CHAPA DE AÇO GALVANIZADA PARA ESTAMPAGEM A QUENTE, E, MÉTODO PARA PRODUZIR UMA CHAPA DE AÇO GALVANIZADA PARA ESTAMPAGEM A QUENTE

Abstract

The base steel sheet of this galvanized steel sheet has a component composition that satisfies C: 0.15-0.50 mass%, Si: 0.02-2.5 mass%, Mn: 0.5-5 mass%, P: 0.03 mass% or less (including 0 mass%), S: 0.02 mass% or less (including 0 mass%), Al: 0.010 to 1 mass%, Ti: 0.005-0.080 mass%, and B: 0.0005-0.005 mass%, with the balance being Fe and inevitable impurities. When an element analysis is performed in the thickness direction of the plating layer from the surface of the plating layer by glow discharge optical emission spectrometry (GD-OES), it is found that the carbon concentration [Cf] (mass%) at a position where the concentration of Zn constituting the plating layer is 1.0 mass% and the bulk carbon concentration [Cb] (mass%) satisfy formula (1): [Cf] ≤ 0.65 × [Cb].

Description

[001] The present invention relates to a galvanized steel sheet for hot stamping and a method for its production. FUNDAMENTALS OF THE TECHNIQUE

[002] Conventionally, it is necessary to improve the safety of an occupant in a vehicle, and the strength of the vehicle's body material has to be improved for this purpose. On the other hand, based on the growing problem of global warming and similar issues, the movement to improve the fuel efficiency of automobiles is accelerating. It is known that reducing the weight of a vehicle's body is effective in improving fuel efficiency.

[003] A hot-stamped (hot-formed) steel sheet can easily achieve high strength and processability (shape-freezing capability and the like) with the aim of reducing the weight of a vehicle body, for example. A hot-dip galvanized steel sheet for hot stamping is particularly applied to a part that requires corrosion resistance.

[004] As a hot stamping (hot forming) steel sheet, the following steel sheet has been conventionally proposed. For example, Patent Document 1 describes a steel sheet in which the Ti to N ratio is defined as a hot forming steel sheet, wherein the steel sheet is excellent in the resistance of a joint part at the time of spot welding and can achieve favorable forming without causing breakage, cracking or the like at the time of hot forming. Furthermore, Patent Document 2 describes that, as a hot stamping steel sheet, excellent Petition 870250083662, dated 09 / 17 / 2025, p. 13 / 68 / 48, both in the balance between strength and toughness and in the stability of hardness, high strength is achieved by increasing the ratio of alloying elements, for example, by adjusting the balance of C, Si, Mn and Cr contents.

[005] However, the alloying element ratio of the galvanized steel sheet is increased, easily causing cracking due to liquid metal embrittlement (LME) or liquid metal cracking (LMC) (LME cracking). In particular, hot stamping is performed using a galvanized steel sheet, a component is shaped, then spot welding is performed to assemble the vehicle body, and then LME cracking occurs, which generates a problem of insufficient weld strength in the welded part.For this problem, for example, Patent Document 3 proposes a technique to increase the Fe concentration of a hot-dip galvanized coating bonded to a hot-dip galvanized steel sheet for hot stamping to more than 8.0% by mass and reduce the weight of the coating (amount of Zn: 15.0 to 40.0 g / m2) to avoid time loss in the formation of the Fe-Zn solid solution phase, considering that in a molded car body obtained by hot stamping of a hot-dip galvanized steel sheet, it is necessary to set the heating time in a furnace (furnace time) to about 4 minutes or more to improve weldability and chemical convertibility and suppress LME, and that hot stamping has lower press productivity than cold pressing and therefore it is necessary to shorten the furnace time. Prior Art Documents PATENT DOCUMENTS

[006] Patent Document 1: JP-A-2007-169679 Patent Document 2: JP-A-2019-173158 Patent Document 3: JP-A-2022-131411 NON-PATENT DOCUMENT Petition 870250083662, dated 09 / 17 / 2025, page 14 / 68 / 48

