Effect Of Post-weld Heat Treatment Research Articles

Effects of PWHT on the Residual Stress and Microstructure of Bisalloy 80 Steel Welds

Quenched and tempered (Q & T) steels have numerous applications, particularly in the defence industry with welding as the main fabrication route. Since welding imparts stresses due to thermal gradients development during welding, plus the fact that the Q & T fabricated structures are expected to function in a complex loading environment, it is critically important to relax the welding stresses before exposing the parts to service conditions. The present study reports on the generated residual stresses when Bisalloy 80 is welded by pulsed gas metal arc welding (GMAW-P) and verifies the effects of post-weld heat treatment (PWHT) on the microstructural changes, removal or reduction of residual stresses and the resulting mechanical properties of the welded Q & T steel joints. Neutron diffraction was utilized to measure the residual stresses in the as-welded and after PWHT of the Bisalloy 80 steel weldments. High levels of tensile residual stresses reaching to the yield strength of the weld metal were present (642 ± 24 MPa) in the as-welded joints but were substantially reduced after PWHT (145 MPa ± 21 MPa, which is ~23% of the yield strength of the weld metal). PWHT led to microstructural changes in different regions of the parent and weld metals, including the formation of coarsened polygonal ferrite grains and bainitic ferrite laths. This finding is in line with hardness measurements, where hardness reductions were evident in the heat-affected zone (HAZ) and the weld metal (WM) of the heat-treated specimens.

Effect of heat input and post weld heat treatment on the texture, microstructure and mechanical properties of laser beam welded AISI 317L austenitic stainless steel

In this study, AISI 317L austenitic stainless steel sheets were welded using laser beam welding method and post-welding heat treatment (PWHT) was applied to the joints. The effect of PWHT and welding heat input on texture, microstructure and mechanical properties was examined. According to the results obtained in the study, it was observed that the microstructure of the weld metal of the samples welded with the lowest and highest heat input consisted largely of austenite and a small amount of ferrite grains. Mechanical properties were directly affected by such microstructural changes. With the exception of impact notch results, higher tensile strength and micro-hardness was observed for most welded joints compared to the base metal for heat-treated and non-heat-treated conditions. It was found that the bending strength decreased due to softening of the microstructure after heat treatment. High mechanical properties were achieved in the samples joined with low heat input thanks to the microstructure with finer grains. According to the electron backscatter diffraction result (EBSD); the austenite (FCC) ratio in the base metal and weld metal of the sample welded with the highest heat input was found to be approximately 98% and 92%, while the ferrite (BCC) ratio in the base metal and weld metal was determined as 2% and 8%. It was determined that austenite volume ratio increases with PWHT. Austenite grains showed a random orientation in the base metal, while in the weld metal they showed orientation in the direction of [111] and more often [100]. Generally K–S and N–W orientation relationship (OR) was observed in the samples. In the weld metal of the C4H sample, transmission electron microscopy (TEM) determined the spinodal decomposition of ferrite, but G-phase was not observed.

Heat treatment and heat input effects on the dissimilar laser beam welded AISI 904L super austenitic stainless steel to AISI 317L austenitic stainless steel: Surface, texture, microstructure and mechanical properties

In this study, AISI 904L super austenitic - AISI 317L austenitic stainless steel sheets were successfully welded by laser welding method using six different heat inputs. Welded samples went through 1 h of post-weld heat treatment (PWHT) at 1100 °C and then left to cool at room temperature. The effect of PWHT and welding heat input on surface, texture, microstructure and mechanical properties has been examined. According to the results obtained in the study, it was observed that the weld metal microstructure of the samples welded at the lowest and highest heat input values consisted entirely of austenite (dendritic + interdendritic) grains. With PWHT, Cr23C6 precipitation was observed in both grain boundaries and austenite grains. In addition, austenite as well as dislocation and stacking fault formations were observed in the microstructure. While the highest austenite content was observed in the microstructure of AISI 317L, the content of austenite increased in all samples with PWHT. It was observed that most of the grains that were orientated in the [111] direction were orientated in the direction of [101] and [001] after PWHT. However, the KAM values of the dislocation in grain boundaries decreased with the effect of PWHT. In addition, with the reduction of the ratio of dark grains and the effect of re-crystallisation, (112) <111> components representing austenite grains appeared in FCC/BCC texture. It was identified that due to these textural changes, the tensile strength and resistance to bending of the samples were negatively affected but their toughness was positively affected. AB3 sample with the highest tensile strength, hardness, bending strength and lowest toughness had values of 615 MPa, 214 HV, 1100 N and 57 J, respectively, while these values changed to 550 MPa, 181 HV, 720 N and 60 J with the effect of PWHT. Due to the presence of the chromium-oxide layer, it was identified that the density of O− ion and H− ion was at high levels on the surface of the weld metal. It was identified that the density of these ions decreases with increasing depth, while Fe−, Cr− and Ni− ions increase. Excellent K–S and N–W orientation relationship (OR) was observed between FCC/BCC-structured grains present in the microstructure of without PWHT base metals and weld metal, while Bain OR was also observed in weld metal with or without PWHT. In the microstructure of the base metals with PWHT, there was no OR relationship between grains with FCC/BCC structures.

