Improving the wear resistance of copper tools for pressure die casting by laser melt injection

Abstract

Highly conductive copper alloys are used for various tools in casting and welding technology. In pressure die casting, copper alloys are used for pistons pressing the metal melt into a die. The high thermal conductivity of these alloys allows short process times as a result of high cooling rates. Due to a poor wear resistance, wear occurs on the running surface of the pistons causing the metal melt to spurt out of the shot sleeve. In order to improve the service life of the pistons, a new approach was taken: a reinforcement of the copper alloys with fused tungsten carbide (FTC) particles by laser melt injection (LMI) at high process velocities. FTC provides a hardness between 2700 HV 0.1 and 3500 HV 0.1. During LMI, a melt pool is induced on the substrate by a laser beam and a filler material is injected into this melt pool by a powder nozzle. In contrast to laser cladding, the filler material remains in the solid state and the substrate works as matrix material. Thereby, specific material properties of the substrate—e.g. a high thermal conductivity—can be preserved within the surface layer. It was shown that the FTC particle reinforcement reduced the wear by 69–75%. Abrasion and adhesion were identified as the dominant wear mechanisms. The run-in behavior of FTC particle reinforced and non-reinforced parts was determined.

Effect of build orientation on tribological and flexural properties of FDM-printed composite PLA parts

“…Copper-filled PLA specimen showed one of the highest COF values which is attributed to low wear resistance and high ductility. 54 Lower COF values are recorded in the wet sliding test of copper-filled PLA specimen which can be attributed to good ductility properties and absence of pulled off particles in the wear medium. Bronze-filled PLA specimen had moderate COF value compared to other filler materials in the dry sliding condition.…”

Residual stresses in Cu matrix composite surface deposits after laser melt injection

“…In contrast, the residual strains and stresses in the Cu matrix of the sFTC/bronze composite deposit and the re‐melted bronze samples were measured via neutron diffraction at the beamline SALSA, Institut Laue‐Langevin. [ 17 ] The neutron wavelength was 1.644 Å with the Si (400) monochromator. The gauge volumes for the longitudinal, transversal, and normal directions are 0.6 × 2.0 (//Y) × 0.6, 10.0 (//X) × 0.6 × 0.6, and 10.0 (//X) × 0.6 × 0.6 mm 3 , respectively.…”

Temperature and distortion in laser melt injection of MMC wear-resistant coatings in a copper beryllium alloy

“…LMI is therefore beneficial for a variety of wearexposed tool surfaces, such as casting tools and injection molds, which are often made of copper alloys. LMI with fused tungsten carbide (FTC) particles in the copper alloy Hovadur® CNCS led to a significant improvement in wear resistance against the hardened and gas nitrided steel 1.2343 [2]. Tribological tests for an aluminum bronze and FTC MMC have shown that wear can be reduced by 76% [3].…”