sino welding Product Page
From its strength and versatility to its corrosion resistance, aluminum offers benefits that make it an appealing material for a variety of industries. The material, however, is not without its challenges when it comes to welding. Because of its low melting temperature and high thermal conductivity, extra care must be taken to prevent burn through on thinner material and to ensure adequate fusion or penetration on thicker material. Using the appropriate equipment' machines that offer Pulsed MIG capabilities or TIG capabilities ' is important. So too is selecting the right filler metal and understanding the weld characteristics each type provides.
There are many aluminum filler metals available in the marketplace, including those for applications found in aerospace or architectural structures to filler metals for heat exchangers, trailer fabrication and more. The filler metals range from pure aluminum to varieties with added copper, silicon or magnesium.
Among the variety of aluminum filler metals, and alloys are the most common and the least expensive. Together, those filler metals are used for welding about 80 percent of the time and are available in wires for MIG welding or cut-lengths (often called filler rods or straight lengths) for TIG welding. Knowing how to choose between the two alloys, as well as the characteristics each provide is important to producing good weld quality.
Aluminum filler metal characteristics
As with any type of filler metal, and aluminum alloys each have unique characteristics.
filler metals tend to have a more fluid weld pool due to the addition of silicon (5 percent), which allows the bead to 'wet out' or flow into the base metal more easily. This characteristic produces a more aesthetically pleasing weld requiring less clean up, reduces leaks and minimizes cracking.
filler metals contain 5 percent magnesium. As with the silicon in a product, the addition of this alloying element affects the performance of the filler metal. In this case, the magnesium increases the strength and toughness of the weld. When welding with aluminum filler metals, the resulting weld tends to be rippled rather than smooth and due to the 5 percent magnesium, more smut (black soot) could be present at the edges of the weld that the welding operator will need to clean.
Both and filler metals operate with 100 percent argon shielding gas, as it provides good arc initiation and stability. Thicker aluminum applications sometimes require the addition of helium, which improves heat transfer to the base metal and helps increase weld penetration. Helium can be expensive, though, and the application often sacrifices arc stability when it is added.
How to make the selection
The goal when selecting aluminum filler metals is to choose an alloy that produces a weld that best meets the requirements of the product and its intended use. Sometimes the strongest weld is desirable ' other times, leak resistance, ductility, corrosion resistance or toughness are more important.
When trying to choose between the common and aluminum filler metals, there is a series of five questions to ask to narrow down the selection.
1. What is the aluminum base designation?
2. Will the welded component be exposed to sustained elevated temperature?
3. Will the weldment be subjected to post-weld anodizing?
4. Will shear strength, ductility and toughness be prime considerations?
5. Will post-weld heat treatment be performed?
Providing the base metal is compatible, a aluminum filler metal will be best for the following:
' Applications that will be subject to long-term elevated temperature exposure (above 150 degrees Fahrenheit).
' Applications where it is necessary to reduce the risk of termination and shrinkage cracking.
' Applications where aesthetics are particularly important, since these filler metals provide bright, clean welds.
' Applications where distortion is of particular concern, as it minimizes this defect.'
A aluminum filler metal would be most appropriate for:
' Welding on 5XXX or 6XXX series of aluminum when tensile strength is most important.
' Achieving good anodized color matching on 5XXX and 6XXX base metals.
' Applications requiring higher ductility and toughness (such as those subject to dynamic loading).
' Applications requiring higher shear strength.
When welding 6XXX series aluminum or 5XXX series aluminum containing less than 3 percent magnesium, it is possible to use either a or a filler metal to complete the job. The same holds true for higher shear strength applications; however, it typically takes three fillet passes with a product to equal the shear strength of one pass using a filler metal.'
Proper storage and handling'
Proper storage and handling of aluminum filler metals is essential to ensuring the highest quality welds. It is important to keep the filler metals in a clean, dry area that is of a similar ambient temperature as the weld cell. Moving them from a cold area to a warmer area could cause condensation to form on the surface of filler metals and lead to poor weld quality.
If you want to learn more, please visit our website aluminium tig welder exporters.
If a spool of aluminum wire isn't going to be used cover the spool with the plastic bag the wire shipped in or with another protective cover. TIG cut-lengths are best stored in their original box to protect against dirt and debris.
Getting the best results
In any welding application, the goal is to complete the job with high quality and efficient results. Speed and weld integrity are just as important when welding aluminum as any other material. Knowing the basic filler metal characteristics and selection criteria for applications employing this material is a good first step in getting the best welding performance. Additional practice with welding this material ' especially for welding operators new to the material ' is also a good idea. Consider welding scrap materials as a starting point to get a firsthand experience of the different operating characteristics of aluminum filler metals, including the and alloys discussed here. And when additional information about the aluminum welding process is necessary, look for resources with a local welding distributor or filler metal manufacturer to help. They often have technical support specialists to offer advice.
