AW: DET divorced eutectoid transformation
hatte mich in der letzten Zeit auch noch theoretisch mit dem DET Process beschäftigt
da gibts eine entsprechende amerikanische Patentanmeldung
um einen ultrahochkarbonierten Stahl von 1,0%-2,1% in seiner Matrix in mehr Austenit zu verformen. Dabei wird der Stahl auf etwas höher als Acm erhitzt um ihn dann bis A1 abzukühlen und dabei zu bearbeiten: auf Englisch liest sich das so:
DET - von Jeff Pringle in lesbare Form gebracht
Divorced eutectoid transformation process and product of ultrahigh carbon steels
1. A method for processing steel employing a divorced eutectoid transformation comprising the steps of:
(a) heating steel to a temperature in excess of the upper critical temperature, to form an austenite matrix in which substantially all of the carbides are dissolved;
(B cooling the steel from the upper critical temperture to about the lower critical temperature, and forging the steel during at least part of the cooling step;
c) cooling the steel to below the lower critical temperature to form pearlite and ferrite;
(d) reheating the steel to a soaking temperature approximately 50° C. above the lower critical temperature;
(e) soaking the steel in the soaking temperature range for a sufficient time such that the major portion of the pearlite is dissolved into the austenite matrix; and
(f) cooling at a rate equivalent to air cooling a second time to below the lower critical temperature.
2. the steel treated in step (e) is forged during step (f) before the steel is cooled to the lower critical temperature.
3. the steel treated in step (e) is forged during step (f) both above, at and below the lower critical temperature.
4. A method for processing steel comprising the steps of:
(a) heating previously normalized steel with a carbon content from about 1.0% to 2.1%, to a soaking temperature approximately 50° C. above lower critical;
(B maintaining the steel treated in step (a) at a soaking temperature for a time sufficient such that the carbides are dissolved into the austenite; and
c)5. the steel treated in step (B is forged during step c) before the steel is cooled to the lower critical temperature.
6. the steel treated in step (B is forged during the step c) both above and below the lower critical temperature.
7. A method for processing steel comprising the steps of:
(a) heating previously hardened steel with a carbon content from about 1.0% to 2.1%, to approximately 50° C. above the lower critical temperature
B) maintaining the steel at a soaking temperature for a time sufficient such that the eutectoid carbides are dissolved into the austenite; and
c) cooling at a rate equivalent to air cooling the steel of step (B to below lower critical temperature.
8. The method of claim 7 in which the steel treated in step (B is forged during step © before the steel is cooled to the lower critical temperature.
9. The method of claim 7 in which the steel treated in step (B is forged during step © both above and below the lower critical temperature.
auch nachzulesen in:
http://forums.dfoggknives.com/index.php?showtopic=17975&st=20 post #28
im Grunde nix anderes als das, was alle Schmiede beim Ausschmieden von Tiegelstahl eh machen, wenn sie eine gute Temperaturkontrolle anwenden.
die bietet sich eh an, auch um die Glühfarben richtig wahrzunehmen und einschäzen zu können.
Das vorletzte Mal hatte ich deswegen ein Pyrometer dabei um die Temps möglichsts genau einzuhalten auch um das Schmiedeteil nicht zu kalt werden zu lassen,
da auch dann die Gefahr von neuen kleinen Rissen aufkommt...
lässt sich gut nachvollziehen, wenn man es mit diesen Infos hier verbindet:
http://www.haw-hamburg.de/fileadmin/user_upload/IWS/PDF/Skript_teil10.pdf
oder mit dem Eisen-Kohlenstoff Zustandsbild hier:
http://www.haw-hamburg.de/fileadmin/user_upload/IWS/PDF/Skript_teil09.pdf
