Steel Components Research Articles

Fatigue life prediction of rolling bearings based on damage accumulation considering residual stresses

The determination of the fatigue life of rolling bearings is recommended to be conducted using the standard calculation models defined in ISO 281. These models yield reliable results for rotating applications. The standard models are continuously refined to align with advancements in bearing production processes and material improvements. However, when dealing with rolling bearings exposed to complex load conditions including oscillatory movements, as seen in rotor blade bearings in wind turbines, a validated calculation model has yet to be established. In the domain of structural mechanics, fatigue life evaluation for steel components is based on S-N curves. Variable operational loads are treated as load collective, and the load cycle to failure N under given operational conditions is determined through the application of the linear damage rule. This paper introduces a novel model that integrates the linear damage rule with established conventional bearing theories. Within one internal stress cycle, all rolling contacts are regarded as an internal load collective. To evaluate the internal load collective, the stress state at each rolling contact is assessed based on the S-N curve determined in alternating torsional loads. The core rationale behind the selection of an S-N curve lies in the stress criterion τo based on Lundberg-Palmgren theory, which is incorporated in the new model. This paper includes a comprehensive step-by-step procedure for applying the new model, utilizing the cylindrical roller bearing NU 1006 as a reference. The results of this study indicate a favorable agreement between the fatigue life obtained using the new model and those determined according to ISO 281. Furthermore, a new approach is introduced to analytically account for residual stress - es when measured values are available. In this study, by applying this new approach, the results were observed to be in close agreement with the test results. Based on this investigation, it can be confirmed that the new model has the potential to provide reliable results without necessitating the bearing life exponent as well as the correction factors often required in conventional calculation models.

Printing, Debinding and Sintering of 15-5PH Stainless Steel Components by Fused Deposition Modeling Additive Manufacturing.

Metal FDM technology overcomes the problems of high cost, high energy consumption and high material requirements of traditional metal additive manufacturing by combining FDM and powder metallurgy and realizes the low-cost manufacturing of complex metal parts. In this work, 15-5PH stainless steel granules with a powder content of 90% and suitable for metal FDM were developed. The flowability and formability of the feedstock were investigated and the parts were printed. A two-step (solvent and thermal) debinding process is used to remove the binder from the green part. After being kept at 75 °C in cyclohexane for 24 h, the solvent debinding rate reached 98.7%. Following thermal debinding, the material's weight decreased by slightly more than 10%. Sintering was conducted at 1300 °C, 1375 °C and 1390 °C in a hydrogen atmosphere. The results show that the shrinkage of the sintered components in the X-Y-Z direction remains quite consistent, with values ranging from 13.26% to 19.58% between 1300 °C and 1390 °C. After sintering at 1390 °C, the material exhibited a relative density of 95.83%, a hardness of 101.63 HRBW and a remarkable tensile strength of 770 MPa. This work realizes the production of metal parts using 15-5PH granules' extrusion additive manufacturing, providing a method for the low-cost preparation of metal parts. And it provides a useful reference for the debinding and sintering process settings of metal FDM. In addition, it also enriches the selection range of materials for metal FDM.

Metallographic Evaluation of Increased Susceptibility to Intermediate Embrittlement of Engine Valve Forgings Made of NCF 3015 High Nickel and Chromium Steel.

This paper focused on determining the increased tendency of cracking after the die forging process of high nickel and chromium steel. The increase in carbon content in austenitic nickel-chromium steel promoted the tendency of valve forgings to forging intergranular crack on the valve head. Attention was paid to issues related to the chemical composition of the material to be considered when hot forming nickel-chromium steel components. Optical and scanning electron microscopies were used to examine the microstructure and fracture features of the samples removed from a fractured valve head. The embrittlement was due to microcavity formation at grain boundaries. Creep theory at grain boundaries was used to explain crack formation. The tensile behavior was interpreted from the evolution of the microstructure during deformation and referred to intermediate brittleness to explain the effect of carbon. It was found that the increased carbon content of the nickel-chromium steel and the strong undercooling observed at the edges of the valve head are factors that promote a reduction in grain boundary cohesion and enhance intermediate temperature embrittlement. Finally, it was found that the formation of a heterogeneous structure manifested by the presence of grain boundary M23C6-type carbides in the austenitic matrix was most likely related to the occurring brittleness.

