US4088511A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Steels combining toughness and machinability
Assignee: Lasalle Steel Co
•
Filing: 1976-07-29
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Granted: 1978-05-09
•
Expires: 1996-07-29
Abstract
Abstract A method for strengthening of carbon and low alloy steels and steels produced thereby wherein a carbon or low alloy steel is partially austenitized to produce a ferrite-austenite mixture, the resulting ferrite-austenite mixture is quenched to an intermediate temperature to render the austenite metastable, with the quenching being at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and working the quenched steel at a temperature up to the maximum temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.
Inventors
- 👤 Michael J. Rowney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:32
CPC Classifications
C; C21; C21D; C21D8/00
Claims Analysis
Total Claims: 58
Claim 1
Independent Claim
98 words
A method for the strengthening of carbon and low alloy steels comprising (1) partially austenitizing a carbon or low alloy steel to produce a ferrite-austenite mixture, (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.
Claim 2
Independent Claim
98 words
A method for the strengthening of carbon and low alloy steels comprising (1) partially austenitizing a carbon or low alloy steel to produce a ferrite-austenite mixture, (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.
Claim 3
Dependent Claim
17 words
A method as defined in claim 1 wherein the steel contains at least 10% by volume ferrite.
Claim 4
Dependent Claim
15 words
A method as defined in claim 1 wherein the steel is a hypoeutectoid carbon steel.
Claim 5
Dependent Claim
20 words
A method as defined in claim 1 wherein the steel is a carbon steel containing from 0.1 to 0.7% carbon.
Claim 6
Dependent Claim
24 words
A method as defined in claim 1 wherein the steel is a low alloy steel containing less than 5% total alloying elements by weight.
Claim 7
Dependent Claim
20 words
A method as defined in claim 1 wherein the steel partially austenitized is a steel formed of ferrite and pearlite.
Claim 8
Dependent Claim
16 words
A method as defined in claim 1 wherein the steel is an AISI/SAE Grade 1144 steel.
Claim 9
Dependent Claim
23 words
A method as defined in claim 1 wherein the steel is partially austenitized at a temperature ranging from about 1340° to 1680° F.
Claim 10
Dependent Claim
24 words
A method as defined in claim 1 wherein the steel is partially austenitized by rapid heating by passing an electric current through the steel.
Claim 11
Dependent Claim
20 words
A method as defined in claim 1 wherein the steel is partially austenitized by heating in less than 10 minutes.
Claim 12
Dependent Claim
49 words
A method as defined in claim 9 wherein the electric current is passed through the steel to heat the steel until the increase in temperature of the steel ceases, and then the amount of current passed through the steel is adjusted to maintain the steel at a constant temperature.
Claim 13
Dependent Claim
58 words
A method as defined in claim 9 wherein the electric current is passed through the steel until the increase in temperature of the steel ceases, and then the flow of electric current is stopped after a pre-determined temperature is reached and a pre-determined time has passed from the time when the increase in temperature of the steel ceased.
Claim 14
Dependent Claim
13 words
A carbon or low alloy steel produced by the method of claim 1.
Claim 15
Dependent Claim
21 words
A steel as defined in claim 13 wherein the steel is a carbon steel containing carbon up to 0.7% by weight.
Claim 16
Dependent Claim
23 words
A steel as defined in claim 13 wherein the steel is a low alloy steel containing less than 5% by weight alloying elements.
Claim 17
Dependent Claim
25 words
A steel as defined in claim 15 wherein the alloying element is selected from the group consisting of chromium, molybdenum, nickel, manganese and combinations thereof.
Claim 18
Independent Claim
110 words
A method for the strengthening of carbon and low alloy steels comprising: (1) partially austenitizing a hypoeutectoid carbon steel or low alloy steel by rapid heating to produce a ferrite-austenite mixture, (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist, and (4) cooling the steel whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture, with such conversion being accelerated and extended during working and/or cooling.
