Product Code: ICAL09_P126

The Influence of Laser Pulse Shape in Repair Welding of Tool Steels
Authors:
Matej Pleterski, Faculty of Mechanical Engineering, University of Ljubljana; Ljubljana Slovinia
Janez Tusek, Faculty of Mechanical Engineering, University of Ljubljana; Ljubljana Slovinia
Damjan Klobcar, Faculty of Mechanical Engineering, University of Ljubljana; Ljubljana Slovinia
Ladislav Kosec, Faculty of Natural Sciences and Engineering, University of Ljubljana; Ljubljana Slovinia
Mitja Muhic, Tkc D. O. O.; Ljubljana Slovinia
Presented at ICALEO 2009

The majority of tool steels are commonly considered as non-weldable, because of their high carbon and high alloy elements content. Repair welding of such steels with conventional methods is very difficult due to cracking during remelting or cladding and is generally performed with preheating. Repair welding with laser technology offers, besides its common benefits, also a possibility of tool repair without preheating. This paper presents the influence of different pulse shapes on welding of high carbon, high chromium tool steel with the pulsed Nd:YAG laser. Repair welding tests were carried out on AISI D2 tool steel which is commonly used for deep drawing, blanking, forming and thread rolling dies; shear and granulator blades and high wear resistant and intricate moulds for plastic injection. The steel specimens were quenched and tempered to hardness of 56 HRc, followed by microstructural analysis, microhardness analysis and investigation of defects with scanning electron microscopy. Test results suggest that it is possible to obtain sound welds without preheating, with the right selection of welding parameters and appropriate pulse shape.