US3117037A - Production of high strength steel structural shapes - Google Patents

Production of high strength steel structural shapes Download PDF

Info

Publication number
US3117037A
US3117037A US139871A US13987161A US3117037A US 3117037 A US3117037 A US 3117037A US 139871 A US139871 A US 139871A US 13987161 A US13987161 A US 13987161A US 3117037 A US3117037 A US 3117037A
Authority
US
United States
Prior art keywords
sections
hot
steel
high strength
temperature
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US139871A
Inventor
John M Hodge
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
United States Steel Corp
Original Assignee
United States Steel Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by United States Steel Corp filed Critical United States Steel Corp
Priority to US139871A priority Critical patent/US3117037A/en
Application granted granted Critical
Publication of US3117037A publication Critical patent/US3117037A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/26—Methods of annealing
    • C21D1/30—Stress-relieving
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/008—Martensite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • 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
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

Definitions

  • This invention relates to the production of structural steel shapes formed of high strength steel and more particularly to a method of forming straight, high strength, steel structural shapes.
  • structural shapes are "ice rolled from such steels by conventional practice and while at hot-rolling temperatures and in an austenitic condition are straightened, preferably by roller straightening, directly folowing the hot-rolling. After straightening while in an austenitic condition the shapes are placed on conventional hot-beds and cooled to room temperature.
  • the steel transforms to a structure of lower bainite and martensite and because of the slow cooling rate is essentially straight due to lack of distortion during cooling and transformation. Any slight distortions at this stage can easily be removed by gagpress or the like straightening.
  • the cooling rate is sufficiently fast to produce a structure of lower bainite and martensite.
  • the sections Following transformation on the hotbed, the sections have the desired high strength but due to the presence of martensite may be lacking in toughness so that I prefer a final tempering step.
  • a method of producing high strength steel structural sections such as beams, channels and angles comprising hot-rolling sections of low-carbon steel having sufliciently high hardenability that it will harden during air cooling on a hot-bed, straightening said sections after hot-rolling and prior to cooling below the temperature at which the steel is austenitic, air cooling said sections to room temperature on a hot-bed at a rate sufficiently slow that distortion due to abrupt transformation does not occur but at a rate sufliciently fast to produce a martensitic-bainitic structure therein and thereafter tempering said sections at a temperature below the lower critical temperature thereof.
  • a method of producing high strength steel structural sections such as beams, channels and angles comprising forming sections of steel of the following composition:
  • a method of producing high strength steel structural sections such as beams, channels and angles comprising forming sections of steel of the following composition:
  • roller straightening said sections after hot-rolling and before cooling below an austenitizing temperature air cooling the straightened sections on a hot-bed at a cooling rate sufiiciently slow to prevent distortion therein but at a rate suificiently fast to produce a transformation of the structure of the steel to lower bainite and martensite and thereafter tempering the sections at a temperature below the critical temperature thereof.
  • a method of producing high strength steel structural sections such as beams, channels and angles comprising forming sections of steel of the following composition:
  • roller straightening said sections after hot-rolling and before cooling below an austenitizing temperature air cooling the straightened sections on a hot-bed at a cooling rate sufliciently slow to prevent distortion therein but at a rate sufficiently fast to produce a transformation of the structure of the steel to lower bainite and martensite and thereafter tempering the sections at a temperature below the critical temperature thereof.
  • a method of producing high-strength structural shapes such as beams, channels and angles comprising hot-rolling structural shapes from steel containing Percent Carbon About .15 Manganese About .26 Silicon About .21 Nickel About 2.95 Chromium About 1.83. Molybdenum About .48
  • hot-roller straightening said sections at the finish of the hot-rolling and before the sections have cooled below an austenitizing temperature, air cooling said sections on a hot-bed to produce straight sections having a lower bainite, martensitic structure therein and then tempering said sections at a temperature of about 1225 F.

