5-5. GMAW (MIG) Aluminum Welding Hints

Here are several hints to help you be more successful with your new aluminum feed system.

MIG welding aluminum requires different techniques than MIG welding mild steel.

A. Before You Start Welding

SMaterial thickness that can be welded with MIG process or aluminum are 14 ga. [0.074 in. (1.9 mm)] or heavier. (How heavy depends on the output capacity of the welder being used.) To MIG weld aluminum thinner than 14 ga. either specialized pulsed MIG or AC TIG welding equipment may be necessary.

SThe removal of lubricants from the aluminum base material may be necessary. Consult with your local welding distributor for their recommendation on aluminum cleaners.

SOxide removal should be done after degreasing. This should be done with a stainless steel wire brush. This can be done with a hand wire brush or with a cup wire brush. If a power wire brush is used, keep the RPM’s and pressures low to reduce smearing the surface of the material, which could entrap oxides and impurities under the surface. Always use a wire brush that is used only on aluminum to keep from contaminating the base material.

SContact you local welding distributor or aluminum filler metal representative for recommendations on wire alloys that fit your application. Know the alloy of your base aluminum and what conditions the finished part will be subjected to. The two most readily available aluminum filler wires are ER4043 and ER5356.

B. Welding Techniques

SMake sure the welding power source is set up to weld DCEP (DC Electrode Positive).

SFor MIG welding aluminum you need to use a 10 to 15 degree push travel angle (tip and nozzle pointing in the direction of travel). See Figure 5-1.

Side View Of Gun Tip Angle

10°-15°10°-15°

Direction Of Welding

 

Forehand (Push)

Backhand (Drag)

Technique

Technique

Figure 5-1. Gun Tip Angle

SPulling or using a drag angle will produce porous, dirty welds due to a lack of gas coverage.

SSpray transfer is the desired mode of metal transfer for welding aluminum. The spray transfer is a very smooth transfer of molten metal droplets from the end of the electrode to the molten pool. The droplets crossing the arc are smaller in diameter than the electrode. There is no short-circuiting in spray transfer. With spray transfer, the deposition rate and efficiency is relatively high. The arc is very smooth, stable, and stiff and the weld bead has a nice appearance and a good wash into the sides. In the spray transfer, a large amount of heat is involved which creates a large pool with good penetration that can be difficult to control and cannot be used on materials thinner than 14 ga. This transfer will produce a hissing sound and no spatter.

SThe short arc transfer on aluminum produces poor cleaning action, poor tie-in at the edges of the weld, and large amounts of spatter and smoke.

SThe reflective heat and weld puddle that is present when MIG welding aluminum is very hot. Holding the tip closer than 3/4 in. could lead to the wire burning back to the contact tip and other feeding problems.

SThe most common shielding gas for MIG welding aluminum is 100% argon. Flow rates of 20 to 30 CFH [cubic feet per hour (0.57 to 0.85 m3/hr)] are acceptable. C25 or argon CO2 shielding gases are not acceptable.

OM-230 261 Page 18

Page 22
Image 22
Hobart Welding Products DP 3035-10 manual Gmaw MIG Aluminum Welding Hints, Before You Start Welding, Welding Techniques

DP 3035-10, DP 3035-20 specifications

Hobart Welding Products has established a reputation for manufacturing high-quality welding equipment, and their DP 3035-20 and DP 3035-10 models are prime examples of their innovative approach to welding technology. Designed to cater to a variety of welding needs, these products are engineered to enhance performance and provide durability in various industrial applications.

One of the main features of the Hobart DP 3035-20 and DP 3035-10 is their versatility. Both models are suitable for multiple welding processes, including MIG, TIG, and stick welding. This adaptability makes them ideal for fabricators, metalworkers, and DIY enthusiasts who require a reliable machine that can handle different types of materials and welding techniques. The machines are designed to work seamlessly with a range of metals, including steel, aluminum, and stainless steel, ensuring comprehensive usability across various projects.

Another remarkable aspect of these models is their advanced technology. Hobart incorporates cutting-edge inverter technology in both the DP 3035-20 and DP 3035-10, enabling these machines to deliver precise and consistent power output. This technology improves energy efficiency, reduces the overall weight of the welder, and enhances portability, making it easier for users to transport their equipment to job sites. Users can expect stable arc performance even at low amperage settings, further expanding their welding capabilities.

The user-friendly interface is another characteristic that sets the Hobart DP 3035 series apart. With clearly marked controls and a digital display, users can easily adjust settings for output and wire feed speed, facilitating an intuitive welding experience. Additionally, the process of switching between different welding modes is streamlined, allowing users to focus on their work without the hassle of complicated setups.

Durability is a priority for Hobart, and these welders are built to withstand the rigors of daily use. Featuring robust construction and high-grade components, the DP 3035-20 and DP 3035-10 are designed to provide long-lasting performance. They also come with built-in safety features such as thermal overload protection, ensuring reliable operation even under demanding conditions.

In conclusion, the Hobart Welding Products DP 3035-20 and DP 3035-10 models exemplify excellence in welding technology. With their versatile applications, advanced inverter technology, user-friendly design, and durable construction, these welders are well-equipped to meet the demands of modern welding tasks. Whether you are a professional tradesperson or a passionate hobbyist, these machines offer the reliability and performance that you need to achieve your welding goals.