Post-weld Heat Treatment Parameters Research Articles

Effect of Post-Weld heat treatment on residual stress in deck-rib double-side welded joints and process optimization

Post-weld heat treatment (PWHT) is expected to release the welding residual stress (WRS) of deck-rib double-side welded joints in orthotropic steel decks (OSDs). In this paper, the WRS distribution of deck-rib double-side welded joints before and after PWHT is evaluated by hole drilling method and numerical simulation, and the effect of PWHT parameters on WRS relaxation is further compared, and reasonable parameters are suggested. Based on the principle of WRS relaxation by PWHT, the feasibility of secondary continuous PWHT was explored. The results show that PWHT can effectively release the WRS and make the distribution more uniform. Extending the heat preservation time and increasing the temperature can release more WRS, and the heating and cooling rate has little influence on the WRS, so it is recommended to use the specified maximum value. The effect of secondary continuous PWHT is slight, and it is not recommended for use.

Residual stress relief strategy in thick steel weldments via local induction heat treatment: Simulation and neutron diffraction experiment

This study investigated the effect of local induction post-weld heat treatment (PWHT) on residual stress relief in thick submerged arc welded steel plates. A combination of numerical and neutron diffraction methods was used to examine the effect of various PWHT parameters, such as annealing temperature and holding time, on the relief of residual stress in welded plates with various thicknesses. A sequentially coupled thermal–mechanical finite element model was used to calculate the residual stress distribution in welded AH36 steel plates before and after PWHT. The model was validated by comparing its predictions with the experimental measurements, and the results showed good agreement. The residual stress of the thick welded plates was effectively reduced via PWHT with local induction. The primary mechanism for this stress release was identified as stress relaxation caused by creep strain. Furthermore, a process map was established considering the PWHT conditions and plate geometry. This map provides a means of determining the optimal PWHT conditions to achieve desired stress reduction levels.

Investigation on post-weld heat treatment (PWHT) inputs for controlling average fusion zone hardness in fibre laser-welded modified 9Cr–1Mo steel

Post-weld heat treatment (PWHT) generally relieves stress and enhances weldments’ mechanical properties. Optimisation of PWHT parameters is very much needed to control the process parameters for achieving the desired property requirements. In this research, the PWHT parameters for laser-welded P91 steel were optimised using the response surface methodology-based Box–Behnken methodology. Tempering temperature, heating rate and holding time are considered the input parameters and using analysis of variance (ANOVA), their impact on average fusion zone hardness has been analysed. The results indicate that the hardness values are highly influenced by temperature followed by holding time. A parametric combination of 780°C tempering temperature, 6 hours holding time, and 200°C/h heating rate have evolved as the optimal solution. The autogenous nature of the welding process resulted in a heterogeneous microstructure with untempered lath martensite structure showing precipitate dissolution in the as-welded fusion zone, ultimately resulting in a high average fusion zone hardness of 502 HV0.3, whereas PWHT with the optimal solution resulted in an average fusion zone hardness value of 252 HV0.3. The decrease in hardness value followed by heat treatment is primarily due to the tempering process, which resulted in precipitation within and over the grain boundaries. The validation experiment result using the optimum combination of parameters has been observed to be aligned significantly with the expected values, indicating the adequacy of the developed model.

Investigation of stress relief crack susceptibility of CrMoV steels coarse grain HAZ via simulation of uniaxial stress conditions during PWHT

Creep-resistant steels such as the 13CrMoV9-10, used in the construction of thick-walled pressure vessels, are most commonly submerged arc welded (SAW). These steels can develop stress relief cracks (SRC) if the mandatory post weld heat treatment (PWHT) is performed improperly. Current PWHT parameters, such as heating rate and holding time at a specific holding temperature, are based on both empirical experience and conventional free shrinking welding experiments to characterize the SRC-susceptibility of the weld. These cannot adequately depict the higher residual stresses caused by the structurally induced stiffness of the surrounding construction.This study discusses the development of a repeatable, precise, and time-efficient methodology to study the effects of different stress levels and heating rates on the SRC susceptibility of the coarse grain heat-affected zone (CGHAZ). For that purpose, samples were thermically treated to simulate a coarse grain heat-affected zone (CGHAZ) and subsequently exposed to representative levels of stress during the heating phase of a PWHT. The recorded stress and heating rate–dependent strains were mathematically analyzed via curve tracing/calculus to identify interdependent effects. This procedure facilitates the measurement of material characteristics such as carbide growth on grain boundaries at the µm-scale via an integrated value over the entire sample volume. The first and second derivatives show a slight, precipitate-dependent, increase in hardness of the sample, depending on the heating rate and applied stress. This new methodology generates an improved assessment of the SRC susceptibility of SAW microstructures of creep-resistant CrMoV steels.

