WO2019077777A1 - 高強度鋼板およびその製造方法 - Google Patents
高強度鋼板およびその製造方法 Download PDFInfo
- Publication number
- WO2019077777A1 WO2019077777A1 PCT/JP2018/013074 JP2018013074W WO2019077777A1 WO 2019077777 A1 WO2019077777 A1 WO 2019077777A1 JP 2018013074 W JP2018013074 W JP 2018013074W WO 2019077777 A1 WO2019077777 A1 WO 2019077777A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- less
- martensite
- steel sheet
- strength steel
- strength
- Prior art date
Links
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
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B32—LAYERED PRODUCTS
- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
- B32B15/013—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of an iron alloy or steel, another layer being formed of a metal other than iron or aluminium
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/005—Heat treatment of ferrous alloys containing Mn
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/008—Heat treatment of ferrous alloys containing Si
-
- 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
- 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
- C21D8/0236—Cold 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
-
- 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
- C21D8/0268—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment between cold rolling steps
-
- 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
- C21D8/0273—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
- 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
- C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
-
- 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
- C22C38/06—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
- C22C38/10—Ferrous alloys, e.g. steel alloys containing cobalt
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- 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
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
-
- 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
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium 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
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- 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
- C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/02—Pretreatment of the material to be coated, e.g. for coating on selected surface areas
- C23C2/022—Pretreatment of the material to be coated, e.g. for coating on selected surface areas by heating
- C23C2/0224—Two or more thermal pretreatments
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/12—Aluminium or alloys based thereon
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/26—After-treatment
- C23C2/28—Thermal after-treatment, e.g. treatment in oil bath
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
Definitions
- the present invention relates to a high strength steel plate mainly used as a part of a car and a method of manufacturing the same. Specifically, a high strength steel sheet having a high strength of 550 MPa or more and a characteristic of excellent weld fatigue properties and a method of manufacturing the same.
- a high strength steel sheet having a yield strength of 550 MPa or more usually contains a large amount of alloying elements necessary for high strength. Therefore, it is necessary to take measures to suppress the decrease in weldability due to these alloying elements.
- Patent Document 1 discloses a high strength cold rolled steel sheet excellent in weldability and processability and a method of manufacturing the same.
- Patent Document 2 discloses a high-strength galvanized steel sheet excellent in bendability and weldability having a tensile strength of 980 MPa or more and a method of manufacturing the same.
- Patent Document 3 discloses a high-strength hot-dip galvanized steel sheet excellent in workability, weldability, and fatigue characteristics, which has a tensile strength of 980 MPa or more, and a method of manufacturing the same.
- Patent Document 4 discloses a high strength steel plate excellent in weldability and stretch flangeability having a tensile strength of 780 MPa or more and a method of manufacturing the same.
- the toughness of the heat-affected zone in the vicinity of the weld-solidified portion which is called a nugget in the case of resistance spot welding, is insufficient, and the fatigue strength of the welded portion is reduced. If the reduction in weld fatigue strength can be suppressed, the collision strength of the entire vehicle can be sufficiently maintained.
- this weld portion fatigue strength is not intended directly.
- Patent Document 1 The high-strength cold-rolled steel sheet described in Patent Document 1 is applied to a welded portion and a collision absorbing member. However, after deformation of the welded portion, the fatigue strength of the welded portion is reduced to cause fracture, leaving a problem in practical use.
- the high strength hot-dip galvanized steel sheet described in Patent Document 2 is effective for conventional static tensile shear. However, it is more preferable if the reduction in fatigue strength of the welded portion after deformation of the welded portion can be suppressed.
- the high strength hot-dip galvanized steel sheet described in Patent Document 3 is effective for conventional static tensile shear. However, it is more preferable if the reduction in fatigue strength of the welded portion after deformation of the welded portion can be suppressed.
- the high strength steel plate described in Patent Document 4 is effective for conventional static tensile shear. However, it is more preferable if the reduction in fatigue strength of the welded portion after deformation of the welded portion can be suppressed.
- the present invention advantageously solves the problems of the above-mentioned prior art, and an object of the present invention is to provide a high strength steel plate having a yield strength of 550 MPa or more excellent in weld fatigue strength and a method of manufacturing the same.
- Cracks generated by deforming a spot welded portion contain 40 to 75% martensite phase by volume fraction in the structure in the rolling direction, and the average grain size of martensite grains in the entire martensite phase It can suppress by controlling to the steel structure whose sum total volume ratio of 1/4 or more and 1 or less of martensite grain of a diameter of a ferrite grain of a disjunction diameter is 60% or more.
- the present invention provides the following.
- the above-mentioned component composition further contains at least 1% or less in total of any one or more of Mo: 0.03 to 0.50%, Cr: 0.1 to 1.0% by mass%.
- the above-mentioned component composition is any of Cu, Ni, Sn, As, Sb, Ca, Mg, Pb, Co, Ta, W, REM, Zn, V, Sr, Cs and Hf in mass%.
- the steel slab After hot rolling a steel slab having the composition described in any one of [1] to [3], the steel slab is cooled at an average cooling rate of 10 to 30 ° C./s, and a coiling temperature of 470 to A hot rolling step of winding at 700 ° C., a cold rolling step of cold rolling the hot rolled steel sheet obtained in the hot rolling step, and a cold rolled steel plate obtained in the cold rolling step at 750 to 900 ° C. Heat to an annealing temperature range of 30, annealing time: 30 to 200 seconds, average cooling rate to 600 ° C .: 10 to 40 ° C./s, bending at a radius of 1500 mm or less when cooling to 600 ° C. A method of manufacturing a high-strength steel sheet, comprising: an annealing step of cooling back on the condition of a cooling stop temperature of 400 to 600 ° C. and holding the temperature at the cooling stop temperature for 2 to 200 seconds.
- the steel plate of the present invention can provide a high-strength hot-dip galvanized steel sheet excellent in the fatigue strength of a resistance spot welded portion with a yield strength of 550 MPa or more.
- % representing the content of the component means mass%.
- C 0.05 to 0.15% C is an element necessary to form martensite and to increase the strength.
- the C content is made 0.05% or more.
- it is 0.06% or more, More preferably, it is 0.07% or more.
- the result of the cross tension test representing the weld portion fatigue strength can be 300 N or more.
- the C content exceeds 0.15%, a large amount of cementite is formed in the heat-affected zone to lower the toughness of the portion which has become martensite in the heat-affected zone, and the weld zone fatigue strength decreases.
- the C content exceeds 0.15%, the sum total volume ratio of the martensitic grain whose average of the ratio mentioned later is 1/4 or more and 1 or less may not become a desired range. Therefore, the C content is made 0.15% or less. Preferably it is 0.13% or less, More preferably, it is 0.11% or less. In particular, if the C content is 0.11% or less, the result of the cross tension test representing the weld portion fatigue strength can be 300 N or more.
