How to MIG Welding Stainless Steel – In-Depth Guide from Beginner to Advance


Updated: 22 Nov 2023

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MIG welding is practically an easy process, but when it is used for stainless steel, you might fear it due to its expensive and complex setup. It is because you have to handle many things simultaneously, giving you corrosion-resistant, sturdy, and aesthetically pleasing results.

The MIG welding stainless steel is a very precise welding process. The welding process includes a melting electrode with shielding gas that feeds into the process of welding a joint. MIG welding with stainless steel creates a clean, smooth, and strong weld that won’t rust.

Through MIG welding, stainless steel can open an array of applications, including fabrication, joining structural components, or fixing any mechanical stuff.

After discussing the topic with experts, we now have a detailed MIG weld stainless steel guide. So, let’s hop in.

MIG Welding Stainless Steel – Explained:

what is mig welding
MIG Welding Diagram
Source: https://weldguru.com/mig-welding/

MIG welding is preferably known as Metal inert gas welding, one of the most common and easy processes of joining different metals. When you talk about stainless steel MIG welding, this refers to welding stainless steel material in specific.

The process is complex but easy; a specific wire electrode goes through a welding gun, creating an Arc that melts on the base metal, which in this case is stainless steel. At the same time, shielding gas comes to rescue the weld pool from atmospheric contamination.

The usage of MIG welding for stainless steel is an absolute choice for different industries like construction, automotive, food sector, and aerospace. It has been used in many other industries due to its corrosion resistance and structural integrity.

Welding stainless steel with MIG has a lot of different aspects, including the stainless steel types, its advantages, etc. All these things are properly explained in the article below, along with how to set up your MIG welding equipment for Stainless steel.

Advantages of MIG Welding Stainless Steel:

MIG welding offers several advantages whenever you use it with stainless steel. Some of them are given below.

Strength and Durability:

Stainless steel is widely known for its durability and strength. They not only withstand heavy loads but also resist corrosion. It is also sturdy and has long-lasting capabilities.

Aesthetic and Clean Welds:

You may experience MIG welding with other materials, which will be good, but welding with stainless steel is very clean and attractive. It has beautiful welds with minimum slag and spatter. Clean and aesthetic welds are required when looks matter the most.

Ease of Use:

MIG welding with stainless steel is preferably easy to learn for beginners. It is not only easy, but you can also learn high-quality welds within a couple of months.

Most Grades:

Of all of the other materials, stainless steel has the highest grades for welding than others. The most common to use is 304, 316, and 430.

Types of Stainless Steel:

Types of Stainless Steel, mig welding stainless steel
Types of Stainless Steel
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Stainless steel is used in almost every other industry because it has different types to choose from. All the types have different variations based on mixing it with its different alloys. Below, we define its type based on welding.

TypeWeldability
DuctilityHigh Temp
Resistance
Common
Grades
FerriticLowMediumHigh430
AusteniticHighHighHigh304, 310, 316
MartensiticLowLowLow410, 420
DuplexHighLowLow2205

Ferritic:

This steel type is commonly used in normal welding because it is cheap and low-cost. The low presence of Nickel makes it more affordable, but on the other hand, it has molybdenum and chromium, making it very durable and hard to weld compared to its other parts.

This type of stainless steel has magnetic features, and due to its low cost, it is mostly used in areas where it doesn’t give a bad look. An example includes 400, 430, and 434 series.

Austenitic:

Whenever we talk about stainless steel, we must mention austenitic because it is its most common type, which is almost used everywhere. This material is widely used in metal industries due to its durability and weldability. This type of stainless steel is known in the world of weld due to its usage and resistance against corrosion.

It is made from a mixture of Nickel, chromium, molybdenum, and sometimes manganese. Some of the common grade stainless steel are 304, 310, and 316 series.

Martensitic:

Martensitic is one of the hard and durable types of stainless steel, which also has magnetic features. It has less usage than its other parts but comes with high strength. It has chromium, a proper amount of carbon that makes it durable to heat but not durable enough for corrosion.

Unlike other types of stainless steel, this one is used for wear materials for normal or special purposes.

Duplex:

Duplex is a type of stainless steel that combines ferritic, austenitic, or other carbon alloy elements. It combines the features of both types and is usually used for normal usage. It is mainly used in the pipeline industry because of its high corrosion resistance and durable strength.