Post-Weld Heat Treatment of S690QL1 Steel Welded Joints: Influence on Microstructure, Mechanical Properties and Residual Stress

During the manufacturing of welded structures, some degree of residual stresses occurs. The classic approach to residual stress reduction is Post-Weld Heat Treatment (PWHT). In the case of structural grade mild steels, the thermal process is well established. In case of S690QL1 High Strength Steel (HSS), which is manufactured using the Quenching and Tempering (QT) process considered in this paper, only limited PWHT treatment is possible without deterioration of mechanical properties. Since this steel grade is susceptible to subsequent heat input, the challenge is to establish adequate PWHT parameters, achieving residual stress reduction while retaining sufficiently high mechanical properties. The paper considers X joint welded HSS steel plates with slightly overmatching filler metal. The welded coupon is prepared and subjected to PWHT treatment. The research on the influence of heat treatment was performed using the four different PWHT cycles and initial As-Welded (AW) material condition. The authors proposed those PWHT cycles based on available resources and the literature. Process holding temperature is considered the variable parameter directly related to the behaviors of material properties. The methodology of welded joint analysis includes experimental testing of mechanical properties, metallographic examination, and residual stress quantification. Testing of mechanical properties includes tensile testing, Charpy V-notch impact testing, and hardness testing in scope of complete welded joint (BM + HAZ + WM). Metallographic examination is performed in order to characterize the welded joint material in relation to applied PWHT cycles. In order to quantify residual stresses, all heat-treated samples were examined via the X-ray diffraction method. Mechanical properties testing determined that an increase in PWHT cycle holding temperature leads to degradation of tested mechanical properties. For specific zones of the welded joint, the decreasing trend from AW condition to Cycle D (max. 600 °C) can be quantified. Based on representative specimens comparison, strength values (BM ≤ 5.7%, WM ≤ 12.1%, HAZ ≤ 20%), impact testing absorbed energy (BM = 17.1%, WM = 25.8%, FL = 12.5%, HAZ = 0.6%), and hardness values (BM = 4.1%, WM = 3.2%, CGHAZ = 16.6%, HAZ = 24.2%) are all exhibiting decrease. Metallographic examination, using the light microscopy, after the exposure to PWHT thermal cycles, did not reveal significant changes in the material throughout all specific welded joint segments. Average relative reduction in residual stress in correlation with PWHT temperature can be observed (AW = 0%, Cycle A (max. 400 °C) = 72%, Cycle B (max. 530 °C) = 81%, Cycle C (max. 550 °C) = 93% and Cycle D (max. 600 °C) = 100% stress reduction). It can be concluded that S690QL1 HSS welded joints can generally be subjected to PWHT, while adhering to the limits of the material and process. In the authors’ shared opinion, it is advisable to use the PWHT Cycle C (max. 550 °C) with 93% RS reduction, while mechanical properties retain high values.

Analysis of residual stress relief for Ti62A alloy welded joints by post weld heat treatment considering creep effect

In this paper, the Arrhenius-type constitutive equation based on strain compensation was developed, and the constants of the constitutive equation were determined by linear fitting to construct the material models of Ti62A alloy. Meanwhile, the creep parameters of Ti62A alloy at high temperature were corrected by existing experiments, and the Norton creep model during post weld heat treatment (PWHT) was established. The sequential coupling finite element method was used to calculate the residual stress distribution in the welding and PWHT processes of Ti62A alloy plates. The effects of PWHT parameters on the residual stress relief of welded joints were revealed, such as creep, heating rate, and heat treatment temperature. The results reveal that the creep has an important influence on residual stress relief during PWHT. Compared with longitudinal residual stress, the effects of heating rate and heat treatment temperature on transverse residual stress are more significant. A lower heating rate or higher heat treatment temperature will be beneficial for releasing residual stress. The results of this paper will contribute to a better understanding of PWHT mechanisms and provide a good theoretical guidance for optimizing process parameters.

