Residual Stress Behavior Research Articles

An Assessment of the Residual Stress of Pipelines Subjected to Localized Large Deformations

Subsea pipelines subjected to impacts are prone to generating significant deformations and residual stresses, which could reduce their structural integrity and increase the risk of failure. This paper introduces analytical and numerical frameworks aimed at predicting residual stress behavior induced by subsea pipeline impacts. An empirical formula to regulate residual stress levels in extensively deformed submarine pipelines is derived through a parameter-fitting method. This formula enables the swift and accurate computation of the residual stress magnitudes in such pipelines. Abaqus is employed to simulate the residual stresses in large-deformation submarine pipelines. The results of the finite element analysis are validated through experimental work. A comprehensive database is constructed via the finite element method to fit an empirical formula for residual stresses in large-deformation submarine pipelines. The empirical formula places particular emphasis on the influence of the diameter-to-thickness ratio and dent depth on the residual stresses. It is crucial for pipeline design and maintenance.

Exploring the Impact of Heat Treatment on Residual Stress, Microstructure, and Mechanical Behavior of Laser Powder Bed Fusion Additively Manufactured Ti-6Al-2Sn-4Zr-2Mo Alloy

In the field of additive manufacturing (AM), a promising alloy that is gaining attention is the near-α Ti-6Al-2Sn-4Zr-2Mo (Ti6242) alloy. This alloy is known for its remarkable resistance to creep and corrosion at elevated temperatures. However, the production of Ti6242 components via Laser-based AM technologies faced with several challenges, such as the formation of residual stress in the as-built state that originates from the nature of these processes. Therefore, this study has a dual objective: first, to evaluate the microstructure and residual stresses in the as-built Ti6242 produced through laser powder bed fusion. Secondly, to investigate the impact of a promising post heat treatment on mitigating residual stresses, inducing alterations in the microhardness of the Ti6242 alloy and its ductility, phase transformations and microstructure evolution. The as-built specimen exhibited a significant residual stress of 1357 MPa, which was caused by the pronounced temperature gradients experienced during the fabrication process. It is interesting to note that this promising post heat treatment was highly effective in eliminating 99% of the residual stress. After heat treatment, the amount of α' present in the as-built specimen decreased. This resulted in the activation of diffusion of elements such as molybdenum, causing a proportion of the α' to decompose into the more ductile α+β structure. Additionally, it is revealed that the microstructural changes and relieved stresses from the heat treatment process caused a lower microhardness and a higher ductility under compressive loading, as the elongation and toughness reached 20.5% and 23.255 kJ/mm3 in the heat-treated samples, respectively. The outcomes of this work facilitate the use of this alloy in the production of complex shape components through laser-based AM technologies.

Shot peening effects on Cr-Mo-V steel: a comprehensive study of microstructure, surface roughness, residual stress, and mechanical behavior

This study presents a comprehensive study of the microstructure, mechanical characteristics, and surface roughness of Cr-Mo-V low alloy steels and a detailed investigation of the overall impact of shot peening (SP). The microstructure was examined using the optical and scanning electron microscope, showing a significant grain size decrease after shot peening. Evaluations of mechanical characteristics, such as microhardness and tensile strength, showed a noteworthy rise, suggesting enhanced material strength. Studies using fragmentography shed more light on changed fracture tendencies. X-ray diffraction technique (XRD) was used to measure residual stress distribution, and the outcomes displayed an increase after SP, which suggests that internal stresses were created. Surface roughness measurements also showed a noticeable decline, indicating better surface quality. The transformational effects of shot peening on Cr-Mo-V low alloy steels were highlighted by comparative investigations with base metals, providing insights into enhancing material performance for various engineering applications.

