The effect of annealing temperature on the physical and mechanical properties of stainless steel 316L for stent application

A comparative study on mechanical properties and microstructure of 316L austenitic stainless steel annealed in different temperatures were presented. The objective of this study was to get the optimum annealing temperature for austenitic stainless steel 316L for stent application in coronary heart disease. Five groups of specimens (ASTM E8-2004) were annealed in the electric furnace (Ellite Thermal System Ltd., UK) at temperature 1000°C, 1050°C, 1100°C, 1150°C, and 1200°C using a heating rate of 5°C/min with 30 minutes holding time. The heat-treated austenitic stainless steel 316L was cooled to room temperature by slow furnace cooling then collected and characterized. The microstructure evolution of every sample was observed using SEM. The hardness of the sample was measured using Vickers micro hardness test. The universal testing machine was used to measure the tensile strength and elongation of every sample. The results shown that the biggest elongation of austenitic stainless steel 316L is obtained when the material is annealed at temperature between 1050 to 1150°C.