Passivation, local anodic depassivation and pitting corrosion of stainless steels in bulk and under thin phase layers of acid sulphate and neutral chloride solutions have been studied. A number of electrochemical, chemical, metallographic and physical techniques were employed in this study. The choice of stainless steels, test solutions and methods of investigations was based on scientific expediency and practical availability. For the first time in electrochemical and corrosion characteristics of passivation, local anodic depassivation and pitting corrosion of stainless steels were obtained in thin layers and compared with those in bulk electrolytes. It was demonstrated that the thickness of the electrolyte layer can influence the passivation process and, under certain conditions, the kinetics of pitting erosion. Several tests were conducted and results given. It was shown that the prognosis of corrosion behaviour of some stainless steels in sulphur dioxide contaminated atmosphere based on electrochemical measurements in bulk electrolytes can be erroneous. The same measurements carried out in thin phase layers enable more accurate prediction. However, the prognosis of the relative resistance of the stainless steels to pitting corrosion in the clean chloride-containing atmosphere may be based on conventional electrochemical measurements in the bulk of corresponding electrolytes / Doctor of Philosophy (PhD)

Thesis (Ph. D.)--Oregon Graduate Center, 1980.

Thesis (Ph. D.)--Oregon Graduate Center, 1979.

In contrast to traditional stamp shaping techniques, tube hydroforming is a realively new shaping technique. But there are still a lack of engineering parameters, mold designs data bases and technique knowledge in this area. This research conducts various tube hydraulic bulge forming experiments, using hydraulic bulge forming testing machines. The pressure and bulge height for UNS C26800 zinc-copper tubing and AISI 1215 carbon steel tubing are measured. The above data are substituted into a hydraulic pressure bulge mathematic model to derive UNS C26800 zinc-copper and AISI 1215 carbon-steel tubes flow stress parameters of initial yielding stress £m0¡Bcoefficient K value and contingency index n value. Moreover, tensile test of the above materials are conducted to the material¡¦s £m0¡BK and n values. then proceed with a comparison of the two sets of statistics. In bulge tests, UNS C26800 zinc-copper tube annealed with temperatures of 300¢J and 500¢J and the not-yet annealing AISI 1215 carbon-steel tube without annealing are used. Additionally, finite element package software is used to simulate the bulge-height and forming pressure. From the comparisons of experimental and analytic results, the deformation mechanisms of tube during the bulge-shaping discussed.

This thesis seeks to understand the causal factors of deindustrialization in the steel industry during the late twentieth century and uses the former Atlantic Steel Company mill in Atlanta, Georgia as a case study. Using company records and secondary sources from a variety of social science disciplines, I explore the roles of neoliberalism, government foreign and domestic policies, and the world economic crisis of 1973 to reassess contemporary understanding of the concept of deindustrialization.

As a whole the steel industry in Taiwan has become relatively mature from a highly growing industry in the past till facing slow down in demand recently. Its growing rate has been decreasing gradually. During the past two years, the growth was decreasing following the saturation of the domestic market. On the other hand, the Mainland China has a strong demand on steel due to its rapid economic development, and has become an important export market for the steel industry in Taiwan. The strong demand from the rapid growing China market can absorb the extra production capacity of the downstream steel industry in Taiwan which is facing a bottleneck in the domestic market. The present study is aimed to research the following issues: 1. Strategy and competitiveness of steel industry in Taiwan; and 2. Taiwan steel companies¡¦ investment in China. The main conclusion obtained I the present study includes: 1. Shareholders structure of steel companies in Taiwan has affected decision making for investment in China. 2. The domestic market for steel in Taiwan has been saturated. 3. China is an opportunity for Taiwan steel industry. 4.Taiwan steel industry invested a lot and built steel mills in China, mostly during 2002 and 2003.

The objective of this thesis is to analyze the power harmonic distortion of a steel factory and to mitigate the distortion by passive filters. The mathematical harmonic model of the industrial power system is built according to the power system network and the substation load characteristics of the steel factory. The substation load is converted as equivalent impedance, the harmonic voltage and harmonic current, and the total harmonic distortion of bus voltages and currents are then derived by the harmonic load flow analysis with the actual harmonic current data of the converters, cycloconverters, and VVVF in the plant. Due to the dynamic load behavior the stochastic harmonic current generated by various components is varied with the operation modes of all plants. To investigate the harmonic distortion of the steel factory with statistics oriented manner, the stochastic harmonic load flow analysis is executed to find the 95% confidential interval of system harmonic distortion.By this way, the effectiveness of passive filters for mitigation of harmonic distortion can be evaluated more accurately as compared to the conventional harmonic load flow analysis.