Claim 19
Independent Claim
110 words
A method for the strengthening of carbon and low alloy steels comprising: (1) partially austenitizing a hypoeutectoid carbon steel or low alloy steel by rapid heating to produce a ferrite-austenite mixture, (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist, and (4) cooling the steel whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture, with such conversion being accelerated and extended during working and/or cooling.
Claim 20
Dependent Claim
17 words
A method as defined in claim 17 wherein the steel contains at least 10% by volume ferrite.
Claim 21
Dependent Claim
20 words
A method as defined in claim 17 wherein the steel is a carbon steel containing from 0.1 to 0.7% carbon.
Claim 22
Dependent Claim
24 words
A method as defined in claim 17 wherein the steel is a low alloy steel containing less than 5% total alloying elements by weight.
Claim 23
Dependent Claim
20 words
A method as defined in claim 17 wherein the steel partially austenitized is a steel formed of ferrite and pearlite.
Claim 24
Dependent Claim
16 words
A method as defined in claim 17 wherein the steel is an AISI/SAE Grade 1144 steel.
Claim 25
Dependent Claim
24 words
A method as defined in claim 17 wherein the steel is partially austenitized by rapid heating by passing an electric current through the steel.
Claim 26
Dependent Claim
49 words
A method as defined in claim 23 wherein the electric current is passed through the steel to heat the steel until the increase in temperature of the steel ceases, and then the amount of current passed through the steel is adjusted to maintain the steel at a constant temperature.
Claim 27
Dependent Claim
58 words
A method as defined in claim 23 wherein the electric current is passed through the steel until the increase in temperature of the steel ceases, and then the flow of electric current is stopped after a pre-determined temperature is reached and a pre-determined time has passed from the time when the increase in temperature of the steel ceased.
Claim 28
Dependent Claim
19 words
A method as defined in claim 17 wherein the steel is subjected to working by advancing through a die.
Claim 29
Dependent Claim
20 words
A method as defined in claim 17 wherein the steel is subjected to working at a temperature above ambient temperature.
Claim 30
Dependent Claim
23 words
A method as defined in claim 17 wherein the steel is subjected to working at a temperature ranging from 600° to 1100° F.
Claim 31
Dependent Claim
16 words
A method as defined in claim 17 which includes the step of strain relieving the steel.
Claim 32
Dependent Claim
15 words
A method as defined in claim 17 which includes the step of straightening the steel.
Claim 33
Independent Claim
107 words
A method for the strengthening of carbon and low alloy steels comprising: (1) partially austenitizing a hypoeutectoid carbon or low alloy steel by rapid heating in less than ten minutes to produce a ferrite-austenite mixture. (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.
Claim 34
Independent Claim
107 words
A method for the strengthening of carbon and low alloy steels comprising: (1) partially austenitizing a hypoeutectoid carbon or low alloy steel by rapid heating in less than ten minutes to produce a ferrite-austenite mixture. (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.
Claim 35
Dependent Claim
25 words
A method as defined in claim 31 wherein the steel is cooled to ambient temperature after quenching, and is subjected to working at ambient temperature.
Claim 36
Dependent Claim
38 words
A method as defined in claim 31 wherein the steel is cooled to room temperature after quenching, reheated to an elevated temperature above ambient temperature but below the critical temperature and subjected to working at said elevated temperature.
Claim 37
Dependent Claim
55 words
A method as defined in claim 31 wherein the steel is held after quenching for a time sufficient to enable the temperature of the steel to equalize over the cross section thereof, cooled to a temperature below the equalization temperature and subjected to working at a temperature above ambient temperature but below the equalization temperature.
Claim 38
Dependent Claim
17 words
A method as defined in claim 34 wherein the equalization temperature ranges from 600° to 1100° F.
Claim 39
Dependent Claim
51 words
A method as defined in claim 31 wherein the steel is held after quenching for a time sufficient for the temperature of the steel to equalize over the cross section thereof, heated to a temperature above the equalization temperature and subjected to working while at a temperature above the equalization temperature.
Claim 40
Dependent Claim
17 words
A method as defined in claim 36 wherein the equalization temperature ranges from 600° to 1100° F.
