الفهرس 
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Abstract
The aim of this work is to improve the mechanical properties for hot rolled steel wire by grain refinement achieved by controlling the cooling patterns after final deformation stage of rolling process. This can be achieved through understanding the treatment processes of rolled products, This processes had been divided according to the stage to which it is applied, a comparison table illustrates the applied processes prior to rolling, during rolling, post rolling and the secondary processes off-line were established. An investigation of the temperature gradient along the rolling line had been carried out b applying computer program to calculate rolled stock temperature. A study for the effects of changing water and air cooling parameters either individually or combined on the mechanical properties and micro-structure for low, medium and high carbon steels had been conducted. A study of the effect of varying the order of blown air intensity on Stelmor conveyor with constant water cooling rate and the effect of changing Stelmor conveyor speed on the mechanical properties for different sizes and grades of steel had been studied.Finally a comparison between the effectiveness of controlled cooling and tempcore technique had been conducted. The thesis starts with an introductory Chapter (I) presenting the concepts of controlled rolling and controlled cooling technique (On Line Accelerated Cooling - OLAC). A critical review of controlled cooling technique for the optimum micro-structure characteristics, a special cooling technique of tempcore and Infrasonic technologies had been presented. Chapter (II) includes a description of the ROD Mill in Alexandria Iron & Steel Company (ANSDK) where all the experimental work had been applied.Chapter (III), describes the plan and procedures of the experimental work for low, medium and high carbon steels including the sampling plan, position from the rolling line, samples preparation procedur and specifications of the used equipment for applying mechanical testing Chapter (IV) under the title of RESULTS AND DISCUSSION describes starting with the temperatun distribution along the rolling line, a computer program used to calculate the temperature gradient for the rolled stock. This computer program considers the heat generated related to hot deformation and heat loss due to conduction, radiation and convection. Finally a study for the micro-structure evolution along the rolling line starting from the re-heating thrnace till the end of Stelmor conveyor had been conducted. Incrasing water and air cooling rates either individually or combined to improve yield and tensile strength as well as ductility for all steel grades mutually with grain refinement and increasing pearlite content for the formed ferrite - pearlitic structure, which is the main goal of applying controlled coolin technique, at the same time steel of higher carbon content is more affected with water than air cooling Addition of water cooling to sole air cooling prove to be more effective than addition of air to sole water cooling for yield and tensile strengths., while yield strength is affected with cooling rates more than tensile strength.