Low Heat Input Research Articles

The properties of laser-clad coatings made of NiCrBSi alloy and recycled tungsten carbides

Tungsten carbide hard metals are one of the most known and successful powder metallurgical products used in environments where severe wear conditions prevail. Since tungsten belongs to the list of critical raw materials for the European Union (EU), its recycling is highly desirable. In this paper, recycled tungsten carbide powders fabricated by the zinc-reclaim process where mixed with NiCrBSi matrix and deposited with one-step laser cladding using a coaxial powder feeding on mild steel substrates. Prepared clads were tested in low-stress rubber wheel abrasion tests and compared with clads produced from commercial macrocrystalline (WC) and cast and crushed eutectoid WC/W2C reinforced clads. The results showed that recycled WC induced porosity in clads when produced with ‘production’ laser cladding parameters due to small carbide size resulting in poor wear performance. When laser-clad with lower heat input and productivity, pore-free clads with excellent wear performance were obtained.

Process advantages of laser hybrid welding compared to conventional arc-based welding processes for joining thick steel structures of wind tower

The most common welding processes when joining thick-walled steels in the industry are arc-based welding processes such as GMAW or SAW. For this purpose, the sheets are joined in multi-layer technique, which can lead to productivity losses due to high welding times. The process-specific challenges in welding thick steels using multi-layer technique relate to the high heat input from the process. Therefore, alternative welding processes are being actively sought. A suitable alternative is provided by beam-based welding processes such as the laser hybrid welding processes, which are characterized by deep penetration welds and lower heat input. With implementation of the laser hybrid welding process in the heavy industry, such as the wind tower industry, economic benefits can be reached such as the increase in productivity by reducing the layer number, and the lower consumption of filler material and energy. When comparing SAW welded 25 mm thick steels in five to six layers and single-pass laser hybrid welding, the welding time can be reduced more than 80 % and the costs of filler material, flux and energy can be saved up to 90 %. However, the industrial use of the laser hybrid welding process is still limited to applications, where the material thickness does not exceed 15 mm due to some process-specific challenges such as the sagging, sensitivity to manufacturing tolerances such as gaps and misalignment, limited filler wire mixing, and deteriorated mechanical properties resulting from high cooling rates. To overcome these challenges, a contactless electromagnetic backing based on an externally applied AC magnetic field was used. Eddy currents are induced due to the oscillating magnetic field, and an upward-oriented Lorentz force is generated to counteract the droplets formed due to gravitational forces. It allows to weld up to 30 mm thick structural steels in a single-pass with a 20-kW fiber laser system. Additionally, the gap bridgeability and the misalignment of edges were increased to 2 mm when welding 20 mm thick steels. With the aid of the AC magnetic field, a vortex was formed in the weld root, which had a positive effect on the filler wire mixing. A further significant advantage of the EM backing was the possibility to expand the process parameter window to maintain desired cooling times and mechanical properties, without suffering adverse effects concerning the root quality of the weld.

Effect of reducing heat input on autogenous TIG welding of Ti–6Al–4V alloy

3 mm-thick Ti–6Al–4V alloy plates were welded in butt joint configuration through autogenous TIG welding method using a trailing gas shielding arrangement. After attaining full penetrated weld joint with appropriate heat input, subsequent experiments were conducted by reducing the heat input, which was obtained through combination of higher welding current and scan speed. An in-depth microstructural analysis of the weld joint executed under different heat input conditions shows a strong correlation with the microhardness, tensile strength, and flexural strength of the weld joint. A significant improvement in the mechanical properties of the weld joint was perceived for employing lower heat input. Alteration in the primary-α, primary-β, and martensite-α phases, due to the variation in heat input, amended the mechanical properties of the weld joint under lower heat input condition. With the reduction of heat input from 0.406 to 0.232 kJ/mm, the tensile and flexural strengths of the weld joint increased from 1020 to 1070 MPa, and from 1015 to 1950 MPa, respectively. The tensile strength of the joint reached up to 98% of the base material at minimum heat input (0.232 kJ/mm). The experimental results show the potential of TIG welding for joining Ti–6Al–4V alloy under low heat input condition.

