WO2010055609A1 - 高強度厚鋼板およびその製造方法 - Google Patents
高強度厚鋼板およびその製造方法 Download PDFInfo
- Publication number
- WO2010055609A1 WO2010055609A1 PCT/JP2009/005315 JP2009005315W WO2010055609A1 WO 2010055609 A1 WO2010055609 A1 WO 2010055609A1 JP 2009005315 W JP2009005315 W JP 2009005315W WO 2010055609 A1 WO2010055609 A1 WO 2010055609A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- less
- mpa
- strength
- tensile strength
- steel
- 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
- C22C38/16—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
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B66—HOISTING; LIFTING; HAULING
- B66C—CRANES; LOAD-ENGAGING ELEMENTS OR DEVICES FOR CRANES, CAPSTANS, WINCHES, OR TACKLES
- B66C23/00—Cranes comprising essentially a beam, boom, or triangular structure acting as a cantilever and mounted for translatory of swinging movements in vertical or horizontal planes or a combination of such movements, e.g. jib-cranes, derricks, tower cranes
- B66C23/62—Constructional features or details
-
- 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
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- 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
- 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
- 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
- C22C38/04—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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with 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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
-
- 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
- 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
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
-
- 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
Definitions
- the present invention is used for structural members of construction machinery and industrial machinery, has excellent delayed fracture resistance and weldability, has high yield strength of 1300 MPa or more and tensile strength of 1400 MPa or more, and has a thickness of 4.5 mm or more and 25 mm or less.
- the present invention relates to a certain high-strength thick steel plate and a manufacturing method thereof. This application claims priority based on Japanese Patent Application No. 2008-288859 filed in Japan on November 11, 2008, the contents of which are incorporated herein by reference.
- Patent Document 1 discloses a method for producing a steel plate having a tensile strength of 1370 to 1960 N / mm 2 and excellent hydrogen embrittlement resistance. Yes.
- the technique of Patent Document 1 relates to a cold-rolled steel sheet having a thickness of 1.8 mm, and is premised on a high cooling rate of 70 ° C./sec or higher, and no consideration is given to weldability.
- Patent document 2 is an example of the technique.
- the prior austenite crystal grain size needs to be 5 ⁇ m or less in order to improve the delayed fracture resistance.
- Each of the techniques disclosed in Patent Document 2 is a technique for refining the prior austenite crystal grain size by rapid heating before quenching.
- special heating equipment is required, so that the technology is difficult to realize.
- hardenability is reduced as crystal grains are refined, an extra alloy element is required to ensure strength. Therefore, excessive grain refinement is not preferable from the viewpoints of weldability and economy.
- Patent Document 3 and Patent Document 4 disclose wear-resistant steel having excellent delayed fracture resistance.
- the tensile strengths of Patent Document 3 and Patent Document 4 are 1400 MPa to 1500 MPa and 1450 MPa to 1600 MPa, respectively.
- neither Patent Document 3 nor Patent Document 4 describes the yield stress. Since hardness is an important factor for wear resistance, tensile strength affects wear resistance. However, since the yield strength does not significantly affect the wear resistance, the yield strength is usually not considered in the wear resistant steel. Therefore, it is thought that the steel materials described in these documents are not suitable as structural members for construction machines and industrial machines.
- Patent Document 5 delayed fracture resistance of a high-strength bolt steel material having a yield strength of 1300 MPa is improved by elongation of prior austenite grains and rapid tempering.
- rapid heating and tempering is difficult with normal thick plate heat treatment equipment, application to thick steel plates is difficult.
- Patent Document 6 discloses a technique of adding a large amount of Ni in order to increase the weather resistance of steel and suppress delayed fracture of bolt parts. However, since 2.3% or more of expensive Ni is added as an essential condition, application to a thick plate is not practical from the viewpoint of cost.
- Patent Document 7 discloses a technique of simultaneously adding P and Cu in order to densify the generated rust and improve the delayed fracture resistance.
- P is increased, toughness tends to decrease. Therefore, it is difficult to secure a balance between strength and toughness in a high strength thick steel plate with a yield strength of 1300 MPa class, so this technique cannot be applied.
- JP-A-7-90488 Japanese Patent Laid-Open No. 11-80903 JP-A-11-229075 Japanese Unexamined Patent Publication No. 1-149921 JP-A-9-263876 JP 2001-107139 A JP-A-9-316011
- An object of the present invention is to provide a high-strength thick steel plate for a structural member having a delayed fracture resistance, bending workability and weldability excellent in delayed fracture resistance, bending workability and weldability, and a tensile strength of 1400 MPa or more, which are used for structural members of construction machinery and industrial machinery. Is to provide a method.
- the most economical means for obtaining a high strength having a yield strength of 1300 MPa or more and a tensile strength of 1400 MPa or more is to make the steel structure martensite by quenching heat treatment from a constant temperature.
- the hardenability and cooling rate of the steel must be appropriate.
- the plate thickness of thick steel plates used as structural members for construction machines and industrial machines is mostly 25 mm or less. In the case of a plate thickness of 25 mm, the average cooling rate at the plate thickness center portion during quenching heat treatment by water cooling is usually 20 ° C./sec or more.
- the martensite structure in the present invention is a structure that is considered to be substantially full martensite after quenching. Specifically, the martensite structure fraction is 90% or more, and the structure fraction other than martensite such as retained austenite, ferrite, and bainite is less than 10%. When the martensite structure fraction is low, an extra alloy element is required to obtain a certain strength.
- the inventor has developed y-type welding as defined in JIS Z 3158 for various steel sheets having a plate thickness of 25 mm, a prior austenite grain size number of 7 to 11, a yield strength of 1300 MPa or more and a tensile strength of 1400 MPa or more.
- a crack test was carried out to investigate the relationship between the weld crack sensitivity index Pcm and the preheating temperature. The result is shown in FIG. In order to reduce the welding load, it is desirable that the preheating temperature is as low as possible.
- the crack stop preheating temperature that is, the preheating temperature at which the root cracking rate becomes 0 is set to 175 ° C. or less.
- the Pcm for the root crack rate to be completely 0 at a preheating temperature of 175 ° C. is 0.39% or less, and this Pcm was used as a guideline for the upper limit of the alloy addition amount.
- the weld crack is greatly influenced by the preheating temperature, and FIG. 1 shows the relationship between the weld crack and the preheating temperature.
- Pcm needs to be 0.39% or less.
- Pcm needs to be 0.37% or less.
- the delayed fracture resistance of martensitic steel greatly depends on the strength. If the tensile strength exceeds 1200 MPa, delayed fracture may occur. Furthermore, the sensitivity to delayed fracture increases as the strength increases.
- As a means for improving the delayed fracture resistance of martensitic steel there is a method of refining the prior austenite grain size as described above. However, since the hardenability decreases as the crystal grains become finer, a larger amount of alloy element is required to ensure the strength. Therefore, from the viewpoint of weldability and economy, a lower limit of the grain size due to crystal grain refinement may be set. For example, the austenite grain size number described later may be 12 or less.