Description

United States Patent 3,117 ,037 PRODUCTION OF HIGH STRENGTH STEEL STRUCTURAL SHAPES John M. Hodge, Pleasant Hills, Pa., assignor to United States Steel Corporation, a corporation of New Jersey No Drawing. Filed Sept. 22, 1961, Ser. No. 139,871 5 Claims. (Cl. 14812.3)
This invention relates to the production of structural steel shapes formed of high strength steel and more particularly to a method of forming straight, high strength, steel structural shapes.
In many structures such as bridges, towers, transportation and storage equipment there is a need for structural shapes having high strength. If structural shapes, such as beams, channels and angles having yield strengths in excess of 80,000 p.s.i. were available, a considerable reduction in weight could be obtained in such structures and along therewith reduced costs. Heretofore many attempts have been made to produce high strength in such structural shapes by resorting to conventional quenching and tempering. That is to say the high strengths were produced by drastically quenching the shapes formed of hardenable steel from an austenitizing temperature. While desired mechanical properties can be so obtained, the abrupt transformation or change in microstructure produces distortion so that the shapes have excessive camber, sweep, or twist or other distortion defects. Due to the high strength of such shapes, straightening by conventional straightening methods is very uneconomical and diflicult and moreover has a deleterious effect on the mechanical properties of the steel.
It is accordingly an object of the present invention to produce undistorted and straight structural shapes of high strength steel.
It is a further object to produce such shapes in an efiicient and economical manner.
I have discovered a method of producing structural shapes having strengths and properties comparable to quenched and tempered shapes and which are within commercial straightness tolerances. Successful utilization of the method of my invention requires the use of a low-carbon steel having a sufiiciently high hardenability that it will obtain the desired hardness air cooling on a conventional hot-bed. Steel within the following compositional limits is satisfactory for practicing my invention:
Percent Carbon .15/ .20 Manganese .20/ .50 Silicon .15/ .35 Nickel 250/425 Chromium 1.30/2.00 Molybdenum .35/ .55
with the balance iron, residual impurities and other elements in amounts which do not deleteriously affect the properties.
Within such ranges, I have two preferred compositions as follows:
Table 1 Carbon .15/.20 Manganese flicon. Nickel. Chrorni M olybdenum balance iron and residual impurities.
In accordance with my invention, structural shapes are "ice rolled from such steels by conventional practice and while at hot-rolling temperatures and in an austenitic condition are straightened, preferably by roller straightening, directly folowing the hot-rolling. After straightening while in an austenitic condition the shapes are placed on conventional hot-beds and cooled to room temperature. During cooling, the steel transforms to a structure of lower bainite and martensite and because of the slow cooling rate is essentially straight due to lack of distortion during cooling and transformation. Any slight distortions at this stage can easily be removed by gagpress or the like straightening. However, the cooling rate is sufficiently fast to produce a structure of lower bainite and martensite. Following transformation on the hotbed, the sections have the desired high strength but due to the presence of martensite may be lacking in toughness so that I prefer a final tempering step.
As an example of my invention, I have produced structural sections of steel of the following composition:
Percent Carbon .15 Manganese .26 Silicon .25 Nickel 2.95 Chromium 1.83 Molybdenum .48
After hot-rolling, the sections Were roller-straightened, cooled on a hot-bed to room temperature and thereafter tempered at 1225 F. The sections were straight within commercial tolerances. Mechanical properties of three different sections so produced were as follows:
As can be seen, these properties are equivalent to those obtained by quenching and tempering, including high strength and toughness. Moreover, the sections were straight Within commercial tolerances as produced.
While I have shown and described several specific embodiments of my invention, it will be understood that these embodiments are merely for the purpose of illustration and description and that various other forms may be devised within the scope of my invention, as defined in the appended claims.
I claim:
1. A method of producing high strength steel structural sections such as beams, channels and angles comprising hot-rolling sections of low-carbon steel having sufliciently high hardenability that it will harden during air cooling on a hot-bed, straightening said sections after hot-rolling and prior to cooling below the temperature at which the steel is austenitic, air cooling said sections to room temperature on a hot-bed at a rate sufficiently slow that distortion due to abrupt transformation does not occur but at a rate sufliciently fast to produce a martensitic-bainitic structure therein and thereafter tempering said sections at a temperature below the lower critical temperature thereof.
2. A method of producing high strength steel structural sections such as beams, channels and angles comprising forming sections of steel of the following composition:
Percent Carbon .15/ .20 Manganese .20/ .50 Silicon .15/ .35
Nickel 2.50/425 Chromium 130/200 Molybdenum .35/ .55
with the balance iron, residual impurities and other elements in amounts which do not deleteriously affect the properties, straightening said sections after hot-rolling and before cooling below an austenitizing temperature, air cooling the straightened sections at a cooling rate sufficiently slow to prevent distortion therein but at a rate sufficiently fast to produce a transformation of the structure of the steel to lower bainite and martensite and thereafter tempering the sections at a temperature below the critical temperature thereof.
3. A method of producing high strength steel structural sections such as beams, channels and angles comprising forming sections of steel of the following composition:
Percent Carbon .15/ .20
Manganese .20/ .45 Silicon .15/ .30
Nickel 2.75/3.25
Chromium 1.60/ 1.90
Molybdenum .40/ .60
balance iron and residual impurities, roller straightening said sections after hot-rolling and before cooling below an austenitizing temperature, air cooling the straightened sections on a hot-bed at a cooling rate sufiiciently slow to prevent distortion therein but at a rate suificiently fast to produce a transformation of the structure of the steel to lower bainite and martensite and thereafter tempering the sections at a temperature below the critical temperature thereof.
4. A method of producing high strength steel structural sections such as beams, channels and angles comprising forming sections of steel of the following composition:
Percent Carbon .15/ .20 Manganese .20/ .45 Silicon .15/ .30 Nickel 3.75/4.25 Chromium 1.75/2.00 Molybdenum .40/ .65
balance iron and residual impurities, roller straightening said sections after hot-rolling and before cooling below an austenitizing temperature, air cooling the straightened sections on a hot-bed at a cooling rate sufliciently slow to prevent distortion therein but at a rate sufficiently fast to produce a transformation of the structure of the steel to lower bainite and martensite and thereafter tempering the sections at a temperature below the critical temperature thereof.
5. A method of producing high-strength structural shapes such as beams, channels and angles comprising hot-rolling structural shapes from steel containing Percent Carbon About .15 Manganese About .26 Silicon About .21 Nickel About 2.95 Chromium About 1.83. Molybdenum About .48
with the balance iron and residual impurities, hot-roller straightening said sections at the finish of the hot-rolling and before the sections have cooled below an austenitizing temperature, air cooling said sections on a hot-bed to produce straight sections having a lower bainite, martensitic structure therein and then tempering said sections at a temperature of about 1225 F.
UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3, ll7 037 January 7, 1964 John M, Hodge corrected below.
Column 1 line 44, afte r "hardness?! insert --.durin'g column 4, line 6, for "1,75/
200" read 1. 70/2000 Signed and sealed this 26th day of May 1964..
(SEAL) Attest:
ERNEST W. SWIDER EDWARD J. BRENNER Attesting Officer Commissioner of Patents