- Si 0.01 to 1.80% Si is an element which has the effect
- Si needs to be contained 0.01% or more.
- it is 0.10% or more, more preferably 0.35% or more.
- the result of the cross tension test representing the weld portion fatigue strength can be 300 N or more. More preferably, it is 0.51% or more.
- the upper limit is 1.80%.
- it is 1.40% or less. More preferably, it is 1.20% or less. Most preferably, it is 1.00% or less. If the Si content is 1.00% or less, the result of the cross tension test representing the weld portion fatigue strength can be 300 N or more.
- Mn 1.8 to 3.2%
- Mn is an element having the effect of enhancing the hardness of the steel sheet by solid solution strengthening. It is an element that increases the strength of the material by generating martensite by suppressing ferrite transformation and bainite transformation.
- Mn needs to contain 1.8% or more. Preferably it is 2.1% or more, more preferably 2.2% or more. If the Mn content is 2.2% or more, the result of the cross tension test representing the weld portion fatigue strength can be 300 N or more.
- the upper limit of Mn is made 3.2%.
- Mn content is increased, cementite is formed by tempering and the toughness of the heat-affected zone is lowered, and the fatigue strength of the weld zone is lowered, so the upper limit of Mn is made 3.2%.
- Mn is 3.1% or less, more preferably 2.9% or less. If the Mn content is 2.9% or less, the result of the cross tension test representing the weld portion fatigue strength can be 300 N or more.
- the upper limit is set to 0.05% or less. Preferably it is 0.03% or less, More preferably, it is 0.02% or less.
- the lower limit is not particularly limited, and the lower the P content, the better, but from the viewpoint of manufacturability, 0.0001% or more is preferable.
- S 0.020% or less S combines with Mn to form coarse MnS and reduces toughness. For this reason, it is preferable to reduce the S content. It may be 0.020% or less. Preferably it is 0.010% or less, More preferably, it is 0.002% or less. The lower limit is not particularly limited, and the smaller the S content, the better, but from the viewpoint of manufacturability, 0.0001% or more is preferable.
- Al 0.01 to 2.0% Deoxidation is important because the presence of large amounts of oxides in the steel reduces toughness.
- Al may suppress precipitation of cementite.
- it is necessary to contain 0.01% or more.
- it is 0.02% or more, more preferably 0.03% or more.
- the oxides and nitrides are aggregated and coarsened to lower the toughness, so the upper limit is made 2.0% or less.
- it is 1.5% or less, more preferably 0.1% or less.
- N 0.010% or less
- N is a harmful element in the present invention, and it is preferable to reduce it as much as possible.
- N combines with Ti to form TiN, but when the N content exceeds 0.010%, the toughness of the weld is deteriorated due to the increase in the amount of TiN formed. Therefore, the N content is made 0.010% or less. Preferably it is 0.008% or less, more preferably 0.006% or less.
- B at least one of 0.0001 to 0.005%, Ti: 0.005 to 0.04%, Nb: 0.005 to 0.06% or less.
- B 0.0001 to 0.005%
- B is an element necessary for strengthening grain boundaries to improve toughness. In order to obtain sufficient effects, the B content needs to be 0.0001% or more. Preferably it is 0.001% or more. On the other hand, if it exceeds 0.005%, B forms Fe 23 (CB) 6 to deteriorate the toughness. Therefore, B should be 0.005% or less. Preferably it is 0.004% or less.
- Ti 0.005 to 0.04% Ti combines with N to form nitrides, thereby suppressing the formation of BN and eliciting the effect of B, while forming TiN to refine the crystal grains and improve the toughness.
- the content of Ti needs to be 0.005% or more. Preferably, it is 0.010% or more.
- the Ti content is 0.04% or less. Preferably it is 0.03% or less.
- Nb 0.005 to 0.06%
- Nb is an element that further improves the effects of the present invention.
- Nb prevents the refinement of martensite and the coarsening of crystal grains in the heat-affected zone to improve the toughness of the heat-affected zone.
- the Nb content to obtain this effect is 0.005% or more. Preferably, it is 0.010% or more.
- the Nb content exceeds 0.06%, the total volume fraction of martensite grains having an average of the ratio described later of 1/4 or more and 1 or less does not fall within the desired range, and Nb carbides are precipitated. And the toughness deteriorates in reverse. Therefore, the Nb content is limited to 0.06% or less. Preferably it is 0.04% or less. If the Nb content is 0.04% or less, it is possible to make the result of the cross tension test representing the weld portion fatigue strength 300 N or more. In addition, the strength of the joint can be improved by suppressing liquid metal embrittlement of the welded joint.
- Ti and Nb may include at least one of these. If the content of any of the elements is in the above range, even if other elements are contained below the lower limit, the other elements contained below this lower limit are included as unavoidable impurities.
- the above-mentioned component composition can contain any one or more of Mo: 0.03 to 0.50% and Cr: 0.1 to 1.0% in total as 1% or less as optional components.
- Mo 0.03 to 0.50% Mo promotes nucleation of austenite and refines martensite. In order to obtain this effect, the content of Mo needs to be 0.03% or more. Preferably it is 0.04% or more. On the other hand, when Mo is grain boundary segregated, grain growth of the ferrite stops, so the ferrite becomes too fine. In order to suppress this, the content of Mo is 0.50% or less. Preferably, it is 0.30% or less.
- Cr 0.1 to 1.0% Cr is an element having an effect of suppressing temper embrittlement. Therefore, the effect of the present invention is further enhanced by containing Cr.
- the Cr content is made 0.1% or more. Preferably it is 0.2% or more. However, the content exceeding 1.0% leads to the formation of Cr carbides and causes the toughness deterioration of the heat affected zone. Therefore, the Cr content is 1.0% or less. Preferably it is 0.5% or less.
- the total amount of Cr and Mo needs to be 1% or less because the toughness of the welded portion is reduced.
- the component composition of the high strength steel plate of the present invention is any of Cu, Ni, Sn, As, Sb, Ca, Mg, Pb, Co, Ta, W, REM, Zn, V, Sr, Cs and Hf as optional components. You may contain 0.5% or less in total of 1 or more types. Preferably it is 0.1% or less, more preferably 0.03% or less. Moreover, the components other than the above are Fe and an unavoidable impurity.
- an effect of the present invention is not impaired even if it contains an element having a lower limit value for an optional component below the lower limit value, an optional element less than the lower limit value is included as an unavoidable impurity.
- volume fraction of martensite phase in observation of plate thickness section in rolling direction 40 to 75%
- the martensitic phase is a hard phase, and has the effect of increasing the strength of the steel sheet by transformation structure strengthening.
- the volume fraction of the martensite phase is 40% or more. Preferably it is 45% or more, more preferably 50% or more.
- the volume fraction of the martensite phase is set to 75% or less. Preferably it is 70% or less, More preferably, it is 65% or less, More preferably, it is 59% or less.
