two welders working in machine shop

Stainless Steel MIG Wire: The Ultimate Guide

When you’re trying to get into stainless steel welding, there’s nothing more frustrating than the realization that you have no idea what it is you’re getting into. There are dozens of stainless steel MIG wires on the market, each with its own list of pros and cons. If you are trying to get into welding for the first time, you must understand all the different factors that can influence your overall ability to weld properly.

Stainless steel MIG wire is an essential part of any handheld welding process. If you’re trying to bond stainless steel using a handheld torch, it’s the way to go. But how can you tell a quality MIG wire from an inferior one?

How do you know how thick or thin it should be, or how to tell if a product uses tarnished materials? This guide will answer some of your questions about stainless steel MIG wire and the welding process as a whole.

What Is MIG Welding?

Metal inert gas welding refers to the joining of typically robust materials using a consumable wire that acts as both the joining material and the electrical conductor that makes the weld possible.

Many professionals in the welding industry prefer MIG welding because it is faster than other welding processes, cheaper, and easier to learn. Because of this, MIG welding is seen in various industries, including car repair, plumbing, transportation infrastructure, and general welding equipment maintenance.

MIG welding is also known as gas metal arc welding because it employs a shielding gas when welds are being laid down, protecting the arc and the weld itself. The shielding gas used is usually an argon-helium mixture and carbon dioxide.


steel sheets stacked in a pile

What Equipment Is Necessary for MIG Welding?

The equipment that MIG welding requires isn’t too extensive, but welders must only acquire the highest quality equipment. While traditional welding equipment will last a long time if properly maintained, it must be in tip-top shape when first bought. The welder's safety is paramount when undergoing any kind of welding, so premium equipment and tools are a must for any serious welding operation.

In addition to a well-constructed welding gun, a DC power source, and a functioning cooling unit, a MIG welder needs a wire feed unit to apply the stainless steel MIG wire to the weld effectively.

This wire is an essential part of the MIG welding process, as it is effectively the glue that will bind the two metal pieces together in your weld. If you end up going with a cheap stainless steel wire, you’ll end up with a cheap stainless steel welding job.

Welding Stainless Steel

If you’re just getting into the welding arena, you might wonder how you can even successfully implement stainless steel MIG wire into the process. After all, stainless steel is a metal that is notorious for not welding easily. We’ll be breaking down why that is shortly.

In the meantime, let’s get into welding stainless steel and how you should go about it. By understanding the entire process, you’ll better differentiate quality stainless steel MIG wire from lesser quality stuff.

About Stainless Steel

While mild steel is easy to weld thanks to its high amount of iron and easy submission to the heating process, stainless steel is a different beast. While it’s theoretically easy enough to weld stainless steel, there is a significant problem with it as a material.

You see, once it is heated, certain types of stainless steel are prone to warping, stretching, and bending. This means that stainless steel can bring with it all kinds of issues for a first-time welder.

This is one reason why using the right kind of stainless steel MIG wire is paramount to your welding success – if you need to heat your joining wire for too long, you face a higher risk that your stainless steel might warp.

There are a few types of stainless steel in the world, and not all of them are ideal for welding. The most commonly-used variety is called austenitic. This type of stainless steel is flexible, strong, and highly versatile. It is an excellent pick for just about any welding, as it is easy to utilize and mold to your needs.

The other type of stainless steel often used in welding scenarios is duplex stainless steel, a mix of austenitic and ferritic stainless steel. Ferritic stainless steel isn’t a great contender for welding because it can be pretty rigid and not bond easily to other surfaces due to its low nickel content and magnetic nature.

Different types of stainless steel have different numbers that represent their meaning. For instance, you might’ve heard of 18/10 or 18/8 stainless steel. These numbers are fairly simple: they represent the percentage of chrome and nickel present in the mix. It’s easy to forget that while it’s called stainless steel, it’s still an alloy. R

egular steel doesn't have the corrosion resistance of stainless steel – hence the “stainless” title. For reference, 18/8 steel contains 18% chrome and 8% nickel, with the rest being pure steel.

There are other numbers as well that mainly apply to austenitic steel. These are 304, 308, and 316. The most popular of these is 304 – a type of stainless steel that is highly versatile and considered to be of near-perfect composition. It is used in aerospace projects and other matters of high security and functionality.

The next highest is 308, which is nearly identical to 304 but considered to be a bit harder to manage due to a slightly higher nickel content. Finally, there’s 316 stainless steel, which is unique because it is more resistant to salt water than other kinds of stainless steel out there. It is also sometimes referred to as surgical steel because it used to be used in medical equipment.

It is worth noting that there are other types of stainless steel on the market, but the 300 series, as the above three types are known, is by far the most common in consumer and professional welding projects. Most people in the world will only interact with the 300 series if they’re working with raw stainless steel.

stainless steel tubes and pipes of varying shapes and sizes stacked together

Choosing the Optimal MIG Wire

When you sit down to do a welding job, you always want to be sure that the equipment you’re using is the best you can get your hands on. While an insignificant part of many other kinds of jobs, in MIG welding, the chosen wire is of the utmost importance.

It will essentially be the glue that binds whatever you’re trying to weld together. If you’re sealing a pipe to your septic tank, then we can be sure that you’re going to want that steel to hold tight and never budge. Well, the correct MIG wire can make all the difference there – and the same goes for the wrong one.

The most important rule to follow when selecting your stainless steel MIG wire is to ensure it matches the alloy you are welding. That means if you are welding 316 stainless steel, you should use a 316 stainless steel wire. You can mix and match as needs arise, but it’s a good general rule if you’re looking for the most solid job possible.

When you mix and match different kinds of stainless steel, you’ll want to use a higher alloy. For example, if you’re welding 308 stainless steel, you won’t want to use a 304 MIG wire. Make sure those numbers only go up.

Set the Wire Amperage Correctly

When you get down to welding, figuring out what your amperage speed should be is tough. This is especially true when it comes to steel. As we said before, steel is tricky to weld, partially because there are so many different kinds of it. Stainless steel, for instance, retains heat better than mild steel, meaning you might be able to get away with a lower amperage output.

But this can also depend on the other equipment you use. When you’re trying to weld with a new stainless steel MIG wire that you might not be familiar with, we’d encourage you to start at a low amperage and work your way up as needed. Once you do this, you might have an easier time achieving optimal weld puddle fluidity.

Is That All There Is to Know About Stainless Steel MIG Wires?

Welding is a tricky science for many people, but it doesn’t have to be completely off-putting. It’s difficult, but that doesn’t mean that every one of its components is totally confusing and impossible to explain. Stainless steel MIG wires are an essential part of the welding process, and it’s crucial that you get the right kind and understand what you’re buying.

However, once you match the numbers, that’s all you really have to worry about. Other pieces of equipment are far more important to the welding process, so don’t stress too much when it comes down to the wire.

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