# US 5,704,998 A · Hot rolling high-strength steel structural members

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- Number: US 5,704,998 A
- Document ID: US5704998A
- Status: Granted
- Kind: A
- Application number: 08/532,534
- Filed: 1995-09-22
- Granted: 1998-01-06
- Earliest claimed: 1990-10-24
- Assignees: Consolidated Metal Products, Inc.
- Inventors: Hugh M. Gallagher, Jr.
- Web page: https://patentgrep.com/patent/US5704998A

## CPC

- B60G 21/0551: {Mounting means therefor}
- C21D 1/02: Hardening articles or materials formed by forging or rolling, with no further heating beyond that required for the formation
- C21D 7/13: by hot working
- C21D 8/00: Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02)
- C22C 38/04: containing manganese
- C22C 38/12: containing tungsten, tantalum, molybdenum, vanadium, or niobium
- B60G 2204/1222: Middle mounts of stabiliser on vehicle body or chassis
- B60G 2204/44: Centering or positioning means
- B60G 2204/45: Stops limiting travel
- B60G 2206/427: Stabiliser bars or tubes
- C21D 9/0068: {for particular articles not mentioned below}
- C21D 2211/008: Martensite
- Y10S 72/70: Deforming specified alloys or uncommon metal or bimetallic work
- B60G: VEHICLE SUSPENSION ARRANGEMENTS (air-cushion vehicles B60V; {cycle suspensions B62K25/00})
- C21D: MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B)
- C22C: ALLOYS (treatment of alloys C21D, C22F)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

High strength steel structural members and a method of making same are disclosed by providing high-strength steel material having a specific chemical composition and preferably a tensile strength of at least about 120,000 psi and a yield strength of at least about 90,000 psi and hot rolling the steel material to provide the structural member of desired geometric configuration.

## Claims

### Claim 1

A method of making a high-strength steel structural member comprising the steps of:
providing high-strength steel material having a tensile strength of at least about 120,000 psi and a yield strength of at least about 90,000 psi, wherein the high-strength steel material comprises, by weight percent:
carbon about 0.30 to about 0.65%
manganese about 0.30 to about 2.5%
at least 1 grain refiner from the group consisting of aluminum, niobium, titanium and vanadium, and mixtures thereof, in an effective amount for grain refining up to about 0.35% iron balance; and
hot rolling the high strength steel material to provide a structural member having a uniform cross-sectional configuration over at least a portion of its length, said uniform cross-sectional configuration being different than a configuration of said material and including at least one flange having a thickness less than an overall perimeter dimension of said cross-sectional configuration, said at least one flange providing increased load bearing capacity to said structural member.

### Claim 2 (depends on 1)

The method of claim 1 wherein said mechanical properties of tensile strength and yield strength of said structural member are produced without further processing steps to strengthen said structural member.

### Claim 3 (depends on 1)

The method of claim 1 wherein the high-strength steel material comprises, by weight percent:
carbon about 0.40 to about 0.55%
manganese about 0.30 to about 2.50%
at least 1 grain refiner from the group consisting of aluminum, niobium, titanium and vanadium, and mixtures thereof, in an effective amount for grain refining up to about 0.20% iron balance.

### Claim 4 (depends on 1)

The method of claim 1 wherein the high-strength steel material comprises, by weight percent:
carbon about 0.50 to about 0.55%
manganese about 1.20 to about 1.65%
at least 1 grain refiner from the group consisting of aluminum, niobium, titanium and vanadium, and mixtures thereof, in an effective amount for grain refining about 0.03 to about 0.20% iron balance.

### Claim 5 (depends on 1)

The method of claim 1 wherein said hot rolling is carried out at a temperature above about 2000.degree. F.

### Claim 6 (depends on 1)

The method of claim 1 wherein said uniform cross-sectional configuration is selected from the group consisting of O, L, C, Z, I, T, U, V, and W shapes.

### Claim 7 (depends on 1)

The method of claim 1 further comprising:
cooling said structural member at an accelerated and controlled cooling rate.

### Claim 8 (depends on 1)

The method of claim 1 wherein said grain refiner is vanadium.

### Claim 9

A method of making a high-strength steel structural member comprising the steps of:
providing high-strength steel material having at least partially a martensite microstructure and a tensile strength of at least about 120,000 psi and a yield strength of at least about 90,000 psi;
wherein the high-strength steel material comprises, by weight percent:
carbon about 0.30 to about 0.65%
manganese about 0.30 to about 2.5%
at least 1 grain refiner from the group consisting of aluminum, niobium, titanium and vanadium, and mixtures thereof, in an effective amount for grain refining up to about 0.35% iron balance; and
hot rolling the steel material to provide a structural member having a uniform cross-sectional configuration over at least a portion of its length, said uniform cross-sectional configuration including at least one flange having a thickness less than an overall perimeter dimension of said cross-sectional configuration, said at least one flange providing increased load bearing capacity to said structural member.

### Claim 10 (depends on 9)

The method of claim 9 wherein the high-strength steel material comprises, by weight percent:
carbon about 0.50 to about 0.55%
manganese about 1.20 to about 1.65%
at least 1 grain refiner from the group consisting of aluminum, niobium, titanium and vanadium, and mixtures thereof, in an effective amount for grain refining about 0.03 to about 0.20% iron balance.

### Claim 11 (depends on 9)

The method of claim 9 wherein said uniform cross-sectional configuration is selected from the group consisting of O, L, C, Z, I, T, U, V, and W shapes.

### Claim 12 (depends on 9)

The method of claim 9 further comprising:
cooling said structural member at an accelerated and controlled cooling rate.

### Claim 13 (depends on 9)

The method of claim 9 wherein said grain refiner is vanadium.

### Claim 14

A method of making a high-strength steel structural member comprising the steps of:
providing high-strength steel material having a tensile strength of at least about 120,000 psi and a yield strength of at least about 90,000 psi, said high-strength steel material comprising, by weight percent:
carbon about 0.50 to about 0.55%
manganese about 1.20 to about 1.65%
at least 1 grain refiner from the group consisting of aluminum, niobium, titanium and vanadium, and mixtures thereof, in an effective amount for grain refining about 0.03 to about 0.20% iron balance;
hot rolling the steel material at a temperature above about 2000.degree. F., to provide a structural member having a uniform cross-sectional configuration over at least a portion of its length, said uniform cross-sectional configuration including at least one flange having a thickness less than an overall perimeter dimension of said cross-sectional configuration, said at least one flange providing increased load bearing capacity to said structural member, said uniform cross-sectional configuration being selected from the group consisting of O, L, C, Z, I, T, U, V, and W shapes; and
cooling said structural member.