- the above volume fraction means the total volume fraction of as-quenched martensite (non-tempered martensite) and tempered martensite.
- the martensitic phase contains a ferrite phase.
- the volume fraction of the ferrite phase is not particularly limited, but is preferably 25 to 60%.
- the lower limit is more preferably 30% or more, still more preferably 35% or more.
- the upper limit is more preferably 55% or less, still more preferably 50% or less.
- bainite pearlite and retained austenite may be contained in the steel structure of the high strength steel plate of the present invention. A total of 10% or less of these other phases is acceptable.
- the total volume fraction of martensite grains having an average ratio of grain sizes of martensite grains and adjacent ferrite grains of not less than 1/4 and not more than 1 is made 60% or more.
- the upper limit is not particularly limited, but is preferably 90% or less, more preferably 85% or less, and still more preferably 80% or less.
- the ferrite grain which adjoins a martensitic grain means the ferrite grain which contact
- the average of the ratio of the grain size of the martensite grain and the adjacent ferrite grain means the grain size ratio of each ferrite grain to the martensite grain calculated in the observation of the plate thickness section and the average of them. . For example, when there are three ferrite grains adjacent to martensite grains, the grain size ratio of martensite grains to each ferrite grain is calculated, and then the three grain size ratios obtained are averaged to obtain marten The average of the ratio of the grain size of the site grain and the adjacent ferrite grain is obtained.
- the total volume fraction of martensite grains having an average of the ratio of grain sizes of martensite grains and adjacent ferrite grains in the martensite phase is 1/4 or more and 1 or less may be within the above range.
- the average particle size of the particles and the average particle size of the ferrite particles are not particularly limited.
- the average grain size of martensite grains is preferably in the range of 1 to 8 ⁇ m, and the lower limit is preferably 2 ⁇ m or more, more preferably 3 ⁇ m or more.
- the upper limit is preferably 7 ⁇ m or less, more preferably 5 ⁇ m or less.
- the ferrite particles are preferably in the range of 3 to 15 ⁇ m, and the lower limit is preferably 4 ⁇ m or more, more preferably 5 ⁇ m or more.
- the upper limit is preferably 10 ⁇ m or less, more preferably 9 ⁇ m or less.
- the high strength steel plate of the present invention has a yield strength YP of 550 MPa or more. Preferably it is 560 MPa or more, More preferably, it is 570 MPa or more.
- the upper limit of YP is preferably 800 MPa or less, more preferably 750 MPa or less, and still more preferably 700 MPa or less, in consideration of balance with other properties, ease of obtaining a desired structure, and the like.
- the tensile strength (TS), which is another tensile property, is preferably 950 MPa or more, more preferably 980 MPa or more, and still more preferably 1000 MPa or more.
- the upper limit of the tensile strength is preferably 1200 MPa or less, more preferably 1150 MPa or less, still more preferably 1100 MPa or less, in consideration of balance with other properties, easiness of obtaining a desired structure, and the like.
- the other elongation property, butt elongation (El), is preferably 14.0% or more, more preferably 14.5% or more, and still more preferably 15.0% or more.
- El is preferably 20.0% or less, more preferably 19.0% or less, and further preferably 18.0% or less.
- the high strength steel plate of the present invention has excellent weld fatigue strength.
- the cross tensile force measured by the method described in the examples is 250 N or more. More preferably, it is 275 N or more, more preferably 300 N or more.
- the upper limit is preferably 500 N or less, more preferably 450 N or less, and still more preferably 400 N or less, in consideration of balance with other properties, ease of obtaining a desired tissue, and the like.
- the high strength steel plate of the present invention may be a high strength steel plate having a plating layer on the surface.
- a plating layer a hot-dip galvanization layer, an electrogalvanized layer, a hot-dip aluminum plating layer etc. can be illustrated as a plating layer.
- the plating layer may be an alloyed hot-dip galvanized layer formed by performing an alloying treatment after hot-dip galvanizing.
- the manufacturing method of the high strength steel plate of the present invention has a hot rolling process, a cold rolling process, and an annealing process.
- the production method of the present invention further includes a plating step. Each of these steps will be described below.
- the hot rolling step is a step of cooling a steel slab having the above-mentioned component composition after hot rolling and then cooling it at an average cooling rate of 10 to 30 ° C./s and winding it at a winding temperature of 470 to 700 ° C. is there.
- the melting method of the steel material is not particularly limited, and a known melting method such as a converter or an electric furnace can be adopted. Further, after melting, it is preferable to use a steel material by a continuous casting method because of problems such as segregation and the like, but a slab may be formed by a known casting method such as ingot-mass rolling method or thin slab continuous casting method. In addition, in hot rolling of the slab after casting, rolling may be performed after reheating the slab in a heating furnace, or when maintaining a temperature equal to or higher than a predetermined temperature, direct delivery rolling without heating the slab You may
- the above obtained steel material is subjected to hot rolling composed of rough rolling and finish rolling, but in the present invention, it is necessary to melt carbides in the steel material before rough rolling.
- the slab is heated, it is preferable to heat it to 1100 ° C. or higher in order to melt carbides or prevent an increase in rolling load.
- it is preferable to set the heating temperature of the slab to 1300 ° C. or less.
- the finish rolling end temperature is preferably in the range of 850 to 1000.degree.
- Average cooling rate after finish rolling 10 to 30 ° C / s
- the average cooling rate is set to 10 to 30 ° C./s. Preferably, it is 15 to 25 ° C./s.
- Winding temperature 470 to 700 ° C.
- low temperature transformation phase such as bainite is generated, and the total volume ratio of martensite grains having an average of the above ratio of not less than 1/4 and not more than 1 does not satisfy the desired range. Softening occurs in parts.
- the coiling temperature exceeds 700 ° C., Si and Mn diffuse to the surface of the steel sheet to easily deteriorate the corrosion resistance of the welded portion, and pearlite is also easily generated to lower the strength. Therefore, the winding temperature is set to 470 to 700.degree.
- the temperature is 500 ° C. or more and 600 ° C. or less.
- the cold rolling step is a step of cold rolling the hot rolled steel sheet obtained by the above method.
- the rolling ratio is not particularly limited. For example, it is preferable to adjust the rolling reduction in the range of 30 to 80%.
- an annealing process is performed.
- the cold rolled steel sheet obtained in the cold rolling step is heated to an annealing temperature range of 750 to 900 ° C.
- annealing is performed under the condition of annealing time: 30 to 200 seconds
- the average cooling rate to 600 ° C When cooling down to 10-40 ° C / s and 600 ° C, bending and bending back is performed with a roll with a radius of 1500 mm or less in total: 1 time or more and 4 times or less
- cooling stop temperature 400 ° C to 600 ° C, cooling stop temperature And hold for 2 to 200 seconds.
