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Various types of solid-state phase transformation (SSPT) occur during the SA508 steel welding process, especially for multi-pass welding. The multiple thermal cycles lead to a more complex microstructure distribution and significantly influence the residual stress distribution. Therefore, to better control the microstructure and residual stress, it is necessary to optimize the process parameters which are closely related to the welding thermal cycles. This study established a thermo-mechanical-metallurgical multi-field coupling model and then validated it using X-ray and neutron diffraction residual stress measurement tests. Furthermore, the influence of welding heat input and preheating temperature on the formation of phase constituents and the ultimate residual stress field were analyzed in detail, concomitantly with a comprehensive discussion on their underlying mechanisms. The results showed that the increase of heat input expanded the domain occupied by the bainite phase, accompanied by the increase of compressive stress region. Moreover, the rise of preheating temperature promoted the bainite phase transformation, thus decreasing the longitudinal compressive stress and the stress gradient. The variation induced by welding parameters was closely related to the welding cooling rates. To obtain a full bainite and low residual stress condition of welded joint, it becomes imperative to exercise control over cooling rates, maintaining them at approximately 1.0 °C/s. • Increase of heat input expands the area of bainite phase and compressive stress. • Increasing preheating temperature magnifies transverse tensile stress. • As Cooling rate increases, bainite content decreases and martensite content increases. • To get welded joints free of martensite, the cooling rate should be below 1 °C/s. [ABSTRACT FROM AUTHOR]

Benefited by its high efficiency and low cost, the narrow gap welding has been widely used in thick wall pressure equipment. Considering the fact that defects in welded joints inevitable, the safety assessments for welding equipment with residual stress are crucial. However, for the thick-wall equipment using narrow-gap welding, the current safety assessment standards specifying the residual stress distribution are not detailed or missing. In this paper, the through-wall residual stress of thick wall girth welds with narrow gap welding is studied. The stress components (bending stress, membrane stress and self-equilibrating stress) at the evaluation point are obtained by stress decomposition. The effects of the heat input, the wall thickness, the radius thickness ratio and the number of welding passes on residual stress are considered, respectively. The results show that the heat input only affects the distribution of bending stress and membrane stress. The axial and hoop bending stresses decrease with the increase of the wall thickness, and the hoop membrane stress is about 0.75 times material yield strength. With the increase of radius thickness ratio, the bending stress decreases while the hoop membrane stress increases. The stress distribution is fluctuating when the number of welding layers is small, which be expressed by trigonometric function. The distribution model of welding residual stress through the wall thickness is proposed. The stress distribution obtained by the proposed prediction model is in good agreement with the finite element calculation results. • >The universal model of residual stress and stress components for girth weld with thick wall was proposed. • The stress components (bending stress, membrane stress and self-equilibrating stress) of the evaluation point are also obtained. • The effects of heat input, wall thickness, radius thickness ratio and number of welding passes on residual stress are considered, respectively. • Heat input only affect the amplitude of bending stress and hoop membrane stress. • The stress on inner surface using narrow gap welding for thick walls is compressive stress. [ABSTRACT FROM AUTHOR]

The measurement of welding residual stress (WRS) is necessary to formulate the stress control strategies, in order to ensure the reliability of engineering structures during their service life. The instrumented indentation technique can detect surface residual stress nondestructively with an acceptable accuracy, making it a desirable option for in-situ applications. However, it is difficult to meet the requirement for stress-free samples, particularly in the case of welded joints with non-uniform mechanical properties. In this work, the impact of stress-free indentation curves on determining WRS is furtherly studied based on the previously proposed indentation energy difference method. The WRS in a mismatched welded plate is measured using single reference method and distributed reference method, respectively. The study suggests that using the single reference method can lead to significant errors in determining the sign and magnitude of WRS in the weld zone. A prediction model combining the continuous spherical indentation (CSI) method and Back Propagation (BP) neural network is proposed to obtain the stress-free indentation curves of local positions nondestructively. And the CSI-BP method is verified through reverse finite element analysis and experiments. • The WRS were measured by indentation energy difference method. • A continuous spherical indentation -BP neural network prediction model was established to estimate the stress-free indentation curves for unknown materials. • A single reference method and two distributed reference methods were compared in the WRS measurement. [ABSTRACT FROM AUTHOR]

