Control of humping phenomenon and analyzing mechanical properties of Al–Si wire-arc additive manufacturing fabricated samples using cold metal transfer process

Author(s):  
Yashwant Koli ◽  
N Yuvaraj ◽  
Aravindan Sivanandam ◽  
Vipin

Nowadays, rapid prototyping is an emerging trend that is followed by industries and auto sector on a large scale which produces intricate geometrical shapes for industrial applications. The wire arc additive manufacturing (WAAM) technique produces large scale industrial products which having intricate geometrical shapes, which is fabricated by layer by layer metal deposition. In this paper, the CMT technique is used to fabricate single-walled WAAM samples. CMT has a high deposition rate, lower thermal heat input and high cladding efficiency characteristics. Humping is a common defect encountered in the WAAM method which not only deteriorates the bead geometry/weld aesthetics but also limits the positional capability in the process. Humping defect also plays a vital role in the reduction of hardness and tensile strength of the fabricated WAAM sample. The humping defect can be controlled by using low heat input parameters which ultimately improves the mechanical properties of WAAM samples. Two types of path planning directions namely uni-directional and bi-directional are adopted in this paper. Results show that the optimum WAAM sample can be achieved by adopting a bi-directional strategy and operating with lower heat input process parameters. This avoids both material wastage and humping defect of the fabricated samples.

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2671 ◽  
Author(s):  
Maximilian Gierth ◽  
Philipp Henckell ◽  
Yarop Ali ◽  
Jonas Scholl ◽  
Jean Pierre Bergmann

Large-scale aluminum parts are used in aerospace and automotive industries, due to excellent strength, light weight, and the good corrosion resistance of the material. Additive manufacturing processes enable both cost and time savings in the context of component manufacturing. Thereby, wire arc additive manufacturing (WAAM) is particularly suitable for the production of large volume parts due to deposition rates in the range of kilograms per hour. Challenges during the manufacturing process of aluminum alloys, such as porosity or poor mechanical properties, can be overcome by using arc technologies with adaptable energy input. In this study, WAAM of AlMg5Mn alloy was systematically investigated by using the gas metal arc welding (GMAW) process. Herein, correlations between the energy input and the resulting temperature–time-regimes show the effect on resulting microstructure, weld seam irregularities and the mechanical properties of additively manufactured aluminum parts. Therefore, multilayer walls were built layer wise using the cold metal transfer (CMT) process including conventional CMT, CMT advanced and CMT pulse advanced arc modes. These processing strategies were analyzed by means of energy input, whereby the geometrical features of the layers could be controlled as well as the porosity to area portion to below 1% in the WAAM parts. Furthermore, the investigations show the that mechanical properties like tensile strength and material hardness can be adapted throughout the energy input per unit length significantly.


2020 ◽  
Vol 34 (22n24) ◽  
pp. 2040154
Author(s):  
Van Thao Le ◽  
Tien Long Banh ◽  
Duc Toan Nguyen ◽  
Van Tao Le

Wire arc additive manufacturing (WAAM) has received much attention for manufacturing metal parts with medium and large dimensions because of its high deposition rate and low production costs. In this study, the effects of the heat input on the microstructure formation of thin-wall low-carbon steel parts built by a WAAM process were addressed. The mechanical properties of built materials were also studied. The results indicate that the heat input significantly influences on the shape of built thin walls, but has slight effects on the microstructure evolution of built materials. The WAAM thin-wall low-carbon steel presents suitable microstructures and good tensile strengths (YS: 320 – 362 MPa, UTS: 429 – 479 MPa) that are adequate with industrial applications.


Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
Chengxun Zhang ◽  
Zhijun Qiu ◽  
Hanliang Zhu ◽  
Zhiyang Wang ◽  
Ondrej Muránsky ◽  
...  

Relatively high heat input and heat accumulation are treated as critical challenges to affect the qualities and performances of components fabricated by wire arc additive manufacturing (WAAM). In this study, various heat inputs, namely 276, 552 and 828 J/mm, were performed to fabricate three thin-wall Inconel 625 structures by cold metal transfer (CMT)-based WAAM, respectively, and active interpass cooling was conducted to limit heat accumulation. The macrostructure, microstructure and mechanical properties of the produced components by CMT were investigated. It was found that the increased heat input can deteriorate surface roughness, and the size of dendrite arm spacing increases with increasing heat input, thus leading to the deterioration of mechanical properties. Lower heat input and application of active interpass cooling can be an effective method to refine microstructure and reduce anisotropy. This study enhances the understanding of interpass temperature control and the effectiveness of heat inputs for Inconel 625 alloy by WAAM. It also provides a valuable in situ process for microstructure and mechanical properties’ refinement of WAAM-fabricated alloys and the control of heat accumulation for the fabrication of large-sized structures for future practical applications.


