Soumya S. Mohapatra

Experimental Studies on Different Cooling Processes to Achieve Ultra-Fast Cooling Rate for Hot Steel Plate

In the current research, different cooling processes for getting an ultra-fast cooling rate for a hot static plain carbon steel plate are studied. Depending upon the initial surface temperature and the final microstructures of dual-phase steel, the first type of ultra-fast cooling is late ultra-fast cooling, and second type is early ultra-fast cooling. Late ultra-fast cooling is studied by a water spray and air-assisted spray cooling process, and early ultra-fast cooling is studied by air-assisted spray only. The heat transfer analysis on the above cooling processes show that air-assisted spray has an excellent control on the rate of cooling.

Ultra Fast Cooling and Its Effect on the Mechanical Properties of Steel

The objective of this work is to study about the ultrafast cooling of a hot static 6 mm thick steel plate (AISI-1020) by air assisted spray cooling. The study covers the effect of air flow rate and the water impingement density on the cooling rate. The initial temperature of the plate, before the cooling starts, is kept at 900 °C. The spray was produced from a full cone high mass flux and low turn down ratio air atomizer at a fixed nozzle to plate distance. The cooling rate shows that low turn down ratio air atomized spray can generate ultra fast cooling (UFC) rate for a 6 mm thick steel plate. After cooling, the tensile strength and hardness of the cooled steel plate were examined. The surface heat flux and surface temperature calculations have been performed by using INTEMP software. The result of this study could be applied in designing of fast cooling system especially for the run-out table cooling.

Enhancement of Cooling Rate for a Hot Steel Plate using Air-Atomized Spray with Surfactant-Added Water

The objective of the current research deals with the experimental study of an air-atomized spray with surfactant-added water, cooling a 12-mm-thick AISI-1020 stationary steel plate at three different initial surface temperatures (400°C, 600°C, and 900°C). Furthermore, the effects of surfactant concentration and airflow rate on the cooling rate have been investigated. The surface heat flux and surface temperature show a significant improvement in cooling for all three cases of initial surface temperatures when the air-atomized spray was used with surfactant-added water.

Effect of Oxide Layer in the Ultra Fast Cooling of a Steel Plate

This study deals with the effect of oxide layer during ultra-fast cooling of a hot plain carbon steel plate. In the current research, the hot plain carbon steel plates were cooled from an initial surface temperature of 900°C by using air atomized spray at different air pressures. The heat transfer analysis illustrates that during high pressure air atomized spray cooling, the average surface temperature is almost unaffected by the presence of an oxide layer. For better understanding, the plain carbon steel cooling data have been compared with the data obtained during the cooling of a stainless-steel plate.