PURPOSE: To eliminate irregularities in upper and lower temperatures of a material to be treated and to accelerate a cooling speed by forming a gas subpassage between a plurality of guide cylinders, and variously altering a height in which pressure medium gas is brought into contact with the material to be treated by passage switching means.
CONSTITUTION: A valve body 32 of passage switching means 30 is gradually displaced upward to switch the position of the body 32, and a passage of pressure medium gas 7 is switched from a gas main passage 21 to a gas subpassage 22. Then, since the upper part of a material 24 to be treated is brought into direct contact with part of the cooled gas 7, a decrease in a cooling speed is prevented. On the other hand, the gas 7 rising in the subpassage 22 is shorter at its rising stroke than the passage 21, its temperature does not rise even it reaches near the upper end of a second guide cylinder 20, and the passage 2 is nearer to the material 24 to be treated. Thus, a density flow is generated near the upper end of the cylinder 20, and part of the gas 7 in the subpassage 22 flows down into a treating chamber 25 to cool the material 24 to be treated.
| JPH05209255 | HIGH SPEED TOOL STEEL AND COMPOSITE |
| JPS61223106 | PRODUCTION OF HIGH ALLOY CLAD PRODUCT |
NAOI TOSHIKATSU
SUZUKI KAZUYA
