Softening during the hot deformation of steel

The behaviour of steel undergoing hot deformation was examined with the aim of better understanding the softening mechanisms operating during industrial hot strip rolling. These softening mechanisms can significantly influence the deformation force required to attain a given reduction in thickness, and this work answered a number of questions with regard to the transition between softening mechanisms.

Low temperature formability of differently processed AZ31B magnesium alloy sheets

The research found changes in the performance (formability) of magnesium alloy sheets with a history of different processes. A key outcome found that the steel sheet metal processing of rolling and heat treatment caused a detrimental effect. The material's internal deformation was found to be linked to the poor formability.

Mechanical properties and blow forming of rolled AZ31 Mg alloy sheet

Rolling was conducted at 373-673 K for AZ31 Mg alloy; mechanical properties of the rolled Mg alloy were investigated by tensile and blow forming tests. The grain sizes of all the rolled specimens were smaller than that of the specimen prior to rolling. At tensile temperatures under 373 K, the rolled specimens showed much higher 0.2% proof stresses than the non-rolled specimens due to their fine-grained microstructure. However, the strength of the rolled specimens decreased significantly at 473 K. Superplastic behavior was obtained at 573-723 K for the specimens rolled at 498 K. Blow forming tests demonstrated that specimens rolled at 498 K exhibited a high degree of formability at 723 K.

Cultural connections across time and place : Wardell's late 19th century Genazzano FCJ College Kew

The Catholic Church was profoundly affected by the 1872 Victorian Education Act, which made education secular, compulsory and free, and led to the withdrawal of state aid to religious schools. In order for the Church to run its own schools, it had to look overseas for help and invited religious teaching orders, such as the Faithful Companions of Jesus (FCJs) to set up schools in Victoria, Australia. In many instances purpose built buildings were designed by architects. William Wardell was well established in private practice in Sydney when he designed the new Convent and School, Kew, Victoria, for the FCJ Sisters, in the late 1880s. Building commenced just before the crash of Marvellous Melbourne. Less than half of the total concept of Wardell’s original plan was built. It opened for business in April 1891. Today this building forms the heart of the contemporary Genazzano FCJ College Kew. Many histories intersect in this commission. The vision for Catholic education in Victoria in the late 19th century is critical. The FCJs charism and their experience of teaching in Europe, in France, England, Ireland, Italy and Switzerland, provides a model for their work in Australia. At this time the importance of architecture to society is made manifest in education and its demands on building: if learning is valued then buildings should reflect this, for public buildings can shape morality. Wardell was trained as a Gothic Revival architect and his building participates in a broader medieval and Gothic tradition. Wardell’s original plan for this late Victorian Gothic style asymmetrical three-storeyed building, was designed to integrate a convent, school, chapel, and dormitories. This paper considers architectural history from diverse perspectives, educational, social, religious, economic and political, recognising the complexity of this project and the people who played a part in its conception and realisation.

Intelligent energy management in hybrid electric vehicles

The modelling and simulation approach is employed to develop an intelligent energy management system for hybrid electric vehicles. The aim is to optimize fuel consumption and reduce emissions. An analysis of the role of drivetrain, energy management control strategy and the associated impacts on the fuel consumption with combined wind/drag, slope, rolling, and accessories loads are included.

Effects of deformation-induced heating on bond strength of rolled metal multilayer

The bond strength of various metal multilayers produced by cold rolling of metal foils with different thermal conductivity was investigated. Results indicated that under the same conditions of deformation and surface preparation, the metallic multilayer system with low thermal conductivity exhibited relative high bond strength while high thermal conductivity metal system may fail to be roll-bonded together. The relationship between the deformation-induced localized heating and the bond strength were discussed. The deformation-induced localized heating in the low thermal conductivity metal multilayer systems may provide opportunities for achieving a successful accumulative roll bonding or a “cold roll/heat treatment/cold roll” process to synthesize metallic multilayer materials.

Cyclic deformation behaviour of ultrfine-grained aluminium

Ultrafine-grained aluminium was produced by cryo-rolling and their deformation response under cyclic loading was investigated. Shear banding and grain coarsening were recognized as the main damage mechanism reducing their performance under cyclic loading. However presence of precipitates in ultrafine-grained A1 can actively hinder the operation of cyclic softening mechanisms and increase microstructural stability under cyclic loading.

Development of adiabatic shear band in cold-rolled titanium

The evolution of adiabatic shear localization in commercial titanium subjected to heavy cold rolling was investigated. The evolution of the morphology, microhardness, local shear strain, and local temperature increments were systematically studied and estimated. A shear band with about 25m in width was formed and fine nanograins with a range of dimensions varying from 20 to 160nm and had a mean size of about 70nm were observed inside the centre of shear band after 83% cold-rolling. Microhardness test shows that hardness within the shear band is markedly higher than that of the surrounding matrix. The calculated shear strain and maximum temperature increase within the shear band are much higher than that of the overall deformed sample. The initiation of shear localization may depend on geometric perturbation instead of thermal ones.