Claims (1)

1. A METHOD OF PRODUCING HIGH STRENGTH STEEL STRUCTURAL SECTIONS SUCH AS BEAMS, CHANNELS AND ANGLES COMPRISING HOT-ROLLING SECTIONS OF LOW-CARBON STEEL HAVING SUFFICIENTLY HIGH HARDENABILITY THAT IT WILL HARDEN DURING AIR COOLING ON A HOT-BED, STRAIGHTENING SAID SECTIONS AFTER HOT-ROLLING AND PRIOR TO COOLING BELOW THE TEMPERATURE AT WHICH THE STEEL IS AUSTENITIC, AIR COOLING SAID SECTIONS TO ROOM TEMPERATURE ON A HOT-BED AT A RATE SUFFICIENTLY SLOW THAT DISTORTION DUE TO ABRUPT TRANSFORMATION DOES NOT OCCUR BUT AT A RATE SUFFICIENTLY FAST TO PRODUCE A MARTENSITIC-BAINITIC STRUCTURE THEREIN AND THEREAFTER TEMPERING SAID SECTIONS AT A TEMPERATURE BELOW THE LOWER CRITICAL TEMPERATURE THEREOF.
US139871A 1961-09-22 1961-09-22 Production of high strength steel structural shapes Expired - Lifetime US3117037A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US139871A US3117037A (en) 1961-09-22 1961-09-22 Production of high strength steel structural shapes