Evaluation on the performance of sustainable wire arc additive manufacturing using micro plasma arc welding

Metal additive manufacturing has gained popularity due to its significant advancement in minimising waste. The product design using additive manufacturing (AM) does not require mould and less material required, which is less waste. In this way, AM has the potential to transform the manufacturing industries towards greater sustainability. Besides, AM allow more complex designs and shape than conventional manufacturing. Wire arc additive manufacturing (WAAM) is one of the most popular metal AM that has received significant attention due to its usefulness for localising, repairing, and modifying instead of discarding and replacing entire components. However, conventional welding technology faced the issue of significant heat input, low surface quality, and low dimensional accuracy of WAAM components. Micro-plasma arc welding (MPAW) is a new alternative to the WAAM process. The speciality of MPAW is low current provided of 1A to 25A current range, leading to low heat input and energy-efficient manufacturing. The present study shows various metallic structures developed using an MPAW-based WAAM system, and the relative error between the CAD model and four different structures was determined. Overall, the study outcome shows the geometric uniformity of parts produced with an MPAW-based WAAM system and demonstrates smooth surface finish can be obtained.

High-Speed Laser Beam Welding of Magnesium Alloy AZ31 for Enhancing the Mechanical Properties

Laser beam welding is still the focus of research all over the world since new laser sources with more brilliance, higher power, or higher efficiency are being developed. High brilliance leads to thinner fibers when solid-state lasers are used. For welding applications, a thin beam, respective a small focus spot is recommended for low heat input resulting in less deformation. The edge preparation of the welding pieces must be as accurate as possible, and a zero gap is recommended. In earlier research, it was shown, that the gap bridging capacity could be enhanced by the wobbling of small focus spots, as well as refining the grain size in the weld zone by decreasing the focus diameter. Inventions in the optics, like the beam splitting into a core and a ring part, avoid the use of a scanner and can lead to better gap bridging. Nevertheless, the use of a brilliant beam, resulting in a small focus in combination with high power can result in very high welding velocities, just limited by the used machinery. In the present study, a disk laser with 4 kW maximum power and 100 μm focus spot was used to weld 2 mm thick magnesium AZ31 sheets at speeds up to 20 m/min. As expected, the seam width becomes smaller with raising velocity, and some underfill and access material occurred on the surface and the root of the welded sheets. Surprisingly, the texture of the weld seam changed from random at low velocity to a more pronounced texture at high speed with respect to the basal texture of the plate base material. This influences the mechanical behavior, namely the strain to fracture, of the welded joints positively. The high-speed weldments are compared to state-of-the-art weldments of magnesium AZ31, in terms of mechanical strength and elongation to fracture, based on the texture analysis.

The effect of weld bead heat input on the performance of thick 3CR12 stainless steel welds

3CR12 is a low cost special stainless steel containing 12% chromium. It is widely used in material handling, road transport, rail transport, power generation and petrochemical applications due to its favorable corrosion performance. 3CR12 is a weldable material, but it has challenges such as poor ductility, poor toughness of 3CR12 stainless steel welds, unfavorable microstructure and cross-sectional properties of the weld bead. This is due to the welding heat input and heat transfer across beads, which causes cracking due to property changes. When welding a thick stainless steel section, the hardest heat affected zone (HAZ) is created due to uneven heating and cooling in the weld metal and base material, which is susceptible to cold cracks and residual stresses, resulting in welding defects and unfavorable material properties. Welding thick 3CR12 stainless steels can be accomplished by using a variety of welding techniques. In order to restore undesirable material qualities, the majority of welds require a post-weld heat treatment (PWHT). However, critical PWHT factors such as duration, weld geometry, and unsupported loads during the hot phase of the weld do not always allow the process to be effective. This process results in prolonged downtime since the holding time in the PWHT cycle can be very long, especially with thick-walled 3CR12 steel members. There are other methods that are currently used to weld or repair thick 3CR12 steels. Among these other methods, the use of controlled temper bead welding technique which potentially could mitigate the above mentioned problems is mentioned. The approach involves using the heat input of the weld bead as a way of introducing the heat into the previous weld bead. This is achieved by varying the heat input in order to improve the mechanical performance of the previous weld bead and thus the overall weld integrity. Welding procedures for 3CR12 recommend the use of minimum heat to avoid weld defects and unfavorable material properties. This study was carried out to investigate the effect of the heat input of the weld bead on the mechanical properties of thick welds made of 3CR12 stainless steel. By utilizing inert gas (MIG) welding, two heat input levels were used in the process: low heat input averaged at 1.53 kJ/mm and high heat input averaged at 2.1kJ/mm. The heat input was varied by changing the welding parameters, for example the average welding voltage ranging from 28V to 30V, the average welding current from 120 A to 150 A and the average feed rate between 1.77mm/sec to 2.0mm/sec.