The brazed joint has been widely used in the plate-fin structure, and the periodic pressure suffering in operation makes it very important to ensure the fatigue strength. This paper investigates the fatigue crack growth of 316 L brazed joint by experiments and simulations. Firstly, the mechanism of the fatigue crack growth behavior is analyzed via the scanning electron microscope (SEM) and the electron back-scattered diffraction (EBSD) techniques. Then, the virtual crack closure technique (VCCT) is adopted to simulate the fatigue crack propagation by developing a user subroutine. Lastly, the effect of filler metal thickness on strain energy release rate is discussed. Results show that the fatigue crack mainly propagates along the interface of the base metal and filler metal. However, the crack is still located at the filler metal and follows a transgranular fracture mode. In addition, the simulated results by VCCT agree well with the experiment, which demonstrates the feasible application of VCCT for brazed joint fatigue crack simulation. Besides, the strain energy release rate of the brazed joint has an intrinsic different mechanism compared with the base metal and the filler metal, and the strain energy release rate decreases with the filler metal increasing. • The fatigue crack shows a trans-granular fracture mode in the filler metal. • The VCCT is successfully applied to the fatigue crack simulation of brazed joint. • The stain energy release rate of brazed joint shows a different mechanism. [ABSTRACT FROM AUTHOR]

Abstract This paper studied the distribution of weld residual stress in a spiral welded pipeline by finite element method (FEM) and experimental measurements, and the effect of helix angle on residual stress has also been investigated. Both the FEM and experiment results show that the residual stresses in HAZ are larger than those in weld. The error between FEM and experiment results is within 14%, proving that our FEM is correct. There is a peak-shape stress distribution through the weld thickness and the residual stresses in the inner surface are larger than those in the outer surface. Different helix angle has a different equivalent weld length along the hoop and axial directions, which generates different hoop and axial plastic strains, leading to different hoop and axial residual stresses. As the increase of the helix angle, both the radial and hoop residual stresses decrease, while the axial residual stresses increase. As the helix angle increases from 20° to 50°, the hoop stresses in HAZ decrease by 65%, while the axial stresses increase by 120%. The residual stresses are influenced by the pipe dimension (pipe diameter, thickness, weld profile), welding technology (heat input, welding speed) and material grade. When the helix angle is between 40° and 45°, both the hoop and axial residual stresses are reduced to the minimum. The most suitable helix angle is suggested to design around 40°–45°. Graphical abstract Image 1 Highlights • Effect of helix angle on residual stress for oil pipelines is investigated. • HAZ is a weakest zone for X70 steel spiral pipes. • The residual stresses are easily influenced by the pipe dimension and welding technology. • The most suitable helix angle is suggested to design around 40°–45°. [ABSTRACT FROM AUTHOR]

In this study, a wavelength-dependent neutron diffraction method used to measure the residual stress in thick duplex stainless steel (DSS) welded plate was proposed, which was validated by contour method. By choosing appropriate wavelength, the penetration capability of neutron was improved. The neutron with appropriate wavelengths was then applied to investigate the through-thickness volume fraction, macroscopic and phase-specific residual stress in a 55 mm thick DSS welded plate. The results showed that a wavelength at 2.395 Å had more superiorities than the conventionally-used wavelength at 1.593 Å in the measurement of longitudinal and transverse stresses of a thick DSS plate. In general, high tensile stresses were generated in austenite while high compressive stresses were found in ferrite. For elastic mismatch residual stresses, their maximum values in austenite and minimum values in ferrite were located near the mid-thickness region. Reasons for the formation and characteristics of the phase-specific stresses were also discussed. Besides, large tensile macroscopic stresses were found near the surface whilst significant compressive stresses were found to generate in the mid-thickness of weld metal. • A wavelength-dependent neutron diffraction method for measuring stress is developed. • Altering wavelength enhances the penetrability of neutron in duplex stainless steel. • Macroscopic, phase-specific residual stresses and volume fraction are obtained. • High tensile stress is found in austenite while compressive one is found in ferrite. [ABSTRACT FROM AUTHOR]

