Properties Of Dissimilar Welded Joints Research Articles

Comparative Analysis of Microstructure Evolution and Mechanical Properties of Dissimilar Welded Joints of AA7075/AA6061 via Friction Stir Welding, Tungsten Inert Gas Welding, and Tungsten Inert Gas + Friction Stir Processing

Comparative Analysis of Microstructure Evolution and Mechanical Properties of Dissimilar Welded Joints of AA7075/AA6061 via Friction Stir Welding, Tungsten Inert Gas Welding, and Tungsten Inert Gas + Friction Stir Processing

Effect of Heat Input on Microstructure and Properties of Laser-Welded 316L/In601 Dissimilar Overlap Joints in High-Temperature Thermocouple.

Heat input, a crucial factor in the optimization of high-temperature thermocouple laser welding, has a significant impact on the appearance and mechanical properties of dissimilar welded joints involving stainless-steel- and nickel-based alloys. This study focuses on laser overlay welding of austenitic stainless steels and nickel-based alloys. The findings indicate that an increase in heat input has a more pronounced effect on the penetration depth and dilution rate. Under high heat input, the weld has cracks, spatter, and other defects. Additionally, considerable amounts of chromium (Cr) and nickel (Ni) elements are observed outside the grain near the crack, and their presence increases with higher heat input levels. Phase analysis reveals the presence of numerous Cr2Fe14C and Fe3Ni2 phases within the weld. The heat input increases to the range of 30-35 J/mm, and the weld changes from shear fracture to tensile fracture. In the center of the molten pool, the Vickers hardness is greater than that of the base metal, while in the fusion zone, the Vickers hardness is lower than that of the base metal. The overall hardness is in a downward trend with the increase of heat input, and the minimum hardness is only 159 HV0.3 at 40 J/mm. The heat input falls within the range of 28-30 J/mm, and the temperature shock resistance is at its peak.

Investigation of distinct welding parameters on mechanical and corrosion properties of dissimilar welded joints between stainless steel and low carbon steel.

The tensile strength and corrosion behavior of dissimilar welded joints are currently a subject of concern. In this work, gas metal arc welding (GMAW) and distinct welding parameters (welding current, arc voltage, and welding speed) were used to join 304 stainless steel (SUS304) and SS400 low carbon steel, and the ultimate tensile strength (UTS) of the dissimilar welded joints was investigated. A corrosion test was conducted by immersion in 3.5 wt.% sodium chloride (NaCl) solution for 7, 14, and 21 days. Based on tensile strength and Tafel testing, the welding parameters "Item 4" (welding current: 170 A, arc voltage: 20 V, welding speed: 40 cm/min) yielded good mechanical strength and low corrosion characteristics. The microstructure characterization showed that the area around the welded joints and SUS304 had more granular corrosion and corrosion tubercles with increasing immersion time. The chromium content gradually decreased. When exposed to the chloride environment, these welded joints easily underwent corrosion due to the loss of passivity. However, high-velocity oxygen-fuel (HVOF) spray used on the welded joints reduced the corrosion current density. Compared with the non-thermal spray sample (corrosion current density:7.49e - 05 A/cm2) while the corrosion current density (7.89e - 10 A/cm2) is five orders of magnitude lower. This spray effectively slowed down the corrosion rate of the welded joints and gave the structural objects good protection in the sodium chloride solution.

Study on the Microstructure Characteristics and Mechanical Properties of Dissimilar Weld Joints of Coiled Tubing

This work aims to investigate the microstructure and the mechanical behavior of dissimilar API X80-AISI 4130 steel welded joints of coiled tubing. The microstructure at the weld interface of the AISI 4130 steel side results in a relatively lower toughness. The HAZ of AISI 4130 steel has an obvious coarsening phenomenon. The tensile tests show that the deformation process of the dissimilar weld joint is mainly controlled by the two base materials: AISI 4130 steel at the beginning of the deformation and API X80 steel at its end. Charpy impact toughness tests conducted on dissimilar welded specimens led us to conclude that the higher Ni content accounts for a more gradual decline in impact tough-ness for AISI 4130 steel.