- the delayed fracture resistance was evaluated by the “limit diffusible hydrogen content” which is the upper limit of the hydrogen content that does not break in the delayed fracture test. This method is disclosed in Iron and Steel, Vol. 83 (1997), p454. Specifically, after adding various amounts of diffusible hydrogen to a sample with a notch having the shape shown in FIG. 2 by round bar electrolytic hydrogen charging, the surface of the sample is plated to remove hydrogen. The scattering was prevented. The test piece was held under a predetermined load in the atmosphere, and the time until delayed fracture occurred was measured. The load stress in the delayed fracture test was 0.8 times the tensile strength of each steel material.
- FIG. 3 is an example of the relationship between the amount of diffusible hydrogen and the fracture time until delayed fracture.
- the time until delayed fracture increases. Also, if the amount of diffusible hydrogen is below a certain value, delayed fracture will not occur.
- the integrated value of the hydrogen amount measured by collecting the test piece immediately after the test and raising the temperature to 400 ° C. under a temperature rising condition of 100 ° C./hr by a gas chromatograph is defined as “diffusible hydrogen amount”. Further, the limit amount of hydrogen at which the test piece does not break is defined as “limit diffusible hydrogen amount Hc”.
- the delayed fracture resistance is considered to be high.
- HE is reduced by the addition of Cu.
- HE is more significantly reduced by addition of Cu exceeding 1.0%.
- HE tends to become large, so that content is high.
- FIG. 7 shows a change in tensile strength and prior austenite grain size for martensitic steel containing 1.20 to 1.55% Cu and 0.002 to 0.004% P. It is the result of investigation.
- Hc / HE when Hc / HE is larger than 3, it is evaluated that the delayed fracture resistance is good.
- Hc / HE> 3 is indicated by ⁇
- Hc / HE ⁇ 3 is indicated by ⁇ . From FIG.
- the delayed fracture resistance is well organized by tensile strength and prior austenite grain number (N ⁇ ). That is, while lowering HE by adding Cu and reducing P, Hc is increased and Hc / HE is increased by controlling the tensile strength and the prior austenite grain size within a certain range. This control shows that the delayed fracture resistance can be reliably improved without relying on excessive crystal grain refinement.
- a range satisfying (a) and (b) is indicated by a region surrounded by a thick line in FIG.
- the strength of martensitic steel is greatly affected by the C content and the tempering temperature. Therefore, in order to obtain a yield strength of 1300 MPa or more and a tensile strength of 1400 MPa or more and 1650 MPa or less, it is necessary to appropriately select the amount of C and the tempering temperature. 8 and 9 show the influence of the C content and the tempering temperature on the yield strength and tensile strength of martensitic steel, respectively.
- the tempering heat treatment is not performed, that is, in the as-quenched state, the yield ratio of the martensite structure is low. Therefore, the tensile strength is high, but the yield strength is low.
- the C content needs to be about 0.24% or more.
- the yield ratio can be increased without a decrease in toughness.
- the inventors have found that it is possible to achieve both a high yield strength of 1300 MPa or more and a tensile strength of 1400 MPa or more and 1650 MPa or less with a small addition amount of alloy elements.
- the inventor can easily and stably obtain polygonal sizing of the prior austenite grain size number satisfying the above (a) and (b) by the following production method.
- I got the knowledge that I can. That is, an appropriate amount of Nb is added to the steel sheet, and an appropriate controlled rolling is performed during hot rolling to introduce an appropriate working strain to the steel sheet before quenching. Thereafter, reheating and quenching is performed within a range of heating temperature of Ac3 transformation point + 20 ° C.
- FIG. 10 shows an example of the relationship between the quenching heating temperature (reheating temperature) and the prior austenite grain size.
- the gist of the present invention is as follows.
- the plate thickness may be 4.5 mm or more and 25 mm or less.
- a steel slab or cast slab having the composition described in (1) or (2) above is heated to 1100 ° C. or higher; 930 ° C. so that the steel sheet has a thickness of 4.5 mm or more and 25 mm or less.
- hot rolling is performed in which the cumulative rolling reduction in the temperature range of 860 ° C. or more is 30% or more and 65% or less and the rolling is finished at 860 ° C. or more; after cooling, the steel sheet is subjected to Ac 3 transformation point + 20 ° C. Then, reheating to a temperature of 870 ° C. or lower; thereafter, accelerated cooling to 200 ° C. or lower under cooling conditions in which the average cooling rate at the plate thickness center portion of the steel sheet from 600 ° C.
- 300 ° C. is 20 ° C./sec or higher. And then performing a tempering heat treatment in a temperature range of 200 ° C. or higher and 300 ° C. or lower; and a method for producing a high-strength thick steel plate.
- a high-strength thick steel plate having a yield strength of 1300 MPa or more and a tensile strength of 1400 MPa or more, which is excellent in delayed fracture resistance, bending workability and weldability, used for structural members of construction machinery and industrial machinery is economically provided. can do.
- the C content is determined as an amount necessary for obtaining a yield strength of 1300 MPa or more and a tensile strength of 1400 MPa or more and 1650 MPa or less when the martensite structure fraction is 90% or more. .
- the range of C content is 0.18% or more and 0.23% or less. When the C content is less than 0.18%, the steel sheet does not have a predetermined strength. On the other hand, if the amount of C exceeds 0.23%, the strength of the steel sheet is too high or the workability deteriorates.
- the lower limit of the C amount may be limited to 0.19%, and the upper limit of the C amount may be limited to 0.22% or 0.21%.
- Si acts as a deoxidizing material and a strengthening element, and its effect is recognized with addition of 0.1% or more.
- the Ac3 point Ac3 transformation point
- the toughness may be impaired. Therefore, the upper limit of Si content is 0.5%.
- the lower limit of Si content may be limited to 0.15% or 0.20%, and the upper limit of Si content may be limited to 0.40% or 0.30%.
- Mn is an element effective for improving hardenability and improving strength, and also has an effect of lowering the Ac3 point. Therefore, at least 1.0% or more of Mn is added. However, if the amount of Mn exceeds 2.0%, segregation is promoted and toughness and weldability may be impaired. Therefore, 2.0% is made the upper limit of Mn addition. To ensure strength and improve toughness, the lower limit of the Mn amount is 1.1%, 1.2 or 1.3%, and the upper limit of the Mn amount is 1.9%, 1.8% or 1.7%. You may restrict.
- P is a harmful element that greatly reduces the delayed fracture resistance as an impurity.
- the P content be 0.020% or less.
- the P content is 0.010% or less.
- the P content may be limited to 0.008% or less, 0.006% or less, or 0.004% or less.
- the S content is suppressed to 0.010% or less.
- the amount of S may be limited to 0.006% or less or 0.003% or less.
