| 摘要 |
A process and apparatus are disclosed for manufacturing high strength low alloy (HSLA) flat rolled steel products having high yield strength and formability . A preferred process comprises the formation of an as-cast product; reducing th e thickness of the as cast product in a roughing mill; holding the temperature of the rough-reduced product at a temperature sufficient to permit substantially complete recrystallization of austenite grains in the rough-reduced product; followed by a final reduction step in a hot rolling strip mill. In this process, there is little or no precipitation of microalloy until after the material passes through the stri p mill and therefore the material being rolled is relatively soft compared to known processes. Therefore, less power is required to roll the material to its final dimensions, with a corresponding improvement in dimensional control. The material produced according to this process has a strength of at least about 70 ksi, more preferably at least about 80 ksi, and a formability as measured by n-value within the range of from about 0.1 to about 0.15. |
