WO2013102986A1 - 高炭素熱延鋼板およびその製造方法 - Google Patents
高炭素熱延鋼板およびその製造方法 Download PDFInfo
- Publication number
- WO2013102986A1 WO2013102986A1 PCT/JP2012/008318 JP2012008318W WO2013102986A1 WO 2013102986 A1 WO2013102986 A1 WO 2013102986A1 JP 2012008318 W JP2012008318 W JP 2012008318W WO 2013102986 A1 WO2013102986 A1 WO 2013102986A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- less
- steel sheet
- rolled steel
- carbon hot
- ferrite
- Prior art date
Links
Images
Classifications
-
- 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
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- 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
-
- 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
- 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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/46—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for sheet metals
-
- 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
-
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
-
- 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
- C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
-
- 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
- C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
-
- 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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- 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
- C22C38/08—Ferrous alloys, e.g. steel alloys containing nickel
-
- 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
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/16—Ferrous alloys, e.g. steel alloys containing copper
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/32—Ferrous alloys, e.g. steel alloys containing chromium with boron
-
- 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
-
- 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
- C21D1/32—Soft annealing, e.g. spheroidising
-
- 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
- C21D2211/003—Cementite
-
- 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
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Definitions
- the present invention relates to a high carbon hot-rolled steel sheet having excellent cold workability and hardenability and a method for producing the same.
- Patent Document 2 by mass%, C: 0.15 to 0.40%, Si: 0.35% or less, Mn: 0.6 to 1.50%, P: 0.030% or less, S: 0.020% or less, sol.Al: 0.01 to 0.20% , N: 0.0020-0.012%, Ti: 0.005-0.1%, B: 0.0003-0.0030% and B ⁇ 0.0032-0.014 ⁇ sol.Al-0.029 ⁇ Ti are satisfied, and the balance is Fe and inevitable impurities.
- a method for producing a tempering-free Ti-B high carbon steel sheet excellent in cold workability, hardenability and toughness after heat treatment is disclosed.
- Patent Document 3 includes mass%, C: 0.20 to 0.48%, Si: 0.1% or less, Mn: 0.20 to 0.60%, P: 0.02% or less, S: 0.01% or less, sol.Al: 0.1% or less, N: 0.005% or less, Ti: 0.005-0.05%, B: 0.0005-0.003%, Cr: 0.05-0.3%, Ti- (48/14) N ⁇ 0.005, balance Fe and inevitable impurities composition and ferrite average High carbon hot rolling with excellent cold workability with a grain size of 6 ⁇ m or less, carbide average particle size of 0.1 ⁇ m or more and less than 1.20 ⁇ m, and a volume fraction of ferrite grains substantially free of carbides of 5% or less.
- a steel sheet is disclosed.
- Patent Documents 1 to 3 have a problem that stable and excellent cold workability and hardenability cannot be obtained.
- An object of the present invention is to provide a high carbon hot-rolled steel sheet that can stably obtain excellent cold workability and hardenability, and a method for producing the same.
- Stable and excellent cold workability can be obtained by using a microstructure composed of ferrite and cementite, an average particle diameter of ferrite of 10 to 20 ⁇ m, and a spheroidization rate of cementite of 90% or more.
- sol.Al By making the amount of sol.Al more than 0.10%, the effect of solid solution B (solute B) that improves hardenability can be effectively expressed, and stable hardenability can be obtained.
- the present invention has been made based on such findings, and in mass%, C: 0.20 to 0.48%, Si: 0.1% or less, Mn: 0.5% or less, P: 0.03% or less, S: 0.01% Below, sol.Al: more than 0.10% and 1.0% or less, N: 0.005% or less, B: 0.0005-0.0050%, the balance is composed of Fe and inevitable impurities, and the microstructure consists of ferrite and cementite A high carbon hot rolled steel sheet in which the average particle diameter of the ferrite is 10 to 20 ⁇ m and the spheroidization rate of the cementite is 90% or more is provided.
- At least one of Cu and Ni is 2% or less in total, and at least one of Cr and Mo in total It is preferable to add 1.0% or less and at least one of Sb and Sn in total or 0.1% or less together or individually.
- the high carbon hot rolled steel sheet of the present invention is a steel having the above composition, after rough rolling, finish rolling at a finishing temperature of 850 ° C. or higher, winding at a winding temperature of 600 ° C. or higher, It can be manufactured by annealing at an annealing temperature of 1 transformation point or less.