- Cu is an element that reduces the amount of invading hydrogen HE from the environment and improves delayed fracture resistance. As shown in FIG. 5, HE is reduced by adding Cu exceeding 0.5%. Furthermore, HE is more significantly reduced by adding Cu exceeding 1.0%. Therefore, the amount of Cu added is more than 0.50%, preferably more than 1.0%. However, if Cu is added over 3.0%, weldability may be reduced. Therefore, the addition amount of Cu is set to 3.0 or less. In order to improve delayed fracture resistance, the lower limit of the Cu content may be limited to 0.7%, 1.0%, or 1.2%. In order to improve weldability, the upper limit of Cu content may be limited to 2.2%, 1.8%, or 1.6%.
- Ni is an element that improves hardenability and toughness. Moreover, there is an effect of suppressing cracking of the slab due to the addition of high Cu by adding Ni that is approximately half of the Cu addition amount by mass%. Therefore, Ni is added at least 0.25% or more. In order to exhibit this effect stably, the amount of Ni may be limited to 0.5% or more, 0.8% or more, or 0.9% or more. However, since Ni is an expensive element, the addition amount is set to 2.0% or less. For further price reduction, the Ni content may be limited to 1.6% or less or 1.3% or less.
- Nb has the effect of generating fine carbides during rolling to widen the non-recrystallization temperature range to enhance the controlled rolling effect and to introduce appropriate strain into the rolled structure before quenching.
- the pinning effect has the effect of suppressing austenite coarsening during quenching heating. Therefore, Nb is an essential element for obtaining the predetermined prior austenite grain size in the present invention. Therefore, Nb is added at 0.003% or more. In order to stably obtain these effects, Nb may be limited to 0.005% or more, 0.008% or more, or 0.011% or more. However, if added excessively, weldability may be hindered, so the added amount is made 0.10% or less. In order to improve weldability, it may be limited to 0.05% or less, 0.03% or less, or 0.02% or less.
- Al is added in an amount of 0.05% or more for the purpose of fixing N in order to secure free B necessary for improving hardenability.
- excessive addition of Al may reduce toughness, so the upper limit of Al content is 0.15%.
- the upper limit of the Al content may be limited to 0.10% or 0.08%.
- B is an essential element effective for enhancing hardenability.
- the amount of B needs to be 0.0003% or more.
- the B amount is set to 0.0003% or more and 0.0030% or less.
- the lower limit of B content is limited to 0.0005% or 0.0008%
- the upper limit of B content is limited to 0.0021% or 0.0015%. May be.
- the toughness is lowered and BN is formed to inhibit the effect of improving the hardenability of B. Therefore, the N content is suppressed to 0.006% or less.
- a steel containing the above elements and the balance being Fe and inevitable impurities is the basic composition of the steel of the present invention.
- one or more of Cr, Mo, and V can be added in addition to the above components.
- Cr improves hardenability and is effective in improving strength. Therefore, you may add 0.05% or more of Cr.
- excessive addition of Cr may reduce toughness. Therefore, the addition of Cr is 1.5% or less.
- the Cr content may be limited to 1.0% or less, 0.5% or less, or 0.4% or less.
- Mo improves hardenability and is effective for improving strength. Therefore, you may add 0.03% or more of Mo.
- the effect of precipitation strengthening cannot be expected under the production conditions of the present invention having a low tempering temperature, the effect of improving the strength is limited even if a large amount of Mo is added.
- Mo is also an expensive element, the addition of Mo is set to 0.5% or less. If necessary, the upper limit of the Mo amount may be limited to 0.35% or 0.20% or less.
- V also improves hardenability and is effective in improving strength. Therefore, you may add 0.01% or more of V.
- the effect of precipitation strengthening cannot be expected under the production conditions of the present invention having a low tempering temperature, the effect of improving the strength is limited even if a large amount of V is added.
- V is an expensive element, the addition of V is set to 0.10% or less. If necessary, the V amount may be limited to 0.08% or less, 0.06% or less, or 0.04% or less.
- the component composition in order to ensure weldability as described above, is limited such that Pcm represented by the following formula (1) is 0.39% or less. In order to further improve the weldability, the content may be limited to 0.38% or less or 0.37% or less.
- the carbon equivalent Ceq represented by the following formula (2) may be 0.80 or less.
- Ceq [C] + [Si] / 24 + [Mn] / 6 + [Ni] / 40 + [Cr] / 5 + [Mo] / 4 + [V] / 14 (2)
- hot rolling is performed by heating a steel slab or slab having the above steel composition.
- the heating temperature is 1100 ° C. or higher so that Nb is sufficiently dissolved.
- appropriate particle size control is performed so that the prior austenite particle size number is 7.0 or more. Therefore, it is necessary to perform appropriate controlled rolling at the time of hot rolling, introduce an appropriate working strain to the steel sheet before quenching, and set the quenching heating temperature within the range of Ac3 transformation point + 20 ° C. to 870 ° C. It is.
- the controlled rolling at the time of hot rolling rolling is performed so that the cumulative reduction ratio in the temperature range of 930 ° C. or lower and 860 ° C. or higher is 30% or higher and 65% or lower, and the rolling is finished at 860 ° C. or higher and the sheet thickness is 4 A thick steel plate of 5 mm to 25 mm.
- the purpose of this controlled rolling is to introduce an appropriate working strain into the steel sheet before reheating and quenching.
- the said temperature range of controlled rolling is a non-recrystallization temperature range of the steel of the present invention in which an appropriate amount of Nb is contained. If the cumulative rolling reduction in this non-recrystallization temperature region is less than 30%, the processing strain is insufficient.
- the austenite at the time of reheating becomes coarse. Further, if the cumulative rolling reduction in the non-recrystallization temperature region exceeds 65% or the rolling end temperature is 860 ° C. or less, the working strain becomes excessive. In this case, the austenite at the time of heating may become a mixed grain structure. Therefore, even if the quenching heating temperature is within the following appropriate range, a sized structure having a prior austenite grain size number of 7.0 or more may not be obtained.
- the steel sheet After hot rolling, the steel sheet is cooled, reheated to a temperature of Ac3 transformation point + 20 ° C. or higher and 870 ° C. or lower, and then subjected to quenching heat treatment for accelerated cooling to 200 ° C. or lower.
- the quenching heating temperature must naturally be higher than the Ac3 transformation point. However, if the heating temperature is just above the Ac3 transformation point, the structure becomes mixed and appropriate particle size control may not be possible. Polygonal (isotropic) sizing cannot be reliably obtained unless the quenching heating temperature is higher than the Ac3 transformation point + 20 ° C. Therefore, in order to set the quenching heating temperature to 870 ° C. or less, the Ac 3 transformation point of the steel material needs to be 850 ° C.
- the steel sheet In cooling by quenching heat treatment, the steel sheet is acceleratedly cooled to 200 ° C. or less under the condition that the average cooling rate from 600 ° C. to 300 ° C. at the center of the plate thickness is 20 ° C./sec or more.