Additional information: equipment considerations
'In addition to proper selection, storage and handling with and filler metals ' or any aluminum filler metals for that matter ' it is important to have the right welding equipment for the job. This equipment includes:
A spool gun or push-pull gun for the MIG welding process. These guns provide consistent feeding of the aluminum filler metals, minimize wire feeding issues and allow for welding further distances from the wire feeder (often as far as 30 feet away).
U-groove drive rolls. These drive rolls prevent the wire from being pinched or compressed, and help ensure proper wire feeding.
Nylon inlet guides and liners. Unlike metal components, nylon components won't 'shave' the wire as it feeds through from the wire feeder to the contact tip, lessening the opportunity for build-up of debris inside the liner.
Contact tips for aluminum wire. Consumables for aluminum wires typically have an 'A' (for aluminum) stamped on them and are sized accordingly for these type of wires. For example, and wires are available in 0.047 inch (3/64 inch) diameters (as opposed to the standard 0.045-inch diameter of steel wires), so the corresponding bore on the contact tip for these wires is slightly oversized, allowing for smooth wire feeding and good arc stability.
Welding Aluminum: Troubleshooting Questions Answered
How to Successfully MIG Weld Aluminum [Guide]
Here are six common challenges welders may encounter in industrial aluminum welding applications and some troubleshooting tips for dealing with them.
Lack of fusion or lack of penetration: Lack of penetration is often seen at the start of the weld, while lack of fusion typically happens at the weld toes. Issues with weld fusion and penetration can stem from the process, filler metals or parameters being used. Trying to weld aluminum using mild steel parameters can result in fusion or penetration issues. Using undersized filler metals can also cause a lack of penetration in the root, as can too little heat. Try increasing the voltage or wire feed speed to resolve fusion issues. Because aluminum conducts heat much faster than steel, it is prone to lack of fusion at the start of a weld until enough energy is put into the weld. Some welding equipment addresses this by automatically ramping up the current at the start of a weld and then decreasing it to avoid too much heat buildup. A failure to clean the oxides from the base material surface can also cause lack of fusion, since the oxide takes a lot of energy to melt.
TIG welding can often avoid the problem with lack of fusion at the beginning of welds since the weld puddle can be established prior to the filler metal being added. In the case of lack of penetration, increasing the amperage or utilizing more electrode negative amperage will put more heat into the weld zone.
Burn-through: On the opposite end of the spectrum, too much heat can also cause problems. Excess heat input may be caused by setting voltage or wire feed speed too high or by too slow of a travel speed. This can lead to burn-through, especially on thinner-gauge aluminum. Generally, aluminum requires a faster travel speed than steel to avoid heat buildup. Overwelding also adds more heat and can result in burn-through. When TIG welding, reduce the welding amperage or add more filler material rod (by increasing the rod diameter or pushing more length in at each addition). This has the same effect as putting an ice cube in a drink; it cools the puddle down.
Poor wire feedability: Wire-feeding issues are common in MIG welding. Because of its low columnar strength, feeding aluminum wire has been likened to pushing a wet noodle through a straw. Bird-nesting, or the tangling of the wire between the drive roll and the liner, is a time-consuming and costly problem. Burnback can also result when the wire stops feeding. Proper equipment setup and gun liner installation can help prevent feeding issues. Also, use the largest wire diameter practical. The pulsed welding process frequently allows one size larger wire diameter to be used at the same amperage settings as a smaller wire diameter, which helps reduce feeding problems without adding excessive heat input.
Inconsistent bead profile: While you can't get a consistent bead profile if you have wire feeding issues (addressed in #3 above), proper technique also plays a role in good bead profile. It's recommended to use a stringer bead. Whipping or back stitching slows down travel speed and increases heat input, which may result in lack of penetration or fusion. Push techniques should be used while maintaining a consistent weld puddle size and shape. The welding arc should be kept on the leading edge of the puddle, since allowing the arc to fall back into the puddle can result in problems with lack of fusion.
Porosity: Almost every operator at some point has dealt with porosity when welding aluminum. Porosity is most often caused by a lack of proper cleaning of the base material or using weld parameters that are too cold. Using a pulsed MIG process rather than a short-circuit process can reduce porosity on aluminum. Porosity may also be caused by a lack of shielding gas, which may be the result of improper settings on the equipment, a hole in the gun liner/torch hose or wind blowing the shielding gas away. One indicator of shielding gas problems is a very black and sooty looking weld.
Distortion and warpage: If you're experiencing distortion or warpage when welding aluminum, it often comes down to heat input and technique. Lower the heat input by welding at the fastest travel speeds possible. Minimize weaving and whipping techniques, and use weld settings rather than technique to control puddle size and fluidity.
For more welding gun exporterinformation, please contact us. We will provide professional answers.