- Annealing temperature 750 to 900 ° C
- Annealing time 30 to 200 seconds (s)
- the annealing temperature is less than 750 ° C. or the annealing time is less than 30 seconds, the progress of recovery is delayed, and a sufficient martensite volume fraction can not be obtained.
- the annealing temperature exceeds 900 ° C.
- the volume fraction of the martensitic phase increases, the tempering area also increases, and the toughness of the heat affected zone decreases.
- the annealing time exceeds 200 seconds, a large amount of iron carbide precipitation may cause a decrease in ductility. Therefore, the annealing temperature is 750 to 900 ° C., more preferably 800 to 900 ° C., and the holding time is 30 to 200 seconds, more preferably 50 to 150 seconds.
- the average cooling rate to 600 ° C 10 to 40 ° C / s, when cooling to 600 ° C, bending and bending back with a roll with a radius of 1500 mm or less in total: 1 or more and 4 or less Cooling stop temperature: cooling is performed at a temperature of 400 to 600 ° C.
- Average cooling rate up to 600 ° C 10 to 40 ° C / s
- the average cooling rate exceeds 40 ° C./s, ferrite grains do not grow, and it can not be obtained that the total volume fraction of martensite grains having an average of the above ratio is 1/4 or more and 1 or less is 60% or more , Welding deformation strength is reduced.
- the average cooling rate to 600 ° C. is 10 to 40 ° C./s.
- the average cooling rate from 600 ° C. to the cooling stop temperature is not particularly limited. It is preferable to adjust in the range of 20 to 60 ° C./s.
- a total of one or more and four or less of bending and bending back with a radius of 1,500 mm or less can not obtain a desired steel structure by simply cooling. If the desired steel structure can not be obtained, the weld fatigue strength decreases. Therefore, in order to obtain a desired steel structure, cooling is performed to 600 ° C. at a cooling rate of 10 to 40 ° C./s while performing bending and bending back in a high temperature range from the annealing temperature to 600 ° C.
- the total volume fraction of martensite grains having an average of the above ratio of 1/4 or more and 1 or less can be adjusted by performing this bending and bending back, and a martensite grain having an average of the above ratio of 1/4 or more and 1 or less
- the total volume fraction of H is related to weld fatigue strength.
- the roll diameter needs to be 1500 mm or less.
- the total volume ratio of martensite grains having an average of the ratio of 1 ⁇ 4 or more and 1 or less is less than 60% if the number of times of bending and bending is 5 or more, and therefore the number is 4 or less. Preferably, it is three times or less.
- the number of times of bending and bending is not a combination of bending and bending back once but counting of once as bending and once as bending.
- Cooling stop temperature 400 to 600 ° C Holding time: 2 to 200 seconds
- tempered martensite increases and strength decreases.
- the cooling stop temperature is higher than 600 ° C.
- ferrite grain growth proceeds, and the toughness and fatigue strength of the heat affected zone decrease.
- the holding time exceeds 200 seconds, it is not preferable in terms of productivity, and bainite transformation proceeds to lower the strength.
- the holding time is less than 2 seconds
- the total volume fraction of martensite grains having an average of the ratio is not less than 1 ⁇ 4 and not more than 1 does not satisfy the desired range. Therefore, the cooling stop temperature is set to 400 to 600 ° C., and the holding time at the cooling stop temperature is set to 2 to 200 seconds.
- the method for producing a high strength steel sheet of the present invention is a method for producing a high strength steel sheet having a plating layer on the surface
- the production method of the present invention further has a plating step.
- the plating step is a step of plating the surface of the high strength steel plate.
- the method of a plating process can employ
- an alloying process may be performed.
- Hot rolling, cold rolling and annealing were performed on the slabs having the component compositions shown in Table 1 under the conditions shown in Table 2 to produce high strength steel plates. Here, no. About 1, 2, 9, 10, 19, 20, 23, 33, the plating process was performed.
- the plate thickness section of the obtained steel plate in the rolling direction was polished to reveal corrosion by 1% nital. It is magnified 2000 times with a scanning electron microscope, and the inside of the area from the surface to the 1/4 t plate thickness is photographed for 10 fields of view, and it is obtained by a cutting method according to ASTM E 112-10.
- t is the thickness of the steel plate (plate thickness).
- the area ratio of each phase was measured based on the photographed image. This area ratio was regarded as volume fraction.
- the ferrite phase is a structure having a form in which corrosion marks and cementite are not observed in the grains.
- Untempered martensite has no cementite in the grains and has brighter contrast than the ferrite phase, and tempered martensite is a structure in which corrosion marks and cementite are found in the grains.
- the average of the area ratio to the observation field of view was determined by image analysis for these phases.
- the region identified as untempered martensite contains a small amount of retained austenite. Therefore, in order to distinguish retained austenite from non-tempered martensite, measurement of retained austenite is performed by grinding to 1/4 position in the thickness direction and X-ray of plate surface subjected to chemical polishing of 200 ⁇ m or more The volume fraction of retained austenite phase was quantified by the diffraction intensity.
- the incident radiation source was measured from the peaks of (200) ⁇ , (211) ⁇ , (200) ⁇ , (220) ⁇ , and (311) ⁇ using MoK ⁇ rays.
- the value of the volume fraction of the obtained retained austenite phase was handled equivalent to the area ratio of the steel sheet structure.
- the martensite area ratio (volume fraction) of the present invention is a value obtained by adding the area ratio of tempered martensite by reducing the area ratio of retained austenite from the area ratio of unquenched martensite. In addition, bainite and perlite were confirmed as other phases.
- the average ratio of the grain size of the martensite grain to the adjacent ferrite grain in the entire martensite phase is 1 /
- the total volume fraction of martensite grains of 4 or more and 1 or less was measured.
- the average particle diameter of martensite and the average particle diameter of ferrite are magnified 1000 times with a scanning electron microscope (SEM), and photographed for 10 fields of view , According to ASTM E 112-10.
- SEM scanning electron microscope
- the calculated average grain size of martensite and the average grain size of ferrite are shown in Table 3.
