Integrative cutting solutions to produce high performance automotive components with high-Mn steel sheet (iCut)

Abstract

The high mechanical strength of AHSS makes them especially susceptible to premature failure if defects are introduced in structural parts as a result of non-optimised cutting processes. The exceptional combination of strength and ductility of high Mn steels (HMnS) makes them exceptional candidates for parts requiring high fatigue resistance, even when defects are present from the processing steps. Currently, there is a major lack of knowledge about the effects of the cutting processes on the mechanical properties and formability of HMnS. This hampers their extensive industrial application because non-optimized cutting could lead to dramatic reduction of part performance. A detailed investigation regarding the quality of the cut edge, which determines fatigue and delayed fracture resistance, is required to face the industrial implementation of HMnS in structural vehicle parts. Moreover, the costs associated with cutting high strength sheets, as well as the environmental impact of the use of HMnS steels, have to be considered before industrial implementation. Press cutting is the most efficient cutting process but tool durability has a big impact on process efficiency and has to be assessed to develop competitive industrial process. A rational evaluation will be performed based on LCA of the substitution of currently used steels in the car body by TWIP steels. Thus, the objective of iCut is to provide the clues to overcome the detrimental effects of the imperfections, introduced in cut edge during cutting processes, on the fatigue life, H-embrittlement sensitivity and formability of sheared areas of HMnS sheets. The cutting parameters and cutting technology which will allow producing high performance HMnS parts will be determined. Different cutting technologies will be studied, looking at process competitiveness and LCA evaluation. For press cutting, which is currently considered the most competitive cutting technology, tool durability and the effect of tool wear on the evolution of the sheet edge quality will be of special interest. The scientific approach will be an integrative one investigating the HMnS microstructure, the effect of cutting process on shear edge quality and tooling performance. RFCS Programme: iCut is a research project funded by the program RFCS, Research Fund for Coal and Steel of the European Commission. The RFCS supports research projects in coal and steel sectors. These projects cover: production processes; application, utilisation and conversion of resources; safety at work; environmental protection and reducing CO2 emissions from coal use and steel production.