WO2020195009A1 - Corps moulé par estampage à chaud - Google Patents

Corps moulé par estampage à chaud Download PDF

Info

Publication number
WO2020195009A1
WO2020195009A1 PCT/JP2020/000630 JP2020000630W WO2020195009A1 WO 2020195009 A1 WO2020195009 A1 WO 2020195009A1 JP 2020000630 W JP2020000630 W JP 2020000630W WO 2020195009 A1 WO2020195009 A1 WO 2020195009A1
Authority
WO
WIPO (PCT)
Prior art keywords
less
hot
rotation angle
length
grain boundaries
Prior art date
Application number
PCT/JP2020/000630
Other languages
English (en)
Japanese (ja)
Inventor
由明 本多
由梨 戸田
匹田　和夫
智仁 田中
Original Assignee
日本製鉄株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 日本製鉄株式会社 filed Critical 日本製鉄株式会社
Priority to JP2021508099A priority Critical patent/JP7350057B2/ja
Publication of WO2020195009A1 publication Critical patent/WO2020195009A1/fr

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
    • C21D1/18—Hardening; Quenching with or without subsequent tempering
    • 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
    • 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
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur

Definitions

  • the present invention relates to a hot stamp molded body that is suitably used for automobiles, structural members of structures, reinforcing members, and the like that require strength.
  • the present application claims priority based on Japanese Patent Application No. 2019-057145 filed in Japan on March 25, 2019, the contents of which are incorporated herein by reference.
  • the conventional hot stamping compact manufactured by press quenching at the time of hot stamping has poor deformability because the entire area in the plate thickness direction is formed of a hard structure (mainly martensite).
  • a hard structure mainly martensite.
  • Patent Document 1 the crystal grain size of martensite is made finer by controlling the Mn content or the total content of at least one of Cr, Mo, Cu, and Ni and Mn, and the strength is high.
  • Patent Document 2 discloses a technique for improving collision resistance by finening the average crystal grain size of old austenite grains by selecting an alloying element.
  • the present inventors have diligently studied a method for solving the above problems.
  • the movement of dislocations in martensite may be promoted to enhance the deformability.
  • the crystal grains of martensite are finely divided, the grain boundary area is large, and dislocations that have moved within the grains are dammed at the grain boundaries, so that the deformability is low. Therefore, the present inventors have investigated a method for promoting the movement of dislocations even if the grain boundary area is large. As a result, the present inventors can facilitate the movement of dislocations between crystal grains by increasing the proportion of grain boundaries having the lowest angle among the four types of grain boundaries contained in martensite.
  • the present inventors have a rotation angle of 57 ° with the ⁇ 011> direction as the rotation axis among the grain boundaries having an average crystal orientation difference of 5 ° or more in crystal grains having a body-core structure such as martensite.
  • the length of the grain boundary of about 63 °, the length of the grain boundary of the rotation angle of 49 ° to 56 °, the length of the grain boundary of the rotation angle of 4 ° to 12 °, and the rotation angle of 64 ° to 72 Bending of hot stamped products by controlling the ratio of the length of grain boundaries whose rotation angle is 4 ° to 12 ° to 15% or more of the total length with the length of grain boundaries that is °. It was found that the sex was improved.
  • the present inventors have studied a method of increasing the ratio of the length of the grain boundary having a rotation angle of 4 ° to 12 ° with the ⁇ 011> direction as the rotation axis. As a result, the present inventors have made the steel plate contain 3.0% by mass or more of Ni, and controlled the average crystal grain size of austenite before the martensitic transformation to 10 ⁇ m or less.
  • the length of the grain boundaries with the rotation angle of 57 ° to 63 ° with the ⁇ 011> direction as the rotation axis and the rotation angle of 49 ° For the total length of the grain boundaries with a rotation angle of ⁇ 56 °, the grain boundaries with a rotation angle of 4 ° to 12 °, and the grain boundaries with a rotation angle of 64 ° to 72 °. , It has been found that the ratio of the length of grain boundaries having a rotation angle of 4 ° to 12 ° can be controlled to 15% or more.
  • Ni has the effect of improving the deformability of austenite by dissolving it in austenite.
  • the stress associated with the transformation is applied to the austenite due to the change in the crystal structure, and an advantageous grain boundary is generated to relieve this stress. Since the effect of stress relaxation is greater as the grain boundary has a larger rotation angle, the grain boundary having the highest rotation angle, which has a rotation angle of 64 ° to 72 ° with the rotation axis in the ⁇ 011> direction, is usually given priority.
  • the present inventors have found that the generation of stress associated with martensitic transformation can be alleviated by improving the deformability of austenite by containing Ni.
  • the present inventors have increased the rate of formation of subgrain boundaries in the hot stamping steel sheet and rapidly heated in the heating step during hot stamping to obtain average crystals of the former austenite grains. It has been found that the particle size can be controlled to 10 ⁇ m or less. As a result, since the grain boundary area of austenite is increased, the present inventors can easily deform (displace) between crystal grains and enhance the effect of relaxing the stress generated by the martensitic transformation. I found.
  • the present inventors examined a method for finely granulating old austenite grains.
  • the dislocations in the austenite are easily transferred, so that the austenite grains are easily coarsened. Therefore, in order to obtain fine old austenite grains in Ni-containing steel, it is effective to delay the start of transformation by raising the transformation temperature to austenite. In order to raise the transformation temperature to austenite, it is effective to utilize grain boundaries with low carbon concentration as reverse transformation sites for austenite.
  • the inventors investigated a method for obtaining fine old austenite grains by generating grain boundaries having a low carbon concentration in a steel sheet for hot stamping.
  • the present inventors can generate a metal structure called granular bainite by hot rolling a steel sheet containing Ni under predetermined conditions, and the granular bainite can be used. It was found that a bainite grain boundary and a subgrain boundary are included, a high concentration of carbon is concentrated in the bainite grain boundary, and the segregation of carbon is suppressed in the subgrain boundary.
  • Granular bainite containing large-angle grain boundaries and sub-grain boundaries is a metallographic structure formed through the following two steps. In the first stage, the transformation from austenite to bainitic ferrite occurs. In the second stage, the grain boundaries between bainitic ferrite are restored to subgrain boundaries, which become granular bainite.
  • the hot rolling process hot rolling is completed at a temperature of 800 ° C. or higher, and winding is performed in a temperature range of 500 ° C. or higher and 770 ° C. or lower.
  • the recrystallization rate of austenite before transformation that is, the dislocation density. If the recrystallization of austenite is promoted too much, the dislocation density in austenite will decrease, and a desired amount of granular bainite cannot be obtained. On the other hand, even if recrystallization is insufficient, the dislocation density in austenite increases too much, and transformation to granular bainite does not occur.
  • austenite is transformed into bainitic ferrite by winding in a temperature range of 500 ° C. or higher and 770 ° C. or lower.