[007] Non-Patent Document 1: “Behavior of Corrosion Tip Portion in Under-Coating Corrosion of Zn-Fe Alloy-Plated Steel Sheet”, Koryo Hayashi et al., Iron and Steel, 76 (1990), No. 9, pp. 1496-1503. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[008] In the technique of Patent Document 3, although it is possible to suppress the LME, the weight of the coating is reduced and therefore the amount of effective zinc that contributes to ensuring the corrosion resistance of the plating is reduced, and it is difficult to present the corrosion resistance improvement effect, which is the original role of plating. Regarding the corrosion resistance of plating, as shown in Non-Patent Document 1, it is known that, in particular, the Fe concentration in the plating exceeds 65% by mass, greatly deteriorating the corrosion resistance. Therefore, it is desirable to achieve both the suppression of LME and the guarantee of corrosion resistance, while at the same time presenting high resistance.The present invention was made in view of the above circumstances, and an object of the present invention is to provide a galvanized steel sheet for hot stamping, wherein the steel sheet exhibits excellent resistance to LME while also ensuring resistance to corrosion inherent in plating, and additionally exhibits high strength (particularly tensile strength of 1.5 GPa or more) after hot stamping, and a method for producing it. SOLUTIONS TO THE PROBLEMS

[009] A first aspect of the present invention is a galvanized steel sheet for hot stamping, WHEREIN a composition of components of a base steel sheet satisfies: C: 0.15 to 0.50% by mass; Si: 0.02 to 2.5% by mass; Mn: 0.5 to 5% by mass; Petition 870250083662, dated 09 / 17 / 2025, p. 15 / 68 / 48 P: 0.03% by mass or less (including 0% by mass); S: 0.02% by mass or less (including 0% by mass); Al: 0.010 to 1% by mass; Ti: 0.005 to 0.080% by mass; and B: 0.0005 to 0.005% by mass, with the remainder being Fe and unavoidable impurities, when elemental analysis is performed in the thickness direction of a plated layer from a plated layer surface by glow discharge optical emission spectrometry (GD-OES), a carbon concentration [Cf] (% by mass) at a position where a Zn concentration constituting the plated layer is 1.0% by mass and a volumetric carbon concentration [Cb] (% by mass) satisfy the following formula (1). [Cf] < 0.65 x [Cb] (1)

[0010] The second aspect of the present invention is the galvanized steel sheet for hot stamping according to the first aspect, wherein a composition of components of the base steel sheet satisfies one or more of the following (a) and (b).

[0011] (a) additionally includes one or more elements selected from the group consisting of: Cr: more than 0% by mass and 1.2% by mass or less; Mo: more than 0% by mass and 1% by mass or less; and Ca: more than 0% by mass and 0.0040% by mass or less.

[0012] (b) additionally includes one or more elements selected from the group consisting of: Nb: more than 0% by mass and 0.040% by mass or less; V: more than 0% by mass and 0.30% by mass or less; Cu: more than 0% by mass and 0.30% by mass or less; Ni: more than 0% by mass and 0.30% by mass or less; Petition 870250083662, dated 09 / 17 / 2025, page 16 / 68 / 48 Mg: more than 0% by mass and 0.010% by mass or less; and REM: more than 0% by mass and 0.010% by mass or less.

[0013] A third aspect of the present invention is a method for producing a galvanized steel sheet for hot stamping, wherein the method includes: an annealing step comprising holding a hot-rolled steel sheet or a cold-rolled steel sheet that satisfies the component composition according to the first or second aspect at 500 to 930°C for 90 to 1,000 seconds in a reducing atmosphere with a dew point of -20°C to +10°C; and a subsequent galvanizing step.

[0014] A fourth aspect of the present invention is the method for producing a galvanized steel sheet for hot stamping according to the third aspect, wherein the galvanizing step is a hot-dip galvanizing step. EFFECTS OF THE INVENTION

[0015] The present invention can provide a high-strength galvanized steel sheet for hot stamping, the steel sheet being excellent in resistance to LME, and a method for producing it. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 shows a view of a steel plate collection position for evaluation in the Example.

[0017] Figure 2 shows a view of the carbon profile of a sample before hot stamping in the Example, where on the left is the carbon profile of the Comparative Example and on the right is the carbon profile of the Example of the present invention.

[0018] Figure 3 shows a SEM photograph of an example of an EDX analysis area of ​​a sample before hot stamping in the Example.

[0019] Figure 4 shows a view of the EDX analysis result. Petition 870250083662, dated 09 / 17 / 2025, p. 17 / 68 / 48 of a sample before hot stamping in the Example.

[0020] Figure 5 shows a view of a hot stamping heating pattern in the Example.