- the present invention it has become possible to produce a high carbon hot-rolled steel sheet capable of stably obtaining excellent cold workability and hardenability.
- the high carbon hot rolled steel sheet of the present invention is suitable for automobile gears, transmissions, seat recliners and the like.
- % which is a unit of component content, means “% by mass”.
- Composition C 0.20 ⁇ 0.48% C is an important element for obtaining strength after quenching.
- the C amount needs to be at least 0.20% or more.
- the C content is 0.20 to 0.48%.
- the C content is preferably 0.26% or more.
- Si 0.1% or less Si is an element that increases the strength by solid solution strengthening. However, if the Si content exceeds 0.1%, it hardens and cold workability deteriorates. Therefore, the Si content is 0.1% or less. There is no problem even if the amount of Si is zero.
- Mn 0.5% or less Mn is an element that increases the strength by solid solution strengthening. However, if the amount of Mn exceeds 0.5%, the hard workability or the band structure resulting from segregation is formed, so that the cold workability is deteriorated. Therefore, the Mn content is 0.5% or less, preferably 0.4% or less. There is no problem even if the amount of Mn is zero, but if Mn is reduced, graphite precipitates easily, so the amount of Mn is preferably 0.2% or more.
- P 0.03% or less
- P is an element that increases the strength by solid solution strengthening.
- the P content exceeds 0.03%, grain boundary embrittlement is caused and the toughness after quenching deteriorates. Therefore, the P content is 0.03% or less.
- the P content is preferably 0.02% or less.
- S 0.01% or less S is an element that must be reduced because it forms sulfides and degrades cold workability and toughness after quenching.
- the S content exceeds 0.01%, the cold workability and the toughness after quenching are remarkably deteriorated. Therefore, the S content is 0.01% or less.
- the S content is preferably 0.005% or less. There is no problem even if the amount of S is zero.
- sol.Al more than 0.10% and not more than 1.0% sol.Al promotes spheroidization of cementite and improves cold workability.
- the amount of sol.Al is 0.10% or less, it is heated in an atmosphere gas containing N 2 gas mixed to control the C potential in carburizing quenching or bright quenching.
- N 2 gas mixed to control the C potential in carburizing quenching or bright quenching.
- BN is easily formed, and the solid solution B that improves hardenability decreases, and the hardenability of the steel sheet surface layer portion may be significantly reduced.
- the amount of sol.Al exceeds 0.10%, AlN is preferentially formed and suppresses the formation of BN, so the austenite grains are refined by AlN formation, but the amount of solid solution B is secured, The hardenability can be expressed stably.
- the amount of sol.Al exceeds 1.0%, it becomes excessively hard due to solid solution strengthening and cold workability deteriorates.
- N 0.005% or less
- the N amount exceeds 0.005%, the amount of dissolved B decreases due to the formation of BN during heating in the quenching process, and austenite grains become too fine due to the formation of a large amount of BN and AlN, cooling. Sometimes the formation of ferrite is accelerated and the toughness after quenching deteriorates. Therefore, the N content is 0.005% or less. There is no problem even if the amount of N is zero.
- B 0.0005-0.0050%
- B is an important element that enhances hardenability. However, if the amount of B is less than 0.0005%, the effect of enhancing the sufficient hardenability is not recognized. On the other hand, if the amount of B exceeds 0.0050%, the hot rolling load becomes high, the operability is lowered, and the cold workability is deteriorated. Therefore, the B content is 0.0005 to 0.0050%.
- the balance is Fe and inevitable impurities, but in order to promote spheroidization of cementite and further improve cold workability and hardenability, a total of at least one of Cu and Ni is 2% or less, Cr In addition, it is preferable that at least one of Mo in total is 1.0% or less and at least one of Sb and Sn is contained in total or 0.1% or less together or individually. In addition, about Sb and Sn, the effect which improves hardenability by suppressing the nitridation of B was newly confirmed like the above-mentioned sol.Al. Therefore, it is particularly preferable to add these elements for the purpose of more surely improving the hardenability.
- Microstructure To obtain stable and excellent cold workability, it is necessary to use a microstructure composed of ferrite and cementite, to have an average ferrite grain size of 10 to 20 ⁇ m, and a cementite spheroidization ratio of 90% or more. There is. This is because when the average particle diameter of ferrite is less than 10 ⁇ m, it becomes hard, and when the average particle diameter of ferrite exceeds 20 ⁇ m, or when the spheroidization rate of cementite is less than 90%, ductility decreases even when softened. This is because the inter-workability deteriorates.
- the average grain size of the ferrite after polishing the plate thickness cross section in the rolling direction of the steel plate, corrodes nital, observe 10 locations near the center of the plate thickness with a scanning electron microscope at 1000 times, JIS The average particle diameter of ferrite at each location was determined by a cutting method based on G0552: 1998, and the average particle size at 10 locations was further averaged. At this time, the phase structure of the microstructure can be confirmed at the same time.
- the spheroidization rate of cementite is calculated by calculating the ratio a / b of the maximum diameter a and the minimum diameter b of each cementite by the above-mentioned structure observation, and the ratio of the number of cementites whose ratio is 3 or less to the total number of cementites (% ).
- the maximum diameter a and the minimum diameter b can be determined as shown in FIGS.
- the high carbon hot-rolled steel sheet of the present invention is obtained by hot rolling a steel having the above composition comprising rough rolling and finish rolling to obtain a steel sheet having a desired thickness.
- the finishing temperature is less than 850 ° C.
- the austenite grains become fine, and the average grain size of ferrite formed in the subsequent cooling process becomes less than 10 ⁇ m. Therefore, the finishing temperature is 850 ° C. or higher.
- the upper limit of the finishing temperature is not particularly specified, but if it is excessively high, the microstructure is likely to be mixed and unevenness in the hardenability is likely to occur.
- Winding temperature 600 ° C. or more
- the average grain size of ferrite is less than 10 ⁇ m. Therefore, the coiling temperature is 600 ° C. or higher.
- the upper limit of the coiling temperature is not particularly specified, but is preferably 750 ° C. in order to avoid deterioration of the surface properties due to the scale.
- Annealing temperature 680 ° C or more and Ac 1 transformation point or less
- the steel sheet after winding does not generate pearlite after pickling. Therefore, it is necessary to perform annealing at an annealing temperature not lower than 680 ° C. and not higher than the Ac 1 transformation point. If the annealing temperature is less than 680 ° C, the spheroidization rate of cementite cannot be increased to 90% or more, and if it exceeds the Ac 1 transformation point, austenite is generated during heating, pearlite is generated during cooling, and cold workability deteriorates. . Moreover, it is preferable that the annealing time maintained at said temperature is 20 hours or more and 40 hours or less.
- the annealing time is 20 hours or more, it is preferable because the spheroidization rate of the cementite is easily adjusted to a desired range, and if it is 40 hours or less, the effect of annealing is sufficiently obtained and the annealing is performed for a long time. This is preferable because an increase in manufacturing cost can be suppressed.
- the Ac 1 transformation point can be obtained, for example, by obtaining a thermal expansion curve in a formastar experiment at a heating rate of 100 ° C./hr and using the change point.
- Both converters and electric furnaces can be used to melt the high carbon steel of the present invention.
- the high carbon steel thus melted is made into a slab by ingot-bundling rolling or continuous casting.
- the slab is usually heated and then hot rolled.
- slab heating temperature 1280 degrees C or less in order to avoid the deterioration of the surface state by a scale.
- the material to be rolled may be heated by a heating means such as a sheet bar heater during hot rolling.
- the high carbon steel having the composition of steel numbers A to O shown in Table 1 is melted, then hot-rolled according to the hot rolling conditions shown in Table 2, pickled, and annealed at the annealing temperature shown in Table 2, Hot rolled annealed sheets (steel plates No. 1 to 18) with a thickness of 4.0 mm were manufactured.
- the phase structure of the microstructure, the average particle diameter of ferrite, and the spheroidization rate of cementite were determined by the above-described methods.
- JIS No. 5 test specimens were collected parallel to the rolling direction, and tensile strength and elongation were determined in accordance with JIS Z Z2201.
- hardenability was evaluated by the following method.
- Hardenability In an atmospheric gas in which a flat plate test piece (width 50 mm x length 50 mm) is taken from a steel plate, and the carbon potential is controlled to be equal to the amount of C in the steel by mixing air with RX gas Then, after heating and holding at 900 ° C. for 1 hour, a quenching test was conducted by a controlled atmosphere hardening in which the oil was immediately put into 50 ° C. oil and stirred, and the Rockwell hardness (H RC ) was measured. According to the amount of C in the steel, the hardenability is excellent when C: 0.20% and H RC ⁇ 42, C: 0.35% and H RC ⁇ 54, and C: 0.48% and H RC ⁇ 58.
- the steel sheet of the present invention has a microstructure composed of ferrite and cementite, the average grain size of ferrite is 10 to 20 ⁇ m, the spheroidization rate of cementite is 90% or more, high elongation and excellent cold workability. Moreover, after hardening, sufficient hardness is obtained according to the amount of C, and it turns out that it is excellent also in hardenability.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
C:0.20~0.48%
Cは、焼入れ後の強度を得るために重要な元素である。部品に冷間加工した後、熱処理によって所望の硬さを得るため、C量は少なくとも0.20%以上にする必要がある。しかし、C量が0.48%を超えると硬質化し、冷間加工性が劣化する。したがって、C量は0.20~0.48%とする。十分な熱処理後の硬さを得るには、C量は0.26%以上にすることが好ましい。
Siは、固溶強化により強度を上昇させる元素である。しかし、Si量が0.1%を超えると、硬質化し、冷間加工性が劣化する。したがって、Si量は0.1%以下とする。Si量はゼロであっても問題ない。
Mnは、固溶強化により強度を上昇させる元素である。しかし、Mn量が0.5%を超えると、硬質化したり、偏析に起因するバンド組織(band structure)が形成されるため、冷間加工性が劣化する。したがって、Mn量は0.5%以下、好ましくは0.4%以下とする。Mn量はゼロであっても問題ないが、Mnを低減するとグラファイト析出しやすくなるため、Mn量を0.2%以上にすることが好ましい。
Pは、固溶強化により強度を上昇させる元素である。しかし、P量が0.03%を超えると粒界脆化を招き、焼入れ後の靭性が劣化する。したがって、P量は0.03%以下とする。優れた焼入れ後の靭性を得るには、P量は0.02%以下にすることが好ましい。P量はゼロであっても問題ないが、過剰な低減は製造コストを高めるためコスト面を考慮するとP量を0.005%%以上にすることが好ましい。
Sは、硫化物を形成し、冷間加工性および焼入れ後の靭性を劣化させるため、低減しなければならない元素である。S量が0.01%を超えると、冷間加工性および焼入れ後の靭性が著しく劣化する。したがって、S量は0.01%以下とする。優れた冷間加工性および焼入れ後の靭性を得るには、S量は0.005%以下が好ましい。S量はゼロであっても問題ない。
sol.Alは、セメンタイトの球状化を促進し、冷間加工性を向上させる。しかし、Bを含有した鋼の場合、sol.Al量が0.10%以下だと、浸炭焼入れや光輝焼入れにおいてCポテンシャルを制御するために混合されたN2ガスを含むような雰囲気ガス中で加熱する時にBNが形成されやすく、焼入れ性を向上させる固溶Bが減少して鋼板表層部の焼入れ性が著しく低下する場合がある。sol.Al量を0.10%超えにすれば、AlNが優先的に形成されてBNの形成を抑制するので、AlN形成によりオーステナイト粒は微細化するが、固溶B量が確保されているため、焼入れ性を安定して発現できることになる。一方、sol.Al量が1.0%を超えると、固溶強化により過度に硬質化し、冷間加工性が劣化する。
N量が0.005%を超えると、焼入れ処理の加熱時に、BNの形成により固溶B量が低下し、また、多量のBNやAlNの形成によりオーステナイト粒が微細化し過ぎ、冷却時にフェライトの生成が促進され、焼入れ後の靭性が劣化する。したがって、N量は0.005%以下とする。N量はゼロであっても問題ない。
Bは、焼入れ性を高める重要な元素である。しかし、B量が0.0005%未満では、十分な焼入れ性を高める効果が認められない。一方、B量が0.0050%を超えると、熱間圧延の負荷が高くなり操業性が低下するととともに、冷間加工性の劣化も招く。したがって、B量は0.0005~0.0050%とする。
安定して優れた冷間加工性を得るには、フェライトとセメンタイトからなるミクロ組織とし、かつフェライトの平均粒径を10~20μm、セメンタイトの球状化率を90%以上にする必要がある。これは、フェライトの平均粒径が10μm未満では硬質化する、また、フェライトの平均粒径が20μmを超えたり、セメンタイトの球状化率が90%未満では軟質化しても延性が低下するので、冷間加工性が劣化するためである。
仕上温度:850℃以上
本発明の高炭素熱延鋼板は、上記のような組成の鋼を粗圧延と仕上圧延からなる熱間圧延して所望の板厚の鋼板とされる。このとき、仕上温度が850℃未満では、オーステナイト粒が微細になるため、その後の冷却過程で形成されるフェライトの平均粒径が10μm未満になる。したがって、仕上温度は850℃以上とする。なお、仕上温度の上限は、特に規定しないが、過度に高いと、ミクロ組織が混粒化して焼入れ性にムラが生じやすくなる場合があるので、1000℃にすることが好ましい。
巻取温度が600℃未満では、フェライトの平均粒径が10μm未満になる。したがって、巻取温度は600℃以上とする。なお、巻取温度の上限は、特に規定しないが、スケールによる表面性状の劣化を避けるために、750℃にすることが好ましい。
巻取り後の鋼板には、酸洗後、パーライトを生成させず、フェライトとセメンタイトからなるミクロ組織とし、かつセメンタイトの球状化率を90%以上にするため、680℃以上Ac1変態点以下の焼鈍温度で焼鈍を行う必要がある。焼鈍温度が680℃未満ではセメンタイトの球状化率を90%以上にできず、Ac1変態点を超えると加熱中にオーステナイトが生じて、冷却中にパーライトが生成し、冷間加工性が劣化する。また、上記の温度に維持される焼鈍時間は20時間以上40時間以下であることが好ましい。焼鈍時間が20時間以上であればセメンタイトの球状化率を所望の範囲に調整しやすいという理由で好ましく、40時間以下であれば焼鈍の効果が充分に得られるとともに、焼鈍を長時間行うことによる製造コストの上昇も抑えられるという理由で好ましい。
Claims (5)
- 質量%で、C:0.20~0.48%、Si:0.1%以下、Mn:0.5%以下、P:0.03%以下、S:0.01%以下、sol.Al:0.10%超え1.0%以下、N:0.005%以下、B:0.0005~0.0050%を含有し、残部がFeおよび不可避的不純物からなる組成を有し、フェライトとセメンタイトからなるミクロ組織を有し、前記フェライトの平均粒径が10~20μmであり、前記セメンタイトの球状化率が90%以上である高炭素熱延鋼板。
- さらに、質量%で、Cu、Niのうちの少なくとも1種を合計で2%以下含有する請求項1に記載の高炭素熱延鋼板。
- さらに、質量%で、Cr、Moのうちの少なくとも1種を合計で1.0%以下含有する請求項1または2に記載の高炭素熱延鋼板。
- さらに、質量%で、Sb、Snのうちの少なくとも1種を合計で0.1%以下含有する請求項1から3のいずれか1項に記載の高炭素熱延鋼板。
- 請求項1から4のいずれか1項に記載の組成を有する鋼を、粗圧延後、850℃以上の仕上温度で仕上圧延し、600℃以上の巻取温度で巻取った後、680℃以上Ac1変態点以下の焼鈍温度で焼鈍する高炭素熱延鋼板の製造方法。
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
KR20147021554A KR20140110994A (ko) | 2012-01-05 | 2012-12-26 | 고탄소 열연 강판 및 그 제조 방법 |
CN201280066106.0A CN104040000B (zh) | 2012-01-05 | 2012-12-26 | 高碳热轧钢板及其制造方法 |
JP2013552352A JP5590254B2 (ja) | 2012-01-05 | 2012-12-26 | 高炭素熱延鋼板およびその製造方法 |
IN1297KON2014 IN2014KN01297A (ja) | 2012-01-05 | 2012-12-26 | |
EP12864620.5A EP2801636B1 (en) | 2012-01-05 | 2012-12-26 | High carbon hot-rolled steel sheet and method for producing same |
US14/370,314 US10077491B2 (en) | 2012-01-05 | 2012-12-26 | High carbon hot rolled steel sheet and method for manufacturing the same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2012000407 | 2012-01-05 | ||
JP2012-000407 | 2012-01-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2013102986A1 true WO2013102986A1 (ja) | 2013-07-11 |
Family
ID=48745062
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2012/008318 WO2013102986A1 (ja) | 2012-01-05 | 2012-12-26 | 高炭素熱延鋼板およびその製造方法 |
Country Status (8)
Country | Link |
---|---|
US (1) | US10077491B2 (ja) |
EP (1) | EP2801636B1 (ja) |
JP (1) | JP5590254B2 (ja) |
KR (1) | KR20140110994A (ja) |
CN (1) | CN104040000B (ja) |
IN (1) | IN2014KN01297A (ja) |
TW (1) | TWI510643B (ja) |
WO (1) | WO2013102986A1 (ja) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015004902A1 (ja) * | 2013-07-09 | 2015-01-15 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
WO2015146173A1 (ja) * | 2014-03-28 | 2015-10-01 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
WO2015146174A1 (ja) * | 2014-03-28 | 2015-10-01 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
JP2016216809A (ja) * | 2015-05-26 | 2016-12-22 | 新日鐵住金株式会社 | 冷間成形性と熱処理後靭性に優れた低炭素鋼板及び製造方法 |
JP6587038B1 (ja) * | 2018-10-02 | 2019-10-09 | 日本製鉄株式会社 | 浸炭用鋼板、及び、浸炭用鋼板の製造方法 |
Families Citing this family (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140332122A1 (en) * | 2012-01-06 | 2014-11-13 | Jfe Steel Corporation | High carbon hot rolled steel sheet and method for manufacturing the same (as amended) |
KR101799712B1 (ko) | 2013-11-22 | 2017-11-20 | 신닛테츠스미킨 카부시키카이샤 | 고탄소 강판 및 그 제조 방법 |
KR101975136B1 (ko) | 2015-03-13 | 2019-05-03 | 제이에프이 스틸 가부시키가이샤 | 고강도 냉연 강판 및 그 제조 방법 |
MX2017015016A (es) * | 2015-05-26 | 2018-04-13 | Nippon Steel & Sumitomo Metal Corp | Placa de acero y metodo de produccion de la misma. |
MX2020007992A (es) | 2018-01-30 | 2020-09-09 | Jfe Steel Corp | Lamina de acero laminada en caliente con alto contenido en carbono y metodo para la produccion de la misma. |
CN113366137B (zh) * | 2019-01-30 | 2022-10-28 | 杰富意钢铁株式会社 | 高碳热轧钢板及其制造方法 |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS598356A (ja) | 1982-07-06 | 1984-01-17 | Nec Corp | 半導体集積回路装置の製造方法 |
JPH04124216A (ja) * | 1990-09-12 | 1992-04-24 | Sumitomo Metal Ind Ltd | 成形性の良好な高炭素薄鋼板の製造方法 |
JPH04311546A (ja) * | 1991-04-11 | 1992-11-04 | Kawasaki Steel Corp | 加工性と焼入れ性に優れた鋼材及びその製造方法 |
JPH08120405A (ja) * | 1994-10-19 | 1996-05-14 | Sumitomo Metal Ind Ltd | 穴拡げ性と二次加工性に優れた高炭素薄鋼板及びその製造方法 |
JP2002309345A (ja) * | 2001-02-07 | 2002-10-23 | Nkk Corp | 焼入れ後の衝撃特性に優れる薄鋼板およびその製造方法 |
JP2005097740A (ja) | 2003-08-28 | 2005-04-14 | Jfe Steel Kk | 高炭素熱延鋼板およびその製造方法 |
JP4265582B2 (ja) | 2001-02-07 | 2009-05-20 | Jfeスチール株式会社 | 焼入れ後の衝撃特性に優れる熱延鋼板およびその製造方法 |
Family Cites Families (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH04265582A (ja) | 1991-02-20 | 1992-09-21 | Mitsubishi Electric Corp | 磁気ディスク装置 |
JPH0598356A (ja) | 1991-10-04 | 1993-04-20 | Sumitomo Metal Ind Ltd | 焼き戻し省略型Ti−B系高炭素薄鋼板の製造方法 |
JP2718332B2 (ja) * | 1992-09-29 | 1998-02-25 | 住友金属工業株式会社 | 成形性の良好な高炭素鋼帯の製造方法 |
JPH08291362A (ja) * | 1995-04-21 | 1996-11-05 | Sumitomo Metal Ind Ltd | 冷間加工性に優れた鋼材 |
JP2001011575A (ja) * | 1999-06-30 | 2001-01-16 | Nippon Steel Corp | 冷間加工性に優れた機械構造用棒鋼・鋼線及びその製造方法 |
KR100513991B1 (ko) * | 2001-02-07 | 2005-09-09 | 제이에프이 스틸 가부시키가이샤 | 박강판의 제조방법 |
US20050199322A1 (en) * | 2004-03-10 | 2005-09-15 | Jfe Steel Corporation | High carbon hot-rolled steel sheet and method for manufacturing the same |
JP5050433B2 (ja) * | 2005-10-05 | 2012-10-17 | Jfeスチール株式会社 | 極軟質高炭素熱延鋼板の製造方法 |
JP5292698B2 (ja) * | 2006-03-28 | 2013-09-18 | Jfeスチール株式会社 | 極軟質高炭素熱延鋼板およびその製造方法 |
JP5076347B2 (ja) * | 2006-03-31 | 2012-11-21 | Jfeスチール株式会社 | ファインブランキング加工性に優れた鋼板およびその製造方法 |
JP5458649B2 (ja) | 2009-04-28 | 2014-04-02 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
JP5056876B2 (ja) * | 2010-03-19 | 2012-10-24 | Jfeスチール株式会社 | 冷間加工性と焼入れ性に優れた熱延鋼板およびその製造方法 |
-
2012
- 2012-12-26 KR KR20147021554A patent/KR20140110994A/ko not_active Application Discontinuation
- 2012-12-26 CN CN201280066106.0A patent/CN104040000B/zh active Active
- 2012-12-26 WO PCT/JP2012/008318 patent/WO2013102986A1/ja active Application Filing
- 2012-12-26 US US14/370,314 patent/US10077491B2/en active Active
- 2012-12-26 IN IN1297KON2014 patent/IN2014KN01297A/en unknown
- 2012-12-26 EP EP12864620.5A patent/EP2801636B1/en active Active
- 2012-12-26 JP JP2013552352A patent/JP5590254B2/ja active Active
- 2012-12-28 TW TW101150792A patent/TWI510643B/zh not_active IP Right Cessation
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS598356A (ja) | 1982-07-06 | 1984-01-17 | Nec Corp | 半導体集積回路装置の製造方法 |
JPH04124216A (ja) * | 1990-09-12 | 1992-04-24 | Sumitomo Metal Ind Ltd | 成形性の良好な高炭素薄鋼板の製造方法 |
JPH04311546A (ja) * | 1991-04-11 | 1992-11-04 | Kawasaki Steel Corp | 加工性と焼入れ性に優れた鋼材及びその製造方法 |
JPH08120405A (ja) * | 1994-10-19 | 1996-05-14 | Sumitomo Metal Ind Ltd | 穴拡げ性と二次加工性に優れた高炭素薄鋼板及びその製造方法 |
JP2002309345A (ja) * | 2001-02-07 | 2002-10-23 | Nkk Corp | 焼入れ後の衝撃特性に優れる薄鋼板およびその製造方法 |
JP4265582B2 (ja) | 2001-02-07 | 2009-05-20 | Jfeスチール株式会社 | 焼入れ後の衝撃特性に優れる熱延鋼板およびその製造方法 |
JP2005097740A (ja) | 2003-08-28 | 2005-04-14 | Jfe Steel Kk | 高炭素熱延鋼板およびその製造方法 |
Cited By (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2015004902A1 (ja) * | 2013-07-09 | 2015-01-15 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
US10400298B2 (en) | 2013-07-09 | 2019-09-03 | Jfe Steel Corporation | High-carbon hot-rolled steel sheet and method for producing the same |
JP6065121B2 (ja) * | 2014-03-28 | 2017-01-25 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
CN106133169A (zh) * | 2014-03-28 | 2016-11-16 | 杰富意钢铁株式会社 | 高碳热轧钢板及其制造方法 |
KR20160138230A (ko) * | 2014-03-28 | 2016-12-02 | 제이에프이 스틸 가부시키가이샤 | 고탄소 열연 강판 및 그 제조 방법 |
WO2015146174A1 (ja) * | 2014-03-28 | 2015-10-01 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
JP6065120B2 (ja) * | 2014-03-28 | 2017-01-25 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
EP3091097A4 (en) * | 2014-03-28 | 2017-03-08 | JFE Steel Corporation | High-carbon hot-rolled steel sheet and method for producing same |
KR101892524B1 (ko) | 2014-03-28 | 2018-08-28 | 제이에프이 스틸 가부시키가이샤 | 고탄소 열연 강판 및 그 제조 방법 |
WO2015146173A1 (ja) * | 2014-03-28 | 2015-10-01 | Jfeスチール株式会社 | 高炭素熱延鋼板およびその製造方法 |
US10844454B2 (en) | 2014-03-28 | 2020-11-24 | Jfe Steel Corporation | High-carbon hot-rolled steel sheet and method for manufacturing the same |
JP2016216809A (ja) * | 2015-05-26 | 2016-12-22 | 新日鐵住金株式会社 | 冷間成形性と熱処理後靭性に優れた低炭素鋼板及び製造方法 |
JP6587038B1 (ja) * | 2018-10-02 | 2019-10-09 | 日本製鉄株式会社 | 浸炭用鋼板、及び、浸炭用鋼板の製造方法 |
WO2020070810A1 (ja) * | 2018-10-02 | 2020-04-09 | 日本製鉄株式会社 | 浸炭用鋼板、及び、浸炭用鋼板の製造方法 |
Also Published As
Publication number | Publication date |
---|---|
EP2801636A1 (en) | 2014-11-12 |
CN104040000B (zh) | 2016-09-07 |
EP2801636A4 (en) | 2015-08-05 |
JP5590254B2 (ja) | 2014-09-17 |
JPWO2013102986A1 (ja) | 2015-05-11 |
US20150090376A1 (en) | 2015-04-02 |
KR20140110994A (ko) | 2014-09-17 |
EP2801636B1 (en) | 2018-08-01 |
US10077491B2 (en) | 2018-09-18 |
IN2014KN01297A (ja) | 2015-10-16 |
CN104040000A (zh) | 2014-09-10 |
TW201337002A (zh) | 2013-09-16 |
TWI510643B (zh) | 2015-12-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP5590254B2 (ja) | 高炭素熱延鋼板およびその製造方法 | |
EP2589678B1 (en) | High-strength steel sheet with excellent processability and process for producing same | |
JP5458649B2 (ja) | 高炭素熱延鋼板およびその製造方法 | |
JP6017341B2 (ja) | 曲げ性に優れた高強度冷延鋼板 | |
US10400299B2 (en) | High-carbon hot-rolled steel sheet and method for manufacturing the same | |
JP2017048412A (ja) | 溶融亜鉛めっき鋼板、合金化溶融亜鉛めっき鋼板、およびそれらの製造方法 | |
TWI433960B (zh) | 加工性和點熔接性優異之高強度熔融鍍鋅鋼板及其製造方法 | |
WO2019077777A1 (ja) | 高強度鋼板およびその製造方法 | |
JP6065120B2 (ja) | 高炭素熱延鋼板およびその製造方法 | |
JP6065121B2 (ja) | 高炭素熱延鋼板およびその製造方法 | |
WO2016024371A1 (ja) | 高強度鋼板の製造方法 | |
JP5644966B2 (ja) | 焼入れ性に優れる面内異方性の小さい高炭素熱延鋼板およびその製造方法 | |
WO2015004902A1 (ja) | 高炭素熱延鋼板およびその製造方法 | |
JP5302840B2 (ja) | 伸びと伸びフランジ性のバランスに優れた高強度冷延鋼板 | |
JP5958668B1 (ja) | 高強度鋼板およびその製造方法 | |
WO2019131099A1 (ja) | 熱延鋼板およびその製造方法 | |
US11248275B2 (en) | Warm-workable high-strength steel sheet and method for manufacturing the same | |
JP5565532B2 (ja) | 高炭素熱延鋼板およびその製造方法 | |
JP6275560B2 (ja) | 衝突特性に優れる超高強度鋼板 | |
JP4329804B2 (ja) | 形状及び加工性に優れる高強度熱延鋼板 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 12864620 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2013552352 Country of ref document: JP Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2012864620 Country of ref document: EP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 14370314 Country of ref document: US |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: 20147021554 Country of ref document: KR Kind code of ref document: A |