As you know, the way to join stainless steel parts, either for repair work or even for craft projects, is welding. But what type of welding is best for stainless steel?
Before continuing with the article, it is recommended that you take a look at our article Types of welding: TIG vs. MIG vs. Electrode vs. Arc, where we explain the different welding methods and the advantages and disadvantages of each of them.
This article explains the different ways of welding stainless steel and the most appropriate methods to do so.
From these options, each one must choose the most appropriate process according to the application that will be given. Let’s go there!
- 1 Before you start
- 1.1 Identify the type of stainless steel you want to weld.
- 1.2 Choose the right filler metal for your type of steel.
- 1.3 Choose the type of joint you need to weld.
- 1.4 Secure the parts you are going to weld
- 1.5 Clean the base stainless steel
- 1.6 Type of welding for stainless steel
- 1.7 Gas for welding stainless steel with MIG or TIG
- 1.8 One last step before starting welding: Protection
- 2 TIG welding for stainless steel or How to weld stainless steel with TIG
- 3 MIG welding for stainless steel or How to weld stainless steel with MIG
- 4 🔥 MIG Welding Stainless Steel
- 4.1 Forney Easy Weld 140 MP, Multi-Process Welder
- 4.2 PrimeWeld Pilot Arc 50A Plasma Cutter, 200A TIG/Stick Welder Combo, Multipurpose Welding Machine for Home or Jobsite Use with 1/2-inch Clean Cut, Plasma Cutter, TIG Welder and Stick Welder, CT520DP
- 4.3 LOTOS MIG175 175AMP Mig Welder with Free Spool Gun, Mask, Aluminum Welding Wires, Solid Wires, Argon Regulator, Standard MIG Gun
- 4.4 Hobart H522506-R19 0.030-Inch 2-Pound ER308L Stainless Steel Welding Wire
- 4.5 US Forge Welding Stainless Steel MIG Wire .030 2-Pound Spool #00676
- 4.6 Blue Demon 308LFC-O X .035 X 1# Spool stainless steel flux cored gasless welding wire
- 4.7 Forney Easy Weld 140 MP, Multi-Process Welder & Antra Welding Helmet AH6-260-0000 Solar Power Auto Darkening Wide Shade Range 4/5-9/9-13 with Grinding 6+1 Extra lens covers Stable
- 4.8 Forney Easy Weld 140 MP, Multi-Process Welder & 60172 Contact Tip For Mig Welding, Tweco Binzel or Clarke.035, 4-Pack,Copper
- 4.9 VIVOHOME 3 In 1 Multi-functional Plasma Cutter Cutting TIG STICK/MMA Welding Machine Dual Voltage 110/220V CT520DM Blue
- 4.10 Welding Mig Wire SW-316L Flux Core Welder 33 lb Stainless Steel Vacuumed Package (1.2 mm (.045 in))
- 4.11 160A TIG-Torch 140A Stick Arc Welder & 30A Plasma Cutter 3-in-1 Combo Welding
- 4.12 W309 Inverter Welding Equipment,Features of Handheld Arc Welding Machine Series, DC12V/24V professional Welder Equipment for Welding on Various Acidic and Alkaline Stick Electrodes
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Before you start
In this complete guide, we will go step by step. You should know some things before you start welding, and that is necessary to choose the best welding method to meet your needs.
Identify the type of stainless steel you want to weld.
Stainless steel is composed of iron (Fe), Carbon (C), and Chrome (Cr). The fundamental element is iron, but it is chromium that makes steel stainless. For this, the minimum proportion of chromium must be 11.5%.
Stainless steels are divided into three main groups (others are not used as much), and each type is identified by the three digits that are usually printed on the steel:
- Martensitic stainless steel: It is the steel whose chromium ratio is between 11.5% and 18%. It is used for wear-resistant projects. It is magnetic and produces long white sparks with few forks. Some examples are AISI 410, 416, 420, 431, 501, and 502 sheets of steel.
- Ferritic steel: It is the steel that contains between 17-18% and 27% chromium. It is widespread, and its high carbon content makes it magnetic. When it is milled, it produces white or red sparks with few forks. Examples of ferritic steel are AISI 405, 409, 432, 439, 442, and 446.
- Austenitic steel: The total nickel and chromium content is at least 23%. They are essentially non-magnetic in the annealing condition and do not harden by heat treatment. It is a fairly common type of steel, and they usually start with the digit 3.
