Autogenous Fiber Laser Welding of 316L Austenitic and 2304 Lean Duplex Stainless Steels
TL;DR: Non-destructive tests and metallographic examinations showed that the welded joints meet the acceptance criteria for B level in accordance with EN ISO 13919–1 standard, and the results of the destructive tests confirmed the high quality of the joints.
Abstract: This study presents results of experimental tests on quality of dissimilar welded joints between 316L austenitic and 2304 lean duplex stainless steels, welded without ceramic backing. Fiber laser welded butt joints at a thickness of 8 mm were subjected to non-destructive testing (visual and penetrant), destructive testing (static tensile test, bending test, and microhardness measurements) and structure observations (macro- and microscopic examinations, SEM, element distribution characteristics, and ferrite content measurements). Non-destructive tests and metallographic examinations showed that the welded joints meet the acceptance criteria for B level in accordance with EN ISO 13919–1 standard. Also the results of the destructive tests confirmed the high quality of the joints: specimens were fractured in base material with lower strength—316L austenitic stainless steel and a 180° bending angle was obtained confirming the high plasticity of the joints. Microscopic examination, SEM and EDS analysis showed the distribution of alloying elements in joints. The microhardness of the autogenous weld metal was higher by about 20 HV0.2 than that of the lean duplex steel. Ferrite content in the root was about 37% higher than in the face of the weld. The Schaeffler phase diagram was used to predict the phase composition of the welded joints and sufficient compliance with the magnetic method was found. The presented procedure can be used for welding of 316L–2304 stainless steels dissimilar welded joints of 8 mm thickness without ceramic backing.
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TL;DR: In this paper, the authors present an overview of the dissimilar welded joint's microstructure and mechanical behavior, and the effect of intermetallic phases such as sigma phase, FCC carbides like (M23C6, M6C, and M7C3), laves phase, R and χ-phase, Z-phase on the mechanical property of dissimilar welding joints of each material are reviewed in detail.
64 citations
TL;DR: A dissimilar autogenous laser welded joint of AISi 430F (X12CrMoS17) martensitic stainless steel and AISI 304 (X5CrNi18-10) austenitic stainlesssteel was manufactured and revealed a mixture of ferrite and carbides with many type II sulfide inclusions that showed that they were Cr-rich manganese sulfides.
Abstract: A dissimilar autogenous laser welded joint of AISI 430F (X12CrMoS17) martensitic stainless steel and AISI 304 (X5CrNi18-10) austenitic stainless steel was manufactured. The welded joint was examined by non-destructive visual testing and destructive testing by macro- and microscopic examination and hardness measurements. With reference to the ISO 13919-1 standard the welded joint was characterized by C level, due to the gas pores detected. Microscopic observations of AISI 430F steel revealed a mixture of ferrite and carbides with many type II sulfide inclusions. Detailed analysis showed that they were Cr-rich manganese sulfides. AISI 304 steel was characterized by the expected austenitic microstructure with banded δ-ferrite. Martensitic microstructure with fine, globular sulfide inclusions was observed in the weld metal. The hardness in the heat-affected zone was increased in the martensitic steel in relation to the base metal and decreased in the austenitic steel. The hardness range in the weld metal, caused by chemical inhomogeneity, was 184–416 HV0.3.
46 citations
Cites background from "Autogenous Fiber Laser Welding of 3..."
...However, these inconveniences and risks are taken due to the many benefits that arise from combining two very different materials, reducing both production and operating costs and the improving mechanical properties of the joints [16,17]....
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TL;DR: In this paper , a 316L stainless steel to Inconel 625 functionally graded material (FGM) was built using different deposition strategies (named as direct and smooth-type interfaces) by Twin-Wire and Arc Additive Manufacturing (T-WAAM).
Abstract: In this work, a 316L stainless steel to Inconel 625 functionally graded material (FGM) was built using different deposition strategies (named as direct and smooth-type interfaces) by Twin-Wire and Arc Additive Manufacturing (T-WAAM). This combination of materials is of interest in chemical plants, oil & gas, and nuclear applications, where high corrosion and wear resistance are essential requirements. Although these properties are superior in Inconel 625, replacing Inconel with stainless steel in strategic regions of structural components can reduce the overall costs and parts’ weight. Both direct and smooth transition interfaces were tested and characterized. Microscopic analysis revealed that each interface and the as-built samples had an austenitic matrix, and every sample was well bonded and free of defects. Different types of microstructures evolved at the interfaces due to distinct gradients in composition. Synchrotron X-ray diffraction measurements showed that the smooth-gradient produced secondary phases, such as δ-phase (Ni 3 Nb) and carbides, that were not present with the direct interface strategy. Overall, the properties were superior in the FGM with a direct interface, which experienced higher strengths and elongations upon failure. Moreover, neutron diffraction measurements revealed that lower residual stresses developed in the direct interface FGM than in the smooth gradient FGM.