  • the average cooling rate of the hot-rolled steel sheet being wound in the temperature range from 650 ° C to 400 ° C is controlled to 50 ° C / s or less.
  • the grain boundaries between bainitic ferrite are restored and subgrain boundaries are formed, thereby forming granular bainite.
  • granular bainite can be generated in the hot rolling process.
  • the average cooling rate in the above temperature range exceeds 50 ° C./s, the grain boundaries are restored and subgrain boundaries cannot be formed.
  • the initial bainitic ferrite In cooling during winding, the initial bainitic ferrite has grain boundaries with an average crystal orientation difference of 5 ° or more, but the average cooling rate is slow at 50 ° C / s or less in the temperature range where Fe can diffuse.
  • dislocation recovery occurs in the vicinity of the grain boundaries of bainitic ferrite, and subgrain boundaries having an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less are generated.
  • C in the steel diffuses from the subgrain boundaries to the surrounding large-angle grain boundaries, so it is possible to reduce the segregation of carbon at the subgrain boundaries.
  • the mobility of dislocations is increased, the recovery of dislocations is promoted, and the amount of subgrain boundaries generated is increased, so that the average crystal orientation difference is 0.4 ° or more.
  • the average crystal orientation difference is 0.4 ° or more and 3.0 ° or less with respect to the total of the grain boundary length of 3.0 ° or less and the grain boundary length of the average crystal orientation difference of more than 3.0 °.
  • the ratio of the grain boundary length of the austenite is 60% or more, and the number of reverse transformation sites of austenite can be increased during hot stamp heating, which contributes to the refinement of the old austenite grains.
  • the hot stamp molded product according to one aspect of the present invention has a chemical composition of mass%. C: 0.15% or more, less than 0.70%, Si: 0.010% or more, less than 0.50%, Mn: 0.010% or more, less than 3.00%, sol.
  • Al 0.0002% or more, 3.000% or less, Ni: 3.0% or more and less than 15.0%, P: 0.100% or less, S: 0.1000% or less, N: 0.0100% or less, Nb: 0% or more, 0.150% or less, Ti: 0% or more, 0.150% or less, Mo: 0% or more, 1.000% or less, Cr: 0% or more, 1.000% or less, B: 0% or more, 0.0100% or less, V: 0% or more, 1.0000% or less, Cu: 0% or more, 1.0000% or less, Sn: 0% or more, 1.000% or less, W: 0% or more, 1.000% or less, Ca: 0% or more, 0.010% or less, and REM: 0% or more, 0.300% or less,
  • the rest consists of Fe and impurities
  • the average crystal grain size of the former austenite grains is 10 ⁇ m or less, Of the grain boundaries with an average crystal orientation difference of 5 ° or more in the crystal grains having
  • the hot stamp molded product according to the above [1] has a chemical composition of mass%.
  • Nb 0.010% or more, 0.150% or less, Ti: 0.010% or more, 0.150% or less, Mo: 0.005% or more, 1.000% or less, Cr: 0.005% or more, 1.000% or less, B: 0.0005% or more, 0.0100% or less, V: 0.0005% or more, 1.0000% or less, Cu: 0.0010% or more, 1.0000% or less, Sn: 0.001% or more, 1.000% or less, W: 0.001% or more, 1.000% or less, It may contain one or more of the group consisting of Ca: 0.001% or more and 0.010% or less, and REM: 0.001% or more and 0.300% or less.
  • the hot stamp molded product according to the above [1] or [2] may have a plating layer on its surface.
  • the hot stamp molded product according to any one of the above [1] to [3] may have a softened region in a part thereof.
  • the hot stamped body according to the present embodiment has a chemical composition of C: 0.15% or more and less than 0.70%, Si: 0.010% or more and less than 0.50%, Mn: 0 in mass%. .010% or more, less than 3.00%, sol. Al: 0.0002% or more, 3.000% or less, Ni: 3.0% or more and less than 15.0%, P: 0.100% or less, S: 0.1000% or less, N: 0.0100%
  • Fe and impurities are included.
  • each element will be described in detail.
  • C 0.15% or more, less than 0.70%
  • C is an important element for obtaining the desired hardness for automobile members and the like in a hot stamp molded product. If the C content is less than 0.15%, the martensite is soft and it is difficult to obtain the desired hardness. Therefore, the C content is set to 0.15% or more.
  • the C content is preferably 0.30% or more.
  • the C content is preferably 0.50% or less.
  • Si: 0.010% or more, less than 0.50% Si is an element that enhances the deformability of the hot stamped article and contributes to the improvement of toughness. If the Si content is less than 0.010%, the deformability is poor and the toughness of the hot stamp molded product deteriorates. Therefore, the Si content is set to 0.010% or more. Even if the Si content is 0.50% or more, the above effect is saturated, so the Si content is set to less than 0.50%.
  • Mn 0.010% or more, less than 3.00% Mn is an element that contributes to improving the hardness of the hot stamped molded product by strengthening the solid solution. If the Mn content is less than 0.010%, the solid solution strengthening ability is poor, martensite becomes soft, and it becomes difficult to obtain the desired hardness for automobile members and the like. Therefore, the Mn content is set to 0.010% or more. The Mn content is preferably 0.70% or more. On the other hand, when the Mn content is 3.00% or more, the martensite becomes brittle and the toughness of the hot stamped molded product is impaired. Therefore, the Mn content is set to less than 3.00%.
  • sol.Al 0.0002% or more, 3.000% or less
  • Al is an element having an action of deoxidizing molten steel to make the steel sound (suppressing the occurrence of defects such as blow holes in the steel). sol. If the Al content is less than 0.0002%, deoxidation is not sufficient. The Al content is 0.0002% or more. sol. The Al content is preferably 0.001% or more. On the other hand, sol. When the Al content exceeds 3.000%, coarse oxides are generated and the toughness of the hot stamped compact is impaired. The Al content is 3.000% or less. In this embodiment, sol. Al means acid-soluble Al, and indicates solid solution Al existing in steel in a solid solution state.
  • Ni 3.0% or more and less than 15.0%
  • Ni is an element having an effect of refining old austenite grains, and is also an element necessary for obtaining a desired amount of granular bainite in a hot rolling process. Since the above effect cannot be obtained when the Ni content is less than 3.0%, the Ni content is set to 3.0% or more.
  • the Ni content is preferably 5.0% or more in order to further enhance the ability to absorb impact energy at low temperatures.
  • the Ni content is 15.0% or more, the martensite becomes brittle and the toughness of the hot stamped molded product is impaired. Therefore, the Ni content is set to less than 15.0%.
  • the Ni content is preferably less than 12.0%.
  • P 0.100% or less
  • P is an element that segregates at the grain boundaries and reduces the strength of the grain boundaries.
  • the P content is set to 0.100% or less.
  • the P content is preferably 0.050% or less.
  • the lower limit of the P content is not particularly limited, but if it is reduced to less than 0.0001%, the cost of removing P is significantly increased, which is economically unfavorable. Therefore, 0.0001% is a practical lower limit on the practical steel sheet. is there.
  • S 0.1000% or less
  • S is an element that forms inclusions in steel. If the S content exceeds 0.1000%, inclusions are formed in the steel and the bendability of the hot stamped compact is lowered, so the S content is set to 0.1000% or less.
  • the S content is preferably 0.0050% or less.
  • the lower limit of the S content is not particularly limited, but if it is reduced to less than 0.0015%, the cost of removing S is significantly increased, which is economically unfavorable. Therefore, 0.0015% is a practical lower limit on the practical steel sheet. is there.
  • N 0.0100% or less
