Study on Multi-Alloy Ingots Produced Using Hot-Top DC Casting Approach

2015 ◽  
Vol 1095 ◽  
pp. 199-204
Author(s):  
Xing Han ◽  
Jian Zhong Cui
Keyword(s):  
Casting Process ◽  
Element Distribution ◽  
Interface Zone ◽  
New Approach ◽  
Hot Top ◽  
Layer Composite ◽  
Supporting Layer ◽  
Dc Casting ◽  
The Impact ◽  
Interface Bonding Strength

In this paper, a new approach that using hot-top DC casting process to produce multi-alloy ingots is present. The different type and size of composite and cladding ingots (4045/3004/4045 three-layer composite ingots with section 630mm by 1500mm and 4045/3003 cladding ingot with Φ140mm/Φ110mm in diameter) are fabricated by this approach. The macro-morphologies and microstructures of the ingots, the temperature distribution and the element distribution in the interface zone were investigated, and the interface bonding strength was measured. The results show that the solid supporting layer formed on the cooling plates plays a key role in the casting process of composite ingots. The solid supporting layer can prevent the blending of two melts by resisting the impact of alloy melt, which ensures the stable casting process and casting high quality composite ingots, because the contact height is increased using hot-top DC casting. In addition, fabrication and properties of 4045/3004/4045 three-layer composite ingots with section 630mm by 1500mm are reported in detail.

The Numerical and Experimental Study on DC Casting Process of Three-Layer Composite Ingots of 4045/3004/4045 Aluminum Alloys

2014 ◽  
Vol 783-786 ◽  
pp. 325-330
Author(s):  
Ke Qin ◽  
Hai Tao Zhang ◽  
Jian Zhong Cui ◽  
Hui Xue Jiang
Keyword(s):  
Casting Process ◽  
Element Distribution ◽  
Interface Bonding ◽  
Interface Zone ◽  
Layer Composite ◽  
Cooling Intensity ◽  
Supporting Layer ◽  
Dc Casting ◽  
The Impact ◽  
Interface Bonding Strength

In this study, experiments are combined with numerical simulation to study the temperature field and flow field during the casting process of 4045/3004/4045 three-layer composite ingots with section of 500mm×420mm. The effects of casting temperature, casting speed, contacting height and cooling intensity of cooling plate on the casting process were discussed. The macro-morphologies and microstructures of the composite ingots, the temperature distribution and the element distribution in the interface zone were investigated, also the interface bonding strength was measured. The optimal parameters for casting composite ingots were obtained. Results show that the solid supporting layer formed on the cooling plates plays a key role in the casting process of composite ingots. The solid supporting layer can prevent the blending of two melts by resisting the impact of alloy melt, which ensures the stable casting process and casting high quality composite ingots.

Simulation of Low Frequency Electromagnetic DC Casting

2014 ◽  
Vol 790-791 ◽  
pp. 390-395 ◽  
Author(s):  
Nejc Kosnik ◽  
Robert Vertnik ◽  
Božidar Šarler
Keyword(s):  
Solid Phase ◽  
Low Frequency ◽  
Casting Process ◽  
Direct Chill ◽  
Temperature Fields ◽  
Step Method ◽  
Fractional Step Method ◽  
Hot Top ◽  
Induction Equation ◽  
Dc Casting

A comprehensive multiphysics model has been developed to describe the effect of the low frequency electromagnetic field (LFEM) [1, on solidification in the hot-top Direct-Chill (DC) casting [ of round aluminium alloy billets. The volume averaged equations and the rigid solid phase assumption are assumed for fluid flow and heat transfer [. The electromagnetic induction equation for the field imposed by the coil is solved using the diffuse approximate method (DAM), structured in axial symmetry with Gaussian weight function, 6 polynomial basis and 9 nodded domains. The heat, mass, and momentum transfer equations are solved in primitive variables by meshless [ method using 5 nodded domains of influence and 5 scaled multiquadrics radial basis functions, using collocation. Explicit time stepping is used. Pressure-velocity coupling is performed by the fractional step method. The effects of intensity and frequency of the LFEM [ on the velocity and temperature fields is investigated. A comparison of the calculated results with different LFEM field process variables with that of the conventional hot-top DC casting process indicates that the velocity patterns, the temperature profiles, and the shape of the sump could be modified remarkably.

