Optimization of Steel Sheet Bar Gauge

In order to manufacture products, various manufacturing specifications are necessary to be determined in advance. To manufacture cold-rolled steel sheets, as an example, specifications, such as additive elements, rolling conditions, heat treatment conditions, have freedom of choice. And they have to be properly determined, considering various conditions and restrictions. More concretely, manufacturing specifications are usually determined through laboratory experiments or trial manufacture at actual processes, considering their influences on quality, cost, and production throughput of products. As changing manufacturing specifications usually give influence on quality, cost, and production throughput of products, it is not easy to change them according to the conditions such as the amount of in-process inventory, change of production cost or production requirements, and so on. This paper presents a new approach to promptly determine manufacturing specifications, by analyzing and quantitatively modeling relations between manufacturing specifications and indices of estimation for consequent manufacture, and selecting manufacturing specifications for realizing optimum indices of estimation. This approach is applied for determining bar gauge, thickness of hot-rolled coils, for manufacturing cold-rolled steel sheets, and improvement of production is realized by adapting to the changes of requirements and circumstances of production.