  • N is an impurity element, which is an element that forms a nitride and lowers the bendability of the hot stamp molded product. If the N content exceeds 0.0100%, coarse nitrides are formed in the steel and the bendability of the hot stamped compact is significantly reduced. Therefore, the N content is set to 0.0100% or less.
  • the N content is preferably 0.0075% or less.
  • the lower limit of the N content is not particularly limited, but if it is reduced to less than 0.0001%, the N removal cost will increase significantly, which is economically unfavorable. Therefore, 0.0001% is a practical lower limit on the practical steel sheet. is there.
  • the rest of the chemical composition of the hot stamped article according to this embodiment is Fe and impurities.
  • impurities include elements that are unavoidably mixed from steel raw materials or scrap and / or in the steelmaking process and are allowed as long as they do not impair the characteristics of the hot stamped article according to the present embodiment.
  • the hot stamp molded product according to the present embodiment may contain the following elements as optional elements. When the following optional elements are not contained, the content is 0%.
  • Nb 0% or more, 0.150% or less Since Nb is an element that contributes to improving the hardness of the hot stamped molded product by strengthening the solid solution, it may be contained if necessary. When Nb is contained, if it is less than 0.010%, a sufficient effect cannot be obtained by containing Nb, so it is preferable to contain Nb in an amount of 0.010% or more. The Nb content is more preferably 0.035% or more. On the other hand, even if the Nb content exceeds 0.150%, the above effect is saturated, so the Nb content is set to 0.150% or less. The Nb content is preferably 0.120% or less.
  • Ti 0% or more, 0.150% or less Since Ti is an element that contributes to improving the hardness of the hot stamped molded product by strengthening the solid solution, it may be contained as necessary. When Ti is contained, if it is less than 0.010%, a sufficient effect due to the Ti content cannot be obtained. Therefore, the Ti content is preferably 0.010% or more. The Ti content is more preferably 0.020% or more. On the other hand, even if the Ti content exceeds 0.150%, the above effect is saturated, so the Ti content is set to 0.150% or less. The Ti content is preferably 0.120% or less.
  • Mo 0% or more, 1.000% or less Since Mo is an element that contributes to improving the hardness of the hot stamped molded product by strengthening the solid solution, it may be contained if necessary. When Mo is contained, if it is less than 0.005%, a sufficient effect cannot be obtained by the Mo content, so the Mo content is preferably 0.005% or more. The Mo content is more preferably 0.010% or more. On the other hand, even if the Mo content exceeds 1.000%, the above effect is saturated, so the Mo content is set to 1.000% or less. The Mo content is preferably 0.800% or less.
  • Cr 0% or more, 1.000% or less Since Cr is an element that contributes to improving the hardness of the hot stamped molded product by strengthening the solid solution, it may be contained as necessary. When Cr is contained, if the Cr content is less than 0.005%, a sufficient effect due to the Cr content cannot be obtained. Therefore, the Cr content is preferably 0.005% or more. The Cr content is more preferably 0.010% or more. On the other hand, even if the Cr content exceeds 1.000%, the above effect is saturated, so the Cr content is set to 1.000% or less. The Cr content is preferably 0.800% or less.
  • B 0% or more, 0.0100% or less Since B is an element that segregates at the grain boundaries and improves the strength of the grain boundaries, it may be contained as necessary. When B is contained, if the B content is less than 0.0005%, a sufficient effect cannot be obtained by the B content, so the B content is preferably 0.0005% or more. The B content is more preferably 0.0010% or more. On the other hand, even if the B content exceeds 0.0100%, the above effect is saturated, so the B content is set to 0.0100% or less. The B content is preferably 0.0075% or less.
  • V 0% or more, 1.0000% or less Since V is an element that contributes to improving the hardness of the hot stamped molded product by strengthening the solid solution, it may be contained if necessary. When V is contained, if the V content is less than 0.0005%, a sufficient effect cannot be obtained by the V content, so the V content is preferably 0.0005% or more. The V content is more preferably 0.0100% or more. On the other hand, even if the V content exceeds 1.0000%, the above effect is saturated, so the V content is set to 1.0000% or less. The V content is preferably 0.8000% or less.
  • Cu 0% or more, 1.0000% or less Since Cu is an element that contributes to improving the hardness of the hot stamped molded product by strengthening the solid solution, it may be contained if necessary. When Cu is contained, if the Cu content is less than 0.0010%, a sufficient effect cannot be obtained by the Cu content, so the Cu content is preferably 0.0010% or more. The Cu content is more preferably 0.0100% or more. On the other hand, even if the Cu content exceeds 1.0000%, the above effect is saturated, so the Cu content is set to 1.0000% or less. The Cu content is preferably 0.8000% or less.
  • Sn 0% or more, 1.000% or less Since Sn is an element having an action of deoxidizing molten steel to make the steel sound, it may be contained up to 1.000%. In order to ensure the above effect, the Sn content is preferably 0.001% or more.
  • W 0% or more, 1.000% or less Since W is an element having an action of deoxidizing molten steel to make the steel sound, it may be contained up to 1.000%. In order to ensure that the above effects are exhibited, the W content is preferably 0.001% or more.
  • Ca 0% or more, 0.010% or less Since Ca is an element having an action of deoxidizing molten steel to make the steel sound, it may be contained up to 0.010%. In order to surely exert the above effect, the Ca content is preferably 0.001% or more.
  • REM 0% or more, 0.300% or less Since REM is an element having an action of deoxidizing molten steel to make the steel sound, it may be contained up to 0.300%. In order to ensure the above effect, the REM content is preferably 0.001% or more.
  • REM is a general term for a total of 17 elements composed of Sc, Y and lanthanoid, and the content of REM means the total amount of the above elements.
  • REM is often contained by mischmetal, but may contain elements of the lanthanoid series in combination with La and Ce. Even when a lanthanide series element is contained in a composite manner in addition to La and Ce, the hot stamp molded product according to the present embodiment can exert its effect. Further, even if a metal REM such as metal La or Ce is contained, the hot stamp molded product according to the present embodiment can exert its effect.
  • the chemical composition of the hot stamped product described above may be measured by a general analysis method.
  • ICP-AES Inductively Coupled Plasma-Atomic Emission Spectrometry
  • C and S may be measured by using the combustion-infrared absorption method
  • N may be measured by using the inert gas melting-thermal conductivity method.
  • sol. Al may be measured by ICP-AES using a solution obtained by thermally decomposing the sample with an acid.
  • Step plate for hot stamping A sub-crystal grain (granular bainite) with an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less is placed inside a crystal grain surrounded by grain boundaries with an average crystal orientation difference of 5 ° or more. Including 10% or more in rate "
  • the steel sheet for hot stamping has a granular bainite (with an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less existing inside the crystal grains surrounded by grain boundaries having an average crystal orientation difference of 5 ° or more). It is necessary to contain 10% or more of a certain subcrystal grain) in terms of area ratio.
  • Granular bainite produced in the hot rolling step can be transformed into austenite through a predetermined heat treatment step (cold rolling if necessary) and finally obtain a desired metallographic structure in a hot stamped body. it can.
  • the area ratio of granular bainite is set to 10% or more.
  • the area ratio is 15% or more, 20% or more, 25% or more, and 30% or more.
  • the upper limit is not particularly limited, but the area ratio of granular bainite may be less than 95%.
  • the remainder of the metallographic structure is not particularly limited, but is usually one or more of ferrite, upper bainite, lower bainite, martensite, tempered martensite, retained austenite, iron-based carbides and alloy carbides.
  • the hot stamping steel sheet applied to the hot stamping compact according to the present embodiment may contain more than 5% and 90% or less of these metal structures.
  • a sample is cut out from a position 50 mm or more away from the end face of the hot stamping steel plate so that a cross section perpendicular to the surface (thick cross section) can be observed.
  • the size of the sample shall be such that it can be observed by about 10 mm in the rolling direction, although it depends on the measuring device.
  • the plate thickness 1/2 position is subjected to EBSD analysis at a measurement interval of 0.2 ⁇ m to obtain crystal orientation information.
  • the EBSD analysis is performed at 200 to 300 points / sec using an apparatus composed of a thermal field emission scanning electron microscope (JSM-7001F manufactured by JEOL) and an EBSD detector (DVC5 type detector manufactured by TSL). Perform at analysis speed.
  • JSM-7001F thermal field emission scanning electron microscope
  • DVC5 type detector manufactured by TSL
  • the area ratio of granular bainite is determined by, for example, the "Grain Average” installed in the software "OIM Analysis (registered trademark)" attached to the EBSD analyzer. If the "Missionation” function is used, it can be calculated easily. With this function, it is possible to calculate the orientation difference between adjacent measurement points for a crystal grain having a body-centered structure, and then obtain an average value for all the measurement points in the crystal grain. With respect to the obtained crystal orientation information, a region surrounded by grain boundaries with an average crystal orientation difference of 5 ° or more is defined as a crystal grain, and the "Grain Average Missionation" function allows the average crystal orientation difference within the crystal grains to be determined. By calculating the area ratio of the region (subgrain boundary) of 0.4 ° or more and 3.0 ° or less, the area ratio of granular bainite can be obtained.
  • the grain boundary length and the average crystal orientation difference having an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less are 3.
  • the ratio of the grain boundary lengths having an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less to the total lengths of grain boundaries exceeding 0 ° is 60% or more.
  • the ratio of the length of the grain boundaries is preferably 70% or more, or 80% or more.
  • the upper limit is not particularly limited, but may be less than 95%.
  • a sample is cut out from a position 50 mm or more away from the end face of the hot stamping steel plate so that a cross section perpendicular to the surface (thick cross section) can be observed.
  • the size of the sample shall be such that it can be observed by about 10 mm in the rolling direction, although it depends on the measuring device.
  • a diamond powder having a particle size of 1 to 6 ⁇ m is mirror-surfaced using a diluted solution such as alcohol or a liquid dispersed in pure water. Finish. Next, polishing at room temperature with colloidal silica containing no alkaline solution for 8 minutes to remove the strain introduced into the surface layer of the sample. Crystal orientation information is obtained by measuring a region having a length of 50 ⁇ m and a depth of 50 ⁇ m from the surface of the steel sheet at an arbitrary position in the longitudinal direction of the sample cross section by an electron backscatter diffraction method at a measurement interval of 0.1 ⁇ m.
  • an apparatus composed of a thermal field emission scanning electron microscope (JSM-7001F manufactured by JEOL) and an EBSD detector (DVC5 type detector manufactured by TSL) is used.
  • the degree of vacuum in the apparatus is 9.6 ⁇ 10-5 Pa or less
  • the acceleration voltage is 15 kV
  • the irradiation current level is 13
  • the irradiation time of the electron beam is 0.01 seconds / point.
  • the obtained crystal orientation information has an average crystal orientation difference of 0.4 ° or more and 3.0 °.
  • Grain boundaries with an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less with respect to the total length of the following grain boundaries and the lengths of grain boundaries with an average crystal orientation difference of more than 3.0 ° Calculate the ratio of the length of. With this function, it is possible to calculate the total length of grain boundaries having arbitrary rotation angles for the grain boundaries of crystal grains having a body-centered structure. For all the crystal grains included in the measurement area, the total length of these grain boundaries was calculated, and the grain boundary length and average crystal orientation with an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less were calculated. The ratio of the lengths of the grain boundaries having an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less to the total lengths of the grain boundaries having a difference of more than 3.0 ° is calculated.
  • the thickness of the hot stamping steel plate applied to the hot stamping compact according to the present embodiment is not particularly limited, but is preferably 0.5 to 3.5 mm from the viewpoint of reducing the weight of the vehicle body.
  • Average crystal grain size of old austenite grains 10 ⁇ m or less
  • the average crystal grain size of austenite before the martensitic transformation is 10 ⁇ m or less
  • the grain boundaries where the average crystal orientation difference in the crystal grains having a body-core structure such as martensitic after the martensitic transformation is 5 ° or more ⁇ 011>
  • the length of the grain boundary where the rotation angle is 57 ° to 63 °, the length of the grain boundary where the rotation angle is 49 ° to 56 °, and the rotation angle are 4 ° to 12 ° with the direction as the rotation axis.
  • the average crystal grain size of the old austenite grains is set to 10 ⁇ m or less.
  • the average crystal grain size of the former austenite grains is preferably 8 ⁇ m or less.
  • the lower limit is not particularly limited, but since the average crystal grain size of the old austenite grains that can be realized in normal actual operation is 2 ⁇ m or more, the lower limit of the average crystal grain size of the old austenite grains may be 2 ⁇ m.
  • the length of the grain boundary and the rotation angle at which the rotation angle is 57 ° to 63 ° with the ⁇ 011> direction as the rotation axis The total length of the grain boundaries with a rotation angle of 49 ° to 56 °, the grain boundaries with a rotation angle of 4 ° to 12 °, and the grain boundaries with a rotation angle of 64 ° to 72 °.
  • the ratio of the length of the grain boundary where the rotation angle is 4 ° to 12 ° is 15% or more.
  • the length of the grain boundary and the rotation angle at which the rotation angle is 57 ° to 63 ° with the ⁇ 011> direction as the rotation axis are The total length of the grain boundaries with a rotation angle of 49 ° to 56 °, the length of the grain boundaries with a rotation angle of 4 ° to 12 °, and the length of the grain boundaries with a rotation angle of 64 ° to 72 °.
  • the ratio of the length of the grain boundaries having the rotation angle of 4 ° to 12 ° is less than 15%, the bendability of the hot stamped molded product cannot be improved.
  • the rotation angle is 57 ° to 57 ° with the ⁇ 011> direction as the rotation axis among the grain boundaries having an average crystal orientation difference of 5 ° or more in the crystal grains having a body-core structure.
  • the length of the grain boundary is 63 °
  • the length of the grain boundary is 49 ° to 56 °
  • the length of the grain boundary is 4 ° to 12 °