NUMERICAL ANALYSIS OF STRESS AND STRAIN STATE IN MEMBRANE WALLS WELD JOINTS PERFORMED BY SUBMERGED ARC WELDING

The article presents investigation on stress and strain state in weld joints of boiler membrane wall by performing numerical analysis (finite element method). The main purpose was to create 3D model which will correspond to real membrane wall geometry under consideration, which will allow to perform strength simulation of numerical models considering variable parameters depending on the temperature. The model was fragment of boiler membrane wall made of X10CrMoVNb9-1 pipe and 10CrMo9-10 flat bar welded with submerged arc method. The research included the assumption of boundary conditions such as temperature cycles, welding method, type of mounting and base materials or heat treatment cycle. Three simulations have been performed depended on base material and temperature cycle adopted. As a result of the simulations, the distribution of temperature, displacement and stress in analyzed cases were obtained. The numerical simulation in dissimilar welded joints X10CrMoVNb9-1 pipe and 10CrMo9-10 flat bar heat treated afterwards, showed that the differences in linear expansion coefficients favour the development of cracks in the welds caused by increased level of stress. In parallel materials used for boiler membrane walls are the reason for difficulties in determine the proper technology of welding, preheating temperature and post-weld heat treatment parameters. Simulations indicated that the state of stress in weld joint is dependent on type of parameters adopted, and in closest scenario to real conditions, simulation showed that post-weld heat treatment had no positive effect on the stress state caused by discrepancy in linear expansion coefficients of both base materials.

Influence of PWHT Parameters on the Mechanical Properties and Microstructural Behavior of Multi-Pass GTAW Joints of P92 Steel.

The 9% Cr steels were developed for ultra-supercritical (USC) power plants to meet the requirements of high operating temperature and pressure. These steels are produced to operate at high temperatures where impact toughness is not a concern; however, it becomes important for the welded joints to have good impact toughness at room temperature for manufacturing. The present work investigates the effect of the post-weld heat treatment (PWHT) parameters, i.e., temperature and time, on the impact toughness of multi-pass gas tungsten arc welded (GTAW) joints of ferritic/martensitic grade P92 steel. The microstructural evolution in welded joints given varying post-weld temperatures and times was studied. The lath martensitic structure of the weld metal for the as-welded joints resulted in high hardness and low impact toughness. The weld fusion zone toughness was 12 J, which was lower than the minimum specified values of 41 J (ASME standards) and 47 J (EN ISO 3580:2017). The PWHT temperature and time were found to have a significant effect on the impact toughness of the weld metal. A drastic increase in the impact toughness of the weld metal was noticed, which was attributed to lath break-up, reduction in dislocation density and reduction in solid solution hardening. The maximum impact toughness of 124 J was measured for PWHT temperature and time of 760 °C and 120 min, respectively. The effect of PWHT parameters on tensile strength was also investigated, and test results showed that the joint was safe for USC boiler application as it failed from the region of the P92 base metal. The variation in microstructural evolution along the weldments resulted in hardness variation. PWHT led to homogeneity in microstructure and, ultimately, reduction in hardness value. According to the study, the optimum temperature and time for PWHT of a GTAW joint of P92 steel were found to be 760 °C and 120 min, respectively.

Enhancement of fatigue resistance by direct aging treatment in electron beam welded Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy joint

In most cases, welding processes promote the application of structural materials at the expense of strength and ductility. Post-weld treatment is proposed to regain mechanical properties of weldment, which necessitates that microstructural and the associated mechanical behavior evolutions being clearly understood. In this study, post-weld heat treatment was conducted to enhance the mechanical properties of the electron beam welded Ti–5Al–2Sn–2Zr–4Mo–4Cr alloy joint. Microstructural evolutions and monotonic mechanical properties were characterized to optimize the post-weld heat treatment parameters. It was found that direct aging at 630 °C for 2 h can upraise the strength and ductility of the joint by ∼31% and ∼511% respectively. Metastable needle-shaped martensite α′ within rapidly solidified fusion zone had been completely decomposed, and thin recrystallized α lamella precipitated in the prior β phase without forming consecutive coarse grain boundary α after above direct aging treatment. Such microstructural characteristics enable the direct-aged joint to exhibit a higher fatigue strength from high to very high cycle region than the as-welded joint. Moreover, the fatigue crack nucleation resistance was enhanced significantly through direct aged treatment.