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)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Heat Treatment Of Sheet Steel (AREA)
Abstract
Description
Cはマルテンサイトを生成させて強度を上昇させるために必要な元素である。C含有量が0.05%未満では、マルテンサイトの硬さが低く、降伏強さが550MPa以上にならない。そこで、C含有量は0.05%以上とする。好ましくは0.06%以上であり、より好ましくは0.07%以上である。特にC含有量を0.07%以上にすれば、溶接部疲労強度を表す十字引張試験の結果を300N以上にすることができる。一方、C含有量が0.15%を超えると熱影響部にセメンタイトが多量に生成して熱影響部でマルテンサイトとなった部分の靱性を低下させ、溶接部疲労強度が低下する。また、C含有量が0.15%を超えると、後述する比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が所望の範囲にならない場合がある。そこで、C含有量は0.15%以下とする。好ましくは0.13%以下、より好ましくは0.11%以下である。特にC含有量を0.11%以下にすれば、溶接部疲労強度を表す十字引張試験の結果を300N以上にすることができる。
Siは固溶強化により鋼板の硬度を高める作用を有する元素である。降伏強さを安定的に確保するために、Siは0.01%以上の含有を必要とする。好ましくは0.10%以上、より好ましくは0.35%以上である。Si含有量が0.35%以上であれば、溶接部疲労強度を表す十字引張試験の結果を300N以上にすることができる。さらに好ましくは0.51%以上である。一方、Si含有量は1.80%を超えると、溶接部の靱性が悪くなり、溶接疲労強度が低下する。そのため、上限を1.80%とする。好ましくは1.40%以下である。より好ましくは1.20%以下である。最も好ましくは1.00%以下である。Si含有量が1.00%以下であれば、溶接部疲労強度を表す十字引張試験の結果を300N以上にすることができる。
Mnは固溶強化により鋼板の硬度を高める作用を有する元素である。フェライト変態やベイナイト変態などを抑えてマルテンサイトを生成させて素材の強度を上昇させる元素である。降伏強さを安定的に確保するため、Mnは1.8%以上の含有を必要とする。好ましくは2.1%以上、より好ましくは2.2%以上である。Mn含有量が2.2%以上であれば、溶接部疲労強度を表す十字引張試験の結果を300N以上にすることができる。一方、Mn含有量が多くなると、焼き戻しでセメンタイト生成するとともに、熱影響部の靱性が低下し、溶接部疲労強度が低下するのでMnの上限は3.2%とする。好ましくは3.1%以下、より好ましくは2.9%以下である。Mn含有量が2.9%以下であれば、溶接部疲労強度を表す十字引張試験の結果を300N以上にすることができる。
Pは粒界に偏析して靱性を低下させる。そのため、上限0.05%以下とした。好ましくは0.03%以下であり、さらに好ましくは0.02%以下である。下限については特に限定されず、P含有量は少ない方が好ましいが、製造性の点から0.0001%以上が好ましい。
Sは、Mnと結合して粗大なMnSを形成し、靱性を低下させる。このため、S含有量は低減することが好ましい。0.020%以下であればよい。好ましくは0.010%以下であり、さらに好ましくは0.002%以下である。下限については特に限定されず、S含有量は少ない方が好ましいが、製造性の点から0.0001%以上が好ましい。
鋼中に酸化物が大量に存在すると靱性が低下することから脱酸は重要である。また、Alはセメンタイトの析出を抑制することがある。これらの効果を得るために、0.01%以上含有する必要がある。好ましくは0.02%以上、より好ましくは0.03%以上である。一方、2.0%を超えると、酸化物や窒化物が凝集粗大化して靱性を低下させるため、上限を2.0%以下とした。好ましくは1.5%以下、より好ましくは0.1%以下である。
Nは本発明においては有害な元素であり、極力低減することが好ましい。NはTiと結合してTiNを形成するが、N含有量が0.010%を超えると、形成されるTiN量が多くなることに起因して溶接部の靱性を劣化させる。したがって、N含有量は0.010%以下とする。好ましくは0.008%以下、より好ましくは0.006%以下である。
Bは粒界を強化して靱性向上に必要な元素である。効果を十分に得るには、Bの含有量は0.0001%以上にする必要がある。好ましくは0.001%以上である。一方、0.005%を超えると、BはFe23(CB)6を形成して靱性を劣化させる。このため、Bは0.005%以下にする。好ましくは0.004%以下である。
TiはNと結合し、窒化物を形成することにより、BNの形成を抑制し、Bの効果を引き出すとともに、TiNを形成させて結晶粒を微細化して靱性を向上させる。この効果を得るため、Tiの含有量は0.005%以上にする必要がある。好ましくは0.010%以上である。一方、Ti含有量が0.04%を超えると、この効果が飽和するだけではなく、圧延負荷を高めるため、安定した鋼板製造が困難になる。このため、Ti含有量は0.04%以下とする。好ましくは0.03%以下である。
Nbは本発明の効果をさらに向上させる元素である。Nbがマルテンサイト微細化や熱影響部の結晶粒の粗大化を防止して熱影響部の靱性を向上させる。この効果を得るためのNb含有量は0.005%以上である。好ましくは0.010%以上である。一方、Nb含有量が0.06%を超えると、後述する比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が所望の範囲に入らず、また、Nb炭化物が析出して靱性が逆に劣化してしまう。このため、Nb含有量は0.06%以下の範囲に限定する。好ましくは0.04%以下である。Nb含有量が0.04%以下であれば、溶接部疲労強度を表す十字引張試験の結果を300N以上にすることができる。また、溶接継手の液体金属脆性も抑制することで継手の強度を向上させることができる。
Moはオーステナイトの核生成を促進し、マルテンサイトを微細化させる。この効果を得るために、Moの含有量は0.03%以上にする必要がある。好ましくは0.04%以上である。一方、Moが粒界偏析すると、フェライトを粒成長が止まるため、フェライトが微細化しすぎる。これを抑制するため、Moの含有量は0.50%以下である。好ましくは、0.30%以下である。
Crは焼き戻し脆化を抑制する効果を持つ元素である。そのため、Crを含有することで本発明の効果はさらに増大する。このさらなる増大の効果を得るためには、Cr含有量を0.1%以上にする。好ましくは0.2%以上である。しかしながら、1.0%を超えての含有はCr炭化物の形成を招き熱影響部の靱性劣化を招く。そこで、Cr含有量は1.0%以下とする。好ましくは0.5%以下である。
マルテンサイト相は、硬質相であり、変態組織強化によって鋼板の強度を増加させる作用を有している。また、降伏強さを550MPa以上にするには、マルテンサイト相の体積分率は40%以上とする。好ましくは45%以上、より好ましくは50%以上である。一方、75%を超えると、熱影響部の靱性が低下する。このため、マルテンサイト相の体積分率は75%以下とする。好ましくは70%以下、より好ましくは65%以下、さらに好ましくは59%以下である。なお、上記体積分率は焼き入れままマルテンサイト(焼き戻されていないマルテンサイト)と焼き戻しマルテンサイトの合計体積分率を意味する。
マルテンサイト粒と隣接のフェライト粒の粒径の比(マルテンサイト粒径/フェライト粒径)の平均が1/4未満の割合が多くなると、HAZ部の粒成長により溶接部の強度が低下する。したがって、上記比の平均を1/4以上とする。一方、上記比の平均が1超の割合が多くなると、マルテンサイト粒が応力の集中を受けやすく、マルテンサイト粒の周辺にボイドが発生し、溶接部疲労強度が低下する。そこで、マルテンサイト粒と隣接のフェライト粒の粒径の比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率を60%以上とする。上限は特に限定されないが、90%以下が好ましく、より好ましくは85%以下、さらに好ましくは80%以下である。
仕上げ圧延終了後、巻取温度までの平均冷却速度が10℃/s未満であると、フェライト粒が成長せず、熱影響部の靱性が低下する。一方、30℃/sを超えると、フェライト粒が成長し過ぎで、強度が低下する。したがって、上記平均冷却速度を10~30℃/sとする。好ましくは15~25℃/sである。
巻取温度が470℃を下回ると、ベイナイトなど低温変態相が生成し、上記比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が所望の範囲を満たさなくなり、溶接熱影響部で軟化が生じる。一方、巻取温度が700℃を超えると、Si、Mnが鋼板表面に拡散して溶接部耐食性が劣化し易くなるとともに、パーライトも生じやすくなり、強度が低下する。したがって、巻取温度は470~700℃とする。好ましくは、500℃以上600℃以下である。
焼鈍時間:30~200秒(s)
