MIG welding might be used with stainless steel, but the material does warp easily. To perform the best job possible, you want to know how to MIG weld stainless steel correctly.
Just like you need the best welder to get the job done, our guide is meant to help both beginners and experienced welders learn new tricks when working with stainless steel.
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MIG Welding Basics
MIG welding uses an arc welding process allowing the continuous solid wire electrode to be fed into a welding gun where it turns into a pool. This material joins base materials together. To protect the pool from any contamination, a shielding gas is utilized.
MIG welding can be done with a variety of materials, from stainless steel to aluminum and alloys. However, there are some times when using a TIG welder is a better option.
The Properties Of Stainless Steel
Stainless steel is used across many applications because of its desirable properties. The chromium content makes it corrosion-resistant, plus it provides plenty of durability and strength. Because it has formable properties, it’s simple to fabricate and low maintenance to work with. Once stainless steel is welded, there’s no reason to treat or paint it.
Stainless Steel MIG Welding Setup & Tips for Beginners
MIG Welding Settings for Stainless Steel
Once you have the best MIG welder for beginners, you want to ensure you use the appropriate settings. You must adjust these based on the thickness of the material you are using. For example, 18 gauge stainless steel requires .035 at 120-150 IPM, 20 volts, and 50-60 amps.
Gather Welding Tools and Supplies
Before you can create a clean weld, the material must be free from grease, oil, dust, and dirt. Use a metal brush to clean the material of any contaminants.
Choose wire and shielding gas
Most jobs are going to require .030-inch diameter stainless steel welding wire, but you might need to increase this with thicker pieces. Ideally, you would choose shielding gas measuring 90 percent helium, 7.5 percent argon, and 2.5 percent carbon dioxide.
3 Choices of Transfer for MIG Welding Stainless Steel
Spray arc welding transfers metal from the electrode to the weld. Small molten droplets travel across the arc to the base metal or joint. This process works best on thick metals.
Short circuit transfer relies on lower voltage. This process occurs when the wire contacts the metal, thereby creating short circuits. The wire contacting the metal heats up to melt into a joint.
The pulsed-arc transfer or pulsed GMAW uses an alternating high peak current with a low background current. During the switch, the current creates a droplet of wire, which can be propelled to the weld joint.
How To MIG Weld Stainless Steel: Basic Tips & Tricks
Bracing the Weld joint
Put your stainless steel over a table and hold it securely with a clamp. Otherwise, you can place a plank between the joints to keep them apart. If you plan to work on large projects, you will need more bracing. In fact, larger materials might require TIG welding instead.
Spreading Out the Heat
To spread out the heat while learning how to weld stainless steel with a MIG, you want to pull the weld and allow your joint to cool before proceeding. Stainless steel can heat up quickly, allowing you to hold the MIG welding machine for longer periods than if you were working with carbon steel.
How to MIG weld stainless steel exhaust
First, you want to know how to set up a MIG welder for stainless steel. It’s also important to weld the stainless steel exhaust with matching filler metal. Don’t use the low-cost carbon steel MIG wire. Clean the inside of the exhaust with a wire brush and the outside with a rolled abrasive. From here, you can purge the inside of the exhaust by putting vent holes at the top and letting it fill with argon. We recommend allowing it to purge for several minutes before you start welding. Many materials will require an amperage of around 75, but you need to determine what’s best based on the stainless steel you are using.
How to MIG weld stainless steel tubing
Just like welding exhaust, working with tubing provides a challenge because you must purge the inside of the pipe. You must purge the pipe with argon, which prevents oxidation of the weld. If you perform it correctly, it will look like the weld occurred from the inside, similar to a wedding band shape. Just make sure there is a large enough vent hole at the top most point of your tubing so when the weld is sealed completely, the pressure doesn’t build up and blow a hole in your material or create concavity.
How to MIG weld stainless steel to mild steel
You can learn how to weld stainless steel to mild steel with MIG. You will use the same basic techniques with your welding while paying close attention to the protection you offer your workpiece. You don’t want to get stray specks of welding spatter sticking to the steel, which commonly happens. These can also lead to rust specks, so consider using a piece of cardboard to give the spatter something to bounce off of. You might also consider practicing on some scrap material before performing the actual job.
Common Challenges When MIG Welding Stainless Steel
Weld contamination or porosity reveals trapped gas. When the shielding gas is released from the molten metal before solidification occurs, it can create this unsightly event.
Improper weld bead profile
The weld bead profile is dependent on many factors, including amperage settings, travel speed, and voltage. If it doesn't look right, you need to adjust these settings.
Lack of fusion
When the wire feed speed or voltage is set too low, or if you are traveling too fast, you can create a lack of fusion, although this tends to happen more frequently with aluminum than with stainless steel.
Faulty wire delivery related to equipment set-up and maintenance
Everything must be in optimal order to create the weld you are looking for. Look over your machine and try it out on some scrap metal before starting any new job.
MIG Welding Safety Precautions
Before you learn how to weld stainless steel with a MIG welder, you want to take some safety precautions. First, check all of your equipment before starting. We also recommend reading through the owner’s manual to gain an understanding of the operation. Ensure your work area is well-lit and well-ventilated. You also want to wear protective gear that keeps your hair, body and clothing protected. Don’t weld if you are tired. To perform a solid weld, you must be in optimal condition and completely focused on the task at hand.
People Also Ask (FAQs)
What is the correct shielding gas for MIG welding stainless steel?
You want to use a mixture including 90% helium, 7.5% argon, and 2.5% carbon dioxide. Helium's high thermal conductivity provides a flatter weld bead and superior fusion.
What wire do I use to weld stainless steel?
Most jobs require .030-inch diameter stainless steel welding wire, but thick materials might need something larger.
Can you weld stainless steel to steel?
You can weld stainless steel to steel materials, but the process is more demanding and often requires additional expertise.
Can you MIG weld stainless steel without gas?
No, you need some form of shielding gas or flux to protect the weld.
What MIG Flow Rate Should be Used when welding stainless steel?
You can use a MIG flow rate chart to determine what’s best with your machine and materials.
What causes excessive spatter in MIG welding?
Spatter is often caused by one of five issues – incorrect parameters, user error, an erratic arc, a contaminated surface, or poor-quality consumables.
How many amps does it take to weld stainless steel?
Stainless steel doesn’t require as much amperage as carbon steel, so you can follow the 2/3 of an amp rule for every one-thousandths of thickness from your material.
What polarity is used for MIG welding stainless steel?
For the majority of welding with stainless steel, you will use DCEP (Direct Current Electrode Positive).
With a cheap MIG welder, you can get a lot accomplished, including work with stainless steel. Just remember to gather the appropriate materials and protect yourself during the job.