Effect of shot peening on surface characteristics and high-temperature corrosion behaviour of super 13Cr martensitic stainless steel

Super 13Cr, as an economy stainless steel (SS) for oil country tubular goods, needs stable corrosion resistance in high-pressure and high-temperature (HPHT) downhole medium. Severe plastic deformation (SPD) are the surface modification technology to improve mechanical properties, fatigue behavior and corrosion resistance of metals, and shot peening (SP) has been the most widely used SPD process. However, there are quite limited studies about the microsutructure evolution, residual stress, and high-temperature corrosion behavior of SP-treated martensitic SS. In this study, super 13Cr martensitic SS was treated by SP with various air pressures and nozzle speeds. The surface characteristics and high-temperature corrosion behaviour in 3.17 mol/L K2HPO4 solution were investigated through finite element model analysis, characterization of residual stress and microstructure, as well as electrochemical and stress corrosion cracking (SCC) tests at 160 °C and 10 MPa. The results showed that SP-treated super 13Cr could generate high-level compressive residual stress and SPD microstucture, including nano-sized equiaxed grains, gradient lamellar structure and fragmented carbides. Increasing air pressure contributed to achieve uniform nanocrystalline, but tended to generate high dislocation density and surface defects. The improving effect of SP treatment at low air pressure of 0.15 MPa on passivation ability was limited, and high air pressure adversely impacted corrosion resistance. SP-treated specimens showed high SCC susceptibility, due to the introduction of more surface defects, high angle grain boundaries, and dislocations.

Multiscale simulation combined with experimental investigation on residual stress and microstructure of TC6 titanium alloy treated by laser shock peening

The evolution behavior of residual stress and microstructure of TC6 titanium alloy under laser shock peening (LSP) were investigated using finite element (FE) and molecular dynamics (MD) simulations combined with experiments. The propagation process of laser-induced stress wave and plastic deformation behavior of TC6 titanium alloy model were studied using FE software with ABAQUS. The FE simulation results showed that increasing laser energy and impact time could increase the amplitude of compressive residual stress (CRS) to a certain extent, while a higher overlapping rate improved the CRS uniformity. The experimental results of residual stress testing based on XRD technology were consistent with the FE simulation results. Based on the piston shock method, the microstructural evolution process of α phase of titanium alloy under different shock velocities was simulated using MD software with LAMMPS. Laser shock wave promoted the transformation of hexagonal close-packed (HCP) structure to body-centered cubic (BCC) and face-centered cubic (FCC) structures in titanium alloy, and the generated dislocation density increased with increasing shock velocity. The severe plastic deformation caused by laser shock wave induced the formation of mechanical twin, subgrain and stacking fault, which was consistent with the (transmission electron microscope) TEM characterization results.

Effect of Thickness on the Residual Stress Profile of an Aluminum Cold Spray Coating by Finite Element Analysis

This research investigates the influence of thickness on residual stress profiles in aluminum cold spray coatings using finite element analysis (FEA). Residual stress is a critical factor that impacts coating adhesion, fatigue life, and susceptibility to delamination in thermal spray processes. Despite its acknowledged importance, predictive analysis of these stresses on a layer-by-layer basis remains relatively unexplored. This study introduces an innovative numerical methodology to analyze the progression of residual stresses across various deposition efficiencies (10%, 40%, 60%, and 100%) and layer thicknesses, thereby enhancing predictive accuracy for cold spray coatings. The findings demonstrate that the number of deposited layers significantly affects residual stress profiles in both coatings and the substrate, with compressive residual stress predominating in the coatings and deeper tensile stress predominating in the substrate. Residual stress behavior near the last deposited layer aligns with the expected peening effect. Discrepancies in substrate stress distributions may arise from variations in deposition parameters and unconsidered temperature effects. While the model generally aligns with theoretical and some empirical data, observed discrepancies underscore the need for further validation. This study lays the groundwork for informed decision-making for cold spray processes by providing insights into stress management, thereby contributing to enhancing coating integrity and performance.

