Device and Method for Water Spray Quenching

Abstract

The invention relates to a device for water spray quenching that includes (i) a quenching chamber designed and set up to receive metallic workpieces, with a batch of volume V0 of 0.045 to 3.5 m3 and (ii) at least one atomizer which is configured to atomize water in air or nitrogen and is fluidically connected to the quenching chamber; in which the at least one atomizer and the device are designed and set up to generate a spray mist with a water content of 2.5 to 40 vol. % and a Sauter mean diameter of 20 to 2000 m and also a spray mist flow through the batch volume V0 of 0.05 to 25 m3/s.

1 . An apparatus for water spray quenching comprising
 a quenching chamber which has been designed and set up to accommodate metallic workpieces and has a charge volume (V 0 ) of 0.045 to 3.5 m 3 ; and   at least one atomizer which is configured for the atomization of water in air or nitrogen and is fluidically connected to the quenching chamber;   wherein the at least one atomizer and the apparatus are designed and set up to generate a spray mist having a water content of 2.5% to 40% by volume and a Sauter diameter of 20 to 2000 μm and to convey a spray mist flow through the charge volume V 0  of 0.05 to 25 m 3 /s or to recirculate the spray mist in the charge volume V 0  at a spray mist volume flow rate of 0.05 to 25 m 3 /s.   
     
     
         2 . The apparatus as claimed in  claim 1 , wherein said apparatus is designed and set up to generate a spray mist throughput between an inlet and an outlet of the quench chamber of 0.05 to 25 m 3 /s. 
     
     
         3 . The apparatus as claimed in  claim 1 , wherein said apparatus comprises a first and second atomizer, each having 3 to 60 atomizer nozzles. 
     
     
         4 . The apparatus as claimed in  claim 3 , wherein outlets of the atomizer nozzles of the first atomizer are disposed in a first horizontal plane, outlets of the atomizer nozzles of the second atomizer are disposed in a second horizontal plane, the quench apparatus comprises one or two receptacles for a first and second charge carrier, and the first and second receptacles are disposed in vertical direction between the first and second horizontal planes. 
     
     
         5 . The apparatus as claimed in  claim 3 , wherein the atomizer nozzles of the first and second atomizers are each designed, configured and arranged in space to subject a horizontal area of 0.16 to 2.25 m 2  uniformly to water spray mist. 
     
     
         6 . The apparatus as claimed in  claim 5 , wherein the atomizer nozzles of the first and second atomizers are independently designed, configured and arranged in space to subject a horizontal area of 0.16 to 2.25 m 2  uniformly to water spray mist in such a way that a vertical component v z  of a flow rate of the water spray mist has a value of 0.8×v z  to 1.2×v z  with 0.5 m/s≤v z ≤35 m/s. 
     
     
         7 . The apparatus as claimed in  claim 1 , wherein the quench chamber is equipped with one or more ventilators or fans having a spray mist volume flow rate of 0.05 to 25 m 3 /s. 
     
     
         8 . The apparatus as claimed in  claim 1 , wherein said apparatus comprises at least one recirculator which is fluidically connected to the quench chamber and has a recirculation drive, where the recirculation drive is set up to generate a spray mist volume flow rate of 0.05 to 25 m 3 /s. 
     
     
         9 . The apparatus as claimed in  claim 1 , wherein said apparatus comprises an electronic controller and at least one infrared sensor, the at least one infrared sensor is designed and set up to measure the temperature of workpieces disposed on a charge carrier when the charge carrier is being held in a charge carrier receptacle of the apparatus, and an electrical output from the at least one infrared sensor is connected to an electrical input of the electronic controller. 
     
     
         10 . The apparatus as claimed in  claim 1 , wherein the quench chamber comprises a tank for condensed water. 
     
     
         11 . A system for thermal or thermochemical treatment of metallic workpieces with subsequent water spray quenching, comprising
 one or more charge carriers for the storage of workpieces;   an oven for the thermal or thermochemical treatment of workpieces disposed on one or more charge carriers, wherein the oven is designed and set up to heat up the workpieces to a temperature of 750 to 1100° C.;   an apparatus for water spray quenching as claimed in  claim 1 ; and   an automated transfer apparatus designed and set up to transfer workpieces disposed on one or more charge carriers within a period of 10 to 60 s from the oven into a quench chamber of the apparatus.   
     
     
         12 . A method of water spray quenching of thermally or thermochemically treated metallic workpieces, comprising the steps of:
 disposing one or more thermochemically treated workpieces in a charge volume V 0  of an apparatus for water spray quenching;   atomizing water in air or nitrogen in order to produce a spray mist;   passing spray mist through the charge volume V 0 ; wherein   the charge volume V 0  is in a range of greater than or equal to 0.045 m 3  to less than or equal to 3.5 m 3 ;   the spray mist has a water content of 2.5% to 40% by volume;   the spray mist has a Sauter diameter of 20 to 2000 μm; and   a spray mist flow through the charge volume V 0  is 0.05 to 25 m 3 /s or the spray mist is recirculated in the charge volume V 0  at a spray mist volume flow rate of 0.05 to 25 m 3 /s.   
     
     
         13 . The method as claimed in  claim 12 , wherein the one or more workpieces are cooled down from a temperature of 750 to 1100° C. to a temperature of 20° C. to 250° C. 
     
     
         14 . The method as claimed in  claim 12 , wherein the at least one atomizer produces 0.05 to 25 m 3 /s of spray mist. 
     
     
         15 . The method as claimed in  claim 12 , wherein a spray mist throughput between an inlet and an outlet of the quench chamber is 0.05 to 25 m 3 /s.