Texture, microstructure and mechanical properties of laser beam welded AISI 2507 super duplex stainless steel

This study investigates weldability of AISI 2507 super duplex stainless steel (SDSS) sheets with laser welding. The impact of heat inputs and post-weld heat treatment (PWHT) on the mechanical properties, texture, microstructure and the surface of joints were analyzed. The microhardness and tensile strength values of the samples welded with the lowest weld heat input was detected to be greater than samples welded with the high heat input. The highest values for tensile strength, bending force and impact toughness in welded samples have been identified as 891 MPa, 1092 N and 58.4 J respectively. The effect of PWHT caused a decrease in the hardness and tensile strength of all samples, and improved the toughness and ductility properties. While dislocations and stacking faults were observed in the base material microstructure, twinning formation was also detected in the weld metal. Secondary austenite (γ2) and Cr23C6 carbides were also found after heat treatment. Variations in the coincidence site lattice (CSL) boundary proportions and the Schmid factors (SFs) directly affected the mechanical properties. In the 2D- and 3D-orientation distribution function (ODF) base material and weld metal maps, the δ-ferrite and γ-austenite textures performed high-density γ-fiber and α-fiber orientations and a low-density (110) <110> rotated cube component, and showed high-density γ-fiber and low-density α-fiber RD//<110> orientations after heat treatment. When the orientation relationships of the heat-treated sample were examined, Kurdjumov–Sachs (K–S) and Nishiyama–Wassermann (N–W) relationships were determined between the γ/α phases in the base material and weld metal, in addition to these orientation relationships, a occasionally seen (100)γ//(100)α Bain orientation relationship was also found in the non-heat-treated sample. The atomic concentrations of the non-heat-treated and heat-treated weld metals exhibited an increase in the O1s spectrum and decreases in the Ni 2p, Fe 2p, Mo 3d and Cr 2p spectra with increasing sputtering time. Diffusion of H− ion with low density to ferrite and austenite grains on weld metal structure was observed.

Effect of Post-Weld Heat Treatment on the Corrosion Resistance of Super Austenitic Stainless Steel

Seaborne transportation by merchant vessels amounts to more than 90% of the world’s trade volume and it represents about 20% to 30% of the materials generated by the combustion of the total fuel. The International Maritime Organization (IMO) has enforced the use of 0.5% or less low-sulfur fuel oil when operation in all since 2020, and the installation of a scrubber is considered the most realistic alternative in compliance with IMO’s new regulation. However, the desulfurization process unavoidably creates a corrosive environment, and corrosion from it is mainly concentrated on welded materials. To solve the corrosion problem in that area, post-weld heat treatment was applied on Super Austenitic Stainless Steel (UNS N08031) which is commonly used for scrubbers. Upon heat treatment at 1,160 °C or at a higher temperature after welding, microsegregation of welds and base metals was dissolved. As a result, elements were distributed equally and the corrosion resistance increased due to the formation of a uniform oxide film.

