Custom Sheet Metal Welding
There are three different processes of welding sheet metal, including:
- MIG Weld (Metal Inert Gas): This process uses solid wire electrodes. MIG weld process is suitable for cosmetic projects and weld appearance is crucial.
- TIG Weld (Tungsten Inert Gas): This process uses non-consumable tungsten electrodes.
- Laser Welding: It is a kind of fusion welding process utilizing a laser beam to provide a heat source.
All types of welding processes can be applied to numerous sheet metal materials. It is also a perfect process for sheet metal components to produce finished and semi-finished products. With these capabilities, KDM is capable to provide welding of copper, stainless steel, aluminum, and iron.
KDM has extensive know-how and cutting-edge machinery to provide our clients with the highest precision and clean welding services! Please don’t hesitate to contact us.
Sheet Metal Welding: The Ultimate Guide
I know you are looking for the best techniques for your sheet metal welding processes.
A reason this guide explores everything you need to know about sheet metal welding.
You will not only learn about the techniques, but also joint types and components.
Take a look:
Sheet metal materials are usually very thin and working with them may need extra care because it is a bit complicated.
Too much heat may cause burnout and less heat may lead to little or no penetration at all leading to the creation of brittle joints which are prone to breakage.
There are a lot of factors to consider when working with sheet metals during welding to form joints.
These factors depend on the welder and how experienced they are when it comes to sheet metal welding.
sheet metal welding
However, there are a few things to keep in mind or tips to consider when doing sheet metal welding;
- Minimize burnouts- this happens due to the input of high temperatures which can generally be impossible to work with creating a big hole.
Therefore, it is very important to know what temperatures are appropriate.
- The weld bead appearance- there is the risk of spatter occurring in very high amounts which is normally caused by the appearance of the bead especially when working with stainless steel.
- Placing the torch at the right angle- the amount of energy conveyed depends almost wholly on where the torch has been placed.
This calls for consideration of the melting point and other properties of the metal being welded which will help lessen the risk of getting burnout.
- The gas used for shielding- this choice will determine the productivity rate of the procedure.
It can create weak joints if the energy conveyed is not sufficient, but with high energy, there is risk of creating spatters of a certain amount and this can lead to the material being blown.
There are so many factors to consider when choosing a material for the sheet metal welding parts and these factors include; corrosion resistance, strength, hardness and many more.
For sheet metal welding, the materials discussed below can be used.
- Steel – this class of metals works best with a number of welding methods such as TIG, MIG, resistance and SWAW.
Generally, low carbon steel metals are the easiest metals to weld since it is not as hard as stainless steel.
Stainless steel has very complex chemical properties making it limited to specific methods of welding involving oxidation.
- Aluminum- there are two aluminum grades that can undergo specific welding techniques; 1XXX AND 6XXX.
1XXX series is simple to handle and can be welded easily while 6XXX series requires an appropriate welding technique or procedure and a filler material.
The techniques used here may include; SWAW, TIG AND MIG.
- Titanium- the welding technique for titanium is DC-TIG and can be welded by avoiding oxidation to produce stable and durable joints.
- Cast iron- the technique used here is SWAW.
Cast iron is a bit hard compared to metals like steel and aluminum hence also difficult to weld.
However, it can be preheated to ensure that stronger joints are created during welding.
- Brass and copper- they can be welded through DC-TIG technique.
They have properties making them resistant to corrosion and can be used for various applications.
The welding process must put into consideration the alloys present that can lead to oxidation or cracks.
- Magnesium alloys- responds to AC-TIG welding technique.
For the welding to take place with this alloy, it is important to remove oxides before the process begins.
MIG Sheet Metal Welding
This is also referred to as Gas Metal Arc Welding.
This process involves the use of an uninterrupted stable wire electrode through a gun whose contact tip is charged electrically.
This is to create heat that will melt the metal used to join the two metal sheets.
This welding process is prone to spatter and may be suitable for applications that care less about weld appearances.
MIG sheet metal welding
The speed for this technique is approximately 30” per minute and this is also determined by the size of the weld.
Materials used with this technique may include;
–Carbon Steels-Can be used with this technique due to speed and the fact that carbon steel parts do not fit together closely.
