New high strength large diameter pipe steels
Accelerated cooling after rolling represents a further development of the thermomechanical treatment designed to optimize alloying. In 1983, after extensive test series, a system for accelerated cooling—the Mannesmann Cooling System (MACOS)—was built at the Mülheim plate rolling mill. The design and control principles of this system are described, and the layout is schematized. The principle of using top and bottom water curtains ensures uniform cooling, even in the case of extreme plate widths. All system functions are controlled and monitored via a process computer. Using the production of a steel3-the GRS 550 (X 80), characterized by 0.08% C, 1.9% Mn, 0.04% Nb and 0.02% Ti—as an example, the reliability of this new combined method—TM MACOS—is verified.
KeywordsFerrite Bainite Pearlite Weld Metal Niobium Carbide
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