Process and parameters for laser assisted localised heat treatment in manufacturing applications

Abstract

This paper presents information and results relevant for the development of a laser heat treatment process suitable to improve manufacturing in high strength steel and high strength aluminium alloys. The challenges with manufacturing of such materials include springback effect and localised fracture. The study details heat cycle and their effect in metallurgical state and mechanical properties. Such laser induced heat treatment process is intended to improve the forming behaviour of metal parts in challenging metal forming conditions, in particular for the delay or avoidance of localised fracture. Results for strength, hardness and elongation properties are presented. It was concluded that it is possible to locally modify yield strength and hardness using process duration suitable for industrial applications. Suitable process temperature ranges and target heat cycles were identified. A positive effect of material softening was observed in both hardness and strength properties. However, in some cases a reduction of ductility is apparent which must be considered for targeted industrial applications. The dimension of the heat-affected zone was also considered as design variable for the industrial process development. Preliminary results were obtained in a development forming tool.