- the average cooling rate from 600 ° C. to 300 ° C. at the center of the plate thickness is 20 ° C./sec or more.
- a martensitic structure having a structure fraction of 90% or more can be obtained in a steel sheet having a thickness of 4.5 mm or more and 25 mm or less. Since the cooling rate at the center of the plate thickness cannot be directly measured, it is calculated by heat transfer calculation from the plate thickness, surface temperature, and cooling conditions.
- tempering heat treatment is performed in a temperature range of 200 ° C. or higher and 300 ° C. or lower for the purpose of increasing the yield strength by the aging effect.
- the tempering temperature is less than 200 ° C., there is no aging effect and the yield strength does not increase.
- the tempering temperature exceeds 300 ° C., the toughness decreases due to temper embrittlement. Therefore, the tempering heat treatment is performed at 200 ° C. or higher and 300 ° C. or lower.
- the time for the tempering heat treatment may be about 15 minutes or more.
- Steel pieces A to AF having the composition shown in Tables 1 and 2 were melted to obtain steel pieces. From these steel slabs, steel plates having a thickness of 4.5 to 25 mm were manufactured according to the manufacturing conditions of Examples 1 to 14 of the present invention shown in Table 3 and Comparative Examples of 15 to 46 shown in Table 5. . These steel sheets were evaluated for yield strength, tensile strength, prior austenite grain number, martensite structure fraction, weld crackability, bending workability, delayed fracture resistance, and toughness. Table 4 shows the results of Examples 1 to 14 of the present invention, and Table 6 shows the results of Comparative Examples 15 to 46. Further, the Ac3 transformation point was measured.
- the yield strength and the tensile strength were measured by taking a No. 1A tensile test piece specified in JIS Z 2201 and performing a tensile test specified in JIS Z 2241.
- the yield strength passed 1300 MPa or more, and the tensile strength passed 1400-1650 MPa.
- the prior austenite particle size number was measured by the method of JIS G 0551 (2005), and it was considered acceptable when the tensile strength and the prior austenite particle size number satisfy the above (a) and (b).
- five fields of 20 ⁇ m ⁇ 30 ⁇ m range were observed with a transmission electron microscope using a sample collected from the vicinity of the center of the plate thickness with a transmission electron microscope.
- the area of the martensite structure in each field of view was measured, and the martensite structure fraction was calculated from the average value of each area.
- the martensite structure has a high dislocation density, and very little cementite is produced by tempering heat treatment at 300 ° C. or lower. Therefore, the martensite structure can be distinguished from the bainite structure.
- the y-type weld cracking test specified in JIS Z 3158 was used.
- the plate thickness of the steel plate used for evaluation was 25 mm except for Examples 2, 4, 8, and 11, and CO 2 welding with a heat input of 15 kJ / cm was performed.
- JIS Z 2201 No. 4 Charpy test specimens were sampled from the center of the plate thickness at right angles to the rolling direction, and three specimens were subjected to Charpy impact tests at -20 ° C. The average value of the absorbed energy of each test piece was calculated, and the average value was 27 J or more.
- a 5 mm sub-size Charpy test piece was used for a steel plate having a thickness of 8 mm (Example 11), and a 3 mm sub-size Charpy test piece was used for a steel plate having a thickness of 4.5 mm (Example 4).
- the target value was an absorbed energy value of 27 J or more when it was assumed that the plate width of the No. 4 Charpy test piece (that is, plate width 10 mm).
- a c3 transformation point, using Formastor-FII Fuji Telecommunications Koki was determined by the thermal expansion measured at a heating rate conditions at 2.5 ° C. / min.
- Examples 1 to 14 of the present invention in Tables 3 and 4 the yield strength, tensile strength, prior austenite grain number, martensite structure fraction, weld crackability, bending workability, delayed fracture resistance, toughness All target values are satisfied.
- Comparative Examples 15 to 34 in Table 5 and Table 6 the chemical components indicated by the underline in the table depart from the range limited by the present invention. Therefore, in Comparative Examples 15 to 34, the yield strength, tensile strength, prior austenite grain size number, martensite structure fraction, weld crackability, bending workability, delayed fracture resistance, despite being within the range of the production conditions of the present invention. One or more of characteristics and toughness does not meet the target value.
- Comparative Example 35 the steel component composition is within the range of the present invention, but the Pcm value deviates from the range of the present invention, so the weld crackability is unacceptable.
- Comparative Example 36 the steel component composition is within the range of the present invention, but the Ac3 point departs from the range of the present invention, so the quenching heating temperature cannot be lowered. Therefore, refinement
- Comparative Examples 37-46 the steel chemical composition, Pcm values, also A c3 point are all be within the scope the present invention, does not satisfy the production conditions of the present invention.
- At least one of yield strength, tensile strength, prior austenite grain size number, martensite structure fraction, weld crackability, bending workability, delayed fracture resistance, and toughness does not meet the target value. That is, in Comparative Example 37, since the heating temperature is low and Nb does not dissolve, the austenite is not sufficiently refined. Therefore, the comparative example 37 is unacceptable for delayed fracture resistance. In Comparative Example 38, since the cumulative rolling reduction at 930 ° C. or lower and 860 ° C. or higher is low, the austenite is not sufficiently refined. Therefore, the delayed fracture resistance is unacceptable. In Comparative Example 39, since the quenching heating temperature exceeds 880 ° C., the austenite is not sufficiently refined. Therefore, the delayed fracture resistance is unacceptable.
- Comparative Example 40 since the cooling rate from 600 ° C. to 300 ° C. is small, a martensite structure fraction of 90% or more cannot be obtained. For this reason, the resulting yield strength is low, which is unacceptable. Since the comparative example 41 is not tempered, the yield strength is low and it is not acceptable. Since the tempering temperature exceeds 300 degreeC, the comparative example 42 has low toughness and is disqualified. Since the comparative example 43 has higher tempering temperature than the comparative example 42, intensity
- Comparative Example 45 since the rolling end temperature is low, the austenite is not sufficiently refined. For this reason, Comparative Example 45 fails the delayed fracture resistance.
