Steel Filler Research Articles

Comparative analysis of microstructural and nanomechanical characteristics of MIG and TIG-MIG hybrid welded inconel 718 and AISI 316 with steel and inconel fillers

The joining of Austenitic Stainless Steel (AISI 316) and Inconel (IN718) was carried out using Metal Inert Gas (MIG) welding and hybrid TIG-MIG welding with Inconel (IN625) and steel fillers. The resulting weldments were examined for their microstructural and compositional characteristics, elastic modulus, and nano-hardness using optical microscopy, X-ray diffraction, and nanoindentation techniques. The results indicated that the base metal IN718 exhibited higher hardness and elastic modulus compared to AISI 316. Additionally, the formation of the δ-Ni3Nb phase was observed in both MIG and hybrid welding processes using IN625 filler, along with austenitic matrices of Fe and Ni. When steel filler was used, it led to the development of a finer cellular, columnar, and equiaxed dendritic microstructure compared to the IN625 filler. The highest hardness in the heat-affected zone (HAZ) of IN718 was observed in hybrid welding with the steel filler, which was 7% and 5% higher compared to MIG welding with IN625 and steel fillers, respectively. Moreover, the maximum hardness in the fusion zone (FZ) of 4.55 GPa was achieved in MIG welding with the steel filler, which was 36% and 69% higher compared to hybrid welding with steel and IN625 fillers, respectively. The hardness varied between 2.74 GPa and 3.62 GPa in the HAZ of AISI 316 for MIG welding with steel and IN625 fillers, respectively. The elastic modulus was found to be 213 GPa in MIG welding with IN625 filler and 214 GPa in hybrid welding with steel filler. Pile-up behavior was observed around the nanoindents for all weldments obtained in both MIG and hybrid welding using steel and IN625 fillers.

Investigate on dissimilar welding of high-entropy alloy and 310S with various fillers

This study investigates the microstructure and mechanical properties of non-equimolar CoCrFeMoNi high-entropy alloy (HEA) and SUS310S stainless steel dissimilar welds using different filler materials. The dissimilar welding was performed on gas tungsten arc welding with Inconel 82, Inconel 625, and 316L stainless steel fillers. The non-equimolar CoCrFeMoNi HEA is shown effective weldability with these fillers, maintaining distinguished phase stability and structural integrity. Microstructural analysis revealed varied grain morphologies influenced by the heat in the fusion zone and heat-affected zone. Mechanical properties were evaluated through tensile and hardness tests, showing that welds with Inconel 625 filler exhibited superior strength and ductility. The weld hardness value was maintained at 170 HV, with a yield strength of 301 MPa and an ultimate tensile strength of 587 MPa, resulting in a joint efficiency of 106 %.

A new method for joining Incoloy825/X65 composite plate by laser and CMT welding

Incoloy825/X65 composite plate had good application in the submarine transporting pipelines due to combination of the high resistance to Cl− corrosion and preferred mechanical properties. But the enrollment of Fe into Ni layer deteriorated the corrosion resistance in welding the transition layer of composite plate. In view of this, the paper respectively adopted the laser welding on the Ni layer without filler metal and then the swing arc CMT welding with steel filler metal as a transition in order to inhibit the Fe into Ni layer. The results showed the laser welding bead on Ni layer with uniform and fine γ microstructure ensured the better corrosion resistance. The CMT welding controlled the dilution rate under 6 % through optimizing the welding speed and swing frequency of arc. Finally, the tensile strength of transition weld was up to 500 MPa surpassing the base metal of 490 MPa. The clad bead with charge transfer resistance of 756 kΩ·cm2 satisfied general submarine pipeline anti-corrosion requirement.