マルテンサイトの体積分率が40~75%、且つマルテンサイト粒と隣接のフェライト粒の粒径の比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が60%以上である鋼組織にするには、冷間圧延後の鋼板を750~900℃の焼鈍温度で30~200秒保持して焼鈍する必要がある。焼鈍温度が750℃未満や焼鈍時間が30秒未満の場合、回復の進行が遅くなり、十分なマルテンサイト体積分率が得られない。一方、焼鈍温度が900℃を超えると、マルテンサイト相の体積分率が高くなり、焼き戻し領域も増えて、熱影響部の靱性が低下する。また、焼鈍時間が200秒を超えると、鉄炭化物の多量の析出により延性の低下を招くことがある。したがって、焼鈍温度は750~900℃、より好ましくは800~900℃、保持時間は30~200秒、より好ましく50~150秒とする。
平均冷却速度が40℃/s超になると、フェライト粒が成長せず、上記比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が60%以上であることが得られなくなり、溶接変形強度が低下する。一方、平均冷却速度が10℃/s未満になると、フェライト粒成長が進み、熱影響部の靱性及び疲労強度が低下する。したがって、600℃までの平均冷却速度は10~40℃/sとする。600℃から冷却停止温度までの平均冷却速度は特に限定されない。20~60℃/sの範囲で調整することが好ましい。
単純に冷却させるのみでは、所望の鋼組織が得られない。所望の鋼組織が得られないと溶接部疲労強度が低下する。そこで、所望の鋼組織を得るために、焼鈍温度から600℃までの高温範囲で曲げと曲げ戻しを行いながら、冷却速度10~40℃/sで600℃まで冷却する。この曲げ曲げ戻しを行うことで上記比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率を調整できることを見出し、上記比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が溶接部疲労強度に関係することを知見した。上記比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率を所望の範囲にするためには、ロール径は1500mm以下とする必要がある。また、曲げ曲げ戻し回数が5回以上では上記比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が60%未満になってしまうため、4回以下とした。好ましくは、3回以下である。なお、曲げ曲げ戻し回数とは、曲げと曲げ戻しを合わせて1回とするのではなく、曲げで1回、曲げ戻しで1回として回数を数える。
保持時間:2~200秒
400℃未満まで冷却すると、焼き戻しマルテンサイトが増え、強度が低下する。一方冷却停止温度を600℃超とすると、フェライト粒成長が進み、熱影響部の靱性及び疲労強度が低下する。保持時間が200秒超になると、生産性上好ましくないうえ、ベイナイト変態が進行し、強度が低下する。一方、保持時間が2秒未満になると、上記比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が所望の範囲を満たさなくなる。したがって、冷却停止温度を400~600℃、該冷却停止温度での保持時間を2~200秒とする。
得られた鋼板の圧延方向の板厚断面を研磨して、1%ナイタールによる腐食現出させた。走査型電子顕微鏡で2000倍に拡大して、表面から板厚1/4t部までの領域内を10視野分撮影し、ASTM E 112-10に準拠した切断法によって求める。tは鋼板の厚さ(板厚)である。上記撮影画像に基づき、各相の面積率を測定した。この面積率を体積分率とみなした。フェライト相は粒内に腐食痕やセメンタイトが観察されない形態を有する組織である。焼き戻しされていないマルテンサイトは粒内にセメンタイトが認められず、フェライト相よりも明るいコントラストであり、焼き戻しマルテンサイトは粒内に腐食痕やセメンタイトが認められる組織である。これらの相について画像解析により観察視野に対する面積率の平均を求めた。ここで、焼き戻しされていないマルテンサイトと識別された領域には少量の残留オーステナイト含まれる。そこで、焼き戻しされていないマルテンサイトと残留オーステナイトを区別するため、残留オーステナイトの測定について、板厚方向に対して1/4位置まで研削加工し、200μm以上化学研磨を施した板面のX線回折強度により残留オーステナイト相の体積分率を定量した。入射線源はMoKα線を用い、(200)α、(211)α、(200)γ、(220)γ、(311)γのピークから測定した。得られた残留オーステナイト相の体積分率の値は鋼板組織の面積率と同等に取り扱った。本発明のマルテンサイト面積率(体積分率)は、焼き戻しされていないマルテンサイト面積率から残留オーステナイトの面積率を減らして、焼き戻しマルテンサイトの面積率を足した値とした。なお、その他の相としてベイナイト、パーライトが確認された。
圧延方向と90°の方向(板幅方向)を長手方向(引張方向)とするJIS Z 2201に記載の5号試験片を用い、JIS Z 2241に準拠した引張試験を5回行い、平均の降伏強さ(YP)、引張強さ(TS)、突合せ伸び(EL)を求めた。算出結果を表3に示す。
まず、以下の条件にてスポット溶接を行った。電極:DR6mm-40R、加圧力:4802N(490kgf)、通電時間:17cyclesで行い、ナゲット径を6.5mmになるように電流値を調整し、十字引張試験片を作製した。その後疲労限を10^6回、試験速度20Hzで試験を行い、JIS Z 3137に基づき十字引張試験を行った。結果を表3に示す。
Claims (6)
- 質量%で、
C:0.05~0.15%、
Si:0.01~1.80%、
Mn:1.8~3.2%、
P:0.05%以下、
S:0.020%以下、
Al:0.01~2.0%、
N:0.010%以下を含有し、
さらに、
B:0.0001~0.005%、
Ti:0.005~0.04%および
Nb:0.005~0.06%のうち1種以上を含有し、残部が鉄および不可避的不純物からなる成分組成と、
圧延方向の板厚断面の観察において、体積分率で40~75%のマルテンサイト相を含有し、
該マルテンサイト相全体における、マルテンサイト粒と隣接のフェライト粒の粒径の比の平均が1/4以上1以下であるマルテンサイト粒の合計体積率が60%以上である鋼組織と、を有し、
降伏強さ(YP)が550MPa以上である高強度鋼板。 - 前記成分組成は、さらに、質量%で、
Mo:0.03~0.50%、
Cr:0.1~1.0%のいずれか1種以上を合計で1%以下含有する請求項1に記載の高強度鋼板。 - 前記成分組成は、さらに、質量%で、Cu、Ni、Sn、As、Sb、Ca、Mg、Pb、Co、Ta、W、REM、Zn、V、Sr、CsおよびHfのいずれか1種以上を合計で0.5%以下含有する請求項1または2に記載の高強度鋼板。
- 表面にめっき層を有する請求項1~3のいずれかに記載の高強度鋼板。
- 請求項1~3のいずれかに記載の成分組成を有する鋼スラブを熱間圧延後、平均冷却速度が10~30℃/sの条件で冷却し、巻取温度が470~700℃の条件で巻取る熱延工程と、
前記熱延工程で得られた熱延鋼板を冷間圧延する冷延工程と、
前記冷延工程で得られた冷延鋼板を、750~900℃の焼鈍温度域まで加熱し、焼鈍時間:30~200秒の条件で焼鈍し、600℃までの平均冷却速度:10~40℃/s、600℃までの冷却時に半径1500mm以下のロールで曲げ曲げ戻しを合計:1回以上4回以下、冷却停止温度:400~600℃の条件で冷却し、前記冷却停止温度で2~200秒保持する焼鈍工程と、を有する高強度鋼板の製造方法。 - 前記焼鈍工程後の鋼板の表面にめっき処理を施すめっき工程を有する請求項5に記載の高強度鋼板の製造方法。
Priority Applications (7)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2018535068A JP6443594B1 (ja) | 2017-10-20 | 2018-03-29 | 高強度鋼板およびその製造方法 |
US16/754,508 US11345973B2 (en) | 2017-10-20 | 2018-03-29 | High-strength steel sheet and method for manufacturing the same |
MX2020004029A MX2020004029A (es) | 2017-10-20 | 2018-03-29 | Lamina de acero de alta resistencia y metodo para la fabricacion de la misma. |
KR1020207010173A KR102398709B1 (ko) | 2017-10-20 | 2018-03-29 | 고강도 강판 및 그 제조 방법 |
CN202210373542.8A CN114703347A (zh) | 2017-10-20 | 2018-03-29 | 高强度钢板及其制造方法 |
CN201880067488.6A CN111247264A (zh) | 2017-10-20 | 2018-03-29 | 高强度钢板及其制造方法 |
