Sheet Metal Welding: Process, Types and Tips
Sheet metal welding is a crucial process in various industries where joining thin metal sheets is necessary to fabricate structures, components, and assemblies. This welding method plays a vital role in industries such as automotive, aerospace, construction, and manufacturing.
So, You never want to go wrong with sheet metal welding. Read this article, you can have a preliminary understanding of the various methods and applications of sheet metal welding.
What Is Sheet Metal Welding?
Sheet metal welding is the process through which a thin sheet of metal is welded to another sheet or metal component. It is mostly used in the fabrication of structural elements and gadgets, including ventilation ducts and other sheet metal parts.
How to weld sheet metal?
Sheet metal welding is done by heating two thin sheets of metal to melting point. The melted sheets are then skillfully joined together using a torch to form the desired shape and specifications.
The following is sheet metal welding processes
Step 1: Prepare the work area:
Clear the work area of any flammable materials and make sure you have adequate ventilation. Welding produces intense heat and fumes, so it’s important to work in a well-ventilated space or use exhaust fans.
Step 2: Clean the metal surfaces
Remove any dirt, oil, paint, or rust from the sheet metal surfaces you plan to weld. Use a wire brush, grinder, or solvent to clean the metal thoroughly. Proper cleaning ensures a strong and contamination-free weld.
Step 3: Clamp the sheets parts
Use clamps or magnetic welding squares to hold the sheets firmly in place. This helps to prevent warping or distortion weld thin sheet metal during the welding process. Set up your welding equipment: Adjust the welding machine settings according to the thickness of the sheet metal and the type of welding method you’re using. Refer to the manufacturer’s guidelines for specific recommendations.
Step 4: Set up your welding equipment
Adjust the welding machine settings according to the thickness of the sheet metal and the type of welding method you’re using. Refer to the manufacturer’s guidelines for specific recommendations.
Step 5: Start welding
Position the welding torch or gun at a slight angle, typically around 10-15 degrees, and maintain a consistent distance between the nozzle and the workpiece. Begin welding along the joint, moving the torch in a steady motion to create a continuous weld bead.
The speed of movement depends on the thickness of the metal and the types of welding or method you’re using. Take care not to apply excessive heat, as it can warp or burn through the thin sheet metal.
There are many different types of welding process, Today we will discuss the 7 commonly used methods.
7 Commons Sheet Metal Welding Methods
Sheet metal welding is done by heating two thin sheets of metal to melting point. The melted sheets are then skillfully joined together using a torch to form the desired shape and specifications.
1. MIG Welding
In metal inert gas welding (MIG) or metal arc welding, an electric arc is used to melt filler material and join two or more pieces of sheet metal together. An inert shielding gas (pure helium or argon) is used to protect the arc from atmospheric contamination.
Currently, MIG is the most popular welding method because it allows for incredibly fast welding speeds. It is also very cost-effective.
2. TIG Welding
Tungsten inert gas (TIG) welding also called Gas Tungsten Arc Welding, TIG welding uses a tungsten electrode that does not melt due to its high melting point (3,422 °C).
The filler material is heated and liquefied by the arc that this electrode emits. To prevent the oxidation of the molten weld pool and the heated material, an inert shielding gas is used.
TIG welding produces perfect, high quality welds and spatter-free weld seams. However, it is time-consuming and requires more expertise.
3. Stick Welding
Stick welding is the informal name of shielded metal arc welding, also known as manual metal arc welding or flux shielded manual arc welding process. A consumable electrode covered with flux is used to establish the connection when doing stick welding.
The electrode’s flux coating breaks down as the weld is applied, releasing vapors that act as shielding gas. Thus, stick welding does not employ any shielding gas.
4. Gas Metal Arc Welding
In the Arc welding process, an electric arc is used to create intense heat that melts the metals. A bond is created between the molten metals as they cool. In order to protect the molten metal from atmospheric contaminants, a shielding gas, vapor, or slag is used.
5. Plasma Arc Welding
Plasma arc welding is a fusion welding method that utilizes a concentrated and high-energy density plasma arc beam as the heat source for welding.
One significant advantage of plasma arc welding is its ability to minimize stress deformation in the welded materials. The focused plasma arc provides concentrated heat, reducing the likelihood of warping or distortion in the workpiece.
6. Spot Welding
Spot welding or resistance spot welding is a resistance welding process that welds metals by applying pressure while supplying electric current which heats up the weld area.
7. Electron Beam and Laser Welding
Electron Beam Welding (EBW) and Laser beam welding is a process that makes use of a high-density laser beam to join metals or thermoplastics. Both methods offer high precision, deep penetration, and minimal heat-affected zones.
To decide which sheet metal welding method best suits your design, you will have to consider the welding surface.
5 commons sheet metal welding surfaces
Sheet metal welding is done by heating two thin sheets of metal to melting point. The melted sheets are then skillfully joined together using a torch to form the desired shape and specifications.
1. Flat Surface
When welding a flat surface, the welder points the torch from the upper side of the joint. This way the molten flows by gravity.
For the best flat welding results, the tip should be at an angle to the metal surface. The flame should also be carefully directed toward the joining point.
MIG and TIG welding work best overhead welding on flat surface.
2. Horizontal Surface
On horizontal surface welding, the metal sheets appear flat to the welder. Horizontal welding can either be in the form of a fillet weld or a groove weld.