44 citations
TL;DR: In this paper , a dissimilar laser beam welded joint of ferritic/martensitic P92 steel, and 304L austenitic stainless steel (ASS) has been examined in as-weld and postweld heat treatment (PWHT) at 760 °C for 120 min for microstructure feature and mechanical aspects.
29 citations
05 Jul 2021
TL;DR: In this article, a multiphysics numerical model was proposed to explore the factors affecting the production of parts in the selective laser melting (SLM) process and the mathematical relationships between them, using stainless steel 316L powder.
Abstract: The parameter sets used during the selective laser melting (SLM) process directly affect the final product through the resulting melt-pool temperature. Achieving the optimum set of parameters is usually done experimentally, which is a costly and time-consuming process. Additionally, controlling the deviation of the melt-pool temperature from the specified value during the process ensures that the final product has a homogeneous microstructure. This study proposes a multiphysics numerical model that explores the factors affecting the production of parts in the SLM process and the mathematical relationships between them, using stainless steel 316L powder. The effect of laser power and laser spot diameter on the temperature of the melt-pool at different scanning velocities were studied. Thus, mathematical expressions were obtained to relate process parameters to melt-pool temperature. The resulting mathematical relationships are the basic elements to design a controller to instantly control the melt-pool temperature during the process. In the study, test samples were produced using simulated parameters to validate the simulation approach. Samples produced using simulated parameter sets resulting in temperatures of 2000 K and above had acceptable microstructures. Evaporation defects caused by extreme temperatures, unmelted powder defects due to insufficient temperature, and homogenous microstructures for suitable parameter sets predicted by the simulations were obtained in the experimental results, and the model was validated.
28 citations
References
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TL;DR: In this article, the effect of welding processes and conditions on microstructure, mechanical properties and corrosion resistance of duplex stainless steels and its various combinations on the basis of structure-property co-relationship are systematically highlighted.
219 citations
"Autogenous Fiber Laser Welding of 3..." refers background in this paper
...Guidelines for welding duplex steels can be found in scientific reports [17,19], regulations and standards, e....
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TL;DR: In this paper, the microstructure and corrosion resistance of dissimilar weld-joints between stainless steel SAF 2205 and stainless steel AISI 316L were investigated, and different types of welding wires AWS ER 347, AWS ER 316L and AWS ER 309L were used to verify soundness of welded samples.
94 citations
"Autogenous Fiber Laser Welding of 3..." refers background in this paper
...However, among the various austenitic consumables, the most beneficial, both in terms of strength properties, as well as morphology and corrosion resistance, is the use of 309L [47,48] or super austenitic 904L filler metal [49]....
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30 Jan 2017
TL;DR: In this paper, the effects of input heat of different welding processes on the microstructure, corrosion, and mechanical characteristics of welded duplex stainless steel (DSS) are reviewed.
Abstract: The effects of input heat of different welding processes on the microstructure, corrosion, and mechanical characteristics of welded duplex stainless steel (DSS) are reviewed. Austenitic stainless steel (ASS) is welded using low-heat inputs. However, owing to differences in the physical metallurgy between ASS and DSS, low-heat inputs should be avoided for DSS. This review highlights the differences in solidification mode and transformation characteristics between ASS and DSS with regard to the heat input in welding processes. Specifically, many studies about the effects of heat energy input in welding process on the pitting corrosion, intergranular stress, stresscorrosion cracking, and mechanical properties of weldments of DSS are reviewed.
79 citations
TL;DR: In this paper, the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super- duplex (ER2594) and an austenite (ER309LMo) stainless steel filler metal.
Abstract: To study the effect of chemical composition on microstructural features and mechanical properties of dissimilar joints between super duplex and austenitic stainless steels, welding was attempted by gas tungsten arc welding process with a super duplex (ER2594) and an austenitic (ER309LMo) stainless steel filler metal. While the austenitic weld metal had vermicular delta ferrite within austenitic matrix, super duplex stainless steel was mainly comprised of allotriomorphic grain boundary and Widmanstatten side plate austenite morphologies in the ferrite matrix. Also the heat-affected zone of austenitic base metal comprised of large austenite grains with little amounts of ferrite, whereas a coarse-grained ferritic region was observed in the heat-affected zone of super duplex base metal. Although both welded joints showed acceptable mechanical properties, the hardness and impact strength of the weld metal produced using super duplex filler metal were found to be better than that obtained by austenitic filler metal.
75 citations
"Autogenous Fiber Laser Welding of 3..." refers methods in this paper
...recommend using duplex instead of austenitic consumable when using the TIG process [46]....
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TL;DR: In this article, the joining of dissimilar combinations of austenitic stainless steel, AISI 316L and super-duplex stainless steel (UNS S32750) by continuous current (CC) and pulsed current (PC) gas tungsten arc welding (GTAW) using ER2553 and ERNiCrMo-3 fillers was examined using both optical and scanning electron microscopy (SEM) techniques.
74 citations