How to MIG weld stainless steel

Do you believe that you can weld any material on earth?

Impossible, right?

You know that welding is only done on metals and even plastics. But what you probably don’t know is that this is easier said than done. It may seem all the same to you. It has different types, each more suitable for specific materials than others.

This is also the case for fusing metals with an engine-driven welder. Contrary to popular belief, you cannot simply fuse any metal using any type you want. Each metal has unique properties that can either be easy or difficult to work on.

Among the many metals around, stainless steel is one of the most notorious materials. Many don’t even know if this is possible. But can you do it? And if so, how do you do it?

All those questions will be answered if you continue reading. Not only that, but you will also discover which of the most popular types around is best. Namely, we’ll take a look at MIG and TIG. Which is more suitable for it? You’ll know all the right steps to start your MIG welding stainless steel journey by the end of this article.

Summary

Welding of stainless steel can be done but only with welding machines involving electric arcs. TIG is the most common and suitable method of welding for thin metals. It is neat but expensive. MIG is a suitable method for thick metals. It is messy but cost-effective.

As we tested various welding machines, the best one is Weldpro 200 Amp.

Other topics covered in this article are :

  • The advantages of choosing the right type of equipment for the job
  •  How to perform welding of stainless steel
  •  Different products available

Continue reading..

Table of Contents

stainless steel

Can You Weld Stainless Steel?

Yes, you most definitely can MIG & TIG weld stainless steel.

Doing so is not that different compared to working on other metals. But admittedly, its unique characteristics make it a little complicated to do so. This is because it has certain requirements for heating and cooling that other metals do not need. The filler material must always be appropriate to the type of stainless steel being worked on.

And because there are also different types, you need to work on them differently. Each type has characteristics that you need to note if you want a quality result.

Welding stainless steel is doable, but it is not as straightforward as working on other metals.

TIGMIG
SpeedSlowerFaster
The finishNeaterMessier
Who is it great for?AdvancedBeginners
DiscolorationMore likelyLess likely
MaterialsThinnerThicker
Cost effectivenessLessMore

How to MIG weld stainless steel

Because of their physical characteristics, not all types can be used. Only those involving an electric arc can be used, which include Stick or shielded metal arc. This includes MIG or gas metal arc and TIG or gas tungsten arc.

Despite having three options to choose from, fusing the material depends on its type. It is classified into three distinct types and combinations of these types. Each of them has unique characteristics that will affect their ability to be welded easily. Here’s how to MIG & TIG weld stainless steel.

  • Austenitic – Preheating and post-heating are unnecessary, but they have a maximum interpass temperature. It means you must pause when the base metal reaches this temperature and allow it to cool down first before you continue. Fast welding at high travel is needed to avoid any distortions on the material. Low current is often sufficient for this type.
  • Martensitic – the chromium and carbon content present in this type are balanced, and this affects its hardening capacity. Most of the stainless steel under this category requires preheating and post-heating before letting it slowly cool. The heat applied must be consistent as you fuse and must meet the minimum interpass temperature.
  • Ferritic – a single pass is sufficient, but the process negatively affects the resulting work. You need to quench it with either water or air afterward to improve its quality. Thicker materials only need low heat to avoid grain coarsening, which leads to cracks in the joints.

A duplex type also exists, a combination of austenitic and ferritic. It has the characteristics of both ferrite and austenite. You only need to ensure that the heat applied is within its heat input range.

In general, you need to observe the following:

  1. Wear personal protective equipment (PPE). This not only applies when you start working. You also need to wear them even while preparing the material and as you do any necessary post-heating. Toxic fumes and sparks are produced, and you need to be protected against them. You must also ensure that you work in an area without any flammable items nearby.
  2. Prepare – Because it is a delicate material, there should be no room for error if you want a flaw-free finish. You need to prepare not just the material itself but also your workspace. Plan ahead, especially in terms of what kind of joint you will be using and how you will do the actual work.
  3. Practice on other pieces first – There is no way to undo your work, so any mistakes you make on stainless steel will be glaringly obvious. Practice on spare pieces of material first to get the feel of it. The more you practice, the less the chances of committing errors.
  4. Follow proper practices – Make sure that you follow the right procedures of your chosen method. Not only that, keep the material in place to prevent scratching it as you weld. If you need to, use a clamp or any other mechanism. Always keep a close eye on your work because it is easy to damage or discolor this metal.

