wire on hand to accommodate different welding jobs.
The lifespan of the welding guns contact tips is the main difference between the two types of welding wire rather than the strength of the weld. Welding wire with different metals in their composition will perform best with specific metals and will fail when used with others. Thus, understanding the different types of welding wire and their specific uses is crucial to the welding process.
Additionally, welders should experiment with welding wire on scrap metal before attempting to weld the actual workpiece. Once welders understand the behavior of welding wire with their welding machine and shielding gas, the welder will be successful in they’re metal welding projects.
