Aluminum in its pure form is a relatively soft metal that has many uses, but which requires the addition of an alloy or alloys to increase its strength and to add other qualities suitable for different applications. Common alloys are: copper, magnesium, silicon, manganese and zinc. They are identified by their series numbers:
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Aluminum, especially thin-gauge aluminum, presents some unique welding challenges. For many, GTAW is the preferred process, but GMAW offers some obvious benefits: higher deposition rates, less operator training and higher productivity. With these benefits come a few challenges, namely wire feeding and selecting the right type of filler metal and equipment. These challenges can be easily met, however, by knowing the answers to some common questions.
While filler metal for steel is typically chosen by matching the tensile strengths, strength is only one of the considerations when choosing an aluminum filler metal. Typically, there are several different aluminum filler metals that would be acceptable to use when welding aluminum base materials. In choosing a filler metal, consider:
-Base metal composition
-Ease of welding
-Joint design
-Dilution (when the filler wire and base metal combine in the weld puddle to create a different chemical make up in the weld)
-Strength of the weld
-Hot cracking sensitivity
-Ductility
-Corrosion in service
-Color matching, if the material is anodized
-Elevated service temperature (150-350 Fahrenheit)
Different filler metals address these considerations to varying degrees. In general, if strength is the primary consideration, the filler metal should closely match the base metal in tensile, yield and ductility.
Most consumable manufacturers, as well as the American Welding Society (AWS), offer information listing the relative values of these considerations of their filler metals for each base alloy. Always make sure to use an aluminum filler metal selection chart to address the weld properties listed above.
Traditionally, welders have relied on AWS and wires, as they can be used with the most widely used aluminum alloy base metals. Hobart, however, offers an alternative to filler metals to increase strength and quality. The MaxalMig® aluminum wire offers approximately 20% higher tensile strength and doesn't rely on diluting the aluminum base material to gain strength. This feature often allows welders to make smaller, single-pass welds and still get reliable strength. It also helps minimize the risk of distortion since heat input is lower.
Aluminum as a filler metal has the same oxidation problems as all aluminum. When left open, either on the shelf or installed on the welder, aluminum filler wire will oxidize, which can lead to an erratic arc. The oxidation adds resistance, can produce smut and can change the wire's ability to feed smoothly. Many operators have spent a great deal of time adjusting tension settings, changing contact tips or checking the shielding gas trying to fix the problem when it was the oxidized wire that was at fault.
Because of its low columnar strength, feeding aluminum wire has been likened to pushing a wet noodle through a straw. Birdnesting, or the tangling of the wire between the drive roll and the liner, is a common, time-consuming and costly problem. Clearing it requires the operator to stop welding, cut the wire, discard the wire in the gun and re-feed new wire through the liner. It also may require cleaning or changing the contact tip because of the burnback caused when the wire stops feeding.
There are several ways to feed aluminum wire: Push only, spool gun, push-pull system and continuous feed push-only system.
Push only: Feeding aluminum wire through a push-only system can be difficult, but it can be done on a limited basis. It requires u-groove drive rolls to provide more surface contact with the wire, adequate drive-roll pressure and the ability to keep the gun cable straight. Any resistance in the line will likely cause the wire to misfeed. Thicker wire, such as 1/16 inch, may be fed consistently in a push-feed system. But for thinner gauges, such as .030 inch, push feeding is not very dependable.
Spool gun: Welding aluminum with a spool gun, such as the Spoolmate' or Spoolmatic® series of guns, eliminates the possibility of birdnesting by putting a 4-inch (1-pound) spool on the gun, so the wire only feeds a few inches. Spool guns can accommodate aluminum wire diameters from .023 to 1/16 inch and allow the operator to use longer cables (15-50 foot).
A spool gun needs to have the roll changed after every pound of wire is used, compared with the 16- or 22-pound spool on a push-pull system. In tight spaces, the spool may limit access, requiring the operator to use a longer stickout. If the operator is using several pounds of aluminum per day, the few minutes needed to change spools can add up. Also, the chance of burnback exists when the end of a spool is reached, so many operators stop when a few turns are left on the spool.
Push-pull gun: With a push-pull gun, a motor in the gun pulls the wire through the liner, while the motor in the welder or feeder control becomes an assist motor. By maintaining consistent tension on the wire, the push-pull system helps eliminate birdnesting. It is more ergonomic than the spool gun since the weight of the spool is not in the operator's hands.
