Method and apparatus for heat treatment of material to be worked on, especially of aluminum alloys or magnesium alloys

Apparatus for heat treatment of a metal piece or metal pieces to be subsequently worked on, such as ingots, billets, rods tubes, cast strips and cast billets, especially of aluminum or magnesium alloys, wherein the pieces are preheated and thereafter held at a predetermined heat treatment temperature for a predetermined time, each of the pieces having a diameter,

• comprising in combination:
• a pretreatment furnace including a heating device having flame producing burners and being operable to heat the pieces using direct flame impingement, the flames being at a temperature higher than the heat treatment temperature;
• a heat treatment furnace including heating means for providing hot gases and forced circulation of the hot gases, said heating means having a temperature control device for adjusting and maintaining the temperature of the hot gases;
• and
• transport means comprising a pretreatment transport device and a treatment transport device movable in a transport direction, said pretreatment transport device being operable to move the pieces at a pretreatment speed through said pretreatment furnace, and said treatment transport device being operable to move the pieces at a treatment speed through said heat treatment furnace, said treatment speed and said pretreatment speed being independently variable and including means for stop-and-go motion, means for stepwise motion, and means for continuous motion, said transport device including
• a plurality of stationary beams, each of the beams being formed with a plurality of sawtooth-shaped depressions, each of the depressing having a bottom for receiving the pieces, and being at least partly defined by an oblique surface relatively slightly inclined with respect to the transport direction;
• and
• a plurality of lifting beams disposed between the stationary beams, respectively, movable from a rest position below said lifting beams in a lifting direction, and independently thereof also in the transport direction, each of the lifting beams having a flat surface and a plurality of prismatic guards disposed on said surface at respective distances, each of said distances exceeding the diameter of each of the pieces, said pieces being liftable from said depressions by said lifting beams and lowerable on the oblique surfaces of the succeeding depressions, respectively, as viewed in the transport direction, said pieces being thereupon freely rollable into the bottom of said depressions, said lifting beams being contactable by said pieces upon the latter being disposed in said depressions, and subsequently movable in a controllable manner in a direction opposite to the lifting direction.

Apparatus for heat treatment of a metal piece or metal pieces to be subsequently worked on, such as ingots, billets, rods, tubes, cast strips and cast billets, especially of aluminum or magnesium alloys, wherein the pieces are preheated and thereafter held at a predetermined heat treatment temperature for a predetermined time, and each piece has a longitudinal axis,

• comprising, in combination:
• a pretreatment furnace including a heating device having flame producing burners and being operable to heat the pieces using direct flame impingement, the flames being at a pretreatment temperature higher than the heat treatment temperature using direct flame impingement against the separated pieces;
• a heat treatment furnace including heating means for providing hot gases and forced circulation of the hot gases, said heating means having a temperature control device for adjusting and maintaining the temperature of the hot gases;
• a transport means comprising a pretreatment transport device and a treatment transport device, said pretreatment transport device being operable to move the pieces at a pretreatment speed through said pretreatment furnace and said treatment transport device being operable to move the pieces at a treatment speed through said heat treatment furnace;
• said treatment speed and said pretreatment speed being independently variable and including means for stop-and-go motion, means for stepwise motion, and means for continuous motion, and
• a cooling station arranged downstream of said heat treatment furnace, provided with means for rotation of each of the pieces about its longitudinal axis, said means for rotation comprising roll pairs, each roll pair having two rolls, the two rolls of each roll pair forming a prismatic seat for supporting the pieces, at least one of the two rolls of each roll pair being drivable.