Investigation of the in-plane mechanical behavior of timber and steel–timber composite arches

This research investigates the structural characteristics of steel-timber composite (STC) structures through a comprehensive investigation involving five-point bending tests conducted on both the timber arch and the STC arch. The proposed STC arch configuration employs glulam panels bonded to the steel arch using adhesive, effectively restraining the internal steel components and mitigating the risk of buckling. By analyzing the test results, mechanical behaviors of the specimens were observed, including failure modes, load–displacement curves, and load–strain responses. Notably, the ultimate load-bearing capacity of the STC arch exhibited an approximate 28.44% increase compared to that of the timber arch, while maintaining a steel ratio of 10%. The steel ratio, defined as the proportion between the cross-sectional area of the H-shaped steel and the total cross-sectional area, was a critical factor to evaluate both the improvement effect and economic benefits. Additionally, employing finite element models, the influence of steel strength, timber strength, and steel ratio on the ultimate load-bearing capacity was demonstrated. Furthermore, the proposed analytical methodologies can be effectively employed to evaluate the mechanical performance of the STC arch, offering a valuable framework for assessment.

Influence of MnS inclusion characteristics on generation of white etching cracks in 100Cr6 bearing steel

Wind turbine gearbox (WTGB) bearings suffer from premature failures through white etching cracks (WECs). To investigate causes of this failure mechanism, we tested two types of 100Cr6 bearing steel components. We carried out rolling contact fatigue experiments on standard washers and material extracted from a WTGB bearing. These differed strongly in morphology and orientation of non-metallic inclusions (NMIs) with respect to the raceway, especially of MnS-type. While the standard washer did not exhibit WECs formation, the WTGB bearing did - even under moderate conditions (1.9 GPa Hertzian pressure, 107 cycles). We therefore conclude that MnS-inclusions are a key factor in initiation of WECs in WTGB bearings.

Electrochemical study of three new morpholine-based inhibitors for P460N steel in 3.5 wt. % NaCl solution

BackgroundCorrosion of steel occurs due to the rough working environment in which it is used. It accelerates the deterioration of the steel components and results in substantial financial loss. Continuous research has been carried out to prevent or reduce the corrosion of steel and other metals because these materials have so many industrial applications. MethodsThe inhibition performance of three new organic substances, N1-(3-morpholinopropyl)-N1-((pyridine-2-yl)methyl)propane-1,3-diamine (I1), 2‑methoxy-6-(((3-((3-morpholinopropyl)(pyridin-2-ylmethyl)amino)propyl)imino)methyl)phenol (I2), and its reduced form, 2‑methoxy-6-(((3-((3-morpholinopropyl)(pyridin-2-ylmethyl)amino)propyl)imino) methyl) phenol (I3), on corrosion of the P460N in 3.5 wt.% NaCl solution was investigated by potentiodynamic polarization (PDP), EIS, immersion tests, and SEM techniques. Significant findingsA novel material exhibiting superior corrosion protection capabilities for steel was synthesized, and its efficacy was validated through both electrochemical and non-electrochemical testing methods. Comparing the OCP values in the blank and inhibitor-containing solutions shows a negative shift. According to PDP experiments, the highest value of icorr occurs with the P460N electrode in the inhibitor-free solution (79.4 μA.cm−2). Meanwhile, in the case of the highest concentration of I1, I2, and I3 inhibitors, a significant reduction in the corrosion rate was observed, with reductions of 6, 17, and 22 times, respectively. Notably, the reduced form (I3) exhibited exceptional protection against corrosion. PDP results confirmed that the inhibition efficiency reached the highest value of 84.1, 94.3, and 95.5% for I1, I2, and I3 at 2.0 mM concentration. From the EIS measurements, the inhibition performance of inhibitors follows the order I3 > I2 > I1 at equal concentration. Based on the immersion test results and SEM-EDS evaluation, the reduced sample (I3) demonstrated significantly lower corrosion over an extended period, indicating excellent long-term stability in the 3.5% NaCl solution. The electrochemical (PDP and EIS), and non-electrochemical (immersion tests) data confirmed that the inhibition efficiency of the inhibitor of I3 was better than the two other compounds. SEM and EDS analysis showed severe corrosion for the P460N surface without an inhibitor, and corrosion products such as iron oxide and trapped NaCl in porosity appeared very uneven, with different shapes. The study explored four absorption mechanisms: Langmuir, Temkin, Freundlich, and Frumkin. The three new inhibitors were found to adhere to the Langmuir adsorption isotherm with a high correlation coefficient of approximately 0.999. Moreover, these inhibitors demonstrated mixed inhibition behavior for P460N steel in a 3.5% NaCl solution.

