Showing 9 results for 316l
R. Ghasemi, E. Heshmat Dehkordi, M. Shamanian,
Volume 2, Issue 1 (8-2016)
Abstract
In this study, microstructural features and mechanical properties of Incoloy 825-316L stainless steel dissimilar joints have been investigated. For this purpose, pulsed gas tungsten arc welding method was employed and 316L, Inconel 82 and Inconel 625 alloys were used as filler metal. First, specimens were cut. Pulsed gas tungsten arc welding was performed using peak and base currents of 220 A and 110 A, respectively. Microstructure of welded joints was studied using metallographic observations and energy dispersive spectroscopy (EDS) analysis. In order to evaluate the mechanical properties, tensile and microhardness measurements were done on the joints. In all specimens, dendritic and equiaxed and/or cellular growth of austenite phase was observed. Incoloy 625 weld metal had the finest dendritic structure. Tensile test results revealed the ductile fracture with a high percent of elongation for all specimens. The highest tensile strength and percent of elongation of 610 MPa and 48% were obtained for specimen welded using Inconel 625 filler metal. Inconel 625 and 316 stainless steel weld metals showed the highest and lowest microhardness with values of 232 HV and 224 HV, respectively.
Morteza Abbasi, Hamidreza Najafi, Alireza Khodabandeh,
Volume 4, Issue 1 (8-2018)
Abstract
Dissimilar welding of AISI 304L austenitic stainless steel to AISI 409 ferritic stainless steel with GMAW process usingtwo Ar-O2 and Ar-CO2 shielding gas mixtures was studied. ER316LSi and ER309LMo filler metals were chosen by considering 5 and 15% delta ferrite according to the Schaeffler equations and diagram. Based on the observations, both filler metals accompanied by Ar-2%O2 shielding gas resulted in acceptable weldments. Yield strength and UTS of tensile samples were 288 and 424 MPa, respectively. All tensile samples fractured in the ferritic base metal. Microhardness test results demonstrated that the maximum hardness of 190-200 HV was obtained from ER316LSi weld metal. The minimum hardness of 145 HV was found in the HAZ of 409 side mainly due to the grain coarsening. Microstructural examinations revealed needle-like precipitates formed perpendicular to each other in the HAZ of 409 stainless steel. It seemed that the pre-existing TiC precipitates evolved into the needle shape precipitates as a result of rapid heating and cooling rates during the welding process.
N. Rahimi, T. Saed,
Volume 5, Issue 2 (1-2020)
Abstract
In this study the effect of activating fluxes on the penetration depth, microstructure and microhardness of AISI316L austenitic stainless steel were evaluated by three TIG process variations (TIG, A-TIG and FB-TIG) and the results were compared together.. After selecting the optimal flux in the second stage, the effect of that on the penetration depth, microstructure and weld microhardness of welded 316L austenitic stainless steel by A–TIG and FB-TIG methods, were evaluated and the results were compared by the sample which was welded by TIG process. At this stage, it was found that the depth and width to depth ratio in FB-TIG method is slightly greater than the other two methods. Also in FB-TIG method, eqiaxed dendritic zone in the center line of weld is slightly greater than in A-TIG method. Study of microhardness of weld in three methods shows that in A-TIG and FB-TIG methods hardness of center line is more than TIG method.
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Volume 6, Issue 1 (8-2020)
Abstract
In this research, effect of time and temperature of TLP process on the microstructure, mechanical properties and corrosion resistance of CP-Ti to 316L stainless steel joint evaluated. For this purpose pure copper foil with 100 µm thickness was used as interlayer and joining process carried out at 950˚C, 1000˚C and 1050˚C and for 90, 120 and 150 minutes. After the joining process, shear and micro-hardness test and corrosion resistance were applied in the samples. The test results revealed that the shear strength of the sample 1000˚C is better than two other soaking temperatures. The main reason was the formation of less intermetallic compounds at the interface, as well as the presence of less athermally solidification zone area. Microstructural examinations for the sample after TLP at 950˚C revealed no iron and titanium bearing intermetallic compounds in the interface while for two other samples, there exist considerable amount of intermetallics in the microstructure. Corrosion test results showed that the resistance against corrosion depends on the intermetallic compounds formed in the interface. Intermetallic phases includes FeTi, TiCu, Ti2Cu, and TiCu2. The sample prepared at 1000˚C for 120 minutes had less intermetallic compounds and as a result, had the best corrosion resistance. Fe and Ti containing intermetallics had good corrosion resistance in simulated body fluid, as comparison with Ti and Cu containing compounds.
M. J. Bagban, M. Mosallaee Pour, H. Hajisafari, A. Babnejad, A. Saboori,
Volume 8, Issue 1 (8-2022)
Abstract
In the present study, the microstructure and mechanical properties of the dissimilar joint of Inconel 625 (IN-625) superalloy to austenitic stainless steel AISI316L (SS-316L) via AWS-BNi3 interface layer and transient liquid phase (TLP) bonding process were evaluated and necessary conditions for creating an efficient joint were determined. TLP bonding was performed in temperature and time range of 1050-1150ºC and 5-20min, respectively, under the protection of argon shielding gas with a purity of 99.9995%. Microstructural (OM and SEM) and phase (XRD) studies revealed that bonding at 1150 ° C for 20 min results in completion of isothermal solidification and develops a uniform gamma (γ) phase at the bonding zone. Cooling the samples before completion of isothermal solidification results in the formation of chromium and molybdenum-rich eutectic compounds at the bonding centerline. The continuous morphology of the eutectic compounds caused a sharp drop in the shear strength of the specimens (~50% reduction of shear strength). The inter-diffusion of alloying elements between the bonding area and the surrounding base metal results in the formation of chromium carbide in the IN-625 and chromium- boron compounds in the SS-316L, which increased the microhardness of these areas compared to the base metals and the bonding zone.
M. Naseri Alenjagh, T. Saeid,
Volume 9, Issue 1 (5-2023)
Abstract
The purpose of this research is to investigate the change of rotational speed and traverse speed on the microstructure and mechanical properties of the joint in friction stir welding of aluminum 1050 and 316L stainless steel. For this purpose, the microstructure, thickness of intermetallic compounds, hardness and tensile test on the joint were investigated. The proper selection of welding parameters leads to the creation of a joint with suitable metallurgical and mechanical properties. In this research, two rotational speeds of 560 and 900 rpm and four traverse speeds of 60, 80, 100 and 125 mm/min were performed. The microstructure consisted of four areas of the base metal, heat affected zone, thermo-mechanical affected zone and stir zone. In all the samples, the stir zone (SZ) contained a recrystallization microstructure with fine equiaxed grains. According to the Energy dispersive X-ray Spectroscopy results, an IMC layer formed in the joint interface. The hardness of the stir zone in all samples was higher than the aluminum base metal due to the formation of recrystallization fine equiaxed grains and the presence of steel particles. The best sample in terms of mechanical properties, mocrostructure and joint quality was obtained in the conditions of rotation speed of 900 rpm and advance speed of 125 mm/min. The strength was equal to 84 MPa with 77% efficiency.
Behnam Heidari-Dehkordi, Mahdi Rafiei, Mahdi Omidi, Mohsen Abbasi-Baharanchi,
Volume 9, Issue 2 (8-2024)
Abstract
In this study, 316L stainless steel and WC-10Co cermet were bonded by transient liquid phase process with BNi-2 interlayers with different thicknesses of 25 and 50 μm. The bonding process was conducted at 1050 °C for 1, 15, and 30 min. After bonding, the microstructure of the joints was examined using optical microscopy and scanning electron microscopy equipped with energy-dispersive X-ray spectroscopy. Microhardness and tensile-shear tests were also performed to study the mechanical properties of the bonded samples. Microstructural analyses revealed that the formation mechanism of the solidified region in all samples was isothermal solidification, resulting in an isothermal solidification zone upon bonding. Additionally, the only phase present in the isothermal solidification zone was a nickel-based solid solution. In the diffusion-affected zone of the steel base material, complex borides formed regardless of the interlayer thickness. In the diffusion-affected zone of the WC-Co material, a brittle eta phase formed. Microhardness tests indicated that the maximum hardness in all samples was approximately 1100 Vickers, which was attributed to the presence of hard WC particles in the WC-Co base material. Furthermore, the highest tensile-shear strength, approximately 240 MPa, was observed in the bonded sample for 15 min with 50 μm thickness interlayer.
Hossein Abedi Chermahini, Mohammad Mahdi Piran, Ali Akbar Esmaeili Chamgordani, Masoud Atapour,
Volume 9, Issue 2 (8-2024)
Abstract
In this research, the mechanical properties and microstructure of L316 grade stainless steel sheets welded using the resistance spot welding method with a copper interlayer were investigated. In this regard, two types Connection were considered: one without the interlayer and the other with the copper interlayer, connected at different currents. To select the optimal current for both types of connections, tensile tests were initially conducted. Following that, microstructural examinations, microhardness tests, elemental evaluations, and failure mode analyses were performed on the optimized samples. according to the results obtained, increasing the electric current raised the input heat in the weld pool to an appropriate level, improving the microstructural and mechanical properties of the weld region. Additionally, due to the optimal electric current in both samples "with and without" the interlayer, both samples experienced interfacial failure, indicating high strength at their joint and weld points. Changes in chemical composition across different weld areas were minimal, and element distribution was reported to be uniform throughout all regions. The highest hardness was observed from the base metal towards the center of the weld in the order of weld area > base metal > heat-affected zone, which corresponded with results from microstructural examinations.
M. N. Sadraee Far, F. Kolahan,
Volume 9, Issue 2 (1-2024)
Abstract
In this study, we employed the active TIG method with ultrasonic vibration (UV) for welding 316L steel. Throughout the active tungsten inert gas (A-TIG) welding process, a high-frequency ultrasonic generator produced high-intensity acoustic waves at an optimal frequency of 20.3 kHz and a vibration amplitude of 8 micrometers. These waves were directed into the molten weld pool, covered by SiO2 nanoparticles serving as an activating flux. The effect of UV and nanoparticles on weld geometry and weld microstructure was analyzed and compared with conventional TIG welding proces. The results indicated that the use of nanopowder not only increased weld penetration by approximately 17.5% but also reduced the Weld Bead Width (WBW) by 28% compared to Conventional TIG. These values increased by 25% and decreased by 35%, respectively, in the presence of ultrasonic waves. Additionally, the introduction of nanomaterials into the molten pool led to finer grains. The ultrasonic waves played a crucial role in ensuring the uniform distribution of these nanomaterials in the melt, ultimately resulting in an enhanced microstructure of the weld.