EP18869192.7A EP3653745A4 (en) | 2017-10-20 | 2018-03-29 | HIGH-STRENGTH STEEL SHEET AND MANUFACTURING METHOD THEREOF |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2017203019 | 2017-10-20 | ||
JP2017-203019 | 2017-10-20 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2019077777A1 true WO2019077777A1 (ja) | 2019-04-25 |
Family
ID=66173261
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2018/013074 WO2019077777A1 (ja) | 2017-10-20 | 2018-03-29 | 高強度鋼板およびその製造方法 |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP3653745A4 (ja) |
CN (1) | CN111247264A (ja) |
WO (1) | WO2019077777A1 (ja) |
Cited By (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN111647801A (zh) * | 2020-05-11 | 2020-09-11 | 首钢集团有限公司 | 一种690MPa级铁素体马氏体双相钢、其制备方法及其应用 |
WO2021200580A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
WO2021200577A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
WO2021200579A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
WO2021200578A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN113737087B (zh) * | 2020-05-27 | 2022-07-19 | 宝山钢铁股份有限公司 | 一种超高强双相钢及其制造方法 |
CN113088816B (zh) * | 2021-03-27 | 2021-10-12 | 京泰控股集团有限公司 | 一种家具用钢制材料及其制备方法 |
CA3228109A1 (en) * | 2021-10-06 | 2023-04-13 | Vantage Alloys Ag | Alloyed steel |
Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4924730B1 (ja) | 1967-06-30 | 1974-06-25 | ||
JPS5412746B2 (ja) | 1973-10-30 | 1979-05-25 | ||
JPS5434960B1 (ja) | 1971-05-06 | 1979-10-30 | ||
JP2006342373A (ja) * | 2005-06-07 | 2006-12-21 | Sumitomo Metal Ind Ltd | 高張力溶融亜鉛めっき鋼板と製造方法 |
JP2010126787A (ja) * | 2008-11-28 | 2010-06-10 | Kobe Steel Ltd | 耐水素脆化特性および加工性に優れた超高強度鋼板とその製造方法 |
WO2013047755A1 (ja) * | 2011-09-30 | 2013-04-04 | 新日鐵住金株式会社 | 耐衝撃特性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法、並びに、高強度合金化溶融亜鉛めっき鋼板およびその製造方法 |
WO2015092982A1 (ja) * | 2013-12-18 | 2015-06-25 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
JP2016188395A (ja) | 2015-03-30 | 2016-11-04 | 新日鐵住金株式会社 | 溶接性と加工性に優れた高強度冷延鋼板とその製造方法 |
JP2017520681A (ja) * | 2014-06-06 | 2017-07-27 | アルセロールミタル | 高強度多相鋼、製造方法および使用 |
WO2018043452A1 (ja) * | 2016-08-30 | 2018-03-08 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
WO2018062342A1 (ja) * | 2016-09-30 | 2018-04-05 | Jfeスチール株式会社 | 高強度めっき鋼板及びその製造方法 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP5151246B2 (ja) * | 2007-05-24 | 2013-02-27 | Jfeスチール株式会社 | 深絞り性と強度−延性バランスに優れた高強度冷延鋼板および高強度溶融亜鉛めっき鋼板ならびにその製造方法 |
JP5194841B2 (ja) * | 2008-01-31 | 2013-05-08 | Jfeスチール株式会社 | 成形性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 |
JP5418168B2 (ja) * | 2008-11-28 | 2014-02-19 | Jfeスチール株式会社 | 成形性に優れた高強度冷延鋼板、高強度溶融亜鉛めっき鋼板およびそれらの製造方法 |
JP4924730B2 (ja) * | 2009-04-28 | 2012-04-25 | Jfeスチール株式会社 | 加工性、溶接性および疲労特性に優れる高強度溶融亜鉛めっき鋼板およびその製造方法 |
ES2645994T3 (es) * | 2011-09-30 | 2017-12-11 | Nippon Steel & Sumitomo Metal Corporation | Chapa de acero de alta resistencia, galvanizada por inmersión en caliente, y proceso para producirla |
CN106232839B (zh) * | 2014-04-22 | 2018-10-09 | 杰富意钢铁株式会社 | 高强度熔融镀锌钢板及高强度合金化熔融镀锌钢板的制造方法 |
EP3173494B1 (en) * | 2014-07-25 | 2019-03-13 | JFE Steel Corporation | Method for producing high-strength hot dipped galvanized steel sheet |
-
2018
- 2018-03-29 WO PCT/JP2018/013074 patent/WO2019077777A1/ja unknown
- 2018-03-29 CN CN201880067488.6A patent/CN111247264A/zh active Pending
- 2018-03-29 EP EP18869192.7A patent/EP3653745A4/en active Pending
Patent Citations (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS4924730B1 (ja) | 1967-06-30 | 1974-06-25 | ||
JPS5434960B1 (ja) | 1971-05-06 | 1979-10-30 | ||
JPS5412746B2 (ja) | 1973-10-30 | 1979-05-25 | ||
JP2006342373A (ja) * | 2005-06-07 | 2006-12-21 | Sumitomo Metal Ind Ltd | 高張力溶融亜鉛めっき鋼板と製造方法 |
JP2010126787A (ja) * | 2008-11-28 | 2010-06-10 | Kobe Steel Ltd | 耐水素脆化特性および加工性に優れた超高強度鋼板とその製造方法 |
WO2013047755A1 (ja) * | 2011-09-30 | 2013-04-04 | 新日鐵住金株式会社 | 耐衝撃特性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法、並びに、高強度合金化溶融亜鉛めっき鋼板およびその製造方法 |
WO2015092982A1 (ja) * | 2013-12-18 | 2015-06-25 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
JP2017520681A (ja) * | 2014-06-06 | 2017-07-27 | アルセロールミタル | 高強度多相鋼、製造方法および使用 |
JP2016188395A (ja) | 2015-03-30 | 2016-11-04 | 新日鐵住金株式会社 | 溶接性と加工性に優れた高強度冷延鋼板とその製造方法 |