In this paper, an energy difference method is proposed to estimate biaxial stress components based on indentation technique. The indentation energy is chosen as an analytical parameter, which can be calculated directly from the load-depth curve. The presence of residual stress in a material causes the change of indentation energy. The mapping relationship between uniaxial stress and indentation energy difference was established by finite element analysis. Meanwhile, the Knoop tip was applied since the indentation response varies according to the indenter orientation. Using this feature, a biaxial stress state can be transformed into two equivalent uniaxial stress states by indentation energy conversion. Finally, the biaxial residual stress components can be solved by the energy difference functions of two orthogonal indentations. A portable indentation instrument was developed to implement this approach, which is suitable for in-site measurement. The obtained results show good agreements with the artificial stresses applied by cross-shape sample experiment. • A new methodology is proposed to estimate biaxial stress components based on indentation method. • The Knoop indenter is applied to correlate the stress direction. • A biaxial stress state can be transformed into two equivalent uniaxial stress states by indentation energy conversion. • An indentation testing instrument was developed to validate this approach. • The biaxial stress components can be solved from the load-depth curves, without the need for contact area. [ABSTRACT FROM AUTHOR]

Abstract: 316L type stainless steel is widely used in chemical industries due to its excellent resistance to corrosion. But the welding residual stresses have a great effect on stress corrosion cracking. This paper used finite element method to study the effect of heat sink on residual stress. The effects of contact length and the average heat transfer coefficient on residual stress have been investigated. It is found that the heat sink technology can decrease the residual stress greatly. Compared to the model without heat sink, 20% of the peak longitudinal stress has been reduced. The heat sink decreases the dwell time during cooling from 850 °C to 400 °C, which is helpful to decrease the risk of sensitization of 316L stainless steel. With the contact length increase, the transverse stress is decreased. Further increase of the contact length has no positive effect on reducing the longitudinal stress. With the average heat transfer coefficient increase, the transverse stress is decreased greatly while the longitudinal stress decreases slightly, and some tensile residual stresses have been changed to compressive in some zone. [Copyright &y& Elsevier]

Abstract: Clad plates are widely used in the construction of corrosion resistant equipment. During the repair of clad plates, residual stresses are generated and influence the structure integrity. This paper uses the finite element method (FEM) to predict the residual stresses in a repair weld of a stainless steel clad plate. The effect of repair width on residual stresses has also been investigated by numerical simulation. Due to the material mismatching between clad metal and base metal, a discontinuous stress distribution has been generated across the interface between clad and base metals. The peak residual stress occurs in the heat affected zone (HAZ) of the base metal, because the yield strength of the base metal is larger than that of the clad metal. With an increase in repair width, the residual stresses are decreased. When the repair width is increased to 24 mm, the residual stresses in the weld have been decreased greatly and the peak residual stresses have been reduced to less than the yield strength. Therefore, the recommended repair width should not be less than 24 mm, which provides a reference for optimizing repair welding technology for this stainless steel clad pate. [ABSTRACT FROM AUTHOR]