Numerical and experimental investigations on the temperature field in local post weld heat treatment of 9 % Cr heat resistant steel welded pipes

Local post weld heat treatment (PWHT) is usually employed in the field fabrication of large-sized 9% Cr heat resistant steel welded components, such as power plant boilers. Temperature field in local PWHT plays critical roles in both achieving PWHT purposes and avoiding detrimental effects of local heating. The objective of this research is to quantify the effects of local PWHT parameters and pipe dimensions on the temperature field in local PWHT of 9% Cr heat resistant steel pipes and finding the optimal process window to engineer desired weld properties. Finite element (FE) models were developed to simulate the temperature field of local PWHT and carefully verified by eight experiments using four 9% Cr heat resistant steel pipes with typical dimensions employed in ultra-supercritical (USC) boilers. The results show that the through-thickness temperature gradient is severely aggravated with the increase of pipe diameter and wall thickness, which will lead to inadequate tempering in the weld metal close to the inside surface of the pipe. To enlarge heated band (HB) width is an efficient way to mitigate the through-thickness temperature gradient, and the axial temperature gradient can be effectively relieved by augmenting gradient control band (GCB) width. The through-thickness temperature gradient is the major factor in implementing successful local PWHT for 9% Cr heat resistant steel pipes. A much smaller process window is found in 9% Cr heat resistant steel pipes due to their higher PWHT temperatures and narrower range of permissible PWHT temperatures.

Double Pulse Resistance Spot Welding of Dual Phase Steel: Parametric Study on Microstructure, Failure Mode and Low Dynamic Tensile Shear Properties.

Resistance spot welding (RSW) of dual phase (DP) steels is a challenging task due to formation of brittle martensitic structure in the fusion zone (FZ), resulting in a low energy capacity of the joint during high-rate loading. In the present study, in situ postweld heat treatment (PWHT) was carried out by employing a double pulse welding scheme with the aim of improving the mechanical performance of DP590 steel resistance spot weld joint. Taguchi method was used to optimize in situ PWHT parameters to obtain maximum peak load and failure energy. Experiments were designed based on orthogonal array (OA) L16. Mechanical performance was evaluated in terms of peak load and failure energy after performing low dynamic tensile shear (TS) test. Microstructural characterization was carried out using a scanning electron microscope (SEM). The results show that improvements of 17 and 86% in peak load and failure energy, respectively, were achieved in double-pulse welding (DPW) at optimum conditions compared to traditional single-pulse welding (SPW). The improvement in mechanical performance resulted from (i) enlargement of the FZ and (ii) improved weld toughness due to tempering of martensite in the FZ and subcritical heat affected zone (SCHAZ). These factors are influenced by heat input, which in turn depends upon in situ PWHT parameters.

Effect of post-weld heat treatment on the residual stress and deformation of 20/0Cr18Ni9 dissimilar metal welded joint by experiments and simulations

It is known that some problems commonly arise when welding dissimilar metals, especially because it is more difficult to join dissimilar metals than similar metals. Therefore, to join 20/0Cr18Ni9 dissimilar plate with good quality, this paper based on the finite element simulation software Simufact Welding, the residual stress field and deformation results for 6-mm-thick 20/0Cr18Ni9 plates were examined by combining numerical simulation with experimental verification and performing an orthogonal experiment of post-weld heat treatment parameters. The experimental results show that the residual stress of each model is significantly reduced, the reduction of lateral residual stress is greater than that of longitudinal residual stress, the stress reduction of the 20 steel side is significantly larger than that of the 0Cr18Ni9 side, but the deformation of each model was small after heat treatment. It is found that the heat treatment temperature has the greatest effect on the reduction of residual stress and deformation, and the reduction of residual stress will also be affected by the plasticity of the material. Moreover, the material of the weld should be selected as far as possible from the properties of the base metal.

