Thesis (Ph. D.)--University of Sydney, 2008. / Includes graphs and tables. Includes list of publications co-authored with others. Title from title screen (viewed November 28, 2008) Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the School of Civil Engineering. Includes bibliographical references. Also available in print form.

Thesis (Ph.D.) -- McMaster University, 2002. / Includes bibliographical references (leaves 168-178). Also available via World Wide Web.

Y company started in 1988 positioned to be the largest and the most advanced coated steel producer. Y company (includes the plant in China)Owned seven continuous hot-dup galvanizing lines , five continuous pre-painting lines¡A6 cold rolling mills and 2 pickling lines .Y company has become not only the biggest coated steel producer in Taiwan ,Mainland China and South East Asia , but also one of the 15th largest producers of coated steel products in the world. Y company is able to offer a wide range of finished products to meet the needs of our customers one-stop shopping need. Y company is a coated ¡V steel producer which produce hot¡Vdip galvanized coils and pre-painted coils by means of the manufacturing process of pickling ,cold rolling ,hot-dip galvanizing and pre-painting .On recent ten years ,the steel market changes sharply, but Y company keep growing continuously , the key factor is to establish the strategic alliance with F company to replace electroplating steel sheet with hot-dip galvanized in computer cases . This research is studying the experience story, which we have overcame a number of difficulties during the period developed the ¡§replacing electroplating steel sheet with hot-dip galvanized in computer cases ¡¨and ¡§developing environmentally- friendly steel ¡¨. it is a story that the strategic alliance strenghthen organization ¡Fand after organization empowerment ¡Ait made the relationship between the members of the strategic alliance more closely. This story is to show the difficulties and challenges what we face by means of the Narrative Inquiry and hope to achieve the next success for the next opportunity on the basis of meanings from this story .

Along with science and technology gradually make progress, there is no distance between country. WTO world commerce cloggy eliminate, have no frontier's confine to make product and service that almost be obvious everywhere in the world. Under economic liberalization and internationalize affection, make enterprise management no longer confine to one area or single country. Economic globalization impact everywhere in the world. Iron and steel industry can¡¦t also avoid meeting severely impact and change. In 2002, because global economies gradually change better, lead to international steel market demand to grow up quickly. It is fourth season to reach the best. Price appears take on upspring, too. Due to every important manufacturer rob to buy materical each other in the world, appear steel materical demand to exceed supply. At the end of the year 2003, America, European union, mainland China cancel import restriction successively. At the beginning of the year 2004, price of freight, iron ore, coalmine, scrap steel (Steel ingredient) increases largely at the same time. Many countries ensure steel requirement materials at home, so steel importation tariff transfer fall successively. It makes strict confine measure gradually change to loose. Hot Rolled Galvanized Steel Sheet requires mean consumption to grows up 4.4% near five years in the world. Price also rise along with the price of Hot-Rolled Steel Coil is on raise at the same time. Steel market changes quickly like electronic product¡¦s life. Steel industry face structure change and reform management. In the world, all steel industry is toward competition and cooperative style. Industry internationalize brings manufacture and sales mode's changed. Industry protection policy already do not exist. With environment changed quickly, enterprise do the best increase management performance. It just be able to abidingly run and develop. The study chiefly use questionaire as interview style to get information and organize theoretical document to review and research. Let us know Hot Rolled Galvanized Steel Sheet and Prepainted Hot-Dip Zinc Coated Steel Sheet company how to develop in the world now. It is as Yiehphui company for example, explore Hot Rolled Galvanized Steel Sheet and Prepainted Hot-Dip Zinc Coated Steel Sheet industry how to take advantage of limited source and face industry environmental change to upgrade management technique. By industry internationalization working principles, make enterprise management risk asunders and create industry competition advantage. It becomes industry developmental reference. The study shows some conclusions as follows: 1. Materials source need stability and multiplication. It avoid confining provider but have no method to acquire advantaged negotiate. 2. International steel area integrated tendency have already formed. Major company become bigger and bigger can not avoid. Individual company should cooperation or tactic federation at home with same industry company, form area economy magnitude and debases competition pressure. 3. Push and import TPM management system and TSM work safe management system to healthy company operate constitution and attract elitist. 4. Global market runs for springboard as strengthen developmental technology, develop high affixation value product and new product use domain. It aggravates brand impression and difference product to used for seize more market area and market benefit.