Microstructure and mechanical property of Ti/Cu ultra-thin foil lapped joints with different weld depths by nanosecond laser welding

In present study, 50 μm thick Ti/Cu pure metal ultra-thin foils are successfully lap-welded by a nanosecond fiber laser. The joints with adjustable depths are obtained by controlling the laser energy input precisely. The microstructure and mechanical properties of Ti/Cu joints with different depths are well analyzed, respectively. In the joint with smaller penetration depth of 10 μm, thin band-like Ti/Cu intermetallic compounds (IMCs) are formed, while in the joint with a larger penetration depth of 40 μm, thicker band-like Ti/Cu IMCs and sizable bright dendritic Ti2Cu phases are formed, since more Cu element are involved in the chemical reaction in the joint with penetration depth increasing. The tensile test results show that the weld with 10 μm penetration depth has the best tensile strength up to 240 MPa, which is mainly due to less IMCs and low heat input in the weld. In addition, the fracture mode of the joint is classified into two models, including brittle quasi-cleavage fracture on the Ti side fusion zone (FZ) and ductile fracture on the Cu heat affected zone (HAZ), respectively, depending on the penetration depth above or below 30 μm.

Microstructure evolution and mechanical properties of laser-welded joints of 1.2 GPa-class quenching and partitioning steel

Laser welding of 1.2 GPa-class cold-rolled quenching and partitioning steel with martensite + retained austenite microstructure was performed at different heat inputs ranging from 91–240 J·mm−1 using a CO2 laser. Scanning electron microscopy, electron backscatter diffraction, and uniaxial tensile testing equipped with digital image correlation were employed to characterize the microstructural and mechanical evolution of the joints. The results revealed that the fusion zone and upper-critical HAZ comprised full martensite with high microhardness. The HAZ contained a narrow softened zone with a minimum width of ∼0.6 µm and at least 48 HV microhardness drop because of the martensite tempering. Martensite decomposition and precipitation of carbides were noticeable at higher heat inputs, so that the hardness of the softened zone was declined. At the welding heat input of 91 J·mm−1, the yield and tensile strengths were 841 and 1270 MPa, respectively, which represented reductions of 5.5 and 0.78% compared to the base material properties. The joint efficiency of 99.2% was achieved at the lowest heat input. The tensile deformation was primarily concentrated in the softened zone and was small in the fusion zone. However, the participation of the base material to tensile deformation was enhanced at lower heat inputs, leading to higher elongation values up to ∼11.9% during tensile testing.

Numerical Evaluation of Heat Transfer and Conversion Efficiency by Tube Design and Flow Configuration for a Compact Steam-Methane Reformer

In the chemical industry, hydrogen (H2) production through steam-methane reforming is a well-established process. With the growing demand for H-fueled vehicles and charging stations, there is a need for compact reformers with efficient heat transfer capabilities. In this study, computational fluid dynamics simulations were performed to evaluate the methane (CH4) conversion and heat transfer efficiency of various reformer designs. These designs include single, double, and triple tubes, each with parallel- and counter-flow configurations between the reformate feed and heat source. The findings revealed substantial disparities in methane conversion between the tube designs and flow configurations. Notably, the triple-tube design outperforms single and double tubes, exhibiting higher methane conversion and improved heat transfer efficiency. This superior performance is attributed to the larger wall area facing the heat source and additional heat recovery from the reformate flowing in the inner annulus. This led to the highest temperature at the catalyst exit among the cases, increasing methane conversion, and the lowest reformate temperature at the reformer tube exit, which is also beneficial for the subsequent water–gas shift reaction process. Installing external fins on the reformer tube provided a more effective enhancement of heat transfer than using internal fins in the catalyst section. Regardless of the tube design employed, the counter-flow configuration consistently enhanced the heat transfer efficiency, resulting in 4.6–11.9% higher methane conversion than the parallel-flow configuration. Consequently, the triple-tube design with the counter-flow configuration achieved the highest methane conversion, offering flexibility in the reformer design, including the potential for lower heat input and a reduced catalyst volume.

