Weld Deposits Research Articles

Study on the Arc Additive Manufacturing Process and Mechanical Properties of Inconel 625 Nickel-Based Alloy Bulk

_ The melt-inert gas-shielded arc additive manufacturing experiment of Inconel 625 nickel-based alloy bulk was carried out. The influence of current mode, current, travel speed, weld bead spacing, deposition path, and arc length on the formation of overlapping weld beads was studied. The incomplete fusion near the bottom weld toe of adjacent weld beads was the main defect. The optimized parameters for bulk additive manufacturing obtained from the experiment were as follows: pulse current of 70 A, travel speed of 200 mm/min, weld bead spacing of 3 mm, dry extension of 10 mm, continuous deposition, and arc length of 1 mm. Due to the thermal influence during the deposition of adjacent weld beads, directional grains were formed inside the weld bead and at the boundary with adjacent weld beads. However, the direction of grain growth was not uniform throughout the entire weld bead, and a consistent texture of the entire weld bead was not formed. The tensile strengths of the specimens in the X, Y, and Z directions were 858.5, 838.7, and 827.2 MPa, respectively, and the fracture elongations were 53.3%, 37.6%, and 42.1%, respectively. The strength in the Z direction, which is the vertical direction, was the lowest. Keywords arc additive manufacturing; nickel-based alloy; incomplete fusion; texture

Study of welding deposition performance in changing parameters (welding speed and direction) in hard coating application in sugarcane mills using the FCAW process with a focus on sustainable manufacturing

Being one of the main sources of waste generation from welding processes, filler metal splashes are a source of waste generation that promotes environmental impacts due to their chemical compositions. Actions that converge towards reducing waste, in addition to mitigating environmental impacts, also represent a significant contribution to reducing costs inherent to welding processes. Actions aimed at reducing waste and costs contribute significantly to sustainable production. In this context, a study is proposed that analyzes welding spatter as a contaminating residue and loss of financial resources. Therefore, the objective of this study is to analyze the application of hard coating using the FCAW (Flux-Cored Are Welding) process on shafts in sugar and alcohol plants. The objective is to study the influence of the coating application speed parameter associated with the direction of rotation (welding direction) on the Deposition Yield. As proposed in this study, using welding speeds of 6, 10 and 13.6 m/min with alternating rotation directions (clockwise and counterclockwise), the Deposition Yield was calculated for the 6 situations. The results showed an improvement in performance when 6 m/min and clockwise were combined. This improvement results in savings of approximately R$6.7 million per year and would avoid the generation of 385 tons of hazardous materials in Brazil. These results contribute to more sustainable production.

Laser hot-wire cladded gear preforms for the tailored forming process chain

The local adaptation of a component’s properties through deposition welding in combination with subsequent forming is known as Tailored Forming. By utilizing laser hot-wire cladding, semi-finished products that are later formed into bevel gears are cladded with one or more materials before the hybrid preforms are formed by a die forging process. This publication deals with the layer distribution and the strategy of the deposition welding process of the wire materials X45CrSi9-3 and X2CrNiMo19-12 on a substrate of C22.8. The forming results are analyzed with regard to the layer distribution as well as the microstructure and hardness after welding and forming. The paper will show that the microstructure in the X45CrSi9-3 areas is martensitic after both process steps, which is supported by hardness values of up to 700 HV.

A universal convolutional neural network for the pixel-level detection and monitoring of weld beads

In weld-based manufacturing processes such as welding and metal deposition additive manufacturing (AM), the weld bead is a direct indicator of manufacturing quality. For example, the geometry of the weld bead was optimized to a net shape which outperformed conventional geometries. Automatic monitoring of weld bead is thus of prime importance for welding process control and quality assurance. This paper develops a general-purpose convolutional neural network (CNN) for pixel-level detection and monitoring of beads, regardless of welding materials, machine, manufacturing conditions, etc. To achieve the generality, we collected a great variety of welding images containing 2677 single-line beads from 231 research articles, followed by pixel-wise hand-annotation. Consequently, the trained CNN can recognize different beads from various backgrounds at a pixel level. Case studies show that compared to the image-level classification in prior research, its pixel-level labeling permits real-time, complete characterization of weld beads (e.g., detailed morphology, discontinuity, spatter, and uniformity) for more informed process control. This research represents a significant step towards developing a truly human-like monitoring system with low-level scene understanding ability and general applicability.