A Comparison of Sigma Phase Formation in Solubilized Hyper Duplex Stainless Steel and Super Duplex Stainless Steel Filler Metals

This study focuses on the kinetic analysis of sigma phase formation in filler metal wires on Super Duplex Stainless Steel (SDSS) and Hyper Duplex Stainless Steel (HDSS). Precipitation data reveal that in the solubilized microstructure, sigma phase kinetics are more prominent in SDSS. This increased susceptibility is attributed to the greater number of nucleation sites, which is facilitated by the larger interface area/volume and the higher chromium content in the ferrite. The difference in interface area/volume is significantly more influential in determining kinetics than the composition difference, with nucleation sites playing a central role. The sigma phase transformation in both materials was modeled using the JMAK kinetic law. The JMAK plots exhibit a transition in kinetic mechanisms, evolving from discontinuous precipitation to diffusion-controlled growth. In SDSS, the JMAK values indicate “grain boundary nucleation after saturation,” followed by “thickening of large plates.” In contrast, HDSS values point to “grain edge nucleation after saturation,” followed by “thickening of large needles.” The higher kinetics in SDSS are characterized by a smaller nucleation activation energy of 56.4 kJ/mol, in contrast to HDSS's 490.0 kJ/mol. CALPHAD-based data support the JMAK results, aligning with the maximum kinetics temperature of SDSS (875 °C to 925 °C) and HDSS (900 °C to 925 °C). Therefore, the JMAK sigma phase kinetics effectively describe the experimental data and its dual kinetics behavior, even though CALPHAD-based TTT calculations often overestimate sigma formation.

Simulating chemical mixing and molten pool shape in dissimilar welds using thermal fluid dynamics

Estimating the properties of dissimilar metal welded joints made using modern high-energy beam techniques presents significant challenges due to the complex nature of the process. These complexities arise from the different thermal and mechanical properties of the materials involved. The properties of a welded joint are primarily determined by the element mixing and final chemical composition when two dissimilar metals are fused together, or when a dissimilar filler material is used. Hence, a representative model capable of tracking elemental distribution and temperature is essential for accurately estimating the micro-scale and macro-scale mechanical properties of the joint, thus optimising the joining process. In this work, a high-fidelity thermal fluid flow model in the multiComponentlaserbeamFoam computational fluid dynamics (CFD) solver is used to simulate the process of laser beam welding. For this purpose, the joining process of AISI 304 stainless steel with a low alloy steel filler material (G3Si1) is simulated. This framework is rigorously validated with experimental results showing the capabilities of such modelling approach. Different strategies to model the filler and material properties are explored: a stationary filler model, applied through the parent material's thickness, was found to accurately mirror experimental results. This model is then used to study the flow properties, thermocapillary effect, and diffusion on the intermixing of composition, aspects that have not been previously examined in depth. The thermocapillary forces were concluded to be the most significant, dictating the peak composition value, the shape and topology of the molten pool. Diffusion fluxes were found to be negligible and not responsible for the majority of the mixing.

Исследование изменения геометрических параметров образцов, наплавленных методом GMAW при воздействии на электрическую дугу продольного магнитного поля

Introduction. The paper presents the results of research of additive manufacturing process by electric arc with axial feeding of steel filler wire in protective gas environment (GMAW technology) with additional influence of external longitudinal magnetic field on electric arc. Purpose of work: an experimental study of the effect of a longitudinal magnetic field during additive manufacturing by an electric arc with axial feed of filler wire made of structural steels in a protective gas environment on the change in the geometrical characteristics of the layers being surfaced. Research Methods. The manufacturing of specimens was carried out on a 5-axis additive machine based on a CNC machine. Surfacing was carried out in the following modes: voltage 17.5 V; current 55–65 A; wire diameter 1.2 mm; wire material Sv-08G2S; wire feed rate 2,267 mm/min; approximate roll diameter 3.0 mm; roll length 50 mm; number of wires per one roll 312.5 mm; number of layers when surfacing the wall 5; magnet operation mode: alternating current with frequency 50 Hz, voltage 30 V; measured magnetic induction 5.7 mTl; initial height of the magnet above the substrate 10 mm; electrode stickout 10 mm; shielding gas: welding mixture CO2-Ar; gas pressure (flow rate) 0.15 MPa. Results and discussion. The conducted experimental study showed that the effect of longitudinal magnetic field had a statistically significant effect on the change in the dimensions of the singular, namely an increase in the width of the layers being surfaced by 34.1 %, with a calculated significance index close to zero, and a decrease in height by 20.2 %, with a calculated significance index equal to 2.7105. The effect of longitudinal magnetic field had a statistically significant effect on the change of the overall dimensions of the specimens consisting of five layers, namely, the width of the specimens increased by 11.2 % with a calculated significance index of 4.3103, and the height of the specimens decreased by 10.3 % with a calculated significance index of 6.3105. The effect of longitudinal magnetic field had no statistically significant effect on the change of the vertical deviation from straightness for the side walls of the specimens, with a calculated significance index of 0.3277, and had no statistically significant effect on the change of the error of the width of the walls of the specimens, with a significance index of 0.098.

Specification of the optimal gas metal arc welding (GMAW) parameters to enhance the mild steel strength (MS1018)

Arc fusion processes, such as high-efficiency gas metal arc welding (GMAW), have become increasingly prevalent in various industries. To optimize the GMAW parameters and enhance the strength of MS 1018, Monika and Chauhan conducted experiments using the low carbon steel filler wire (ER 70 S6). They used a Taguchi L9 OA (orthogonal array) to generate test data focusing on 3 GMAW parameters such as gas flow rate, arc voltage, and welding current. The performance characteristics considered were tensile strength (TS), weld zone hardness (WZH), and heat-affected zone hardness (HAZH). The effect of GMAW parameters investigated using the S/N (signal-to-noise ratio) transformation of individual test data, which is valid to account for variations observed in repeated tests. By conducting a thorough analysis of variance (ANOVA) on this transformed data, they were able to identify the optimal GMAW parameters for achieving high TS, WZH, and HAZH. Given that HAZH exhibited higher values than WZH, it was evident that TS had the most significant impact on the GMAW process. Consequently, the researchers established empirical relationships for TS, WZH, and HAZH in terms of the GMAW parameters. Their test data aligned reasonably well with the expected range of performance indicators, supporting the validity of their findings. Overall, Monika and Chauhan’s modified Taguchi approach, based on the L9 OA, allowed them to efficiently conduct a limited number of tests while obtaining comprehensive information on the optimal GMAW parameters for enhancing the strength of MS 1018.

Effects of Welding Parameters on Droplet Transfer and Bead Geometry in Laser Welding with Aluminum and Stainless Steel Filler Wires

Laser welding is increasingly used in industries because it allows high production cycle time and single-sided welding, but is characterized by a high sensitivity to joint preparation. By inserting filler wires, the sensitivity to joint preparation can be suppressed. In this study, the effect of welding variables on the bead geometry and melted droplet transfer were investigated. Two wires with different thermal diffusivities and densities were selected: stainless steel (STS) and aluminum (Al) wires. According to the wire feeding angle, the melting area tended to differ between the STS and Al wires. This implied that the wire feeding angle had to consider the absorption rate of the material for the laser wavelength. With an increase in the distance between the wire tip and the substrate, the dominant force acting on the droplet was changed from surface tension to gravity. Therefore, the distance was considered as a major factor in determining the droplet transfer mode. In all cases, the droplet transfer period exhibited relatively small deviation when the wire feeding direction was leading. Furthermore, the focal length effects on droplet transfer were irrelevant.

Mechanical performance of 22SiMn2TiB steel welded with low-transformation-temperature filler wire and stainless steel filler wire

Mechanical performance of 22SiMn2TiB steel welded with low-transformation-temperature filler wire and stainless steel filler wire

Sigma phase kinetics in DSS filler metals: A comparison of sigma phase formation in the as-welded microstructure of super duplex stainless steel and hyper duplex stainless steel

This study investigates and compares the kinetics of sigma phase formation in established Super Duplex Stainless Steel (SDSS) and recently developed Hyper Duplex Stainless Steel (HDSS) filler metal wires. Experimental sigma phase time-temperature-transformation (TTT) maps were developed, revealing nearly equivalent interface area/volume, resulting in similar sigma phase kinetics for 1% volume despite the higher Cr and Mo content in HDSS. However, the growth rate to 5% and 10% sigma phase volumes was slightly higher in HDSS. The sigma phase kinetics in both SDSS and HDSS were analyzed using the exponential Johnson-Mehl-Avrami-Kolmogorov (JMAK) approach based on experimental TTT data. Linearized plots from the JMAK calculations showed a transition in kinetics mechanism from eutectoid decomposition and interface-controlled growth to a diffusion-controlled growth stage in both materials. The higher volumes and morphologies of the sigma phase were found to be diffusion-dependent, mainly occurring during the second kinetics stage. The influence of HDSS's higher Cr and Mo content on the growth rate was observed for these higher volumes. For applications within the 1% sigma phase limit, both wires exhibited equivalent susceptibility to sigma phase formation, regardless of the higher alloying in HDSS.

Evaluation of crane wheels restored by hardfacing two distinct 13Cr-4Ni martensitic stainless steels

Depositing two martensitic stainless steel filler metals with chemically different composition, crane wheels were restored to study the development of mechanical properties and wear resistance. For this purpose, a two-layer clad was deposited using each filler metal through submerged arc welding process. Microstructural evolution shows that solidification modes are different in the hardfaced clads due to the discrepancy in the ratio of chromium equivalent to nickel equivalent (Creq/Nieq). A reduction in Creq/Nieq leads to the enrichment of liquid metal in austenite-promoter elements, resulting in the presence of austenite phase in the matrix, as identified by XRD pattern. Following a post-weld heat treatment in the constant temperature of 500 °C for an hour, apart from the tempered martensite, fresh martensite as a consequence of transforming austenite phase is formed in the matrix. This transformation significantly increases the mean value of microhardness from 360 to 462 HV0.3. Also, uniaxial tensile test shows that the formation of fresh martensite approximately limits the elongation of the clad. The fractography studies show that the fracture mode in both clad is the same and ductile, with embedded carbides in dimples. Tribological behavior of the clads shows that the formation of fresh martensite in the clad results in higher wear resistance, with specific wear rate of 1.8 × 10−5 mm3/Nm at the maximum load. In addition, oxidative wear mechanism is dominant at lower load of 10 N, while the wear mechanism changes at higher load of 60 N to severe plastic deformation.

Relationship between microstructure, and residual strain and stress in stainless steels in-situ alloyed by double-wire arc additive manufacturing (D-WAAM) process

In the field of welding, assembly of thick parts requires the base metal to be chamfered, followed by multipass welding. The process generates thermal, mechanical, and metallurgical phenomena resulting in the formation of residual strains and stresses. Strains must be limited, as they can cause misalignments during welding and leads to geometrical defects. Residual stresses are especially problematic in structural assemblies, as they add to the external stresses applied to the part during service, often reducing its in-service lifetime and increasing the risk of failure.The objective of this study is to use two stainless steel filler metals with different coefficients of thermal expansion (austenitic 304 L and ferritic 430) to reduce residual stresses and strains in the context of deposits produced by the Double-Wire Arc Additive Manufacturing process on 304 L baseplates. To achieve such a goal, the two filler are mixed in various proportions. After deposition and cooling, residual stresses are determined using neutron diffraction and contour method, strains are studied with profilometry. Microstructure is analyzed via EBSD, free dilatometry tests and XRD.We were able to reduce strains and stresses with a three-phase microstructure (austenite, ferrite, and martensite). The part that offers the best compromise (50% 430 - 50% 304 L filler on 304 L baseplate) exhibits a 67% reduction in strain, and stresses are reduced down to 40%, as compared to the 100% 304 L filler on 304 L baseplate part. The results obtained from neutron diffraction and contour method exhibit a close agreement, with a discrepancy standing below 100 MPa.

A benchmark of mechanical properties and operational parameters of different steel filler metals for wire arc additive manufacturing

A benchmark of mechanical properties and operational parameters of different steel filler metals for wire arc additive manufacturing

Use of high ductile mortar mixing method for the enhancement of flexural fracture behaviour of steel filler mortar

The use of steel fillers enhances the flexural behaviour of mortar and concrete. However, it makes it more difficult to disperse them uniformly and coat them firmly in the mortar/concrete with the conventional mixing method while using them at higher content. In this method, steel fillers are generally mixed after the mixing of mortar with a full part of water. In the high ductile mortar mixing method, the viscous mortar was first prepared with the first part of the water and then the steel fillers were mixed. Its workability was increased in the final stage of mixing with the second part of the water. The mixture proportion of the base mortar was similar to that used for the production of the permanent formwork (W/C = 30% and W = 206 kg/m3). The content of steel filler (0, 1.5%, and 2.5%) was by volume of the mortar and it was used as part of the sand. The distribution and coating condition of steel filler was better in the second mixing method. It was made possible due to the strong kneading and lapping action within the viscous mortar. The flexural strength was increased by 28.7% with less variation. It was a 241% increase from that of plain mortar and only a 165% increase was with the conventional mixing method. The high ductile mortar mixing method enhanced the flexural strength, deflection, rigidity, flexural performance, and fracture energy of steel filler mortar more than that of the conventional mixing method. This result contributes to reducing the thickness of permanent steel filler mortar formwork as well as of other structures enabling easier transportation and erection work. Moreover, it also helps to reduce the overall cost of the steel filler mortar structures.

Hardness and Impact Fracture Behavior of Armor Weldment Using Austenitic Stainless Steel Filler

Hardness and Impact Fracture Behavior of Armor Weldment Using Austenitic Stainless Steel Filler

Microstructure, Fractography, and Mechanical Properties of Hardox 500 Steel TIG-Welded Joints by Using Different Filler Weld Wires.

This paper deals with the effects of three low-carbon steel filler metals consisting of ferritic and austenitic phases on the weld joints of the tungsten inert gas (TIG) welding of Hardox 500 steel. The correlation between the microstructure and mechanical properties of the weld joints was investigated. For this purpose, macro and microstructure were examined, and then microhardness, tensile, impact, and fracture toughness tests were carried out to analyze the mechanical properties of joints. The results of optical microscopy (OM) images showed that the weld zones (WZ) of all three welds were composed of different ferritic morphologies, including allotriomorphic ferrite, Widmanstätten ferrite, and acicular ferrite, whereas the morphology of the heat-affected zone (HAZ) showed the various microstructures containing mostly ferrite and pearlite phases. Further, based on mechanical tests, the second filler with ferritic microstructure represented better elongation, yield strength, ultimate tensile strength, impact toughness, and fracture toughness due to having a higher amount of acicular ferrite phase compared to the weld joints concerning the other fillers consisting of austenitic and ferritic-austenitic. However, scanning electron microscopy (SEM) images on the fracture surfaces of the tensile test showed a ductile-type fracture with a large number of deep and shallow voids while on the fracture surfaces resulting from the Charpy impact tests and both ductile and cleavage modes of fracture took place, indicating the initiation and propagation of cracks, respectively. The presence of acicular ferrite as a soft phase that impedes the dislocation pile-up brings about the ductile mode of fracture while inclusions may cause stress concentration, thus producing cleavage surfaces.

Experiment and Simulation Study of the Effect of Fillers on Mechanical Properties of Sustainable Composite

Abstract Natural fiber reinforced polymer matrix composites are gaining increasing attention as engineering materials for advanced applications, including high performance ballistic armor components. This requires superior mechanical properties, such as toughness. Jute fiber reinforced composites are currently being explored as possible advanced engineering materials. Therefore, the objective of this study is to investigate the mechanical characteristics of epoxy composites reinforced with jute fibers and steel fillers. In the present study, three types of the composite of two-way jute carpet and steel fillers were reinforced with epoxy, with different rates of each material.

Microstructure and mechanical properties of gas metal arc welded CoCrFeMnNi joints using a 410 stainless steel filler metal

The use of filler materials during fusion-based welding processes is widely used to regulate and modify the composition of the welded joints aiming at producing a desired microstructure and/or achieving an improvement in its mechanical performance. Welding of high entropy alloys is still a new topic and the impact of different filler materials on the microstructure and mechanical properties is yet unknown. In this work, gas metal arc welding of the CoCrFeMnNi high entropy alloy using 410 stainless steel as a filler wire was performed. The microstructural evolution of the welded joints was evaluated by optical microscopy, scanning electron microscopy aided by electron backscattered diffraction, high energy synchrotron X-ray diffraction and thermodynamic calculations. Meanwhile, the mechanical behavior of the welded joint, as well as the local mechanical response were investigated with microhardness mapping measurements and with non-contact digital image correlation during tensile loading to failure. The weld thermal cycle promoted solid state reactions in the heat affected zone (recovery, recrystallization and grain growth), which impacted the microhardness across the joint. The role of the 410 stainless steel filler material in the solidification path experienced by the fusion zone was evaluated using Scheil-Gulliver calculations, and a good agreement with the experimentally observed phases was observed. Despite the addition of the 410 stainless steel filler was not conducive to an increase in the fusion zone hardness, the associated bead reinforcement promoted an improvement in both the yield and tensile strengths of the joint compared to a similar weld obtained without filler material (355 vs 284 MPa and 641 vs 519 MPa, respectively). This allows to infer that the addition of filler materials for welding high entropy alloys is a viable method for the widespread use of these novel materials. In this work, by coupling microstructure and mechanical property characterization, a correlation between the processing conditions, microstructure and mechanical properties was obtained providing a wider basis for promoting the application of gas metal arc welding of high entropy alloys for industrial applications.

Microstructure and mechanical properties of gas metal arc welded CoCrFeMnNi joints using a 308 stainless steel filler metal

In this paper, gas metal arc welding of a CoCrFeMnNi high entropy alloy was performed using 308 stainless steel filler wire. Electron backscatter diffraction and synchrotron X-ray diffraction were used to determine the microstructural evolution, while microhardness mapping and non-contact digital image correlation were employed to assess the local mechanical response across the welded joints. Further, thermodynamic calculations were implemented to support the understanding of the microstructure evolution. Through a systematic analysis of the microstructure evolution and mechanical properties, it is established a correlation between welding process, microstructure and mechanical properties. Besides, this work lays the foundations for the use of low-cost arc-based welding technologies for successful joining and application of welded joints based on high entropy alloys.

Effect of welding parameters on the mechanical and metallurgical properties of armor steel weldment

The effect of welding parameters on the mechanical and metallurgical properties of armor steel weldment was studied using gas tungsten arc welding process with two filler wires: carbon steel and austenitic stainless-steel filler wires (AWS A5.18 ER 70S-6 and AWS A5.9 ER 307, respectively). The joint configurations were mainly single V and single bevel grooves. Using both AWS A5.18 ER70S-6 carbon steel filler wire and AWS A5.9 ER307, austenitic filler wire for the two joints passed the required tensile strength by the military standard. The joints successfully regained the base metal hardness at a distance of less than 15 mm. The ultimate tensile strength of the joints welded in a single bevel groove is 906 MPa which is higher than the joints welded using a single V groove is 865 MPa. This could be attributed to the increase in dilution percentage with the single bevel joints. Both single V joint and single bevel joints passed the required Charpy V-notch impact test whether using both carbon and stainless-steel wires. The effect of heat input and cooling rate on the mechanical and microstructure of welded joints was studied. The reduction of heat input caused a narrow HAZ with a small reduction in its hardness values with much reduction in the width of softening microstructure zone. SEM observations show that the base metal has a martensitic structure, but the weld metal microstructures depend on the filler: carbon steel or austenitic steel types. Using a single bevel groove with an austenitic steel filler metal, the weld metal shows a martensitic/austenitic microstructure by SEM observation, and this was verified by the Schaeffler diagram which showed a high dilution percentage (about 35% dilution). This resulted in a significant increase in joint strength and a higher weld metal impact resistance.