A Novel Ultrasonic Casting Process Using Controlled Cavitation and Melt Flow in Hot Top Molds

2014 ◽  
Vol 794-796 ◽  
pp. 124-129 ◽  
Author(s):  
Sergey Komarov ◽  
Yasuo Ishiwata ◽  
Yoshihiro Takeda
Keyword(s):  
Casting Process ◽  
High Amplitude ◽  
Simplified Model ◽  
Ultrasonic Vibrations ◽  
Melt Flow ◽  
Hot Top ◽  
Primary Si ◽  
Highly Effective ◽  
Dc Casting ◽  
Controlled Flow

The present work introduces a novel ultrasonic DC casting process which allows producing billets of hypereutectic Al-Si alloys with greatly refined and uniformly distributed particles of primary Si. In the process, ultrasonic vibrations are introduced into an Al-17Si-0.01~0.03P melt in a hot top positioned on the mold by using a high-amplitude ceramic sonotrode. The hot top design and sonotrode arrangement provided a highly effective cavitation treatment of the melt in the hot top and well-controlled flow in the sump. A simplified model is proposed to explain the obtained results.

Survey Data Quality in Analyzing Harmonized Indicators of Protest Behavior: A Survey Data Recycling Approach

2021 ◽  
pp. 000276422110216
Author(s):  
Kazimierz M. Slomczynski ◽  
Irina Tomescu-Dubrow ◽  
Ilona Wysmulek
Keyword(s):  
Data Processing ◽  
Data Quality ◽  
Survey Data ◽  
A Priori ◽  
Data Sets ◽  
New Approach ◽  
Survey Quality ◽  
Survey Error ◽  
Ex Post ◽  
The Impact

This article proposes a new approach to analyze protest participation measured in surveys of uneven quality. Because single international survey projects cover only a fraction of the world’s nations in specific periods, researchers increasingly turn to ex-post harmonization of different survey data sets not a priori designed as comparable. However, very few scholars systematically examine the impact of the survey data quality on substantive results. We argue that the variation in source data, especially deviations from standards of survey documentation, data processing, and computer files—proposed by methodologists of Total Survey Error, Survey Quality Monitoring, and Fitness for Intended Use—is important for analyzing protest behavior. In particular, we apply the Survey Data Recycling framework to investigate the extent to which indicators of attending demonstrations and signing petitions in 1,184 national survey projects are associated with measures of data quality, controlling for variability in the questionnaire items. We demonstrate that the null hypothesis of no impact of measures of survey quality on indicators of protest participation must be rejected. Measures of survey documentation, data processing, and computer records, taken together, explain over 5% of the intersurvey variance in the proportions of the populations attending demonstrations or signing petitions.

Telephone-based consultation in an acute eye clinic service: A patient satisfaction survey

2021 ◽  
pp. 112067212110307
Author(s):  
Julia Sieberer ◽  
Patrick Hughes ◽  
Indy Sian
Keyword(s):  
Healthcare Professionals ◽  
Medical Specialties ◽  
New Approach ◽  
High Satisfaction ◽  
Negative Comments ◽  
Patient Responses ◽  
Set Up ◽  
Strongly Agree ◽  
The Impact ◽  
Park Hospital

Objectives: The coronavirus pandemic has forced healthcare staff across all medical specialties to adapt new and different ways of working. A new approach has been set up in the Acute Referral Clinic (ARC) at Musgrove Park Hospital and a survey has been conducted to measure the impact of the new method on patient and healthcare professionals’ satisfaction with the new service. Methods: A telephone-based consultation was introduced in ARC at Musgrove Park Hospital in March 2020 and patients were instructed to fill out a questionnaire containing eight items using a Likert Scale 1 (‘very poor/disagree’) to 4 (‘very good/strongly agree’) plus two boxes for open positive and negative comments respectively. Likewise a questionnaire was designed in order to assess the healthcare professionals’ satisfaction using the new approach. Data collection took place over a two month period between the end of March 2020 and end of May 2020. The data underwent quality control and was analysed using descriptive statistics. Results: Patient responses illustrated high satisfaction scores with an overall rating of very good (89.4%). The healthcare professionals’ rating of the service was good (28.6% – ‘very good/strongly agree’, 57.1% – ‘good/agree’). The safety rating of the new approach was overall rated ‘very good’ with 90.4% and 71.4% of patients and healthcare professionals respectively. Conclusions: The telephone consultations introduced in the wake of COVID-19 are well accepted by both patients and doctors. There are some limitations of the approach, foremost being consultation time and clinic space but these do not outweigh the general benefit of this format amidst a pandemic setting.

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