Predicting the combined effect of TiO2 nano-particles and welding input parameters on the hardness of melted zone in submerged arc welding by fuzzy logic

Masood Aghakhani,Mohammad Reza Ghaderi,Maziar Mahdipour Jalilian,Ali Ashraf Derakhshan 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.7

Submerged arc welding (SAW) is a high-quality arc welding process used in heavy industries for welding thick plates. In this process,selecting appropriate values for the input parameters is required for high productivity and cost effectiveness. A very important weld quality characteristic affected by welding input parameters is the hardness of melted zone (HMZ). This paper reports the applicability of fuzzy logic (FL) to predict HMZ in the SAW process which is affected by the combined effect of TiO2 nano-particles and welding input parameters. The arc voltage, welding current, welding speed, contact tip-to-plate distance, and TiO2 nano-particles were used as input parameters and HMZ as the response to develop FL model. A five-level five-factor central composite rotatable design (CCRD) was used in the experiments to generate experimental data. Experiments were performed, and HMZs were measured. The predicted results from FL were compared with the experimental data. The correlation factor value obtained was 99.99% between the measured and predicted values of HMZ. The results showed that FL is an accurate and reliable technique for predicting HMZ because of its low error rate.

Optimization of FSW of Nano-silica-reinforced ABS T-Joint using a Box-Behnken Design (BBD)

Mahyar Motamedi Kouchaksarai,Yasser Rostamiyan Techno-Press 2023 Advances in nano research Vol.14 No.2

This experimental study investigated friction stir welding (FSW) of the acrylonitrile-butadiene-styrene (ABS) T-joint in the presence of various nano-silica levels. This study aim to handle the drawbacks of the friction stir welding (FSW) of an ABS T-joint with various quantity of nanoparticles and assess the performance of nanoparticles in the welded joint. Moreover, the relationship between the nanoparticle quantity and FSW was analyzed using response surface methodology (RSM) Box-Behnken design. The input parameters were the tool rotation speed (400, 600, 800 rpm), the transverse speed (20, 30, 40 mm/min), and the nano-silica level (0.8, 1.6, 2.4 g). The tensile strength of the prepared specimens was determined by the universal testing machine. Silica nanoparticles were used to improve the mechanical properties (the tensile strength) of ABS and investigate the effect of various FSW parameters on the ABS T-joint. The results of Box-Behnken RSM revealed that sound joints with desired characteristics and efficiency are fabricated at tool rotation speed 755 rpm, transverse speed 20 mm/min, and nano-silica level 2.4 g. The scanning electron microscope (SEM) images revealed the crucial role of silica nanoparticles in reinforcing the ABS T-joint. The SEM images also indicated a decrease in the nanoparticle size by the tool rotation, leading to the filling and improvement of seams formed during FSW of the ABS T-joint.

고강도 강판 저항 점용접부 강도 및 파단에 미치는 Paint Baking의 영향

최철영 ( Chul Young Choi ),이동윤 ( Dong Yun Lee ),김인배 ( In Bae Kim ),김양도 ( Yang Do Kim ),박영도 ( Yeong Do Park ) 대한금속재료학회(구 대한금속학회) 2011 대한금속·재료학회지 Vol.49 No.12

Conventional fracture tests of resistance spot welds have been performed without consideration of the paint baking process in the automobile manufacturing line. The aim of this paper is to investigate the effect of the paint baking process on load carrying capacity and fracture mode for resistance spot welded 590 dual phase (DP), 780DP, 980DP, 590 transformation in duced plasticity (TRIP), 780TRIP and 1180 complex phase (CP) steels. With paint baking after resistance spot welding, the l-shape tensile test (LTT) and nano-indentation test were conducted on the as-welded and paint baked samples. Paint baking increased the load-carrying capacity of the resistance spot welded samples and improved the fracture appearance from partial interfacial fracture (PIF) to button fracture (BF). Improvement in fracture appearance after LTT is observed on weldments of 780 MPa grade TRIP steels, especially in the low welding current range with paint baking conditions. The higher carbon contents (or carbon equivalent) are attributed to the low weldability of the resistance spot welding of high strength steels. Improvement of the fracture mode and load carrying ability has been achieved with ferrite hardening and carbide formation during the paint baking process. The average nano-indentation hardness profile for each weld zone shows hardening of the base metal and softening of the heat affected zone (HAZ) and the weld metal, which proves that microstructural changes occur during low temperature heat treatment.