[0021] Figure 6 shows a view of the carbon profile of a sample after hot stamping in the Example, where the carbon profile of the Comparative Example is on the left and the carbon profile of the Example is on the right.

[0022] Figure 7 shows a SEM photograph of an example of an EDX analysis area of ​​a sample after hot stamping in the Example.

[0023] Figure 8 shows a view of the EDX analysis result of a sample after hot stamping in the Example.

[0024] Figure 9 shows a view of the welding test conditions in the Example.

[0025] Figure 10 shows a view depicting a sample collection position for the welding test in the Example.

[0026] Figure 11 shows a view depicting a crack observation location in a sample section after the welding test in the Example.

[0027] Figure 12 shows a view depicting an internal crack and void space after the welding test in the Example. DETAILED DESCRIPTION

[0028] The present inventors have studied intensively to obtain a galvanized steel sheet for hot stamping, which not only exhibits high strength after hot stamping, but is also excellent in resistance to LME, with the premise of forming a galvanized layer to ensure corrosion resistance. First, the present inventors carried out studies and, as a result, it was verified that in a steel sheet for hot stamping, unlike a steel sheet Petition 870250083662, dated 09 / 17 / 2025, page 18 / 68 / 48. In general, cold-rolled steel, heating is carried out during hot stamping, thus causing a phenomenon in which carbon (C) is concentrated at an interface between a plating layer and a base steel (hereinafter referred to as the "plated layer / base steel interface") (as shown in the carbon profile on the left side of Figure 6 described later, the carbon concentration [C] at the plating layer / base steel interface after hot stamping: 0.303% by mass is greater than the volume carbon concentration: 0.220% by mass). Carbon is known as an element that deteriorates LME resistance, and it was first verified that a major factor in the deterioration of the LME resistance of a hot-stamped steel sheet is this carbon concentration phenomenon.

[0029] So, it was verified that in order to suppress the phenomenon of carbon concentration at the plated layer / base steel interface after hot stamping, it is important to suppress the carbon concentration at the plated layer / base steel interface of the galvanized steel sheet to be subjected to hot stamping, specifically, to satisfy the following formula (1). [Cf] < 0.65 x [Cb] (1)

[0030] In formula (1), [Cf] is the carbon concentration (% by mass) at a position where the Zn concentration constituting the plated layer is 1.0% by mass when elemental analysis is performed in the thickness direction of the plated layer from the surface of the plated layer by glow discharge optical emission spectrometry (GD-OES), and [Cb] is the carbon concentration by mass (%).

[0031] In formula (1) above, the “position where the concentration of Zn constituting the plated layer is 1.0% by mass when elemental analysis is performed in the thickness direction of the plated layer from the surface of the plated layer by optical emission spectrometry by Petition 870250083662, dated 09 / 17 / 2025, page 19 / 68 / 48, "glow discharge (GD-OES)" refers to a plated layer / base steel interface in the present embodiment. In other words, the galvanized layer refers to a region where the zinc (Zn) concentration is 1% by mass or more from the surface of the plated layer. Elemental analysis performed in the thickness direction of the plated layer from the surface of the plated layer by glow discharge optical emission spectrometry (GD-OES) is performed by a method shown in the Example.

[0032] Furthermore, the volumetric carbon concentration [Cb] (% by mass) refers to a carbon (C) concentration determined by analyzing a hot-stamped steel sheet with a total sheet thickness of x 50 mm x 50 mm or more by a combustion infrared absorption method. When determining the volumetric carbon concentration, the content of each element in the volume can be analyzed by a conventional method, and is performed by the following method. The amount of Si in the steel sheet produced in the Example described below was greater than 0.7% by mass and therefore the amount of Si was determined by a weight method as described below, but when the amount of Si was 0.7% by mass or less, ICP analysis was recommended. <Método de análise> • Inductively coupled plasma (ICP) atomic emission spectroscopy: Si (when 0.7% by mass or less), Mn, P, Cu, sol-Al, Ni, Cr, Mo, V, Nb, Ti, B, Ca • Flameless atomic absorption spectrophotometry: Sn • Weight method: Si (more than 0.7% by mass) • Combustion infrared absorption method: C, S • Inert gas fusion method-TCD [N], inert gas fusion method-infrared absorption [O]: N, O