Fatigue life prediction of welded joints at sub-zero temperatures using modified Paris–Erdogan parameters

The fatigue life of welded steel components is usually determined by the weldment; in these cases, fracture mechanical approaches are widely used for their prediction. Ferritic steels are known to have a fatigue strength that is dependent on temperature. Therefore, this study evaluates fatigue tests of cruciform joints and transverse stiffeners at different sub-zero temperature levels regarding fatigue life. Simultaneously, the stress intensity factors over the crack length are calculated for the individual experiments using analytical solutions. Then, using the Paris–Erdogan relation with temperature- and material-specific C and m parameters as well as tabular values, the fatigue lives are calculated with analytical solutions and compared with the experimental results. It is shown that the prediction accuracy is significantly increased for the sub-zero temperature range by using temperature-adjusted Paris–Erdogan parameters, as long as the temperature is above the fatigue transition temperature.

Wet sieving and magnetic separation for the treatment of radioactive secondary waste produced from waterjet abrasive suspension cutting

Abstract. Dismantling of reactor pressure vessels and their built-in components is an enormous challenge in the deconstruction of a nuclear power plant. Due to the years of exposure to neutron radiation, the activated components can only be dismantled and packaged remotely. For reasons of radiation protection, preference is given to techniques that can be used underwater due to the shielding effect. A cutting method that meets these requirements is the waterjet abrasive suspension cutting technique (WAS). The cutting tool is capable of slicing metallic internals and other materials using a pure jet of water mixed with an abrasive substance at high velocity and pressure. The process offers numerous technical advantages, but it has a major disadvantage in producing secondary waste. Due to the addition of the abrasive substance, the WAS process produces a waste mixture of inactive abrasive particles and radioactive steel particles (activated by neutron radiation) during the dismantling of steel components in nuclear facilities. Since the steel particles are radioactive when the reactor pressure vessel (RPV) and its internals are dismantled, this particle mixture currently has to be disposed of as radioactive waste. This leads to a doubling of the radioactive waste. Despite the technical advantages, the WAS process used for cutting purposes is a severely disadvantage from an economic point of view, considering the significant disposal costs of the radioactive waste. The research project NaMaSK (wet sieving and magnetic separation of grain mixtures to minimise secondary waste in the dismantling of nuclear facilities), funded by the German Federal Ministry of Education and Research (BMBF), aims to separate the two fractions (abrasive and steel particles) with the help of magnetic separation and wet sieving. For this purpose, a prototype separation system MaSK (magnetic separation of grain mixtures to minimise secondary waste in the dismantling of nuclear facilities) with a magnetic filter and sieve has already been built and tested, and it can separate up to 98 % of the steel particles from the mixture. The separation process aimed to reduce the total amount of secondary waste by reusing abrasive particles for further WAS cutting. In the new test plant NaMaSK, the mode of operation will be converted from a batch process to continuous operation to highlight the economic aspect of the separation process. In this regard, an efficient design of the sieve structure and magnetic filter, followed by process optimisation, will be implemented. These new developments and the first results will be presented at the conference.

Evaluation of the influence of mean stress on the fatigue behavior of notched and smooth medium carbon steel components through an energetic local approach

AbstractIn the present paper, the influence of the mean stress on the fatigue behavior of smooth and notched medium carbon steel components (C45 grade) is investigated through conventional and more advanced design methodologies. Original experimental data are provided for two notched specimen geometries and three different high load ratios (R = {0.7, 0.8, 0.9}). To assess the effect of the mean stress in a larger range, the bulk of fatigue data has been widened through more than 150 tests on C45 steel drawn from literature. The considered experimental data ranged between a load ratio of −2 and 0.9. The mean stress effect has been assessed in a first attempt through well‐established literature models resulting in a data correlation characterized by a large scatter. Finally, an attempt to uniquely consider both geometrical and load ratio effects has been performed through a numerical application of the strain energy density (SED) method. Elevated load ratios (R ≥ 0.7) prove to be highly detrimental for C45 steel with a fatigue life reduction of up to 3 orders of magnitude; however, this effect can be considered with a sufficient degree of accuracy through the SED method.

