Laser-welded Joints Research Articles

Mechanical Characterization and Prediction of Aluminum Alloy Laser Welding Joints Including Roles of Geometries and Porosity

Mechanical Characterization and Prediction of Aluminum Alloy Laser Welding Joints Including Roles of Geometries and Porosity

Investigation of laser beam welding on lap joints of Al/steel dissimilar materials subjected to alternating magnetic field

In this study, magnetically assisted laser beam welding was experimentally carried out on Al/steel dissimilar materials in a lap configuration. Weld morphology, interfacial microstructure, element distribution, precipitated phases and mechanical properties of laser-welded joints were carefully investigated. The strengthening mechanism of Al/steel joints was also explored. The results revealed that good weldments were successfully acquired with the assistance of an alternating magnetic field. The microstructures at interface were mainly constituted by nubbly structures, island-shaped structures and banded structures. Fe-Al compounds at interface were expectedly dispersed due to the magnetic field-driven effect on liquid metal. During laser beam welding, the susceptibility to weld cracking was obviously decreased on the premise of inhibition of the composition segregation. The Fe/Al interface zone was mainly composed of η-Fe2Al5 phase, β2-FeAl phase, ζ-FeAl2 phase and θ-FeAl3 phase. The maximum tensile load and elongation of the tested joints subjected to a magnetic field reached 122.22 % and 145.76 % of joints without magnetic field, respectively. Performance enhancement of welded joints was mainly attributive to the effective regulation of weld microstructure and composition during magnetically assisted laser beam welding.

Microstructure evolution and formation mechanism of γ-TiAl/Ni-based superalloy laser-welded joint with Ti/V/Cu filler metals

Laser welding of dissimilar γ-TiAl alloy to Ni-based superalloy with Ti/V/Cu filler metals was applied and well formed joint was obtained. The weld zone consisted of AlNi2Ti, CuNiTi, (V,Cr) solid solution (ss) and (Cu,Ni)ss. The γ-TiAl interface zone composed of AlCuTi and AlCu2Ti. The microstructure evolution and formation mechanism of the weld zone and γ-TiAl interface zone were discussed in detail. Mechanical testing of the joints revealed that the average tensile strength was 170 MPa and the fractured joint passed through the weld zone and γ-TiAl interface zone.

Quasi-Continuous Wave Pulsed Laser Welding of Copper Lap Joints Using Spatial Beam Oscillation.

Laser beam welding of copper (Cu) using near-infrared radiation is extremely challenging due to its high thermal conductivity and large laser reflectivity. In the present study, the challenges and benefits of using spatial beam oscillation during quasi-continuous wave (QCW) pulsed laser beam welding of 0.4 mm Cu to 1 mm Cu in lap joint configuration are presented. This work demonstrates how laser beam oscillating parameters can be used to control the laser weld quality and laser weld dimensions for Cu-Cu joining. Compared to a non-oscillated laser beam, welds made using laser beam oscillation showed fewer spatters, porosities, and better surface quality. Four levels of oscillating amplitudes (0.2 mm, 0.4 mm, 0.6 mm, and 0.8 mm) and oscillating frequencies (100 Hz, 200 Hz, 300 Hz, and 400 Hz) were compared to reveal the effect of beam oscillation parameters. The weld width was mainly controlled by oscillating amplitude, while weld penetration was affected by both oscillating amplitude and frequency. As the oscillating amplitude increased, the weld width increased while the weld penetration decreased. Increasing the oscillating frequency reduced the weld penetration but had a negligible effect on the weld width. The maximum tensile force of approximately 1944 N was achieved for the joint with a high width-to-depth ratio with an oscillating amplitude of 0.8 mm and an oscillating frequency of 200 Hz.

Investigating the mechanical properties and fusion zone microstructure of dissimilar laser weld joint of duplex 2205 stainless steel and A516 carbon steel

