Metallurgy and heavy engineering construction, which are considered the most energy-intensive industries, place great focus on complex shaped thick-gage plate metal items of equipment with wall thickness exceeding 40 mm and diameter/width of up to 4000 mm. Such items of equipment include large machine parts manufactured by means of hot plate stamping, such as bodies of rotation (for example, the segment of the radial surface of converter shell, the bottom part of degassing unit, etc.) utilized as pressure-operated devices, vessels, tanks and other facilities by metallurgical, petrochemical, oil and gas, and nuclear industries. Presently known manufacturing methods of such items of equipment, for instance, stamping methods, have a number of technological problems. In the present paper, creation and development of the theory and technology of manufacturing different large bodies based on the combination of plate rolling and stamping processes, as well as the combination of asymmetric rolling and plastic bending processes, are proposed. The goal was to develop a cost-effective technology of producing large-size bodies of rotation in the conditions of a thick-plate mill. The rolling of the package forms the basis of the first stage of the new process. The package consists of the upper (punch) base, the lower (matrix) base, and the blank plate situated between them. The economic benefit from installing the developed technology based only on the combination of asymmetric rolling and plastic bending processes was more than 1 million dollars. Casings on two converters were produced and installed in the oxygen-converter plant.
PcrA Helicase and the Mechanism of Asymmetric Rolling Circle DNA Replication