Method of heat treating metal with liquid coolant containing dissolved gas
AssigneeAluminum Company of America
InventorsHo Yu, Jeffrey A. Nicol, Robert A. Ramser, Daniel E. Hunter
Life of this patent
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Abstract
A method of quenching a metal object comprising: (a) providing a reservoir of liquid coolant containing gas that has been dissolved therein; and (b) immersing the metal object in the reservoir to quench the metal. The gas is selected from the group consisting of nitrogen and carbon dioxide and is preferably carbon dioxide. The gas is preferably maintained within the range of 0.001 to 0.2 standard cubic feet of gas per gallon of coolant. The liquid coolant is preferably water. In a preferred embodiment, the reservoir of liquid coolant is open to ambient pressure and temperature.
Claims55
A method of quenching a wrought metal object selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising:
- (a) providing a liquid reservoir of coolant which is open to ambient pressure, said liquid having a temperature from about 100.degree. F. to about 180.degree. F. and consisting essentially of water and sufficient quantity of deliberately dissolved carbon dioxide to retard cooling as compared to water of the same temperature without said deliberately dissolved carbon dioxide, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- and
- (b) immersing a heated wrought metal object in said liquid reservoir to quench said metal object.
A method of heat treating at least one wrought metal object selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising:
- (a) heating at least one wrought metal object to a solution heat temperature of about 800.degree. F. to about 1100.degree. F.;
- and
- (b) immersing said heated object in a reservoir of liquid coolant, said liquid coolant having a temperature from about 100.degree. F. to about 180.degree. F. and consisting essentially of water and sufficient quantity of deliberately dissolved carbon dioxide, to retard cooling as compared to water of the same temperature without said deliberately dissolved carbon dioxide, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures, said reservoir having a blanket of carbon dioxide thereover.
A method of quenching a solid metal object selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising:
- heating a solid metal object to a temperature of 800.degree. F. to 1100.degree. F.;
- and
- submerging said solid metal object into a reservoir of carbonated water which is open to the atmosphere, said carbonated water having a temperature from about 100.degree. F. to about 180.degree. F. and consisting essentially of water and sufficient quantity of carbon dioxide dissolved therein to retard the initial cooling of said solid metal object as compared to water of the same temperature without deliberately dissolved carbon dioxide, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures.
A method of quenching a solid aluminum metal piece in a reservoir of carbonated water consisting essentially of water having a temperature from about 100.degree. F. to about 180.degree. F. and sufficient quantity of deliberately dissolved carbon dioxide as compared to water of the same temperature, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures.
A method of quenching a heated solid object formed from an aluminum alloy containing at least 75 percent or more by weight of aluminum, said method comprising:
- (a) providing a reservoir of water having a temperature from about 100.degree. F. to about 180.degree. F. and which is open to ambient pressure, said reservoir consisting essentially of water and deliberately dissolved carbon dioxide in which gaseous carbon dioxide has been intentionally dissolved in said water in sufficient quantity to retard cooling of the heated object from a temperature above 600.degree. F. as compared to water of the same temperature, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- and
- (b) submerging said solid heated object in said reservoir to quench said material.
A method of quenching a solid object selected from the group consisting of aluminum, iron, magnesium and alloys thereof with a liquid consisting essentially of water having a temperature from about 100.degree. F. to about 180.degree. F. and dissolved carbon dioxide which has been intentionally introduced into said water to retard cooling as compared to water of the same temperature, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures, wherein sad liquid is open to atmospheric pressure and the object is heat treated, said method comprising the steps of:
- (a) detecting the amount of carbon dioxide dissolved in the liquid;
- (b) comparing said amount of carbon dioxide dissolved in said liquid to a reference range;
- (c) controlling the amount of carbon dioxide that is being dissolved in said liquid so that the amount of carbon dioxide in said liquid is maintained within said reference range;
- and
- (d) immersing said solid object in said liquid to quench said object.
A method of solution heat treating solid metal objects selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising the steps of:
- (a) heating solid metal objects to a solution heat treatment temperature;
- (b) providing water;
- (c) dissolving carbon dioxide in said water under pressure and then releasing said pressure to form a liquid coolant consisting essentially of water having a temperature from about 100.degree. F. to about 180.degree. F. and carbon dioxide dissolved therein, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- (d) generating a signal which is related to the amount of carbon dioxide dissolved in said liquid coolant;
- (e) comparing said amount of carbon dioxide dissolved in said liquid coolant to a reference range;
- (f) controlling the amount of carbon dioxide that is being dissolved in said liquid coolant so that the amount of carbon dioxide in said solution is within said reference range;
- and
- (g) immersing said solid heated metal objects in said liquid coolant to quench said metal objects.
An improved method of solution heat treating a solid metal object selected from the group consisting of aluminum, iron, magnesium and alloys thereof in a liquid, the improvement comprising the steps of:
- (a) providing a liquid consisting essentially of water having a temperature from about 100.degree. F. to about 180.degree. F. and deliberately dissolved carbon dioxide which has been deliberately introduced into said liquid, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures, said liquid being open to ambient pressure;
- (b) generating a signal which is related to the amount of carbon dioxide dissolved in a liquid;
- (c) comparing said generated signal to a reference range;
- (d) controlling the amount of carbon dioxide that is dissolved in said liquid so that the amount of carbon dioxide in said solution is within said reference range;
- and
- (e) immersing said heated solid metal object in said liquid to quench said metal object.
