Welders use varying weld methods for different kinds of welds. Each welder has a different preference and expertise in various methods. For those new to welding, wire feed welding is the easiest to pick up and thus the best technique. Keep on reading to find out how to wire feed weld.
What is wire feed welding?
Wire feed welding is the same as Metal Inert Gas (MIG) welding and Gas Meta Arc Welding (GMAW). MIG, GMAW, or wire feed welding joins metal by heating the workpiece and a continuously fed filler metal electrode with an electric arc. The process employs the services of shielding gas to protect the weld metal from external environmental contamination.
Wire feed welding machines are specifically designed for mild welding. They utilize an entirely consumable electrode and are ideal for joining nonferrous metals that are relatively softer.
MIG welding may be the easiest to use out of all, but it involves complex technicalities to ensure that the process proves productive. You need to master the use of a welding gun and figure out the correct welding power supply and wire feed unit and speed. You also need to determine and use the ideal shielding gas and wire electrode.
How Wire Feed Welding Works?
Wire feed welding uses a continuously fed wire electrode to produce weld joints. You insert the wire electrode into a machine featuring an electrode holder shaped like a gun. Once you press the trigger, multiple things start to happen at the same time.
- The power supply springs into action and the rollers begin
- The arc springs to life
- The shield gas begins to flow
- The rollers feed the wire
The continuously burning arc heats the base metal and simultaneously melts the wire electrode. The two metals melt together to form the weld joint. Throughout the entire process, the shield gas protects the metals from environmental contamination.
It increases productivity rates as it eliminates the need to stop the process and replace the burnt-out electrode. However, wire feed welding requires skill and technique that you need to master to ensure you produce the perfect weld.
Essential Rules When Wire Feed Welding
All welding requires a certain level of expertise and an in-depth understanding of the technicalities of the process. Here are a few critical rules that you need to follow when you’re using wire feed welding:
In welding, you either push or pull. The standard practice for which route to use is simple. If the welding job produces slag, you need to drag or pull. Simply put, in stick welding or flux-cored wire welding, you bring the wire towards you. In wire feed welding or MIG welding, you push the wire.
In the push technique, you push the gun away from the weld puddle. Since the arc force is directed away from the weld puddle, the push direction produces lower penetration and a flat, wide bead. It’s also called the forehand technique. It offers a better view of the join and allows you to better direct the wire into the joint.
In the pull or drag/backhand technique, the gun is pointed back at the weld puddle and then dragged away from the deposited metal. It produces deeper penetration and a narrow bead, resulting in higher buildup or metal deposit rates.
In MIG welding, you can use either the push or pull technique.
The work angle varies with each metal and joint. It varies by metal, metal thickness, and joint type. There are four significant weld positions:
Flat Position: In the flat position, the kind of joint plays a vital role in deciding the working angle.
For butt joints, the ideal angle between the gun and the workpiece is 90 degrees. Direct the filler metal straight into the joint. Adjust the travel angle to 5 to 15 degrees and maintain it throughout the procedure. To avoid an undercut and to fill up a wide gap completely, you can go back and forth over the joint.
In a T-joint weld, maintain a 45-degree angle between the wire and the workpiece. For a T-joint, the welder needs to employ his expertise and change the angle as needed, especially when making multiple passes. Changing the angle helps avoid uneven weld bead production and also avoids undercuts.
Lap Joints require a work angle between 60 to 70 degrees. You need to adjust the angle as per the metal thickness — the thicker the metal, the bigger the angle.
Horizontal Position: When welding in a horizontal position, the effects of gravity have to be taken into account. The work angle is adjusted between 0 to 15 degrees as needed. A welder adjusts to avoid the filler metal sagging or rolling over toward the bottom of the weld.
The welder also needs to use a combination of push and pull techniques to ensure an even and smooth weld. The travel angle remains the same despite the changes in direction as well as the working angle.
Vertical Position: For welding in an upright position, a pre weld setup holds significant importance. The work angle will depend on multiple factors. However, the travel angle for vertically positioned welds should be around 5 to 15 degrees from the perpendicular position. With the angle, the welder needs to employ the weaving technique to control the size and shape of the weld bead. It also controls the cooling effects of the weld puddle.
Overhead Position: Overhead welds are trickier to deal with. There is no specific work angle for such welds. How well the welder handles such a job depends upon their expertise. Not everybody starts as a pro, but there’s always room for trial and error. You can practice on practice sheets before you start working on the actual weld.
The travel angle is the angle between the gun and the weld in the plane when placed parallel to the travel direction. Under normal welding conditions, welders maintain a travel angle of 5 to 15 degrees. They produce the least amount of spatter, have increased arc stability, and higher penetration levels. Angles above 20 to 25 degrees lower productivity, as they generate more spatters and less weld penetration.
Selecting a wire type is relatively easy. Two wires are most commonly used in wire feed welding.
The first is a good all-rounder wire for all-purpose welding while the second is ideal for use on dirty or rusty steel. ER70S-6 is suitable for repair or maintenance welds as it works best in situations when the job requires more deoxidizers.
When welding thicker metals at higher temperatures, use a 0.035-inch or a 0.045-inch wire depending upon the use and welder’s output range.
A 0.030-inch wire works as an excellent all-rounder choice. However, we suggest you use a 0.035-inch wire for sheets with medium thicknesses and in home and motorsports applications.
On thinner sheets, a 0.023-inch wire works best. It helps control heat input and reduces the chances of a burn through.
Shield gas selection plays a critical role in producing high-quality welds. Utilizing the wrong gas can not only create a porous weld but can also generate harmful fumes that can be possibly toxic.
A combination of 75% Argon and 25% Carbon Dioxide is the best all-purpose shielding gas for all carbon steels. It generates minimal spatter, avoids chances of a burn through on thinner sheets of metal, and creates the best bead appearance.
