Ruizhe Wang, Runsheng Li, Guilan Wang, Mingbo Zhang, Jianwu Huang, Hang Lin and Haiou Zhang
Wire and arc additive manufacturing (WAAM) technology-based cold metal transfer (CMT) to produce large aluminum alloy parts has become more and more popular. In WAAM, wire is the…
Abstract
Purpose
Wire and arc additive manufacturing (WAAM) technology-based cold metal transfer (CMT) to produce large aluminum alloy parts has become more and more popular. In WAAM, wire is the only raw material. The purpose of this paper is to study the effect of wire composition on the microstructure and properties of the ZAlCu5MnCdVA alloy deposited by WAAM.
Design/methodology/approach
Two thin-walled ZAlCu5MnCdVA alloys with different wire compositions were prepared by WAAM. The copper contents were 4.7% (Al-4.7Cu) and 5.0% (Al-5.0Cu), respectively. The microstructure, element distribution and evolution of precipitated phases of the two samples were characterized and analyzed by optical microscopy, scanning electron microscopy and transmission electron microscopy. Hardness and tensile properties of samples were tested, and strengthening mechanism was analyzed in detail.
Findings
The results show that grain sizes of Al-4.7Cu and Al-5.0Cu are less than 40 μm. The average mass fraction of Cu in Al matrix and the number of nanometer scale θ'' and θ' phases are the main factors affecting the tensile properties of Al-Cu alloy. Tensile properties of two materials show different characteristics at room temperature and high temperature. Al-5.0Cu is better at room temperature and Al-4.7Cu is better at high temperature. The yield strength (YS), ultimate tensile strength (UTS) and elongation in the x direction of Al-5.0Cu at room temperature are 451 ± 10.2 MPa, 486 ± 10.2 MPa and 9 ± 0.5%, respectively. The YS, UTS and elongation in the x direction of Al-4.7Cu at high temperature are 290 ± 4.5 MPa, 356 ± 7.0 MPa and 13% ± 0.2%, respectively.
Originality/value
Experiments show that the increase of Cu element can improve the properties at room temperature of the ZAlCu5MnCdVA alloy by WAAM, but its properties at high temperature decrease.
Details
Keywords
Xushan Zhao, Yuanxun Wang, Guilan Wang, Runsheng Li and Haiou Zhang
This paper aims to summarize the influence law of hybrid deposited and micro-rolling (HDMR) technology on the shaping strain and residual stress. And the rolling parameters…
Abstract
Purpose
This paper aims to summarize the influence law of hybrid deposited and micro-rolling (HDMR) technology on the shaping strain and residual stress. And the rolling parameters combination was further optimized to guide the actual production.
Design/methodology/approach
This paper proposed a three-dimensional coupled thermo-mechanical model of the HDMR process. The validated model is used to investigate the influences of rolling parameters on stress and plastic strain (the distance between the energy source and roller [De–r], the rolling compression [cr] and the friction coefficient [fr]). The orthogonal optimization of three factors and three levels was carried out. The influence of rolling parameters on the plastic strain and residual stress is analyzed.
Findings
The simulation results show that HDMR technology can effectively increase the shaping strain of the weld bead and reduce the residual tensile stress on the weld bead surface. Furthermore, the influence of rolling parameters on stress and strain is obtained by orthogonal analysis, and the corresponding optimal combination is proposed. Also, the rolling temperature significantly affects the residual stress, and the rolling reduction has a substantial effect on the plastic deformation.
Research limitations/implications
Owing to the choice of research methods, this paper failed to study microstructure evolution.
Originality/value
This paper provides a reference principle for the optimal selection of rolling parameters in HDMR.
Details
Keywords
Qingyong Chen, Guilan Wang, Haiou Zhang and Runsheng Li
The purpose of this paper is to study the influence of different rolling deformation parameters on the morphology, microstructure and mechanical properties of Inconel 718…
Abstract
Purpose
The purpose of this paper is to study the influence of different rolling deformation parameters on the morphology, microstructure and mechanical properties of Inconel 718 superalloy in hybrid plasma arc and micro-rolling (HPAMR) additive manufacturing.
Design/methodology/approach
In this paper, different deformation strains are designed, which are as-deposited, 15% and 30%. Two straight walls are fabricated by HPAMR for each kind of deformation. One wall underwent post-deposition heat treatment, and the other wall is treated without heat treatment. These samples are further investigated to evaluate the effects of deformation on the morphology, microstructure and mechanical properties.
Findings
As compared to as-deposited samples, the morphology can be significantly improved, the generation of defects and microporosity inside the alloy can be suppressed, and finer equiaxed crystals can be obtained with deformation of 30%. With heat treatment and 30% deformation, the Laves phase at the grain boundary is completely disappearing, more γ” and γ' strengthening phase is precipitated in the crystal and the size of the strengthening phase is smaller. Mechanical properties have been significantly improved.
Practical implications
HPAMR technology is used to successfully manufacture Inconel 718 superalloy aero-engine casing.
