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SOLUTIONS: Cast Iron

Arc welding of cast iron Below is a short description of the cast iron electrodes Unitor NICKEL333N and Unitor NIFE-334N to help you select the correct electrode for the work. Complete data on these electrodes are found in the section “Technical Data for Consumables”. Remember that cold welding of cast iron can only be done by electric arc welding.

contact surface indicates the most suitable electrode for the binding layer for this particular base metal. For information on porosity, it's causes and correction; see under heading "Poor Welds".

Unitor NICKEL-333N

For use on old, oil-impregnated cast iron and on thin material dimensions. Use this electrode to “butter” the sides of oily cast iron to seal the surface. Then finish the filling-up to join the parts together with Unitor NIFE-334N, which has greater tensile strength. Do not deposit more than maximum two layers for NICKEL-333N.

Unitor NIFE-334N

To be used on cast iron that takes strain, vibrations and sudden loads. Also to be used for joining cast iron to steel, copper alloys and stainless steel. NIFE-334N is used for multi-bead welding on heavy gauge material. It has greater tensile strength than NICKEL-333N.

Electrode binding test

Grind off a small area of the material close to the welding zone. Select a 3.2 mm electrode of NICKEL-333N and NIFE-334N, and deposit a 4-5 cm bead with each of them without weaving. Use 100 Amps and the correct polarity. Use a hammer and chisel to remove the beads. The bead which exhibits the least porosity on the

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Hot welding

In hot arc welding the part must first be evenly heated to approximately 500°C. Especially if the casting to be welded has any appreciable material thickness it is important that the preheating proceeds slowly. Cast iron has a low coefficient of thermal conductivity, and demands care in preheating. Too quick heating can cause tension cracks. The temperature must be maintained throughout the welding operation. As the means for preheating on board will normally be limited to the welding torch, it means that only smaller parts, and which can be dismantled and brought into the workshop can be hot welded on board.

When hot welding cast iron the temperature of the workpiece must be

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