3. Fillet Weld
A piece of metal is put on top of another piece of metal at a right angle. Both metals are heated from the upper end until malleable enough to fuse together. The final weld takes an ‘L’ or ‘T’ shape.
In arc welding, about 80% of the joints made are fillet welds
4. Groove Weld
In groove welding, the metal pieces to be joined are on the same plane. Groove machining is done before welding the beveled surfaces together in a seam.
Laser welding produces great grove welds.
5. Vertical Surface
The weld is applied to a vertical surface or one that is inclined 45 degrees or less. Welding on a vertical surface is more difficult since the molten metal may flow down by gravity. Fast-freeze or fill-freeze electrodes are used to overcome this.
Stick welding is best suited for this kind of surface.
What are the easiest metals to weld?
There are many different sizes and densities of metal, each with its own suitable welding method. We are going to discuss 7 metals that are easy to weld.
Mild Steel
Mild steel contains low levels of carbon (0.25-30%). It is very ductile, formable and weldable. Thus, it is well-suited for a wide range of welding applications.
MIG and TIG methods can be used for welding mild steel.
Stainless Steel
Stainless steel is a type of steel alloy that contains at least 10.5% chromium, which makes it resistant to corrosion. It is highly preferred in harsh-environment applications such as chemical processing, food preparation, and maritime applications.
The best method for welding stainless steel in MIG
Aluminum
Aluminum has a low melting point that ranges from 650 to 700°C which makes it good for welding. It has an excellent strength-to-weight ratio which makes it suitable for manufacturing and construction of thin materials. Aluminum can be welded using most of the welding methods, however, for best results use TIG welding or MIG welding.
Bronze
Bronze is highly malleable and resistant to corrosion. It is also harder than pure iron. For this reason, bronze is excellent for making medals, musical instruments, bearings and bushes for industrial use.
MIG or TIG welding are the processes of choice when welding bronze.
Copper
It is easy to shape, cut, bend, and weld copper with other metals since it is a non-ferrous and soft. Copper is perfect for electrical wiring and copper piping and tubing because of its great corrosion resistance, thermal and electrical conductivity properties.
The MIG welding method is the best for welding copper.
Cast Iron
Cast iron is resistant to wear and is very durable. It has a high carbon content (2-4%) which makes it difficult to weld. A lot of care and skill is needed when heating or cooling to avoid cracking after welding.
MIG method is considered the best technique to weld cast iron.
Galvanised Metal
Galvanized metal usually has a zinc coating that protects it from rusting. Care should be taken when welding galvanized metal to avoid inhaling toxic zinc fumes.
MIG and stick welding methods are commonly used for welding galvanized metal.
All of the metals we have discussed, mild steel is the easiest to weld.
7 Tips for Welding Sheet Metal
1. Carefully Consider The Appropriate Welding Method
There is always the most appropriate method for welding a certain type of sheet metal. This is dictated by the properties of the metal and the nature of the project. Modern technology has made it easier to weld tough metals.
2. Use Clean and Dry Tools
This will protect your metals from rusting and corrosion. It is safe to always have a working fire extinguisher near you in case of a fire.
3. Always Perform A Test Run on The Metal
Before you begin welding any sheet metal, it is very important to do a test run on it. This helps in determining the method you will use and other specific conditions, such as heat requirements during sheet metal welding.
4. Consider the Amount of Heat Needed
Too much heat can cause the sheet metal to melt, resulting in joint failure. Always use a different heating type for different metals in order to have a successful sheet metal weld.
5. Do Skip Welding
The skip welding technique helps you avoid warping and deforming the metal. This involves making a number of stitches at key places in order to hold the sheet metal in place. The skipped areas of filler metal are then welded after a short moment of cooling.
6. Do Tack Welding
Tack welds are small temporary welds that help hold the sheet metals together as they wait for the final welding. The tacks are placed in the middle of the 1 mm gap, which is usually left between the parts being welded. Fixtures to hold the metals together are not needed when this technique is applied. Tack welding will help preserve the appropriate spacing and keep the metal parts well aligned.
7. Use Wires of the Smallest Diameter
If you are just starting out, using the smallest wires available will help you get the hang of welding. You will have better control of the process and can easily correct any errors. It is also important to note that different sheet metals require different wire sizes.
FAQs
Q: What welding is the cleanest?
A: Among various welding processes, TIG (Gas Tungsten Arc Welding) is often considered one of the cleanest welding methods due to its precise control, minimal spatter, low fumes, and the ability to produce high-quality, visually appealing welds.
Q: Is it better to TIG or MIG weld sheet metal?
A: TIG welding is generally preferred for sheet metal welding due to its precise control, ability to weld thin materials, and high-quality welds. MIG welding is chosen when there is a need for high productivity, fast welding speeds, and efficient welds on larger projects involving thick metals.
Q: What size MIG wire is best for sheet metal?
A: When it comes to welding sheet metal with a MIG (Metal Inert Gas) welder, it is generally recommended to use a smaller diameter wire. The most commonly used wire size for welding sheet metal is 0.023 or 0.030 inches (0.6 or 0.8 mm).
The smaller wire diameter helps to provide better control over the heat input and reduces the risk of burning through the thin sheet metal. It also allows for better precision and finer welds.
Author
Gavin Leo is a technical writer at Aria with 8 years of experience in Engineering, He proficient in machining characteristics and surface finish process of various materials. and participated in the development of more than 100complex injection molding and CNC machining projects. He is passionate about sharing his knowledge and experience.