  • the rotation angle is 64 ° to 72 °.
  • the ratio of the length of the grain boundary having a rotation angle of 4 ° to 12 ° to the total length with the length of the grain boundary to be becomes 15% or more.
  • the ratio of the length of the grain boundaries having a rotation angle of 4 ° to 12 ° is preferably 20% or more.
  • the upper limit of the ratio of the length of the grain boundaries at which the rotation angle is 4 ° to 12 ° may be 50% from the viewpoint of ensuring the strength by strengthening the grain boundaries.
  • the metal structure of the hot stamped molded product according to the present embodiment may be mainly composed of crystal grains having a body-core structure such as martensite, tempered martensite, upper bainite, and lower bainite.
  • the body-centered structure is a general term for a crystal structure such as a body-centered cubic structure or a body-centered cubic structure.
  • the term "mainly" in which the crystal grains are present means that the crystal grains have an area ratio of 80% or more in the metal structure.
  • the remaining structure is one or more of pearlite and ferrite of 20% or less.
  • the EBSD analysis uses an apparatus composed of a thermal field emission scanning electron microscope (JSM-7001F manufactured by JEOL) and an EBSD detector (DVC5 type detector manufactured by TSL), and has an analysis speed of 200 to 300 points / sec.
  • the crystal orientation of the former austenite grains is calculated from the crystal orientation relationship between the general former austenite grains and the crystal grains having a body-centered structure after transformation, and the average crystal of the former austenite grains is calculated.
  • the particle size may be calculated.
  • the method for calculating the crystal orientation of the former austenite grains is not particularly limited.
  • a crystal orientation map of the former austenite grains is prepared by the method described in Non-Patent Document 1, and the former austenite is obtained from the created crystal orientation map by the section method.
  • the average crystal grain size of the grains may be calculated.
  • the length of the grain boundary and the rotation angle at which the rotation angle is 57 ° to 63 ° with the ⁇ 011> direction as the rotation axis are The total length of the grain boundaries with a rotation angle of 49 ° to 56 °, the length of the grain boundaries with a rotation angle of 4 ° to 12 °, and the length of the grain boundaries with a rotation angle of 64 ° to 72 °.
  • the ratio of the lengths of the grain boundaries having a rotation angle of 4 ° to 12 ° is obtained by the following method.
  • the sample has a length that can be observed in the rolling direction by about 10 mm, although it depends on the measuring device.
  • the plate thickness 1/2 position is subjected to EBSD analysis at a measurement interval of 0.1 ⁇ m to obtain crystal orientation information.
  • the EBSD analysis uses an apparatus composed of a thermal field emission scanning electron microscope (JSM-7001F manufactured by JEOL) and an EBSD detector (DVC5 type detector manufactured by TSL), and has an analysis speed of 200 to 300 points / sec. To carry out at.
  • the rotation angle is 57 ° to 57 ° with the ⁇ 011> direction as the rotation axis.
  • the length of the grain boundary of 63 °, the length of the grain boundary of the rotation angle of 49 ° to 56 °, the length of the grain boundary of the rotation angle of 4 ° to 12 °, and the rotation angle of 64 ° to 72 ° The length of the grain boundary is calculated, and the ratio of the length of the grain boundary having the rotation angle of 4 ° to 12 ° is calculated with respect to the total value of the lengths of the respective grain boundaries.
  • the length of the grain boundaries at which the rotation angle is 57 ° to 63 ° with the ⁇ 011> direction as the rotation axis is determined.
  • the length of the above-mentioned grain boundaries can be easily calculated by using, for example, the "Inverse Pole Figure Map” and "Axis Angle” functions installed in the software "OIM Analysis (registered trademark)" attached to the EBSD analyzer. It is possible to do. With these functions, the total length of the grain boundaries of a crystal grain having a body-centered structure can be calculated by designating a specific rotation angle with an arbitrary direction as the rotation axis.
  • the above analysis may be performed on all the crystal grains included in the measurement region, and the lengths of the above-mentioned four types of grain boundaries may be calculated with the ⁇ 011> direction as the rotation axis.
  • a plating layer may be formed on the surface of the hot stamp molded product for the purpose of improving corrosion resistance and the like.
  • the plating layer may be either an electroplating layer or a hot-dip plating layer.
  • the electroplating layer includes, for example, an electrogalvanizing layer, an electric Zn—Ni alloy plating layer, and the like.
  • the hot-dip galvanizing layer includes, for example, a hot-dip galvanizing layer, an alloyed hot-dip galvanizing layer, a hot-dip aluminum plating layer, a hot-dip Zn-Al alloy plating layer, a hot-dip Zn-Al-Mg alloy plating layer, and a hot-dip Zn-Al-Mg-Si. Includes alloy plating layer and the like.
  • the amount of adhesion of the plating layer is not particularly limited and may be a general amount of adhesion.
  • the hot stamp molded product according to the present embodiment may have a softened region partially formed. Weldability is improved in the softened region. For example, if spot welding is performed after softening the end portion of the hot stamp molded body, the strength difference between the softened end portion and the spot welded portion of the end portion can be reduced, so that the strength difference between the two ends can be reduced. Destruction can be suppressed. Further, for example, when a hot stamp molded body is applied to a high-strength member of an automobile, it is possible to control the destruction and deformation modes of the high-strength member at the time of a collision by providing a softening region in a part of the high-strength member. it can.
  • the strength of a part of the hot stamping compact may be reduced by laser irradiation.
  • Laser irradiation is an example of heat treatment which is a softening means, and the softening means is not particularly limited.
  • a softened region may be formed by tempering a part of the hot stamped molded product.
  • a suitable manufacturing method for obtaining the hot stamp molded product according to the present embodiment will be described.
  • a steel piece having the above-mentioned chemical composition is subjected to hot rolling, hot rolling is completed at a temperature of 800 ° C. or higher, and 500.
  • the hot-rolled steel sheet being wound at a temperature of ° C. or higher and 770 ° C. or lower has an average cooling rate of 50 ° C./s or less in the temperature range of 650 ° C. to 400 ° C.
  • the steel piece (steel material) to be used for hot rolling may be a steel piece manufactured by a conventional method, for example, a steel piece manufactured by a general method such as a continuously cast slab or a thin slab caster.
  • the hot rolling end temperature is less than 800 ° C., recrystallization of austenite does not occur and a desired amount of granular bainite may not be obtained. Therefore, the hot rolling end temperature is preferably 800 ° C. or higher. It is preferably 820 ° C. or higher. Further, in the steel having the chemical composition specified in the present embodiment, since recrystallization is unlikely to be over-promoted, the upper limit of the hot rolling end temperature is not particularly specified, but is usually 1050 ° C.
  • the average cooling rate of the hot-rolled steel sheet being wound at a temperature of 500 ° C. or higher and 770 ° C. or lower in the temperature range of 650 ° C. to 400 ° C. is 50 ° C./s or less. It is preferable to start the winding at 500 ° C. or higher and 770 ° C. or lower, and control the average cooling rate of the hot-rolled steel sheet being wound in the temperature range of 650 ° C. to 400 ° C. to 50 ° C./s or less. If the winding is started at a temperature higher than 770 ° C., the transformation from austenite to bainitic ferrite may not occur. Therefore, the winding temperature is preferably 770 ° C. or lower. When the winding temperature is 500 ° C., the formation of granular bainite may not occur. Therefore, the winding temperature is preferably 500 ° C. or higher.
  • the temperature range of the hot-rolled steel sheet being wound from 650 ° C to 400 ° C at an average cooling rate of 50 ° C / s or less.
  • the grain boundaries between bainitic ferrites are restored due to the effect of Ni content to form subgrain boundaries, and a desired amount of granular bainite is formed.
  • a desired amount of granular bainite can be produced.
  • the average cooling rate in the above temperature range exceeds 50 ° C./s, the grain boundaries between bainitic ferrites may be restored and subgrain boundaries may not be formed.
  • the average cooling rate in the above temperature range is preferably 50 ° C./s or less. Since it is preferable that the cooling rate is slower in order to promote the formation of subgrain boundaries, the average cooling rate in the above temperature range is preferably 30 ° C./s or less and 20 ° C./s or less.
  • the lower limit of the average cooling rate in the above temperature range is not particularly limited, but the lower limit is 0.1 ° C./s in normal actual operation.
  • the average cooling rate during winding is calculated by measuring the temperature at the center of the hot-rolled coil during winding in the longitudinal direction using an infrared radiation thermometer for high temperature measurement.
  • the hot-rolled steel sheet wound in the hot-rolling step may be unwound, pickled, and then cold-rolled.
  • the pickling may be performed once or may be divided into a plurality of times.
  • the cold rolling may be cold rolling performed at a normal cumulative reduction rate, for example, a cumulative reduction rate of 30 to 90%, but the cold rolling is not limited to this cumulative reduction rate.
  • hot-rolled steel sheets and cold-rolled steel sheets include hot-rolled steel sheets or cold-rolled steel sheets that have been recrystallized and annealed under normal conditions, and under normal conditions. It also includes steel sheets that have been temper-rolled in.
  • the plating conditions are not particularly limited, and normal conditions may be used.
  • a hot-rolled steel sheet, a cold-rolled steel sheet, or a cold-rolled steel sheet that has been recrystallized and / or temper-rolled may be plated under normal plating conditions, if necessary.
  • examples of plating include electroplating and hot-dip galvanizing
  • examples of electroplating include electroplating and electric Zn—Ni alloy plating
  • examples of hot-dip galvanizing include hot-dip galvanizing, alloyed hot-dip galvanizing, and hot-dip aluminum plating. Examples thereof include hot-dip Zn-Al alloy plating, hot-dip Zn-Al-Mg alloy plating, and hot-dip Zn-Al-Mg-Si alloy plating.
  • the hot stamp After heating to a holding temperature of 800 ° C. or higher at an average heating rate of 100 ° C./s or higher and less than 200 ° C./s, hold the hot stamp so that the elapsed time from the start of heating to molding is 240 seconds or less. Apply and cool to a temperature range of 400 ° C or less.
  • the above-mentioned steel sheet for hot stamping is heated to a temperature of 800 ° C. or higher at an average heating rate of 100 ° C./s or more and less than 200 ° C./s and then held.
  • the holding temperature is preferably 800 ° C. or higher.
  • the holding time may be set so that the elapsed time from the start of heating to the start of molding is within a predetermined range.
  • the hot stamped molded product after hot stamping is preferably cooled by a mold to a temperature range of 400 ° C. or lower.
  • the grain boundaries of martensite can be controlled to a preferable form.
  • the average heating rate up to 800 ° C. or higher to 100 ° C./s or higher, less than 200 ° C./s, and the elapsed time from the start of heating to molding to 240 seconds or lower, the average crystal grain size of the old austenite grains is 10 ⁇ m or lower.
  • the rotation angle is 57 ° to 63 ° with the ⁇ 011> direction as the rotation axis.
  • the ratio of the length of the grain boundary having the rotation angle of 4 ° to 12 ° to the total length of the length can be 15% or more. Therefore, it is preferable that the average heating rate up to 800 ° C. or higher is 100 ° C./s or higher and less than 200 ° C./s, and the elapsed time from the start of heating to molding is 240 seconds or shorter.
  • the hot stamped compact cooled to room temperature may be tempered in the range of 150 ° C. to 650 ° C. for the purpose of adjusting the strength and improving the ductile brittle transition temperature and low temperature toughness.
  • only a part of the hot stamp molded product may be tempered.
  • a softened region can be formed in a part of the hot stamped molded product, and properties such as strength and toughness can be controlled according to the portion of the hot stamped molded product.
  • the conditions in the examples are one condition example adopted for confirming the feasibility and effect of the present invention, and the present invention is not limited to this one condition example.
  • various conditions can be adopted as long as the gist of the present invention is not deviated and the object of the present invention is achieved.
  • Steel pieces produced by casting molten steel having the chemical compositions shown in Tables 1 to 3 are hot-rolled under the conditions shown in Tables 4 to 6, and cold-rolled and / or plated as necessary.
  • the steel sheets for hot stamping shown in 4 to 6 were obtained. Further, the steel sheet for hot stamping is heat-treated under the conditions shown in Tables 7 to 9 for hot stamping, and if necessary, heated to the temperature shown in Table 9 and tempered, or a part of the hot stamped molded product. A softened region was formed by irradiating the mixture with a laser and tempering to obtain a hot stamped molded product shown in Tables 7 to 9.
  • granular baynite (the average crystal orientation difference inside the crystal grains surrounded by the grain boundaries with an average crystal orientation difference of 5 ° or more is 0.4 ° or more and 3.0 ° or less).
  • the ratio of the grain boundary lengths having an average crystal orientation difference of 0.4 ° or more and 3.0 ° or less with respect to the length of the grain boundaries was obtained by the above method.
  • the rotation angle is 57 with the ⁇ 011> direction as the rotation axis among the grain boundaries in which the average crystal grain size of the old austenite grains and the average crystal orientation difference between the crystal grains having a body core structure are 5 ° or more.
  • the Vickers hardness of the hot stamp molded product was obtained by the following method. First, a sample was cut out so that a cross section perpendicular to the surface (thick cross section) could be observed from an arbitrary position 50 mm or more away from the end face of the hot stamp molded body. The size of the sample was set so that it could be observed by 10 mm in the rolling direction, although it depends on the measuring device. The cross section of the sample was polished using # 600 to # 1500 silicon carbide paper, and then mirror-finished using a diluted solution such as alcohol and a liquid in which diamond powder having a particle size of 1 to 6 ⁇ m was dispersed in pure water. ..
  • Tables 7 to 9 show the metallographic structure and mechanical properties of the hot stamped product. Looking at Tables 7 to 9, it can be seen that the hot stamped molded article having a chemical composition and a metal structure within the scope of the present invention has high hardness and excellent bendability. On the other hand, it can be seen that a hot stamped article in which any one or more of the chemical composition and the metal structure deviates from the present invention is inferior in one or more of Vickers hardness and bendability.