Enhancement of tensile properties of gas tungsten arc welds using Cu-coated CoCrFeMnNi filler and post–weld heat treatment

This study investigated the gas tungsten arc (GTA) weldability of cold-rolled CoCrFeMnNi high-entropy alloys (HEAs) using Cu-coated HEA filler, specifically through the application of various post–weld heat treatment (PWHT) temperatures. The GTA weldability of cold-rolled HEA was evaluated by applying the optimum condition of full penetration, and the effect of PWHT was investigated in the temperature range of 973–1173 K. No macro-defects were detected in the weld metal (WM) to which the Cu coated HEA filler was applied. All the PWHT-applied specimens, including the as-welded specimens, were composed of the FCC phase. The Cu component was solid-solutionized over the entire area of the WM and did not form a precipitate. The tensile properties of the as-welded specimens deteriorated in the presence of CrMn oxides. As the PWHT temperature increased, the grain size in the base metal (BM) increased and inclusions in the WM were re-dissolved. Furthermore, by increasing the PWHT temperature, the hardness of the BM decreased significantly by grain growth, and the WM softened slightly owing to the re-dissolution of inclusions. Therefore, the WMs improved the tensile strength and elongation with increasing PWHT temperature. The application of PWHT significantly improved the weldability of the Cu coated CoCrFeMnNi welds.

Effect of post-weld heat treatment on a friction stir welded joint between 9Cr-ODS and CLF-1 steels

Dissimilar-metals welding is essential to construction of a fusion reactor by using advanced blanket structural materials of oxide dispersion strengthened (ODS) steels. In the present study, Dissimilar-metals bonding between 9Cr-ODS and CLF-1 steels was carried out by friction stir welding (FSW). Effect of post-weld heat treatment (PWHT) on microstructure and bonding properties of the joint was investigated. The results show that, quenched martensite was found in the weld metal (WM) after FSW. PWHT at 740-800 °C can recover the microstructure of the WM to tempered martensite. Mid-size particles and nano-particles were observed and analyzed in the WM. Besides, in the WM on the CLF-1 side, recrystallization was found after PWHT. As the PWHT temperature increased, the recrystallization width and grain size grew up. However, the recrystallization in the WM did not degrade but may be beneficial to the bonding properties of the joint due to support ductile deformation during mechanical tests. The recommend PWHT temperature is 740-760 °C for keeping the mechanical properties of the CLF-1 base metal (BM) as that before FSW.

Some studies on dissimilar welds joint P92 steel and Inconel 617 alloy for AUSC power plant application

The Cr–Mo steel containing 9% Cr is generally preferred in producing high-temperature operating components (lower than 620 °C) like steam pipes and headers due to their outstanding combination of elevated temperature mechanical properties and creep strength. The components with an operating temperature of more than 620 °C (superheater and reheaters tubes) are mainly produced using stainless steel or Ni-based superalloy. Hence due to economic aspects of boilers, joining of P92 steel with Ni-based superalloy is inevitable in advanced ultra-supercritical (AUSC) plants. Thus the development of joining technology without diminishing the high-temperature mechanical properties of the weldments becomes essential. The present work introduces the microstructure evolution in gas tungsten arc welded (GTAW) dissimilar joint of P92 steel and Inconel 617 alloy produced by using the P92 filler. The microstructure study along weldments was examined using an optical microscope (OM) and field emission scanning electron microscope (FESEM). The mechanical properties of welded joint and joint integrity were determined by using the microhardness measurement, cross-weld tensile tests, and impact toughness test. The effect of the post-weld heat treatment (PWHT) on mechanical properties and microstructure evolution was also performed. The residual stresses were also examined using the blind hole drilling methods, and the effect of PWHT on the nature and magnitude of the residual stresses were also conducted. The microstructure observation showed the martensitic lath structure in the weld metal, which resulted in poor impact toughness (36 ± 5 J) and high hardness (458 ± 25 HV) of weld metal in the as-welded condition. A considerable increase in impact toughness (90 ± 4 J) and a decrease in hardness (371 ± 11 HV) of weld metal were observed after the PWHT. A wide region of the unmixed zone at the interface of weld metal and Inconel 617 was formed due to the difference in chemical composition and structure. The unmixed zone formation led to the poor tensile properties of the welded joint, and failure was observed both in P92 BM and at the interface of weld metal and Inconel 617 interface. The tensile tested sample failed from the interface region and showed the presence of Ti(C, N) particles, while secondary phase M23C6 particles were obtained from the tensile sample fractured from P92 BM. The impact test results also showed the variation in impact toughness along the weldments. The P92 BM was found the strongest zone, while weld metal was noticed as the weakest zone in terms of impact toughness. The variation in residual stresses was also measured along with the thickness of the plate, and the peak magnitude of the residual stresses was measured in the capping pass, which was compressive in nature.