- Comparative Example 46 since the accelerated cooling end temperature is high, quenching is insufficient and a martensite structure fraction of 90% or more cannot be obtained. Therefore, Comparative Example 46 has a low tensile strength and is rejected. In Comparative Example 46, the steel sheet was accelerated to 300 degrees, then cooled to 200 ° C., and tempered to 250 ° C.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Heat Treatment Of Steel (AREA)
- Metal Rolling (AREA)
Abstract
Description
本願は、2008年11月11日に、日本に出願された特願2008-288859号に基づき優先権を主張し、その内容をここに援用する。
溶接割れは、予熱温度の影響が大きく、図1には、溶接割れと予熱温度との関係を示している。前述のように150℃の予熱温度においてルート割れが完全に0となるためには、Pcmが0.39%以下であることが必要である。150℃の予熱温度においてルート割れが完全に0となるためには、Pcmが0.37%以下であることが必要である。
HEに対するCuおよびPの影響を、それぞれ、図5および図6に示す。図5に示すように、Cu添加によりHEが低下する。特に、1.0%を超えるCuの添加によってより顕著にHEが低下する。また、図6に示すように、Pについては、含有量が高いほどHEが大きくなる傾向がある。
すなわち、Cu添加およびP低減によりHEを低くしながら、引張強度と旧オーステナイト粒径とを一定の範囲に制御することによってHcを高くし、Hc/HEを大きくする。このような制御によって、過度の結晶粒微細化に頼ることなく、耐遅れ破壊特性を確実に向上できることを示している。
(a) 引張強度が1400MPa以上、1550MPa未満の場合は、Nγ≧([TS]-1400)×0.006+7.0
(b) 引張強度が1550MPa以上、1650MPa以下の場合は、Nγ≧([TS]-1550)×0.01+7.9
ここで、[TS]は、引張強度(MPa)、Nγは、旧オーステナイト結晶粒度番号である。(a)、(b)を満たす範囲は、図7中の太線で囲まれた領域で示される。なお、旧オーステナイト結晶粒度番号は、JIS G 0551(2005)(ISO 643)の方法で測定した。すなわち、旧オーステナイト結晶粒度番号は、試料片断面の1mm2当りの平均結晶粒数mを用いて、Nγ=-3+log2mにより算出される。
また、1650MPaを超えると曲げ加工性が大きく低下するので、引張強度の上限を1650MPaとする。
焼戻し熱処理をしない場合、すなわち焼入れたままの状態では、マルテンサイト組織の降伏比は低い。そのため、引張強度は高い反面、降伏強度が低くなる。降伏強度を1300MPa以上とするためには、C量は、およそ0.24%以上が必要である。しかしながら、このC量では引張強度1650MPa以下を満たすことが難しい。
一方、450℃以上で焼戻し熱処理されたマルテンサイト組織では、降伏比は増加するが、引張強度が大きく低下する。1400MPa以上の引張強度を確保するには、C量をおよそ0.35%以上とする必要がある。しかしながら、このC量では、溶接性を確保するためにPcmを0.39%以下とすることは困難である。
マルテンサイト組織鋼を200℃以上、300℃以下の低温で焼戻し熱処理することにより、引張強度をあまり低下させないで降伏比を高めることができる。この場合には、上記の降伏強度1300MPa以上、かつ引張強度1400MPa以上1650MPa以下の条件を満たすことが可能となる。
また、マルテンサイト組織鋼を300℃超、450℃未満程度の温度で焼戻した場合、いわゆる低温焼戻し脆化により靭性が低下する問題がある。しかしながら、焼戻し温度が200℃以上、300℃以下であれば、この焼戻し脆化は生じないので、靭性低下は問題とならない。
以上のことから、適切なC量と合金元素を含有するマルテンサイト組織鋼を200℃以上300℃以下の低温で焼き戻すことにより、靭性低下を伴うことなく降伏比を上昇させることができ、比較的少ない合金元素添加量で、1300MPa以上の高い降伏強度と、1400MPa以上、1650MPa以下の引張強度を両立させることができるという知見を得るに至った。
本発明の要旨は、下記のとおりである。
まず、本発明の鋼成分の限定理由を述べる。
Crは、焼入性を向上させ、強度向上に有効である。そのため、Crを0.05%以上添加してもよい。しかしながら、Crを過剰に添加すると靭性を低下させることがある。そのため、Crの添加は、1.5%以下とする。靭性向上のために、Cr量を1.0%以下、0.5%以下または0.4%以下に制限してもよい。
Pcm=[C]+[Si]/30+[Mn]/20+[Cu]/20+[Ni]/60+[Cr]/20+[Mo]/15+[V]/10+5[B]・・・(1)
ここで、[C]、[Si]、[Mn]、[Cu]、[Ni]、[Cr]、[Mo]、[V]、[B]は、それぞれ、C、Si、Mn、Cu、Ni、Cr、Mo、V、Bの質量%である。
Ceq=[C]+[Si]/24+[Mn]/6+[Ni]/40+[Cr]/5+[Mo]/4+[V]/14・・・(2)
まず、上記の鋼成分組成の鋼片または鋳片を加熱して熱間圧延を行う。加熱温度は、Nbが十分固溶するように、1100℃以上とする。
さらに、旧オーステナイト粒度番号7.0以上への適度な粒径制御を行う。そのため、熱間圧延時に適度な制御圧延を行って、焼入れ前の鋼板に適度な加工歪を導入し、焼入れ加熱温度をAc3変態点+20℃以上、かつ870℃以下の範囲とすることが必要である。
これらの鋼板について、降伏強度、引張強度、旧オーステナイト粒度番号、マルテンサイト組織分率、溶接割れ性、曲げ加工性、耐遅れ破壊特性、靭性を評価した。表4に1~14の本発明の実施例の結果を、表6に15~46の比較例の結果を示している。また、Ac3変態点を実測した。
旧オーステナイト粒度番号は、JIS G 0551(2005)の方法で測定し、引張強度と旧オーステナイト粒度番号とが、前記(a)、(b)を満たす場合に合格とした。
マルテンサイト組織分率の評価のために、板厚中心部付近から採取したサンプルを用いて、透過型電子顕微鏡により、倍率5000倍で20μm×30μmの範囲を5視野観察した。それぞれの視野におけるマルテンサイト組織の面積を測定し、それぞれの面積の平均値からマルテンサイト組織分率を算出した。この際、マルテンサイト組織は、転位密度が高く、300℃以下の焼戻し熱処理ではセメンタイトはごくわずかしか生成しない。そのため、マルテンサイト組織をベイナイト組織などと区別できる。
溶接割れ性の評価のために、JIS Z 3158に規定のy型溶接割れ試験で評価を行った。評価に供する鋼板の板厚は、実施例2、4、8、11を除きすべて25mmであり、入熱15kJ/cmのCO2溶接を行った。試験の結果、予熱温度175℃でルート割れ率が0であれば合格と評価した。また、板厚が25mm未満の実施例2、4、8、11の鋼板については、溶接性は同一成分の実施例3、5、7、12と同じであると考えられるため、y型溶接割れ試験を省略した。
耐遅れ破壊特性の評価のために、それぞれの鋼板の「限界拡散性水素量Hc」および「環境から侵入する拡散性水素量HE」を測定した。Hc/HEが3よりも大きい場合に、耐遅れ破壊特性が良好であると評価した。
尚、Ac3変態点は、富士電波工機製Formastor-FIIを用いて、2.5℃/分での昇温速度条件で熱膨張測定により測定した。
Claims (4)
- 質量%で、
C:0.18%以上、0.23%以下、
Si:0.1%以上、0.5%以下、
Mn:1.0%以上、2.0%以下、
P:0.020%以下、
S:0.010%以下、
Cu:0.5%超、3.0%以下、
Ni:0.25%以上、2.0%以下、
Nb:0.003%以上、0.10%以下、
Al:0.05%以上、0.15%以下、
B:0.0003%以上、0.0030%以下、
N:0.006%以下
を含み、残部がFeおよび不可避的不純物からなり、かつ[C]、[Si]、[Mn]、[Cu]、[Ni]、[Cr]、[Mo]、[V]、[B]を、それぞれ、C、Si、Mn、Cu、Ni、Cr、Mo、V、Bの濃度(質量%)とした場合に、Pcm=[C]+[Si]/30+[Mn]/20+[Cu]/20+[Ni]/60+[Cr]/20+[Mo]/15+[V]/10+5[B]により算出される溶接割れ感受性指標Pcmが0.39%以下であることを満たす成分組成を有し;
Ac3変態点が850℃以下であり、マルテンサイト組織分率が90%以上であり、降伏強度が1300MPa以上であり、引張強度が1400MPa以上かつ1650MPa以下であり、さらに、引張強度と、試料片断面の1mm2当りの平均結晶粒数mを用いて、Nγ=-3+log2mにより算出される旧オーステナイト結晶粒度番号Nγとが、前記引張り強度を[TS](MPa)とした場合に、前記引張強度が1550MPa未満では、Nγ≧([TS]-1400)×0.006+7.0を満たし、前記引張強度が1550MPa以上では、Nγ≧([TS]-1550)×0.01+7.9を満たす;