[0033] The present inventors have verified that, as shown Petition 870250083662, dated 09 / 17 / 2025, page 20 / 68 / 48 in formula (1) above, in the surface layer region of the galvanized steel sheet before hot stamping, for example, as shown in the carbon profile on the right side of Figure 2 to be described later, the carbon concentration at the plated layer / base steel interface is reduced to [volumetric carbon concentration x 0.65] or less, i.e., by providing a decarburized surface layer, as shown in the carbon profile on the right side of Figure 6 to be described later, the carbon concentration at the plated layer / base steel interface after hot stamping can be suppressed to 0.225% by mass, which is almost the same as the volumetric carbon concentration. As a result, as shown in the Example described later, LME cracking could be suppressed when welding is performed using the galvanized steel sheet.From this, it is considered that the phenomenon of carbon concentration after hot stamping can be suppressed by reducing the carbon in the surface layer region of the galvanized steel sheet before hot stamping, and, as a result, an improved resistance to LME is observed. In the surface layer region of the galvanized steel sheet before hot stamping, the carbon concentration at the plating / base steel interface is preferably 0.60 or less of the volumetric carbon concentration, and more preferably 0.50 or less of the volumetric carbon concentration. From the point of view of improving LME resistance, the ratio relative to the volumetric carbon concentration is preferably lower.Considering the production conditions, the mechanical properties of the steel sheet after hot stamping and similar factors, the lower limit of the ratio between the carbon concentration at the plating / base steel interface and the volumetric carbon concentration can be around 0.01.

[0034] Reducing the carbon concentration at the plating / base steel interface in galvanized steel sheet before stamping Petition 870250083662, dated 09 / 17 / 2025, page 21 / 68 / 48 hot can be obtained by producing the galvanized steel sheet under the conditions described below. [Composition of components]

[0035] The composition of the base steel sheet components (the part excluding the plating layer of the plating sheet) in the galvanized steel sheet for hot stamping of the present embodiment will be described below. In the galvanized steel sheet for hot stamping according to the present embodiment, satisfying the following component composition ensures a resistance of 1.5 GPa or more after hot stamping, and improves component productivity, plating properties, and LME resistance. [C: 0.15 to 0.50% by mass]

[0036] C is an effective element for improving the strength of steel sheet and for achieving a TS strength of 1,470 MPa or more after hot stamping, the amount of C needs to be 0.15% by mass or more. The amount of C is preferably 0.18% by mass or more, more preferably 0.20% by mass or more. In contrast, when the amount of C exceeds 0.50% by mass, high strength is easily achieved, but it leads to problems of excessive strength increase and deterioration of the weldability of an original sheet, such as a hot-rolled steel sheet. Furthermore, C is an element that negatively affects LME resistance. Therefore, the amount of C is 0.50% by mass or less, preferably 0.40% by mass or less, more preferably 0.38% by mass or less, and even more preferably 0.35% by mass or less. [Si: 0.02 to 2.5% by mass]

[0037] Silicon has the effect of suppressing the self-tempering of martensite and is therefore an effective element for improving hardness stability and ensuring productivity during component production. Furthermore, silicon is included in a small quantity. Petition 870250083662, dated 09 / 17 / 2025, page 22 / 68 / 48, thus presenting a suppression effect of non-plating during the production of a steel sheet. To present these effects, the amount of Si is defined as 0.02% by mass or more. The amount of Si is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 0.7% by mass or more. In contrast, when the amount of Si exceeds 2.5% by mass, the Ac3 point increases, which leads to an increase in the heating temperature of the hot stamping during the production of the component. Furthermore, Si is an element that negatively affects LME resistance. The reason for this is unclear, but from the results of the present inventors' studies, it is considered that this occurs because the melting point of the plating is reduced by the solid solution in the plating. From these points of view, the amount of Si is defined as 2.5% by mass or less.The amount of Si is preferably 2.4% by mass or less, and more preferably 2.2% by mass or less. [Mn: 0.5 to 5% by mass]

[0038] Mn is a necessary element to ensure hardenability and achieve a TS: 1,470 MPa or more strength after hot stamping. Therefore, the amount of Mn is defined as 0.5% by mass or more. The amount of Mn is preferably 1.0% by mass or more, more preferably 1.5% by mass or more. In contrast, an excessive amount of Mn leads to excessive strength of an original sheet, such as a hot-rolled steel sheet. Furthermore, Mn is an element that deteriorates strength at LME. Therefore, the amount of Mn is defined as 5% by mass or less. The amount of Mn is preferably 4.5% by mass or less, and more preferably 4.0% by mass or less. [P: 0.03% by mass or less (including 0% by mass)]