The Effects of Postweld Processing on Friction Stir Welded, Additive Manufactured AlSi10Mg

Given the limited build volumes for most current additive manufacturing (AM) machines, a method for taking advantage of the unique capabilities offered by AM while combining it with traditional manufacturing methods is needed. Welding of AM-produced components is a solution to this challenge. The objective of this study was to determine the feasibility of using friction stir welding (FSW) to join AlSi10Mg melted with laser powder bed fusion (PBF-L) and examine the effects of postweld heat treatment (HT) and hot isostatic pressing (HIP) on overall joint quality and mechanical performance. Samples were examined using optical microscopy, scanning electron microscopy, hardness testing, and tensile testing. Examination of the samples that underwent a postweld annealing HT revealed cracking along the stir zone and the thermomechanically affected zone (TMAZ) boundary. Examination of the crack revealed evidence of liquation near single-phase silicon precipitates in the TMAZ despite the annealing temperature being 27°C (81°F) below the solidus temperature of the material according to the material specification. Using a calculated pseudobinary phase diagram of AlSi10Mg, the annealing HT was determined to be in the partial liquation regime for AlSi10Mg. The voids and crack formation mechanisms were determined to be caused by constitutional liquation coupled with the unique TMAZ microstructure and stress state. The as-welded and HIP coupons were void and defect free, and FSW was determined to be a feasible method of joining PBF-L aluminum alloys with minimal knockdown in tensile strength.

Effect of post-weld heat treatment on inhomogeneity of mechanical properties and corrosion behavior of rotary friction welded 2024 aluminum alloy joint

The effects of different aging treatment conditions on inhomogeneity of mechanical properties and corrosion behavior of rotary friction welded (RFWed) AA2024 joints were studied by artificial and natural aging treatment. The sliced samples at the center, 0.25R, 0.5R and 0.75R positions were taken along the radius of RFWed joint. After artificial aging and long-term natural aging treatment, the tensile strength and corrosion resistance in different positions of joint tended to be homogeneous. Furthermore, the distribution of elements existed in the interior of grain and grain boundary was homogeneous after artificial aging, which reduced the tendency of intercrystalline corrosion. And pitting corrosion occurred at dynamic recrystallization zone (DRZ), thermo-mechanically affected zone (TMAZ), heat affected zone (HAZ) and base metal (BM). The order of corrosion resistance of each region was inferred from the electrochemical parameters as BM > TMAZ > HAZ > DRZ. With the prolongation of natural aging time, the best corrosion resistance occurred in BM, while the corrosion types of DRZ, TMAZ and HAZ gradually changed from pitting and intergranular corrosion to pitting corrosion mainly.

Microstructural/mechanical characterizations of electron beam welded IN738LC joint after post-weld heat treatment

The effect of post-weld heat treatment on microstructure and mechanical properties of electron beam welded IN738LC joint has been investigated. The fusion zone consists of γ-Ni matrix, bimodal-size γʹ particles, granular MC carbides (Ti-rich) and Cr-rich M23C6 carbide chain in IN738LC joint subjected to post-weld heat treatment. The secondary γʹ particle in fusion zone precipitates and grows ceaselessly with the increased aging time. The coarsening of γʹ particle follows the Lifshiitz-Slyozov-Wagner coarsening theory with a constant coarsening rate of 1.003 × 10−27m3/s. The secondary γʹ particle in base metal shows a similar size with that of fusion zone, but a lower volume fraction (52%) than that of fusion zone (54%). M23C6 carbide is easier to precipitate along high angle grain boundaries. As aging time increases, the morphology of M23C6 carbide changes from discrete granular shape to continuous chain. The thickness of M23C6 carbide also increases dramatically. Owing to smaller grain size and higher solute concentration in fusion zone, more M23C6 carbides form in FZ than that of base metal. With the increased aging time, the tensile strength of IN738LC joint at 900°C decreases gradually, while the elongation of joint firstly increases and then decreases, which is attributed to the increased channel width of γ-Ni matrix. Due to the formation of continuous M23C6 carbide chain, the rupture life of IN738LC joint firstly increases and then decreases as aging time increases. Combined with the mechanical properties and size stability of γʹ precipitates in IN738LC joint, 1125°C/2 h + 850°C/24 h is an optimized post-weld heat treatment regime.