Fusing it may be a bit more complicated, but it doesn’t mean you can’t do it. Even if you are just a novice right now, you can work on stainless steel. You need to learn and understand how to do it properly.

Weldpro 200 Amp

Here’s our overall recommendation in terms of the best welder for stainless steel.

Name200 Amp Inverter Multi Process Welder
BrandWeldpro
FeatureMig/Tig/Arc Stick
Item Weight‎30.4 pounds
Product Dimensions‎17.72 x 8.66 x 14.96 inches
Warranty3 years

Pros

  • It’s capable of whatever method you want to use.
  • It’s a really good welder, not just for the price.
  • The flow meter, spool gun, and other devices or of great quality.

Cons

  • It’s a Chinese brand.
  • Its MIG device is better than the TIG.
  • You’ll want the ability to adjust voltage and wire feed speed independently.
Weldpro 200 Amp 
It's a great option.

MIG

If welding stainless steel involves thick materials, MIG is most suitable. This is the preferred method for those who prioritize cost-effectiveness over the neatness of the work.

This type allows you to work quickly, but the specific settings required will depend on the MIG welder you are using. This is because different machines have different recommendations. It’s specifically regarding the:

  • wire used
  • the feed rate
  • and the power supply.

You’ll also need to consider the shielding gas and electrode size. That should at least get you started if you’re curious! This information is usually found on the chart that the equipment comes with.

Different modes of metal transfer can be used, which are:

  • Spray Transfer – The electrode metal is transferred via a voltage electric arc to create a weld line with a clean finish. This method includes pulse spray transfer, wherein the pulsing current melts the electrode. When that happens, the molten material falls onto the workpiece.
  • Globular Metal Transfer – A large blob or molten globule forms at the electrode tip and eventually drops to the workpiece.
  • Short-Circuit Transfer – The gap between the workpiece and the electrode is filled with filler material. This happens when there is a slow feed rate that results in a short circuit that momentarily extinguishes the arc.

Aside from that, you also need to choose the proper shielding gas to use. Different manufacturers are in consensus that pure inert gases are not recommended. That is why the shielding gas used is typically a mix of different gases, with the tri-mix gas being used most often.

Ensure that a brace is present to hold the material in place. You must evenly spread out the heat. These two are vital to avoiding joint distortions on stainless steel, a common issue with MIG.

MIG welding on stainless steel is commonly used for repair and maintenance works.

TIG

TIG is the most popular type for working with stainless steel. Ideal for thin materials, this is preferred by many pros because it results in a neater finish than MIG. Unfortunately, this method may not be suitable for inexperienced craftsmen that have yet to master it.

Note that the clean finish it produces is because of the slower speeds involved, requiring proper techniques. This distortion is more easily preventable because of the careful method involved. But no matter which equipment you use, what is important is to have the right speed and shielding gas. Make sure the right heat is applied. Like other metals, you also need to make sure that your chosen tungsten electrode is sharp.

Discoloration is also common when using TIG on this type of metal, especially when too much heat is applied. To avoid it, you should use only the right amount of heat. You need to keep an eye out for the color of the metal. Once it starts changing color, it is too hot and must be cooled down first before continuing.

Experienced craftsmen suggest using the DCEN or DC electrode negative setting. Have a current with a ratio of 1 amp for every 1/1000-inch thickness of the metal. You may consider going down to 2/3 of one amp for every 1/1000-inch thickness. Argon is ideal shielding gas because it prevents a reaction between the molten material and air. But if you are automating the work, you can use a mix of argon and other gases.

Side note: You can make the math easier by realizing you require roughly 40 amps per mm thickness when it comes to this type of metal.

 

stainless steel being welded

Is it difficult to do?

Are you now wondering how difficult it is to work on this type of metal?

