Method and apparatus for quenching

摘要

A quenching method wherein an object to be quenched is sprayed with a mixed spray jet of a liquid and a gas. The diameter of droplets in the mixed spray jet is from 50 to 200 mu m, and the mixing ratio between the liquid and the gas is varied during the period from the start to the end of cooling. Also disclosed is a quenching apparatus having nozzles for spraying an object to be quenched with a mixed spray jet of a liquid and a gas, a liquid supply source for supplying a pressurized liquid, and a gas supply source for supplying a pressurized gas. Each of the nozzles has a liquid-jetting port formed in the surface opened to the atmosphere and a gas-jetting port annularly formed around the liquid-jetting port on the same plane. The liquid-jetting port is communicated with the liquid supply source, while the gas-jetting port is communicated with the gas supply source. A flow rate regulating valve for regulating the flow rate of the pressurized liquid is disposed between the liquid-jetting port and the liquid supply source, while a flow rate regulating valve for regulating the flow rate of the pressurized gas is disposed between the gas-jetting port and the gas supply source.