–Stainless steel- Can be used with pulse MIG because there is zero contact between the pool and electrode hence less spatter.
The electric current alternates from high to low levels and at every pulse a molten metal drops to the pool from electrode.
–Aluminum- This material is usually cleaned before the process to do away with surface scale hence less spatter.
This applies the use of a pulse MIG machine and a special gas to create welds with a clean appearance.
TIG Sheet Metal Welding
This is also called gas tungsten arc welding (GTAW) and it differs from MIG because it uses a special kind of tungsten electrode that is non-consumable.
This process obtains heat from the arc made through electricity with the electrode.
The filler material is meant for build-up and a supplement for the weld.
The speed for this technique is at about 7” – 15” per minute and this depends on the size of the fillet, the use of the filler wire.
TIG sheet metal welding
This process can be used perfectly with three types of materials;
–Carbon steels– maybe used only when the size of gun in MIG does not allow access to weld because this process is normally not used with carbon steel due to low speed.
–Stainless steels– basically used with stainless steel due to the fact that stainless steel has a clean appearance needed for cosmetic applications.
During the stainless-steel welding through TIG, the input of heat and required speed must be controlled.
Since stainless steel is receptive to warpage caused by irregular heating patterns.
Warpage in this case means the zones that are affected by heat and there are generally no secondary finishes that can clean up the warp.
May be if the weld can be brushed in order to match the material used for joining them.
–Aluminum– initially, it was only TIG technique which was preferred for the welding that involves aluminum.
However, recently, pulse MIG is making progress in the production of clean surface welding of aluminum sheet metal like required in applications such as cosmetics.
If the material to be used is a bit thick, then there is need for a preheat process to make sure that the weld will be penetrated completely.
There is need for a filler metal which also makes the speed here a bit slow compared to MIG technique process.
Laser welding process consists of the use of a laser beam which provides the heat that is required to melt the metal sheets together.
It needs parts that fit very closely and gap should be at most 005” as the current fabrication processes can create parts that can be welded in this manner.
laser welding sheet metal
It does not need gas shielding for many welds, but this will depend on the design of the weld and the appearance intended.
Some of the advantages of laser welding include; high speed, can weld thin and small sheets and it creates less thermal distortion, there is no need for filler material.
Laser welding is divided into two types; cosmetic weld which creates very smooth surfaces and wide welds and keyhole weld.
It creates burns into the second material via the first material.
The solid weld is created when the molten metal cools.
The machine types used in laser welding are referred to as short wavelength and long wavelength tools and this depend on the wavelength of light in operation.
Short wavelength laser beams have light energy and can be readily absorbed by the material and this leads to quick melting and this makes the process fast.
The materials that can be welded through laser welding include;
–Carbon steels– these can be welded through both keyhole and cosmetic laser welding and can sustain both long and short wavelength machines.
The welded part is very clean and can be moved straight to the painting stage.
–Stainless steels– can be welded through both the short or long wavelength machines.
The application of the welded part will determine if it will go through a cleanup process or not.
An advantage with laser welding of stainless steel is that the speed of the laser helps in eliminating or substantially reducing the heat affected zone.
-Aluminum– this must be used with short wavelength laser beam to avoid any reflections of the laser light.
It can be welded through both keyhole and cosmetic methods.
–Coated steels– are challenging to weld through laser welding, however there are cases when uncoated corners need welding, this can be done through cosmetic laser beam welding.
A lot of spatters are produced due to the melting of the coating material, both long and short wavelength machines can be used to weld these steels.
Resistance Welding – resistance welding and stick welding
This technique is mostly involved in welding iron and steel and it normally results into welds that are of high quality.
It is very cost-effective and very efficient; an electrical resistance is used to heat the material to be welded.
There are four different types of resistance welding;
Spot welding- involves placing the materials to be welded on top each other but the surface to be welded along the same line.
Projection- these are islands that have a lower thermal mass to strike the needed balance in complex applications.
Head welding- the two materials to be joined together and held in clamps, one movable, the other stationary and they are pressed at the same time and combined together.