Effect of faying surfaces and characterization of aluminium AA6063–steel AISI304L dissimilar joints fabricated by friction welding with hemispherical bowl and threaded faying surfaces

This work describes the effect of newly introduced faying surfaces on the microstructure and the mechanical properties of dissimilar weld joints of AA6063 and AISI304L alloys that are fabricated through the rotary friction welding process (RFW). The experiments were done as six different experimental methods (‘A’ to ‘F’) at 1300 rpm rotation, 18 MPa friction pressure (FP), 24 MPa upset pressure (UP) and 5 s friction time (FT) with the faying surfaces of hemispherical bowl and thread of 1 mm pitch on the weld specimens. The fabricated joints and the weld zones were characterized by macro and microstudy, energy dispersive X-ray spectroscopy (EDS) spectrums, tensile properties, Vickers microhardness, impact toughness and fractography. The results showed that these faying surface modifications strengthen the bonding between the weld specimens and influences the performance of the joints. The hemispherical bowl showed better results than the threaded surfaces. Axial shortenings were within the acceptable limit in the range of 20–27 mm. Macro and microstructural studies showed the defect-free weld joints and the strong bonding between AA6063 and AISI304L alloys. The hemispherical faying surface on AISI304L alloy formed a U-shaped weld interface (WI) in the dissimilar joints. EDS proved the formation of the Fe–Al intermetallic and the element ‘O’ at weld zone. The joint efficiency for all the methods was around ≥100%. Maximum tensile strength was recorded as 238 MPa for method F. The threaded surface showed good hardness property nearby WI, and method A yielded maximum impact toughness for the joint.

Investigation on microstructure and properties of dissimilar joint between TRIP800 and QP980 fabricated by laser welding

Dissimilar weld joints of QP980 and TRIP800 were fabricated by a fibre laser. The microstructure and mechanical properties of dissimilar weld joints were studied. The tensile properties of weld joints were not influenced by the narrow softening zone with a less reduction in hardness of ∼25 HV from the QP980, which contributed to fracture in TRIP800. The DIC images showed that the location of maximum strain was changed from the QP980 side to TRIP800 side during the tensile test of QP980 (1.2 mm)–TRIP800 (1.4 mm) joints. The dissimilar weld joints were characterised by the limited dome height test (LDH). The LDH values were varied with the punch pole location, as a result of the softening zone and non-uniform microstructure on the heat-affected zone of joints.

Numerical Simulation of the Effect of Shoulder Rotation on the Tensile Strength of FSW Dissimilar Joints of Aluminum Alloy

Dissimilar weld metal joints such as aluminum alloys 5083 and 6061-T6 are mostly found in the application of aircraft, railroad structures, ships, bridges, and oil platforms and building structures. However, dissimilar welding metal is relatively more difficult due to metallurgical differences and the thermophysical properties of two different materials. The purpose of this study is to study the effect of shoulder rotation variations on the Friction Stir Welding (FSW) process through numerical simulations on the mechanical properties of dissimilar weld joints between two series of aluminum alloys, and there are 5083 and 6061-T6. The FSW welding simulation process is conducted by butt joints type on 300 x 100 x 3 mm of both aluminum plates with weld distance is 300 mm. Shoulder rotation variations are carried out for this process include 1,200, 1,400 and 1,600 rpm. Results show maximum temperature distributions are 467 oC for 1,200 rpm, 499 °C for 1,400 rpm and 527 °C for 1,600 rpm, respectively. Maximum temperatures appear close to the liquid temperature of Al-6061-T6 and Al 5083 base metals, which is about 600 °C. Physical and mechanical analysis at 1,200 rpm (the rotation parameter) can be seen as the coarse weld beads on the microstructure, and the weld joint is still weak. The physical properties observed that coarse weld beads on microstructures, the tensile strength obtained 138 MPa at 1,200 rpm (the rotation parameter). The maximum hardness test occurred 47.98 (Kg/mm2 in averages) at 1,400 rpm. The tensile strength of the dissimilar FSW process is 151 MPa occurred at 1,600 rpm of shoulder rotation speed. While the fracture position occurs in the nugget weld area for all parameters and corresponds with the result of hardness tests, it shows that low hardness value for the whole weld area for all parameters.

Study of structural non-homogeneity impact on mechanical properties of dissimilar weld joints of carbon steel 20 and corrosion-resistant austenitic 12Kh18N10T steel

The paper is devoted to identifying features of structural non-homogeneities formation in dissimilar welded joints of carbon steel 20 to corrosion-resistant austenitic 12Kh18N10T steel, obtained by tungsten inert gas welding (TIG), as well as studying of their influence on the mechanical characteristics of welded joints under static and cyclic loading. Differences in the formation of a diffusion carbide interlayer in weld metal alloyed with nickel and manganese are established. When austenite is alloyed with nickel, bulk carbon diffusion occurs, while in manganese austenite boundary diffusion becomes the main mechanism for carbon diffusion, which occurs mainly along grain and sub-grain boundaries of austenite. As a result of mechanical tests, it was established that under static tension welded joint works under conditions of strengthening by a soft (ferritic) layer due to the restraint of transverse deformations by more solid (carbide) layer. The limits of soft interlayer dimensions, under which the softening of welded joint does not occur, are established that will allow to proceed to the extreme temperature-time parameters of heat treatment and operation of welded joint.