The diffusional transformation kinetics of C-Mn steels during continuous cooling have been measured and predicted in this study for predicting the non-isothermal multi-stage cooling transformation kinetics. A suitable thermodynamic model is assessed for determining the driving force of austenite to ferrite transformation and the austenite/ferrite interface concentrations under various equilibrium constraints, which are essential to determine the diffusion-controlled transformation kinetics. The continuous cooling transformation (CCT) curves of C-Mn steels are determined using dilatometric method. Pham¡¦s empirical growth model is found most suitable for describing the start and finish transformation curve. The Avrami equation, common-used for isothermal transformation, is found to be applicable to the continuous cooling transformation. The Avrami exponents, nF and nP, for ferrite- and pearlite- dominant CCT, respectively, are close to the isothermal ones reported in the literature. The Avrami constant, b, increases with decreasing austenitizing temperature, indicating a fast progress of transformation. Combining Pham¡¦s empirical growth model with Avrami equation, the CCT kinetics of C-Mn steels can be predicated well. The examination on the microstructural evolution during CCT suggests that the transformation of austenite to grain boundary allotriomorphs of ferrite (GBAF) can be divided into (1) nucleation and growth (NG) stage, (2) growth only (site saturation, SS) stage, and (3) coalescence stage. In the NG stage, the oblate ellipsoid aspect ratio of GBAF remains 3:1 until all the nucleation sites are exhausted., i.e. the onset of SS stage, then gradually decreases in the SS stage. Once the aspect ratio approaches unity, the coalescence starts to operate. Based on this observation, a physical base model is developed for predicting the austenite to GBAF CCT. This model possesses the capability to predict the start and finish transformation temperatures, the fraction transformed, and the final ferrite grain size. Although such model failed to predict the whole range of CCT curve due to the fact that only the GBAF transformation is included at present stage, it is still highly recommended for microstructural control. In order to completely predict the whole CCT curves, a semi-empirical physical base model is adopted. In addition, the methodology to predict multi-stage cooling transformation from CCT curves is also derived based on additivity rule and the concept of ideal TTT diagram. Associated with the additivity rule and the concept of ideal TTT diagram, such empirical model is validated to be applicable for the prediction of CCT and step wise cooling transformation. The latent heat is calculated using thermodynamic software for the accurate control of cooling history of the medium carbon steels which usually releases an abundance of latent heat. Associated with the semi-empirical transformation model, the calculation of latent heat is integrated into a heat transfer model and successfully implemented in a mill operation.

Since Taiwan and China have become the members of the World Trade Organization in the year of 2002, many companies are gaining various opportunities while meeting the challenges of unpredictable and fast-paced markets. China Steel Global Trading Corporation (CSGT), which is responsible for the international business of China Steel Corporation (CSC) Group, should take these opportunities to broaden the overseas market, especially in China. As the international trading brain and strong arm of the CSC Group as well as the export exclusive agent of China Steel Corporation and China Steel Aluminum Corporation, CSGT has built its international marketing network after 5 years¡¦ efforts. CSGT take the advantages of image, technique, marketing and finance of CSC Group and has been deeply trusted by the foreign customers and suppliers. Through the strength and resource advantages of CSC Group and steel industry, CSGT is going to diversify to other industry materials, consumer goods or others in the coming future. CSGT also has the vision to turn into a worldwide and whole-wise trading company by cooperating with other company in different fields. The thesis is about how to fully utilize the resource of CSC group to rebuild the competitive strategies while environmental challenge and structured chaos, to set up the sustainable competitive advantages and core competence, to reach the vision of CSGT. With the intersectional brain storming we reviewed the strength, weakness, opportunity, and threat of CSGT, found out the core competence, adopted the strategy alliance , rebuilt the value chain and new competitive positioning. Finally we come to the vision of Great Trading Firm ¡Xthe Eternal CSGT Builds the Last.

Abstract IF steel with two grain sizes ( 70£gm and 210£gm ) strain amplitude of 2%¡B1.6%¡B1%¡B0.8%¡B0.6%¡B0.4%¡B0.3%¡B0.2%¡B0.1%¡B0.05% were fatigued in order to obtain basic fatigue properties. By use TEM , we can know that we can observe dislocation cells from £G£`t = 0.05% ~£G£`t = 2% . When £G£`t > 1.6% , hardening will occur , if not , softening will be observed . The more strain amplitude is , the more plastic deformation will be observed . When£G£`t > 0.3% , the elastic deformation will smaller than plastic deformation . When£G£`t =0.2% ~£G£`t = 0.4% , we can observe secondary hardening from the specimen of 70£gm . When £G£`t > 1% , the n¡¦ of 70£gm is more than the n¡¦ of 210£gm , that means the specimen of 70£gm has bigger hardening . By the ¡¥ Stress amplitude v.s. Plastic deformation amplitude ¡¦ plot of 70£gm and 210£gm , we can know that there is no ¡¥ pleatue ¡¦ . The more strain amplitude is , the more difference between long axis and short axis of dislocation cell will occur .