WO2018043452A1 (ja) * | 2016-08-30 | 2018-03-08 | Jfeスチール株式会社 | 高強度鋼板およびその製造方法 |
WO2018062342A1 (ja) * | 2016-09-30 | 2018-04-05 | Jfeスチール株式会社 | 高強度めっき鋼板及びその製造方法 |
Cited By (25)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2022024145A (ja) * | 2020-03-31 | 2022-02-08 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
WO2021200578A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
CN115349028B (zh) * | 2020-03-31 | 2024-03-26 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
WO2021200579A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
JP7044195B2 (ja) | 2020-03-31 | 2022-03-30 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
JP2022020867A (ja) * | 2020-03-31 | 2022-02-01 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
JP2022020866A (ja) * | 2020-03-31 | 2022-02-01 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
JP7044196B2 (ja) | 2020-03-31 | 2022-03-30 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
JP7001203B1 (ja) * | 2020-03-31 | 2022-02-03 | Jfeスチール株式会社 | 鋼板及び部材 |
JP7001204B1 (ja) * | 2020-03-31 | 2022-02-03 | Jfeスチール株式会社 | 鋼板及び部材 |
JP7001202B1 (ja) * | 2020-03-31 | 2022-02-03 | Jfeスチール株式会社 | 鋼板及び部材 |
JP2022024144A (ja) * | 2020-03-31 | 2022-02-08 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
WO2021200577A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
WO2021200580A1 (ja) * | 2020-03-31 | 2021-10-07 | Jfeスチール株式会社 | 鋼板、部材及びそれらの製造方法 |
JP7001205B1 (ja) * | 2020-03-31 | 2022-02-03 | Jfeスチール株式会社 | 鋼板及び部材 |
JP7044198B2 (ja) | 2020-03-31 | 2022-03-30 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
JP7044197B2 (ja) | 2020-03-31 | 2022-03-30 | Jfeスチール株式会社 | 鋼板の製造方法及び部材の製造方法 |
CN115349028A (zh) * | 2020-03-31 | 2022-11-15 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
CN115362279A (zh) * | 2020-03-31 | 2022-11-18 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
CN115362275A (zh) * | 2020-03-31 | 2022-11-18 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
CN115362277A (zh) * | 2020-03-31 | 2022-11-18 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
CN115362279B (zh) * | 2020-03-31 | 2024-03-01 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
CN115362275B (zh) * | 2020-03-31 | 2024-03-01 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
CN115362277B (zh) * | 2020-03-31 | 2024-03-12 | 杰富意钢铁株式会社 | 钢板、部件及其制造方法 |
CN111647801A (zh) * | 2020-05-11 | 2020-09-11 | 首钢集团有限公司 | 一种690MPa级铁素体马氏体双相钢、其制备方法及其应用 |
Also Published As
Publication number | Publication date |
---|---|
EP3653745A4 (en) | 2020-07-15 |
EP3653745A1 (en) | 2020-05-20 |
CN111247264A (zh) | 2020-06-05 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US10745775B2 (en) | Galvannealed steel sheet and method for producing the same | |
JP5858199B2 (ja) | 高強度溶融亜鉛めっき鋼板及びその製造方法 | |
JP5194878B2 (ja) | 加工性および溶接性に優れる高強度溶融亜鉛めっき鋼板およびその製造方法 | |
WO2019077777A1 (ja) | 高強度鋼板およびその製造方法 | |
JP6787523B1 (ja) | 高強度鋼板およびその製造方法 | |
JPWO2019106895A1 (ja) | 高強度亜鉛めっき鋼板およびその製造方法 | |
JP2011168876A (ja) | 加工性および耐衝撃特性に優れた高強度溶融亜鉛めっき鋼板およびその製造方法 | |
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 | |
WO2017169939A1 (ja) | 薄鋼板およびめっき鋼板、並びに、熱延鋼板の製造方法、冷延フルハード鋼板の製造方法、熱処理板の製造方法、薄鋼板の製造方法およびめっき鋼板の製造方法 | |
KR102245008B1 (ko) | 고강도 강판 및 그 제조 방법 | |
JP6432705B2 (ja) | 高強度めっき鋼板及びその製造方法 | |
WO2016103534A1 (ja) | 高強度溶融亜鉛めっき鋼板およびその製造方法 | |
JP6458911B1 (ja) | 高強度鋼板およびその製造方法 | |
KR102398709B1 (ko) | 고강도 강판 및 그 제조 방법 | |
JP7044196B2 (ja) | 鋼板の製造方法及び部材の製造方法 | |
JP7044195B2 (ja) | 鋼板の製造方法及び部材の製造方法 | |
JP4692519B2 (ja) | 高強度溶融亜鉛メッキ鋼板およびその製造方法 | |
WO2015194572A1 (ja) | 衝突特性に優れる超高強度鋼板 | |
CN117916398A (zh) | 冷轧钢板及其制造方法以及焊接接头 |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
ENP | Entry into the national phase |
Ref document number: 2018535068 Country of ref document: JP Kind code of ref document: A |
|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 18869192 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2018869192 Country of ref document: EP Effective date: 20200212 |
|
ENP | Entry into the national phase |
Ref document number: 20207010173 Country of ref document: KR Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |