Wire Arc Additive Manufacturing Technology Research Articles

Modelling the weld cladding process to predict weld clad position and shape error

Wire arc additive manufacturing (WAAM) is one of the most productive metal additive manufacturing methods. One of its most promising applications holds in the manufacturing of difficult-to-cut materials where production costs can be reduced with minimizing the time of machining and total tool costs. To develop a correct WAAM, technological processes for manufacturing complex-shaped components welding torch path corrections and welding power corrections have to be made especially in critical sections such as corners and sharp edges. A predictive mathematical model of the material cladding during the WAAM process has been developed for the purposes of generating an optimal toolpath of the WAAM clads. This predictive mathematical model is simplified to reflect the important physical phenomena in the weld pool but also to optimize computing time. In this paper, the principle of the mathematical model is described, and its functionality is verified by the welding experiments with five different welding power settings. For the initial calibration of the model parameters single straight-line weld clads with 5 different welding power settings (wire feeds) ranging from 5.0 to 8.6 m/min were investigated. 3D scans of these welded samples are used for the verification. With the calibrated simulation model, it was possible to predict the precise shape with a maximum deviation circa 0.20 mm. The start portions of the weld clads seem more complex having the deviation circa 0.30 mm. These are valuable results as the WAAM technology is generally considered to be reasonably rough.

Comparative study on corrosion property of 2219 aluminum alloy sheet and additively manufactured 2319 aluminum alloy

2319 aluminum alloy parts was prepared by wire arc additive manufacturing technology. The corrosion properties of additively manufactured 2319 aluminum alloy and 2219 aluminum alloy sheets were systematically investigated by electrochemical tests and localized corrosion tests. The results of electrochemical tests showed that the 2219 aluminum alloy sheet has a lower corrosion current density than the additively manufactured 2319 aluminum alloy. Localized corrosion test results indicated that the additively manufactured 2319 aluminum alloy exhibited a higher intergranular corrosion depth and more severe corrosion morphology than the 2219 aluminum alloy sheet. This suggests that the 2219 aluminum alloy sheet has higher corrosion resistance than the additively manufactured 2319 aluminum alloy. The poor corrosion resistance of additively manufactured 2319 aluminum alloy could be attributed to the formation of a coarse continuous Al2Cu phase along the grain boundary. Based on this, heat treatment was used to dissolve the Al2Cu, which can effectively improve the corrosion resistance of additively manufactured 2319 aluminum alloy to the same level as that of the 2219 aluminum alloy sheet.

Enhancing the geometry accuracy and mechanical properties of wire arc additive manufacturing of an Al-5%Mg alloy through longitudinal magnetic field influence

To address the issues of low deposition efficiency, poor geometric accuracy, and high porosity in wire arc additive manufacturing (WAAM) specimens, a longitudinal alternating current (AC) magnetic field-assisted WAAM method was employed. The results showed that the introduction of the longitudinal AC magnetic field significantly enhanced the geometric accuracy of the specimens. After magnetic field assistance, the porosity of the WAAM Al-5%Mg alloy specimens decreased from 0.372 % to 0.016 %. The grain size decreases from 71.95 μm to 56.3 μm, with a notable increase in the proportion of small grains (D < 30 μm) from 27.06 % to 44.57 %. The longitudinal tensile strength increased from 243 MPa to 260 MPa, while the transverse tensile strength increased from 232 MPa to 257.7 MPa. Moreover, the longitudinal and transverse tensile strengths tended to be isotropic. Therefore, the longitudinal AC magnetic field has a significant impact on the performance of AlMg alloy WAAM specimens. This study presents novel strategies and theoretical guidance for enhancing the efficiency and component performance of aluminum alloy WAAM technology.

Study on properties of 304 wire arc additive manufacturing stainless steel TIG welded joints

In this study, 304 stainless steel thin-wall component were obtained by wire arc additive manufacturing (WAAM) as one of the methods of additive manufacturing. In view of the limits that the WAAM technology can not produce large and complex components at one time, TIG welding was chosen during secondary processing to achieve the effectively connection. Weldability, microstructure, texture strength and mechanical properties were particularly investigated when welding along the traveling and building direction. The results show that welding along the traveling direction gained better performance weld joints than building direction including higher tensile and yield strength, greater elongation and lower texture strength. Besides, the grain orientation changed from [001] before welding to [111] after welding in both traveling and building direction.

