Patent ID: 8388774
Filing Date: 2013-03-05
Classification: C21D

Abstract:
1. A multi-wave thermal process for treating a metal to improve at least one structural characteristic of the metal, the thermal process comprising: a. placing the metal with a metal temperature within a thermal control apparatus comprising a chamber with a chamber temperature; b. selecting a first target temperature based on the metal, wherein the first target temperature ranges from −120 degrees Fahrenheit to −380 degrees Fahrenheit; c. selecting a first temperature rate based on the metal, a size of the metal, a mass of the metal or combinations thereof, wherein the first temperature rate ranges from 0.25 degrees Fahrenheit per minute to 20 degrees Fahrenheit per minute; d. controlling the first temperature rate while cryogenically chilling the metal by introducing a first cryogenic material into the thermal control apparatus to decrease the metal temperature, while preventing over-stressing of the metal, to the first target temperature at the first temperature rate, and while cryogenically chilling the metal to the first target temperature, inserting at least one stabilizing hold time from 30 seconds to 90 minutes on the metal at an first intermediate temperature for equalization of the metal temperature uniformly throughout the metal, thereby creating uniformity in a microcrystalline structure of the metal, wherein the at least one stabilizing hold time corresponds to the size of the metal, the metal temperature, a thermal conductivity of the metal, or combinations thereof; e. stopping the introduction of the first cryogenic material into the chamber once the first target temperature is reached and holding the metal at the first target temperature for at least two hours; f. selecting a second target temperature for the metal, wherein the second target temperate ranges from 0 degrees Fahrenheit to 1400 degrees Fahrenheit; g. selecting a second temperature rate, wherein the second temperature rate ranges from 0.25 degrees Fahrenheit per minute to 20 degrees Fahrenheit per minute; h. controlling the second temperature rate while heating the metal to the second target temperature; i. increasing the metal temperature to the second target temperature at the second temperature rate and holding the metal at the second target temperature for at least fifteen minutes; j. selecting a third target temperature for the metal, wherein the third target temperature ranges from −120 degrees Fahrenheit to −380 degrees Fahrenheit; k. selecting a third temperature rate, wherein the third temperature rate ranges from 0.25 degrees Fahrenheit per minute to 20 degrees Fahrenheit per minute; l. controlling the third temperature rate while cryogenically chilling the metal by introducing a second cryogenic material into the thermal control apparatus to decrease the metal temperature, while preventing over-stressing of the metal, to the third target temperature at the third temperature rate, and while cryogenically chilling the metal to the third target temperature, inserting at least one equalizing hold time from 1 minute to 2 hours on the metal at a second intermediate temperature for equalization of the metal temperature uniformly throughout the metal, thereby creating uniformity in the microcrystalline structure of the metal, wherein the at least one equalizing hold time corresponds to the size of the metal, the metal temperature, the thermal conductivity of the metal, or combinations thereof; m. stopping the introduction of the second cryogenic material into the chamber once the third target temperature is reached and holding the metal at the third target temperature for at least two hours; n. selecting a fourth target temperature for the metal, wherein the fourth target temperature ranges from 0 degrees Fahrenheit to 1400 degrees Fahrenheit; o. selecting a fourth temperature rate, wherein the fourth temperature rate ranges from 0.25 degrees Fahrenheit per minute to 20 degrees Fahrenheit per minute; p. controlling the fourth temperature rate while increasing the chamber temperature to the fourth target temperature; and q. increasing the metal temperature to the fourth target temperature at the fourth temperature rate and holding the metal at the fourth target temperature for at least fifteen minutes, resulting in a treated metal without fractures and with an organized microcrystalline structure.