Local post-weld heat treatment (PWHT) is often used for mitigating welding-induced residual stresses in pressure vessels and piping systems. As large and ultra-large pressure vessels are increasingly used in petrochemical and power generation industries, traditional local PWHT procedures stipulated in Codes and Standards become difficult to implement for some of the ultra-large vessels due to their very large diameter and overall length. In this paper, a new method referred to as primary-secondary heating based local PWHT technique (PS-PWHT) is proposed. Both finite element residual stress modeling and experimental residual stress measurements were performed for both validating the effectiveness of the proposed technique and elucidating the underling mechanisms. The results show that the PS-PWHT method can reduce welding-induced residual stresses in a significant manner, even leading to some level of compressive residual stresses at the vessel weld region. [Display omitted] • A new secondary tensile thermal stress is generated on the inner surface by local PWHT. • The inner surface stress of cylinder does not drop but rises due to the waist deformation. • The secondary heating can mitigate the waist deformation of the weld through anti-deformation. • The method can suppress the risk of stress corrosion cracking from residual stress standpoint. [ABSTRACT FROM AUTHOR]

Abstract: Stainless-steel plate–fin heat exchanger (PFHE) has been used as a high-temperature recuperator in microturbine for its excellent qualities in compact structure, high-temperature and pressure resistance. Plate–fin structure, as the core of PFHE, is fabricated by vacuum brazing. The main component fins and the parting sheets are joined by fusion of a brazing alloy cladded to the surface of parting sheets. Owing to the material mismatching between the filler metal and the base metal, residual stresses can arise and decrease the structure strength greatly. The recuperator serves at high temperature and the creep would happen. The thickness of the filler metal plays an important role in the joint strength. Hence this paper presented a finite element (FE) analysis of the brazed residual stresses and creep for a counterflow stainless-steel plate–fin structure. The effect of the filler metal thickness on residual stress and creep was investigated, which provides a reference for strength design. [Copyright &y& Elsevier]

Larger residual stresses and deformations are inevitably generated during local post-weld heat treatment (PWHT) for ultra-large pressure vessels, which may lead to cracking in weld joint. In this paper, a new control method with reinforced plate was proposed to prevent cracking during local PWHT for ultra-large pressure vessels. And the evolution of stresses and deformation during local PWHT and the reason of cracking were discussed. The results show that bigger inconsistent deformation along axial direction and larger axial stresses in weld toe are the main reason to cause cracking. The hoop, axial and maximum principal stresses in welded joint can be reduced by reinforced plate. And the maximum radial deformation during holding stage of PWHT was decreased by reinforced plate because of the decreased elastic and plastic strain. The maximum radial deformation was decreased by more than 50%. The inconsistent deformation at heating stage can be improved, so the stress concentration in weld toe resulting in cracking could be also improved. This work will provide a good guidance for the manufacture of ultra-large pressure vessels. [Display omitted] • A new control method was proposed to avoid cracking during local PWHT. • The inconsistent deformation along axial direction is main reason to cause cracking. • The stress concentration in weld toe during PWHT were decreased by new control method. • The inconsistent and maximum deformation at holding stage can be improved greatly. • The new control method can reduce the elastic and plastic strain during PWHT. [ABSTRACT FROM AUTHOR]

Local post welding heat treatment (PWHT) is a feasible method to eliminate weld residual stress for ultra-large pressure vessels. This paper is focused on the discussion of weld residual stress and deformation for the typical ultra-large mechanical penetration inserted plate (MPIP) during the local PWHT. The reason why the MPIP subjected to local PWHT causes cracking is clarified. A rigid-flexible coordinated control method is proposed to prevent cracking during local PWHT for the ultra-large pressure vessels. The results show that the inconsistent deformation and greater stress concentration in weld toe are the main reason to result in cracking during PWHT. The axial stresses and radial deformation in the welded joints can be reduced by the rigid-flexible coordinated control method. The axial stress is changed to compressive stress, and the radial deformation is reduced by about 58%. And the inconsistent deformation in welded joints during the heat treatment can be obviously improved, which is of great significance to ensure the safe service for ultra-large pressure vessels. [Display omitted] • The greater stress concentration induced by bend deformation is the main reason of cracking. • A rigid-flexible coordinated method was proposed to avoid cracking during local PWHT. • The axial stress and radial deformation in weld during PWHT were improved by new method. • The inconsistent and maximum deformation at insulation stage can be improved greatly. • The smooth weld can reduce the risk to occur cracking during local PWHT. [ABSTRACT FROM AUTHOR]