[0039] P is an element inevitably present as an element of Petition 870250083662, dated 09 / 17 / 2025, p. 23 / 68 / 48 impurity. P negatively affects toughness and retards fracture resistance. Therefore, P is preferably small, and the P content is 0.03% by mass or less, preferably 0.010% by mass or less. In this descriptive report, “including 0% by mass” means including an embodiment in which impurities are not intentionally added, i.e., a case in which the content is equal to or less than the unavoidable level of impurities (the case in which impurities are intentionally added is not excluded). [S: 0.02% by mass or less (including 0% by mass)]

[0040] S is an element inevitably present as an impurity element. S negatively affects toughness and retards fracture resistance. Therefore, the amount of S is preferably small, and the S content is 0.02% by mass or less, preferably 0.010% by mass or less, and most preferably 0.005% by mass or less. [Al: 0.010 to 1% by mass]

[0041] Al is an element that acts as a deoxidizer. To exhibit this effect, the Al content is defined as 0.010% by mass or more. The Al content is preferably 0.015% by mass or more. In contrast, when Al is included in excess in the steel sheet, the hardness after mold cooling decreases. Furthermore, excessive Al2O3 generation deteriorates toughness at low temperatures. Therefore, the Al content is defined as 1% by mass or less. The Al content is preferably 0.8% by mass or less, and more preferably 0.1% by mass or less. The Al content in this document means the Al content (sol. Al) in a solid solution state. [Ti: 0.005 to 0.080% by mass]

[0042] Ti exerts the effect of B described later and therefore has the effect of precipitating N which negatively affects the solid solution of B with Ti and detoxifies N. In addition, Ti has the effect of increasing the amount of B in the solid solution and improving the crack resistance of Petition 870250083662, dated 09 / 17 / 2025, p. 24 / 68 / 48 LME because it is contained together with B. To exhibit these effects, the amount of Ti is 0.005% by mass or more. The amount of Ti is preferably 0.010% by mass or more, more preferably 0.015% by mass or more, and even more preferably 0.020% by mass or more. In contrast, when the amount of Ti is excessive, carbide precipitation, grain refinement, and the like occur; the strength of the original sheet, such as a hot-rolled steel sheet, is increased more than necessary, and processability is deteriorated, which negatively affects economic efficiency. Therefore, the amount of Ti is 0.080% by mass or less. The amount of Ti is preferably 0.070% by mass or less, and more preferably 0.060% by mass or less. [B: 0.0005 to 0.005% by mass]

[0043] B is a necessary element to ensure hardenability and achieve a TS: 1,470 MPa strength or more after hot stamping. Furthermore, it has an effect of improving the LME crack resistance of the welded part at the time of welding. The reason for this effect is unknown, but it is considered, from the results of the present inventors' study, that there is a strengthening effect on the old γ grain boundary, which is a starting point for cracking. To exhibit these effects, the amount of B needs to be 0.0005% by mass or more. The amount of B is preferably 0.0010% by mass or more, and more preferably 0.0015% by mass or more. In contrast, when the amount of B is excessive, the strength of the original sheet, such as a hot-rolled steel sheet, increases more than necessary, and processability deteriorates, negatively affecting economic efficiency.Therefore, the quantity of B is 0.005% by mass or less. The quantity of B is preferably 0.004% by mass or less, and more preferably 0.003% by mass or less.

[0044] Galvanized steel sheet according to the modality of Petition 870250083662, dated 09 / 17 / 2025, page 25 / 68 / 48. The present invention includes the component composition described above and, in one embodiment of the present invention, the remainder is preferably iron and unavoidable impurities. Unavoidable impurities are permitted to include contamination from elements brought in depending on the situation of the raw materials, materials, production facilities, and the like. N is also an unavoidable element present as an impurity element and may be included, for example, in a range of 0.0100% by mass or less (including 0% by mass). For example, as in P and S, the content is preferably lower and, therefore, despite being an unavoidable impurity, there are elements that are specified separately for the composition range as described above. Thus, in the present description, “unavoidable impurities” constituting the remainder means the concept that excludes elements whose composition ranges are defined.

[0045] The composition of steel sheet components in the present embodiment may not include the elements described below. Any other element may be included, provided that the desired properties can be maintained. The inclusion of the elements described below as necessary allows, for example, improved resistance to delayed cracking and further improved resistance to LME.

[0046] [(a) In addition, one or more types of elements selected from the group consisting of: Cr: more than 0% by mass and 1.2% by mass or less; Mo: more than 0% by mass and 1% by mass or less; and Ca: more than 0% by mass and 0.0040% by mass or less.]

[0047] Cr is an element capable of further improving the crack resistance of LME, while also ensuring hardenability. To achieve this effect, the Cr content is preferably greater than 0% by mass, and more preferably 0.05% by mass or more. In contrast, when the amount of Cr is excessive, the pickling and similar properties are affected. Petition 870250083662, dated 09 / 17 / 2025, p. 26 / 68 / 48 necessary in the production stage deteriorate. Furthermore, the strength of the original sheet, such as a hot-rolled steel sheet, is increased more than necessary. Therefore, the amount of Cr is preferably 1.2% by mass or less, and more preferably 1.0% by mass or less.

[0048] Mo has the effect of promoting B diffusion and suppressing sensitivity to LME. From the point of view of exerting the effect, the Mo content is preferably greater than 0% by mass and, more preferably, 0.05% by mass or more. In contrast, when the Mo content is excessive, the strength of the original sheet, such as a hot-rolled steel sheet, increases more than necessary, and processability deteriorates, which negatively affects economic efficiency. Therefore, the Mo content is preferably 1% by mass or less.

[0049] Calcium is an element that suppresses the generation of MnS, which negatively affects delayed fracture resistance, and improves delayed fracture resistance. From the point of view of exerting the effect, the calcium content is preferably greater than 0% by mass, and more preferably 0.001% by mass or more. In contrast, when the amount of calcium is excessive, the effect is saturated, which negatively affects economic efficiency, such as an increase in cost. Therefore, the calcium content is defined as 0.0040% by mass or less.

[0050] [(b) One or more types of elements selected from the group consisting of: Nb: more than 0% by mass and 0.040% by mass or less; V: more than 0% by mass and 0.30% by mass or less; Cu: more than 0% by mass and 0.30% by mass or less; Ni: more than 0% by mass and 0.30% by mass or less; Mg: more than 0% by mass and 0.010% by mass or less; and REM: more than 0% by mass and 0.010% by mass or less.

[0051] Nb forms fine carbides, making the steel structure fine by Petition 870250083662, dated 09 / 17 / 2025, page 27 / 68 / 48 a pinning effect and contributes to improved strength and toughness. To exhibit the effect, the Nb content is preferably greater than 0% by mass, and more preferably 0.0008% by mass or more. In contrast, when Nb is excessively included in the steel plate, coarse carbides are formed, and this serves as a starting point for fracture, leading to deterioration of toughness. Therefore, the Nb content is preferably 0.040% by mass or less.

[0052] V forms fine carbides, thins the steel structure through a pinning effect, and contributes to improved strength and toughness. Furthermore, precipitation occurs during tempering, thus exerting a secondary effect. To exhibit these effects, the V content is preferably greater than 0% by mass, and more preferably 0.008% by mass or more. In contrast, when V is included excessively in the steel sheet, coarse carbides are formed, and this serves as a starting point for fracture, leading to deterioration of toughness. Therefore, the V content is preferably 0.30% by mass or less.

[0053] Cu and Ni are effective elements for improving the delayed fracture resistance of the element and may be included in an amount greater than 0% by mass, as needed. In contrast, excess Cu and Ni included in the steel plate may cause surface failures in the steel plate and eventually in the surface of the element. Therefore, for Cu and Ni, the respective content is preferably 0.30% by mass or less, and the total content is more preferably 0.50% by mass or less.

[0054] Mg and REM may be contained as needed due to their function of micronizing inclusions in the steel sheet and preventing cracking during hot forming due to inclusions. When contained, the content of each element is preferably greater than 0% by mass, and more preferably 0.0008% by mass or more. In contrast, when these elements are included in excess, the effect becomes saturated, leading to an increase in cost. Petition 870250083662, dated 09 / 17 / 2025, page 28 / 68 / 48 Therefore, the content of any element is preferably 0.010% by mass or less, and more preferably 0.008% by mass or less. REM means including lanthanide elements (15 elements from La to Lu), Sc (scandium) and Y (yttrium).

