Enhancing stainless steel 316L casting with argon gas diffuser: impact on mechanical strength, residual stress, and crystallographic texture

Abstract

ABSTRACT In order to improve the manufacturing of as-cast stainless steel 316 L, controlling the formation of inclusions through the oxidation process is crucial. A research study focused on cleaning liquid medical-grade stainless steel 316 L metal alloy was conducted. The study utilised an Argon gas diffuser installed at the bottom of the furnace. Different furnace capacities were tested during the casting process, with a non-diffuser furnace used as a comparison. Molten metal was poured into a Mold, producing tensile test specimens at temperatures ranging from 1560°C to 1580°C. Fracture observations were carried out using an optical microscope and SEM after the tensile test. XRD observations were also conducted to analyse crystal direction, grain size, and residual stress resulting from variations in the argon gas diffuser’s flow and furnace size. The results showed that the Argon gas diffuser process significantly reduced the formation of oxide inclusions, leading to a substantial increase in the material’s strength. However, a smaller furnace capacity resulted in more porosity. Crystallographic observations indicated that the gas diffuser usage enhanced the material’s yield strength by creating a slip plane perpendicular to the tensile test direction.