To provide a metal heat treatment device applying hot gas which is capable of efficiently and reliably performing the heat treatment requiring isothermal maintenance such as austempering, multi-temper and multi-quench without using a salt bath.
In the metal heat treatment device, a circulation passage to communicate with a work storage part 2 is branched into a first passage (for high temperature) F1 and a second passage (for low temperature) F2, and the output temperature of mixers 6 provided at terminating positions of the first and second flow passages is controlled to the intermediate temperature (the hot gas temperature) while adjusting the opening of control windows 23 provided in both flow passages. Blower devices 9 and 10 are provided on both flow passages, a heat accumulation type heat exchanger 4 having a heat accumulation material is provided on the first flow passage, and a cooling heat exchanger 5 capable of performing the cooling to normal temperature is provided on the second flow passage.
Iwa Saki Kokuni
Akira Kurihara
Kawamata Sumio
Koji Okazaki
Masakazu Ito
Shunichi Takahashi
Toshio Takamatsu