Effect of Cold Rolling on the Microstructure and Texture of Selective Laser Melting Built Fe-Ni-Cr Steel.

Incoloy 800 is an iron-based Ni-Cr super-austenitic stainless steel that finds applications involving exposure to high temperatures and corrosive environments. This study aims to investigate the effect of cold rolling on the microstructure, texture and hardness of Incoloy 800 fabricated by selective laser melting. Rectangular specimens of 100 × 20 × 5 mm were printed in the vertical build orientation. The as-built alloy was subjected to unidirectional cold rolling along the long transverse plane to achieve thickness reductions of 20, 40, 60 and 80%. Optical and scanning electron microscopy were used to observe the microstructure. EDS was used to find the elemental composition. An x-ray goniometer was used to measure the bulk texture. Vickers hardness test was performed to measure the hardness. The optical micrographs of the as-built sample revealed a laser scan track pattern on the top surface, whereas the short and long transverse sections revealed typical fish-scale morphology with overlapping melt pool boundaries. Melt pool widening was observed upon increasing the rolling percentage. Scanning electron microscope revealed three types of grain morphology–cellular, elongated cellular and columnar. X-ray diffraction revealed the presence of austenite (γ) phase. The as-built alloy showed cube, goss and copper texture components. The sample rolled to 80% reduction showed strong brass and a weakened goss component. The 80% cold-rolled sample showed 42 and 116% higher hardness than the as-built condition and as-cast condition, respectively, due to strain hardening. [ABSTRACT FROM AUTHOR]