Influence of Carbon Content on Micro-stresses in Cemented Carbide

Motivation

WC-Co-based carbide is one of the most important tool materials. In the production of a car, more than 50 manufacturing steps involving carbide are necessary. An important aspect is understanding the formation of type II residual stresses. These residual stresses, which act at the grain level, not only influence subsequent manufacturing steps in tool production, but also overlap with the operating loads of carbide products, thus impairing their performance. The carbon content is significant for the microstructure and properties of WC-Co carbides. The research approach of the project is based on experimental and numerical work, all of which aims to quantify the influence of the carbon content on the microstructure and the process-related internal stresses. The project will result in an experimentally validated simulation chain that will enable an understanding of the individual influences on residual stresses and thus a targeted improvement of carbides by controlling the carbon content within the process window during the manufacture of carbide tools.

Objective and Scope of the Project

The type II residual stresses acting in the structure after sintering of cemented carbide significantly determine both the subsequent manufacturing steps of a tool (e.g., eroding and coating) and the mechanical properties such as strength and toughness. The overarching objective of the research project is therefore to understand and quantitatively determine the influence of carbon content on type II residual stresses in cemented carbide. To this end, a simulation model will be developed and verified using measurements of the average carbon content in cemented carbide on the one hand and residual stress measurements in cemented carbide on the other. The influence of carbon on residual stresses in cemented carbide will then be quantitatively investigated using computational studies.