Also, the spool needs to be changed less often than on a spool gun and allows the purchase of larger spools. A push-pull gun also allows cables up to 50 feet long. The only disadvantage to push-pull systems is their relatively higher price tag, but the increased productivity and the financial advantage of buying larger spools usually provide a quick return on investment. When you compare the cost of 16 1-pound spools of .035-inch aluminum filler wire with one 16-pound spool of the same diameter wire, plus the time to change 16 spools versus one spool, you'll see that for high-volume use, a push-pull system makes financial sense.
A welding distributor, picked at random, lists a price for a 1-pound spool of .035-inch aluminum wire as $11.46. A 16-pound roll lists for $170.24, which works out to a difference of $0.82 per pound. Now, add the time for 16 spool changes (and possibly burnbacks) for the spool gun as compared with one change for the larger spool. At five minutes to change a spool, that's 80 minutes of extra time for each 16 pounds of filler wire used.
Continuous-feed push system: This is a relatively new addition to the field. This type of system uses a special drive system that maintains continuous contact with the wire and eliminates the possibility of birdnesting since there is no gap between the drive rolls and the liner. While it is limited to pushing the wire 15 feet, the gun is lighter than either the spool gun or the push-pull gun and requires no additional maintenance.
Check out this article for more MIG welding aluminum best practices.
Aluminum is a lightweight metal renowned for its versatility, durability, and corrosion resistance, which makes it widely used in various industries. However, many welders find welding aluminum a challenging task.
To successfully MIG weld aluminum, you will need to follow a couple of steps, and one of the most crucial ones is choosing the best aluminum wire. The choice of welding wire plays a pivotal role in achieving flawless welds, and in this article, we'll explain types of aluminum wire and their effect on the finished weld.
Mig Welding Aluminium Photo by @christurbo (YouTube)Welding wire is a filler metal that is commonly used in wire welding processes (MIG Welding and Flux Core welding). As the name states, wire is a slim metallic rod that creates the arc and fills the gap between two metals. Wire usually comes in coils or spools, and it is fed by a wire feeding system through a liner and MIG gun to the contact tip.
Wire Feeding System Source: https://www.youtube.com/watch?v=twUAa5LWUvkWelding wires can be divided into two groups: solid wires and flux core wires. Solid wires are used in MIG welding, and they require an external shielding gas, while flux-cored wires contain flux that shields the weld. These are some of the most straightforward explanations you'll need to understand if you are new to the world of welding, but if you wish to learn more, make sure you check out our MIG Welding Wire Types article.
If we look at the types of wires, they are usually separated into the group of metals that they are designed to weld. Therefore, you can find steel, stainless steel, and aluminum wires. Our topic today will closely turn to aluminum wires, their types, differences, and requirements for welding.
MIG welding aluminum is one of the most straightforward methods for beginners and hobbyists since it requires less skill compared to TIG welding aluminum, which is often a go-to choice for professionals. When MIG welding aluminum, you will need a proper aluminum filler metal.
Now, this is easier said than done since aluminum alloys come in various grades, which then have different properties which you'll need to match with your wire. Matching the properties of two welded pieces and your wire is crucial in achieving a sound weld.
Photo by @woodweldfabrication (Ins)
However, on the good side, as a hobbyist or occasional welder, you are less likely to deal with specific or rare industrial aluminum grades, so choosing the correct wire for aluminum welding is not a daunting task. For your MIG welding process on aluminum, you are likely to use ER or ER aluminum welding wires.
ER is a general-purpose, all-position aluminum welding wire. It is one of the oldest and most widely used welding and brazing alloys. You can use it to weld , , , , , , , and aluminum alloys, which can be found in many common welding applications, such as bicycles, trucks, trailers, and automotive parts and equipment.
ER/1LB-0.8 1LB Spool .030" Silicon Aluminum MIG Welding Wire
This aluminum alloy usually contains 5% of silicon additives (AWS A5.10 specification allows 4.5-6%), which results in improved fluidity (wetting action) of the weld pool. High fluidity will allow you to achieve spray transfer and produce a weld less sensitive to cracking and a better appealing bead profile and bright weld.
