Evaluating the properties of products fabricated from commercial steel powders using the selective laser micro-welding rapid manufacturing technique

Abstract

Selective laser micro-welding (SLMW) is a recent rapid manufacturing technique that produces metal parts through the use of a laser beam that selectively scans over the powder layers and fully melts and micro-welds the metallic particles. The advantage of SLMW is that any type of commercial steel alloys or other metal powders can be used to build parts in a single step without the need to add low melting point additives to join the particles as in the former SLS process. In this study, two types of low cost general purpose powders were evaluated as the raw materials for the selective laser micro-welding (SLMW): one powder is AISI304 stainless steel powder from Hoganas, Belgium (cost = $11/kg) and the other isAISI100510w carbon steel locally produced in-house from scrap steel using gas atomizing then de-oxidizing techniques (cost = $1.2/kg). Twelve sample parts were fabricated using two different laser speeds, 70 and 100 mm/s. Dimensions, density, hardness, tensile and microstructure properties were evaluated. Results showed that both powders successfully produced complete parts with accurate dimensions and fine details. Both microstructure phases were austenite due to the rapid heating and cooling cycles. At the higher speed of 100 mm/s mechanical properties deteriorated because of the porosities inside the structure. Using low cost powders gives more potential for the SLMW to spread as an economical manufacturing process in the near future.