Fatigue behavior of 8 mm thick steel butt joints performed with hybrid laser arc welding

In the present research, the hybrid laser arc welding (HLAW) process has been applied to join 8 mm thick structural S355J2N steel under 1G configuration. Welding tests were performed at the Laser Welding Advanced Center available at the University of Cadiz, Spain. Different experimental welding parameters were fitted to obtain sound butt welds. The welds were subjected to different quality control tests, including visual inspection, metallographic characterization, microhardness measurements, and tensile and fatigue tests. The HLAW tests were performed at higher welding rates in 1G configuration than previously reported for 8 mm thick steels. Complete penetration was achieved in all welds, presenting suitable geometries without defects such as cracks, root humps, or porosities. Microhardness values measured at different welding zones were always below 350 HV. All welds broke at the base metal in the tensile tests. The present contribution reports novel fatigue results for these butt hybrid welds. The samples welded at the highest welding rate (2.5 m/min) were the ones providing the best fatigue response, due to the lower heat input applied under this condition.

Microstructure and mechanical properties of AISI 410S ferritic stainless steel narrow gap weld using flux strip constraining arc welding

The achievement of high comprehensive mechanical properties in welded joints of ferritic stainless steels has attracted considerable attention in the manufacturing industry. Here, a low heat input flux strip constrained arc welding (FSCAW) was performed on a hot-rolled AISI 410S sheet. Defect free joints with a small HAZ width were obtained by one side welding both sides formation. The microstructure of HAZ consists of fine ferrite grains and a small amount of M23C6-decorated martensite due to short high-temperature residence time and rapid cooling rate, resulting in high toughness and hardness. Influenced by the stirring effect of the constraining arc and the promotion of heterogeneous grain nucleation by Ti-rich MX particles originating from the transition of alloying elements in the flux strip, the fusion zone (FZ) exhibits a unique precipitates-strengthened martensite+austensite uniform microstructure with weak martensitic texture. This translates into a simultaneous increase in impact toughness and hardness of FSCAW FZ compared to the MAG joint with a non-uniform mixed microstructure, strong martensitic texture, and large grain size. This work establishes the potential for using FSCAW welding to join ferrite stainless steels.

Mechanism of columnar to equiaxed to lamellar grain transition during wire-laser directed energy deposition 205 C aluminum alloy utilizing a coaxial head: Numerical simulation and experiment

The microstructure under various conditions shows noticeable differences in the wire-laser directed energy deposition (DED) method using a coaxial head due to the intrinsic properties of aluminum alloy wire materials and the intricate heating process involved. The impacts of varied heat inputs and substrate preheating temperatures on solidification and microstructure evolution were explored in this study. A coupled model, including macroscopic finite element and microscopic cellular automata with interpolation, was employed to investigate the temperature field, thermal cycles, solidification parameters, and microstructure evolution under varied process parameters. This study revealed the transformation of four grain forms in the deposition layer, namely, lamellar grain, equiaxed grain, equiaxed fine grain, and columnar grain, through a comprehensive dynamic simulation of the microstructure. Quantitative research was conducted to determine the solidification region of equiaxed grains and the average length of columnar grain amid solidification under varied crystallization parameters. The findings demonstrated that under a lower heat input and preheating temperature, equiaxed fine grains are generated at the lower region of the deposition layer, while lamellar grains are formed above the equiaxed grains at the upper region of the deposition layer, which is similar to the morphology of a cast microstructure. The typical primary dendritic distance of columnar grain diminishes with the enlargement of the cooling rate and temperature gradient. The findings of this study offer a theoretical framework for regulating the microstructure of aluminum alloy deposition layers manufactured via wire-laser DED technology using a coaxial head.

Enhancing microstructure and mechanical properties of laser powder bed fusion-fabricated AlSi10Mg alloy through tailored friction stir processing and post-heat treatment

In this study, a series of advanced processing techniques is employed to control the internal structure and improve the mechanical properties of AlSi10Mg alloy fabricated via laser powder bed fusion (L-PBF). In the L-PBF, AlSi10Mg sheets are subjected to friction stir processing (FSP) under low heat input conditions. The main objective of this study is to eliminate microstructural defects and refine the microstructure while maintaining a high tensile strength. FSP effectively refines the grain structure but decreases the strength significantly owing to the thermal cycle. Various post-heat treatment strategies have been proposed to optimize the microstructure and strength of AlSi10Mg alloys as well as to address the strength reduction issue. Samples in different processing stages are characterized using optical microscopy (OM), field-emission scanning electron microscopy (FE-SEM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), as well as tensile and hardness tests. Notably, the FSP + direct aging (FSP + DA) treatment significantly enhanced both the ultimate tensile strength (UTS) and yield strength (YS) without compromising the ductility achieved after FSP. By applying the strengthening model, the YS contributions of the main strengthening mechanisms in the Al matrix and Si phase at different processing stages are quantitatively analyzed. The estimated YS values are in good agreement with the experimentally measured values.

