Laser repair welding of molds with various pulse shapes

Repair welding of cold-work tool steels with conventional methods is very difficult due to cracking during remelting or cladding and is generally performed with preheating. As an alternative, repair welding with laser technology has recently been used. This paper presents the influence of different pulse shapes on welding of such tools with the pulsed Nd:YAG laser. Repair welding tests were carried out on AISI D2 tool steel, quenched and tempered to hardness of 56 HRc, followed by microstructural 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. ~elika za rad na hladno konvencionalnim metodama je vrlo te{ko zbog pukotina nastalih tokom pretaljivanja i navarivanja i op}enito vr{i se uz predgrijavanje. U posljednje vrijeme se kao alternativna metoda koristi reparaturno zavarivanje upotrebom laserske tehnologije. Ovaj rad predstavlja utjecaj razli~itih oblika impulsa na zavarivanje alatnih ~elika s pulsnim laserom Nd:YAG. Reparaturno zavarivanje testirano je na alatnom ~eliku AISI D2,