Weld Mold® 955 MCT
Weld Mold 955MCT is a superior mold steel rod, developed to provide the plastic injection mold industry as a TIG welding rod for NAK-55 Mold steel. Weld Mold 955MCT is a perfect match to NAK-55. Matching the base material is of the utmost importance, particularly when the weld deposit and adjacent areas of the mold/die are to be etched or grained. Weld Mold 955MCT copper coated bare rods have a very carefully balanced analysis which provide a weld deposit that can be applied time after time without porosity, cracks or flaws when correct welding procedures are followed. When polished weld deposits take on a very high luster.
Weld Mold 955MCT bare rod is used for the repair and buildup of NAK-55 superior mold steel dies in the automotive, home appliance, computer, camera, electronic and plastic film extrusion industries. It may also be used to overlay working areas of lesser alloys to provide a more wear resistant surface.
- All areas to be welded must be clean and free of all cracks, fatigued metal, sharp radii, surface treatment i.e. nitriding and foreign material.
- Preheat the parent die to 650° F and maintain this temperature during the entire welding sequence. Peen weld deposits when necessary and when practical. Upon completion of welding, immediately temper the mold/die at 850°/950° F. for one hour at temperature to relieve stresses. Do not allow the mold/die to cool between welding and post heat treatment. Upon completion of temper, cover and slow cool in still air to ambient temperature. It should be noted that when using a gas burner, always heat from the bottom of the mold or die.
- Weld Mold 955MCT is applied by the G.T.A. "TIG" method using direct current (D.C.), straight polarity (work positive) and argon shielding gas.
- Make sure the welding torch has not been used to weld any copper or aluminum base alloys. If so, replace the tungsten, cup, gas diffuser and collet with new spare parts.
- Weld Mold 955MCT is applied using the stringer bead technique; do not puddle the weld bead. Use the smallest filler rod, the smallest diameter tungsten.
Re-aging of 955MCT is recommended when the surface of the welded mold is to be etched, textured or polished. To completely restore hardness (40 RC) and other metallurgical properties; charge mold into furnace and heat to 932°F. After the mold reaches 932°F hold at temperature for five hours. Remove from furnace, cover and slow cool in still air to ambient temperature.