Study On Rolling Process And Heat Treatment Of EH36 High Strength Ship Plate

With the fast development of shipbuilding industry, the demand of high strength hull plate is more and more, and it brings lots of chance to the China iron and steel industry. Many new medium plate production lines have been built to supply the demand. The subject was investigated on high strength hull plate steel, the composition design according to the fundamental of Low-Carbon High-Manganese and Nb, Ti-microalloyed. Applyed three kinds of product technics in rolling processing, In order to get super performance of strength and toughness heat-treatment the rolled plate. The main studies are shown as follows:1. CCT curve is measured by hot simulation experiment, the influences of cooling speed to ship plate steel are gained by analyzing these deferent parameters. The mensuration of the relation of growing up austenitic and time and the ralation of growing up austenitic and temperature. Then feasible process parameters are defined by laboratory data.2. According to the results of hot simulation experiment, optimized the process technologies of high strength hull plates. Analyze the different processing parameters of the three different thickness plates. Selected three kinds of thickness (20mm,30mm,40mm) And applyed three kinds of product technics in rolling processing,found that the rolling types of CR and TMCP of tensile and impact are super than AR.3. The relation between processing and properties for EH36 of heat treatment is analysed, which was found is with the increase of heat temperature and time of heat preservation, the impact properties are best than before, but the opposition of the tensile properties have not notability improve.4. According to the industrial trial manufacture, the technics of TMCP can be applied to meet the requirements of Association Classification Societies.5. According to the fundamental of Low-Carbon High-Manganeseand Nb-microalloyed designed the chemical constitutions of EH36 which satisfied the needs of factory, and the high strength hull plate super performance are produced. The technics of CR:the heating temperature is 1200℃;and the opening rolling is 1100-1150℃;the second opening rolling 860-910℃; the finishing temperature of finish rolling is 810-850℃; then adopted cooling under the air or water. Cooperated with heat treatment, attained to eligibility high ship plate.Appled the normalizing technics for thick high ship plate, the better heat temperature is 910℃and the time of heat preservation is 1.7-2min/mm.