Improvements in or relating to the continuous heat treatment of moving elongate metal material

摘要

Moving elongate metal material such as mild steel strip or wire 8 is continously heat treated by circulating liquid heat transfer medium 12 around a closed loop path, passing the material through the medium, e.g. over guide rollers 6 and 7 in chambers 2 and 3, along a portion of the path, e.g. through duct 5, in a direction opposite to that in which the medium moves, and applying heat uniformly to the medium moving along the path portion to produce similar temperature characteristics for the material and medium therealong. Preferably the medium is an electrically conductive liquid such as molten lead, Pb-Bi or Pb-Sb alloy or molten salts of Ba, and is heated by a transformer heating arrangement 11 energized from a H.F. power supply e.g. 500 c/s., at least part of its secondary circuit being formed by the medium to be heated. The medium may be circulated by a paddle wheel 9 mounted across the chambers above their partition member 4, Fig. 1, or by an electromagnetic pump 91 in a pipe 13 extending between the chambers, Fig. 2. A short-circuiting bar 15, Fig. 2, may connect the chambers to complete the secondary circuit of the transformer. Baffle members 10, Fig. 1, may be located in the chambers.