Analysis of a forging die wear by 3D reverse scanning combined with SEM and hardness tests

The work concerns the application of non-contact measurement 3D scanning techniques in conjunction with a study of the microstructure of a forging die (made of W360 steel) for the production of an engine valve (made of NCF 3015 steel) in a hot die forging process in order to analyse the changes in the working surface of the tools and identify the destructive mechanisms. The detailed analysis presented in this paper examines the possibility of using 3D reverse engineering techniques for a direct quality control and examination of the changes in the surface layer geometry of the forging dies, based on the measurement of the geometry changes for cyclically collected forgings. The selected area of the valve forgings cyclically retrieved from the forging process was scanned with the use of an intermediate scanning method - reverse 3D scanning. On this basis, an analysis of the progressive material growth on the selected surface of the forgings was made, which also meant a loss of material on the tools. The performed analyses showed a good agreement of the geometrical properties of the surfaces (of the selected forgings representing the proceeding wear of the tool) and the geometrical defect of the working impression of the tool, based on the direct measurements during the production process. The reverse 3D scanning method developed by the authors has been repeatedly verified by them, which is confirmed by numerous studies and applications. The obtained results combined with SEM analyses and microhardness measurements enable a fast analysis of the forging tool life with respect to the quality and quantity (of material defect), which, in consequence, leads to significant economical savings.