Three-dimensional finite element modelling of welding residual stresses of medium carbon steel pipes with consideration of solid-state austenite-martensite transformation and post-weld heat treatment

In the present work, three-dimensional finite element modelling is presented to simulate welding of the medium carbon steel pipes by considering both the solid-state austenite-martensite transformation and the post-weld heat treatment. Thermo-elasto-plastic and metallurgical analyses are carried out by developing two user-defined subroutines: one for applying the heat flux and the another one for considering phase transformation effects on welding residual stresses. The applied heat flux is simulated by a double ellipsoid model. Furthermore, the effects of volumetric change due to the solid-state austenite-martensite transformation are taken into account. The results obtained have revealed that volumetric change owing to the solid-state austenite-martensite transformation has a significant effect on the magnitude and distribution of welding residual stresses. The main contribution of the present work is providing helpful knowledge about welding residual stresses evolution after and before the post-weld heat treatment by considering the solid-state austenite-martensite transformation. In addition to reference to the time–temperature–transformation diagram, this study can result in safe selection of post-weld heat treatment parameters, which not only prevents sensitization to stress corrosion cracking and intergranular corrosion but also provides enough and more importantly controlled relaxation of welding residual stresses.

Analysis of heat-affected zone microstructures of steel P92 after welding and after post-weld heat treatment

Modern thermal power plant operating on fossil fuels has to be highly efficient and should emit low levels of CO2. One of possible ways to fulfil these requirements is to increase thermal power plant peak service temperature. P92 steel enables service temperature of up to 650 °C. It is stronger, more resistant to creep and enables higher service temperature than P91. During welding of steam boiler components made of P92, it is important to consider proper preheating, welding and post-weld heat treatment parameters in order to avoid cracks and diminish sensitivity to creep in service. The research focused on analysis of simulated heat-affected zone (HAZ) microstructures and distribution of carbides. The FG HAZ (fine-grain heat-affected zone) (Tmax is 950 °C) is the most problematic when it comes to occurrence of type IV cracks, as in this zone, the average representation of carbides on PAGB is 72%, while the average representation of carbides on PAGB in the P21 steel is 58%. After the heat treatment, maximum hardness is recorded in the CG HAZ (coarse-grain heat-affected Zone) (Tmax is 1300 °C), where the values reached 248 HV, which was below the maximum allowable value of 250 HV. Other areas of HAZ expressed the values from 218 to 227 HV. Charpy impact test at service temperatures of 650 °C showed that the CG HAZ was the most critical immediately after welding as the energy for crack initiation was 30 J. However, after obligatory post-weld heat treatment, FG HAZ appeared to be more problematic than CG HAZ, so this research showed that the crack initiation energy value increased due to the fine-grain microstructure, yet the crack propagation energy reduced.

Low heat input welding of nickel superalloy GTD-111 with Inconel 625 filler metal

Abstract GTD-111 precipitation-strengthened nickel-based superalloy is widely used in blades of gas turbine engines which operate at high temperature and in a hot localized corrosion atmosphere. After long-term exposure to high temperature, γ' precipitate is known to exhibit catastrophic changes in size and distribution which cause deterioration of its properties and failure of the component. In this study, a damaged blade removed froma land-based gas turbine generator was subjected to nonpre-heat-treated GTAW and laser welding repair with various welding powers in the range of 135 to 295 J × mm−1, followed by post-weld heat treatment (PWHT) at 1473 K for 7200 s and strain aging at 1118 K for 86 400 s. Results show no significant relationship between welding powers, size and area fraction of the γ' precipitate in the fcc γ matrix in both GTAW and laser-welded specimens. The final γ' precipitate size and distribution depend mainly on PWHT parameters as γ' precipitates in all GTAW and laser welded specimens showed similar size and area fraction independently of the heat input from welding. Unmixed zones are observed in all laser welding specimens which may cause preferential weld corrosion during service. Microcrack occurrence due to welding and PWHT processes is also discussed.

Microstructure Characterization of a Heterogeneous Weld for Welded Rotors

The paper deals with microstructure characterization of a full-scale X14CrMoVNbN 10 1/ 27NiCrMoV 15-6 heterogeneous weld intended for IP/LP welded rotors. The welded rotors are being developed for modern turbines of coal fired power plants operating above 570 °C. The full–scale weld has been shown to be of good internal quality. Hardness surveys revealed the effects of post weld heat treatment parameters on weld metals and parent steels. Microstructure and precipitation of minor phases in parent materials, heat affected zones and weld metals in the state after the final stress relief annealing have been studied.

Application of Response Surface Methodology for Modeling of Postweld Heat Treatment Process in a Pressure Vessel Steel ASTM A516 Grade 70.