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 Sheet Steel (AREA)
  • Heat Treatment Of Articles (AREA)

Abstract

Le corps moulé par estampage à chaud de l'invention présente une composition chimique prédéfinie, et est tel que parmi des joints de grains présentant un diamètre de grain cristallin moyen de grains d'austénite primaire inférieur ou égal à １０μｍ, et une différence d'orientation cristalline moyenne dans des grains cristallins ayant une structure centrée supérieure ou égale à 5°, la proportion de la longueur de joints de grains d'angle de rotation compris entre 4 et 12°, est supérieure ou égale à 15%, par rapport à la longueur de joints de grains d'angle de rotation compris entre ５７ et ６３°, à la longueur de joints de grains d'angle de rotation compris entre ４９ et ５６° et à la longueur de joints de grains d'angle de rotation compris entre ４ et １２°, avec une direction ＜０１１＞ pour axe de rotation.
PCT/JP2020/000630 2019-03-25 2020-01-10 Corps moulé par estampage à chaud WO2020195009A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2021508099A JP7350057B2 (ja) 2019-03-25 2020-01-10 ホットスタンプ成形体

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2019-057145 2019-03-25
JP2019057145 2019-03-25

Publications (1)

Publication Number Publication Date
WO2020195009A1 true WO2020195009A1 (fr) 2020-10-01

Family

ID=72610885

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2020/000630 WO2020195009A1 (fr) 2019-03-25 2020-01-10 Corps moulé par estampage à chaud

Country Status (2)

Country Link
JP (1) JP7350057B2 (fr)
WO (1) WO2020195009A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021141097A1 (fr) * 2020-01-09 2021-07-15 日本製鉄株式会社 Corps moulé par estampage à chaud
JPWO2021141100A1 (fr) * 2020-01-09 2021-07-15
JPWO2021141103A1 (fr) * 2020-01-09 2021-07-15
WO2024190769A1 (fr) * 2023-03-13 2024-09-19 日本製鉄株式会社 Élément en acier, et tôle en acier

