Download or read book Study of Hot Tearing in Cast and Wrought Aluminum Alloys written by Qinxin Wu and published by . This book was released on 2012 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: During the solidification process in casting, hot tearing may occur. It is a severe defect that normally involves the formation of a macroscopic tear, which generates cracks either on the surface or inside the casting. Over the past decades, many strategies have been developed to evaluate the hot tearing tendency. Unfortunately, most of the tests can only provide qualitative information. Therefore, a reliable and quantitative test to evaluate hot tearing in aluminum alloys is highly desirable. To address this issue, WPI and CANMET MTL (both members of the Light Metal Alliance) jointly developed a quantitative hot tearing test and established a specific methodology. Using a constrained rod mold, the hot tearing formation can be quantitatively studied by measuring the contraction force, time and temperature during solidification for a restrained casting or linear contraction, time and temperature for a relaxed casting. This study investigated cast aluminum alloys A380.1 and A390 and wrought aluminum alloys 6061 and 7075. The results show that wrought aluminum alloys have a much stronger hot tearing tendency than cast aluminum alloys based on a quantitative analysis. Also, the study involves the effects of adding strontium and oxides respectively into the cast aluminum alloy A380.1. Compared with the pure A380.1 alloy, the introduction of strontium decreases the hot tearing tendency, while the inclusion of oxide greatly increases the hot tearing. The information obtained through these tests provides a database of hot tearing phenomenon and establishes a new hot tearing index.
Download or read book A Study of Hot Tearing in Wrought Aluminium Alloys written by Shan Lin and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Hot Tearing in Wrought Aluminum Alloys written by and published by . This book was released on 1999 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Hot Tearing in Wrought Aluminum Alloys written by Shan Lin and published by . This book was released on 1999 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Study of Hot tearing During Solidification of Aluminum Alloys Via the Acoustic Emission Method written by Xiaojin Li and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hot Tearing in Cast Aluminum Alloys Measures and Effects of Process Variables written by Shimin Li and published by . This book was released on 2010 with total page 248 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: Hot tearing is a common and severe defect encountered in alloy castings and perhaps the pivotal issue defining an alloy's castability. Once it occurs, the casting has to be repaired or scraped, resulting in significant loss. Over the years many theories and models have been proposed and accordingly many tests have been developed. Unfortunately many of the tests that have been proposed are qualitative in nature; meanwhile, many of the prediction models are not satisfactory as they lack quantitative information, data and knowledge base. The need exists for a reliable and robust quantitative test to evaluate/characterize hot tearing in cast alloys. This work focused on developing an advanced test method and using it to study hot tearing in cast aluminum alloys. The objectives were to: 1) develop a reliable experimental methodology/setup to quantitatively measure and characterize hot tearing; and 2) quantify the mechanistic contributions of the process variables and investigate their effects on hot tearing tendency. The team at MPI in USA and CANMET-MTL in Canada has collaborated and developed such a testing setup. It consists mainly of a constrained rod mold and the load/displacement and temperature measuring system, which gives quantitative, simultaneous measurements of the real-time contraction force/displacement and temperature during solidification of casting. The data provide information about hot tearing formation and solidification characteristics, from which their quantitative relations are derived. Quantitative information such as tensile coherency, incipient crack refilling, crack initiation and propagation can be obtained. The method proves to be repeatable and reliable and has been used for studying the effects of various parameters (mold temperature, pouring temperature and grain refinement) on hot tearing of different cast aluminum alloys. In scientific sense this method can be used to study and reveal the nature of the hot tearing, for industry practice it provides a tool for production control. Moreover, the quantitative data and fundamental knowledge gained in this thesis can be used for validating and improving the existing hot tearing models.
Download or read book Solidification of Aluminum Alloys written by Men G. Chu and published by Wiley-TMS. This book was released on 2004-03 with total page 430 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume addresses progress in the application of solidificationprinciples to the production of aluminum alloys. Topics includemicrostructure evolution, phase formation and solidification pathanalysis, grain refinement, micro/macro-segregation, mechanicalbehavior/properties in the mushy state, solidificationcracking/tearing, gas/shrinkage porosity formation, effect ofimpurities/trace elements, and the impact of cast structure on thesubsequent fabrication and properties of finished products. Paperson the experimental or theoretical simulation of solidificationaspects of casting processes including direct chill casting,continuous casting, shaped casting, semi-solid processing, andother advanced casting technologies are also included, as well asexamples showing the use of solidification principles to solveindustrial problems. From ahref="http://www.tms.org/Meetings/Annual-04/AnnMtg04Home.html"target="_blank"2004 TMS Annual Meeting/a to be held inCharlotte, North Carolina, March 14 - 18, 2004.