ことを特徴とする高強度厚鋼板。 - 質量%で、さらに、
Cr:0.05%以上、1.5%以下、
Mo:0.03%以上、0.5%以下、
V:0.01%以上、0.10%以下
のうちの1種以上を含むことを特徴とする、請求項1に記載の高強度厚鋼板。 - 板厚が4.5mm以上25mm以下であることを特徴とする、請求項1または請求項2に記載の高強度厚鋼板。
- 請求項1または請求項2に記載の成分組成を有する鋼片または鋳片を1100℃以上に加熱し;
板厚が4.5mm以上、25mm以下の鋼板となるように、930℃以下、860℃以上の温度範囲での累積圧下率が30%以上、65%以下であり、860℃以上で圧延を終了する熱間圧延を行い;
冷却後、前記鋼板をAc3変態点+20℃以上、かつ870℃以下の温度に再加熱し;
その後、600℃から300℃までの前記鋼板の板厚中心部における平均冷却速度が20℃/sec以上となる冷却条件で200℃以下まで加速冷却を行い;
さらにその後、200℃以上、300℃以下の温度範囲で焼戻し熱処理を行う;
ことを特徴とする高強度厚鋼板の製造方法。
Priority Applications (6)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BRPI0905378-6A BRPI0905378B1 (pt) | 2008-11-11 | 2009-10-13 | High resistance steel sheet |
JP2010506755A JP4542624B2 (ja) | 2008-11-11 | 2009-10-13 | 高強度厚鋼板およびその製造方法 |
CN2009801007965A CN101835917B (zh) | 2008-11-11 | 2009-10-13 | 高强度厚钢板及其制造方法 |
BR122017004300-5A BR122017004300B1 (pt) | 2008-11-11 | 2009-10-13 | Method of production of a high resistance steel sheet |
US12/734,414 US8500924B2 (en) | 2008-11-11 | 2009-10-13 | High-strength steel plate and producing method therefor |
EP09822871A EP2290116B1 (en) | 2008-11-11 | 2009-10-13 | Thick steel sheet having high strength and method for producing same |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2008-288859 | 2008-11-11 | ||
JP2008288859 | 2008-11-11 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2010055609A1 true WO2010055609A1 (ja) | 2010-05-20 |
Family
ID=42169756
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2009/005315 WO2010055609A1 (ja) | 2008-11-11 | 2009-10-13 | 高強度厚鋼板およびその製造方法 |
Country Status (9)
Country | Link |
---|---|
US (1) | US8500924B2 (ja) |
EP (1) | EP2290116B1 (ja) |
JP (1) | JP4542624B2 (ja) |
KR (1) | KR101028613B1 (ja) |
CN (1) | CN101835917B (ja) |
AU (1) | AU2009292610B8 (ja) |
BR (2) | BRPI0905378B1 (ja) |
TW (1) | TWI344995B (ja) |
WO (1) | WO2010055609A1 (ja) |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140076470A1 (en) * | 2011-05-12 | 2014-03-20 | Kangying Zhu | Method for the production of very high strength martensitic steel and sheet or part thus obtained |
JP2016148098A (ja) * | 2015-02-13 | 2016-08-18 | 株式会社神戸製鋼所 | 降伏比と加工性に優れた超高強度鋼板 |
CN106164319A (zh) * | 2013-12-11 | 2016-11-23 | 安赛乐米塔尔公司 | 具有耐延迟断裂性的马氏体钢及制造方法 |
US9963756B2 (en) * | 2011-05-12 | 2018-05-08 | ArcelorMittal Investigación y Desarrollo, S.L. | Method for production of martensitic steel having a very high yield point and sheet or part thus obtained |
JP2019002078A (ja) * | 2018-09-10 | 2019-01-10 | 株式会社神戸製鋼所 | 降伏比と加工性に優れた超高強度鋼板 |
JP2021509147A (ja) * | 2017-12-26 | 2021-03-18 | ポスコPosco | 超高強度熱延鋼板、鋼管、部材、及びその製造方法 |
Families Citing this family (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US9938599B2 (en) | 2011-03-29 | 2018-04-10 | Jfe Steel Corporation | Abrasion resistant steel plate or steel sheet excellent in resistance to stress corrosion cracking and method for manufacturing the same |
CN102808132B (zh) * | 2011-06-01 | 2014-03-12 | 中国北车集团大同电力机车有限责任公司 | 牵引座铸造及处理工艺 |
AU2013319622B2 (en) | 2012-09-19 | 2016-10-13 | Jfe Steel Corporation | Wear-resistant steel plate having excellent low-temperature toughness and corrosion wear resistance |
CA2899570C (en) * | 2013-03-15 | 2019-04-30 | Jfe Steel Corporation | Thick, tough, high tensile strength steel plate and production method therefor |
JP6235221B2 (ja) | 2013-03-28 | 2017-11-22 | Jfeスチール株式会社 | 低温靭性および耐水素脆性を有する耐磨耗厚鋼板およびその製造方法 |
JP2016153524A (ja) * | 2015-02-13 | 2016-08-25 | 株式会社神戸製鋼所 | 切断端部での耐遅れ破壊特性に優れた超高強度鋼板 |
CN105088075A (zh) * | 2015-09-07 | 2015-11-25 | 江苏天舜金属材料集团有限公司 | 一种高强钢筋及其控制混凝土结构构件裂缝宽度的方法 |
CN106756567B (zh) * | 2017-02-08 | 2018-06-15 | 北京科技大学 | 一种强塑积≥40GPa·%的热轧低密度钢的制备方法 |
KR102031443B1 (ko) * | 2017-12-22 | 2019-11-08 | 주식회사 포스코 | 우수한 경도와 충격인성을 갖는 내마모강 및 그 제조방법 |
WO2020162983A1 (en) * | 2019-02-08 | 2020-08-13 | Nucor Corporation | Ultra-high strength weathering steel and high friction rolling of the same |
BR112022005206A2 (pt) * | 2019-09-19 | 2022-06-14 | Nucor Corp | Aço patinável de ultra-alta resistência para aplicações de estampagem a quente |
Citations (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6480903A (en) | 1987-09-22 | 1989-03-27 | Nikon Corp | Infrared optical element |
JPH01149921A (ja) | 1987-12-04 | 1989-06-13 | Kawasaki Steel Corp | 耐遅れ割れ性の優れた直接焼入れ型高強度鋼の製造方法 |
JPH01229075A (ja) | 1988-03-08 | 1989-09-12 | Whittaker Corp | 金属基材に耐腐食性が向上した塗料を塗布する方法 |
JPH06248386A (ja) * | 1993-02-26 | 1994-09-06 | Sumitomo Metal Ind Ltd | 耐遅れ破壊性に優れた機械構造用鋼 |
JPH0790488A (ja) | 1993-09-27 | 1995-04-04 | Kobe Steel Ltd | 耐水素脆化特性の優れた超高強度冷延鋼板とその製造方法 |
JPH08311601A (ja) | 1995-05-19 | 1996-11-26 | Kobe Steel Ltd | 耐遅れ破壊特性にすぐれる超高強度鋼板及びその製造方法 |
JPH09263876A (ja) | 1996-03-29 | 1997-10-07 | Nippon Steel Corp | 遅れ破壊特性の優れた高強度機械構造用鋼およびその製造方法 |
JPH11229075A (ja) | 1998-02-18 | 1999-08-24 | Sumitomo Metal Ind Ltd | 耐遅れ破壊特性に優れる高強度鋼およびその製造方法 |
JP2001107139A (ja) | 1999-10-08 | 2001-04-17 | Kawasaki Steel Corp | 耐遅れ破壊特性および海浜耐候性に優れるボルト部品の製造方法 |
JP2005097725A (ja) * | 2003-09-05 | 2005-04-14 | Nippon Steel Corp | 耐水素脆化特性に優れたホットプレス用鋼板、自動車用部材及びその製造方法 |
JP2007302974A (ja) * | 2006-05-15 | 2007-11-22 | Jfe Steel Kk | 耐遅れ破壊特性に優れた高強度厚鋼板およびその製造方法 |
JP2007308743A (ja) * | 2006-05-17 | 2007-11-29 | Nissan Motor Co Ltd | 抵抗溶接用高張力鋼板及びその接合方法 |
JP2008288859A (ja) | 2007-05-17 | 2008-11-27 | Olympus Corp | 高度な色再現が可能な映像表示システム |
Family Cites Families (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH0670250B2 (ja) * | 1988-11-19 | 1994-09-07 | 住友金属工業株式会社 | 靭性の優れた調質型高張力鋼板の製造方法 |
JPH02236223A (ja) | 1989-03-07 | 1990-09-19 | Nippon Steel Corp | 遅れ破壊特性の優れた高強度鋼の製造法 |
JP3543619B2 (ja) | 1997-06-26 | 2004-07-14 | 住友金属工業株式会社 | 高靱性耐摩耗鋼およびその製造方法 |
JPH1180903A (ja) | 1997-09-08 | 1999-03-26 | Nkk Corp | 遅れ破壊特性に優れた高強度鋼部材およびその製造方法 |
US7048810B2 (en) | 2001-10-22 | 2006-05-23 | Exxonmobil Upstream Research Company | Method of manufacturing hot formed high strength steel |
JP3968011B2 (ja) | 2002-05-27 | 2007-08-29 | 新日本製鐵株式会社 | 低温靱性および溶接熱影響部靱性に優れた高強度鋼とその製造方法および高強度鋼管の製造方法 |
CN100447278C (zh) * | 2005-01-11 | 2008-12-31 | 宝山钢铁股份有限公司 | 一种可大线能量焊接的厚钢板及制造方法 |
JP5124988B2 (ja) | 2005-05-30 | 2013-01-23 | Jfeスチール株式会社 | 耐遅れ破壊特性に優れた引張強度900MPa以上の高張力鋼板およびその製造方法 |
CN100412223C (zh) * | 2006-07-20 | 2008-08-20 | 武汉钢铁(集团)公司 | 具有优良耐蚀性和抗疲劳性的超高强度钢及其制造方法 |
JP5277648B2 (ja) | 2007-01-31 | 2013-08-28 | Jfeスチール株式会社 | 耐遅れ破壊特性に優れた高張力鋼板並びにその製造方法 |
-
2009
- 2009-10-13 BR BRPI0905378-6A patent/BRPI0905378B1/pt active IP Right Grant
- 2009-10-13 CN CN2009801007965A patent/CN101835917B/zh active Active
- 2009-10-13 KR KR1020107009507A patent/KR101028613B1/ko active IP Right Grant
- 2009-10-13 BR BR122017004300-5A patent/BR122017004300B1/pt active IP Right Grant
- 2009-10-13 US US12/734,414 patent/US8500924B2/en active Active
- 2009-10-13 WO PCT/JP2009/005315 patent/WO2010055609A1/ja active Application Filing
- 2009-10-13 AU AU2009292610A patent/AU2009292610B8/en active Active
- 2009-10-13 EP EP09822871A patent/EP2290116B1/en active Active
- 2009-10-13 JP JP2010506755A patent/JP4542624B2/ja active Active
- 2009-10-14 TW TW098134758A patent/TWI344995B/zh active
Patent Citations (13)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS6480903A (en) | 1987-09-22 | 1989-03-27 | Nikon Corp | Infrared optical element |
JPH01149921A (ja) | 1987-12-04 | 1989-06-13 | Kawasaki Steel Corp | 耐遅れ割れ性の優れた直接焼入れ型高強度鋼の製造方法 |
JPH01229075A (ja) | 1988-03-08 | 1989-09-12 | Whittaker Corp | 金属基材に耐腐食性が向上した塗料を塗布する方法 |
JPH06248386A (ja) * | 1993-02-26 | 1994-09-06 | Sumitomo Metal Ind Ltd | 耐遅れ破壊性に優れた機械構造用鋼 |
JPH0790488A (ja) | 1993-09-27 | 1995-04-04 | Kobe Steel Ltd | 耐水素脆化特性の優れた超高強度冷延鋼板とその製造方法 |
JPH08311601A (ja) | 1995-05-19 | 1996-11-26 | Kobe Steel Ltd | 耐遅れ破壊特性にすぐれる超高強度鋼板及びその製造方法 |
JPH09263876A (ja) | 1996-03-29 | 1997-10-07 | Nippon Steel Corp | 遅れ破壊特性の優れた高強度機械構造用鋼およびその製造方法 |
JPH11229075A (ja) | 1998-02-18 | 1999-08-24 | Sumitomo Metal Ind Ltd | 耐遅れ破壊特性に優れる高強度鋼およびその製造方法 |
JP2001107139A (ja) | 1999-10-08 | 2001-04-17 | Kawasaki Steel Corp | 耐遅れ破壊特性および海浜耐候性に優れるボルト部品の製造方法 |
JP2005097725A (ja) * | 2003-09-05 | 2005-04-14 | Nippon Steel Corp | 耐水素脆化特性に優れたホットプレス用鋼板、自動車用部材及びその製造方法 |
JP2007302974A (ja) * | 2006-05-15 | 2007-11-22 | Jfe Steel Kk | 耐遅れ破壊特性に優れた高強度厚鋼板およびその製造方法 |
JP2007308743A (ja) * | 2006-05-17 | 2007-11-29 | Nissan Motor Co Ltd | 抵抗溶接用高張力鋼板及びその接合方法 |
