best metals for welding

Best Metals for Welding

The best metals for welding depend on the project design and budget, the skill and experience of the welder, and the welding process to be used. Almost any metal can be welded, but some are easier than others for creating a high-quality, defect-free weld.

Some types of metal require special equipment, such as a vacuum or gas chamber, limits on heat exposure, or pre- and post-welding heat treatment. Some perform better with different types of welding, whether stick, TIG, or MIG. Choosing the right electrode and filler material for the base metal and following prescribed welding procedures is essential. Each specific situation depends on the base metal’s chemical makeup.

Low Carbon Steel

Also known as mild steel, low carbon steel contains a very small percentage of carbon (less than 0.3%) and up to about 0.4% manganese (AISI 1018 steel). This commonly used steel is very ductile, due to its low carbon content. High ductility means high weldability because it reduces the chance of brittleness in the heat affected zone (HAZ), which can lead to hydrogen cracking. Low carbon steel can be welded using almost any type of equipment and is one of the best metals for welding.

Stainless Steel

Stainless steel can be quite weldable, depending on the grade. Ferritic and austenitic stainless steels can be welded fairly easily, but not martensitic stainless types, which tend to crack. Stainless steel tends to warp under high heat, which can affect the shape and strength of the final workpiece. Another issue is that the chromium in stainless will combine with carbon during the welding process, leaving the piece more susceptible to rust without its chromium oxide protective layer. To prevent this problem, don’t heat the workpiece above the recommended temperature, or choose a low-carbon stainless grade.

Aluminum

Creating a defect-free weld in aluminum is different than welding steel, but can be done by following the prescribed guidelines. Choosing the proper grade is important, as some types are much easier than others to weld. Because of aluminum’s high thermal conductivity, heat is transferred away from the weld very quickly. Equipment with a higher welding current may be required to supply the necessary heat. As it cools, aluminum shrinks significantly more than steel, so special care must be taken to prevent craters and cracking. Finally, the natural aluminum oxide coating on the base metal can add contaminants, and should be removed prior to welding to avoid porosity in the weld.

Other Metal Types

Other metals, including magnesium, copper, cast iron, titanium and superalloys such as Inconel, can be welded. These will typically require special equipment and expert skill, making them less weldable for traditional job shops and hobbyists.

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Which Metals Can Be Welded and Why?

Weldability is everything. Metals with a high weldability are easier to weld and retain a higher weld quality than other metals, so it’s important to study these factors before choosing materials for a project.

Once you’ve narrowed down your selection to a few metals, the next step is to determine which welding process you’d like to use. Some methods require more skill than others, such as TIG welding — and these will affect which metals are at your disposal. For example, the ideal metals for MIG welding are carbon steel, stainless steel, and aluminum, all for different reasons.

The main parameters that determine a metal’s weldability include the electrode material, cooling rate, shielding gases, and welding speed. Every metal is unique. To a certain extent, all metals can be welded, but there are clear advantages and disadvantages to each.

Stick welding, also known as shielded metal arc welding (SMAW), is one of the most common welding methods out there. To get started, you’ll need a welding machine, a proper electrode (we recommend DCEP for DC welding), a safety helmet, clamps to hold the joints together, and your welding metal of choice. With this method, you are melting a metal rod with a special flux coating that prevents oxygen contamination — hence the “shielded metal” name. Stick welding can be used to weld steel, iron, aluminum, copper, and nickel.

Unlike stick welding, gas metal arc welding (or GMAW) does not have a coating over the electrode rod. Instead, the welding gun disperses a shielding gas that protects against contaminants. It’s the most common industrial welding process today, and can be used for steel, cast iron, magnesium, and many other metals.

Ultimately, there is no clear-cut answer when deciding which metals and welding methods to use. It’s best to figure out which metals are best suited (and most cost-effective) for your project, and then decide on a welding style that can be performed with your skill set.


Types of Welding

Arc welding has a number of distinct styles, each with its own approach to binding multiple metals together via a metal electrode. Below, we’ve showcased four of the most popular welding methods, with their unique advantages and disadvantages.

MIG

Invented in the 1940s for welding non-ferrous materials, MIG used to stand for “metal inert gas”, because the welding gun would disperse an inert gas to prevent atmosphere contamination. Today, the process has incorporated carbon dioxide instead of inert gas, so it is officially known as gas metal arc welding (or GMAW). Many people still call it MIG, however. MIG welders can use globular, short-circuiting, spray, and pulse-spray methods to create an electric arc between their electrode wire and multiple metal joints. It’s the most common industrial welding process today, though it is not recommended for outdoor use (due to unpredictable air).

TIG

Tungsten inert gas (TIG) welding is a more difficult process to master, but it gives the user more power and control over the final weld. Instead of wielding a metal alloy electrode, this method uses a non-consumable tungsten version with an inert shielding gas. Depending on the weld being performed, a filler metal may also be used. TIG requires serious coordination with both hands, so it’s not recommended for beginner welders.

Flux

Next, flux-cored arc welding (FCAW) harnesses a continuously fed electrode tube with a cleaning agent (called a flux) and a constant power supply. Typically, the flux provides enough protection from atmospheric contamination, but sometimes an additional shielding gas is used. The main advantage over other arc welding methods is the elimination of stick electrodes, which makes welding faster and more portable.

Stick

Finally, shielded metal arc welding (SMAW, or stick) is an extremely popular method for construction and repairs. Coated with a flux, an electrode rod is melted to form an electric arc between multiple metal pieces. As the electrode is used, the flux changes into shielding vapor and slag, both of which serve as protection against contaminants. Stick welding requires less equipment than many other welding methods, and is excellent for stainless steel and iron.