Effects of Post-Weld Heat Treatment on Microstructure and Mechanical Properties of the Brazed Joint of a Novel Fourth-Generation Nickel-Based Single Crystal Superalloy

Effects of Post-Weld Heat Treatment on Microstructure and Mechanical Properties of the Brazed Joint of a Novel Fourth-Generation Nickel-Based Single Crystal Superalloy

Effect of Post-Weld Heat Treatment on Microstructural Evolution and Abrasive Wear of Nanostructured Fe-Based Hardfacing

Effect of Post-Weld Heat Treatment on Microstructural Evolution and Abrasive Wear of Nanostructured Fe-Based Hardfacing

Mechanical Property Improvement in Dissimilar Friction Stir Welded Al5083/Al6061 Joints: Effects of Post-Weld Heat Treatment and Abnormal Grain Growth.

The 5083 and 6061(T6) aluminum (Al) alloys are widely used in transportation industries and the development of structural designs because of their high toughness and high corrosion resistance. Friction stir welding (FSW) was performed to produce the dissimilar welded joint of Al5083-Al 6061(T6) under different welding parameters. However, softening behavior occurred in the friction stir welded (FSWed) samples because of grain coarsening or the dissolution of precipitation-hardening phases in the welding zone. Consequently, this research intended to investigate the effect of the post-weld heat treatment (PWHT) method on the mechanical property improvement of the dissimilar FSWed Al5083-Al6061(T6) and governing abnormal grain growth (AGG) through different welding parameters. The results showed PWHT enhanced the mechanical properties of dissimilar joints of Al5083-Al6061(T6). AGG was obtained in the microstructure of PWHTed joints, but appropriate PWHT could recover the dissolved precipitation-hardening particle in the heat-affected zone of the as-welded joint. Further, the tensile strength of the dissimilar joint increased from 181 MPa in the as-welded joint to 270 MPa in the PWHTed joint, showing 93% welding efficacy.

Effect of Post-Weld Heat Treatment Temperature on the Mechanical Properties and Microstructure of Carbon Steel Base Metal

The effect of post-weld heat treatment (PWHT) on the mechanical properties and microstructure of carbon steel base metal was investigated. MDF A 105, 106-B, 216-WCB, 516-415, and 516-485 carbon steels were employed, and the steels were each subjected to heat treatment with holding temperatures of 610, 650, 690, and 730 ℃ for 8 hours for the simulation of PWHT. The tensile strength and impact toughness of the steels showed a tendency to decrease with increasing holding temperature; this behavior was mainly attributed to the spheroidization of cementite in pearlite and the precipitation of cementite at grain boundaries.

The effect of post-weld heat-treatment (PWHT) and vibratory assisted welding (VAW) on hardness of 304L stainless steels material

The effect of post-weld heat-treatment (PWHT) and vibratory assisted welding (VAW) on hardness of 304L stainless steels material

Effect of Post-Weld Heat Treatment on the Fatigue Behavior of Medium-Strength Carbon Steel Weldments

Railway vehicle makers manufacture the bogie frame by welding medium-strength carbon steel sheets. It has been a long-standing practice to perform post-weld heat treatment (PWHT) to remove welding-residual stress, but rail car manufacturers are moving toward producing bogie frames without PWHT. Since securing the fatigue strength of the bogie frame is essential for vehicle operation safety, it is necessary to systematically evaluate the effects of PWHT on hardness, microstructure, mechanical properties, corrosion, fatigue strength, etc. In this study, small-scale welding specimens and full-size components were produced using S355JR used in general structures, automobiles, shipbuilding, railroad vehicles, etc. The effect of PWHT on material properties-the hardness of the base material, heat-affected zone and weld metal, microstructure, shock absorption energy, yield strength, tensile strength, and fatigue were investigated. When the weld specimen was annealed at 590 °C and 800 °C for 1 h, the yield strength and tensile strength of the specimen decreased, but the elongation increased. For specimens not heat-treated, the parent material’s yield strength, the yield strength in HAZ, and the yield strength of the weld metal were 350 MPa, 345 MPa, and 340 MPa. For specimens heat-treated at 590 °C, they were 350 MPa, 345 MPa, and 340 MPa. For specimens heat-treated at 800 °C, they were 350 MPa, 345 MPa, and 340 MPa. Annealing heat treatment of the specimen at 800 °C homogenized the structure of the weldments similar to that of the base material and slightly improved the shock absorption energy. For specimens not heat-treated, the Charpy impact absorption energies at 20 °C of the parent material and weld metal were 291.5 J and 187 J. For specimens heat-treated at 590 °C, they were 276 J and 166 J. For specimens heat-treated at 800 °C, the Charpy impact absorption energy at 20 °C of the parent material was 299 J. PWHT at 590 °C had the effect of slightly improving the fatigue limit of the specimen but lowered the fatigue limit by 10.8% for the component specimen.