As a hobbyist, you are likely to use .030 and 0.035 aluminum wires in 1-2 lb spools. But keep in mind that they come in industrial grade sizes such as up to 1/16" and spools larger than 10 lbs. However, you are less likely to use thicker wire than 0.035, as aluminum usually comes in thinner gauges.
Mig welding aluminum quad bike rack. Photo by @dghengineering (TikTok'Typical mechanical properties of ER:
ER is another general-purpose aluminum wire that shows great versatility. As , there are many common structural aluminum base alloys that can be welded with . However, compared to ER, ER wire usually contains 5% of magnesium additives (AWS A5.10 specification allows 4.5-5.5%).
ER/1LB-0.8 1LB Spool .030" Magnesium Aluminum MIG Welding Wire
The addition of magnesium to aluminum helps improve the weldability of the metal. This wire has a low melting point and strong weld penetration. This makes it ideal for welding thick materials or materials that are difficult to weld. Additionally, magnesium brings high shear strength and offers excellent corrosion resistance when exposed to saltwater.
ER has a typical tensile strength is 29,000-45,000 psi (200 to 310 MPa), and a Yield strength is 12-30 Ksi (83 to 207 MPa). One of the advantages of filler wire is a much closer color match after anodizing.
Weld aluminum by using ER. Certification: AWS A5.10/ A5.10M: Alloy: ER AWS/ASME SFA A5.10 Photo by @bluedemon (Ins)Typical mechanical properties of ER wire:
To help you make the right choice, here is a head-to-head comparison of crucial aspects of ER and ER wires.
Like its parent metal, aluminum wire has unique properties that make it harder to use and feed. Most importantly, the aluminum filler metal is soft, which makes it highly challenging to feed without interruptions, clogging, or bird nests. Therefore, you will need special welding equipment to achieve smooth wire feed, which is crucial for quality welds. Additionally, the wire must remain clean. Contaminated wire can affect the quality of the weld, even if you cleaned the aluminum oxide with stainless steel brush prior to welding.
A spool gun is a unique piece of welding equipment that recently become mandatory when mig welding aluminum. A spool gun is a pistol grip-style gun with a compartment for a wire spool roll to be attached directly to the gun. This gun has an independent wire feeding system with drive rolls designed to feed the sensitive wires.
LBT150 150AMP Aluminum Welding Spool Gun
So why is the spool gun such a good accessory for aluminum filler metal? The main reason is the significantly shorter way that wire travels from the spool, through the gun, and into the weld. By shortening the course and applying higher wire feed speed, there are minimal chances that soft aluminum wire can tangle on its way to the weld.
As a result, spool guns became necessary for MIG welding aluminum today. However, there are a few drawbacks. The spool gun is limited to a 1 lb aluminum wire spool, and it can be heavy on the hand. As an alternative to weight and spool limitation, some use push-pull gun with added feeding system inside. However, like spool gun, these push-pull systems are considered an accessory you'll have to buy separately.
Spool Gun MIG Welding Aluminum. (0:01-0:58) Photo by @BrandonLund (YouTube)Graphene liner is a cheaper alternative to a spool gun, which solves some of the issues with wire feeding. The liner is a tube or helically wound wire inside the torch that guides the filler wire through torch leads and into the weld. Typically, your MIG torch is equipped with a steel liner which is more than fine when MIG welding steel and solid wires. However, as the soft aluminum filler metal passes through it, it can get damaged or tangled, or an aluminum oxide layer on the wire can strip, resulting in contamination or poor wire feed.
SMX-1.0/1.2 Graphene Aluminum MIG WeldingWire Feed Liner
By replacing steel with a graphene liner, you eliminate most of the issues with aluminum wire feed. Even though the path between the spool and weld remains longer, the risks of wire tangling during the feed are minimal. Still, many don't find it as effective as a spool gun, but if you are on a tight budget, you can always consider it.
How to Change a MIG Gun Liner - YesWelder MIG 250 Pro
Besides skill, MIG welding is an often preferred method for aluminum welding over TIG welding aluminum due to lower costs. The aluminum welding machine isn't the most complex piece of equipment, as you don't need fancy features or AC capability like with TIG. Equipment-wise, the main thing you should worry about when doing aluminum MIG is the wire feed.
