Gas Cooling – Is Pressure or Velocity Most Important?

This paper presents the results of a study examining the cooling rates of two vacuum high-pressure gas quenching furnaces: a large 10-bar furnace equipped with a 600-hp blower motor and a smaller 10-bar furnace with a 300-hp motor. In comparing critical cooling temperatures for H13 in the 1850°F to 1300°F range, the furnace that is almost three times larger in volume (110 vs. 40 ft³ of hot zone) cooled the same workload almost identically to smaller unit. The test results clearly show that gas flow, or velocity, is more meaningful than pressure when it comes to cooling rate.