Possibility of introducing laser surfacing into maintenance service of die-casting dies

The shape and manufacturing of tools for die casting of aluminium and magnesium alloys are usually extremely exacting and therefore very expensive. In a die-casting process, these tools are subjected to strong thermo-mechanical loads. From the economic point of view the operation life of dies is extremely important to the price of the castings. It has been proved that by a regular maintenance of die parts the life time of dies can be successfully extended. The aim of the investigation was to find a fast, efficient and cost-effective repair procedure for worn surfaces of vital parts of dies made of maraging steels. In this paper, results of CO2 laser repair surfacing of maraging steel with a Ni–Co–Mo alloy similar to the maraging steel, are reported. The surfaced specimens were also post-weld heat treated. The results are based on microstructural analyses of the laser-surfaced specimens and on analyses of the micro-hardness performed after surfacing and after post-weld heat treatment and are supported by analysis of residual stresses.