The welding residual stresses (WRS) in a cracked head-cylinder joint of a large rectifying tower were studied by finite element method (FEM) and experimental study. The effects of welding layer sequence, cover welding direction and weld reinforcement have been fully studied. The results showed that the stress concentration and plastic strain accumulation caused by unreasonable welding process and structural discontinuity are the main reasons of cracking. Furthermore, the order of welding layers has a significant influence on the distribution of axial stress: the inside and outside alternating welding process is superior to non-alternating welding process. The direction of cover welding markedly influences the hoop stress: the location of maximum stress is related to the welding start-end position. Besides, the removal of weld reinforcement after welding helps to release sub-surface tensile stress and solve the stress concentration problem. • Recommendations regarding welding procedure in large pressure vessels were proposed by FEM and experiment study. • High tensile WRS and large PEEQ at the weld toe directly contributed to the cracking. • The axial stresses can be effectively reduced by alternating welding. • The position of peak stress is related to the cover welding direction. • Removing the weld reinforcement helps to further control WRS. [ABSTRACT FROM AUTHOR]

Strip clad welding is a key manufacturing process of large pressure vessel and repair welding was usually used to repair the defects of strip welded structure, which generates very complex residual stresses and have a great effect on structure integrity. Therefore, in this paper, the residual stress distributions and their evolutions during strip clad welding, post-welding heat treatment (PWHT) and repair welding of a large pressure vessel were investigated. A new strip cladding heat source model considering the magnetic pinch effect was proposed. The predicted welding pool size by the proposed heat source model has a good agreement with the experiment results. And the predicted residual stresses in every stage agree very well with those by indention measurement method. The residual stresses after strip clad welding along the through-thickness direction present tension-compression-tension distribution. The PWHT has little eliminating effect on tensile residual stress on cladding layer, and even worsens the discontinuity stress distributions across the interfaces between the clad metal and base metal. After repair welding, local detrimental tensile residual stresses were generated in the repaired zone. A new heat treatment method based on distinct temperature regulation is proposed, which has a good ability to eliminate the tensile stress of the cladding layer to compressive stress and has a good application in engineering. Image 1 • An improved moving heat source model for strip cladding was proposed. • The simulated temperature and stress field and agree with the experiment very well. • PWHT cannot completely eliminate the cladding residual stress. • The residual stress on bottom surface was affected by the initial stress model. • A new PWHT method based on distinct temperature regulation was proposed. [ABSTRACT FROM AUTHOR]

