Mechanical Properties Of 316L Stainless Steel Research Articles

Influence of compound field-assisted on the mechanical properties of 316L stainless steel fabricated by laser powder bed fusion

The advantages of field-assisted laser additive manufacturing in optimizing microstructure and performance are increasingly recognized. Recently, we investigated the effects of acoustic field (AF) assisted laser powder bed fusion (LPBF) on the mechanical properties of 316L stainless steel (SS) and 316L SS/WC composite materials. Due to the effects of acoustic streaming and cavitation, acoustic field-assisted LPBF achieved optimized mechanical properties. Building on our previous research on AF-assisted LPBF, we introduced magnetic field (MF) and compound field (MF+AF) to study their effects on the microstructure and mechanical properties of 316L SS, 1 wt% and 3 wt% WC/316L SS. Application of the MF induces induced currents in the melt pool due to the Thomson-Seebek effect. The interaction between the MF and induced currents generates thermoelectric magnetic force (TEMF) and thermoelectric magnetic convection (TEMC), which inhibit the growth of columnar grains and enhance mass and heat transfer in the melt pool. Compound field-assisted LPBF reduced the dislocation density of 316L SS, refined grain size, alleviated the concentration distribution of grain orientation, and the ultimate tensile strength of the samples reached 777 MPa and the elongation at break reached 57.5%. Interestingly, for WC/316L SS, both MF and compound field resulted in a decrease in tensile performance, with ultimate tensile strengths as low as 677 MPa and elongations at break as low as 25.1%. This is because the MF affects the uniform distribution of WC particles, causing significant agglomeration and severe unmelted defects in the composite material, leading to a decrease in tensile performance.

Effect of Cold Mechanical Process on the Mechanical Properties of 316L Stainless Steel for Medical Implant Application

The objective of this research was to study the mechanical properties of cold-worked 316L stainless steel (SS) after it has undergone the cold mechanical process. A 316L SS sheet was cold-rolled until a reduction in thickness was within the range of 10% to 50%. The sheet was then plastically deformed into a U-bend shape using a universal testing machine equipped with a bending jig. The mechanical properties of the cold-rolled and U-bend steel were analysed using a tensile, 3-point bending, and microhardness tests. It was found that the rolling and bending processes produced such amount of plastic strain that affect the mechanical properties of the 316L SS. The strength of the cold-rolled, U-bend 316L SS increased gradually as the cold reduction was raised above 10%, which was mainly due to the strain hardening effects. The ultimate strength of the U-bend steel increased gradually compared to the cold-rolled steel for each stage of the cold reduction process. On the other hand, the microhardness of the U-bend steel increased rapidly after a cold reduction up to 10%, and the value increased slightly after a cold reduction of 30%. This study indicated that the mechanical properties of 316L SS can be increased by using a combination of the cold rolling and bending processes.

Tensile behavior of hydrogen-charged 316L stainless steel at elevated temperatures

We examined the high-temperature tensile properties of 316L austenite stainless steel (SS) cathodically charged with hydrogen (H) and discussed how the H distribution, strain rate, and temperature range affected the mechanical properties of 316L SS at elevated temperatures, with particular focus on dynamic strain aging (DSA). A preheat treatment was applied prior to each high-temperature tensile test to lessen the H gradient on the outer surface of the specimen. DSA, manifested by serrations in the stress–strain curve, was observed at temperatures between 400 and 500°C and was analyzed using strain-rate sensitivity, dynamic strain–hardening stress, and the temperature dependence of critical serration strain. In particular, this study confined its scope to the influence of H in the range of a few tens of parts per million.