2020 ◽  
Vol 65 (3) ◽  
pp. 125-136
Author(s):  
Yildiz Suat ◽  
Baris Koc ◽  
Oguzhan Yilmaz

Wire arc additive manufacturing (WAAM) which is literally based on continuously fed material deposition type of welding processes such as metal inert gas (MIG), tungsten inert gas (TIG) and plasma welding, is a variant of additive manufacturing technologies. WAAM steps forward with its high deposition rate and low equipment cost as compared to the powder feed and laser/electron beam heated processes among various additive manufacturing processes. In this work, sample parts made of low allow high strength steel (ER120S-G) was additively manufactured via WAAM method using robotic cold metal transfer technology (CMT). The process parameters and building strategies were investigated and correlated with the geometrical, metallurgical and mechanical properties on the produced wall geometries. The results obtained from the thin wall sample parts have showed that with increasing heat input, mechanical properties decreases, since higher heat accumulation and lower cooling rate increases the grain size. The tensile tests results have showed that casting steel (G24Mn6+QT2) mechanical properties which requires 500 MPa yield strength can be compared to with as build WAAM process having 640 MPa yield strength. Tensile strength were fulfilled for S690Q and yield strength is very close to the reference value.


Author(s):  
Moosa Zahid ◽  
Khizar Hai ◽  
Mujtaba Khan ◽  
Ahmed Shekha ◽  
Salman Pervaiz ◽  
...  

Abstract Because of the flexible nature of 3D printing and additive manufacturing technology, manufacturing sector has been revolutionized. There is a possibility to manufacture different intricate geometrics that cannot be produced through conventional processes previously. The conventional design concepts such as design for manufacture (DFM) and design for assembly (DFA) have been modified and simplified. Wire arc additive manufacturing (WAAM) has emerged as one of the leading additive manufacturing (AM) processes due to its high deposition rate and economic feasibility. A lot of progress has been made to understand and improve this process and the mechanical properties associated with the fabricated parts. It is specifically cheaper to print large-scale metallic components using WAAM. This paper gives a thorough review of the work that has been done on WAAM by comparing different technological variants of WAAM, which include Metal Inert Gas (MIG), Tungsten Inert Gas (TIG) and Plasma Arc Welding (PAW). The study also discusses the mechanical properties of the fabricated components using different metals, the defects and challenges the process faces today and how they can be reduced. In the end the study also provides overview of WAAM applications in some of the industrial sectors such as construction, automotive, and structural etc.


Crystals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 689
Author(s):  
Trunal Bhujangrao ◽  
Fernando Veiga ◽  
Alfredo Suárez ◽  
Edurne Iriondo ◽  
Franck Girot Mata

Wire Arc Additive Manufacturing (WAAM) is one of the most appropriate additive manufacturing techniques for producing large-scale metal components with a high deposition rate and low cost. Recently, the manufacture of nickel-based alloy (IN718) using WAAM technology has received increased attention due to its wide application in industry. However, insufficient information is available on the mechanical properties of WAAM IN718 alloy, for example in high-temperature testing. In this paper, the mechanical properties of IN718 specimens manufactured by the WAAM technique have been investigated by tensile tests and hardness measurements. The specific comparison is also made with the wrought IN718 alloy, while the microstructure was assessed by scanning electron microscopy and X-ray diffraction analysis. Fractographic studies were carried out on the specimens to understand the fracture behavior. It was shown that the yield strength and hardness of WAAM IN718 alloy is higher than that of the wrought alloy IN718, while the ultimate tensile strength of the WAAM alloys is difficult to assess at lower temperatures. The microstructure analysis shows the presence of precipitates (laves phase) in WAAM IN718 alloy. Finally, the effect of precipitation on the mechanical properties of the WAAM IN718 alloy was discussed in detail.


Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 513
Author(s):  
Jae Won Kim ◽  
Jae-Deuk Kim ◽  
Jooyoung Cheon ◽  
Changwook Ji

This study observed the effect of filler metal type on mechanical properties of NAB (NiAl-bronze) material fabricated using wire arc additive manufacturing (WAAM) technology. The selection of filler metal type is must consider the field condition, mechanical properties required by customers, and economics. This study analyzed the bead shape for representative two kind of filler metal types use to maintenance and fabricated a two-dimensional bulk NAB material. The cold metal transfer (CMT) mode of gas metal arc welding (GMAW) was used. For a comparison of mechanical properties, the study obtained three specimens per welding direction from the fabricated bulk NAB material. In the tensile test, the NAB material deposited using filler metal wire A showed higher tensile strength and lower elongation (approx. +71 MPa yield strength, +107.1 MPa ultimate tensile strength, −12.4% elongation) than that deposited with filler metal wire B. The reason is that, a mixture of tangled fine α platelets and dense lamellar eutectoid α + κIII structure with β´ phases was observed in the wall made with filler metal wire A. On the other hand, the wall made with filler metal wire B was dominated by coarse α phases and lamellar eutectoid α + κIII structure in between.


