A. V. Sverdlin, A. R. Ness, Bradley University, Peoria, IL
AHTF furnaces, in which air or gas is heated to 500-700oC without electrical or other special heaters, have been developed and placed in operation in a number of plants for heat treating aluminum, magnesium, and titanium alloys, and also steels. The AHTF chamber furnace is thermally insulated without the use of fire bricks. It has a centrifugal fan with vanes having a special contour. The fan, operating in a closed system, converts, into heat, almost all the energy used to turn it; the heat is transferred to the parts by convection. In most machine building plants aluminum alloys are heat treated in ERF furnaces (electric resistance furnaces with forced air circulation) or in salt baths. This research deals with an investigation of the heating conditions for various semifinished products of aluminum alloys in the AHTF-3 in comparison with the ERF-2 furnace and a potassium nitrate bath of approximately the same working volume
Summary: - The AHTF is more economical, simpler to manufacture, and safer in operation than electric air furnaces or salt baths.
- The AHTF produces a more uniform temperature in the working space and heats the air from room temperature to the given temperature twice as rapidly as ERFs.
- Heating of different semifinished products with sections 40-200 mm thick in loads of 80-350 kg to 500-515̊C is 1.8-2.5 times more rapid in the AHTF-3 than in the ERF-2 with similar dimensions in spite of the fact that the ERF has twice the power.
- The mechanical properties, resistance to corrosion and stress corrosion, and electrical conductivity of various semifinished aluminum alloy products are the same after heat treatment in the AHTF-3, ERF-2, and the salt bath.
