| Lincoln Electric Cast Iron and Aluminum Arc Welding Electrodes

GUIDELINES FOR WELDING CAST

IRON (CONT.)

good procedures are followed. If the casting must be water tight, this can be a problem. However, leaking can usually be eliminated with some sort of sealing compound or they may rust shut very soon after being returned to service.

The Studding Method - One method used to repair major breaks in large castings is to drill and tap holes over the beveled surface area. Screw studs into the holes leaving 3/16” (4.8mm) to 1/4” (6.4mm) of the stud above the surface. Then, using the standard methods and electrodes described here, weld the studs in place and cover the entire surface of the break with weld deposit. Once a good weld deposit layer is made, the two sides of the crack can be welded together with more conventional methods. However, overheating the casting area must still be avoided.

In cases of severe damage, use of mild steel plates sometimes produces good results. To do this, cut out the damaged area. Fit a piece of mild steel of the appropriate size in the damaged area and weld the steel to the cast iron. Use the welding methods and electrodes used to weld cast iron to cast iron.

ALUMINUM ARC WELDING ELECTRODES

PROCEDURES - USE ELECTRODE POSITIVE (DC+)

Hold a short arc with the coating almost touching the molten pool. Use the highest current possible without melting the edges back too far or burning through.

The high melting rate of the aluminum electrode combined with the high conductivity of the aluminum plate chills the weld rapidly. Therefore, to keep the pool molten long enough to form well-shaped beads preheating to 600-700°F is often needed.

Strike the electrode by “scratching”. Strike the arc in the crater of the previous bead, then quickly move back along the weld for 1/2” (12.7mm) and proceed as usual. Be sure the crater is completely remelted.

Hold the electrode almost perpendicular to the work at all times to obtain even melt-off of the flux. Point the arc directly into the joint so both edges are properly and uniformly heated.

For tacking, use currents about 20% above the maximum current listed in the recommended ranges. Use a short arc with a rotary motion.

Remove the last traces of slag with warm water and a wire brush or by soaking the weld in a 5% nitric acid or 10% warm sulfuric acid solution followed by a warm water rinse.

WARNING: Be careful with these strong acid solutions. Wear safety glasses and avoid contact with skin or clothing.

Avoid out-of-position welding.

Aluminweld can also be used as a filler rod with a carbon arc torch.

Customer Assistance Policy

The business of The Lincoln Electric Company is manufacturing and selling high quality welding equipment, consumables, and cutting equipment. Our challenge is to meet the needs of our customers and to exceed their expectations. On occasion, purchasers may ask Lincoln Electric for advice or information about their use of our products. We respond to our customers based on the best information in our possession at that time. Lincoln Electric is not in a position to warrant or guarantee such advice, and assumes no liability, with respect to such information or advice. We expressly disclaim any warranty of any kind, including any warranty of fitness for any customer’s particular purpose, with respect to such information or advice. As a matter of practical consideration, we also cannot assume any responsibility for updating or correcting any such information or advice once it has been given, nor does the provision of infor- mation or advice create, expand or alter any warranty with respect to the sale of our products.

Lincoln Electric is a responsive manufacturer, but the selection and use of specific products sold by Lincoln Electric is solely within the control of, and remains the sole responsibility of the customer. Many variables beyond the control of Lincoln Electric affect the results obtained in applying these type of fabrication methods and service requirements.

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