Choose the right filler metal for your type of steel.
Depending on the type of stainless steel you have to weld, you have to choose a filler metal accordingly. If the metals you must join are different, you have to choose it based on less cracking chance and the most compatible with the base metal.
In the following tables, we help you choose the filling material for your stainless steel:
Contribution metal for martensitic stainless steels
|AISI steel||Recommended input metal||Alternative input metal|
|403||410||308, 347, 309|
|410, 410S||410||308, 347, 309|
|414||410||410 NM, 309|
Contribution metal for ferritic stainless steels
|AISI steel||Recommended input metal||Alternative input metal|
|405||410||308L, 309, 410NM|
Contribution metal for austenitic stainless steels
|AISI steel||Recommended input metal||Alternative input metal|
|201, 202, 205||240||308, 347, 309|
|301, 302, 302B||308||347, 309|
|304, 304L||308L||347, 309|
|316, 309S||309||309CB, 310|
|310, 310S, 314||310||310CB, 310MO|
|316, 316L||316, 316L||309MO, 317|
|317||317||317L, 309MO, 318|
|321||347||309CB, 310CB, 321|
|347, 348, 347H||347||309CB, 310CB|
If you are not sure of the type of stainless steel you have, the 309 works well in most situations.
Choose the type of joint you need to weld.
Depending on how you need to join the pieces together, you will need to make one point. Each joint can be welded in different ways, depending on the thickness and shape of the joint. The most common junctions are the T-joint, the overlap joint, the edge joint, the corner joint, and the top joint.
Secure the parts you are going to weld
Place the pieces you will weld on a work surface where you can work with stainless steel. Put the two pieces as you want to join them using different accessories that usually bring the welding tables.
If you have a normal table, you can secure them with parents or cheaters as firmly as possible so that they do not move while welding.
Clean the base stainless steel
Use a specific wire brush for stainless steel to clean the metal. Rub the brush to remove all impurities, and review with a wet rag of acetone to finish cleaning all debris. This makes welding better.
If necessary, sandpaper and grinders can also be used to clean the steel and remove all impurities.
Type of welding for stainless steel
The most suitable processes for welding stainless steel are MIG and TIG. Although arc welding can also be used to weld stainless steel, it is not the most appropriate method, so we recommend that you opt for TIG or MIG welding.
Gas for welding stainless steel with MIG or TIG
The gas we need for our project depends on the type of welding we are going to use (MIG or TIG), and depending on that, the type of stainless steel we have or the filler material we use.
In the following table, we show you with which gas the stainless steel is welded in each case:
|Filling material/steel type||Basic and rutile tubular thread||Solid thread and metallic filler||–|
|Martensitic||68% Argon, 20% Helium, 12% Dioxide c.||63% Argon, 35% Helium, 2% Dioxide c.||70% Argon, 30% Helium|
|Ferritic||68% Argon, 20% Helium, 12% Dioxide c.||63% Argon, 35% Helium, 2% Dioxide c.||70% Argon, 30% Helium|
|Austensitic||68% Argon, 20% Helium, 12% Dioxide c.||63% Argon, 35% Helium, 2% Dioxide c.||98% Argon, 2% Helium|
Although these are the ideal gases, other mixtures can also be used. A gas with a mixture of 90% Helium, 7.5% Argon, and 2.5% Carbon Dioxide can be used for MIG welding of stainless steel and 98% Argon and 2% Carbon Dioxide TIG stainless steel welding.
One last step before starting welding: Protection
During welding, sparks can always jump, so it is important to use as much protection as possible. The use of gloves and darkening helmets is vital and should be the minimum protection used for any welding work.
Welding apron, respirator mask, and safety shoes are also recommended. But, if you don’t have them, you should at least wear a long-sleeved shirt and long pants to avoid exposing the skin to any dangerous situation.
Read Next – MIG Vs. TIG Welding
TIG welding for stainless steel or How to weld stainless steel with TIG
As we have mentioned before, TIG welding will be used to weld stainless steel of little thickness, approximately up to 6 mm. From then on, TIG welding will not be economical.
In TIG welding ( Tungsten Inert Gas), also known as GTAW (Gas Tungsten Arc Welding), the electric arc is established between the base metal and a non-consumable Tungsten electrode. All this is done in a protective atmosphere created by the inert gas chosen for the project. This gas is used to protect the metal we are melting for air welding.
The trouble is that TIG welding equipment is a little more complicated to use than MIG welders, and the welding process is also slower. On the contrary, it can create stronger and more durable joints than MIG welds when done correctly.
Insert the sharp tungsten rod into the torch, and then start the gas. Then, open the electrode by turning the torch, and put the tungsten rod of the appropriate diameter in the center of the cylinder. Adjust the rod, letting it protrude a little.
Turn on and configure the soldering iron.
Please turn on the soldering iron, setting it to DC (Continuous Current) mode. It will help if you put it in this configuration to weld the stainless steel properly.
In other inverter welders, which can use different functions and types of welding, it is sufficient to put it in TIG mode, or TIG LIFT.
Read Next – What Is MIG welding.
Get ready to start welding.
Light the TIG torch and put it next to the joint you wish to weld. Hold the torch about 2 or 3 centimeters from the pieces’ junction and at an angle of 75 degrees. Hold the torch at this distance and in this position while welding.
TIG welding process in stainless steel
To activate the torch, they usually have a pedal, which lights the torch when pressed. You have to keep the torch still in one place until you see the metal melt, and when this happens, you have to move it to weld the entire joint.
You have to make sure that the metal does not splash, and if it does, you should raise the welder’s amperage. It is a sign that the torch does not have enough strength. On the contrary, if you have too much energy or strength, you will melt too much metal.
Fill the gasket while moving the rod.
Hold the rod with one hand and the torch with the other. Pass the filler rod in the molten metal to fill the joint and create the cord along the entire joint.
Let it cool
Before moving the new part, you just welded, let it dry. The union has to solidify completely before moving it. The torch must also be cooled before storing it since if it is still hot, it can cause a fire.
If you want to see on the video how the welding of stainless steel with TIG is done correctly, we leave you a video so you can do it:
MIG welding for stainless steel or How to weld stainless steel with MIG
MIG welding, also known as gas metal arc welding (GMAW), is used to weld thick pieces. This welding is faster than TIG welding and easier to do, so you don’t have to be an experienced welder to get a good weld. The bad thing is that the union that is created is not so durable. It is more fragile. So for those who ask if you can weld stainless steel with MIG, the answer is YES.
This MIG welding process, and the MAG (Metal Active Gas) process, are used to protect the welding with inert gas since an electric arc is established between a consumable electrode and the stainless steel part are going to weld. The MIG torch has the filling material inside so that it can be welded with one hand. Active gases such as carbon dioxide, oxygen, or hydrogen are usually used to achieve better arc action, but this will depend on the gas mixture you have chosen.
If you weld stainless steel using MIG welding, you have all the information you need about MIG welding machines in this article.
Without lengthening more, let’s do it, here we show you how to weld stainless steel with MIG :
The first thing to do is pass the filler wire through the MIG machine’s reel and take it out through the torch’s tip. This wire has to be a little protruding from the torch, about half a centimeter. Once you have put the wire in the correct position, you only have to activate the gas to weld stainless steel with MIG to start welding.
Hold the torch at 30 ° above the weld joint.
You have to hold the torch at a 30º angle to the pieces that you must join. You have to have the torch in a position that allows you to reach the edge of the two pieces so that the flame heats the pieces. In this way, a weld bead is formed in the joint with the liquid metal created when melted.
To do it correctly, the metal cannot splash, and if it does, it is a sign that you need to use more power. And on the contrary, if the metal melts too quickly, you must lower the power to achieve a smooth liquid cord so that you can easily control it.
Move the torch over the edge to join the entire joint.
You have to move the torch little by little, keeping the angle of 30º along the entire edge of the pieces to fill the joint. Do it at a constant speed so that the welding is uniform throughout the joint. This way, you will create a weld bead throughout the entire joint.
Before moving the torch forward, you have to make sure that the gasket has been filled smoothly and evenly. And if you move very fast, the steel will not melt enough, and the union will be fragile. And otherwise, you will melt too much metal, which is also not convenient.
Let the solder cool
When you have finished passing the torch all over the edge, the welding will be finished. At this tme, do not forget to turn off the gas. Once you finish, you must let both the welding and the torch cool down.
Normally with MIG welding, this usually happens very fast, so you don’t have to wait long.
Finally, I leave you with a video where you can see how the welding of stainless steel is performed:
I hope you found the article useful! You can write us with any questions!
🔥 MIG Welding Stainless Steel
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