Originality/value
Compared with plasma arc additive manufacturing, HPAMR technology adds a rolling process, which can effectively improve the morphology of walls, refine internal grains, eliminate defects and microporosity, increase precipitation of strengthening phase and improve mechanical properties. It provides an optional manufacturing method for the integrated manufacturing of Inconel 718 parts.
Details
Keywords
Shangyong Tang, Guilan Wang, Cheng Huang, Runsheng Li, Siyu Zhou and Haiou Zhang
The modeling and optimization of a weld bead in the middle of the weld are often simple, as the forming process is dynamically balanced. However, the arc striking (AS) and arc…
Abstract
Purpose
The modeling and optimization of a weld bead in the middle of the weld are often simple, as the forming process is dynamically balanced. However, the arc striking (AS) and arc extinguishing (AE) areas of weld beads are generally abnormal because the dynamic processes at these areas are unstable. The purpose of this paper is to investigate the abnormal areas of the weld bead with optimization modeling methods in wire and arc additive manufacturing (WAAM).
Design/methodology/approach
A burning-back method was proposed to fill the slanted plane in the AE area. To optimize the welding parameters and obtain the optimal design, a response surface methodology was proposed to build the relationships between the input parameters and response variables.
Findings
The proposed burning-back method could fill the slanted plane in the AE area. Second-order models of abnormal areas were developed and the optimization effects were analyzed. The experimental results indicated that the relationship models at both ends were applicable and preferable for the optimization of weld beads.
Originality/value
In this paper, a burning-back method was proposed to optimize the slanted plane in the AE area. Second-order models of abnormal areas were established. The methods and models were preferable in the optimization of the abnormal areas in WAAM.
Details
Keywords
Jun Wu, Cheng Huang, Zili Li, Runsheng Li, Guilan Wang and Haiou Zhang
Wire and arc additive manufacturing (WAAM) is a widely used advanced manufacturing technology. If the surface defects occurred during welding process cannot be detected and…
Abstract
Purpose
Wire and arc additive manufacturing (WAAM) is a widely used advanced manufacturing technology. If the surface defects occurred during welding process cannot be detected and repaired in time, it will form the internal defects. To address this problem, this study aims to develop an in situ monitoring system for the welding process with a high-dynamic range imaging (HDR) melt pool camera.
Design/methodology/approach
An improved you only look once version 3 (YOLOv3) model was proposed for online surface defects detection and classification. In this paper, improvements were mainly made in the bounding box clustering algorithm, bounding box loss function, classification loss function and network structure.
Findings
The results showed that the improved model outperforms the Faster regions with convolutional neural network features, single shot multibox detector, RetinaNet and YOLOv3 models with mAP value of 98.0% and a recognition rate of 59 frames per second. And it was indicated that the improved YOLOv3 model satisfied the requirements of real-time monitoring well in both efficiency and accuracy.
Originality/value
Experimental results show that the improved YOLOv3 model can solve the problem of poor performance of traditional defect detection models and other deep learning models. And the proposed model can meet the requirements of WAAM quality monitoring.
Details
Keywords
Runsheng Li, Haiou Zhang, Fusheng Dai, Cheng Huang and Guilan Wang
Large-scale aircraft parts usually with many frame features, which consist of intersections. Profile and tensile properties of junctions in wire and arc additive manufacturing…
Abstract
Purpose
Large-scale aircraft parts usually with many frame features, which consist of intersections. Profile and tensile properties of junctions in wire and arc additive manufacturing (WAAM) are significantly affected by path strategies. The purpose of this paper is to propose a novel path strategy for intersections in WAAM and compare it with commonly used ones.
Design/methodology/approach
Three typical intersections including T crossing (TC), square crossing (SC) and arbitrary-angle crossing (AAC) were built up with two commonly used path strategies (parallel and oscillation) and a proposed method named end lateral extension (ELE) which extends the weld track along the crossed direction. A robotic system and cold metal transfer (CMT) process were used to deposit Al-6.3Cu (2319) alloy. The profile of the bead was scanned by laser vision sensor. Tightened ratio (r), inter-layer height increment (Δh) and deviation to the fitting plane (df) are calculated based on the point cloud. Tensile tests were done for all built intersections.
Findings
Comparison to the commonly used path strategies, the proposed ELE method eliminated the tightened defects at the intersection, achieved a more stable inter-layer height increment (Δh) and improved the profile quality with a lower deviation to the fitting plane (df). Tensile tests show that the proposed strategy has exhibited favorable tensile properties.
Originality/value
In this paper, a novel path strategy named ELE is proposed, which provides a new path choice for fabricating intersections by WAAM.
Details
Keywords
Shangyong Tang, Guilan Wang, Hao Song, Runsheng Li and Haiou Zhang
Modeling and control of bead geometry in wire and arc additive manufacturing is significant as it affects the whole manufacturing process. The purpose of this paper is to…
Abstract
Purpose
Modeling and control of bead geometry in wire and arc additive manufacturing is significant as it affects the whole manufacturing process. The purpose of this paper is to establish an efficient model to control the bead geometry with fewer experiments in wire and arc additive manufacturing (WAAM).