LUBRICATION OF OFFSHORE MECHANICAL COMPONENTS: TOWARDS SUSTAINABLE & RELIABLE POWER PRODUCTION

As different wave and tidal energy generators advance towards the commercial deployment phase, addressing potential issues related to the lubrication of the machine components integrating the Power Take Off system (PTO) due to the harsh operating conditions encountered in the marine environment becomes even more essential. Environmentally Acceptable Lubricants (EALs) based on water-soluble polymers are proposed as a way to reduce friction and wear of the mechanical components in wave and tidal energy generators. Although these fluids have the advantage of being biodegradable and non-toxic, they have not shown to be as effective as other synthetic fluids, or mineral oils in preventing corrosion, severe friction, and wear, thus increasing the risk of moving parts experiencing premature failure.
 This work explores the potential of different water-soluble polymers to be used in the formulation of EALs that can meet the strict environmental regulations while providing effective protection against wear, and corrosion in offshore operating conditions. To evaluate the potential of these lubricants as an alternative to replace conventional mineral oils, different polymers were analyzed from the point of view of their ability to form an effective full lubricant film that can keep separation between the contacting surfaces, mitigate wear, and prevent corrosion. The rheological properties of these polymers were also studied at different concentrations in order to optimize the performance in the application. The hydrodynamic film build-up properties of EALs formulated with water-soluble polymers with different molecular weight, concentration, and viscosity are reported. The corrosion resistance exhibited by steel components when exposed to the different formulations compared to seawater was an object of examination. The study also aimed to establish correlations between the lubricant film-build up properties, viscosity, and electrical impedance.
 The results showed that high molecular weight polymers can form a separating film at relative high pressure in the low-speed region even at low polymer concentrations. While with the increasing speed, the fluid viscosity becomes more important to sustain a full film between contacting surfaces. With the increasing concentration of polymer in the aqueous solution the open circuit potential (OCP) becomes more negative indicating the deterioration of the steel corrosion resistance.
 The results provide new insights into the design of EALs that can effectively protect the mechanical components of wave and tidal energy generators while minimizing environmental impact. The findings suggest that water-soluble polymers are a promising solution for offshore applications, as they can provide efficient full film lubrication, mitigate wear, and prevent corrosion. These polymers can help to improve the performance and lifespan of offshore power generators while minimizing the environmental impact.

New fire resistance design approach for concrete‐filled cold‐formed steel (CF‐CFS) built‐up composite column

AbstractPrior research investigated the fire resistance prediction of the concrete‐filled cold‐formed steel (CF‐CFS) built‐up columns when subjected to axial compression and high temperatures. However, a complex heat transfer analysis is needed to calculate the temperature development of the steel and concrete components of the composite cross‐section to predict the fire resistance of a composite column, as provided in EN1994‐1‐2. In order to estimate equivalent temperatures for the steel and concrete used in CF‐CFS built‐up column sections, this research provides a series of empirical formulae. A two‐dimensional heat transfer analysis calibrates a finite element model to estimate temperature across the CF‐CFS built‐up column sections. The concrete infill was simplified by separating into an inner and outer core. The empirical formulas' accuracy was assessed by comparing them with 2D heat transfer analysis results. Finally, the fire resistance of a CF‐CFS column was obtained using numerical simulation and compared with the analytical prediction following EN 1994‐1‐2 incorporated with the current empirical formulation. The results showed a high accuracy of the empirical formulation to determine the equivalent temperatures of the steel and concrete core components.

Heat treatment effect on microstructure evolution of two Si steels manufactured by laser powder bed fusion