Optimization of welding parameters on weld deposits area in pulsed gas metal arc welding

This paper presents a methodology for optimising pulsed gas metal arc welding parameters on Stainless Steel GRADE 410. Most sectors favour the economic welding technique for its favourable outcomes, such as enhanced strength and reduced corrosion. Compared to conventional welding methods, pulsed gas metal arc welding has the advantage of reducing current consumption and increasing the rate at which metal is deposited. An optimisation technique is employed to forecast the weld bead's accurate geometry, penetration depth, and reinforcement height, considering the welding input parameters such as welding speed, current rate, and frequency level. The Taguchi technique uses experimental analysis by considering input and output parameters. A multiple regression analysis model has been developed for SS Grade 410 Stainless steel to determine the bead geometry's correctness.

Investigation of laser wire bonding for the fabrication of tensegrity structures

Tensegrity structures are structures in which elements stabilize each other by bearing compressive or tensile loads. They have a high potential for lightweight design. As structures with tensile loads, wires can be used that are connected to other structures using a laser bonding process. Investigations of bonding a mild steel wire with a diameter of 1 mm onto a flat substrate have been conducted using a coaxial deposition welding head. The influence of the parameters focus position, laser power, wire feed rate and bonding processing time has been investigated regarding the bonding quality. A process window for a stable process and a sufficient bond of wire and substrate was determined. The laser intensity and stickout length have a significant influence on the bonding. High intensities and stickout lengths lead to wire burn back and no bond with the substrate while wire backup occurred at low intensities and stickout lengths.

Comparison of Wear Resistance of Overlay Welded Layers and Thermal Sprayed Coatings in Real Conditions.

Tribological tests in real conditions enable obtaining full data on the life of interacting machine parts. This article presents the results of operational tests on the elements of the support ring guidance system in a vertical ball-race mill. The guide and active armour operate under abrasive wear conditions with moderate-impact loads. The wear resistance of elements with overlay welding layers deposited with flux cored wire with a structure of high-alloy chrome cast iron and with a coating flame-sprayed with nickel-based powder was compared. The wear intensity of the overlay weld deposits was much lower than that of the sprayed coatings. The scope of this study also included the analysis of the chemical and phase composition, macro- and microscopic metallographic examinations, and the measurement of the hardness of the deposited layers and coatings.

Expanding the Technological Possibilities of Multilayer Micro-Plasma Powder Deposition Process by Optimizing the Quality and Composition of Process Gases

Introduction. Mastering the micro-plasma powder deposition (MPWD) technology for refurbishing parts of nickel-based super alloy aircraft gas turbine engine (GTE) has been remaining a relevant task of the Ukrainian air craft industry for, at least, 15 last years.Problem Statement. MPWD or subsequent heat treatment of GTE parts made of nickel-based super alloy after long-term operating hours, with high γ'-phase content, might reveal increased cracking susceptibility. The search for ways to optimize the welding deposition technology has shown the necessity to scrutinize the positive technological effect of rational choice of the quality and content of process (shielding, plasma and transporting) gases.Purpose. To study the effect of process gas content on the heat source parameters, the conditions of the formation of deposited metal and its quality.Material and Methods. Comparative study of the micro-plasma (PPS04 plasmatron, UPNS-304M welding machine) and TIG (VSVU-315 power source) arc heat parameters depending on welding current and process gas has been conducted by the conventional flow calorimetry technology. Comparative estimation of the total work piece heat input parameters has been made based on the previously developed methodology with registering the welding current parameters based on m-DAQ14 analog-to-digital converter (ADC).Results. The comparative research during MPWD of sample parts has shown that the content and quality of process gases can significantly (up to 2.5 times) affect the amount of heat transferred into the work piece and, respectively, the possibility to provide the technological strength of “base-deposited metal” welded joint.Conclusions. The industrial MPWD process optimization by the criteria of work piece heat input parameters, technological strength of “base-deposited metal” welded joint and filler powder consumption,by means of increasing argon (plasma and transporting gas) quality by other gases impurities content and switch to 90% Ar + 10% Н2 argonhydrogen mixture shielding gas has been established to be promising and expedient way to solve the problem.