Processability of High-Speed Steel by Coaxial Laser Wire Deposition Technology for Additive Remanufacturing of Cutting Tool

The recently introduced Coaxial Laser Wire Deposition technology can become a new promising method for remanufacturing high-complexity and expensive cutting tools (e.g., flat broach), which will have a significant impact on their service life. In addition, it is an innovative approach to tool management. An analysis of the feasibility of processing cobalt-added HSS powder steels was carried out for single clads and multilayer structures. The effect of process parameters (laser, beam power, travel speed, wire feed rate) on geometric properties, hardness and microstructure was discussed. In order to avoid cracking during multilayer deposition, an additional preheating to 320 °C was applied. Two sets of process parameters with high and low heat input were obtained. Both sets lead to crack-free structures that fulfill geometric (≥2.5 mm in height) and hardness (≥700 HV) requirements.

A hybrid shoulder to achieve a significant improvement in tensile strength and fatigue performance of friction stir welded joints for Al–Mg–Si alloy

In this paper, a hybrid shoulder friction stir welding (HS-FSW) process was developed combining the advantages of rotational shoulder friction stir welding (RS-FSW) and non-rotational shoulder friction stir welding (NRS-FSW). Both static and fatigue performance of the HS-FSW Al–Mg–Si alloy joints were examined and compared with those of the RS-FSW and NRS-FSW joints. The ultimate tensile strengths of the joints welded by HS-FSW are increased by 17.3 % and 6.7 %, compared with those of RS and NRS FSW, respectively. Besides, fatigue strengths of HS-FSW joints grow by respective 25.4 % and 1.8 %. For a better understanding of the significant improvements, the fatigue crack propagation (FCP) test and residual stress measurement were carried out. FCP test indicates that the advancing side (AS) is the most sensitive zone for FCP. The residual stress measurements suggest that the HS-FSW joint has the lowest distribution amplitude of residual stress compared with that of the RS-FSW and NRS-FSW joints. Based on above evolution, an assessment is firstly conducted, which reveals that the axial force and the lower heat input to mitigate the amplitude and the peak value of tensile stress during welding, jointly contribute to the superior imprisonment of the tensile strength and fatigue strength of the HS-FSW joints.

Corrosion fatigue behavior of X65 pipeline steel welded joints prepared by CMT/GMAW backing process

The corrosion-fatigue behavior of X65 welded joints, processed by cold metal transfer (CMT) and gas metal arc welding (GMAW) backing, was examined. The application of the CMT backing process led to a 22% increase in the corrosion-fatigue performance, which was attributed to the optimization of the microstructure (synergistic cracking-arrest ability of acicular ferrite (AF) and grain boundary ferrite (GBF)) and the reduction in the stress concentration at the weld root. Nonetheless, a lower heat input contributed to a consequent decrease in corrosion-fatigue performance. In addition, H2S corrosion fatigue was governed by the combined effect of anodic dissolution and hydrogen embrittlement.

Optimization of CMT welding process parameters of dissimilar hot rolled E250 and polymer sandwich steel lap joints

Lap joints of 1.5 mm thin sheets of dissimilar hot rolled E250 with polymer sandwich steel (MPM) were produced by cold metal transfer (CMT) process, closer to the real application. The polymer layer polystyrene-butadiene-styrene sandwiched between two DC06 sheets of MPM was found to be intact at significantly lower heat inputs (0.16 − 0.24 kJ/mm), which otherwise had been quite challenging during TIG welding leading to huge rejections. After several iterative trials for acceptable weld quality, experiments were conducted as per L9 orthogonal array, Taguchi technique with welding speed (WS), wire feed rate (WFR) and welding torch orientation (TO) as the process parameters. The joints were investigated through optical macrograph, micrographs, hardness, tensile lap shear tests and fractography on the fractured specimen. Optimum parameters were determined for maximizing shear strength. The sample with optimized parameters exhibited 6% improvement in shear strength achieving 152.09 MPa and polymer layer retention. ANOVA analysis suggested WS to be most significant parameter with 69.85% contribution affecting shear strength. Coefficient of determination (R 2) for the shear strength was 87.26% derived from the linear regression model. Significantly, lower error 0.96% computed from the confirmatory test concluded very effective optimization. Highlights Thin sheets of polymer sandwich steel (MPM) sheets were joined successfully with hot rolled E250 sheet without thermal disengagement of the polymer layer in MPM by CMT welding. Under optimal parameters MPM/E250 joints exhibited excellent mechanical properties. Fractography analysis revealed ductile failure mode. The error between experimental and predicted results by Taguchi was significantly lower and very well within the acceptable range.