Laser welding of dissimilar A516 low carbon steel and duplex stainless steel was conducted to evaluate the effect of fiber laser welding parameters (e.g., laser power, welding speed, nozzle distance and beam deviation) on the responses of tensile strength, depth of the melt pool, microstructure, temperature near the melt pool and melt pool hardness. The maximum tensile strength of 500 MPa and 18 percent elongation were obtained at the laser power of 400 W, welding speed of 300 mm/min and the focal point. The absorbed power of laser and linear speed of welding had the most notable impact on the tensile strength of the weld. The fusion zone microstructure was composed of a combination of ferrite–austenite distribution from duplex stainless steel (DSS) based on different cooling and heating cycles. During the nucleation process, ferrite grains were transformed to austenite grains from different areas of the fusion zone. Also, the weld fusion zone microstructure at A516 side was composed of fully martensitic structure, according to the higher heat input upper critical temperature of steel (AC3), thereby leading to rapid cooling. The EDS analysis also showed that the Fe percentage was continually reduced at the fusion line from A516 to DSS, although Ni and Cr were distributed at the fusion zone with some minor changes of weight percentage. Therefore, Cr and Ni had a crucial effect on elemental alloy composition in this laser welding process. The ductility of the A516 fracture surface with bigger and deeper fracture dimples was caused by applying higher laser energy density, which effectively improved the fracture ductility of the welded samples.

Effect of post-weld heat treatment on the microstructure and mechanical properties of laser-welded joints of SLM-316 L/rolled-316 L

Abstract Connecting small pieces of parts manufactured by Selective Laser Melting (SLM) and traditional formed parts into large structural component by using welding technology provides a high-efficiency and low-cost way for expanding additive manufacturing technology. SLMed parts usually exhibit similar or superior tensile strength but lower ductility compared to that of cast or rolled ones due to the rapid cooling and cyclic heating deposition characteristics. What about the weldability of the dissimilar joints of SLMed parts and rolled ones? Whether the properties of the welded joints can be improved by heat treatment under the premise of ensuring the reliability of the joint is unclear. The weldability and the effect of heat treatment temperature on the microstructure and properties of laser-welded joints of SLM-316 L/rolled-316 L are studied in this article. The results show that the joints exhibit good weldability without obvious defects. The low temperature annealing treatment had no significant effect on the multilayered structure and columnar austenite grains, but only changed the morphology and content of ferrite within the grains leading to the slight increase of elongation but decrease of material strength. The corrosion performance was almost unaffected. After solution annealing above 1,000°C, the ferrite was nearly dissolved in the austenite matrix. The austenite recrystallized and the multilayered structure was destroyed, which resulted in decrease of material strength, a slightly improvement in corrosion resistance, and the elongation was greatly enhanced. After the detailed study, it was concluded that the post-weld heat treatment provided an effective way for improving the overall performance of the SLM-316 L/rolled-316 L dissimilar joint.

Microstructural characterization and mechanical properties of Ti3Al-Nb/Ni-based superalloy laser-welded joints with different type of V/Cu composite interlayers

Dissimilar welding of Ti3Al-Nb (Ti-24Al-17Nb) alloy and Ni-based superalloy with different type of V/Cu composite interlayers was performed by laser welding. Detailed microstructural characterization and mechanical properties of the laser-welded joints were investigated. The results indicated that laser welding can be achieved by using the three types of different V/Cu composite interlayers (Type I-0.2 mmV/0.2 mmCu, Type II-0.2 mmV/0.4 mmCu and Type III-0.2 mmV/0.6 mmCu). However, the type of V/Cu composite interlayers has a great influence on the composition distribution, microstructure and mechanical properties of the joints. When Type I was used, the dissimilar weld zone displayed mainly equiaxed and dendrite with fine grain size, and micro-crack was found in the weld. When Type II was used, the weld zone mixed of fine grain region (V-rich phase and Cu-rich phase) and coarse grain region (dendrite V-based solid solution and granular Cu-based solid solution in two-phase separation state). When Type III was used, the weld zone was mainly composed of large Cu solid solution, spherical Ni2V, Ni2V3 and unmelted V layer. The maximum room/high (873 K) temperature tensile strength of the joints was 312 MPa/240 MPa, which was obtained by using Type II. All the joints fractured at the interface on Ti3Al-Nb alloy side, indicating that the interface zone intermetallics were the main factor of affecting the mechanical properties of the joints. Moreover, the interface reaction layer between Ti3Al-Nb and unmetled V layer was also a weak link of Type III joint.

