Experimental and numerical investigation of 17–4PH stainless steel fabricated by laser powder bed fusion and hot isostatic pressing

Abstract

Meticulous design and optimization of additive manufacturing (AM) are essential for obtaining high-quality metallic products, particularly using laser powder bed fusion (L-PBF). However, its potential in applications is limited because of the lack of understanding of AM. This makes the process parameter optimization time and cost-consuming. Here, the L-PBF process is employed to minimize defects and enhance the mechanical properties of 17–4PH stainless steel specimens, coupled with modeling. The optimal manufacturing parameters were determined by evaluating the relative densities of the as-built parts and thermal deformation. Either high or low energy densities resulted in high porosity and a higher energy density results in greater thermal deformation, attributed to the high mismatch in thermal expansion, while the surface roughness of as-built products is not as good as commercially available products. The hot isostatic pressing process improved the mechanical properties of the printed product by reducing the porosity and recrystallizing microstructures.

Keywords

• laser powder bed fusion
• 17–4PH stainless steel
• process analysis
• thermomechanical analysis
• thermal deformation
• porosity