[0055] The type of zinc-based plating on hot-stamped galvanized steel sheet according to the present embodiment is not limited. Examples include Fe-Zn plating and Al-Zn plating. The Fe concentration in the plating layer of the hot-stamped galvanized steel sheet according to the present embodiment is preferably 40% by mass or less, and more preferably 30% by mass or less. Specific examples of galvanized steel sheets include hot-dip galvanized (HDG) steel sheets, hot-dip galvanized alloy (HDG) steel sheets, and electrogalvanized (EG) steel sheets.

[0056] The amount of zinc-based plating coating (in particular hot-dip galvanizing, bonded hot-dip galvanizing) of the galvanized steel sheet for hot stamping according to the present embodiment is preferably 45 g / m2 or more, more preferably 60 g / m2 or more, even more preferably greater than 65 g / m2 from the point of view of ensuring corrosion resistance. In contrast, from the point of view of easily achieving the recommended Fe concentration in the plating layer, the weight of the galvanizing coating is preferably small. Therefore, the weight of the zinc-based plating coating is preferably 190 g / m2 or less, and more preferably 180 g / m2 or less.

[0057] The concentration of Fe in the zinc-based plating of galvanized steel sheet subjected to hot stamping by a method described in the Example described later using galvanized steel sheet for hot stamping according to the present embodiment. Petition 870250083662, dated 17 / 09 / 2025, p. 29 / 68 / 48, is preferably 65% ​​by mass or less, and more preferably 60% by mass or less. The Fe concentration may be 20% by mass or more from the point of view of increasing the Fe concentration in hot stamping plating.

[0058] The present embodiment can improve LME resistance by satisfying the predetermined component composition and providing the predetermined decarburized surface layer, as described above, without reducing the coating weight or increasing the Fe concentration in the hot-dip galvanized layer. [Method for producing galvanized steel sheet for hot stamping]

[0059] Next, a method for producing galvanized steel sheet for hot stamping according to the present embodiment will be described.

[0060] The method for producing a galvanized steel sheet for hot stamping according to the present embodiment includes an annealing step which involves allowing a hot-rolled steel sheet or a cold-rolled steel sheet that meets the component composition to be held at 500 to 930°C for 90 to 1,000 seconds in a reducing atmosphere with a dew point of -20°C to +10°C, and a subsequent galvanizing step.

[0061] First, an annealing step and a subsequent galvanizing step, which are characteristic of the production method according to the present embodiment, will be described. Next, an aspect in which the annealing step according to the present embodiment and the subsequent galvanizing step (particularly, the hot-dip galvanizing step) are carried out in a hot-dip galvanizing line of a reduction furnace system will be described as an example, but is not limited to it. The method according to the present embodiment is not intended to be limited to the above aspect and, for example, the step of Petition 870250083662, dated 09 / 17 / 2025, page 30 / 68 / 48 hot-dip galvanizing can be performed by a continuous annealing line of a non-oxidizing furnace system. (Annealing stage)

[0062] The annealing stage of the hot-dip galvanizing line typically includes a reducing furnace and a cooling range. The present embodiment is distinguished by the fact that the annealing conditions in the reducing furnace, particularly the dew point of the reducing atmosphere, are appropriately controlled. The original sheet is loaded into a reducing furnace. The original sheet to be loaded into the reducing furnace may be subjected to a pre-treatment stage described later, such as degreasing, as needed. In addition, the original sheet to be loaded into the reducing furnace may be subjected to an oxidation treatment by being loaded into an oxidizing furnace as needed after undergoing a pre-treatment stage.

[0063] In the reducing furnace, the original sheet is subjected to heat treatment in a reducing atmosphere. The dew point of the reducing atmosphere is defined as -20°C to +10°C. Setting the dew point within this range causes decarburization of the surface layer of the steel sheet, allowing the desired surface layer region to be obtained. The dew point of the reducing atmosphere is preferably -15°C or lower, and more preferably -10°C or lower. In addition, the dew point of the reducing atmosphere is preferably +5°C or lower, and more preferably 0°C or lower.