Formation mechanism of direct laser welding joint between CFRTP and Ti-6Al-4V

• PEEK-CFRTP and Titanium alloy as the lightweight materials are used in this research. • Laser welding technology as the heat source to join the dissimilar materials. • Focused Ion beam is used to prepare TEM samples of the joint interface. • Joint formation mechanism is carried out by phase analysis and reaction process. Ti-6Al-4V and Joining fiber reinforced polyether ether ketone resin matrix composite (PEEK-CFRTP) were joined directly by laser welding process. The joint microstructures and phases were analyzed. Results showed that the shear strength could reach 56.3kN/mm. Bubbles and cracks were found in joints, which impaired the strength of joint. The 'Anchor-shaped' structures at interface were also formed to strengthen the joint as the melted resin flowed into surface gap of titanium alloy. The microstructures showed that TiOF2, TiC, VC and the solution (Ti,V)C were found to form the joint. Finally, the joint formation mechanism was released according to the phased generated and joint microstructures.

Predicting laser penetration welding states of high-speed railway Al butt-lap joint based on EEMD-SVM

The Al butt-lap joints are widely applied in China Railway High-speed (CRH) trains body joints. However, the gaps caused by the thermal deformation in Al butt-lap joints lead to the lack penetration or over penetration. To predict the penetration state of laser welds in Al butt-lap joints with different gaps, this work investigated the correlation between the plasma plume morphology and penetration state monitored by high-speed imaging system and the vertical gap and horizontal gap were utilized as intermediary. The ensemble experience mode decomposition (EEMD) was used to obtain the frequency features of plasma plume morphology. A support vector machine (SVM) model combined with EEMD was then established to classify the different penetration state, which adopted the original signals at time-domain and the mode decomposition signals at frequency-domain as input. The EEMD-SVM accuracy of 97.98% was the highest among the EMD-SVM of 86.44% and the SVM of 58.15%. The EEMD-SVM obtained both high Accuracy and Recall when the quantity of positive and negative samples were utmost different. The classification of the EEMD-SVM model was the most superior among the EMD-SVM model and SVM model. This proposed method provided a novel and accurate approach to perform process monitoring and penetration defects detection during laser welding of butt-lap joints.

Microstructure and Mechanical Properties of Laser-Welded Joint of Tantalum and Stainless Steel

Bimetallic components welded by Ta and stainless steel have great promise for engineering applications, but there is relatively little relevant research. In this study, 0.6 mm-thick Ta and 304L stainless steel plates were laser welded, and the forming characteristics, microstructure, and mechanical properties of the welded joints were analyzed. First-principles calculations were also performed to explore the structural stabilization mechanisms of the two intermetallic compounds, TaFe2 and TaCr2, in terms of mechanical properties as well as electronic structure. The results showed that the weld surface was smooth and free from any defects. Fe-based solid solutions formed grains, while TaFe2, TaCr2, and some Fe-based solid solutions formed intergranular and eutectic structures. In addition, due to the presence of the brittle phases of TaFe2 and TaFe, the microhardness of the weld area can reach 650HV, with an average hardness of 530HV, which is much higher than that of the base material. The tensile shear of the joint at room temperature was 154.77 N/mm, and the fracture occurred in the weld zone on the steel side, showing brittle fracture. TaFe2 is a brittle intermetallic compound, while TaCr2 is ductile. Both TaFe2 and TaCr2 systems have dual properties of metallic and covalent bonding within them, and metallic bonding dominates.

Effect of Dynamic Preheating on the Thermal Behavior and Mechanical Properties of Laser-Welded Joints.

The high cooling rate and temperature gradient caused by the rapid heating and cooling characteristics of laser welding (LW) leads to excessive thermal stress and even cracks in welded joints. In order to solve these problems, a dynamic preheating method that uses hybrid laser arc welding to add an auxiliary heat source (arc) to LW was proposed. The finite element model was deployed to investigate the effect of dynamic preheating on the thermal behavior of LW. The accuracy of the heat transfer model was verified experimentally. Hardness and tensile testing of the welded joint were conducted. The results show that using the appropriate current leads to a significantly reduced cooling rate and temperature gradient, which are conducive to improving the hardness and mechanical properties of welded joints. The yield strength of welded joints with a 20 A current for dynamic preheating is increased from 477.0 to 564.3 MPa compared with that of LW. Therefore, the use of dynamic preheating to reduce the temperature gradient is helpful in reducing thermal stress and improving the tensile properties of the joint. These results can provide new ideas for welding processes.