Effect of Post-Weld Heat Treatment on the Solid-State Diffusion Bonding of 6061 Aluminum Alloy

The precipitation-hardenable aluminum alloy 6061 (AA 6061) is favored for aerospace components and automotive parts. However, the tenacious oxide layer on the surface greatly limits the quality and applicability of joining AA 6061. In this study, the joining method of solid-state diffusion bonding was implemented for AA 6061 plates, and the effects of post-weld heat treatment (PWHT) on the joint interface were investigated. The bonding temperatures were within the range of 500–530 °C, and the time periods varied from 30 to 240 min under a static pressure of 5 MPa in a vacuum. The diffusion bonded specimens were subjected to T4- and T6-PWHT to improve the bonding quality. The interfacial microstructure of the joints was analyzed by scanning electron microscopy, and the mechanical properties were evaluated with shear tests. The experimental results showed that the shear strength of the diffusion bonded joint could reach around 71.2 MPa, which was highly dependent on bonding temperature and holding time, and T6-PWHT further enhanced it to over 100 MPa. The effects of PWHT on the diffusion bonded AA 6061 joint were investigated, and the fractography on the sheared surfaces indicated that PWHT-T6 played an important role in enhancing joint strength, which was consistent with the measured shear strength. The sequential PWHT for AA 6061 after diffusion bonding was proven to be feasible for bonding of AA 6061 parts, and the joint strength was sufficient for industrial needs.

Effect of post-weld heat treatment (PWHT) on microstructure and corrosion behavior in ENiCrFe-7 weld overlay cladding materials

Effect of post-weld heat treatment(as-weld, 615℃/16 h and 615℃/48 h) on microstructure and corrosion behavior in ENiCrFe-7 weld overlay cladding materials had been investigated, the results showed that the heat treatment had an obvious influence on microstructure and corrosion properties. As-weld Alloy ENiCrFe-7 exhibited to be compressive residual stress, and it had a lot of homogeneously distributed microstructure defects(e.g. composition segregation), the pits were evenly distributed on the surface of the sample after polarization, its passive current density was the least due to formation of the densest passive film. With increasing heat treatment time to 16 h, the compressive residual stress was rapidly decreased, the degree of Cr-depletion in the dendrites was obviously increased, and a large number of pits were concentrated in the Cr-depletion area. With increasing heat treatment time to 48 h, the compressive residual stress was slightly increased compared with that at heat treatment time of 16 h, both the degree of Cr-depletion in the dendrites and microstructure defects were improved, the looser passive film was formed, general corrosion was mainly performed during polarization.

Dissimilar Laser Welding of Austenitic Stainless Steel and Abrasion-Resistant Steel: Microstructural Evolution and Mechanical Properties Enhanced by Post-Weld Heat Treatment.

In this study, ultra-high-strength steels, namely, cold-hardened austenitic stainless steel AISI 301 and martensitic abrasion-resistant steel AR600, as base metals (BMs) were butt-welded using a disk laser to evaluate the microstructure, mechanical properties, and effect of post-weld heat treatment (PWHT) at 250 °C of the dissimilar joints. The welding processes were conducted at different energy inputs (EIs; 50–320 J/mm). The microstructural evolution of the fusion zones (FZ) in the welded joints was examined using electron backscattering diffraction (EBSD) and laser scanning confocal microscopy. The hardness profiles across the weldments and tensile properties of the as-welded joints and the corresponding PWHT joints were measured using a microhardness tester and universal material testing equipment. The EBSD results showed that the microstructures of the welded joints were relatively similar since the microstructure of the FZ was composed of a lath martensite matrix with a small fraction of austenite. The welded structure exhibited significantly higher microhardness at the lower EIs of 50 and 100 J/mm (640 HV). However, tempered martensite was promoted at the high EI of 320 J/mm, significantly reducing the hardness of the FZ to 520 HV. The mechanical tensile properties were considerably affected by the EI of the as-welded joints. Moreover, the PWHT enhanced the tensile properties by increasing the deformation capacity due to promoting the tempered martensite in the FZ.