Download or read book Resource Recovery and Recycling from Metallurgical Wastes written by S.R. Ramachandra Rao and published by Elsevier. This book was released on 2011-08-29 with total page 581 pages. Available in PDF, EPUB and Kindle. Book excerpt: Resource recovery and recycling from millions of tons of wastes produced from industrial activities is a continuing challenge for environmental engineers and researchers. Demand for conservation of resources, reduction in the quantity of waste and sustainable development with environmental control has been growing in every part of the world. Resource Recovery and Recycling from Metallurgical Wastes brings together the currently used techniques of waste processing and recycling, their applications with practical examples and economic potentials of the processes. Emphasis is on resource recovery by appropriate treatment and techniques. Material on the subject is scatterend in waste management and environmental related journals, conference volumes and government departmental technical reports. This work serves as a source book of information and as an educational technical reference for practicing scientists and engineers, as well as for students. - Describes the currently used and potential techniques for the recovery of valuable resources from mineral and metallurgical wastes - Discusses the applications to specific kinds of wastes with examples from current practices, as well as eht economics of the processes - Presents recent and emerging technologies of potentials in metal recycling and by-product utilization
Download or read book Hot Tearing and Constitutive Behaviour of Semi solid Aluminum Alloys written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The occurrence of hot tearing during solidification is one of the major factors influencing both the quality and productivity of aluminum castings. In order to reduce the formation of hot tears, quantitative information regarding both hot tearing formation and semi-solid deformation is essential. In this study, the mechanisms of hot tearing and semi-solid deformation have been investigated via two novel techniques: x-ray micro-tomography on material deformed in the semi-solid region, and development of a three phase microstructural model based on a geometry derived from a Voronoi diagram with rounded corners and porosity. Numerical techniques were utilized to quantify both the size evolution and orientation of internal damage relative to void growth. In order to conduct the above research, a new semi-solid tensile deformation methodology was devised which uses a two thermocouple control technique to enable accurate measurement of semi-solid tensile strength and ductility. The experimental work was conducted on the aluminum - magnesium alloy AA5182 in the as-cast and hot isostatic pressing (HIP) states. The x-ray micro-tomography technique was used to observe that semi-solid deformation is accommodated by internal damage via growth of as-cast porosity and the nucleation of new damage-based voids. As the volume fraction of damage increases, the growth of voids occurs in an orientation perpendicular to the loading direction, both through expansion within the grain boundary liquid and via coalescence between voids. The damage then localizes, causing failure. The finite element semi-solid microstructural model was used to explore the effects of fraction solid, fraction porosity, and grain size on semi-solid constitutive behaviour. The simulations revealed that increased grain size and fraction porosity lead to a reduction in flow stress for a given fraction solid. Furthermore, local strain accumulation was linked to hot tearing, since strain localizes in the liquid very.
Download or read book Extrusion of Aluminium Alloys written by T. Sheppard and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: In recent years the importance of extruded alloys has increased due to the decline in copper extrusion, increased use in structural applications, environmental impact and reduced energy consumption. There have also been huge technical advances. This text provides comprehensive coverage of the metallurgical, mathematical and practical features of the process.
Download or read book Fundamental Study of Hot Tearing Mechanisms of Aluminium silicon Alloys written by Joseph Langlais and published by . This book was released on 2006 with total page 438 pages. Available in PDF, EPUB and Kindle. Book excerpt: "A theoretical model was updated from previous work using more realistic metallurgical quantities. This research led also to the development of a probalistic model (cellular automata) to simulate the microstructure of the cast sample. The model has been used to determine a crack propagation coefficient (CPC) that was used in the theoretical model to better represent the hot tear propagation." --
Download or read book The modeling of hot tearing in aluminium alloy written by Weili Wu and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Effect of Rate of Solidification on Hot Tearing in Aluminum Alloys written by Jacob D. Gubbay and published by . This book was released on 1956 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Studies on the Hot Cracking Behaviour of Aluminium Alloys written by David Warrington and published by . This book was released on 1990 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Hot Tearing and Deformation in Direct chill Casting of Aluminium Alloys written by Suyitno and published by . This book was released on 2005 with total page 181 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Shape Casting written by Murat Tiryakioǧlu and published by John Wiley & Sons. This book was released on 2011-04-12 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a career spanning almost six decades, Prof. John T. Berry has made significant contributions towards building our understanding of solidification and process-structure-property relationships in shaped castings. Celebrating his contributions, the Fourth International Shape Casting Symposium, which takes place at the 2011 TMS Annual Meeting & Exhibition, has been organized in his honor. Shape Casting 2011 contains the proceedings of the symposium in which scientists and engineers from around the world presented their own research findings, discussed challenges in the field, and projected future directions. Papers explore such topics as liquid metal quality; filling and feeding systems; process modeling for shaped castings; structure-property relationships; performance of shaped castings; and machinability of castings.
Download or read book Strain Evolution During Hot Tearing in Aluminium Alloys written by and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Hot tearing refers to cracks that frequently occur within the mushy zone during cooling from the liquid to solid state during shape and ingot casting. Both ferrous and non-ferrous alloys may be affected, and there is some evidence to suggest those with long freezing ranges are more susceptible. Due to the nature of this defect the economic impact is often significant and can result in an immediate productivity loss. It is therefore important for industry to be able to better predict the susceptibility of various alloys to hot tearing. Various theories have been proposed and several different types of experimental methods have been developed to interpret the properties of alloys in the semi-solid state. However, many of these techniques do not produce good quantitative data (i.e. strain) that can be used to calibrate a thermal-mechanical computer simulation of casting. Existing experimental methods often measure strain indirectly by means of a load train frozen into the end of the casting. However, local strain at the hot tear initiation site would be more valuable for computer model calibration. Clearly, the use of traditional measurement techniques, such as strain gauges, is not a viable option and therefore an alternative was investigated. In this work the use of digital image correlation to determine the evolution of strain and strain at the onset of localisation resulting in a hot tear has been evaluated. Data has been determined for aluminium alloys AA6111, AA3104, CA32118, Al-0.5% wt pct Cu under slow cooling conditions and AA3003 under directional solidification using a water cooled copper chill. A new hot tearing experiment has been developed which localises strain to promote hot tearing to occur in only one region of the casting and is cooled by directional solidification. Images of this region were captured during solidification via a glass window embedded in the mould of the experiment. These images were correlated with each other to determine strain accu.