Therefore, you will need a MIG welder that is spool gun compatible such as YesWelder MIG-205DS-BS, or a welder that supports high wire feed speed (450-750 imp for thinner wires and spray transfer mode). Most commonly, these are advertised as "MIG welder for aluminum" or "Spool gun compatible", so you cannot do too much wrong.
YesWelder MIG-205DS-B Multi-Process MIG Aluminum Welder
Unlike TIG, you can MIG weld aluminum alloys with DC polarity. Aluminum wires require DCEP polarity but also an argon shielding gas.
Source: https://yeswelder.com/blogs/yeswelder/how-to-setup-and-use-your-mig-welder-for-the-first-time
Here are typical MIG welding parameters that work with both ER and ER wires:
Diameter
If you are looking for more details, kindly visit Aluminum Mig Welding Wire.
WFS
(ipm)
Amperage
Volts
Consumption
(lb/100 ft)
Argon
(cfh)
.030'
480-625
60-175
15-24
0.65-1.25
25-30
.035'
450-750
70-185
15-27
1.0-4.25
30-35
3/64'
330-500
125-260
20-29
1.0-4.25
35-45
1/16'
250-450
170-300
24-30
3.8-6.6
45-775
Theoretically, you can use flux cored arc welding method to join aluminum, but the technological solutions are still not commercialized or even used outside the laboratory. The main issue with flux core welding is the composition of flux that should protect the weld. The typical fluxes developed for stainless steel or mild steel are not chemically more active than aluminum, so the scientists had to start working on new ones.
The new types of fluxes were developed and presented in the labs that work on pure aluminum or aluminum alloys, but due to drawbacks, they never reached commercial use. These fluxes are very corrosive, so every bit of them must be removed from each weld pass before proceeding. Additionally, aluminum fluxes absorb water from the air, which makes storing extremely challenging. Finally, the chemicals in the fluxes are highly environmentally unacceptable.
Other possible issues with flux core aluminum welding emerge with the wire feeding and unpredictable weld results. The aluminum wires are fundamentally softer than solid wires, which makes them hard to feed. Making the wire hollow to fit the flux would make the feeding highly challenging and require special drive rolls and feeding mechanisms. Additionally, combining the fluidity of aluminum and the higher spatter of FCAW can result in very messy welds.
U-type drive roll for aluminum welding wire. Source: https://bancrofteng.com/how-to-solve-wire-feed-problems-when-welding-aluminum/So even if it is theoretically possible, flux core arc welding is not a preferred method for aluminum.
If you browsed the wire market, you might have come across the products advertised as "Flux core aluminum welding wire". If we take a look at the American Welding Society Filler Wire Specification By Material and Welding Process, we can see there is no match for Flux-cored arc welding and aluminum.
Therefore, it is clear that there is yet no flux core welding wire for aluminum that would have its composition and properties specified by AWS or any reputable organization. Even if you find and buy this kind of wire, there is no guarantee you will successfully flux core weld aluminum without tangling, wire burning, spattering, or burning through. That's why we recommend sticking to traditional aluminum welding wires and methods such as MIG or TIG.
Welding wires are an essential part of any weld, and when welding aluminum, you will need to choose a filler wire with similar composition and properties to the base metal. Even though there are various grades of aluminum, as a hobbyist, you are likely to use ER or ER wires. These are both general-type, all-position welding wires that provide good results and desirable weld properties on a wide variety of aluminum alloys, and the choice will differ on specific applications.
The main issue with aluminum welding wires is feedability. Aluminum wires are soft, so they require specialized equipment such as a spool gun, push-pull system, or specific liners. These are considered accessories, which means they are an added cost, but the overall investment is significantly lower compared to TIG.
Welding aluminum with a spool gun by using YesWelder MIG-205DS-B.1.What is ER MIG aluminum welding wire?
ER is a general-purpose, all-position aluminum welding wire. It is one of the oldest and most widely used welding and brazing alloys. You can use it to weld , , , , , , , and aluminum alloys, which can be found in many common welding applications, such as bicycles, trucks, trailers, and automotive parts and equipment.
2.What is ER MIG aluminum welding wire?
ER is another general-purpose aluminum wire that shows great versatility. As , there are many common structural aluminum base alloys that can be welded with . However, compared to ER, ER wire usually contains 5% of magnesium additives (AWS A5.10 specification allows 4.5-5.5%).
3.ER vs. ER Which One To Choose?
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