Effect of Hot Deformation on Microstructure and Porosity of Additively Manufactured 7050 Al Alloy

Wire arc additive manufacturing technology of 7050 aluminum alloy has a broad application prospect in aerospace field. But the lack of comprehensive properties caused by coarse columnar grains and pores becomes an important bottleneck. In this study, hot compression is conducted to simulate forging process to investigate the microstructure improvement of as‐deposited 7050 Al alloy by plastic deformation. The effect of temperature at 390–540 °C and deformation at 20%–60% on the microstructure and porosity is revealed. In the results, only slip deformation occurs at 420 °C and below. Local dynamic recrystallization occurs at columnar grain boundaries at 450 °C. Complete dynamic recrystallization occurs at 480 °C with the average grain size of about 60 μm. The microstructure overburns at 510 °C and above. The η eutectic phases are broken during deformation. The hot deformation accelerates the dissolution of η eutectic phases and the dissolution temperature of nano‐phases is 30 °C lower than solid solution. As the deformation amount increases from 20% to 60%, the deformation gradually extends from interlayer to inner of columnar grain layers. The spherical pores are first compressed to ellipsoid and then further compressed until completely closed. The pores are basically annihilated completely at 60% deformation with porosity of less than 0.1%.

Mechanical behavior of austenitic stainless steels produced by wire arc additive manufacturing

Wire arc additive manufacturing (WAAM) is an innovative technology with the potential to drive the transformation and upgrading of metallic manufacturing industry and construction sector. The advantages of WAAM technology in rapid manufacturing, design freedom, and energy saving have attracted attentions in the construction field. This research study focuses on investigating the microstructural and mechanical behavior of austenitic stainless steels produced by wire arc additive manufacturing through test programs. The stainless steel plates were first additively manufactured using cold metal transfer technology with three types of feedstock wires (ER304, ER308L, ER316L). Tensile coupon specimens and microstructural observation samples were extracted from the WAAM plates. The electron backscatter diffraction (EBSD) experiments were conducted to identify and analyze the microstructures of the WAAM austenitic stainless steels. Five test orientations, namely θ = 0˚, 30˚, 45˚, 60˚, 90˚ relative to the printing layer direction, were designed to investigate the mechanical properties anisotropy. Two types of specimen surface condition (milled type and as-built type) were considered to assess the impact of geometric undulation. The geometric features of the as-built specimens were obtained using 3D laser scanning. A total of 60 tensile tests with the aid of digital image correlation (DIC) system were conducted to obtain the stress–strain responses of the WAAM austenitic stainless steels. The mechanical properties anisotropy of the WAAM austenitic stainless steels was analyzed in detail.

Experimental investigations on the microstructural evolution and their influence on mechanical, tribological and corrosion performance of wire-arc additive manufactured SS316L structure

The study investigates the feasibility of emerging wire arc additive manufacturing technology to fabricate steel structures. The grain morphology and phase transformation of the WAAM-printed structure have been thoroughly examined and investigated their influence on the mechanical, tribological, and corrosion performance. The structure is characterized by fine equiaxed grains nearer to the cold substrate and coarse columnar grains along the upper regions. The average grain size in the top, middle, and bottom regions of the printed wall is 12.34 ± 5.81 µm, 10.27 ± 2.84 µm, and 4.33 ± 0.89 µm respectively. The higher temperature gradient in the bottom regions led to the ferrite-austenite solidification mode that switched toward the primary austenite solidification mode in the upper layers. The printed parts witness superior mechanical properties with an improved micro-hardness and tensile strength however reduced ductility compared to the conventionally produced steel. The longitudinal direction of the printed parts experienced slightly higher hardness than the transverse. The tribological performance in different regions is investigated under different loading conditions and discovered an improvement in the wear-resistant properties of the fabricated part to its wrought counterpart even at high load conditions. Moreover, comparative corrosion resistance properties of the WAAM and wrought steel were detected with a slightly higher corrosion rate along the upper region in a moderately saline environment with flowing and stagnant conditions. The study detects the dependence of the characteristics properties on the grain morphology and existing phases in different regions of the arc additive-manufactured steel wall.

