Votes - 2, Average rating: 4 ( )

Manafacture: Hobart Welding Products File size: 780.43 kb File name: Language of manual:

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. . Contact 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 . Make sure the welding power source is set up to weld DCEP (DC Electrode Positive). . For 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. 10°-15° Side View Of Gun Tip Angle 10°-15° Direction Of Welding Forehand (Push) Backhand (Drag) Technique Technique Figure 5-1. Gun Tip Angle . Pulling or using a drag angle will produce porous, dirty welds due to a lack of gas coverage. . Spray 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. . The 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. . The 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. . The 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-226 857 Page 19 . Maintain a 3/4 in. (19 mm) tip-to-work distance, and have the contact tip recessed approximately 1/8 in. inside the nozzle if possible. See Figure 5-2. CCCCCCCCCCCCCCCCCCCCEEEEEEGas Nozzle Contact Tube Recessed 1/8 in. (3.2 mm) Inside The Nozzle Contact Tip To Work Distance 3/4 in. (19 mm) Figure 5-2. Contact Tube Position And Tip-To-Work Distance . Avoid large weave beads on aluminum. If larger fillet welds are needed, multiple pass straight beads will provide better appearance and have less chance of cold lapping, burn through, and other weld defects. . It will be necessary to increase torch travel speed as the base material becomes heated during the welding process. . The skill level of the operator, joint types, fit up, and positions, as well as the welding power supply will all have a great influence on the weldability of the aluminum and your success. C. Common Problems/Troubleshooting . Burn through (melt through) caused by over heating the base material. 1. Increase travel speed. Make shorter welds. 2. Move around on part, spreading out the heat. 3. Use thicker material, change joint design or welding process to AC TIG. 4. Eliminate or reduce gaps. . Dirty welds. 1. Use push angle instead of drag technique. 2. Increase voltage to get into spray transfer. 3. Use proper base metal cleaning techniques (stainless steel brush). 4. Check for proper shielding gas and wire alloy type. . Wire burns back to contact tip during or at the end of the weld. 1. Maintain a 3/4 in. (19 mm) tip-to-work distance. 2. Check to make sure the contact tip size, drive rolls and gun liner match the wire diameter that you are using. (Sometimes an oversized tip can be used. The ID should only be one size larger than the wire diameter.) . Wire “bird nests” (piles up) in front of inlet guide on gun. 1. Check and adjust drive roll tension. 2. Check to make sure drive rolls match wire diameter. 3. Replace contact tip if fouled or plugged.(Sometimes an oversized tip can be used. The ID should only be one size larger than the wire diameter.) OM-226 857 Page 20 SECTION 6 . ELECTRICAL DIAGRAMS 186 451 Figure 6-1. Circuit Diagram OM-226 857 Page 21 OM-226 857 Page 22 SECTION 7 . PARTS LIST Hardware is common and not available unless listed. 801 900-D 3 2 30 26 29 31 27 15 28 25 24 23 18 17 16 13 11 10 4 9 8 7 6 5 4 2 1 38 39 40 41 37 36 34 35 33 32 19 22 21 20 12 14 Figure 7-1. Complete Assembly For Spool Gun 3035-20 Item Dia. Part No. Mkgs. No. Description Quantity Figure 7-1. Complete Assembly for Spool Gun 3035-20 ... 1. . . PB1. . . . . 186 416. . ...

Download now

Please, enter two numbers from picture: