US3839095A - Method of making a drawing steel sheet by continuous annealing process including shelf treatment therein - Google Patents

Method of making a drawing steel sheet by continuous annealing process including shelf treatment therein Download PDF

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Publication number
US3839095A
US3839095A US00238459A US23845972A US3839095A US 3839095 A US3839095 A US 3839095A US 00238459 A US00238459 A US 00238459A US 23845972 A US23845972 A US 23845972A US 3839095 A US3839095 A US 3839095A
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temperature
making
sec
steel sheet
cooling
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US00238459A
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H Kubotera
K Nakaoka
K Watanabe
T Kurihara
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JFE Engineering Corp
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Nippon Kokan Ltd
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    • 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0447—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the heat treatment
    • C21D8/0473—Final recrystallisation annealing
    • 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
    • C21D8/04—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing
    • C21D8/0421—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips to produce plates or strips for deep-drawing characterised by the working steps
    • C21D8/0426—Hot rolling

Definitions

  • ABSTRACT A soft steel sheet, in which C content is 0.02 to 0.10 percent, manufactured with a continuous annealing process comprising the following steps; heating the cold reduced steel strip up to the range of recrystalli- Mar. 27, 1971 Japan 46-18137 Zetierr temperature to 850C, Slew-Cooling from Said temperature to the range of A point to 600C and [52] U.S. Cl. 148/2, 148/12 then ap g f m said temperature to the nor- [51] Int.
  • Such steel sheet is economical in cost because of 3,245,844 4/1966 Weber 148/12 hlgh productwlty' 3,320,099 5/1967 Weber 148/12 8 Claims, 5 Drawing Figures PAIENTEDIET H914 Z I I0 002 004 00s ma 0/0 02 METHOD OF MAKING A DRAWING STEEL SHEET BY CONTINUOUS ANNEALING PROCESS INCLUDING SHELF TREATMENT TI-IEREIN
  • This invention relates to a method of making a drawing steel sheet by continuous annealing process including novel shelf treatment therein, and more particularly making drawing steel sheet with very high productivity.
  • This art was developed .to give drawability of some degree to a galvanized steel strip.
  • the features of the above art lie in quenching from the range of about 1,250F and l,300F to below l,000F, following by holding at said annealing temperature for 30 seconds and then holding for at least 30 seconds in the shelf temperature range of 800 to 1,000F. With such a process, the steel sheet becomes softer than that from the ordinary continuous annealing process. According to our experiments, it has been confirmed that the softness and aging resistance, so far attained, are not yet sufficient.
  • the shelf treatment as mentioned above should be further improved if the steel is subjected to press-forming services.
  • productivity based on the above art is inferior to that of an ordinary continuous annealing operation.
  • the steel treated by the above art can be subjected to press-forming services only with difficulty.
  • a steel which can be subjected to ordinary press-forming services is not yet available.
  • This invention has been developed to remove the above-mentioned faults and disadvantages.
  • the featurcs of this invention consist in heating the cold reduced steel up to the range of recrystallization temperature to 850C, cooling slowly from said temperature to the range of less than A, point to 600C and then cooling rapidly at the rate of 200C/sec and l0,000C/sec to the normal temperature, and again heating the steel up to the range of 300 to 530C and holding for at least seconds.
  • the Further object of this invention is to provide a method of making a drawing steel sheet by a continuous annealing process displaying very high productivity, accordingly, low cost.
  • FIG. 1 is an example of typical annealing cycle of this invention
  • FIG. 2 shows an annealing cycle based on this invention in comparison with other cycles
  • FIG. 3 is a graph showing the relation between yield stress and carbon content in steel
  • FIG. 4 is a graph showing the relation between aging index and carbon content in steel
  • FIG. 5 illustrates changing behavior of aging index and yield stress with various velocities.
  • T, T T and T points on the time-temperature diagram of FIG. 1 show the maximum heating temperature, rapid-cooling starting temperature, the maximum heating temperature for the precipitation treatment and finishing temperature of said precipitation treatment respectively.
  • Said T, point is the maximum heating temperature and is selected from the range of recrystallization temperature to 850C.
  • T point is the rapid-cooling starting temperature and is selected from the range of A, point to 600C. In such a case, when said T, point is more than 850C, the heating will be difficult to be carried out with the ordinary continuous annealing facilities.
  • the heating is fully within the region of austenization, consequently the lowering of known Lankford Value r will be brought about. Therefore, the upper limit of said heating temperature is 850C.
  • T point is more than A, point, a known tempering structure is produced partially because of the rapid-cooling and successive precipitation treatment, consequently a harmful influence on ductility of steel tends to occur, while the rapid-cooling from less than 600C results in causing the amount of solution carbon to decrease.
  • said rapid-cooling starting temperature should be selected from the range of A, point and 600C.
  • the steel strip is cooled slowly from said T, point to T point. And the slow-cooling time should be sufficient to bring a solution of carbon in equilibrium state.
  • the slowly cooled steel to said T point is rapidly cooled from the temperature to the normal temperature.
  • Such rapid-cooling operation is carried out to increase the amount of super-saturated carbon and number of precipitating nuclei with a velocity of 200C/sec and l0,000C/sec, which is a desirable requirement for the next rapid precipitation treatment of the carbide.
  • said steel is heated up to T point.
  • Said T,, point is the maximum heating temperature for precipitation treatment of carbide and is selected from the range of 300 to 530C.
  • T, point is a finishing temperature of said precipitation treatment.
  • Such T point is the same temperature as said T point, i.e., a holding operation, or lower temperature than said T point, i.e., slow cooling operation.
  • said operation time from T to T should be for at least 10 seconds.
  • T and T points are limited as mentioned above is as follows: that is, when said treating temperature is above 530C, the solution degree of carbon tends to increase, and conversely when said temperature is below 300C, said precipitating velocity EXAMPLE 1 Making requirements:
  • the above-mentioned shelf treatment carried out at a temperature between 300C and 530C may secure the same degree of aging index as that of an ordinary batch type annealing process, it will be, however, recommended that the starting temperature of said precipitation treatment is 350C to 450C (T and the finishing temperature is 300C (T).
  • T the starting temperature of said precipitation treatment
  • 300C the finishing temperature
  • this process is characterised by having the solution carbon brought in the equilibrium state during slow-cooling from T, point to T point, supersaturated during rapid-cooling from T point to the normal temperature and precipitated as carbide during successive shelf treatment from T;, point to T point.
  • Chemical composition of the present steel will not be especially specified except carbon content, which is from no less than 0.02 percent to no more than 0.10 percent.
  • the reason that only the carbon content is limited as mentioned above is as follows; when C content is less than 0.02 percent, said aging index does not lower as much as expected because of a small amount of supersaturated carbon after said rapid-cooling, and when C content is more than 0.10 percent, said steel is too hard and unsuitable for press-forming operation.
  • the annealing process of this invention may be included in the process of ordinary cold reducing steel strip which is a serial process comprising steel making, slabbing or continuous casting, hot rolling, picking and cold reducing. However, when a steel exhibiting lower,
  • said steel should be coiled at a temperature of more than about 630 C following the hot rolling step. It is confirmed that the high temperature coiling step causes crystal Steel of making slabbing hot rolling finishing temperature: 865C coiling temperature: 600C last thickness: 2.8mm Cold reducing after pickling cold reducing rate: 71.4 percent last thickness: 0.8mm Continuous annealing cycle: A, B, C, D and E cycles as shown in FIG. 2
  • next air-cooling cycle B This is a cycle based on this invention.
  • said yield stress of the steels treated with said cycle B lowers by about 2Kg/mm and said aging index lowers by about 0.5Kg/mm in comparison with that of cycle A.
  • the properties of steels treated with said cycles C and D are superior to those of said A and inferior to those of said cycle B.
  • this invention process is cooled slowly from the maximum heating-up temperature to rapid-cooling starting temperature in the range of A, point to 600C, cooled rapidly from said starting temperature to the normal temperature and then cooled slowly the maximum reheating-up temperature to finishing temperature of said shelf treatment.
  • EXAMPLE III Steel V among steels of the above Table l is tested.
  • the object of this test lies in investingating influences to which a cooling rate of from said soaking temperature, i.e., T point, to the normal temperature gives said properties of the steel.
  • T point a cooling rate of from said soaking temperature
  • the hot rolling and cold reducing requirements on the above steel are the same as that of Example ll. But continuous annealing process was carried out depending upon said Cycle A as shown in Example I. That is;
  • a method of making a drawing steel sheet comprising the following steps:
  • shelf-treating in which said strip is reheated up to the range of 300C and 530C, successively cooled slowly from said temperature to at least 300C,
  • a method of making a drawing steel sheet as set forth in claim 1 wherein said continuous annealing is carried out with which said strip is heated up at about 800C, cooled slowly to about 650C by the rate of 5C/sec and then cooled rapidly from said temperature to the normal temperature by about 600C/sec and in successive shelf treatment said strip is heated up to 530C and 500C and then cooled slowly to 300C by the rate of about 12C/sec, next air-cooled.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Heat Treatment Of Sheet Steel (AREA)
US00238459A 1971-03-27 1972-03-27 Method of making a drawing steel sheet by continuous annealing process including shelf treatment therein Expired - Lifetime US3839095A (en)

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JP1813771A JPS5413403B1 (de) 1971-03-27 1971-03-27

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JP (1) JPS5413403B1 (de)
DE (1) DE2214896B2 (de)
FR (1) FR2132090B1 (de)
GB (1) GB1389078A (de)
IT (1) IT953565B (de)
NL (1) NL155597C (de)
ZA (1) ZA722060B (de)

Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3936324A (en) * 1975-03-14 1976-02-03 Nippon Kokan Kabushiki Kaisha Method of making high strength cold reduced steel by a full continuous annealing process
US3988174A (en) * 1972-04-03 1976-10-26 Nippon Steel Corporation Hot rolled steel sheet having excellent workability and method thereof
US3988173A (en) * 1972-04-03 1976-10-26 Nippon Steel Corporation Cold rolled steel sheet having excellent workability and method thereof
US4023987A (en) * 1974-12-20 1977-05-17 Toyo Kohan Co., Ltd. Method of producing soft thin steel sheet by continuous annealing
US4040873A (en) * 1975-08-23 1977-08-09 Nippon Kokan Kabushiki Kaisha Method of making low yield point cold-reduced steel sheet by continuous annealing process
US4050959A (en) * 1974-11-18 1977-09-27 Nippon Kokan Kabushiki Kaisha Process of making a high strength cold reduced steel sheet having high bake-hardenability and excellent non-aging property
US4066474A (en) * 1974-01-31 1978-01-03 Nippon Kokan Kabushiki Kaisha Method of making high strength cold reduced steel by continuous annealing process
US4113517A (en) * 1974-04-26 1978-09-12 Nippon Kokan Kabushiki Kaisha Method of making cold-reduced al-killed steel strip for press-forming by continuous casting and continuous annealing process
US4113523A (en) * 1973-07-25 1978-09-12 Nippon Kokan Kabushiki Kaisha Process of making high tension cold-reduced al-killed steel excellent in accelerated aging property
US4116729A (en) * 1977-09-09 1978-09-26 Nippon Steel Corporation Method for treating continuously cast steel slabs
US4145235A (en) * 1972-12-28 1979-03-20 Nippon Steel Corporation Process for producing cold rolled steel sheet and strip having improved cold formabilities
US4191600A (en) * 1977-05-02 1980-03-04 Centre De Recherches Metallurgiques-Centrum Voor Research In De Metallurgie Method of continuously heat-treating steel sheet or strip
US4323403A (en) * 1972-06-22 1982-04-06 Nippon Kokan Kabushiki Kaisha Continuous annealing method for cold reduced steel strip
US4374682A (en) * 1979-02-02 1983-02-22 Nippon Steel Corporation Process for producing deep-drawing cold rolled steel strips by short-time continuous annealing
US4391653A (en) * 1980-09-25 1983-07-05 Nippon Steel Corporation Process for producing cold rolled steel strip having excellent mechanical strength and useful for motor vehicles
US4698102A (en) * 1984-07-09 1987-10-06 Nippon Steel Corporation Process for producing, by continuous annealing, soft blackplate for surface treatment
US5405463A (en) * 1980-10-24 1995-04-11 Nippon Kokan Kabushiki Kaisha Continuous annealing process of producing cold rolled mild steel sheet excellent in deep drawability and aging resistibility
FR2850671A1 (fr) * 2003-02-05 2004-08-06 Usinor Procede de fabrication d'une bande d'acier dual-phase a structure ferrito-martensitique, laminee a froid et bande obtenue

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0075292B2 (de) * 1981-09-18 1993-11-24 Nippon Steel Corporation Verfahren zur Herstellung eines kaltgewalzten Stahlbleches
DE3841870A1 (de) * 1988-12-13 1990-06-21 Westfalenstahl Kalt Und Profil Stahl zur herstellung von stahlbaendern fuer die fertigung von schattenmasken

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3245844A (en) * 1962-07-25 1966-04-12 United States Steel Corp Hot rolled steel strip
US3320099A (en) * 1964-08-12 1967-05-16 United States Steel Corp Method of processing steel
US3513036A (en) * 1967-05-02 1970-05-19 Inland Steel Co Process for producing coiled,hotrolled,pickled steel strip
US3657022A (en) * 1965-08-10 1972-04-18 Nippon Kokan Kk Process for the manufacture of cold-rolled steel strip with superior mechanical workability, especially deep forming properties

Family Cites Families (1)

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DE2212711A1 (de) * 1972-03-16 1973-09-27 Bosch Gmbh Robert Blockierschutz-einrichtung

Patent Citations (4)