It can be challenging for most beginners, especially because of its heat-retention properties. If too much heat is applied, this metal tends to warp or become distorted as it cools down. To avoid this, controlling the heat is important. And if you have yet to master heat control when doing the work, don’t be surprised to see warping on your workpiece.

Stainless steel is renowned for its finish, a nightmare for those who want a flawless finish. This material gets scratched easily, and any scratch or physical flaw present will be immediately visible. So if you want a smooth finish, you need to observe proper practices at all times. It starts with preparation and goes on until you finish.

Not only that, it is more difficult to fuse than other metals. Its higher electrical resistance, heat expansion, lower heat conductivity, and melting temperature cause this feature. When working, you need to keep all of these in mind. Sadly, this is easier said than done.

Stainless Steel to Mild Steel

Fusing dissimilar metals is a common practice in various industries. It helps them save money and meet certain requirements that only such metals will meet. This is also the case for welding stainless steel, particularly mild steel.

Both MIG and TIG can be used to join these two metals. You can follow the usual procedures with these two methods. Still, what matters more is that you use the right filler material. The 309L filler material is the most suitable.

Some people frown upon fusing it to mild steel or completely discouraging it. The resulting work is often inferior to the one produced when using the same metals. Not only that, but you also need to prepare them separately before starting. Heat also affects them differently, making the entire process much more complicated. This combination of metals can also affect the overall corrosion resistance of both metals.

Simply put, it is doable. It is a complicated process, and the resulting bond is often brittle compared to the joint between the same metals.

When fusing stainless steel to the same or different metal and using whatever method you choose, prep work is vital. Ensure the surface of the metal is free from any contaminants. Practice working on other workpieces, so you have a clear plan on how you should go about it.

There is no room for error if you want a clean finish.

Choosing the right type of equipment for the job

welder

Whether you are a professional traveling a great distance, the right welder will allow you to be a lot more efficient at work. It will allow you to earn a significantly larger amount of money. 

The right welder will allow you to fuse the metals if you are trying to do it easily. There are definite machines that are better than others for those purposes, too. 

Whether you choose to use MIG or TIG for the job, make sure that you use a piece of machinery capable of doing the job. However, you should also know the different types of results that stem from the different processes you may be interested in.

Stainless steel is a metal that retains heat fairly well and is more difficult to work as a consequence. It’s especially the case for beginners. Make sure you are prepared for the things up ahead, as you will otherwise end up warping the steel. Suppose you are looking to get some high-quality welds. You must know the different pros and cons of various welding methods. TIG is better for precision work, which is highly beneficial when working on these types of metal. In contrast, you may be able to get the job done a bit faster if you choose to go the MIG route. If the job requires that you get a very clean result, we can only urge you to continue pursuing getting the job done with TIG!

Figure out what type you are looking for in the process. Make sure you find a TIG welder with all the various factors you are looking for. The duty cycle and the amps that it can output are very important. Otherwise, you will quickly find yourself getting tired. 

Suppose you are looking at welding something thin like 1/16” stainless steel. You don’t need that much power. You won’t need more than roughly 45 amps to get the job done. When you start increasing the thickness of the material, you will need a more powerful machine. If you are experienced, consider increasing the number of amps as you have the experience level allowing you to do so. You will want a more powerful welder. 

When you start welding stainless steel, you don’t want to be left with something that would otherwise take you forever. A good rule of thumb is that it shouldn’t take you more than 2 seconds before the puddle starts forming. At this point, you can keep repeating the process.

Certain machines are really popular if you are looking to get into them. One example is the Miller Bobcat 250. Miller Welds isn’t just a reliable company. They also produce some of those higher-end machines that can come in extremely handy. 

NameMiller Bobcat 250
EngineKohler CH 23, 23 HP at 3,600 RPM
Fuel Capacity12 gallon
MaterialsAluminum, stainless steel, mild steel
MethodsMIG/TIG/Stick
Weight32 lbs
Welding Amperage RangeCC/AC Stick/TIG: 40 – 250 Amps

worker at construction site

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