JP2008288859A (ja) | 2007-05-17 | 2008-11-27 | Olympus Corp | 高度な色再現が可能な映像表示システム |
Non-Patent Citations (2)
Title |
---|
See also references of EP2290116A4 |
TETSU-TO-HAGANÉ, vol. 83, 1997, pages 454 |
Cited By (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20140076470A1 (en) * | 2011-05-12 | 2014-03-20 | Kangying Zhu | Method for the production of very high strength martensitic steel and sheet or part thus obtained |
US9963756B2 (en) * | 2011-05-12 | 2018-05-08 | ArcelorMittal Investigación y Desarrollo, S.L. | Method for production of martensitic steel having a very high yield point and sheet or part thus obtained |
US10337090B2 (en) * | 2011-05-12 | 2019-07-02 | Arcelormittal Investigaciòn Y Desarrollo, S.L. | Method for the production of very high strength martensitic steel and sheet or part thus obtained |
US10895003B2 (en) | 2011-05-12 | 2021-01-19 | Arcelormittal | Very high strength martensitic steel or part and method of fabrication |
CN106164319A (zh) * | 2013-12-11 | 2016-11-23 | 安赛乐米塔尔公司 | 具有耐延迟断裂性的马氏体钢及制造方法 |
CN106164319B (zh) * | 2013-12-11 | 2021-11-05 | 安赛乐米塔尔公司 | 具有耐延迟断裂性的马氏体钢及制造方法 |
JP2016148098A (ja) * | 2015-02-13 | 2016-08-18 | 株式会社神戸製鋼所 | 降伏比と加工性に優れた超高強度鋼板 |
JP2021509147A (ja) * | 2017-12-26 | 2021-03-18 | ポスコPosco | 超高強度熱延鋼板、鋼管、部材、及びその製造方法 |
JP7186229B2 (ja) | 2017-12-26 | 2022-12-08 | ポスコ | 超高強度熱延鋼板、鋼管、部材、及びその製造方法 |
US11939639B2 (en) | 2017-12-26 | 2024-03-26 | Posco Co., Ltd | Ultra-high-strength hot-rolled steel sheet, steel pipe, member, and manufacturing methods therefor |
JP2019002078A (ja) * | 2018-09-10 | 2019-01-10 | 株式会社神戸製鋼所 | 降伏比と加工性に優れた超高強度鋼板 |
Also Published As
Publication number | Publication date |
---|---|
EP2290116A4 (en) | 2011-05-25 |
BR122017004300B1 (pt) | 2017-11-14 |
AU2009292610A1 (en) | 2010-05-27 |
KR101028613B1 (ko) | 2011-04-11 |
BRPI0905378B1 (pt) | 2017-06-27 |
CN101835917A (zh) | 2010-09-15 |
TW201022453A (en) | 2010-06-16 |
US20110253271A1 (en) | 2011-10-20 |
JP4542624B2 (ja) | 2010-09-15 |
EP2290116A1 (en) | 2011-03-02 |
AU2009292610B2 (en) | 2011-02-10 |
AU2009292610B8 (en) | 2011-03-31 |
KR20100075982A (ko) | 2010-07-05 |
CN101835917B (zh) | 2012-06-20 |
US8500924B2 (en) | 2013-08-06 |
TWI344995B (en) | 2011-07-11 |
JPWO2010055609A1 (ja) | 2012-04-12 |
EP2290116B1 (en) | 2012-06-27 |
BRPI0905378A2 (pt) | 2015-06-30 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP4538094B2 (ja) | 高強度厚鋼板およびその製造方法 | |
JP4542624B2 (ja) | 高強度厚鋼板およびその製造方法 | |
KR100918321B1 (ko) | 내지연파괴특성이 우수한 고장력 강재 | |
JP4897125B2 (ja) | 高強度鋼板とその製造方法 | |
JP5846311B2 (ja) | 溶接熱影響部ctod特性に優れた厚肉高張力鋼およびその製造方法 | |
WO2012133911A1 (ja) | 耐応力腐食割れ性に優れた耐磨耗鋼板およびその製造方法 | |
JP5182642B2 (ja) | 耐遅れ破壊特性および溶接性に優れる高強度厚鋼板およびその製造方法 | |
JP5439973B2 (ja) | 優れた生産性と溶接性を兼ね備えた、pwht後の落重特性に優れた高強度厚鋼板およびその製造方法 | |
JP5037744B2 (ja) | 高強度鋼板及びその製造方法 | |
KR20150088320A (ko) | 인장 강도 540 ㎫ 이상의 고강도 라인 파이프용 열연 강판 | |
JP2010121191A (ja) | 耐遅れ破壊特性および溶接性に優れる高強度厚鋼板およびその製造方法 | |
JP4434029B2 (ja) | 溶接性と継手靱性に優れた高張力鋼材 | |
JP6536331B2 (ja) | 高強度鋼板及びその製造方法 | |
JP4830318B2 (ja) | 表面性状に優れた非調質高張力鋼の製造方法 | |
JP4967373B2 (ja) | 非調質高張力鋼板およびその製造方法 | |
JP2006193817A (ja) | 靱性、溶接性および生産性に優れた鋼板およびその製造方法 | |
KR20150049660A (ko) | 고강도 강판 제조 방법 및 이를 이용한 고강도 강관 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
WWE | Wipo information: entry into national phase |
Ref document number: 200980100796.5 Country of ref document: CN |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2010506755 Country of ref document: JP |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2009292610 Country of ref document: AU |
|
WWE | Wipo information: entry into national phase |
Ref document number: 12734414 Country of ref document: US |
|
ENP | Entry into the national phase |
Ref document number: 20107009507 Country of ref document: KR Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 2009822871 Country of ref document: EP |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 09822871 Country of ref document: EP Kind code of ref document: A1 |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
ENP | Entry into the national phase |
Ref document number: PI0905378 Country of ref document: BR Kind code of ref document: A2 Effective date: 20100430 |