Structural characterization of a composite joint prepared during laser welding of Ti–22Al–27Nb intermetallic alloy with an interlayer of Cu-Hf-Ni-Ti-Zr high entropy bulk metallic glass

The advent of high entropy alloys (HEAs) has provided scientific solutions to material related problems of grave importance. High-temperature embrittlement (HTE) in the laser welded joint (LWJ) of titanium aluminides is one of the challenges, known to impede the prevalent applications of this novel alloy system. In the current research work, a sandwich-structured composite joint of an intermetallic based alloy (Ti–22Al–27Nb) with a high entropy bulk metallic glass (HE-BMG) composed of Cu, Hf, Ni, Ti and Zr was welded through laser beam. The adulteration of LWJ with HE-BMG resulted into evolution of finite microregions in the fusion zone (FZ) through heterogeneous nucleation. The FZ comprised fine-grained B2 phase with greater fractions of high angle grain boundaries (HAGBs) and lower degree of local area misorientations (LAM). The crystal texture of B2 phase in the FZ abetted the plastic deformation at room as well as high temperature (650 °C), as the Schmid factor “m” for ≥ 99% of {1 1 0} <1 1 1> slip system of B2 remained greater than 0.38. The high-resolution transmission electron microscopy revealed the presence of nano-sized composite regions (NCRs), composed of crystalline/non-crystalline structure. These NCRs remained stable at 650 °C and inhibited the nucleation of O phase along B2 grain boundaries (GBs). The percentage elongation of HE-BMG supplemented LWJ of Ti–22Al–27Nb was improved by 28.19 and 31.34% at room temperature and 650 °C, respectively. The dilution of FZ with HE-BMG contributed a significant increase in tensile ductility at room as well as high temperature.

Improving the Quality of Laser-Welded Butt Joints of Metal–Polymer Sandwich Composites

Sandwich panels are promising composite materials, although the possibilities for their thermal joining are limited due to the degradation of the polymer core at elevated temperatures. The purpose of this study is to improve the quality of the butt joints in metal–polymer sandwich composites performed by laser welding. A pulsed Nd:YAG Rofin StarWeld Performance laser was used to perform the two-sided welding of the metal–polymer three-layer composite material. On each of the two sides of the material, a welded joint was made with partial penetration of the covering steel sheets, which was considered a prerequisite for preventing the degradation of the core polymer layer. The energy density of the laser irradiation was redistributed by increasing the diameter of the laser spot. The structure of the welded joints was examined using a polarized optical microscope and a scanning electron microscope. It was determined that the laser treatment resulted in a partial penetration weld on each of the two covering metal sheets of the material, reaching a depth of more than 50% of the sheet’s thickness without damaging the polymer. The welding area consisted of two zones, one being the weld metal and the other the heat-affected zone. As a result of relatively rapid heating and cooling cycles, fine-dispersed structures were formed in the heat-affected and remelted zones. The performed tensile tests showed that the strength of the welded area was about 80% of that of the base material.

Formation Mechanism and Control of Solidification Cracking in Laser-Welded Joints of Steel/Copper Dissimilar Metals

The solidification cracking behavior in laser welds of steel/copper dissimilar metals was systematically investigated. T2 copper and SUS304 stainless steel were used in the study. The results showed that the occurrence of solidification cracking in welds was the synergistic effect of ε phase liquation, inclusions and composition segregation. During the welding process, the liquation of grain boundaries substantially reduced the cohesion between adjacent grains, as well as the resistance for intergranular crack propagation. The composition segregation inside the grains could induce lattice distortion, thus reducing the plastic deformation capacity of the material itself and concurrently increasing the susceptibility to cracks. In addition, an effective solution for inhibiting solidification cracking was proposed by using an oscillating laser, and the inhibition mechanism was further discussed. Laser oscillating welding significantly promoted grain refinement, solute diffusion and the formation of uniformly distributed ε-Cu precipitated phases in welds. It can improve the intergranular bonding, reduce the susceptibility to solidification cracking and increase the resistance to plastic deformation. The tensile strength of joints using laser oscillating welding is 251 MPa, 35.7% more than 185 MPa using laser welding. Meanwhile, the strain of joints using laser oscillating welding is 3.69, a 96% increase compared to 1.88 using laser welding.