A comparative study on the microstructure, mechanical properties, wear and corrosion behaviors of SS 316 austenitic stainless steels manufactured by casting and WAAM technologies

Replacing the traditional casting method with wire arc additive manufacturing (WAAM) to produce complex shaped parts will lead to using cost-effective technology even for challenging engineering applications depending on their geometry and number of the parts to be produced. This work performed a comparative study on the stainless steel 316 parts manufactured by WAAM and sand casting to reveal the microstructural, mechanical, wear, and corrosion behaviors. The WAAM components were manufactured using three different cooling dwell times and compared in terms of microstructures with the as-cast and heat-treated cast parts to reveal the properties of the WAAM parts. It was concluded that WAAM is a viable engineering alternative to the casting technology. Results showed that the WAAM and cast parts revealed similar microstructures, including delta ferrite and austenite phases, but the cast parts had a coarser grain and lower amount of delta ferrite due to slower cooling during the solidification. The yield and tensile strength of WAAM parts showed an increasing trend with the increase in dwell time, and on average, their yield strength was ∼1.5 times higher than in cast parts due to the smaller grains and more elevated δ-ferrite content resulting from rapid cooling. Furthermore, the greatest wear resistance was obtained in the cast parts after solution annealing heat treatment followed by water quenching. In contrast the highest corrosion resistance was obtained from WAAM parts produced using a dwell time of 120 sec. In conclusion, WAAM technology can be an excellent alternative to casting technology for producing stainless-steel parts with optimized process parameters.

Microstructural evolution and mechanical properties of Mg-8.1Gd-2.6Y-0.7Zn-0.5Zr alloy by multi-layer wire arc additive manufacturing

Wire arc additive manufacturing (WAAM) of Mg-RE (rare-earth)-Zn alloys is important for meeting the requirements of lightweight large-scale components with high manufacturing flexibility. The Mg-8.1Gd-2.6Y-0.7Zn-0.5Zr (GWZ831K, wt.%) alloys were fabricated through the use of WAAM technology, and the microstructure evolution along the building direction and corresponding mechanical properties were then studied. The as-built sample in this paper was composed of finely equiaxed ɑ-Mg grains, eutectic (Mg, Zn)3(Gd, Y) phase, cubic phase, and γʹ precipitates. Furthermore, due to the in-suit heat treatments that were induced by the multiple thermal cycles, more γʹ precipitates were observed in the middle region. The microstructures at different heights were characterized by alternatively distributed fine equiaxed grains (melt pool boundaries, MPB) and coarse equiaxed grains (melt pools, MP). The mechanical properties of the as-built component were found to exhibit yield strength (YS), ultimate tensile strength (UTS), and elongation (EL) of 159 ± 1.0 MPa, 237 ± 4.0 MPa, and 6.7 ± 0.4 % in the building direction (BD) and 163 ± 5.1 MPa, 242 ± 8.7 MPa, and 7.0 ± 0.7 % in the traveling direction (TD). This demonstrates that the WAAM-processed GWZ831K alloy has good isotropy.

Revealing microstructural evolutions, mechanical properties and wear performance of wire arc additive manufacturing homogeneous and heterogeneous NiTi alloy

Heterogeneous microstructure designs have attracted a great deal of attention, not only because they have the potential to achieve an ideal combination of two conflicting properties, but also because the processes involved in their fabrication are cost-effective and can be scaled up for industrial production. The process parameters in the preparation process have an important effect on the microstructure and properties of alloy members prepared by wire arc additive manufacturing (WAAM) technology. It was expected that the spatial heterogeneous microstructure with large microstructural heterogeneities in metals can be formed through changing the process parameters. In this work, homogeneous NiTi thin-walled component and heterogeneous NiTi thin-walled component were fabricated using WAAM technology by adjusting the heat input. The effects of deposition height and heat input on the microstructure, mechanical properties and wear properties of WAAM NiTi alloys were investigated. The results show that grains were gradually refined with the increase of deposition height in the homogeneous WAAM NiTi component. The ultimate tensile strength of homogeneous WAAM NiTi component increased from 606.87 MPa to 654.45 MPa and the elongation increased from 12.72% to 15.38%, as the increase of deposition height. Moreover, the homogeneous WAAM NiTi component exhibited excellent wear resistance, the coefficient of friction decreased from 0.760 to 0.715 with the increase of deposition height. Meanwhile, the grains in the heterogeneous WAAM NiTi component shows the finest grains in the central region. The ultimate tensile strength of the lower region, middle region and upper region of heterogeneous WAAM NiTi components were 556.12 MPa, 599.53 MPa and 739.79 MPa, and the elongations were 12.98%, 16.69%, 21.74%, respectively. The coefficient of friction for the lower region, middle region and upper region of heterogeneous WAAM NiTi components were 0.713, 0.720 and 0.710, respectively. The microhardness and cyclic compression properties of the homogeneous components with higher heat input were better than those of the heterogeneous components for the same deposition height. The tensile yield strength, elongation and wear resistance of the heterogeneous components were superior compared to the homogeneous components. These results can be used to optimize the WAAM process parameters to prepare NiTi components with excellent mechanical properties.

