Papers by Keyword: 316L Stainless Steel

Abstract: Functionally graded materials represent a promising strategy for locally optimizing component properties while reducing both economic and environmental costs. To date, no study has addressed the development of a compositional gradient between 316L stainless steel and Invar 36 using the Wire Arc Additive Manufacturing (WAAM) process, despite the strong potential of this material combination. Indeed, such a gradient would combine the very low coefficient of thermal expansion (CTE) of Invar 36 with the low cost and excellent chemical resistance of 316L stainless steel. A particularly relevant application for this type of gradient is the storage of hydrogen or liquefied natural gas, where tanks are subjected to severe thermal stresses due to cryogenic operating temperatures. In addition, these structures must withstand aggressive environments and hydrogen exposure, which can induce material embrittlement, while maintaining sufficient mechanical properties to ensure structural integrity during service. Designing an optimal gradient therefore requires a detailed understanding of how mechanical, thermal, and chemical properties evolve with chemical composition. This study provides a preliminary assessment of these evolutions. The results show that the addition of 15–25 wt.% Invar 36 to 316L leads to a reduction in microhardness and ultimate tensile strength (UTS), associated with the disappearance of ferritic and σ phases, while significantly enhancing ductility. At higher Invar 36 contents, microhardness increases and ductility decreases due to carbide formation. From a thermal standpoint, the CTE does not follow a linear trend: it remains high up to approximately 75 wt.% Invar 36 Nb, then decreases sharply as the ferromagnetic behavior characteristic of Invar becomes dominant. Corrosion resistance remains satisfactory for Invar 36 contents below 15 wt.%, whereas higher contents lead to reduced chemical performance due to chromium dilution. Overall, these findings establish clear criteria for selecting optimal compositions in the design of a 316L–Invar 36 compositional gradient. They provide an essential foundation for the development, via WAAM, of robust and high-performance functionally graded materials suitable for applications requiring high dimensional stability, good chemical resistance, and controlled costs.

Abstract: This study presents the characterization of 316L stainless steels fabricated by selective laser melting (SLM), focusing on the influence of printing parameters on microstructure and mechanical properties. The choice of process parameters is crucial for achieving desired material properties, as it directly affects the microstructure and mechanical behavior, which is important when optimizing for potential applications in several fields, such as aerospace and automotive. In this study, different scanning speeds were tested to identify optimal settings, followed by the evaluation of the effects of orientation relative to the build plate and hatching strategies to enhance performance. To assess the impact of these factors, tensile tests, microhardness measurements, and X-ray diffraction (XRD) analyses were conducted. Tensile tests revealed that higher laser scanning speed generally reduces ultimate tensile strength and elongation, likely due to an increase in porosity and a less homogeneous fusion of layers. The analysis of samples printed with different orientation relative to the build plate highlighted a strong mechanical anisotropy, with the samples printed vertically exhibiting lower tensile strength and ductility compared to horizontally printed samples. Microhardness testing further confirmed an anisotropy in material properties. XRD analysis reveals a preferential orientation of austenitic grains depending on building direction. This, in turn, influences the anisotropic behavior. These findings highlight the critical role of process parameters in tailoring the microstructure and mechanical performance of SLM-produced parts, thereby providing insights into the optimization of additive manufacturing for specific applications.

Abstract: This study uses numerical simulation to examine the influence of variations in laser power and transition zone length on the tensile behavior of bimetallic samples designed to be manufactured by selective laser melting (SLM). The materials studied are 316L stainless steel-copper, chosen for their complementary mechanical properties and functional relevance in high-stress applications. The transition between the two materials was modeled by modulating the laser power according to different profiles (linear, concave or convex) and over different lengths (d(x) = 0 mm, 10 mm, 20 mm) in order to evaluate their impact on the simulated mechanical performance. The numerical results show that a gradual transition in laser power, combined with an extended transition zone, significantly improves stress distribution and leads to better mechanical integrity. Simulations performed in ANSYS provide an in-depth analysis of stress fields and highlight the crucial role of manufacturing parameter management. This study thus highlights the importance of precise control of manufacturing parameters in the 3D printing of bimetallic components and demonstrates, through numerical modeling, that optimized transition management can improve the mechanical integrity of parts produced by SLM. Experimental validation of these results will be an essential prospect for future work.

Abstract: This study presents a comparative analysis of manufacturing techniques for 316L stainless steel, focusing on Direct Energy Deposition (DED) and traditional casting methods. The research aims to evaluate the differences in microstructure, mechanical properties, and overall performance of components produced by these two distinct processes. Through a series of experiments and material characterizations, including microscopic examinations and mechanical testing, we investigate how the manufacturing techniques influence the final properties of 316L stainless steel. Our findings reveal significant variations in grain structure, porosity, and tensile strength, highlighting the advantages and limitations of each method. This comparative study provides valuable insights for industries seeking to optimize their manufacturing processes for high-performance applications, ultimately contributing to the advancement of additive manufacturing technologies and traditional casting techniques.