Effect of annealing process on microstructure, residual stress, and fatigue behaviour of AISI 2205 duplex stainless steel

ABSTRACT This study investigated the microstructure, residual stress, and fatigue behavior of duplex stainless steels that have been annealed with different annealing processes. A cold-rolled AISI 2205 Duplex Stainless Steel (DSS) sample was annealed in three ways for this purpose. In modes 1 and 2, samples were annealed at 500°C for 6 and 8 hours, respectively. The sample was annealed for 6 hours at 950°C for mode 3.The Optical Microscopy (OM) technique was used to determine the crystallographic texture and microstructural characteristics. An X-ray Diffraction (XRD) analysis was used to determine the residual stresses in austenite and ferrite phases on pre- and post-heat-treated samples. The Scanning Electron Microscope (SEM) technique was utilized to assess fatigue cracks. The results showed that the texture microstructure of the specimens using mode 1 and 2 were remained; the grain had a smaller fragmentation. The elongation grains of the specimen after mode 3 were smaller, relatively spheroidal, and more homogeneous. There was a reduction in residual stress after mode 3 annealing process. The fatigue strength of the specimens that under applied this process was 11.1% higher than that of specimens in the as-received state.

Multiscale residual stress and mechanical behavior analysis in machining of Ti-6Al-4V alloy with advanced microscopic characterization

Machining of polycrystalline metal materials results in metallurgical modifications in the machined surface, and it can introduce multiscale residual stresses (macroscale and microscale residual stress), which may be detrimental to the mechanical properties thereby interfering with the service performance of machined parts. However, most of the current studies only focus on the macroscale residual stress, the microscale residual stresses have always been neglected since the limitations of the commonly used techniques for residual stress measurement in machined surfaces. In this study, the recently developed Focused Ion Beam-digital image correlation (FIB-DIC) ring core method was employed to evaluate the time-resolved strain relaxation and multiscale residual stress of the machined surface under different cutting conditions. The quantitative evaluation of residual stress and microstructural effects on hardness of the machined surface was conducted by combining with FIB incremental milling and nanoindentation technique. It has been observed that although the global tensile strain relaxation was captured in the ring-core region, local microscale compressive strain relaxation also occurred. The hardness of the machined surface was determined by the combined effects of microstructure and residual stress induced by machining. Specifically, the grain refinement and compressive residual stress contributed to hardening, while tensile residual stress resulted in softening of the machined surface. Furthermore, it was also observed the hardening/softening effects were enhanced with increasing intensity of tension and compression.

Investigation of Residual Stress Behavior of TiN Coating Film on Automotive Spring Steel using Multi-arc PVD Method

Investigation of Residual Stress Behavior of TiN Coating Film on Automotive Spring Steel using Multi-arc PVD Method

Synergistic integration of laser shock peening and heat treatment for refined microstructure and enhanced mechanical properties in additively manufactured 17–4PH stainless steel

This study explores the combined effects of laser shock peening (LSP) and heat treatment (HT) on the microstructure, residual stress, and mechanical behaviour of selective laser-melted 17–4 precipitation-hardened (PH) stainless steel. Subsequently, laser shock peening (LSP) was performed on both as-printed (AP) and heat-treated (HT) sample surfaces, and their microstructure, residual stress, and mechanical behaviour were evaluated. The severe plastic deformation (SPD) resulted in significant compressive residual stresses (CRS) in the surface layer of the AP+LSP (-879 MPa) and AP+HT+LSP (-850 MPa) samples. Laser peening caused dislocation accumulation and micro-level grain refinement in the sample's deformed layers, improving its mechanical properties. The AP+HT+LSP sample shows significant improvements over the as-printed (AP) sample. The fraction of high-angle grain boundaries (HAGBs) and high misorientation angles were higher in the AP+HT+LSP sample, and its effect is revealed in the microhardness data. The collective contribution of precipitation strengthening, Hall-Petch, CRS, dislocation strengthening, and increased fraction of HAGBs is observed in mechanical and microstructural aspects of laser shock peened specimens.

Assessment of Residual Stress Behavior and Material Properties in Steels Produced via Oxynitrocarburized Metal Injection Molding

Assessment of Residual Stress Behavior and Material Properties in Steels Produced via Oxynitrocarburized Metal Injection Molding

Solidification Track Morphology, Residual Stress Behavior, and Microstructure Evolution Mechanism of FGH96-R Nickel-Based Superalloys during Laser Powder Bed Fusion Process

Solidification Track Morphology, Residual Stress Behavior, and Microstructure Evolution Mechanism of FGH96-R Nickel-Based Superalloys during Laser Powder Bed Fusion Process

Effect of ingredients proportions on mechanical properties in laser-coated WC-blend welds