Implementation of Non Destructive Testing and in-line monitoring techniques on extra-large structures printed with WAAM technology

Grade2XL is a European project funded by the H2020 program that gathers 21 academic and industrial partners. Started in March 2020 for 4 years, the principal objective is to print extra-large structures using the WAAM (Wire Arc Additive Manufacturing) method with a complete control of the fabrication process. Since WAAM is a relatively new technology for printing large specimens, it is important to develop quality assurance methods that can be used during the fabrication and once the structure has been built, which is the focus of CEA List in the project. Regarding methods applied built structures, CEA List has investigated Resonant Ultrasound Spectroscopy (RUS) for the material characterization and more specifically the evaluation of the elastic constants or more conventional ones for the inspection with phased-array ultrasonic techniques (PAUT) or eddy current (EC) for the detection of indications are implemented and optimised them for the inspection of the final structures. Concerning the development of in-line monitoring methods, CEA List has been working on laser Doppler vibrometry (LDV) and X-ray fluorescence (XRF) spectrometry, in order to get structural information during the printing but also detect the appearance of abnormal events and correlate them to the appearance of defects generated during the WAAM process. This proceeding presents the advantages of those methods for the inspection of extra-large structures made by WAAM and discusses the first results obtained in the framework of the project. Keywords: Additive Manufacturing, NDT, Imaging techniques, Eddy current, In-line monitoring, laser vibrometry, X-ray fluorescence spectrometry, Resonant Ultrasound Spectroscopy.

Comparative environmental impact assessment of additive-subtractive manufacturing processes for Inconel 625: A life cycle analysis

This paper presents a life cycle assessment (LCA) approach to compare the environmental impacts of additive-subtractive manufacturing processes for Inconel 625. The LCA follows a cradle-to-gate methodology and employs the Eco-chain Mobius Software, in accordance with ISO 14044 standards. The chosen LCA model enables industries to develop sustainable production techniques by evaluating 18 environmental variables' potential effects on human health, ecosystems, and resource availability. The LCA adopts the midpoint(H) approach from ReCiPe 2016 to comprehensively assess the environmental impacts. In the first case study, a plate is created using the Wire Arc Additive Manufacturing (WAAM) method, followed by post-processing through drilling in both wet and dry environments. The dry condition results in a remarkable 24.23% reduction in environmental impact when the LCA is applied to the entire process, making it the most sustainable choice. In the second case study, a hollow cylinder is manufactured using the WAAM technique, and post-processing is conducted using turning processes under cryogenic, dry, and electrostatic minimum quantity lubrication (EMQL) conditions. The dry environment yields a 16.4% lower impact on the environment, establishing it as the most sustainable choice. Overall, the results from both case studies demonstrate that utilizing WAAM technology in a dry environment leads to the most sustainable manufacturing procedure for Inconel 625. This comparative analysis provides valuable insights to support the development of environmentally friendly production techniques in the manufacturing industry.

H13 tool steel fabricated by wire arc additive manufacturing: Solidification mode, microstructure evolution mechanism and mechanical properties

The critical application value of AISI H13 tool steel in the die and mold industry and the great application potential of additive manufacturing (AM) technology in die manufacturing and repair have attracted extensive attention from researchers. However, there is no consensus on the solidification mode and microstructure evolution mechanism of H13 during AM. The relationship between the unique cellular/dendritic substructures and the grain structures in AM-fabricated H13 components has yet to be fully understood. This work focused on the microstructure and mechanical properties of different regions of the H13 component manufactured by wire arc additive manufacturing technology. Thermodynamic calculations and experimental results confirmed the formation of δ-ferrite during the non-equilibrium solidification of AM. The cellular/dendritic substructure is caused by the solidification of δ-ferrite and austenite together with the accompanying segregation. The results of optical microscopy and scanning electron microscopy, as well as the reconstructed prior austenite grain structure by electron backscatter diffraction (EBSD) all confirmed that the formation and distribution of cellular/dendritic substructures were not directly related to the prior austenite grain. The EBSD pole figures show that although the martensite transformation weakened the preferred orientation of crystals, the martensite phase in the typical structure of the deposition area still had a high texture strength, which may be the main reason for the anisotropic mechanical properties of the H13 component.

Proposition of a model to determine the process parameters for manufacturing thick parts with WAAM technology

ABSTRACT Wire Arc Additive Manufacturing (WAAM) is a metallic additive manufacturing process based on the fusion of metallic wires using an electric arc as a heat source. The challenge associated with WAAM is heat management and understanding bead geometry. All of the process variables, such as travel speed (TS), wire feed speed (WFS), idle time, combine to produce the geometry of the deposited bead that results in the desired component shape. Therefore, determining a method for selecting a good combination of process parameters is critical to obtain a high-quality part. This article presents a study on how to control the WAAM process to produce a thick part of aluminium alloys. An experimental design is determined to study the influence between various process parameters such as WFS, TS, the layer height, or the length of the bead. Different samples are made using a Yaskawa robot, and the classic CMT (Cold Metal Transfer) mode as a manufacturing method. A new manufacturing method is then proposed by adding an important step in the process parameters determination. The results indicate that the length of the bead has a significant impact on the torch speed of the process.

The Effect of Severe Plastic Deformation on the Microstructure and Mechanical Properties of Composite from 5056 and 1580 Aluminum Alloys Produced with Wire Arc Additive Manufacturing

In this study, a composite with alternate layers of 5056 and 1580 alloys was manufactured with wire arc additive manufacturing technology. It is shown that increased strength characteristics of composite material can be obtained with deformation treatment using a high-pressure torsion (HPT) technique. The microstructure and mechanical properties of the HPT-processed material in different structural states were investigated. The HPT-processed material exhibits a high value of ultimate tensile strength (~770 MPa) but low ductility. Short-term annealing at 250 °C and additional deformation with HPT to 0.25 of revolution at room temperature resulted in a slight decrease in the material’s strength to ~700 MPa but provided ductility of ∼9%. Physical mechanisms to improve plasticity in correlation with microstructure evolution are discussed.

Synchronous-hammer-forging-assisted wire arc additive manufacturing Al-Mg alloy

The plastic deformation-assisted wire arc additive manufacturing (WAAM) technology based on the hammer-forging method has essential application prospects in preparing high-dense fine-grain aluminum alloy components. However, the existing interlayer hammer-forging method has limitations, such as insufficient hammering force and high demand for hammering times when obtaining large plastic deformation. To effectively solve these problems, this paper proposed synchronous-hammer-forging-assisted WAAM technology and systematically studied its effects on the macroscopic morphology, microstructure, pores evolution, and mechanical properties of WAAM Al-Mg alloy specimens. The results show that under the synchronous hammer-forging (SHF) condition, a large plastic deformation of 33.97% can be achieved by the 80 N hammer forging force, and the surface flatness of the specimen was significantly improved. The grain size of the specimen was reduced from 105.92 µm in the deposited state to 37.15 µm in the hammered specimen by 64.93% with a significant equiaxed effect. Simultaneously, with the application of SHF technology and the increasing hammer-forging force, the precipitated phase dominated by Al3Mg2 was broken. The pores in the specimen changed from round to narrow and elongated shape with only 0.0065% porosity. The number of pores, equivalent diameter, and surface area were reduced by 68.33%, 13.75%, and 67.24%, respectively. The yield strength and ultimate tensile strength of the hammer-forged specimens reached 250.37 MPa and 315.03 MPa, respectively, which were 36.28% and 8.95% higher than those of the deposited specimens, and still maintained a high elongation rate of 36.11%.