A method of quenching a solid metal part fabricated from an alloy containing at least about 75 wt. % aluminum, said method comprising:
- (a) providing water reservoir open to ambient pressure having a temperature from about 100.degree. F. to about 180.degree. F. and consisting essentially of water and deliberately dissolved carbon dioxide gas which has been intentionally dissolved therein, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- (b) periodically generating a signal which is related to the amount of carbon dioxide that is dissolved in said water reservoir, said signal generated using an infrared spectrometer;
- (c) comparing said generated signal to a reference range;
- (d) controlling the amount of carbon dioxide that is dissolved into said water reservoir so that the amount of gas in said solution is within said reference range;
- and
- (e) quenching said metal part in said water reservoir.
A method of quenching a solid metal article selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising immersing said metal article in a coolant that cools said article during a first time period at a rate of cooling approximating the cooling rate of warm water and during a second period of time at a second rate of cooling which is faster than that of warm water, said method comprising providing a reservoir of water having a temperature from about 100.degree. F. to about 180.degree. F. and;
- and deliberately dissolving gas in said reservoir, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures.
A method of quenching a solid metal object selected from the group consisting essentially of aluminum, iron, magnesium and alloys thereof comprising:
- (a) providing an open reservoir consisting essentially of water having a temperature from about 100.degree. F. to about 180.degree. F. and carbon dioxide which has been intentionally dissolved therein, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- and
- (b) immersing a solid metal object in said reservoir to quench metal.
A method of quenching wrought metal objects selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising:
- (a) placing water under pressure:
- (b) injecting pressurized carbon dioxide gas into said pressurized water to form a pressurized mixture of water and carbon dioxide gas;
- (c) mixing said mixture of water and carbon dioxide gas to dissolve said gas in said water;
- (d) forming a bath having a temperature from about 100.degree. F. to about 180.degree. F. from said mixture of water and carbon dioxide deliberately dissolved therein, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures, said bath being open to ambient atmospheric conditions to permit some gas to escape from said bath and having a blanket of gaseous carbon dioxide over said bath to retard said escape;
- and
- (e) immersing heated wrought metal objects one or more at a time in said liquid bath to quench said wrought metal objects.
A method of quenching a wrought metal object selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising:
- (a) providing a bath of water which is open to ambient atmospheric conditions,
- (b) removing a portion of said bath and injecting pressurized carbon dioxide gas into said portion under pressure to form a pressurized mixture of water and carbon dioxide gas;
- (c) mixing said pressurized mixture and thereby form an aqueous solution consisting essentially of water having a temperature from about 100.degree. F. to about 180.degree. F. and deliberately dissolved carbon dioxide gas, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- (d) introducing said aqueous solution into said bath;
- (e) performing (b)-(d) to maintain the level of dissolved carbon dioxide gas at a predetermined value;
- and
- (f) immersing heated wrought metal object in said bath one or more at a time to quench said wrought metal object.
A method of quenching a wrought metal object selected from the group consisting of aluminum, iron, magnesium and alloys thereof in an aqueous solution, said method comprising:
- (a) providing a bath which is open to ambient pressure consisting essentially of water having a temperature from about 100.degree. F. to about 180.degree. F. and CO.sub.2 which has been intentionally dissolved into said liquid, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- and
- (b) immersing a heated wrought metal object in said bath to quench said metal object, during said immersion the cooling rate of said metal object is influenced as follows:
- (i) said bath forming a water vapor and CO.sub.2 gas layer on surfaces of said metal object in response to said bath contacting the hot surface of said metal object while it is above critical temperature, said vapor and gas layer partially insulating said metal from said bath and thereby retarding said cooling rate, said vapor and gas layer continually being replaced by a new layer that continues to be formed so long as the metal object is above a critical temperature;
- and
- (ii) as said metal object cools, the rate of new water vapor and gas generation decreases and said vapor and gas insulation layer gradually deteriorates so said bath makes direct contact with said surface of said metal object when its temperature falls below said critical temperature so that the cooling rate approximates that of a water bath that does not contain intentionally dissolved CO.sub.2 gas when said object is below said critical temperature.
A method of quenching wrought metal objects selected from the group consisting of aluminum, iron, magnesium and alloys thereof comprising:
- providing a large open bath of water at atmospheric pressure having a temperature in a range from about 100.degree. F. to about 180.degree. F. and containing carbon dioxide which has been dissolved in the water by mixing pressurized carbon dioxide into a portion of said bath which is fed from the bath through a pressurized mixer and returned to the bath;
- controlling said mixing to maintain essentially single phase bath of water and dissolved CO.sub.2 in sufficient quantity to retard cooling of said metal objects during the initial portion of quenching, the amount of said dissolved carbon dioxide being present from about 0.01 to about 0.10 standard cubic feet of gas per gallon of water, the dissolved carbon dioxide being higher for lower water temperatures and lower for higher water temperatures;
- and
- immersing heated wrought metal objects one or more at a time in said bath to quench them.
Dependencies are inferred from the claim text.