Abstract In this study, we investigated ceramic-matrix composite coatings created by laser cladding on 45 steel using tungsten carbide (WC) powder with varying weight percentages of Co or Ni additives. Our analysis focused on the influence of Co additives in WC powders on the key properties of the coatings, including the microstructural evolution, hardness, wear, and residual stress behaviors. High residual stresses led to significant cracking in coatings comprising 100% WC. The addition of Co at a concentration of 20% to WC reduces the cracking activity. The microhardness of the coating exceeded that of the substrate by a factor of more than five. The microstructural evolution revealed a typical intergranular fracture in the molten zone, with cracks propagating through the interior of the unmelted WC at 100% WC. In addition, by adding Ni alloys, the composite coatings were extended to three mixtures: WC-Co, WC-Ni, and WC-Co-Ni. The relationship between the three-component mixtures and wear volume of the laser cladding was established, and the ratios of the three-component mixtures were optimized. A reduced quadratic model for three-component mixtures, which provided a better mixture ratio pattern, showed an excellent fit. Based on the experimental results, the developed three-component mixture with better mixture ratios can enhance anti-wear behavior. A satisfactory agreement was obtained between the predicted and experimental values of the wear volume of the laser-coated welds. Overall, our study accomplishes the optimization of the mixture ratio of the three components, which ensured a reduction in the wear of the welds, thereby improving the performance of laser-coated welds.

Tensile mechanical behavior and failure mechanism of 2.5D woven fabric reinforced aluminum matrix composites involving residual stress

The tensile behavior of two and a half-dimensional (2.5D) woven fabric reinforced Al matrix composites involving residual stress was investigated experimentally and numerically. The residual stress and subsequent tensile behavior of the composites were predicted by multiscale finite element modeling. And the correctness of numerical simulation is verified by residual stress, tensile curve, surface strain diagram and fracture morphology. The results show that the inhomogeneous residual stress leads to the damage of the matrix and interface in the interweaving area of yarns. During the tensile process, the surface strain exhibits an obvious periodic distribution characteristic, which is related to the arrangement of yarns. With the increase of tensile strain, local matrix and interface damage accumulate and expand leading to the weft yarn cracking, matrix failure and interface debonding successively. The abrupt fracture of the composite can be attributed to the axial fracture of warp yarn, which exhibits obvious fiber fracture and pull-out characteristic.

Probing the temperature field and residual stress transformation in multi-track, multi-layered system

A three-dimensional sequential coupled thermo-mechanical modelling is performed for multi-track, multi-layer deposition of Nickel-based superalloy, namely IN625; through laser powder bed fusion (LPBF) technique for real-time monitoring of the thermal response, cooling characteristics and in-process transformation in residual stress in successively built height. The maximum temperature of ∼1100 K is estimated at the top section, whereas ∼810 K is at the middle section during solidification. This spatial transition in temperature distribution over the same built structure is caused by differences in local cooling rates. The steel substrate/backing plate that was utilised demonstrated a heat sink effect and contributed to altering the cooling properties and residual stress behaviour in the lower portion of the fabricated built structure. The conduction mode of heat transfer is found to be effective at the bottom section, while the propensity of convective mode is enhanced upon increasing the built height. Cooling rate is highly influenced by the temperature gradient, hence similar pattern is achieved for both solidification parameters during the deposition process. Tensile longitudinal (S11∼303 MPa) and transverse (S22∼455 MPa) residual stress is obtained at the location of 4.5 mm from the bottom side, compensated by compressive stress of ∼180 MPa, on the top and bottom side to maintain structural equilibrium. Reversal of stress field from tensile to compressive and vice-versa couldn’t happen at built (IN625)/substrate (Steel) interface probably due to insignificant difference in coefficient of thermal expansion, i.e., 10 – 12 × 10−6 /K for both alloys.

