Effect of weld metal chemistry and heat input on the structure and properties of duplex stainless steel welds
15 Oct 2003-Materials Science and Engineering A-structural Materials Properties Microstructure and Processing (Elsevier)-Vol. 358, Iss: 1, pp 9-16
TL;DR: In this article, a low heat input process viz., EBW and another commonly employed process, gas tungsten-arc welding have been employed for welding of duplex stainless steels with and without nickel enhancement.
Abstract: The excellent combination of strength and corrosion resistance in duplex stainless steels (DSS) is due to their strict composition control and microstructural balance. The ferrite–austenite ratio is often upset in DSS weld metals owing to the rapid cooling rates associated with welding. To achieve the desired ferrite–austenite balance and hence properties, either the weld metal composition and/or the heat input is controlled. In the current work, a low heat input process viz., EBW and another commonly employed process, gas tungsten-arc welding have been employed for welding of DSS with and without nickel enhancement. Results show that (i) chemical composition has got a greater influence on the ferrite–austenite ratio than the cooling rate, (ii) and even EBW which is considered an immature process in welding of DSS, can be employed provided means of filler addition could be devised.
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TL;DR: In this article, the microstructure and mechanical properties of friction stir welded super duplex stainless steels were investigated by using optical microscope and scanning electron microscope, in order to evaluate the mechanical properties, microhardness and tensile test are utilized.
Abstract: The aim of this study is to investigate the microstructure and mechanical properties of friction stir welded super duplex stainless steels. In this regard, UNS S32750 steel is joined by friction stir welding (FSW) method. The tool used in this research is made of WC with 16-mm shoulder diameter and 5-mm pin diameter. Microstructural investigations are carried out by optical microscope and scanning electron microscope. In addition, in order to evaluate the mechanical properties, microhardness and tensile test are utilized. The results show that grain refinement occurs in the stir zone (SZ) during the FSW process. Image analysis reveals that the volume fraction of ferrite in the SZ was about 60%. Microhardness test shows that the average hardness value of base metal is 285 Vickers, however, in the stir zone, the hardness value is increased up to 360 Vickers.
3 citations
01 Jan 2019
TL;DR: Alagarsamy et al. as discussed by the authors optimized the gas metal arc welding parameters on the impact strength, hardness and flexural strength of dissimilar weld joints of SS316L and AISI D2 steels by using Taguchi based grey relational method.
Abstract: The current research work is to optimize the gas metal arc welding parameters on the impact strength, hardness and flexural strength of dissimilar weld joints of SS316L and AISI D2 steels by using Taguchi based grey relational method. The experiments were planned as per Taguchi L8 orthogonal array by considering four input parameters like current (amps), voltage (volt), speed (cm/min) and root gap (mm). The experimental results shows that, the maximum impact strength of 4.36 J/mm 2 , maximum hardness of 49.5 HRC and maximum flexural strength of 583.3 MPa was obtained for the weld joints fabricated under the optimum welding conditions of current 80 amps, voltage 15 volt, speed 45 cm/min and root gap 2.0 mm. Analysis of variance was used to determine the significant contribution of each welding parameter on the output characteristics. The percentage contribution graph shows that, root gap was the most significant parameter on multiple output responses that contributes P-54.64% followed by welding speed of P20.26% and voltage of P11.94%. Original Research Article Alagarsamy and Kumar; JMSRR, 4(3): 1-10, 2019; Article no.JMSRR.53853 2
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Cites background from "Effect of weld metal chemistry and ..."
...These features are hardly influenced by various input parameters of the welding such as current, voltage, welding speed and gas flow rate etc [11-14]....
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TL;DR: In this article, the surface electrochemical corrosion activity of the economic lean duplex stainless steel LDX2101 was investigated in situ in chloride solution with a combination of long working distance microscope (LWDM) and electrochemical techniques.
Abstract: The surface electrochemical corrosion activity of the economic lean duplex stainless steel LDX2101 was investigated in situ in chloride solution with a combination of long working distance microscope (LWDM) and electrochemical techniques. In addition, the site and chemical composition of the electrochemical active points on the specimen surface were also determined with integrated scanning electron microscope/energy dispersive X-ray spectroscope (SEM/EDS) system. The results demonstrated that: (i) The reaction of alpha -> Cr2N + gamma 2 precedes that of alpha -> sigma + gamma 2 when LDX2101 was aged at 700 degrees C. (ii) The initiation sites of electrochemical active points could be determined by LWDM in combination with potentiostatic pulse technique (PPT). (iii) The sites of electrochemical active points were found to change from inclusions (MnS/Al2O3) to secondary austenite phase (gamma 2), with the increase of aging time at 700 degrees C.
3 citations
Dissertation•
03 Jul 2012
TL;DR: In this article, a 3D model for the thermo-mechanical analysis of thin stainless steel butt-joint plates has been developed, which incorporates the effects of thermal energy redistribution through weld pool dynamics into the structural behavior calculations.
Abstract: Welding is used extensively in aerospace, automotive, chemical, manufacturing, and powergeneration industries. Thermally-induced residual stresses due to welding can significantly impair the performance and reliability of welded structures. Numerical simulation of weld pool dynamics is important as experimental measurements of velocities and temperature profiles are difficult due to the small size of the weld pool and the presence of the arc. It is necessary to have an accurate spatial and temporal thermal distribution in the welded structure before stress analysis is performed. Existing research on weld pool dynamics simulation has ignored the effect of fluid flow in the weld pool on the temperature field of the welded joint. Previous research has established that the weld pool depth/width (D/W) ratio and Heat Affected Zone (HAZ) are significantly altered by the weld pool dynamics. Hence, for a more accurate estimation of the thermally-induced stresses it is desired to incorporate the weld pool dynamics into the analysis. Moreover, the effects of microstructure evolution in the HAZ on the mechanical behavior of the structure need to be included in the analysis for better mechanical response prediction. In this study, a 3D-model for the thermo-mechanical analysis of Gas Tungsten Arc (GTA) welding of thin stainless steel butt-joint plates has been developed. The model incorporates the effects of thermal energy redistribution through weld pool dynamics into the structural behavior calculations. Through material modeling the effects of microstructure change/phase transformation are indirectly included in the model. The developed weld pool dynamics model includes the effects of current, arc length, and electrode angle on the heat flux and current density distributions and includes all the major weld pool driving forces are included. The weld D/W predictions are validated with experimental results. They agree well. The effects of welding parameters on the weld D/W ratio are documented. The workpiece deformation and stress distributions are also highlighted. The transverse and longitudinal residual stress distribution plots across the weld bead are provided. The mathematical framework developed here serves as a robust tool for better prediction of weld D/W ratio and thermally-induced stress evolution/distribution in a welded structure by coupling the different fields in a welding process.
3 citations
Cites background from "Effect of weld metal chemistry and ..."
...[112] conducted research on the effect of weld chemistry and heat input on the structure and properties of duplex stainless steel welds using autogenous-TIG and electron beam welding....
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References
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Book•
01 Jan 1997
TL;DR: In this paper, the authors present a non-destructive testing of welds for service experience, based on the application of service experience in metallurgy and metallurgical applications.
Abstract: Developments, grades and specifications Alloy design Microstructure Forming and machining Physical and mechanical properties Corrosion Stress corrosion cracking Welding metallurgy Welding processes Weld properties Non-destructive testing of welds Applications Service experience.
449 citations