Investigation of Fe-rich fragments in aluminum-steel friction stir welds <i>via</i> simultaneous Transmission Kikuchi Diffraction and EDS

Abbasi, Majid,Dehghani, Morteza,Guim, Hwan-Uk,Kim, Dong-Ik Elsevier 2016 Acta materialia Vol.117 No.-

<P>An attempt has been made to investigate Fe-rich fragments and surrounding intermetallic compounds in aluminum-steel friction stir welds using conventional EBSD + EDS as well as advanced Transmission Kikuchi Diffraction (TKD). Results indicate that the fragments are covered by a layer of orthorhombic Al5Fe2. This layer is surrounded by a mixed region composed of sub-micrometer Al3Fe crystals in a matrix of Al nano grains. Employing high beam current TKD on electron-transparent samples enables investigation of sub-micrometer grains in the mixed region with a higher spatial resolution than conventional EBSD. As a result, nano-twinning in Al in the mixed region has been observed. Microstructural and texture results imply that Fe-rich fragments travel through the Al matrix under extreme shear forces, severely refining Al grains, and inducing nano-twinning. Due to extreme shear forces and Fe outward diffusion, fine steel fragments dissolve in the surroundings leading to the nucleation of nano Al3Fe crystals particularly along Al grain boundaries. Al3Fe crystals consume the Al matrix as they grow in size and fraction. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.</P>

Combination of nano-particle deposition system and friction stir spot welding for fabrication of carbon/aluminum metal matrix composite joints of dissimilar aluminum alloys

Hong, Sung-Tae,Das, Hrishikesh,Oh, Hyun-Seok,Nasim, Mohammad Nur E Alam Al,Chun, Doo-Man Elsevier 2017 CIRP annals ... manufacturing technology Vol.66 No.1

<P><B>Abstract</B></P> <P>A nano-particle deposition system is combined with friction stir spot welding (FSSW) of dissimilar aluminum alloys to fabricate a carbon/aluminum metal matrix composite (MMC) joint. Carbon materials in the form of graphite powder are deposited on an aluminum sheet at room temperature. Lap joints of dissimilar aluminum alloys are fabricated via FSSW using the carbon-deposited aluminum sheet as the upper sheet of the joint. The Raman spectroscopy confirms that carbon/aluminum MMC is successfully fabricated in the joint. The strength and toughness of the joint are clearly enhanced by fabricating the MMC, as shown in the result of mechanical tests.</P>

금속블록 채널이 있는 유도형 전력선통신에 관한 연구

손경락(Kyung-Rak Sohn),김현식(Hyun-Sik Kim) 한국전기전자학회 2021 전기전자학회논문지 Vol.25 No.1

조선소에서 선체 블록과 용접 피더의 위치를 알면 작업자의 위치 정보를 쉽게 얻을 수 있다. 이 데이터는 작업장 안전 모니터링 시스템 구축에 매우 유용하다. 그러나 선체 구조와 용접 공정의 특수성 때문에 작업장에 고정 통신망을 적용하기 어렵다. 본 연구에서는 전용 통신선을 대신할 수 있는 유도 전력선 통신을 선체블록과 같은 금속매체에 적용하는 기술을 검토하였다. 용접기의 전원 케이블에 설치할 유도 결합기로 페라이트 코어를 사용하였고, 금속 블록의 지지대에 체결할 결합기로 나노 결정질 코어를 적용하였다. 제안된 커플러는 COMSOL AC/DC 모듈로 3차원 모델링 하였고 동작 원리를 시각화하기 위하여 유한 요소 해석을 수행하였다. 알루미늄 프로파일을 사용한 금속블록 통신 성능 테스트에서 용접 전극의 블록 접촉으로 통신 채널이 형성되었을 때 대역폭은 6 Mbps 이상 유지되었다. If we know the location of the hull block and the welding feeder in the shipyard, we can easily obtain the location information of the worker. That data is very useful for implementing a workplace safety monitoring system. However, it is difficult to apply a fixed communication network to the workplace due to the specificity of the hull structure and welding process. In this study, inductive power line communication, which can replace dedicated communication line, was reviewed. A ferrite core was used as an inductive coupler to be installed on the power cable of the welding machine, and a nano-crystalline core was applied as a coupler to be fastened to the support rod of the metal block. In order to visualize the operating principle of the proposed couplers, 3D modeling and finite element analysis were performed with the COMSOL AC/DC module. In the communication performance test using an aluminum profile, when the communication channel was formed by the contact of the welding electrode, the bandwidth was kept above 6 Mbps.

Friction welding of multi-shape ABS based components with Nano Zno and Nano Sio₂ as welding reinforcement

Afzali, Mohammad,Rostamiyan, Yasser Techno-Press 2022 Coupled systems mechanics Vol.11 No.3

Due to the high usage of ABS in industries, such as aerospace, auto, recreational devices, boat, submarines, etc., the purpose of this project was to find a way to weld this material, which gives advantages, such as affordable, high speed, and good connection quality. In this experimental project, the friction welding method was applied with parameters such as numerical control (NC) machine with two different speeds and three cross-sections, including a flat surface, cone, and step. After the end of the welding process, samples were then applied for both tensile and bending tests of materials, and the results showed that, with increasing the machining velocity Considering of samples, the friction of the surface increased and then caused to increase in the surface temperature. Considering mentioned contents, the melting temperature of composite materials increased. This can give a chance to have a better combination of Nanomaterial to base melted materials. Thus, the result showed that, with increasing the weight percentage (wt %) of Nanomaterials contents, and machining velocity, the mechanical behavior of welded area for all three types of samples were just increased. This enhancement is due to the better melting process on the welded area of different Nano contents; also, the results showed that the shape of the welding area could play a significant role, and by changing the shape, the results also changed drastically.A better shape for the welding process was dedicated to the step surface.