Additive manufacturing technology represents a valid alternative for the production of ferromagnetic components in Si steels (FeSi) with high Si content. In this work the effect of heat treatments on microstructural evolution of two steels with standard (3.0 wt.% - FeSi3) and high (6.5 wt.% - FeSi6.5) Si content manufactured by Laser Powder Bed Fusion (L-PBF) was investigated. Four different temperatures ranging from 900 °C up to 1150 °C (soaking time of 1 h) were tested for each steel.In as-built condition, all the grains of FeSi3 are columnar with the [100] direction parallel to the building direction (BD) whereas in the case of FeSi6.5 there is a mix of columnar and equiaxed grains. The average grain size of FeSi6.5 (11.3 ± 0.6 μm) is about one order of magnitude lower than that of FeSi3 (103.1 ± 5.2 μm). EBSD analysis revealed that there is a prevalence of low-angle boundaries (LABs) in FeSi3 and of high-angle boundaries (HABs) in FeSi6.5. The different initial microstructure affects the response to heat treatments of the two alloys: grain size and shape of FeSi3 do not remarkably change, on the contrary significant grain growth takes place in FeSi6.5 without a weakening of the [100] texture. No brittle ordered phases were detected in as-built and heat treated samples of both materials. The results indicate that heat treatments at high temperature can be exploited to improve the magnetic characteristics of printed FeSi6.5 and reach similar properties of commercial steels.

Parametric design and dynamic analysis of a hybrid steel‐FRP bridge.

AbstractIn Gothenborg, Sweden a new pedestrian bridge was needed. In the proposed design, the bridge was composed of a Fiber‐Reinforced Polymer (FRP) deck and a main steel structure, which provided two intermediate supports to the deck. The design of the main steel structure was the responsibility of Systra AB in Sweden, while the FRP deck was designed by Royal HaskoningDHV in the Netherlands. The main design challenge met was the dynamic behaviour of the bridge due to human induced vibrations. Besides the technical challenges, there were also challenges to find a reliable and efficient way to for the two companies to collaborate while in two different countries. To accommodate these challenges, it was decided to create a parametric coordination model, in Rhino/Grasshopper, from which the design and calculation models were generated. This coordination model served as the single source of truth ‐ ensuring that at any time both companies had an up‐to‐date version of the model. This proved crucial as the dynamic behaviour of the bridge was significantly influenced by the interaction between the steel and FRP components. Due to the parametric nature of the model, a variation study was possible, where a total of 200 variants were produced to find an optimal design.

Fatigue performance of preloaded bolted connection with oversized holes

AbstractMoving towards a more sustainable and circular infrastructure has increased the demand for demountable connectors in hybrid structures combining steel, concrete, and nowadays FRP composite components. Large, prefabricated components need to be transported to the construction site and assembled by means of bolted connections for easy reuse of the components. Slip‐resistant connections are required for such hybrid structures in bridges, which are usually provided by injection or preloaded bolts. The former satisfies the need for large tolerances during execution. However, the behavior of such injection bolts depends on the environmental conditions and the resin complicates the installation and demountability. The current practice of preloaded bolts uses standard hole clearances that do not provide sufficient tolerance for the assembly of large structural components made of different materials and many connectors. This paper focuses on the fatigue performance of preloaded bolted connections with excessively oversized holes that could provide sufficient tolerance for execution. Double lap bolted joints for two different bolt‐hole diameters, regular and 60 mm oversized, are tested under cyclic loading and the increase in slip displacement during the load cycles is compared. The static performance is numerically obtained in terms of residual stiffness, slip and ultimate resistance. It was found the stiffness variation between normal holes and significantly oversized holes is insignificant.

Influence of ECM process parameters on SS316 material

Electro-Chemical Machining (ECM) seems to be a hopeful technique in the production area of automobile manufacturing and other productions. In recent years, the demand for stainless steel (SS) micro products and components has evolved significantly in fields such as biotechnology, electronics, optics, medicine and so on. This stainless-steel material is ideal for hygienic environments because it is easily sterilized and corrosion resistant. The process parameters of ECM for stainless steel material are investigated experimentally in this study. The SS-316 alloy was chosen to influence the electrochemical machining process with different electrodes and to investigate process parameters using SEM analysis. The tool material has been changed to investigate the improved quality of ECM process parameters.

Teaching Research on the Course of Design of Steel Structures Based on Practical Tests: A Case Study on Design of Columns in China

As one of the most important course in the field of civil engineering, the “Design of Steel Structure” is attracting attentions from college teacher in China. The complex failure modes or buckling modes of steel components result in comprehending deviation of students between theoretical models and engineering practice. This paper proposes a teaching research on the course based on practical tests, and presents a case study on design of steel columns in China. The buckling modes and finial failure modes of the cold-formed steel (CFS) columns were visually shown in the tests, and they were compared to the theoretical presentations in textbooks. Besides, a standard testing-teaching procedure is also recommended for further teaching research for other course closed to the engineering practice.

