A wear ring for a piston of a die-casting apparatus comprises an annular body having a gap extending therethrough. The gap is configured to define at least two circumferentially offset pairs of circumferentially spaced apart facing surfaces. The facing surfaces of each pair are angled and configured to contact each other in a flush manner when the wear ring is circumferentially compressed.

A process for forming a high temperature single crystal canted spring is provided. In one embodiment, the process includes fabricating configurations of a rapid prototype spring to fabricate a sacrificial mold pattern to create a ceramic mold and casting a canted coiled spring to form at least one canted coil spring configuration based on the ceramic mold. The high temperature single crystal canted spring is formed from a nickel-based alloy containing rhenium using the at least one coil spring configuration.

An assembly for electropolishing metal surfaces by means of particles of solid electrolytes in a gaseous environment. According to one embodiment the assembly includes a container and a housing element configured to house at least two metal parts, so as to contain the parts avoiding that they can go out during the electropolish process and at the same time allowing that they can have a given movement within the housing element and at the same time endow them with electrical connectivity by means of a first electrode and a second electrode that are coupled to an electrical source 3. The assembly also includes means to produce a relative movement between the particles of solid electrolytes and the at least two metal parts.