Nanoscale Patterning and Welding by Solvent-free Dry Particle Spray and Focused Ion Beam

Jung-Oh Choi,Chung-Soo Kim 한국정밀공학회 2014 International Journal of Precision Engineering and Vol.1 No.3

Nano particle deposition system (NPDS) is one of dry particle spray methods such as cold spray and aerosol deposition. It can be used to build structures from metals, ceramics, and nanomaterials without any solvents at room temperature and under low vacuum conditions, reducing energy consumption. Recent advances in dry particle spray techniques, including NPDS, have demonstrated their use with advanced nanomaterials such as carbon nanotube. However, to date, this process has not been successfully scaled down to 100-nm scales. Here, we demonstrate the use of NPDS as dry particle spray method in the nanoscale regime with the help of a focused ion beam for nanoscale manufacturing. Nanoscale patterning and welding were achieved using a nano particle deposition system with miniaturized feature sizes that were smaller than 100 nm in scale.

Super304H 용접 이음의 미세조직 및 인장물성에 미치는 고온 열화의 영향

송근동(Geun Dong Song),황정호(Jeong Ho Hwang),김대웅(Dae-Woong Kim),정인현(In Hyun Cheong),홍성구(Seong-Gu Hong),한준희(Junhee Hahn) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.4

Super304H 은 초임계 이상 조건에서 작동하는 화력 발전소의 보일러 튜브 재료로 유망한 후보이며, 이들의 용접 이음에 대한 기계적 특성은 화력 발전소의 구조적 신뢰성에서 중요한 역할을 한다. 본 연구에서는 Super304H 용접 이음의 미세조직 및 인장 물성에 대한 고온 열화의 영향을 조사하였다. 고온 열화 시간의 증가함에 따라 Super304H 용접 이음의 모재와 용접금속에서는 서로 다른 미세조직의 변화가 발생하였으며, 이로 인해 용접 이음의 재료 불균일성을 심화되어 용접 금속에서 변형이 집중된다는 것을 관찰하였다. Super304H 용접 이음의 모재에서는 고온 열화에 의해 크롬 탄화물이 입계를 따라 생성되었으며, 입내에서는 미세한 Nb (C, N)이 새롭게 석출되었다. 용접 금속의 경우 수지상 내부에서는 미세조직의 큰 변화가 나타나지 않았지만, 수지상 간에서는 고온 열화 시간이 증가함에 따라 미세한 크롬탄화물이 석출되었다. 이러한 미세조직 변화로 인해 모재와 용접금속의 수지 상간에서는 국부적인 경도가 증가한 반면, 용접금속의 수지상 내부는 큰 변화가 없었다. 결과적으로 고온 열화에 의해 심화된 국부적 경도 불균일성은 Super304H 용접 이음의 Soft zone을 모재에서 용접금속의 수지상 중심부로 전환시켜 변형의 국재화를 야기하였으며, 이로 인해 인장 파단 위치가 모재에서 용접금속으로 이동되었다. Super304H steel is a promising candidate for boiler tube materials in thermal power plants operating under ultra-supercritical conditions, and the mechanical properties of its welded joint play a key role in the structural reliability of the thermal power plants. In this work, the effect of thermal ageing on the microstructure and tensile properties of Super304H welded joint was investigated. We found that a thermal ageing promotes different microstructural evolutions in the base metal and weld metal, deepening material inhomogeneity in the welded joint, and thereby triggering strain localization in the weld metal. With increasing thermal ageing time, Cr23C6 carbides precipitated in the interdendritic region of the weld metal and at the austenitic grain boundary of the base metal, and Nb (C, N) phases precipitated in the interior of austenitic grain in the base metal. These microstructure evolutions resulted in that local hardness of base metal local increased, whereas there was no significant change in the dendrite core, retaining its initial hardness. The intensified local hardness inhomogeneity caused the softest zone at the welded joint, wherein strain localization occurred, serving as a crack nucleation site and propagation path, to shift from the base metal to the weld metal (dendrite core). Consequently, thermal ageing effect induced a shift in the failure location from the base metal to the weld metal.

Hybrid Transparent Electrodes of Silver Nanowires and Carbon Nanotubes by Plasmonic Welding

Jongsoo Lee(이종수),Ju Yeon Woo,Ju Tae Kim,Byung Yang Lee,Chang-Soo Han 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11

We report highly transparent and flexible AgNW/SWCNT hybrid networks on PET substrates combined with plasmonic welding for securing ultrahigh stability in mechanical and electrical properties under severe welding at the junction of AgNWs and leads strong adhesion between AgNW and SWCNT as well as between hybrid structure and substrate. The initial sheet resistance of plasmon treated AgNW/SWCNT hybrid film was 26Ω sq-1, with >90% optical transmittance over the wavelength range 400-2700 nm. Following 200 cycles of convex/ concave bending with a bending radius of 5 mm, the sheet resistance changed from 26 to 29 Ω sq-1. This hybrid structure combined with the plasmonic welding process provided excellent stability, low resistance, and high transparency, and is suitable for highly flexible electronics applications, including touch panels, solar cells, and OLEDs.