Microstructure-based finite element analysis of mesoscale strain localization and macroscopic mechanical properties of aluminum alloy 2024 laser weld joint

The microstructure and residual stress can be modified by laser welding, which significantly affect the strength and ductility of materials. In this work, a microstructure-based finite element model is established to investigate the mesoscale strain localization and the macroscopic mechanical properties of the 2024 aluminum alloy laser weld joint. The residual stress in different welding processes is predicted, and its effect on the elastic-plastic constitutive model of constituent phases is evaluated. The stress-strain curves of α-Al phase and eutectic phase are calculated using instrumented indentation method. Actual microstructure graphs of the joints are used as the representative volume elements in the model. The mesoscale strain distribution, macroscopic deformation response and the damage initiation are predicted quantitatively during uniaxial tensile deformation. The model is validated by comparing with experimental results, i.e., fusion profile, distortion, strain localization bands, tensile test curves, and good agreements are achieved. It is found that the strain and stress in the constituent phases of the fusion zone are extremely inhomogeneous. There are significant strain localization bands in the α-Al phase and high stress concentration zones in the eutectic phase. The dendritic arm spacing and eutectic phase size decrease, and the percent of eutectic increases during high power matching with high welding speed within certain limits. In this case, the bearing capacity of eutectic phase increases, and the strain inhomogeneity decreases. As a result, the strength (358.8 MPa) and ductility (6.21%) of the joint can be increased by the optimized laser power (5 kW) and welding speed (140 mm/s).

Failure behavior of copper Laser-Welded joints in lap shear specimens

In this study, the failure behavior of laser-welded (LWed) lap shear (LS) specimens in copper (Cu) sheets with unequal thickness has been studied through experimental and numerical approaches. LWed LS specimens with unequal thickness represented the tab-to-electrode joints of batteries in a module. Quasi-static tensile testing has been performed for studying the load–displacement curves, failure loads, and failure modes of LS specimens and the stress–strain curve of Cu. Microstructures and failure modes of LWs have been examined by exploring the micrographs before and after the failure. Necking failure was observed at the heat affected zone (HAZ) in the upper right sheet of LWed LS specimens. Microhardness distributions of LWs were obtained to estimate the stress–strain curves of the fusion zone (FZ), HAZ, and base metal (BM). Based on the stress–strain curves, a two-dimensional plane strain finite element model has been developed for LWed LS specimens. In order to develop a damage criterion for finite element models to simulate the failure mode of LWed LS specimens, a series of quasi-static tensile tests for one shear, one smooth, and four notched specimens made of Cu were conducted to derive the equivalent plastic strains at the onset of damage ε¯Dpl and the corresponding triaxialities η. A damage criterion of BM (Cu) comprised of ε¯Dpl and η was developed. Then a damage criterion of HAZ where the necking failure occurred was estimated based on the damage criterion of BM and the maximum values of ε¯Dpl and η in HAZ derived by the finite element model subjected to the failure load. Finally, it has been concluded that based on stress–strain curves of FZ, HAZ, BM, damage criterion of HAZ, computational simulations of failure behavior of LWed LS specimens are in good agreement with the experimental results..

Remote laser welding of Zn coated IF steel and 1050 aluminium alloy: processing, microstructure and mechanical properties

The integrity of steel-aluminium dissimilar alloy joints is dependent on the intermetallic phases (IMCs) and the extent of the bonding area. The excessive growth of brittle AlxFex IMCs within the weld pool and interfaces is disadvantageous due to the initiation and propagation of hot and cold cracking during the solidification. The purpose of this work was to assess the development of Remote Laser Welded (RLW) joints of Zn coated interstitial free (IF) steel to 1050 aluminium alloy, which can be used in cooling circuits and electrical connectors in automotive applications. Welding experiments with variable RLW parameters (power, welding speed and focal offset) were performed to study the formation of IMCs and impact of joint integrity. Results showed that while in conduction mode (at power densities of 0.13–0.18 MW/cm2) three IMCs were identified through SEM/EDX and EBSD: η – Al5Fe2, κ – AlFe3 and θ – Al13Fe4 which possessed nano-hardness indentation values of approximately 12, 5 and 5 GPa, respectively; they formed in a non-continuous interfacial layer, the weld pool composition remained homogenous, and cracking was minimal. On the contrary, in keyhole mode (at power densities of 0.16–0.40 MW/cm2) welded samples produced a continuous and thick IMC layer, continuous and/or excessive cracking and an inhomogeneous weld pool composition due to the excessive mixing of steel and aluminium, of up to 10 wt.% of Al in the weld pool. The nominal lap shear strength for the sample produced in conduction mode was of 77%, with respect to the weakest joint material (Al). This work found a close link between the welding mode and weld pool chemistry which significantly determined the IMCs distribution and thickness, extent of cracking within the weld pool and mechanical properties.