Surface Residual Stress and Friction Wear Behavior of Vermicular Graphite Cast Iron after Laser Remelting

Surface Residual Stress and Friction Wear Behavior of Vermicular Graphite Cast Iron after Laser Remelting

Process parameters for three-dimensional specimens made of Ti6Al4V materials using additive manufacturing: A review

The Ti6Al4V alloy is highly mechanical, corrosion-resistant, low-specific weight, and biocompatible. Several high-performance applications are ideal for technical uses in the auto, aerospace, and medical sectors. The recent process parameters for Ti6Al4V, manufactured using additive manufacturing methods, are reviewed in this article for the past 20 years. It is possible to link processing parameters with fundamental information. This review finds that the process parameters in additive manufacturing are laser power, scanning speed, layer thickness, and hatch distance. In addition, this reviewed the presence of processes in the additive manufacturing of Ti6Al4V components and their impact on mechanical performance and microstructure analysis. In the additive manufacturing process, the reviewed parameter is the additive manufacturing component that has reduced the defects of microstructural evaluation, residual stress, porosity, compression, and corrosion behaviour of the study.

Corrosion behavior of selective laser melting-manufactured bio-applicable 316L stainless steel in ionized simulated body fluid

Additive manufacturing (AM) is gaining increasing popularity in various fields, including biomedical engineering. Although AM enables fabrication of tailored components with complex geometries, the manufactured parts typically feature several internal issues, such as unpredictable distribution of residual stress and printing defects. However, these issues can be reduced or eliminated by post-processing via thermomechanical treatment. The study investigated the effects of combinations of AM and post-processing by the intensive plastic deformation method of rotary swaging (variable swaging ratios) on microstructures, residual stress, and corrosion behaviors of AISI 316L stainless steel workpieces; the corrosion tests were performed in an ionized simulated body fluid. The results showed that the gradual swaging process favorably refined the grains and homogenized the grain size. The imposed swaging ratio also directly influenced the development of substructure and dislocations density. A high density of dislocations positively affected the corrosion resistance, whereas annihilation of dislocations and formation of subgrains had a negative effect on the corrosion behavior. The first few swaging passes homogenized the distribution of residual stress within the workpiece and acted toward imparting a predominantly compressive stress state, which also favorably influenced the corrosion behavior. Lastly, the presence of the {111}||swaging direction texture fiber (of a high intensity) increased the resistance to pitting corrosion. Overall, the most favorable corrosion behavior was acquired for the AM sample subjected to the swaging ratio of 0.8, exhibiting a strong fiber texture and a high density of dislocations.

Surface integrity after hard turning using specially ground cemented carbides

In order to explore the effects of the tool geometry on the machining process, the aim of this project is to study the surface integrity generated in the 4142 alloy steel after straight turning with customized tungsten carbides cutting tools prepared with customized geometries, verifying their influence on residual stress and roughness behavior. Square cutting inserts were prepared from K10 hardmetal with PVD TiAlN coating varying edge preparation (or form factor) and nose radius. Taguchi methodology was applied for the design of experiments also varying feed rate. Results showed the major influence of feed rate and nose radius, over surface roughness, with the form factor parameter interfering at the components of cutting forces, which could also affect residual stresses and tool-lifetime due to wear.

Effect of ultrasonic rolled material layer on the corrosion fatigue resistance of railway axle EA4T alloy steel

Surface treatment has been validated to improve the fatigue crack resistance of engineering components, while the coupling effect of corrosive atmosphere and external loading is relatively less reported with detailed experimental studies. In this study, gradient structure (GS) axle EA4T alloy steel specimens were prefabricated by using the ultrasonic surface rolling process (USRP), and their corrosion fatigue resistances were investigated. First, the optimal USRP parameters were determined via orthogonal tests. After the USRP treatment, the microstructure, surface topography, surface roughness, residual stress, and electrochemical corrosion behavior were measured to characterize the surface under various conditions. The electrochemical tests results indicated that the compressive residual stress (CRS) is an important factor in improving the corrosion resistance of axle steel. Rotating bending fatigue tests in both air atmosphere and corrosion liquid showed that the fatigue and corrosion fatigue performances could be significantly improved with the strengthened layer obtained via the USRP. Factor separation analyses substantiated that the remarkable enhancement of fatigue and corrosion fatigue strengths can be mainly attributed to the CRS introduced by the surface strengthening treatment. Simultaneously, the GS layer and hardened layer exhibited a synergistic effect.