Preliminary Investigation on SLM of ASTM A131 EH36 High Tensile Strength Steel for Shipbuilding Applications
Tor, Shu Beng
Chua, Chee Kai
Lui, Onn Kit Basil
Aziz Amirali Merchant
Date of Issue2014
Proceedings of the 1st International Conference on Progress in Additive Manufacturing (Pro-AM 2014)
School of Mechanical and Aerospace Engineering
Singapore Centre for 3D Printing
In this preliminary investigation of selective laser melting (SLM) of EH36 high tensile strength steel, a 175 W Yb:YAG laser in continuous wave mode was used to produce EH36 test specimens. The laser beam profile follows the Gaussian distribution and has a wavelength of 1.064 nm, with a focaldiameter of 81 µm. The powder layer thickness was set at 50 µm. The stainless steel substrate plate was preheated to 100 °C. The scanning speeds were varied from 260 mm/s to 880 mm/s, and hatch spacing were varied from 0.08 mm to 0.12 mm, to obtain the various energy densities. The highest density value of 7.64 g/cm3 was obtained at an energy density of 92 J/mm3 using parameters of 0.12 mm hatch spacing, powder at 175W, 50 mm layer thickness and 320 mm/s laser scanning speed. Compared to the relative density of the compacted supplied powder (7.83 g/cm3), the results translated to 97.57% fully dense part. Micrographs were obtained using light optical microscopy, which showed slight porosities in the SLM built part. X-ray diffraction and scanning electron microscropy revealed BCC phases and martensitic microstructure respectively.
© 2014 by Research Publishing Services.