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004211197A (ja) * 2002-11-14 2004-07-29 Nippon Steel Corp 熱間成形加工後の硬化能および衝撃特性に優れた鋼板およびその使用方法
JP2005213628A (ja) * 2004-02-02 2005-08-11 Nippon Steel Corp 微細組織を有する鋼材及びその製造方法
JP2008045154A (ja) * 2006-08-11 2008-02-28 Nippon Steel Corp 溶接性、加工性に優れ、高硬度飛翔体に対する耐高速衝突貫通性能に優れる高硬度熱延鋼板およびその製造方法
JP2010215954A (ja) * 2009-03-16 2010-09-30 Sumitomo Metal Ind Ltd 熱間プレス用鋼板およびその製造方法ならびに熱間プレス用鋼板部材の製造方法
JP2012001802A (ja) * 2010-06-21 2012-01-05 Sumitomo Metal Ind Ltd 鋼材およびその製造方法ならびに焼入処理用鋼板
WO2018151333A1 (fr) * 2017-02-20 2018-08-23 新日鐵住金株式会社 Corps moulé par estampage à chaud
WO2018180979A1 (fr) * 2017-03-27 2018-10-04 新日鐵住金株式会社 Tôle d'acier plaquée a base d'al

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2004211197A (ja) * 2002-11-14 2004-07-29 Nippon Steel Corp 熱間成形加工後の硬化能および衝撃特性に優れた鋼板およびその使用方法
JP2005213628A (ja) * 2004-02-02 2005-08-11 Nippon Steel Corp 微細組織を有する鋼材及びその製造方法
JP2008045154A (ja) * 2006-08-11 2008-02-28 Nippon Steel Corp 溶接性、加工性に優れ、高硬度飛翔体に対する耐高速衝突貫通性能に優れる高硬度熱延鋼板およびその製造方法
JP2010215954A (ja) * 2009-03-16 2010-09-30 Sumitomo Metal Ind Ltd 熱間プレス用鋼板およびその製造方法ならびに熱間プレス用鋼板部材の製造方法
JP2012001802A (ja) * 2010-06-21 2012-01-05 Sumitomo Metal Ind Ltd 鋼材およびその製造方法ならびに焼入処理用鋼板
WO2018151333A1 (fr) * 2017-02-20 2018-08-23 新日鐵住金株式会社 Corps moulé par estampage à chaud
WO2018180979A1 (fr) * 2017-03-27 2018-10-04 新日鐵住金株式会社 Tôle d'acier plaquée a base d'al

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2021141097A1 (fr) * 2020-01-09 2021-07-15 日本製鉄株式会社 Corps moulé par estampage à chaud
JPWO2021141100A1 (fr) * 2020-01-09 2021-07-15
WO2021141100A1 (fr) * 2020-01-09 2021-07-15 日本製鉄株式会社 Corps moulé par estampage à chaud
JPWO2021141103A1 (fr) * 2020-01-09 2021-07-15
JPWO2021141097A1 (fr) * 2020-01-09 2021-07-15
WO2021141103A1 (fr) * 2020-01-09 2021-07-15 日本製鉄株式会社 Corps moulé par estampage à chaud
JP7319571B2 (ja) 2020-01-09 2023-08-02 日本製鉄株式会社 ホットスタンプ成形体
JP7319569B2 (ja) 2020-01-09 2023-08-02 日本製鉄株式会社 ホットスタンプ成形体
JP7319570B2 (ja) 2020-01-09 2023-08-02 日本製鉄株式会社 ホットスタンプ成形体
WO2024190769A1 (fr) * 2023-03-13 2024-09-19 日本製鉄株式会社 Élément en acier, et tôle en acier
WO2024190779A1 (fr) * 2023-03-13 2024-09-19 日本製鉄株式会社 Élément en acier, et tôle en acier

Also Published As

Publication number Publication date
JP7350057B2 (ja) 2023-09-25
JPWO2020195009A1 (ja) 2021-11-04

Similar Documents

Publication Publication Date Title
KR102643398B1 (ko) 핫 스탬프 성형체
JP6260676B2 (ja) ホットプレス用鋼板およびその製造方法、ならびにホットプレス部材およびその製造方法
JP6252710B2 (ja) 温間加工用高強度鋼板およびその製造方法
JP7350057B2 (ja) ホットスタンプ成形体
KR20100019443A (ko) 양호한 스탬핑성을 갖는 저밀도 강
KR20120123153A (ko) 열처리 강재와 그 제조 방법 및 그 소재 강재
JP7151871B2 (ja) ホットスタンプ成形体
JP7366121B2 (ja) ホットスタンプ用鋼板
WO2020241258A1 (fr) Corps moule par estampage a chaud
JP2008308732A (ja) 焼入れ鋼板部材および焼入れ用鋼板とそれらの製造方法
JPWO2020203979A1 (ja) 被覆鋼部材、被覆鋼板およびそれらの製造方法
KR20220091572A (ko) 핫 스탬프 성형체
JP6443375B2 (ja) ホットプレス部材およびその製造方法
JP7455112B2 (ja) ホットスタンプ成形体
JP5316025B2 (ja) 熱間打抜き性に優れたダイクエンチ用鋼板
JP2010174293A (ja) 熱間打抜き性に優れたダイクエンチ用鋼板
JP5316028B2 (ja) 熱間打抜き性に優れたダイクエンチ用鋼板
JP6652230B1 (ja) 高強度鋼板
KR20240154043A (ko) 핫 스탬프 성형체
WO2023189174A1 (fr) Article formé par estampage à chaud
JP5316026B2 (ja) 熱間打抜き性に優れたダイクエンチ用鋼板
KR20220147142A (ko) 핫 스탬프용 강판 및 핫 스탬프 성형체
KR20220146646A (ko) 핫 스탬프용 강판 및 핫 스탬프 성형체
JP5316027B2 (ja) 熱間打抜き性に優れたダイクエンチ用鋼板
JP5447776B2 (ja) 熱間打抜き性に優れたダイクエンチ用鋼板

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 20776708

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2021508099

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 20776708

Country of ref document: EP

Kind code of ref document: A1