If you think that you've seen a lot of stainless steel products in recent years, then you aren't imagining things. In 2016 alone, over 45.8 million metric tons of stainless steel was produced worldwide. Right now, we're using stainless steel for everything, including jewelry, kitchenware, furniture, home appliances, building structure, and even aerospace technology. All those stainless steel products means that there is a lot of stainless steel welding happening as well - and the process is more involved than you might assume.
But aside from its pleasing aesthetics, why is stainless steel so popular? In addition to being shiny and very silver, stainless steel has excellent endurance too. Stainless steel has corrosion resistance, strength, and workability. The fact that stainless steel is so adaptable and has so many uses makes it a popular choice for welders and product designers. However, there is a downside. Because stainless steel is so adaptable, it is also ironically more difficult to weld than regular carbon steel.
That said, not all stainless steel and not all stainless steel welding methods are equal. If your goal is to create beautiful pieces of stainless steel, then it's important to know the various types of stainless steel and stainless steel welding methods. Keep scrolling for our crash course in stainless steel welding.
What Is Stainless Steel Welding?
Stainless steel welding, like any other welding, is the process of manipulating metals through high heat, sculpting, and fusion. Where stainless steel stands apart is in its distinct attribute as a non-rusting steel, and it is this attribute that makes welding stainless steel a bit more involved than welding other metals. For this reason, there is more than one kind of stainless steel and a few non-negotiable rules in the stainless steel welding process to produce a quality product.
The Basics Of Stainless Steel Welding
Overall, the actual welding part of stainless steel welding isn't so much different than welding with other metals. The real difference in techniques comes in the form of preparation of the stainless steel and the tools used during welding, the care and control necessary for heating and cooling stainless steel, and the need to properly match
filler metals with the stainless steel being welded.
When welding other metals, you might not think twice about using the same tools on different alloys. But stainless steel is not as forgiving as other metals. It is important to avoid cross-contamination from other metals, especially zinc and carbon steel. This means that none of the tools you use for stainless steel welding can have been used on galvanized steel. In particular, the brushes and hammers you use during stainless steel welding must be specifically meant for working with stainless steel and stainless steel alone.
Why would using tools on stainless steel that have been used with carbon steel be a problem? Trace amounts of carbon steel from those tools can become embedded in the stainless steel and cause it to rust. So be sure to keep all of your carbon steel welding tools--brushes, hammers, clamps, and the like--far away from all of your stainless steel welding tools if you want to keep the integrity of the stainless steel intact.
It is also important to clean stainless steel before welding. Of course the same goes for welding with other metals; but stainless steel requires absolute cleanliness so as to not compromise the alloy. Before you weld stainless steel, you need to make sure that it is spotless. All moisture must be removed. All organic containments like oil, paints, grease, and soap must also be removed before you begin.
The second most important factor in welding stainless steel is to make sure you have the right filler material. To have the right filler material, you must know the exact type of base stainless steel you are welding. Stainless steel is only friendly with same-base stainless steel filler metal. The easiest way to make sure that you are using the right filler is to use a metal with the same number as the base stainless steel. Better safe than sorry.
What Are the Most Common Applications of Stainless Steel Welding?
As we already mentioned, there are numerous applications of stainless steel welding. Stainless steel metal is used for thousands of products each year. From the smallest, daintiest stainless steel jewelry to the steel frame of boats, airplanes, and spaceships, stainless steel has a vast number of applications. But it might surprise you to learn that different types of stainless steel have different kinds of applications.
Different Types Of Stainless Steel
There are five main types of stainless steel. The most widely used is austenitic stainless steel, which is found in matching and fabrication of pipes, tubes, sheets, and other structural products. Hard martensitic stainless teel is frequently used in applications with higher ware, such as hardfacing.
Ferritic stainless steel is generally less expensive, so it is used for consumer products like automotive parts or other products that need lightweight stainless steel. Duplex stainless steel is the strongest type but also the most difficult to work with, and for that reason it is typically used in building structures and process industries.
Finally, precipitation-hardening stainless steel is a type of stainless steel that includes other alloys to increase strength, so it is used for high-performance functions, such as aerospace engineering.
What Are the Different Methods of Stainless Steel Welding?
There are many different types of stainless steel welding methods. Generally, the welding process for stainless steel varies depending on the thickness and finish of the material as well as the intended used of the finished product. In the United States, there are three methods of stainless steel welding that are most common: TIG welding, resistance welding, and MIG welding.
TIG Welding Or Gas Tungsten Arc Welding
The TIG welding method is the most commonly used stainless steel welding process. TIG welding offers high quality, versatility, and longevity. TIG welding uses a low heat input that is perfect for thin material. Depending on the needs of the specific product being created, argon gas is mixed with other gases such as helium, hydrogen, and nitrogen.
In order to prevent oxidation and increase corrosion resistance, a single-sided process can be used to create gas protection between interior and exterior welds. TIG welding is most often used with stainless steel types that are thin and lightweight.
Resistance Or Spot Welding
Resistance or “spot” welding, as it is often called, is one of the most economical types of welding. The resistance welding equipment is extremely versatile, which means it can be used on both small and large projects. Resistance welding uses the application of an electrical current to heat frayed metal edges and seal them together.
While largely a restorative and repair method, this kind of welding method can also be used for fabrication of thinner stainless steel. Restorative welding is exceptionally useful with stainless steel that has a low melting point because the method prevents a distortion of the metal overall.
MIG Welding Or Gas Metal Arc Welding
This is another form of welding that utilizes gas; which means it's perfect for highly fussy stainless steel. MIG welding is a semi-automatic process that can join two pieces of stainless steel. Using argon-rich shielding gas and a solid wire electrode, MIG welding is slightly more involved than the previous two welding methods.
However, MIG welding is popular because it allows the welding to use a pulsed current supply. This pulsed current supply makes it easier to weld tough to reach spots on complex stainless steel products or products that require the stainless steel not be overly worked to maintain structural integrity. Other gases are used
in addition to argon, such as helium, oxygen, and carbon dioxide, to improve the quality of the weld.
Stainless steel is a material growing in popularity, both because it looks nice and because this type of steel has many applications, including being strong enough to withstand high performance demands. Generally, the most common type of stainless steel used for welding is austenitic stainless steel, and the TIG welding method is the most popular way of working it. That means that the stainless steel finishes on your home appliances and furniture were probably made with this material through this method.
However, as we now know, there are different types of stainless steel: five, to be exact. Each type of stainless steel requires the same pre-welding cleaning process and the same attention to using the right filler metal so that the integrity of the steel is not compromised. It bears repeating that stainless steel is highly sensitive to contaminated tools and materials.
Additionally, stainless steel also has welding methods that are unique to the material, which means that choosing the right stainless steel welding method ultimately depends on the qualities of the stainless steel metal being worked with and the intended use of the finished product.
If you keep all of this in mind, you are well on your way to mastering stainless steel welding.