Due to the limited testing methods and high costs, researches on the evolution law of residual stress in the post-weld heat treatment (PWHT) process of pressure equipment are mainly by numerical simulation, in which the selection of a reasonable and reliable creep constitutive model is crucial to ensure the accuracy of numerical predictions. It is worth noting that the temperature changes and residual stress variation during the heat treatment process result in the following creep characteristics: the creep occurs under different temperatures during the heat treatment processes of heating, holding, and cooling; the creep occurs under different residual stress level where the residual stress varies during the heat treatment stages. Thus, to accurately simulate the stress release behavior during the PWHT process, the proper creep constitutive model must involve the influences of the temperature and the stress state. Meanwhile, current heat treatment simulation usually adopts simplified qualitative approaches, and the creep constitutive models often ignore the physical mechanisms and characteristics of actual creep processes, such as the Norton, the Norton-Bailey, and the Omega models. As a result, the accuracy of heat treatment simulation is limited. In this paper, a new creep constitutive relation under varying temperature and stress is proposed. The hyperbolic-sinusoidal function is used to represent the complete three stages of creep, which compensate the inaccuracy prediction at the first and the third creep stages. Moreover, the Arrhenius function is introduced to characterize the creep response under varying temperature conditions, which enables the prediction of residual stress evolution throughout the entire heating-holding-cooling process of heat treatment. Then, a typical pressure vessel cylindrical circumferential weld is simulated. The stress release during the heat treatment is calculated, and the efficacy of the proposed model is validated through surface residual stress testing. It is found that the creep behavior is a crucial factor in numerical simulation of heat treatment, and the creep constitutive relation can significantly affect the accuracy of heat treatment simulation. The simulation utilizing the hyperbolic-sinusoidal temperature-dependent creep model is much more accurate compared to the classical simulation. The simulation results are much more consistent to the experimental results. Specifically, the traditional model often underestimates the stress state, the residual stress drops abruptly during the heating stage. The residual stress evolution mechanism is simulated using the new model: The majority of residual stress are released during the heating process which primarily relies on the creep strain transformation (contributes up to 85%). The stress state does not change during the holding stage and slight higher at the cooling stage. • A new creep constitutive relation suitable for post weld heat treatment under varying temperature and stress is proposed. • It is found that the creep behavior is a crucial factor in numerical simulation of heat treatment. • The mechanism of residual stress evolution during heat treatment has been summarized. [ABSTRACT FROM AUTHOR]

The support platform is an essential component of a hydrogenation reactor, providing stable support for internal components and ensuring efficient reactions. However, the manufacturing method of overlay welding and complex structure of support platform unavoidably generates welding residual stresses (WRS) and stress concentration, posing a threat to operational reliability. In this paper, the WRS distribution and cracking causes of the support platform of hydrogenation reactor was studied by the finite element method (FEM) combined with experimental research. Four manufacturing processes for the support platform were compared in terms of their residual stresses, and the influence of welding heat input and fillet size on the WRS was discussed. The results indicate that the abrupt increase in residual stresses at the fillet region following the machining of the base layer has enhanced the likelihood of crack occurrence. The cumulative effect of stress concentration resulting from improper welding processes and structural discontinuities, along with the tensile stress during normal operating conditions, renders the surface layers susceptible to cracking during service. The manufacturing process significantly influences the distribution of residual stresses. To obtain a reliable and crack-resistant large-sized hydrogenation reactor support platform, a welding procedure with a certain machining allowance at the support platform location prior to overlay welding should be adopted. The fillet size has a notable effect on the residual stresses at the fillet region of transition layer. Recommended fillet sizes are 15 mm radius for the base layer, 11 mm radius for the transition layer, and 8 mm radius for the surface layer. Additionally, the heat input greatly affects the hoop stresses in the transition layer, in order to avoid the occurrence of cracks, a recommended heat input of approximately 20 kJ/cm is suggested. • Residual stress distribution and crack causes of the support platform were analyzed. • Surface layer fillet is more prone to cracking. • Manufacturing with a machining allowance as the root has optimal stress distribution. • Increasing fillet size significantly reduces residual stress of transition layer. [ABSTRACT FROM AUTHOR]