You can also use 100% CO2, and while that works remarkably well, it does produce a considerable amount of spatter and also generates rougher beads.
The length of the wire that sticks out of the gun plays a crucial role in maintaining arc stability. Welders usually leave 3/8th of an inch sticking out from the welding machine. Any longer than that and the arc will produce sizzling sounds like that of frying bacon.
Tips and Tricks
Welding is a relatively complicated technique to master. Knowing some specific techniques can help you learn the art.
When welding sheet metals, using a 0.9 mm diameter wire works best. You can also get wires ranging from 0.7 mm to 4 mm, depending on the thickness and weld joint. Since the wire diameter and wire choice directly affects the quality of the weld, you must choose the right wire.
Choosing the perfect wire material is also just as crucial. Most electrodes have deoxidizing layers, which keep the base metal protected from contamination and helps improve weld quality.
Use a high ratio of Argon in your shield gas selection. An Argon and CO2 combination works best and provides the ideal protection while creating the optimum environment. The right choice of shield gas is also significant as it directly affects the productivity levels of the process.
Welders use constant current to set up the perfect wire and voltage combination. A continuous current boosts productivity levels.
Practice the procedure beforehand so that you know how to adjust the temperature setting towards the end of the procedure. Lowering the temperature at the right time is critical to ensuring that the weld metal cools completely and on time to form a perfectly smooth weld.
Use the appropriate safety equipment.
When wire feed welding, make sure you have the appropriate protective equipment on. MIG welding is a delicate process, as, in some cases, it results in harmful fume generation. There are also increased chances of radiation burns and electric shock. To protect yourself, you will need:
- Flame resistant overalls
- Safety boots
- Leather gauntlets
- Air fed welding helmet
You need to be protected from possible fire hazards through flame-resistant overalls. The electric arc in wire feed welding is not always stable. Initially, when you’re trying and testing the voltage and amperage setting, the arc may sway and put the welder in harm’s way. In such a situation, if the welders’ clothing is not flame resistant, they may catch fire.
MIG welding also generates a lot of heat, which can lead to severe burns. Flame resistant clothing comes in handy for protection against the heat generated during the process. For additional security, the welder must also wear leather gauntlets.
Leather gauntlets offer better protection as compared to gloves. They cover the welder up to the elbow, which is ideal for such a hazardous welding procedure. All welding jobs generate a lot of heat and can potentially cause severe burns to the welder. We suggest you always use leather gauntlets instead of gloves.
Safety boots are another essential piece of protective equipment. When welding in vertical or overhead positions, a little drop or two of the weld metal may fall to the ground due to gravity. In such situations, the possibility of the molten metal falling onto the welder’s feet poses a severe safety hazard. To protect themselves, the welders need to wear approved safety boots.
Lastly, but most importantly, you need to wear the appropriate welding helmet. The welding helmet performs two essential functions.
- Protects the eyes
- Provides a safe breathing system
All forms of Arc welding produce incredibly bright light. The proximity of the arc and the welder makes it a real safety hazard. Looking at the arc with the naked eye can cause irreparable damage to your retina. An auto-darkening helmet not only protects the eyes but also makes the process easier for the welder.
Besides featuring an auto-darkening lens, the helmet must also have an air-fed ventilation system to eliminate the chances of the welder breathing in toxic fumes. The welder must also be aware of their breathing zone and maintain a reasonable distance from the workpiece.
When using a fume extractor, make sure you place the nozzle in the correct direction so as not to have the fumes blown into your face. Instead, direct the extractor as far away from your breathing zone as possible.
Before you start a welding procedure:
- Make sure you are aware of all hazards involved in the process
- Always check your helmet and other Personal Protective Equipment to ensure it is in line with the requirements of the welding procedure
- Understand the equipment and make sure you know how it works
- Install a Local Exhaust Ventilation and Respiratory Personal Equipment before you begin welding
- Make sure to pass on the information to your co-workers
What is the difference between MIG welder and Wire Feed Welder?
A MIG welder is primarily the same thing as wire feed welding. In MIG welding, you insert the filler metal wire into the gun. The metal wire rolls forward through rollers installed in the machinery and heats up to melt and form the weld.
What is the difference between a TIG welder and a MIG welder?
A MIG and TIG weld both use an arc. The only difference between the two is in the way the arc is used. A MIG welder uses a feed wire that moves through the gun and creates a spark. It heats up and melts to form the weld joint.
TIG welding uses long metal rods instead of metal wires.
What is MIG welding?
MIG stands for Metal Inert Gas welding. It utilizes an electric arc combined with a solid wire electrode. The arc heats the wire, which melts to fill in weld joints. The arc also heats the base metal to ensure both the filler metal and the workpiece merge in a durable bond. The complete name for GMAW is Gas Metal Arc Welding, and it is also known as wire feed welding.
The process also utilizes a shielding gas to ensure that the metal does not react with the gases in the atmosphere, especially Oxygen and Nitrogen.
What is MIG or wire feed welding used for?
Hobbyists, farmers, ranchers, and amateur welders use MIG welding as it is relatively more comfortable to use. Some people even say it is similar to using a glue gun. While that is not entirely true, the process is comparatively easier than other forms of welding.
Wire feed welding is suitable for almost all repair welds on material from 24-gauge to 0.5 inches. However, it does not combat rust, oil, and dirt very well, so make sure to clean and prepare your work surface beforehand to ensure the best quality weld.
How to feed wire in a portable MIG machine?
Portable MIG machinery makes welding jobs a lot more straightforward. The compact mechanism travels to the worksite, significantly reducing travel costs and time. However, using a portable machine can be tricky. Here is a short video on how to feed wire in a portable wire feed welding machine.