Design/methodology/approach
A multi-sensor system is established to monitor the process parameters and measure the bead geometry information. A dynamic parameters experimental method is proposed for rapid modeling without dozens of experiments. A deep learning method is used for bead modeling and control. To adaptively control the bead geometry in real-time, a closed-loop control system was developed based on the bead model and in situ monitoring.
Findings
A series of experiments were conducted to train, test and verify the feasibility of the method and system, and the results showed that the proposed method can build the bead model rapidly with high precision, and the closed-loop system can control the forming geometry adaptively.
Originality/value
The proposed modeling method is novel as the experiment number is reduced. The dynamic parameters experimental method is effective with high precision. The closed-loop control system can control the bead geometry in real-time. The forming accuracy is elevated.
Details
Keywords
Haiou Zhang, Xiangping Wang, Guilan Wang and Yang Zhang
The purpose of this paper is to report a new direct metal manufacturing method which integrates freeform deposition process and micro rolling process, introduce the manufacturing…
Abstract
Purpose
The purpose of this paper is to report a new direct metal manufacturing method which integrates freeform deposition process and micro rolling process, introduce the manufacturing principle and show the advantages of this method.
Design/methodology/approach
This paper introduces the hybrid manufacturing principle and devices first. Then, the key parameters of hybrid manufacturing process are studied by contrast experiments. The results of comparisons of manufacturing accuracy, microstructure and tensile test between freeform fabricated parts and hybrid manufactured parts show the advantages of this new direct manufacturing method.
Findings
The experiments results show that the accuracy of hybrid manufacturing method is improved obviously comparing with arc-based freeform deposition manufacturing method; the microstructure of the hybrid manufacturing part turns into cellular crystal instead of dendrite; the tensile strength of the part increases by 33 percent and the tensile deformation improved more than two times.
Originality/value
The paper presents a new hybrid direct metal manufacturing method for the first time. The hybrid manufacturing devices are developed. The experiments results show that the hybrid manufacturing method can be used on directly fabricating large metal components with outstanding quality, efficiency and low cost. The application prospect is great.
Details
Keywords
Xinhong Xiong, Zhang Haiou and Wang Guilan
The purpose of this paper is to develop a novel hybrid plasma deposition and milling (HPDM). For solving the bottleneck problem of low‐surface quality in existing direct rapid…
Abstract
Purpose
The purpose of this paper is to develop a novel hybrid plasma deposition and milling (HPDM). For solving the bottleneck problem of low‐surface quality in existing direct rapid metal prototyping technologies.
Design/methodology/approach
HPDM uses plasma deposition as an additive and conventional milling as subtractive technique, which synthesizes the advantages of both processes. Compared to other laser or electron beam deposition processes, plasma deposition used in HPDM is one of the most economic ways of depositing metals, CNC assisted to ensure the precision of the manufactured parts simultaneity.
Findings
This paper focus on the experimental investigation to find the basic process characteristics, the optimization of the process parameters such as transferred arc current, workpiece's speed, powder flow rate and feed per tooth using a statistical approach. Some metal parts, for instance, metal torsional vane, are then trial‐manufactured.
Research limitations/implications
The manufacturing cycle of HPDM is longer than simplex direct metal rapid prototyping, and the surface accuracy should be further investigated.
Practical implications
HPDM is a very useful and effective method to manufacture metal parts with fine surface state directly.
Originality/value
This paper describes a novel process and manufacturing system for fabrication metal prototyping direct, which can improve the inside and outside quality of the metal rapid prototypes.
Details
Keywords
Nastaran Taherparvar, Reza Esmaeilpour and Mohammad Dostar
This paper aims to examine the effect of customer knowledge management (CKM) on continuous innovation and firm performance in 35 private banks in Guilan (Iran). CKM emerges as an…
Abstract
Purpose
This paper aims to examine the effect of customer knowledge management (CKM) on continuous innovation and firm performance in 35 private banks in Guilan (Iran). CKM emerges as an important and effective system for innovation capability and firm performance. However, the role of CKM in innovation and performance is not well understood.
Design/methodology/approach
Data have been collected via questionnaires from managers of private banks in Guilan. Feedback was received from 265 managers in 350 distributed questionnaires, and hypotheses were tested using the structural equation modelling.
Findings
The results of this paper indicate that knowledge from customers has a positive impact on both innovation speed and innovation quality as well as operational and financial performances. Also, our results demonstrate a different effect of knowledge about customer and knowledge for customers on various dimensions of innovation and firm performance. By using customer’s knowledge flows, firms will be aware of external environment and new changes in customers’ needs and so will be more innovative and perform better.
Practical implications
CKM is known as an important system to connecting internal environment to external environment to create novel ideas. The results of this paper shed light on the consequences of CKM on firms and provide support for the importance of CKM to enhance innovation capacity and firm performance.
Originality/value
This article is one of the first to find empirical support for the role of CKM within firms and its importance on innovation capability and firm performance. This study can provide valuable insights and guidance for researchers and managers as well.