Stress corrosion cracking (SCC) is the main failure mode of tube-to-tubesheet welded joints in a heat exchanger, and weld residual stress can play an important role in the development of these cracks. Local post welding heat treatment (PWHT) is a feasible method to reduce weld residual stress for tube-to-tubesheet welded joints. In this paper, the residual stress evolution and relaxation mechanisms during local PWHT were discussed in depth. The effects of PWHT temperature and hold time on residual stress were clarified. A compressive stress manufacturing method based on local PWHT was proposed. The results show that the stress concentration at the root of tube-to-tubesheet welded joints is the main reason for the SCC of heat exchangers. The residual stresses in the weld and heated affected zone (HAZ) are significantly reduced during local PWHT. The residual stress relaxation of tube-to-tubesheet welded joints can be attributed to the creep strain development and deformation during local PWHT. The extrusion of the tube and tubesheet at cooling stage results in the generation of compressive stress at the root of tube-to-tubesheet welded joints. PWHT temperature has significant effect on the residual stress in the weld and HAZ in comparison with PWHT hold time. The application of the proposed compressive stress manufacturing method realizes the fabrication of compressive stress at the root of tube-to-tubesheet welded joints, and improves the economic benefit by reducing PWHT hold time. This work will provide a good guidance to reduce the SCC risk of heat exchangers. • The stress concentration at the root of tube-to-tubesheet welded joints was found to be the main reason for SCC. • The residual stress relaxation mechanisms of tube-to-tubesheet welded joints during local PWHT were clarified. • PWHT temperature had significant effect on the residual stress in the weld and HAZ in comparison with PWHT hold time. • The proposed local PWHT method realized the fabrication of compressive stress at the root of tube-to-tubesheet welded joints. [ABSTRACT FROM AUTHOR]

Creep crack growth (CCG) behaviors of 9Cr–1Mo heat resistant steel under different stress states, such as the different initial crack lengths, two/three dimensional stress states, different side groove depths and angles are investigated by the numerical method. The results show that decreasing the initial crack length can increase the specimen life. Affected by the higher stress tri-axiality in the specimen, the side groove specimen life is greater than that the plain CT specimen. Crack front straightness extent increases with the increasing of value of d / B 0 or magnitude of the α. The side groove depth of d / B 0 = 0.1 and side groove angle of α = 80° meet the crack front straightness requirement, and it can be used to predict the CCG rate of the 9Cr–1Mo steel. The CCG rate of the plane strain specimen is greater than that the plane stress specimen for both the same loading condition of initial stress intensity factor and reference stress. On the whole, all the CCG rate data are dropped into the 95% prediction band of fitting curve, demonstrating that the CCG rate of 9Cr–1Mo heat resistant steel can be reasonably calculated by C *. • CCG of the 9Cr–1Mo steel under different stress states is investigated by the FEM. • Decreasing the initial crack length can increase the life of specimen. • Increasing side groove angle of the CT specimen can decrease the life of specimen. • Side groove depth of d/B0 = 0.1/angle of α = 80° can insure crack front straightness. • CCG rate of the 9Cr–1Mo steel can be reasonably predicted by the C*. [ABSTRACT FROM AUTHOR]

Based on the expanding cavity model and energy analysis, an analytical derivation was first conducted to develop a correlation between the increment of elastic and plastic portions of external work and the von Mises stress-strain increment, yielding an incremental indentation energy method (IIEM) to determine the stress-strain relationship from spherical indentation tests (SITs). The IIEM has two potential approaches in determining the proportional limit, one from indentation plastic zone radius r p measurements and the other from trial-and-error. Through an application of digital image correlation on the various zones of ferritic (SA508Gr.3Cl.1) to austenitic stainless steel (316L) dissimilar metal welds (DMWs), it was found that the r p measurements is capable for the two bases, but failed in the other six zones due to the inhomogeneous characteristic of DMWs. In this case, the mean strain development of indentation plastic zone was extensively investigated through systematic finite element analysis to establish an IIEM independent of r p measurements. Solidarity of the IIEM was verified through experiments on the eight representative zones of DMWs, and compared with its previous counterpart (the empirically concluded Kwon method). It was found that the IIEM can restrain errors caused by the compensation effect in reverse predictions, leading to more accurate strength predictions (with a maximum error 9.85%). This study is expected to provide a convenient and reliable approach for predicting the uniaxial tensile properties from SITs, especially when the r p measurement is not applicable. • An incremental indentation energy method (IIEM) was established for tensile property determination. • Applicability of the plastic zone radius measurement on the various zones of DMWs was investigated. • Effectiveness of the IIEM was verified through experiments on DMWs. • Influence of indenter size on prediction accuracy and repeatability was discussed. [ABSTRACT FROM AUTHOR]