Physical Properties of Various Stainless Steel:

Following are the physical properties of the multiple Stainless Steel:

PropertyFerriticAusteniticMartensitic:Duplex
Elastic Modulus; 106 psi
GPa
28.3
195
28.3
195
29.0
200
29
200
Density; lb./in.3
g/cm3
0.28
7.8
0.29
8.0
0.28
7.8
0.28
7.8
Coeff. of Therm. Expansion: µin./in. °F
µm/m °C
5.8
10.4
9.2
16.6
5.7
10.3
6.0
10.8
Magnetic Permeability600-1,1001.02700-100095
Melting Range °F
°C
2,600-2,790
1,425-1,530
2,500-2,650
1,375-1,450
2,600-2,790
1,425-1,530
2,560-2,625
1,400-1,440
Physical Properties of Groups of Stainless Steels

Setting up MIG Welding for Stainless Steel:

Starting the MIG welding process for Stainless steel is almost the same as welding with normal steel, but you have to make a few adjustments and changes. You can do it with its old setting, but it may affect your weld with stainless steel. The detailed guide about MIG welding for stainless steel on each step is given below, so let’s get to it.

Welding Machine Selection:

MIG Welding Machine for welding material
MIG Welding Machine
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The Welding machine is essential in MIG welding and has its proper share of stainless-steel durability. There are different types of machines for MIG welding, but you should choose the one that offers different wire, voltage, and speed control offers.

The welding machine should also be capable of working with different types of shielding gasses, or at least work with which one you are planning to use, but if you don’t, then use your own MIG welding stainless steel settings. There are also expensive and cheaper machines for MIG welding, but choose the one you need according to your budget.

Welding Wire Selection:

The wire selection for your Mig welding according to stainless steel is the primary step we need to focus on because it’s arguably one of the essential steps. It would help if you chose the wire that suits the base metal on which it is intended to weld. That’s why whenever you choose a wire, you should choose according to the base alloy.

MIG welding stainless steel wire according to the proper match sometimes takes a lot of work and makes it difficult to find. A few wire types are commonly used for stainless steel and most of its welding groups. These common options are 308, 309, and 316.

You should use other welding wires if the base metal needs something other than these wires.

Shielding Gas:

MIG weld stainless steel gas is also an essential factor, which sometimes could be one gas or a mixture of two or three gasses. Using improper shielding gas can’t only affect your weld but also create different problems for you. That’s why you should consider taking your time whenever choosing shielding gas.

Usually, people use the same shielding gas for stainless steel, which they commonly use for mild steel, but you have to be careful because sometimes it might work, but other times it may cause porosity. The shielding gas blends argon and carbon dioxide, or sometimes they mix some helium.

It is also a mixture of these three gasses. So use 98% argon and 2% CO2 gas, considered the popular mixture of gases to weld thicker sections of stainless steel while using spray transfer mode.

Spray Transfer Mode example
MIG Welding Spray Transfer Mode
Source: https://weldguru.com

The two most common shielding gasses include a mixture of argon and carbon dioxide, and another one includes a mixture of tri gas, which has argon, carbon dioxide, and a little bit of helium. Carbon dioxide is one of its main components, essential for many purposes. Still, the most common one is the prevention of oxidations and ensuring high-quality stainless steel welds.

Wire Diameter and Tension:

Just like the above, the diameter of the wire tension and diameter are also important, and choosing the one that suits you can be a challenging job for the welder. The diameter and tension can be affected and rely on many things but mainly depend on the welder’s needs and the manufacturer’s recommendation.

There are different types of wire with variable diameter and tension, but most MIG welders for stainless steel choices depend upon their needs. But remember one thing: whatever diameter you choose, make sure it smoothly and consistently feeds through the gun.

Selection Welding Gun and Nozzle:

Now it’s time to select your welding gun and nozzle specifically designed for stainless steel welding. There are different guns and nozzles for welding in the market, so you make sure the gun you are getting is compatible with MIG welding, specifically with stainless steel.

While browsing for guns, also give proper attention to the material for which it is made because it will be throwing a lot of heat and pressure, which it needs to withstand.

Set the Welding Parameters:

Before welding, you must set up your welding parameters, including voltage, amperage, and wire feeder speed. You should go with the basic welding machine manual setting, but if you have your specific setting, then you can configure your welding machine according to those.

  • Amperage: For setting amperage or current output, you should match it with your wire diameter, or you can set it up with your stainless steel alloy. Normal weld uses 1 Amp to weld basic steel, but in the case of stainless steel, it requires less than that due to stainless steel heat absorption.
  • Voltage: Choosing the right setting for voltage is also important. You can either leave the voltage set by default or change it according to your wire size, which means its thickness and type.
  • Wire Feeder Speed: The wire speed of the feeder is also important to keep monitoring it. The speed of the wire feeder is important for maintaining a stable arc and proper deposition rate for stainless steel. For stainless steel, using a slightly high-speed wire feeder is advisable compared to normal steel.

Workplace Preparation:

Preparing your workplace for stainless steel welding is important, and it includes different factors, and pre-cleaning is an important one. You have to clean the workplace and the base metal by making its surface contamination-free.

It would help if you cleaned the base metal with the help of an air pump to clean the surface of any dust and other impurities. Now, use a wire brush to clean the remaining rust, paint, grease, and other leftover impurities. After removing all the stains, take a clean cloth, dip it into alcohol, and wipe all the leftover dust and debris. Now, you have clean surfaces that improve high quality.

