Method of soft annealing high carbon steel
AssigneeOvako Steel AB
InventorsThore Lund, Staffan Larsson, Patrik Ölund
Life of this patent
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Abstract
A method for soft annealing of high carbon steel, characterized by taking objects to be soft annealed directly from a hot forming step and cooling to below Al−20° C.; heating the objects to Al+20° C. or above, and then cooling the objects down to beneath the Al temperature of the steel quickly as in air, which step is performed at least once; heating the objects to Al+20° C. or above, cooling the objects down to about 740° C., and then cooling the objects down to about 690° C. at a cooling rate of 3.5° C./min. or lower; and finally cooling the objects down to ambient temperature.
Claims6
A method for soft annealing high carbon steel articles comprising:
- hot forming an article of high carbon steel;
- cooling the hot formed article to a temperature at least 20° C. below the temperature;
- heating the cooled article to a temperature at least 20 C. above the Al temperature;
- quickly cooling the heated article below the Al temperature;
- heating the cooled article to a temperature at least 20° C. above the Al temperature;
- cooling the heated article to about 740° C. at a first cooling rate;
- then cooling the said article down from about 740° C. to about 690 ° C. at a second cooling rate of a maximum of 3.5° C./min;
- and
- cooling to ambient temperature.
Dependencies are inferred from the claim text.