2021 ◽  
Author(s):  
Ashish Kulkarni ◽  
Prahar M. Bhatt ◽  
Alec Kanyuck ◽  
Satyandra K. Gupta

Abstract Robotic Wire Arc Additive Manufacturing (WAAM) is the layer-by-layer deposition of molten metal to build a three-dimensional part. In this process, the fed metal wire is melted using an electric arc as a heat source. The process is sensitive to the arc conditions, such as arc length. While building WAAM parts, the metal beads overlap at corners causing material accumulation. Material accumulation is undesirable as it leads to uneven build height and process failures caused by arc length variation. This paper introduces a deposition speed regulation scheme to avoid the corner accumulation problem and build parts with uniform build height. The regulated speed has a complex relationship with the corner angle, bead geometry, and molten metal dynamics. So we need to train a model that can predict suitable speed regulations for corner angles encountered while building the part. We develop an unsupervised learning technique to characterize the uniformity of the bead profile of a WAAM built layer and check for anomalous bead profiles. We train a model using these results that can predict suitable speed regulation parameters for different corner angles. We test this model by building a WAAM part using our speed regulation scheme and validate if the built part has uniform build height and reduced corner defects.


Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1610 ◽  
Author(s):  
Paulo J. Morais ◽  
Bianca Gomes ◽  
Pedro Santos ◽  
Manuel Gomes ◽  
Rudolf Gradinger ◽  
...  

Ever-increasing demands of industrial manufacturing regarding mechanical properties require the development of novel alloys designed towards the respective manufacturing process. Here, we consider wire arc additive manufacturing. To this end, Al alloys with additions of Zn, Mg and Cu have been designed considering the requirements of good mechanical properties and limited hot cracking susceptibility. The samples were produced using the cold metal transfer pulse advanced (CMT-PADV) technique, known for its ability to produce lower porosity parts with smaller grain size. After material simulations to determine the optimal heat treatment, the samples were solution heat treated, quenched and aged to enhance their mechanical performance. Chemical analysis, mechanical properties and microstructure evolution were evaluated using optical light microscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray fluorescence analysis and X-ray radiography, as well as tensile, fatigue and hardness tests. The objective of this research was to evaluate in detail the mechanical properties and microstructure of the newly designed high-performance Al–Zn-based alloy before and after ageing heat treatment. The only defects found in the parts built under optimised conditions were small dispersed porosities, without any visible cracks or lack of fusion. Furthermore, the mechanical properties are superior to those of commercial 7xxx alloys and remarkably independent of the testing direction (parallel or perpendicular to the deposit beads). The presented analyses are very promising regarding additive manufacturing of high-strength aluminium alloys.


Author(s):  
Yang Xie ◽  
Haiou Zhang ◽  
Fei Zhou

Additive manufacturing (AM), or 3D printing, is drawing considerable contemporary interest due to its characteristics of high material utilization, great flexibility in product design, and inherent moldless process. Arc-based AM (AAM) is a promising AM method with high deposition rate and favorable buildup quality. Components made by AAM are fabricated through superimposed weld beads deposited from metal wire. Unlike laser-based additive manufacturing, AAM is more difficult to control. Because of the large energy input of the energy source and the liquidity of the melting metal material, bottleneck problems like shrinkage porosity, cracking, residual stresses, and deformation occur. Resultant poor geometrical accuracy and mechanical property keep AAM from industrial application. Especially in the aerospace industry, structural and mechanical property specifications are stringent and critical. This paper presents a novel hybrid manufacturing method by using hot-rolling process to assist the arc welding to solve the above problems. Initially, a miniature metamorphic rolling mechanism (MRM) was developed using metamorphic mechanism theory. Configuration and topology of the MRM can change according to the feature of the components to roll the top and lateral surfaces of the bead. Subsequently, three single-pass multilayer walls were built, respectively, for comparison. The rolled results show significant improvement in geometrical accuracy of the built features. Tensile test results demonstrate improvement in mechanical properties. The improved mechanical properties of rolled specimens are superior to wrought material in travel direction. Microstructure comparisons indicate columnar grains observed in vertical direction and fusion zones were suppressed. Eventually, fabrication of a large-scale aerospace component validates the feasibility of industry application for the hybrid manufacturing technology.


Sign in / Sign up

Export Citation Format

Share Document