Work Area Setup:

After cleaning the area, it’s time to arrange it properly to work correctly for your weld later on. Ensure the area is adequately ventilated and has space for adequate air circulation. The ventilated area is important for welding stainless steel because it creates bad fumes and unsafe smells.

Other than that, ensure the room or workshop has enough light, which is essential for precise stainless steel MIG welding.

Stainless Steel Welding Techniques:

how to mig weld stainless steel, mig welding joint and travel angles
Grove Weld and Fillet Weld Example
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You should have steady hands and consistent travel speed when welding stainless steel. These are some of the main parameters that separate welders from normal people. You should have a steady hand that ensures consistent and strong weld.

There are different techniques whenever you Mig weld with stainless steel, but a push technique is better than stainless steel welding. This welding method keeps the risk of contamination low by helping the shielding gasses to cover the welding pool effectively.

Other than that, you can choose and use whatever technique you like if we recommend this one because it stands out the most.

push mig welding technique, forehand welding
Push MIG Welding Technique
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Post Welding Clearing:

The base metal needs a cleaning pre-welding process. Just like that, it needs post-welding cleaning. After the stainless steel weld, there may be some tint or discolouration, which you can clean with any wire brush or wire wheel. After cleaning with a wire brush, wipe the weld with a proper cloth, which will give the final and excellent integrity of the weld.

Whire Wheel for cleaning stainless steel
Wire Wheeld is used to remove the oxide layer from metals
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Safety Measures:

Safety is paramount in everything, including welding. There are some basic safety rules and regulations that you need to follow for safety measures.

  • Always wear appropriate safety personal protective equipment (PPE), which includes safety glasses, gloves, helmets, etc.
  • Be cautious about fumes and their exposure. Ensure proper ventilation for the welding room or use respiratory protection equipment.
  • Follow the safety guidelines for safe welding practice, which is there to prevent any accidents and ensure a very secure working environment.

All of these are the detailed steps of how effectively you can set up your MIG welding on stainless steel to achieve the best quality and durable welds.

Common Challenges for MIG Welding Stainless Steel:

Just like other welding processes, MIG welding on stainless steel also faces some common issues that you need to fix or try to prevent from happening in the first place.

  • Burn Though: Burning through is one of the common issues for welding, especially whenever you weld thinner material. You must adjust your heat setting or use thinner filler wire on thinner materials to avoid it.
  • Weld Discoloration: Weld discolouration is an issue that commonly happens to stainless steel welding due to the usage of excessive heat. You can control it by controlling the heat input.
  • Porosity: A weld defect caused by unwanted gas trapped inside the welds. To prevent it from happening, you should clean your base metal and then use proper shielding gas.
  • Distortion: Distortion happens during the contraction and expansion of the welding with the base metal during its cooling cycle. It’s common in MIG welding with stainless steel. Preventing form distortion is simple: avoid expansion and contraction between welds.

FAQs:

Can you Weld Stainless Steel with MIG?

Yes, you can weld stainless steel with MIG welding and TIG welding. Stainless steel is preferable for MIG welding because it is strong, durable, heat, and corrosion-resistant.

What Kind of Gas do you Use for Stainless Steel MIG Welding?

There are three gasses, Argon, Carbon dioxide, and helium, used for stainless steel MIG welding, and it’s in the shape of a mixture. You can use an argon and carbon dioxide mixture or an argon, carbon dioxide, and helium mixture. It all depends on your needs and requirements.

Which Weld is best for Stainless Steel?

If you want high-quality welds, TIG is the welding you should use for stainless steel, but if you have aesthetics and looks, go with MIG welding.

Can you MIG Weld 304 Stainless Steel?

Yes, you can weld 304 stainless steel to a normal plan steel in both MIG and TIG welding. You can also use this 304 on other base metals through MIG welding.

Which Wire is best for MIG Welding Stainless Steel?

There are different types of stainless steel wire to choose from, depending on the base metal. But the common wire could be ER308, ER308L especially for welding with 308 stainless steels.

Conclusion:

MIG welding with stainless steel is a simple process and way easier than other welding processes and methods. Other metals and materials have pros, but more is needed when compared to Stainless steel. Welding on stainless steel has a proper process that involves equipment selection, pre-cleaning, choosing shielding gas, etc.

Welding with stainless steel also has a lot of advantages: it has good heat and corrosion resistance, and it is durable, strong, and sturdy.

In conclusion, MIG welding is the best option for welding stainless steel. I hope you understand the topic, but if you have any questions, then feel free to ask.


Abu Bakar

Abu Bakar

Hello, Abu Bakar here, the Mastermind Behind Welding Villa. Test my years of experience through my well-written blogs, where I have covered the overall experience of welding materials and shown all the aspects of Welding, their types and equipment.

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