Abstract: In the present study, titanium dioxide (TiO₂/Chitosan) nano-particles layer coatings were fabricated by electrophoretic deposition on 316 Austenitic Stainless steel substrate. Aims to enhance antibacterial properties by coating the surface with a bio ceramic (TiO₂) nano-powders. TiO₂, were made on 316 austenitic stainless steel substrate with an EPD (electrophoretic deposition) technique, charged particles suspended in ethanol at a concentration of 50 g/L, for each powder with ideal conditions of 20V and a deposition time of (2, 4 and 6 min). The surface tests of coated substrates, such as, micro-hardness, surface roughness and wettability antibacterial test were evaluated and compared to that of the uncoated substrates. The showed results the electrophoretic deposition is a favorable technique to make a bio coating on 316 Austenitic Stainless steel substrate with excellent properties and structure for applications biomedical. The results demonstrated that the coated sample under coating conditions (20V, 2min) which is close to the ratio found in living bone. the average micro-hardness of the TiO2 coated sample is 1483 HV compared with that of uncoated substrates is 460 HV. The results also of the wettability test showed that the contact angle of the deposited paint is 5.9 degrees, and this positive result is useful for biomedical applications and proved that the coating is hydrophilic.

Abstract: Nowadays, 316L stainless steel implant materials exhibit a promising position in the field of biomaterials application, especially in medical due to their higher strength compared to other ceramic base materials. Therefore, in this work, the production of 316L implant materials and examination of the mechanical characteristics were carried out. Powder Metallurgy process has been chosen to produce the implant materials due to its high advantages in demonstrating the high mechanical properties of the green sample. 316L stainless steel with zinc streate powder of three different compositions, i.e., the first of 99% 316L stainless steel and 1% zinc stearate, the second of 97% 316L stainless steel and 3% zinc streate, and the third of 95% 316L stainless steel and 5% zinc streate, were cold pressed individually at 600 MPa pressure using UTM and sintered the green samples at 1120 °C for 1 hour and 30 minutes. Sintering temperature and time were the same for all the specimens. We investigated the mechanical behaviour of 316L stainless steel implant materials of different compositions at the same temperature for the same duration of time. After that, the mechanical properties and densification of this material were investigated.

Abstract: Additively manufactured (AM) 316L stainless steel (SS) often contains cellular dislocation structure which is a distinct microstructural feature compared with those fabricated traditionally, like casting and forging. The role of this unique cellular dislocation structure on the mechanical properties of the AM 316L SS needs to be determined to guide its further performance improvement. In this study, the effect of cellular dislocation structure on the strength of AM 316L SS was investigated via micro-mechanical compression test. Single crystalline micro-pillars were firstly prepared from both the as-built and annealed AM 316L SS bulk specimens, with and without cellular dislocation structure relatively. The results show a significant increase of the yield strength of the micro-pillars with the cellular dislocation structure. The micro-pillars containing cellular dislocation structure with different sizes and morphologies have been studied to evaluate the effect of cellular dislocation structure on the strength of AM 316L SS.

Abstract: Selective Laser Melting SLM is one of the most popular three dimensional printing methods, which can be used for manufactured real elements (with high geometrical complexity) in many application, such as medicine, automotive or aerospace industries. The SLM final parts are characterized by high mechanical properties and satisfactory physicochemical properties. However, the properties of parts depend of process parameters optimization. In this paper, effects of processing parameters, such as laser power P, scanning speed SP, layer thickness t or point distance PD on defect formation and relative densities of manufactured elements are explored. For the purpose the stainless steel 316L and pure titanium Grade II are used. The process optimization were carried out according to the formula of energy density, which is delivered to the powder material. The stainless steel samples were divided into 12 groups, depends of the energy density. The titanium parts were printed at the same value of energy, and the process parameters are changed. The microscope observation and relative density measurements were carried out. Based on the obtained results, it can be confuted that the SLM parameters have a significant effect on the samples properties and the mechanism formed defect in both material are similar.

Abstract: 316L stainless steel is used in various industrial applications including chemical, biomedical and mechanical industries due to its good mechanical properties and corrosion resistance. Recycling of 316L stainless steel scrap without significantly reducing its value has received recently great attention because of the environmental regulations. In the current work, 316L stainless steel scrap was recycled via casting using Skull induction melting technique. The casted products subsequently subjected to laser surface melting process to improve its surface properties to be used for harsh environment. The results showed defect free surfaces with homogeneous microstructures. Nano size grains were also obtained due to rapid solidification process. Such nano size grains are preferred for extending the usage of the 316L stainless steel in new applications.Corresponding author: E-Mail: elgazzar.ha@gmail.com

Abstract: A novel biocompatible fluorine substituted hydroxyapatite (F-HAp) / poly (ε-caprolactone) (PCL) bilayer coating on 316L SS with superior adhesion strength and admirable corrosion protection properties. PCL slurry was coated on 316L SS as a first layer using dip coating method followed by F-HAp coating as the second layer using electrodeposition method. The structural and functional group analysis of bilayer coatings were characterized by different analytical technique. Also, the mechanical properties of the bilayer coating showed higher adhesion strength than HAp and F-HAp coatings on 316L SS. The potentiodynamic polarization and electrochemical impedance spectroscopy results indicated that the admirable corrosion protection nature. The in vitro bioactivity test for coated 316L SS substrate was carried out by soaking it in the SBF solution, the induced apatite formation confirming the improved bioactivity of the specimen. Further, dissolution of metal ions was considerably reduced which was confirmed by inductively coupled plasma-atomic emission spectroscopy (ICP-AES). The in vitro cell–material interaction of the bilayer coating was studied with human osteosarcoma MG63 cells for cell viability at 3, 7, 14 and 21 days of incubation and good biocompatibility was observed. The obtained results show that the F-HAp/PCL bilayer coating provides effective corrosion protection and enhanced bioactivity.