Improving the application behavior of hot-forming tools through the nitriding-compatible selection of hot-work tool steels

Challenge

Forging tools are subjected to a complex load spectrum, which leads to increased wear and consequently to an increase in component imprecson as well as a shorter service life of the forming tools. One possibility for reducing wear is (plasma) nitriding. Within the framework of this project, a fundamental understanding of the cause-effect relationships was obtained.

Solution

The institutes have performed nitriding of materials with different chemical compositions, fundamentally characterized them metallographically and subjected them to practical model tests. These included static annealing tests, dynamic thermal-shock tests and series-forging tests. This enabled findings to be obtained on the cracking and oxidation behavior as well as the loss of hardness in the nitriding zone. In order to be able to evaluate the cracking behavior in the edge zone in more detail, the investigations were extended to include microstructure and residual-stress measurements.

Added value

Towards the end of the project, it became apparent that, in addition to the classic hot-work tool steels (1.2343 and 1.2367), the nitriding steel 1.8550 and the cold-work tool steels 1.2362 and 1.2363 also exhibit target-oriented properties. For this reason, they will be used in further validation tests in industrial trials in order to be able to assess a realistic reduction in costs in the production process.