Investigation of microstructural behavior and mechanical properties of dissimilar weld joints of austenitic-ferritic stainless steel

Joining of AISI 316L (austenitic stainless steel) and AISI 409M (ferritic stainless steel) was carried out using MIG welding at different root gaps and notch angles. The mechanical properties of similar and dissimilar welded joint were examined using tensile test. The results show that the interfacial microstructures and mechanical properties are strongly affected by joining configuration. When compared in similar material welded joints, it was observed that the yield strength and tensile strength of 2 mm root gap with 60° notch angle was highest. Also, the welded butt joint with 2 mm root gap and 60° notch angle showed highest strength among all dissimilar welded joints.

Effect of heat input on microstructure and properties of dissimilar laser welded joints between TWIP and TRIP steels

In this present, the experimental steels were produced by different rolling and heat treatment processes. After that, dissimilar laser tailor welding was carried out with different heat inputs (40, 60 and 100 J/mm2) using IPG YLR 6000 fiber laser with Ar gas shielding. Hitachi SU5000 scanning electron microscope (SEM) and Zeiss Axio Vert.Al optical microscope were used to observe the microstructure of the welded joints after being polished and etched with 4% nital. HV-1000 microhardness tester was used to measure the microhardness of welded joints. Tensile test was carried out using DNS-100 universal material testing equipment, and Erichsen test was conducted using CTM604 Erichsen test machine. Five groups of repeated experiments were selected for the performance test. Tensile fracture surface morphology of welded joint was observed by SEM. The effect of heat input on microstructure and properties of dissimilar welded joints between high manganese TWIP steels and low manganese TRIP steels was studied. The results showed that weld width and penetration were increased and complete penetration was obtained when the heat input increased to 60 J/mm2. With heat input increased, the microstructure of welded seam was more inhomogeneous. The distribution of Mn content in welded seam was inhomogeneous such that columnar/equiaxed austenite was formed in rich Mn zone and lath martensite was formed in barren Mn zone. Heat input had no influence on the microstructure and hardness on the HAZ. The mechanical properties of welded joints of 60 J/mm2 were superior and its strength-ductility balance was greater than TRIP BM (23 GPa%) and was 82% of TWIP BM (36 GPa%). The formability of 60 and 100 J/mm2 was similar.

Investigation on microstructure and tensile properties of dissimilar weld joints between AISI 316l and duplex 2205 stainless steel

The present study investigates the dissimilar weld joints between AISI 316L and Duplex 2205 stainless steel. The joints were fabricated with the Pulsed current gas tungsten arc welding with ER316L and ER309L filler wire. The weld joints were subjected to metallurgical and mechanical characterization. The macro examination and optical microstructure examination were carried out to see the defect in the weld joints and structural changes in the fusion zone. The results show that the defect free welding was achieved in the both the filler wire. The optical microstructure shows the ferritic structure in both filler wire. The strength of the weld joints was tested with the tensile test. The results indicate the fracture occurred in the base metal in both cases.

Mechanical properties of dissimilar welded joints of duplex 2205 and austenitic 316L steels

The presented work is the result of the author’s investigations connected with the examination of the usefulness of welding methods of dissimilar welded joints for their use in industrial practice (grade 2205- X2CrNiMoCuN22-5-3 steel with the number 1.4462 and typical, low-carbon austenitic steel of grade 316L - X2CrNiMo17-12-2 steel with the number 1.4404). In order to assess the characteristics of these joints the mechanical properties tests have been conducted. Mechanical properties tests included static tensile testing, static bending testing, impact tests and hardness measurements. Static testing did not produce results indicating the differentiation of mechanical properties. Impact tests have confirmed the negative correlation between the amount of heat introduced into the weld (including linear welding energy) and the impact strength of the welded joint. Hardness tests also confirmed the relationship between the heat input and the grain size of the main phases. The results of the mechanical properties shown that the lower the linear energy, the finer morphology of the manufactured welds.