Superior strength-ductility synergy of wire-arc directed energy deposited Mg-Al-Si alloys mediated by sub-rapid solidification

Here we propose to employ wire-arc directed energy deposition (WA-DED) to tune the microstructure and the mechanical property of Mg-Al-Si alloys, on the basis of its sub-rapid solidification effect. According to finite element analysis, WA-DED shows higher cooling rate than conventional casting, reaching 598.3 K/s for Mg-Al-Si alloy, and the lower heat input, the larger cooling rate of WA-DED. Significant microstructure refinement is thus achieved, with reduced grain size and Mg2Si particle diameter. The transition from hypereutectic to fully eutectic microstructure is triggered by reducing the heat input. Compared with the as-cast alloy, WA-DED alloys demonstrate higher ultimate tensile strengths (UTS) at both room- and high-temperature (150 ℃) properties, increasing by 50.1% and 30.3%, respectively. The superior strength-ductility synergy for Mg-Al-Si alloys results from the microstructure tuning via sub-rapid solidification of WA-DED.

Investigation of the thermal behavior during the direct writing metal additive manufacturing

In metal additive manufacturing, thermal behavior significantly influences the quality of formed parts. Direct writing metal additive manufacturing (DWMAM) technology distinguishes itself from other metal additive manufacturing technologies, which use laser or electron beam as the heat source, due to its extremely low heat input and slow heating and cooling rate. This greatly reduce the difficulty of regulating the thermal behavior during the additive manufacturing processes. This article focuses on a systematic investigation into the thermal behavior of the DWMAM process, employing theoretical analysis, simulations, and experimental research. A transient heat transfer model was established to characterize the formation of the first layer, followed by comprehensive simulations and experimental investigations of both the first-layer formation and the subsequent deposition of multiple layers. The temperature variation predicted by the mathematical model is consistent with the simulation and experimental results. The results showed that the maximum heating and cooling rates in DWMAM processes are hundreds of K/s. Additionally, slower writing speeds and higher heating powers result in increased thermal input. An appropriate thermal input can achieve favorable interlayer metallurgical bonding and high-quality formed parts. The research conducted in this study on the thermal behavior of the writing process will provide theoretical and experimental guidance for DWMAM and lay a solid foundation for the further advancement of this technology.

Improving the stability of the friction stir channelling technology via a cooled copper backing plate

The development of the friction stir channelling (FSC) technology has a potential to revolutionize the manufacturing industry, providing an innovative way to produce continuous sub-surface channels in monolithic components in a single step. However, the process generates heat that can lead to defects and loss of stationarity, affecting the quality of the channels produced and the process’ efficiency and control. To address these challenges, a ground-breaking study was conducted using a cooled copper backing plate to adjust the process temperatures and investigate the influence of the temperature on FSC stability. The results of the study showed that the cooled copper backing plate has a significantly higher rate of heat conduction, effectively preventing the processed component from overheating and ensuring that the process maintains its stationarity. When using the steel backing plate, only one combination of process parameters (a rotation speed of 450 rev/min and a traverse speed of 71 mm/min) yielded satisfactory results. Moreover, the use of the cooled copper backing plate allowed for a wider range of process parameters to be employed, resulting in sub-surface channels with higher quality and fewer defects. The 710/71 parameters combination resulted in a lower heat input, while the 900/45 parameters set produced channels with a more rectangular geometry. A rotation speed of 900 rev/min and a traverse speed of 45 mm/min have been shown to be the best choice. This innovative approach to FSC technology represents a major step forward in solid-state manufacturing, envisaging new possibilities for producing longer sub-surface channels with superior quality and greater efficiency.Highlights• Conducting the FSC process at low temperature has improved its stability.• The use of a cooled copper backing plate enabled a broader range of FSC process parameters.• Longer and stabler leak-free sub-surface channels have been produced in aluminium alloys.Graphical