G-TECH 55

Nominally Fe-55% Ni alloy for the repair and joining of cast iron.

The structure depends on the chemical composition and the speed of solidification and subsequent cooling down.

The NiFe weld metals produce higher strength than the pure nickel cast iron types and are therefore preferable for dissimilar joints, higher strength cast irons and spheroidal graphite cast irons.

• EN W.Nr.: 1563:2018 Spheroidal graphite cast irons, 1562:2019-06 Malleable cast irons
• ASTM: A602, A47, A338, A220

In many cases, welding can be performed without preheating; however, for heavy multi-pass deposits or joints with high constraints, preheating between 150-250 °C may be necessary. Prior to welding, surfaces must be prepared by gouging and/or grinding, minimizing heat input to prevent crack propagation. It is essential that the area to be welded is as free from contaminants like sand, oil, grease, paint, or rust as possible. Preheating can be helpful in eliminating oil impregnated in castings to be repaired. If proceeding without preheat, it is preferable to limit the width of the HAZ using low heat input and low interpass temperature welding techniques. Using a fractional welding technique can be advantageous. For welding of thicker sections or with high constraints, preheating in the range of 150-250 °C might be necessary. Additionally, light peening to reduce contraction stresses can be beneficial, but it's crucial not to compromise the ductility of the weld metal. Buttering of the joining faces or sides of the repair cavity is also recommended before completion, regardless of the preheat applied. After welding, gradual cooling of the piece, with insulation if necessary, is highly recommended.