Analysis of the discharge pulse-dependent surface integrity of spark eroded die inserts made of hard metal and their effects on the tribological properties and the resulting fatigue behaviour

Due to their high wear resistance and increased compressive strength, carbides have a growing potential as a tool material in forming technology. They are characterized by an increased hardness compared to steel materials and at the same time an increased flexural strength compared to ceramics. In this context, the flexural strength is an important material parameter for tool design, since bending stresses are often critical for failure.

Due to the specific material properties - difficult machinability but also electrical conductivity - spark erosion machining is a key technology for the shaping production of carbide die inserts. However, machined carbide tools often show a load capacity that falls short of expectations. The reason for this is assumed to be that machining has not yet been researched and developed to such an extent that the process-related properties of the tool surfaces meet the requirements derived from the requirement profile. On the other hand, our own preliminary work shows that the final component strength can be increased specifically and significantly by the correct process design of the entire process chain. The objective of the project includes the scientifically founded and structured analysis of the influence of the discharge pulse-dependent surface integrity exclusively of spark erosion (macro sink erosion) on the resulting tribological and mechanical component behaviour of two representative carbide materials. These are fine-grained versions with normal binder phase content and a variant that is described as quasi binder-free. The generated surface integrity is to be correlated with the introduced energy on the one hand and with the mechanical component behaviour on the other hand.