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Publication number Priority date Publication date Assignee Title
US3245844A (en) * 1962-07-25 1966-04-12 United States Steel Corp Hot rolled steel strip
US3320099A (en) * 1964-08-12 1967-05-16 United States Steel Corp Method of processing steel
US3657022A (en) * 1965-08-10 1972-04-18 Nippon Kokan Kk Process for the manufacture of cold-rolled steel strip with superior mechanical workability, especially deep forming properties
US3513036A (en) * 1967-05-02 1970-05-19 Inland Steel Co Process for producing coiled,hotrolled,pickled steel strip

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
Richards, P. N.; Short Time Annealing Characteristics of Capped, Rimmed, and Semi Killed Wide Strip; Spec. Rep. No. 67; The Iron & Steel Inst., May, 1960, pp. 118 127. *

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3988174A (en) * 1972-04-03 1976-10-26 Nippon Steel Corporation Hot rolled steel sheet having excellent workability and method thereof
US3988173A (en) * 1972-04-03 1976-10-26 Nippon Steel Corporation Cold rolled steel sheet having excellent workability and method thereof
US4323403A (en) * 1972-06-22 1982-04-06 Nippon Kokan Kabushiki Kaisha Continuous annealing method for cold reduced steel strip
US4145235A (en) * 1972-12-28 1979-03-20 Nippon Steel Corporation Process for producing cold rolled steel sheet and strip having improved cold formabilities
US4113523A (en) * 1973-07-25 1978-09-12 Nippon Kokan Kabushiki Kaisha Process of making high tension cold-reduced al-killed steel excellent in accelerated aging property
US4066474A (en) * 1974-01-31 1978-01-03 Nippon Kokan Kabushiki Kaisha Method of making high strength cold reduced steel by continuous annealing process
US4113517A (en) * 1974-04-26 1978-09-12 Nippon Kokan Kabushiki Kaisha Method of making cold-reduced al-killed steel strip for press-forming by continuous casting and continuous annealing process
US4050959A (en) * 1974-11-18 1977-09-27 Nippon Kokan Kabushiki Kaisha Process of making a high strength cold reduced steel sheet having high bake-hardenability and excellent non-aging property
US4023987A (en) * 1974-12-20 1977-05-17 Toyo Kohan Co., Ltd. Method of producing soft thin steel sheet by continuous annealing
US3936324A (en) * 1975-03-14 1976-02-03 Nippon Kokan Kabushiki Kaisha Method of making high strength cold reduced steel by a full continuous annealing process
US4040873A (en) * 1975-08-23 1977-08-09 Nippon Kokan Kabushiki Kaisha Method of making low yield point cold-reduced steel sheet by continuous annealing process
US4191600A (en) * 1977-05-02 1980-03-04 Centre De Recherches Metallurgiques-Centrum Voor Research In De Metallurgie Method of continuously heat-treating steel sheet or strip
US4116729A (en) * 1977-09-09 1978-09-26 Nippon Steel Corporation Method for treating continuously cast steel slabs
US4374682A (en) * 1979-02-02 1983-02-22 Nippon Steel Corporation Process for producing deep-drawing cold rolled steel strips by short-time continuous annealing
US4391653A (en) * 1980-09-25 1983-07-05 Nippon Steel Corporation Process for producing cold rolled steel strip having excellent mechanical strength and useful for motor vehicles
US5405463A (en) * 1980-10-24 1995-04-11 Nippon Kokan Kabushiki Kaisha Continuous annealing process of producing cold rolled mild steel sheet excellent in deep drawability and aging resistibility
US4698102A (en) * 1984-07-09 1987-10-06 Nippon Steel Corporation Process for producing, by continuous annealing, soft blackplate for surface treatment
FR2850671A1 (fr) * 2003-02-05 2004-08-06 Usinor Procede de fabrication d'une bande d'acier dual-phase a structure ferrito-martensitique, laminee a froid et bande obtenue
WO2004079022A1 (fr) * 2003-02-05 2004-09-16 Usinor Procede de fabrication d'une bande d'acier dual-phase a structure ferrito-martensitique, laminee a froid et bande obtenue
US20060144482A1 (en) * 2003-02-05 2006-07-06 Antoine Moulin Method of producing a cold-rolled band of dual-phase steel with a ferritic/martensitic structure and band thus obtained
CN100465299C (zh) * 2003-02-05 2009-03-04 于西纳公司 生产冷轧铁素体/马氏体双相钢带的方法及由此得到的带材

Also Published As

Publication number Publication date
ZA722060B (en) 1972-12-27
DE2214896B2 (de) 1975-09-11
NL7204052A (de) 1972-09-29
DE2214896A1 (de) 1972-10-12
NL155597C (nl) 1978-06-15
FR2132090B1 (de) 1974-08-02
FR2132090A1 (de) 1972-11-17
IT953565B (it) 1973-08-10
GB1389078A (en) 1975-04-03
JPS5413403B1 (de) 1979-05-30

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