Load‐carrying capacity of Vierendeel bridges in Mechelen

AbstractFrom 1930 to 1960, in Belgium, steel railway bridges were regularly designed using the vierendeel system. Three railway lines cross the Mechelen‐Leuven canal in the town of Mechelen, providing a unique example of this type of application. Two of these bridges, which were constructed in 1953 were renovated in 2021–2022, including the installation of a new rail fastening. It was discovered that the 1936‐built third and oldest bridge had multiple cracks, mostly in the vertical members of the Vierendeel structure. Furthermore, secondary components like longitudinal beams and cross beams are severely harmed by corrosion. As a result, uncertainty grew over this bridge's ability to support loads. The monuments organization promotes the preservation of these old structures. The material properties, as well as the load‐bearing capacity and the fatigue strength, were evaluated by a thorough experimental and numerical investigation. The results of the examinations suggest that the significant strength variation of the steel components may be the cause of the cracking. It is more likely that cracks developed during the bridge's construction and subsequent repairs than that fatigue is to blame. In conclusion, the arrangement of the three bridges is too special to be destroyed and replaced, and the third bridge may also be sufficiently repaired and rebuilt for long‐term further use.

Adhesive bonding of secondary steel components for offshore wind turbines

AbstractOffshore wind turbines consist of the main components tower, nacelle and rotor blades. Additionally, numerous secondary components are connected to the primary structure. These include amongst others boat landings, platforms, cable protection tubes and corrosion protection systems. Usually, these elements are connected to the primary structure by welding or bolts. Both joining techniques reduce the fatigue performance of the primary structure by inducing geometric and/or metallurgical notches. In contrast, by fastening the secondary components by adhesive bonding, no geometric or metallurgical notches are induced in the primary structure. Furthermore, the bonding can be carried out directly on the coating. In contrast to welded or bolted joints, adhesively bonded joints require a differing geometry that allows large bonding areas. This paper highlights the results of experimental investigations regarding the load bearing behaviour of adhesively bonded secondary components under a combination of lateral load and bending varying different geometrical parameters.

Rotating bending fatigue behaviour and quasi‐static tensile properties of Wire Arc Additively Manufactured 308L stainless steel

AbstractWire Arc Additive Manufacturing (WAAM) is a direct energy deposition method used to manufacture steel components by using an electric arc as a heat source to melt a metal wire and deposit it layer by layer. In this study, monotonic tensile tests, standardized Charpy impact tests, and rotating bending fatigue tests are executed to characterize the mechanical properties of WAAM 308L stainless steel using specimens extracted from additively manufactured plates. In particular, monotonic tensile properties are investigated in three directions: that is 0, 90, and 45 degrees with respect to the plane of deposition, whereas the fatigue strength is quantified for one direction only, i.e. 90 degrees since this is deemed to be the weakest.The mechanical characterization highlights that WAAM 308L SS shows an anisotropic behaviour, an enhanced strain‐rate sensitivity, and an overall reduced yield strength as compared to the base material 308L. The anisotropic material behaviour is explained by the microstructure morphology since the austenite grains form anisotropic columnar zones due to an uneven heat profile during production. During the fatigue tests, the relatively high strain rate sensitivity causes susceptibility to self‐heating at relatively low loading frequencies, i.e. below 100Hz.

Robot supported Wire Arc Additive Manufacturing of Steel Columns

AbstractWire Arc Additive Manufacturing (WAAM) is a robot‐controlled welding process used to build up three‐dimensional structures in steel. Like other Additive Manufacturing (AM) technologies, WAAM allows for geometrically‐complex structures to be manufactured which may be unfeasible using conventional methods. Over recent years, WAAM has also gained prominence in the fields of architecture and civil engineering, with applications ranging from fully‐printed steel bridges to individualized steel components. This paper presents the additive manufacturing process of large‐scale applications, focusing on steel columns with circular hollow cross‐sections (CHS). The paper highlights the specific features of the necessary welding and process parameters before the manufacturing process is described in detail. Digital models and welding trajectories are generated with Parametric Robot Programming (PRP) and serve the robot‐controlled printing process. The AM itself is monitored by multiple process‐control checks giving information about resulting weld thicknesses, heights and welding errors influencing the manufacturing strategy of the CHS columns. To be able to make a closing statement about the load‐bearing capacity of the WAAM‐manufactured CHS, final load tests on (stub) columns are carried out.