Innovative reconsolidation of carbon steel machining swarf by laser metal deposition

The concept of widespread recycling of metals in order to save cost, energy and ecological damage is gaining importance and this necessitates not simply disposing of machining waste. In this work a new way of reconstituting chips/swarf into a usable solid structure is explored by using them in place of metal powder in laser direct metal deposition. Samples of carbon steel machining swarf in three size ranges are reconstituted and the final structural characteristics like clad dimension, microstructure and physical properties are analysed. The results show that it is possible to reproduce a material that has full density, fine microstructure and no significant contamination from an unprecedented size and shape of particles. As general trends, individual deposition tracks become lower, wider and less hard as particle size increases. This work shows that the laser deposition process can be used with a larger range of particle geometries than previously considered and this could be the point leading to a new ‘local’ recycling method.