Achieving fully equiaxed grain microstructure and isotropic mechanical properties in wire arc additive-manufactured Mg-Y-Nd-Zr alloys

The thin-wall Mg-3.82Y-2.46Nd-0.56Zr (WE43) alloy component was fabricated using cold metal transfer-based wire arc additive manufacturing technology (WAAM-CMT) and the way in which microstructure evolution influences the corresponding mechanical properties in different height zones was studied. The thin-wall WE43 alloy component was mostly composed of fully equiaxed grains that had low texture strength. As a result of the layer-by-layer deposition, its microstructure exhibited obvious layer characteristics, mainly including melt pools (MP) with coarse equiaxed grains and melt pool boundaries (MPBs) with fine equiaxed grains. The grain size of the thin wall in the building direction decreased from 25.3 ± 1.2 µm in the bottom zones to 22.3 ± 0.7 µm in the top zones, whereas the content of the second phase increased. No obvious anisotropy was observed in the mechanical properties of the thin wall. The top zone specimens were found to have the best mechanical properties with ultimate tensile strength (UTS) of 233 MPa, yield strength (YS) of 153 MPa and elongation (EL) of 10.4%. In comparison to the bottom zone specimens, improvement in the mechanical properties of the top zone specimens resulted from secondary phase strengthening and grain boundary strengthening.

Fatigue crack initiation and propagation of wire arc additive manufactured Al-Mg alloy

Wire arc additive manufacturing technology has many advantages in producing large engineering structures and is being applied in aerospace structures. It is necessary to explore the fatigue failure mechanism of wire arc additive manufactured aerospace aluminum components to ensure these structures' safe application. Crack initiation and propagation behavior for wire arc additive manufactured Al-Mg alloy are investigated under fatigue loading. The microstructure characteristics of different regions are analyzed by metallographic and electron back-scattered diffraction measurements. The fatigue test results show that multi-crack initiation is the fatigue damage characteristic for the additive manufactured parts. The small cracks are distributed in the deposition and layer band zones, and the number of small cracks increases with the cyclic numbers. The main crack initiates from the coarse columnar grain boundaries in the deposition zone, and the final fracture is in the strain concentration zone. The fatigue fracture morphologies show that the fatigue cracks initiate at the pores, non-melted particles, and grain boundaries.

Investigation of microstructural and corrosion behavior of 316LSi structure developed by wire arc additive manufacturing

SS316LSi austenitic stainless steel thin wall was deposited using wire arc additive manufacturing technology, which is known for its high deposition rate and effective material utilization. The optical micrograph revealed the formation of vermicular δ-ferrite, dispersed in the austenite matrix in the deposited wall. The X-ray diffraction patterns confirmed the formation of γ-austenite, δ-ferrite, and chromium carbide (Cr23C6) phases. The SEM and energy dispersive spectroscopy study exhibited the formation of intergranular precipitates. In the magnetic study, ferrite number was found from 3 to 7 in a different portion of the wall which revealed the formation of the ferromagnetic δ-ferrite phase. The Cr and Ni equivalent ratio, 1.66, ferrite number, and presence of vermicular δ-ferrite in the microstructure showed that ferrite austenite can be the mode of solidification in the alloy. The preferred grain growth direction was determined by electron backscattered diffraction analysis to be < 001 > orientation along the build-up direction. In the potentiodynamic polarization and double loop electrochemical potentiodynamic reactivation study, the corrosion rate and intergranular corrosion were correlated to the amount of δ-ferrite and Cr23C6 respectively. The degree of sensitization confirmed that the amount of Cr23C6 formed is least in the lowermost and highest in the central portion of the deposited wall.

The influence of laser shock peening on corrosion-fatigue behaviour of wire arc additively manufactured components

The need for increased manufacturing efficiency of large engineering structures has led to development of wire arc additive manufacturing (WAAM), which is also known as direct energy deposition (DED) method. One of the main barriers for rapid adoption of the WAAM technology in wider range of industrial applications is the lack of sufficient performance data on the WAAM components for various materials and operational conditions. The present study addresses this essential need by exploring the effects of laser shock peening surface treatment on corrosion-fatigue crack growth (CFCG) life enhancement of WAAM components made of ER70S-6 and ER100S-1 steel wires. The experimental results obtained from this study were compared with the CFCG trends from nominally identical specimens without surface treatment and prove the efficiency of the examined surface treatment method for corrosion-fatigue life enhancement and crack growth retardation of WAAM built steel components, regardless of the material type and specimen orientation. Furthermore, the residual stresses in the WAAM built specimens with and without surface treatment were measured to validate the influence of beneficial residual stresses, arising from surface treatment, on subsequent CFCG behaviour of the material. The residual stress profiles show the beneficial compressive stress fields in the surface treated areas which result in CFCG life enhancement. The results from this study make significant contribution to knowledge by evaluating the suitability of WAAM built steel components for application in offshore environments.