Imperfections in laser clading with powder and wire fillers

Abstract

Laser cladding has been increasing in laser job shops both for component repair and manufacture. The process is quite mature nowadays, from a scientific approach, but companies need manufacturing guidelines and procedures to minimise the occurrence of defects and improve service quality and productivity. Typical imperfections occurring in laser clads can be divided into two major groups: shape and microstructural defects. The first group includes the contact angle of the clad track with the substrate surface and the total height of the clad including penetration. In the second group are considered lack of fusion, porosity and cracks. It is not clear to which extent the use of powder or wire as filler materials influence defect formation, though it is well known that these are mostly related to material properties and operational procedures. This paper presents the work done in laser cladding using filler wire and powder in real productive environment in job shop cases on different substrates: AISI 316 stainless steel, H13 and P20 tool steels. An overview of the defects that are more prone to appear in these materials is presented and strategies to minimise their occurrence proposed.