Using fiber or rod—The influence of different filler materials during CO2 laser welding of quartz glass

Welding of quartz glass is still mainly carried out with gas torches and manually by glass specialists. The use of gas torches is highly energy inefficient as much heat energy is released around the component and into the environment. In addition, the manual process can result in inhomogeneous welds. An automated laser process would make quartz glass welding more energy-efficient and repeatable and address the growing shortage of skilled labor. In this study, quartz glass plates up to 4.5 mm in thickness are welded together at an angle of 125° to each other using a fiber or rod as the filler material. Glass thickness and angle were selected based on a project-specific application. The aim is to achieve a homogeneous weld with as few defects as possible using a lateral fiber- or rod-based deposition welding process. The main challenge is to achieve the melting of the filler material at the bottom contact point of the two glasses so that no air inclusions occur. A 400 μm fiber and a 1 mm rod are investigated as filler materials. The advantage of the fiber compared to the rod is that the contact point of the glasses is easier to reach and bond during the welding process. Due to the large gap between the glass fibers compared to the fiber diameter, a high fiber feed rate is required to fill the V-gap with the viscous glass material. The disadvantage is that the fiber is subjected to high pressure when digging into the melt, which can lead to fiber breakage. In addition, there is a high consumption of filling material. Adjustable and relevant process parameters include the ratio between substrate and fiber feed, the laser power, the spot diameter, and the process gas pressure. The fabricated samples are analyzed using optical and laser confocal microscopy.

Development of swing arc narrow gap GMAW process assisted by swaying wire

In order to further raise narrow gap welding efficiency while improving weld formation, a swing arc narrow gap GMAW process assisted by swaying wire is developed. This process swings the arc to increase groove sidewall penetration, and simultaneously adds a swaying wire to raise the welding deposition rate as well as modify the weld shape. The present work realizes a digital synchronous swaying control between the swing arc and the additional wire on the basis of kinematic modeling, and analyzes the characteristics of arc linear energy distribution in the groove. Arc behaviors, weld formation, and additional wire melting rate are then investigated for the cold wire assisted process. The reduction rates of weld layer number and welding time are also particularly proposed to evaluate the welding efficiency. Experimental results show that the developed process stabilizes the swing arc by attracting the arc to heat the additional wire in synchronous swaying, and yields good welds of sufficient penetrations and indistinctively-changed thickness even at fast feeding rates of the cold wire. Furthermore, the weld layer number and the welding time decrease respectively by ∼26% and ∼54% at most due to a 120% increase in the deposition rate, achieving a high-efficiency and high-quality narrow gap arc welding.

A Study on the Efficient Method of Underwater Welding Education for Commercial Diver

Although the requirements of underwater welding has been increasing in the marine field, limited studies have been conducted on the systematic approaches for underwater welding education. The present study was conducted to provide baseline data to understand the educational underwater welding process for commercial diving candidates. For this, optimal welding parameters for underwater were configured, experimental welding dives were conducted, and weld coupons were inspected and analyzed.</br>The results of this study can be summarized as follows respective weld passes. In the root pass, the insufficient weld deposit sizes owing to the fast weld speed were the main defects. In the second pass, non-paralleled beads and insufficient weld convexity were the main defects. In the third pass, incomplete deposit between the beads and the unplaned weld surface were the main defects. Finally, macro-etching test revealed incomplete penetration, slag inclusion, undersize of weld and unplaned weld profile.</br>The aforementioned weld defects must be reduced for beginner welder divers, selecting welding parameters such as suitable amperage, accurate work angle, and weld speed as the main variables.

High‐performance welding for safety‐relevant applications

AbstractLaser deposition welding helps to speed up the repair process and reduces costs. An important component for this is the new tracing technology from Laservorm, which records at exactly which point of the component which parameters have had what effect.

Influence of shielding gas coverage during laser hot-wire cladding with high carbon steel

In contrast to conventional components made from a single material, hybrid multi-material components allow the production of load-adapted parts with different materials in different structural and functional areas. Hardenable and forgeable steels with a high carbon content are suitable for increasing fatigue and wear resistance and thus an extension of component life. However, materials with an equivalent carbon content of more than 0.6 are considered difficult to weld due to their tendency to crack. This study investigates the influence of the shielding gas coverage on the laser hot-wire cladding process with high carbon cladding material AISI 52100. For this reason, welding tests were carried out with different parameter combinations in a process chamber flooded with argon. The oxygen content in the chamber was less than 500 ppm during the welding process. The claddings welded in the process chamber are compared to the claddings welded in a previous investigation with a commercial shielding gas nozzle for laser deposition welding with wire. The tests conducted showed reduced pore formation and very little sparking. By using a process chamber, the average degree of dilution was reduced from 16.9% to 8.5% and burn-off of alloying elements was reduced. In most cases, high hardness values of 700 HV0.1 to 850 HV0.1 were achieved. The use of the process chamber demonstrates that the shielding gas coverage and therefore the remaining oxygen content have a high influence on the process stability and seam quality when welding high carbon steel. Such a considerable effect has not yet been observed with other commercially available cladding steels.

High‐performance welding for safety‐relevant applications

PhotonicsViewsVolume 20, Issue 3 p. 96-96 PreviewsFree Access High-performance welding for safety-relevant applications Deposition welding with reproducible, predictable quality First published: 20 June 2023 https://doi.org/10.1002/phvs.202370321AboutPDF ToolsExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL No abstract is available for this article. Volume20, Issue3June/July 2023Pages 96-96 RelatedInformation

Surface Modified Optical Fiber Fabry–Perot Cavity Pressure Sensor With Carbon Film

By the method of pulsed laser deposition of a Ni/C bilayer precursor films and annealing in air, amorphous carbon films were prepared on the surface of the capillary used for fabrication of optical fiber Fabry-Perot (FP) cavity pressure sensors. The surface morphologies of the coated and annealed carbon films were investigated through scanning electron microscopy. The images reveal that surface modification smoothes the irregular particles on the capillary surface and releases the stress induced by carbon and nickel deposition and oxy-hydrogen flame welding. Performance tests showed that the surface modified pressure sensors have good linearity for pressure response and the cavity length variations during the full cycle of pressure change is within 31 nm. Furthermore, thanks to the introduction of carbon films, the long-term stability of the cavity length can be kept within 10 nm during the tested 150 days.

Comparison of Weld Built-up by FCAW and MIG Welding on Damaged Low Cr-Mo Alloy Steel Tube in Boiler Application

In boiler application low Cr-Mo tubes are being used and in manufacturing or working these tubes are getting damaged. ASTM and ASME BPVC (Boiler Pressure vessel code is allowing wall thinning of tubes by 10%. Any damage more than 10% of wall thickness is causing rejection of Tube. As ASTM and ASME has provision for weld build-up on defected or damaged portion of Boiler Tubes, hence I am going to compare two welding process for the weld built-up on low Cr-Mo alloy steel tubes. In current practice the damaged tubes are being scrapped in boiler manufacturing as well as in running boilers. After this demonstration we can compare mechanical Properties of reworked tubes with original one. The Two methods adopted are MIG Welding and FCAW. Metal Inert Gas (MIG) welding is known for high deposition welding technique will minimum defect possibility. Flux Cored Arc Welding also has high weld deposition rate with minimum defect possibility.

Effect of the Weld Deposit Thickness on the Impact Strength of Heat-Affected Zone of the Welded Joint

The methodology has been developed to show the functional connection of the impact strength of the heat-affected zone metal of welded joints with weld deposit thickness and, accordingly, with the consumption of welding materials during electric arc welding while constructing and repairing various metal structures and pipeline systems operating in conditions of low climatic temperatures. To reach the objective of the paper, rational intervals of cooling rates of the HAZ metal during welding low-alloy pipe steels were used, and the calculated dependences from the existing works were modified. The methodology allows increasing cold resistance of welded joints of steels of mass use by regulating the weld deposit thickness and welding consumables during electric arc welding while constructing and repairing various metal structures and pipeline systems operating in extreme conditions of the North.

Development of a Thermal Model of Welding by the Finite Element Method in Software "Bazis"

The paper presents a model and an algorithm for calculating the operational properties of a metal and a structure after its assembly-welding. The model is based on the equations of non-stationary thermal conductivity and mechanical equilibrium, as well as the analysis of structural-phase transformations using thermokinetic diagrams. It is implemented in the original BAZIS software package. Validation of software was carried out when calculating thermal fields and deformations as applied to arc welding, arc deposition, and laser welding of standard joints.

The Application of Grooveless Remelt Deposit Welding to the Joining of Large-Caliber Thin-Walled Projectile to Guide Band

This paper introduces the research on guide band welding in China and other countries, analyzes the characteristics of guide bands produced by remelt deposit welding and the application of the welding process to the joining between thin-walled submunition-based projectiles with a large caliber and launched by a howitzer. In addition, this paper raises the performance testing requirements for the grooveless remelt deposit welding process.

Linear Friction Welding of Abrasion Resistant CPM 15V Tool Steel to an Alloyed Carbon Shovel-Tooth Steel

Alloyed carbon steels used in ground engaging tools (GETs), such as shovel-teeth, can withstand high working loads, but their wear resistance is inadequate for abrasive operations in the mining industry. Different approaches to engineer protective surfaces on GETs for improving wear resistance have been developed over the years, but the effectiveness of the applied abrasive resistance layer has been limited by the maximum thickness that can be realized reliably. Considering wear requirements for GETs to reach end-of-life without requiring unscheduled maintenance for after-failure repairs, a minimum thickness of 25 mm has been postulated for the abrasive resistance surface layer, which is roughly four times greater than the thickness of overlays currently manufacturable by weld deposition technologies. Thus, in this study, a novel approach for conceiving thick abrasive surface protection layers—that are unlimited in thickness—on GETs is presented. The method involves applying solid-state linear friction welding and was demonstrated to be feasible for joining abrasive-resistant CPM 15V tool steel to an alloyed carbon steel (extracted from a shovel-tooth). After welding, the integrity of the joints was examined microscopically using optical and scanning electron microscopy to understand the microstructural characteristics, as well as through microhardness and tensile testing to evaluate the performance. A high frequency welding condition was identified that provided integral bonding (i.e., without voids and cracking) at the interface between the CPM 15V tool steel and alloyed carbon shovel-tooth steel. In the as-welded condition, the measured hardness profiles across the joints showed minor softening of both base materials in the heat-affected zone just adjacent to the weld center; this was attributed to over aging of the tempered martensite structures of CPM 15V tool steel and alloyed carbon shovel-tooth steel. The maximum tensile strength of the joint (553 MPa) provides evidence for the viability of linear friction welding technology for joining protective surface materials on GETs.