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US139871A US3117037A (en) 1961-09-22 1961-09-22 Production of high strength steel structural shapes

Publications (1)

Publication Number Publication Date
US3117037A true US3117037A (en) 1964-01-07

Family

ID=22488672

Family Applications (1)

Application Number Title Priority Date Filing Date
US139871A Expired - Lifetime US3117037A (en) 1961-09-22 1961-09-22 Production of high strength steel structural shapes

Country Status (1)

Country Link
US (1) US3117037A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4934566B1 (en) * 1968-03-14 1974-09-14

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US976891A (en) * 1906-02-01 1910-11-29 Adolph W Machlet Straightening and hardening apparatus.
GB344822A (en) * 1928-12-11 1931-03-11 Paul Pierre Marthourey Improvements relating to steel
US2003094A (en) * 1930-08-04 1935-05-28 Bethlehem Steel Corp Metal article and method of preparing same
US2087346A (en) * 1930-08-21 1937-07-20 United States Steel Corp Method of producing steel rails
US2088282A (en) * 1933-04-10 1937-07-27 Herman Johan Van Royen Process for the production of rails
GB472464A (en) * 1934-12-15 1937-09-16 Dortmund Hoerder Huettenver Ag An improved method of producing machine parts and work pieces from heat-treated steels

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US976891A (en) * 1906-02-01 1910-11-29 Adolph W Machlet Straightening and hardening apparatus.
GB344822A (en) * 1928-12-11 1931-03-11 Paul Pierre Marthourey Improvements relating to steel
US2003094A (en) * 1930-08-04 1935-05-28 Bethlehem Steel Corp Metal article and method of preparing same
US2087346A (en) * 1930-08-21 1937-07-20 United States Steel Corp Method of producing steel rails
US2088282A (en) * 1933-04-10 1937-07-27 Herman Johan Van Royen Process for the production of rails
GB472464A (en) * 1934-12-15 1937-09-16 Dortmund Hoerder Huettenver Ag An improved method of producing machine parts and work pieces from heat-treated steels

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4934566B1 (en) * 1968-03-14 1974-09-14

Similar Documents

Publication Publication Date Title
US1924099A (en) Thermally hardening steel
CN109252107B (en) Production method of high-flatness ultrahigh-strength steel
CN104513927A (en) High-strength high-rigidity steel plate with tensile strength of 800 MPa and preparation method thereof
CN108707823A (en) Ultrahigh-strength steel plates and preparation method thereof and unimach slab products
US4609410A (en) Method for producing high-strength deep-drawable dual-phase steel sheets
US3117037A (en) Production of high strength steel structural shapes
JPS6137334B2 (en)
JPS6358891B2 (en)
US3563813A (en) Controlling fracture toughness of high-strength stainless steels
CN114717393A (en) Rapid isothermal spheroidizing annealing method for 42CrMoA steel bar
US2924544A (en) Metallurgical process for cold-finishing steel
KR830004429A (en) Manufacturing method of spheroidized annealed steel wire
US3235413A (en) Method of producing steel products with improved properties
JPS55115924A (en) Production of high toughness high tensile steel plate
CN107419175B (en) Economical tool steel with good fatigue life and production method thereof
US2924543A (en) Cold-finished steels and method for manufacturing same
DE69719898T2 (en) Hot rolled steel sheet for deep drawing
US3196053A (en) Production of heat-treated sheets
JPS6057490B2 (en) Manufacturing method of high-strength steel plate with low yield ratio
US2779698A (en) Method of improving machinability of steel
JPS58141328A (en) Manufacture of high strength high toughness steel
JPS5842753A (en) High gamma value type high strength cold rolled steel plate having composite structure and its manufacture
JPH03207814A (en) Manufacture of low yield ratio high tensile strength steel plate
JPS6046318A (en) Preparation of steel excellent in sulfide cracking resistance
JPH01195242A (en) Manufacture of high tension steel plate having superior toughness at low temperature with uniformity in thickness direction