Post-weld Heat Treatment and Groove Angles Affect the Mechanical Properties of T92/Super 304H Dissimilar Steel Weld Joints

AbstractThe microstructures and mechanical properties of dissimilar weld joints between T92 and Super 304H steels were investigated. Dissimilar weld joints with four groove angles were constructed using gas tungsten arc welding. The results showed that post-weld heat treatment improved the mechanical properties of the dissimilar weld joints. The optimal groove angle for T92/Super 304H dissimilar weld joints was found to be 20°, considering mechanical properties. Furthermore, the transformation from equiaxed dendrites to columnar dendrites was observed in the weld metal. Epitaxial growth and delta ferrites were found around the fusion line between the Super 304H and the weld metal.

Study on microstructure and properties of dissimilar welded joints of steel and aluminum by CMT welding process

This paper summarizes the characteristics of CMT welding technology, introduces the main application of CMT welding and analyses the influence of welding parameters on the microstructure and properties of welded joints of steel and aluminum. In the dissimilar welding of steel and aluminum by CMT, the suitable welding speed, wire feeding speed and preset clearance should be selected to obtain the welded joints with good microstructure and performance.

Comparative study of autogenous tungsten inert gas welding and tungsten arc welding with filler wire for dissimilar P91 and P92 steel weld joint

Creep strength enhanced ferritic/martensitic 9Cr-1Mo-V-Nb (P91) steel is also designated as ASTM A335 used for out-of-core and in-core (piping, cladding, ducts, wrappers, and pressure vessel) of Gen IV reactors. In present investigation, the dissimilar weld joint of P91 and P92 steel were made using the autogenous tungsten inert gas (TIG) welding with single pass, double side pass and multi-pass gas tungsten arc (GTA) welding with filler wire. Microstructure evolution in sub-zones and mechanical properties of dissimilar welded joints were studied in as-welded and post weld heat treatment (PWHT) condition. Formation of δ-ferrite patches in weld fusion zone and heat affected zones (HAZs) and their influence on the mechanical behaviour of the welded joints were also studied. Presence of higher content of ferrite stabilizer in P92 steel have resulted the formation of δ-ferrite patches in weld fusion zone as well as HAZs. The δ-ferrite was observed in autogenous TIG welds joints. The δ-ferrite patches were formed in as-welded condition and remained in the microstructure after the PWHT. The δ-ferrite patches leads to reduction in Charpy toughness of autogenous TIG welds joint and also lower down the average hardness of weld fusion zone. Peak hardness and poor impact toughness were observed for autogenous TIG welds joint as compared to GTA welds. For microstructure characterization, field-emission scanning electron microscope (FESEM) with energy dispersive spectroscopy (EDS) and optical microscope were utilized.

Hardness and tensile properties of dissimilar welds joints between SAF 2205 and AISI 316L

The mechanical properties of dissimilar weld joints between SAF 2205 and AISI 316L were investigated. Welding was accomplished by different types of welding wires: AWS ER 347, AWS ER 316L and AWS ER 309L. Microhardness and tensile tests were accomplished to evaluate hardness of the weld metal toward both sides of the base metals and to determine the strength of the weld joints. The weld metals of all samples exhibited higher hardness values than AISI 316L and lower values than SAF 2205 base metal. Welding wire 309L exhibited higher mechanical properties, while welding wire 347 showed weak mechanical properties. According to results, welding wire 309L was suitable for welding duplex stainless steel to austenitic stainless steel by gas tungsten arc welding process.

An evaluation of creep rupture strength of ferritic/austenitic dissimilar weld interfaces using cohesive zone modelling

Dissimilar metal welds between ferritic and austenitic alloys are used extensively in power generation plants. Failure of such welds can occur in the base metal, the heat-affected zone (HAZ), or the interface between the two materials, depending on the operating stress and temperature. Evaluation of the creep rupture properties of dissimilar weld joints of 2.25Cr-1Mo (P22) and 9Cr-1MoVNb (P91) ferritic steels with INCONEL 82 filler metal are described, with the primary focus on failure at the interface. The interface is modelled as a cohesive, or interface, zone within a finite element (FE) analysis. A Kachanov-type damage accumulation law is implemented to describe the response within the interface element, with the material parameters calibrated against available experimental data. The relationship between the damage mechanics model and the major microstructural features that are responsible for failure, is discussed.