Claim 41
Dependent Claim
17 words
A method as defined in claim 31 wherein the steel contains at least 10% by volume ferrite.
Claim 42
Dependent Claim
16 words
A method as defined in claim 31 wherein the steel is an AISI/SAE Grade 1144 steel.
Claim 43
Dependent Claim
23 words
A method as defined in claim 31 wherein the steel is partially austenitized at a temperature ranging from about 1340° to 1680° F.
Claim 44
Dependent Claim
10 words
A steel produced by the method defined in claim 31.
Claim 45
Dependent Claim
10 words
A steel produced by the method defined in claim 17.
Claim 46
Independent Claim
117 words
A method for the strengthening of carbon and low alloy steels comprising: (1) partially austenitizing a hypoeutectoid carbon or low alloy steel by passing an electric current through the steel to rapidly heat the steel in less than ten minutes and produce a ferrite-austenite mixture, (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.
Claim 47
Independent Claim
117 words
A method for the strengthening of carbon and low alloy steels comprising: (1) partially austenitizing a hypoeutectoid carbon or low alloy steel by passing an electric current through the steel to rapidly heat the steel in less than ten minutes and produce a ferrite-austenite mixture, (2) quenching the partially austenitized steel to an intermediate temperature above the M s temperature for the steel at a rate sufficient to avoid transformation of the austenite to ferrite and pearlite, and (3) working the quenched steel at a temperature ranging from ambient temperature up to a temperature at which bainite can exist whereby the ferrite-austenite mixture is converted to a ferrite-bainite mixture having high levels of machinability, strength and toughness.
Claim 48
Dependent Claim
25 words
A method as defined in claim 43 wherein the steel is cooled to ambient temperature after quenching, and is subjected to working at ambient temperature.
Claim 49
Dependent Claim
38 words
A method as defined in claim 43 wherein the steel is cooled to room temperature after quenching, reheated to an elevated temperature above ambient temperature but below the critical temperature and subjected to working at said elevated temperature.
Claim 50
Dependent Claim
55 words
A method as defined in claim 43 wherein the steel is held after quenching for a time sufficient to enable the temperature of the steel to equalize over the cross section thereof, cooled to a temperature below the equalization temperature and subjected to working at a temperature above ambient temperature but below the equalization temperature.
Claim 51
Dependent Claim
17 words
A method as defined in claim 46 wherein the equalization temperature ranges from 600° to 1100° F.
Claim 52
Dependent Claim
51 words
A method as defined in claim 43 wherein the steel is held after quenching for a time sufficient for the temperature of the steel to equalize over the cross section thereof, heated to a temperature above the equalization temperature and subjected to working while at a temperature above the equalization temperature.
Claim 53
Dependent Claim
17 words
A method as defined in claim 43 wherein the steel contains at least 10% by volume ferrite.
Claim 54
Dependent Claim
24 words
A method as defined in claim 43 wherein the steel is a low alloy steel containing less than 5% total alloying elements by weight.
Claim 55
Dependent Claim
16 words
A method as defined in claim 43 wherein the steel is an AISI/SAE Grade 1144 steel.
Claim 56
Dependent Claim
49 words
A method as defined in claim 43 wherein the electric current is passed through the steel to heat the steel until the increase in temperature of the steel ceases, and then the amount of current passed through the steel is adjusted to maintain the steel at a constant temperature.
Claim 57
Dependent Claim
58 words
A method as defined in claim 43 wherein the electric current is passed through the steel until the increase in temperature of the steel ceases, and then the flow of electric current is stopped after a pre-determined temperature is reached and a pre-determined time has passed from the time when the increase in temperature of the steel ceased.
Claim 58
Dependent Claim
10 words
A steel produced by the method defined in claim 43.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1981-05-08 | 1981-11-07 | 1982-05-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-05-08 | 1985-11-07 | 1986-05-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-05-08 | 1989-11-07 | 1990-05-09 | $7700.00 | Window Closed / Lapsed |