Optimization of the Practice of Slow Cooling Steel Bars: A Redesign and Modernization of Materials

Throughout the process of steel making, certain grades of steel are a higher risk for defects caused by the inability to quickly diffuse hydrogen through the steel when cooled to room temperature at a normal rate based on the ambient air temperature. To reduce the hydrogen flaking defects that are caused due to hydrogen entrapment in the steel, the process of slow cooling is utilized. This process reduces the cooling rate of steel bars by keeping them at a higher temperature for extended periods and in turn gives the hydrogen a chance to fully dissipate from the steel. In many steel mills, this process is completed using insulated boxes, however in the mill where this project is based, this is not a possibility. Storage and space issues mandate that slow cooling occur outdoors and be completed by materials that are easily managed by employees which does not allow for slow cooling to be done in insulated boxes, as the boxes would need to be heated during the winter months and stored when not in use. Additionally, the initial cost of the boxes poses an issue for the company, as fifty boxes would have to be purchased to accommodate for the maximum number of heats the company can slow cool at once. Different materials and fabrication styles were then studied based on the following requirements. First, the materials must increase the safety for employees. Secondly, the materials need to improve or retain the quality of the steel bars. Finally, the materials need to reduce the amount of waste created by the process. Due to these requirements it was determined that a new material system, specifically Material 1, was the best solution due to its inability to absorb water, weight, ease of use, and improvement in worker safety without increasing costs to the company