Study on shear buckling failure of laser-welded dissimilar aluminum alloy (Al-Li-2099/Al-Li-S4) stiffened panel

Laser welding of L-shaped aluminum alloy joints is of great significance in lightweight and efficient manufacturing of thin-wall reinforced aerospace structures. Shear performance is an important reference index for the structural design of aluminum alloy-reinforced panels. In this study, in-plane shear experiments of a continuous double-sided laser welded dissimilar Al-Li alloy (Al-Li-2099/Al-Li-S4) stiffened thin-walled panels were carried out. The deformation and buckling mode evolution of the stiffened panel were measured by the combination of fringe projection profilometry and strain gauge measurement. The results show that in the macroaspect, the stiffened panel first exhibits local skin buckling and then develops into overall buckling along the diagonal tensile direction. Finally, the stiffened panel shows weld desoldering failure. Metallographic examination and scanning electron microscopy were performed on the L-shaped joints at different positions of the stiffened panel. The microstructure observation shows that the weld was composed of a nondendritic equiaxed zone, a columnar dendritic zone, and an equiaxed dendritic zone. The failure mode of the weld is mainly brittle fracture with a small amount of shear dimples, indicating that the welded seam of the stiffened panel under the shear load is tensile shear coupling. After the force reaches material strength, the crack nucleates in the weld and extends along the weld until it penetrates the whole weld. This shows that the mechanical properties of the weld microstructure are closely related to the macroshear properties of the stiffened panel.

Influence of low temperatures on mechanical behavior of laser welded dual phase steels

Low-temperature tensile properties of similar and dissimilar laser-welded joints of dual phase (DP) steels were investigated. DP steels with ultimate tensile strengths of 800 and 1000 MPa were laser welded in similar and dissimilar configurations. The microstructures of the welded joints were characterized, and the welds were tensile tested at temperatures between −40 and 20 °C. Tensile and yield strengths increased as the temperature decreased. However, the DP800-DP1000 dissimilar welded joints exhibited reduced elongation, strength, and absorbed energy when compared to the DP800-DP800 and DP1000-DP1000 similar welded joints throughout the tested temperature range. An in-depth comparison of the deformation mechanisms and failure modes in welds were performed, which showed that the strain gradient for the dissimilar DP800-DP1000 welds is significantly more severe when compared with welds made of similar material combinations (DP800-DP800 and DP1000-DP1000). In addition, the general trend in fracture energy observed in welded similar joints of DP800-DP800 exhibit a decrease with decreasing temperature from 0 to −40 °C, while DP1000-DP1000 joints exhibit an increase in fracture energy as the temperature decreased from 0 to −40 °C. However, the dissimilar DP800-DP1000 joint exhibited relatively consistently lower fracture energy throughout the testing temperatures. The elongation of DP800-DP800-welded joints increased with increasing temperature while the changes in the elongation of welded DP800-DP1000 and DP1000-DP1000 were relatively small. Energy dispersive spectra analysis revealed higher percentages of interstitial atoms, which explains the fluctuating trends seen in the tensile properties of the materials at different deformation temperatures

Stress and distortion of the 10 mm thick plate EH40 and 316L different butt joints in 10 kW laser welding

Residual stress has a negative influence on the service life of different welded joints between high-strength steel and stainless steel, especially in corrosive environment, it is very easy to cause fracture failure of welded joints. In this study, three types of medium-thick plate butt joints in single-pass full penetration laser welding, including EH40 & 316L, EH40 & EH40 and 316L & 316L butt joints, were deeply studied and verified by thermo-elastoplastic finite element method and experiments. The peak exponentially increasing double cone heat source model was used to calculate the transient temperature field. The relevant data of longitudinal, transverse residual stresses and angular distortion in three cases were extracted for comparative analysis. At the same time, the influence of the same material and different materials on the evolution mechanism of nodes stress in the weld was also discussed. It had been found that the geometric profile average error between the simulation and experiment in three cases was less than 0.5%. The stress state changes of the weld and its vicinity nodes in EH40 & 316L butt joint were faster than EH40 & EH40 and 316L & 316L butt joints. Compared with the welded joints of the same material, the welded joints of EH40 and 316L in the weld and its vicinity were remarkable differences in transverse residual stress, equivalent residual stress and angular distortion. The transverse residual stress gradient value of the EH40 side in EH40 & 316L was almost twice that of EH40 & EH40. The mismatch material properties of EH40 & 316L aggravated the generation of transverse tensile residual stress on the EH40 side. The results obtained in the current study were beneficial to the assessment of the integrity in the butt joints and the control of potential risks.