Roller welding- involves the use of two rollers to press the two materials together.
Welding Thin Gauge Sheet Metal
Welding thin metal sheets can be challenging because it is complicated; too much heat may cause burnout.
While less heat can cause poor weld penetration and end up creating brittle joints.
It is therefore important to choose right welding technique to use, the recommended technique is arc welding to connect the thin gauge metals, however, the techniques that can be used are discussed below:
welding thin gauge sheet metal
Using MIG In Welding Thin Metals.
- Adjusting the weld style: it requires the use of short circuit transfer model which is capable of producing perfect weld even with very thin metals.
This model also reduces the contortion of visible welds on the joints and also minimizes the appearance of any burnouts.
The process requires low heat.
- Shielding gas: this process must involve the use of a protective gas to guarantee the appearance of the bead.
The recommended gas is a mixture of 25% Co2 and 75% argon gas.
- Selection of Filler Metals- choose fillers that are slim; the size of about 0.023 inches in diameter.
- The angle of the torch- place the torch at the right angle to avoid burnout during the SCT model process.
This is because a long distance between the materials and contact tips may create an arc that is not stable.
- Use the appropriate power setting and the right foot pedal. Use the foot pedal to regulate the amount of heat generated by the welding machine this will eliminate burnouts.
- Choosing the correct filler metal- the recommended is between 0.020 to 0.040 inches of thoriated tungsten anodes.
There are acuminated anodes that are used by TIG welders and this give a lot of control of the arc.
The process of welding thin metals through TIG technique involves welding downhill but if there is need to weld uphill then use a lower amperage.
This involves heating a small segment of a plate then allow the weld pool to completely cool.
The process needs a lot of care since the rate of penetration is high and if you are using brittle materials they might break.
The filler material must be of a short diameter which will control the amount of heat that reaches the material.
This process regulates the energy output and that’s why it is popular among welders and it also allows for repair of mistakes that may have occurred during welding.
This refers to how a two or more pieces of metal sheets are joined or aligned together through welding.
The choice of a joint depends on the design and requirements of the welded part and this needs keen attention and skills.
Some of the joints are discussed below;
Butt Joint Welding
Two pieces of metal are put together on the same plane and they are joined on the sides through welding.
This type is the most commonly used and it is very simple; there are also several variations of butt welds.
butt joint welding
Each of them serves a purpose and some of these examples include; double v, square, single j, double u grooves, double j, single bevel and many more.
Tee Joint Welding
The two materials to be welded intersect at the angle of 900 forming a t-shape.
These joints can also be called the fillet welds and are mostly achieved when a tube is welded with a base plate.
Tee joint weld
The welding styles that produce tee joints include; melt through weld, j-groove weld, slot weld, plug weld and many more.
Corner Joint welding
This is almost the same as tee joint welding but here the material is placed at the corner of the base material.
This forms an L-shaped joint and these are some of the most commonly used joints in the metal manufacture industries.
It forms v-groove and square butt joints and the styles used here are j-groove, v-groove, fillet, spot , edge, corner-flange, bevel-groove and many more.
Lap Joint Welding
These are the improved version of a butt joint formed by placing two pieces of metal sheets in overlapping positions one on top of the other.
They are mainly done when there are thinner materials involved and they are prone to corrosion due to the overlap.
Edge Joint Welding
In this joint, two metal sheets are placed together on their surfaces with no overlap to create even edges.
Both or one of the metal sheets is bent at an angle to form the required shape.
The are styles that can be used with edge joint welding; U-groove, V-groove, J-groove, Corner-flange, Bevel-groove, Square-groove, Edge-flange.
This type of joint is prone to corrosion, and it is more porous, and other defects such as slag inclusion may also occur.
Grooved Seam Joint Welding
It combines both open hems and flash lap.
The edges of the two metal sheets are joined to form open hem like two people locking their fingers together.
It is sometimes referred to as lock seams, it is very easy and simple to create.
Double corner seam joint welding
Grooved seam joint
It is a combination of corner joint and grooved joint and the form a corner at an angle of 900.
It is suitable for forming compound curves and needs special machines to create it.
For all your sheet metal welding processes, contact us now.