The effect of skin passing on the material behavior of metal strip in pure bending and tension

The metal strip used in roll forming has often been preprocessed by (tension or roller) leveling or by skin-pass rolling, and as a consequence, may contain residual stresses. These stresses are not well observed by the tensile test, but could have a significant effect on the bending and springback behavior. With the advent of improved process design techniques for roll forming, including advanced finite element techniques, the need for precise material property data has become important. The major deformation mode of roll forming is that of bending combined with unloading and reverse bending, and hence property data derived from bend tests could be more relevant than that from tensile testing.

This work presents a numerical study on the effect of skin passing on the material behavior of stainless steel strip in pure bending and tension. A two dimensional (2-D) numerical model was developed using Abaqus Explicit to analyze the affect of skin passing on the residual stress profile across a section for various working conditions. The deformed meshes and their final stress fields were then imported as pre-defined fields into Abaqus Standard, and the post-skin passing material behavior in pure bending was determined. The results show that a residual stress profile is introduced into the steel strip during skin passing, and that its shape and stress level depend on the overall thickness reduction as well as the number of rolling passes used in the skin passing process. The material behavior in bending and the amount of springback changed significantly depending on the skin pass condition.

Structure and mechanical properties of asymmetrically rolled IF steel sheet

As-received hot-rolled 5.6 mm thick IF steel sheet was symmetrically/ asymmetrically cold rolled at room temperature down to 1.9 mm. The asymmetric rolling was carried out in monotonic (an idle roll is always on the same side of the sheet) and reversal (the sheet was turned 180° around the rolling direction between passes) modes. Microstructure, texture and mechanical properties were analysed. The observed differences in structure and mechanical properties were modest, and therefore further investigation of the effects of other kinds of asymmetry is suggested.

MAAGs: the next generation. A study of the development of medical audit advisory groups and the arrangements for supporting clinical audit in primary care

Background: MAAGs have, historically, been disparate organisations with a lack of central direction, albeit with the same goal: to develop and support the performance of audit in primary care. This goal has been (and is being) achieved in a number of ways all over the country. In the last two years, MAAGs have witnessed many changes in primary care and are adapting themselves to suit these new arrangements at a local level.

Aim: To formalise our knowledge of where MAAGs are going, how they are getting there and the support they are receiving.

Method: A postal questionnaire to the 104 MAAGs in England and Wales, addressing 6 main issues of relevance to the development of MAAGs and the support they are receiving.

Results: At least two MAAGs have dissolved, leaving a possible total of 102 still in existence. Of these, 76 (74.5%) responded to the survey. The composition of the MAAG committee has changed dramatically since the inception of MAAGs in 1990, and staffing levels appear to have risen substantially. MAAGs appear to be more adequately funded by their health authorities than has previously been reported and many are actively seeking additional sources of funding. There is still large variation in levels of MAAG funding. Furthermore, funding is unrelated to the number of GPs or practices served. Security for MAAG staff appears to have been addressed in many areas, with 84% of MAAGs having at least one member of staff on a permanent employment contract. Many MAAGs are developing rolling programmes in an attempt to eliminate the short-sighted approach to the development of clinical audit that has existed since MAAGs were first set up.

Conclusion: Many MAAGs (with the obvious exception of those that have been dissolved) appear to be thriving without central direction or initiative. It is now evident that we were a little hasty in our concerns for the future of MAAGs beyond April 1996. It would seem that many organisations have taken the situation which arose two years ago as an opportunity to grow and develop in ways that may not have been possible within the confines of the Health Circular.

Local laser heat treatment in dual-phase steels

This research deals with processes leading to local strengthening effects in hot-rolled dual-phase (DP) steels. For this purpose, a method was investigated to achieve local strengthening, namely, local laser heat treatment (LHT). DP sheet steels were globally and homogenously deformed with different degrees of prestrains by cold rolling and subsequently locally heat treated by laser. Following this treatment with selected parameters, the microstructure of the surface and cross section of the heat-treated area as well as the mechanical properties were evaluated by light optical microscopy (LOM), scanning electron microscopy (SEM), as well as transmission electron microscopy (TEM), hardness measurement, and tensile testing. It can be stated that with partial heat treatment, local high strengthening can be produced. At lower heat treating temperatures, this effect could be attributed to bake hardening (BH). Increasing the prestrain as well as temperature results in improving the local properties. With increased heat treating temperature, the initial microstructure near the surface is affected. Partial strengthening of DP steels by laser can open up new fields of application for locally using the strengthening effect to only influence relevant areas of interest, thus providing the potential for saving energy and designed the component's behavior.