Strain-controlled fatigue properties of dissimilar welded joints between Ti–6Al–4V and Ti17 alloys

The aim of this study was to evaluate the microstructure, hardness and cyclic deformation behavior of electron beam welded dissimilar joints of Ti–6Al–4V and Ti17 (Ti–5Al–4Mo–4Cr–2Sn–2Zr) titanium alloys. The welding resulted in a significant microstructural change across the joint, with hexagonal close-packed (hcp) martensite α′ and orthorhombic martensite α″ in the fusion zone (FZ), α′ in the heat-affected zone (HAZ) of Ti–6Al–4V side, and coarse β in the HAZ of Ti17 side. A characteristic asymmetrical hardness profile across the dissimilar joint was observed with the highest hardness in the FZ and a lower hardness on the Ti–6Al–4V side than on the Ti17 side, where a soft zone was observed. The dissimilar joint exhibited a lower Young′s modulus and higher cyclic strain hardening exponent than both Ti–6Al–4V and Ti17 base metals (BMs), and had the monotonic and cyclic yield strengths lying in-between those of two BMs with higher values for Ti17 alloy. Both BMs and joint showed essentially symmetrical hysteresis loops and equivalent fatigue life, and exhibited cyclic stabilization at lower strain amplitudes up to 0.6%, while cyclic softening occurred after initial cyclic stabilization at higher strain amplitudes. The initial cyclic stabilization was shortened with increasing strain amplitude. In the Ti–6Al–4V BM fatigued at a high strain amplitude of 1.2%, a short initial cyclic hardening emerged, corresponding to the presence of twinning and its resistance to the dislocation movement. Fatigue failure of the dissimilar joint occurred in the HAZ of Ti17 side where the soft zone was present, with crack initiation from the specimen surface or near-surface defect and crack propagation characterized by typical fatigue striations.

Effect of welding process on the microstructure and properties of dissimilar weld joints between low alloy steel and duplex stainless steel

To obtain high-quality dissimilar weld joints, the processes of metal inert gas (MIG) welding and tungsten inert gas (TIG) welding for duplex stainless steel (DSS) and low alloy steel were compared in this paper. The microstructure and corrosion morphology of dissimilar weld joints were observed by scanning electron microscopy (SEM); the chemical compositions in different zones were detected by energy-dispersive spectroscopy (EDS); the mechanical properties were measured by microhardness test, tensile test, and impact test; the corrosion behavior was evaluated by polarization curves. Obvious concentration gradients of Ni and Cr exist between the fusion boundary and the type II boundary, where the hardness is much higher. The impact toughness of weld metal by MIG welding is higher than that by TIG welding. The corrosion current density of TIG weld metal is higher than that of MIG weld metal in a 3.5wt% NaCl solution. Galvanic corrosion happens between low alloy steel and weld metal, revealing the weakness of low alloy steel in industrial service. The quality of joints produced by MIG welding is better than that by TIG welding in mechanical performance and corrosion resistance. MIG welding with the filler metal ER2009 is the suitable welding process for dissimilar metals jointing between UNS S31803 duplex stainless steel and low alloy steel in practical application.

A Comparison of Creep Rupture Strength of Ferritic/Austenitic Dissimilar Weld Joints of Different Grades of Cr-Mo Ferritic Steels

Evaluations of creep rupture properties of dissimilar weld joints of 2.25Cr-1Mo, 9Cr-1Mo, and 9Cr-1MoVNb steels with Alloy 800 at 823 K were carried out. The joints were fabricated by a fusion welding process employing an INCONEL 182 weld electrode. All the joints displayed lower creep rupture strength than their respective ferritic steel base metals, and the strength reduction was greater in the 2.25Cr-1Mo steel joint and less in the 9Cr-1Mo steel joint. Failure location in the joints was found to shift from the ferritic steel base metal to the intercritical region of the heat-affected zone (HAZ) of the ferritic steel (type IV cracking) with the decrease in stress. At still lower stresses, the failure in the joints occurred at the ferritic/austenitic weld interface. The stress-life variation of the joints showed two-slope behavior and the slope change coincided with the occurrence of ferritic/austenitic weld interface cracking. Preferential creep cavitation in the soft intercritical HAZ induced type IV failure, whereas creep cavitation at the interfacial particles induced ferritic/austenitic weld interface cracking. Micromechanisms of the type IV failure and the ferritic/austenitic interface cracking in the dissimilar weld joint of the ferritic steels and relative cracking susceptibility of the joints are discussed based on microstructural investigation, mechanical testing, and finite element analysis (FEA) of the stress state across the joint.