| 摘要 |
PURPOSE:To provide uniform hardness and uniform thickness of a hardened layer over the entire surface to be hardened by flushing the flow of a cooling fluid at a high flow rate parallel with the surface of a member to be heated in one direction so as not to provide time for forming vapor film of the cooling fluid on the member surface. CONSTITUTION:A shaft body W to be heated is supported on the ridgeline at the tips of the plural fins 31 embedded on the inside circumferential wall in a cooling chamber 3 and is held concentrically with the inside circumferential wall at a slight space alpha therefrom. Both end faces of the body W are brought into tight contact with the backing plates 7a, 7b having the same diameter as the diameter of the body W supported by supporting members 71. A cooling fluid is then admitted through a feed pipe 4 into the 1st chamber 1 and is flushed through the space of the cylindrical chamber into the 2nd chamber 2. Then the entire surface of the shaft W is exposed to the cylindrical flow of the cooling fluid parallel along the surface and is subjected to quick cooling simultaneously with starting of cooling without having the time for formation of vapor film. The chamber 2 is displaced by driving of a cylinder 5 at the time when the body W is hardened and cooled and the body W is removed from the chamber 3. |
