Production of Filler Rod for Repair Welding of ZK51 (ML12) Magnesium Alloy Castings

Abstract

In magnesium alloys castings, the casting defects such as shrinkage porosity often occur. Such defects can be suppressed by repair welding or surfacing using a special filler rod. Unfortunately, in Russia, a low amount of filler rod is consumed. Therefore, domestic enterprises do not manufacture it, limiting themselves to imports or homemade low-quality substitutes. Nevertheless, there is a need for filler rod, and recently it has become unprofitable to replace them with imported materials owing to a significantly increased price. Therefore, there is a need to study the technology of its production to replace imported filler rod with domestic material. Magnesium alloys based on the Mg–Zn–Zr (La, Nd) system SV1, SV122, and ZK51 (ML12) that used as a filler rod for repair welding of ZK51 alloy castings were studied in this work. The samples were obtained by permanent mold casting into aluminum molds followed by hot extrusion into a filler rod with a diameter of 4 mm. It was shown that all the investigated alloys could be obtained in the form of a rod with a diameter of 4 mm. Therefore, the investigated rod samples from the SV122 alloy were used as filler material for repair welding of ZK51 magnesium alloy castings. The weld seam in the T1 condition has an ultimate tensile strength (UTS) about 80% of the UTS of the casting material.