This research studied the application of the response surface methodology (RSM) and central composite design (CCD) experiment in mathematical model and optimizes postweld heat treatment (PWHT). The material of study is a pressure vessel steel ASTM A516 grade 70 that is used for gas metal arc welding. PWHT parameters examined in this study included PWHT temperatures and time. The resulting materials were examined using CCD experiment and the RSM to determine the resulting material tensile strength test, observed with optical microscopy and scanning electron microscopy. The experimental results show that using a full quadratic model with the proposed mathematical model is Y TS = −285.521 + 15.706X 1 + 2.514X 2 − 0.004X 1 2 − 0.001X 2 2 − 0.029X 1 X 2. Tensile strength parameters of PWHT were optimized PWHT time of 5.00 hr and PWHT temperature of 645.75°C. The results show that the PWHT time is the dominant mechanism used to modify the tensile strength compared to the PWHT temperatures. This phenomenon could be explained by the fact that pearlite can contribute to higher tensile strength. Pearlite has an intensity, which results in increased material tensile strength. The research described here can be used as material data on PWHT parameters for an ASTM A516 grade 70 weld.

Evaluation of post-weld heat treatment behavior in modified 9Cr–1Mo steel weldment by magnetic Barkhausen emission

The butt joint of two sight tubes of modified 9Cr–1Mo steel is welded by TIG technique. Subsequently, the post-weld heat treatment (PWHT) of the tubes has been carried out at 650, 700 and 750 °C temperatures for 3 h. Magnetic Barkhausen emission (MBE) measurements are performed in fusion zone, heat affected zone (HAZ) and base metal region of as-welded and all the post-weld heat treated samples. In each weldment, the variation of the MBE signal emanated from fusion zone, HAZ and base metal has been examined. It is found that the RMS voltage of MBE signal increases with PWHT temperature. The conversion of retained austenite to alpha ferrite during PWHT makes the fusion region as a softer zone in the weldment. The variation of magnetic parameters with different PWHT is correlated with hardness and microstructures. This study can be used as an effective tool in evaluation of PWHT parameters in modified 9Cr–1Mo weld joint.

Study on the Effect of Post Weld Heat Treatment Parameters on the Relaxation of Welding Residual Stresses in Electron Beam Welded P91 Steel Plates

Residual stresses are created by localised heating effects that occur during the welding process. Post weld heat treatment (PWHT) is the most convenient method for stress relief of welds. But PWHT cannot completely eliminate the residual stresses. So, it is essential to determine the influence of PWHT parameters like holding temperature and time on the stress relaxation for optimising the process. The selected material is modified 9Cr-1Mo (Grade 91) steel in the form of plates welded together using a high intensity electron beam. To facilitate the study, a numerical thermo-elastic-plastic model has been developed to simulate the welding of the plates. As P91 steels undergo phase transformations, the corresponding volumetric change and transformation plasticity are taken into consideration during the analysis and welding residual stresses are predicted. PWHT is implemented using Norton creep law and the residual stresses after relaxation are determined. The developed model and the predictions are validated using neutron diffraction measurements on as welded and post weld heat treated plates. A good agreement has been achieved between the measurements and predictions. The validated model has been used to study the effect of variation of heat treatment parameters like holding temperature and time on the relaxation of welding stresses.

Application of Full Factorial Design for Post Weld Heat Treatment Parameters on Duplex Stainless Steel UNS31803

In this research, the post weld heat treatment (PWHT) of duplex stainless steel (DSS) was study. The PWHT process can be affected by differing parameters. The specimen was duplex stainless steel UNS31803 grade sheet of 10 mm thickness. The PWHT parameters were analyzed by application of full factorial design. The factors used in this study were PWHT temperature of 650, 750, and 850๐C with PWA time of 1, 2, 4 and 8 hours. The welded specimens were tested with micro vickers hardness and ferrite content testing according to ASTM E3-11 code. The result showed that both of PWHT temperature and PWHT time interaction on hardness and ferrite content for 95% confidential (P value < 0.05). The factor in most effect of hardness was the PWHT temperature of 850๐C and PWHT time for 4 hour at the hardness of 277.73 HV. The ferrite was the most ferrite content for 77.39% resulted in corrosion resistance due to suitable of PWHT temperature 750๐C and PWHT time for 8 hour. Finally, form PWHT process with the information was used choosing the appropriate for PWHT parameters to duplex stainless steel welds.