The ability to effectively join magnesium alloys to steel will facilitate increased application and use of Mg alloys in the automotive and aerospace industries where joining Mg alloys to steel in order to achieve light weight, versatile and tailored properties in one composite part is highly desirable. The current thesis details (i) the development of a laser brazing technology for joining Mg alloy-interlayer-steel dissimilar metal combinations, (ii) thermochemical analysis of phases formed at the interface of a Mg alloy-steel joint during laser brazing, (iii) the bonding mechanisms in the Mg alloy-interlayer-steel joints using Al-12Si, Ni, and Sn interlayers, and (iv) the mechanism responsible for wetting of steel by molten Mg alloy during the laser brazing. Firstly, a diode laser brazing procedure has been developed for joining AZ31B-H24 Mg alloy sheet to aluminum coated steel sheet using a AZ92 Mg alloy filler wire. The results of this study suggest that feasibility of this process depends strongly on the pre-existing Al-12Si coating layer on the steel sheet that promotes wetting of the AZ92 Mg alloy filler alloy as well as formation of a layer of θ-Fe(Al,Si)3 interetallic compound along the fusion zone-steel interface. The average joint efficiency was 29% with respect to the AZ31B-H24 Mg alloy base metal. Failure occurred when cracks propagated along the intermetallic layer. Secondly, to predict early stage phase formation in the Mg alloy-interlayer-steel system during the laser brazing process, the thermodynamic stability of precipitated phases at the Mg alloy-Ni-steel interface during laser brazing has been evaluated using FactSage thermochemical software. Assuming local chemical equilibrium at the interface, the chemical activity-temperature-composition relationships of intermetallic compounds that might form in the AZ92 magnesium alloy-Ni-steel system in the temperature range of 600-1100 °C were estimated. The addition of a Ni interlayer between the steel and the Mg brazing alloy was predicted to result in the formation of the AlNi, Mg2Ni, and Al3Ni2 intermetallic compounds at the interface depending on the local maximum temperature. This was confirmed experimentally by laser brazing of AZ31B-H24 magnesium alloy and steel sheet with a micro-layer of electro-deposited Ni using AZ92 magnesium alloy filler wire. Bonding between the magnesium alloy and the steel was facilitated by the formation of a transition layer composed of a solid solution of Ni in Fe on the steel followed by a layer of α-Mg + Mg2Ni eutectic. A band of AlNi with different morphologies also formed along the fusion zone-steel interface, but was not directly responsible for bonding. The average joint efficiency was 56.5% with respect to the AZ31B-H24 Mg alloy base metal and 94.8% higher than that of laser brazed joint using Al-12Si interlayer. Thirdly, to study a low melting point temperature interlayer element, the brazeability of AZ31B-H24 magnesium alloy sheet to Sn-coated steel sheet has been investigated. All tensile-shear specimens fractured in the steel base metal well away from the brazed joint. The results showed that while the Sn coating promoted good wetting between the molten filler alloy and the steel sheet, it did not play a role in forming the final bond. Its primary function appeared to be in maintaining a clean, oxide-free steel surface until the molten Mg filler alloy could come in direct contact with the steel surface. Bonding between the magnesium alloy and the steel was facilitated by the formation of two nano-scale transition layers composed of Fe(Al) solid solution on the steel followed by a layer of Al8Mn5 phase on top of Fe(Al) in the fusion zone along the interface. High resolution-TEM analysis showed that an orientation relationships (OR) with low angle of rotation of the matching planes and low interplanar mismatch existed at the Fe(Al)-Al8(Mn,Fe)5 interface. This was found to be responsible for the low interfacial energy density, good wetting and strong interfacial bond observed in this complex dissimilar metal system. Finally, wetting has been characterized by measuring the contact angles of AZ92 Mg alloy on Ni electro-plated steel as a function of measured peak temperature reached during laser heating. Reactions between molten Mg and Ni led to a contact angle of about 86º in the peak temperature range of 618-750 ºC (denoted as Mode I) and a dramatic decrease to about 46º in the temperature range of 824-1020 ºC (denoted as Mode II). Scanning and transmission electron microscopy (SEM and TEM) indicated that AlNi + Mg2Ni reaction products were produced between Mg and steel (Mg-AlNi-Mg2Ni-Ni-Fe) in Mode I, and just AlNi between Mg and steel (Mg-AlNi-Fe) in Mode II. From high resolution TEM analysis, the measured interplanar mismatches for different formed interfaces in Modes I and II were 17% {Mg-AlNi}-104% {AlNi-Mg2Ni}-114% {Mg2Ni-Ni} and 18% {Mg-AlNi}-5% {AlNi-Fe}, respectively. Therefore, it is suggested that the poor wettability in Mode I was caused by the existence of Mg2Ni since AlNi was the immediate layer contacting molten Mg in both Modes I and II and the presence of Mg2Ni increases the interfacial strain energy of the system. This study has clearly demonstrated that the lattice mismatching at the interfaces between reaction product(s) and substrate, which are not in direct contact with the liquid, can greatly influence the wetting of the liquid.

Kyoto University (京都大学) / 0048 / 新制・論文博士 / 博士(工学) / 乙第12650号 / 論工博第4078号 / 新制||工||1547(附属図書館) / 29728 / (主査)教授 辻 伸泰, 教授 落合 庄治郎, 教授 乾 晴行 / 学位規則第4条第2項該当

The aim of this master´s thesis is the design chosen for testing bonded joints on the specified galvanized steel sheet in laboratory conditions and obtaining parameters of bonded joints for application in industrial practice. Basic tests for testing bounded joints were presented in the work. Subsequently, two tests were selected and verified in laboratory conditions. The result of these tests are specific numerical values that were compared with values gained during tests linking method clinch.

<p>In recent years, surface engineering techniques have been developed in order to improve the tribological performance in many industrial applications. In sheet metal forming processes, the usage of liquid lubricants can be decreased by using self lubricated tribo surfaces which will result in more environmentally friendly workshops. In the present work two different concepts, i.e. the deposition of thin organic coatings on the steel sheet and PVD coatings on the tool, have been evaluated. The sheet materials investigated include Zn and 55%Al-Zn metal coated steel sheet, which in general are difficult materials to form under dry conditions since they are sticky and thus have a high tendency to adhere to the tool surface. The PVD coatings include CrN, TiN and various DLC coatings. The work comprises tribo testing and post test characterisation using surface analytical techniques in order to evaluate the tribological properties of the tribo surfaces. The tribological tests of different tribo couples were conducted by using modified scratch testing and ball-on-disc testing. From these test results different friction and wear mechanisms have been identified. </p><p>The deposition of thin organic coatings on the steel sheet metal has been found to be promising in order to control the friction and to avoid metal-metal contact resulting in galling. However, it has been found that the tribological characteristics of organic coated steel sheet are strongly influenced by coating chemical composition, the substrate surface topography and the coating thickness distribution. </p><p>The performance of the PVD coatings depends mainly on the chemical composition and topography of the coated surface. By choosing PVD coatings such as diamond like carbon (DLC) low and stable friction coefficients can be obtained in sliding contact against Zn. Surface irregularities such as droplet-like asperities may cause an initial high friction coefficient. However, after a running in process or by polishing the PVD coating low friction coefficients can be obtained resulting in a stable sliding contact. </p><p>The combination of imaging (optical profilometry, LOM, SEM) and chemical analytical techniques (EDS, AES, ToF-SIMS) gave valuable information concerning the friction and wear properties of the tribo surfaces investigated.</p>

In recent years, surface engineering techniques have been developed in order to improve the tribological performance in many industrial applications. In sheet metal forming processes, the usage of liquid lubricants can be decreased by using self lubricated tribo surfaces which will result in more environmentally friendly workshops. In the present work two different concepts, i.e. the deposition of thin organic coatings on the steel sheet and PVD coatings on the tool, have been evaluated. The sheet materials investigated include Zn and 55%Al-Zn metal coated steel sheet, which in general are difficult materials to form under dry conditions since they are sticky and thus have a high tendency to adhere to the tool surface. The PVD coatings include CrN, TiN and various DLC coatings. The work comprises tribo testing and post test characterisation using surface analytical techniques in order to evaluate the tribological properties of the tribo surfaces. The tribological tests of different tribo couples were conducted by using modified scratch testing and ball-on-disc testing. From these test results different friction and wear mechanisms have been identified. The deposition of thin organic coatings on the steel sheet metal has been found to be promising in order to control the friction and to avoid metal-metal contact resulting in galling. However, it has been found that the tribological characteristics of organic coated steel sheet are strongly influenced by coating chemical composition, the substrate surface topography and the coating thickness distribution. The performance of the PVD coatings depends mainly on the chemical composition and topography of the coated surface. By choosing PVD coatings such as diamond like carbon (DLC) low and stable friction coefficients can be obtained in sliding contact against Zn. Surface irregularities such as droplet-like asperities may cause an initial high friction coefficient. However, after a running in process or by polishing the PVD coating low friction coefficients can be obtained resulting in a stable sliding contact. The combination of imaging (optical profilometry, LOM, SEM) and chemical analytical techniques (EDS, AES, ToF-SIMS) gave valuable information concerning the friction and wear properties of the tribo surfaces investigated.

Deformation and annealing texture in the cold rolled low carbon steels is important for sheet metal forming operations and service performance. The aim of this study is to non-destructively investigate the effect of texture on magnetic anisotropy. Various samples having different textures and residual stress states, due to different % reduction in thickness, annealing and stress relieving treatment, were prepared. Texture maps were obtained by Magnetic Barkhausen noise measurements performed with 100 steps between the ranges of 00-3600 on the surface. Microstructure investigation by optical &amp / scanning electron microscopy / hardness and tension tests were performed / and texture was determined by X-Ray diffraction method. The results were compared, evaluated and discussed to establish relationship between texture and magnetic Barkhausen Noise emission.