Creation of a diffusional aluminum layer on the narrow walls of continuous-casting molds

Abstract

To extend the working life of molds in continuous-casting machines, diffusional aluminum layers (thickness around 1.5 mm) are sprayed on their narrow walls, made of M1 copper and MN2.5KoKrKh copper alloy, with subsequent diffusional annealing at t = 800°C for 10 h in an oxidative atmosphere. At the surface of M1 copper, a strengthening diffusional aluminum layer of thickness up to 1.5 mm is formed; at the surface of MN2.5KoKrKh copper alloy, the layer thickness is 0.6–1.4 mm. This difference may be attributed to the role of the alloying elements in slowing the diffusion process, with subsequent heat treatment. The performance of the diffusional layer may be assessed in terms of its thickness and microhardness. Analysis of coated samples indicates that the application of a sprayed aluminum coating to the narrow mold walls is expedient, with subsequent heat treatment in a protective atmosphere, in corrected conditions. In tests of the coated mold, the condition of the walls should be assessed, and the quality of the cast metal must be monitored.