[0064] The dew point can be controlled, for example, by a method in which a water vapor gas is charged and mixed with an atmospheric gas in a furnace, or a method in which an atmospheric gas is bubbled through and water vapor is mixed in. The reducing atmosphere is not particularly limited, provided it satisfies the above dew point and is reducing. The reducing atmosphere satisfies the above dew point and, therefore Petition 870250083662, dated 09 / 17 / 2025, page 31 / 68 / 48 example, the concentration of H2 is preferably 1 to 30% by volume in the H2-N2 mixed gas.

[0065] Furthermore, the annealing temperature is defined as 500 to 930°C, and the holding time at the annealing temperature, i.e., the annealing time, is defined as 90 to 1,000 seconds. The annealing treatment in the above temperature range is also called soaking treatment, and in this case, the annealing temperature is called the soaking temperature and the annealing time is called the soaking time.

[0066] The annealing temperature is preferably 530°C or more, more preferably 560°C or more, and even more preferably 600°C or more. The annealing temperature is preferably 900°C or less, and even more preferably 870°C or less. The annealing time is preferably 100 seconds or more, and even more preferably 120 seconds or more. The annealing time is preferably 900 seconds or less, more preferably 700 seconds or less, even more preferably 500 seconds or less, even more preferably 400 seconds or less, and even more preferably 350 seconds or less. The annealing time can be controlled by the speed at which the original sheet passes through the reduction furnace (hereinafter also called “line speed” or “LS” for short). "Being held at 500 to 930°C for 90 to 1,000 seconds" means that it can be held in the annealing temperature range of 500 to 930°C for 90 to 1,000 seconds.000 seconds, and the temperature can be constant or it can vary within the annealing temperature range.

[0067] According to the production method according to the present embodiment, a predetermined surface decarburized layer can be provided by particularly performing annealing on a hot-rolled steel sheet or a cold-rolled steel sheet. Petition 870250083662, dated 09 / 17 / 2025, page 32 / 68 / 48, requesting that it be an original plate with the component composition described above.

[0068] A pre-treatment step of the original sheet that can be carried out before the annealing step will be described. The pre-treatment is normally carried out to remove oil (oil and grease) and dirt adhering to the surface of the original sheet, and is usually an alkaline degreasing. The alkali included in the degreasing liquid used for alkaline degreasing is not particularly limited, provided that it is preferably, for example, caustic soda, a silicate or a mixture thereof, and can remove oil and grease like a water-soluble soap. In addition, to improve the degreasing properties, electrolytic washing, scrubbing treatment and treatment by adding a surfactant or a chelating agent to the degreasing liquid can be carried out.In this embodiment, the pre-treatment method is not limited, provided that the surface of the original sheet is adequately degreased, and the treatments described above can be carried out individually or in any combination.

[0069] The original sheet that came out of the reducing furnace can be cooled in a cooling range. The cooling range may include a slow cooling range, a fast cooling range, and an adjustment range. The adjustment range is also called the holding range. Cooling can be carried out under conditions normally used to avoid plating, and examples of this include a method for cooling the steel sheet by spraying a gas in a reducing atmosphere onto the steel sheet.

[0070] The hot-dip galvanizing line of the reduction furnace system can generally be divided into a pre-treatment stage, an annealing stage, and a plating stage. In the plating stage, an alloy treatment is also carried out, as needed. Petition 870250083662, dated 09 / 17 / 2025, page 33 / 68 / 48

[0071] From an energy saving point of view, the original pre-treated sheet can be preheated in a preheating furnace in a reducing or oxidizing atmosphere using exhaust gases after the pretreatment step and before entering the reducing furnace. (Galvanizing stage)

[0072] After the annealing stage (continuous annealing stage), a galvanizing stage is included. A hot-dip galvanizing stage will be described below as an example of the galvanizing stage. A hot-dip galvanized (HDG) steel sheet is manufactured by a hot-dip galvanizing stage. Alternatively, the HDG can be bonded to manufacture a bonded hot-dip galvanized (HDG) steel sheet.

[0073] The hot-dip galvanizing step is not particularly limited, and a commonly used method can be adopted. For example, the temperature of the hot-dip galvanizing bath can be controlled to about 430 to 500°C. The weight of the hot-dip galvanized coating layer (the same as the weight of the subsequent bonded hot-dip galvanized coating layer) is preferably 45 g / m2 or more, more preferably 60 g / m2 or more, and even more preferably greater than 65 g / m2, from the point of view of guaranteeing corrosion resistance. In contrast, from the point of view of easily achieving the recommended Fe concentration in the plated layer, the weight of the hot-dip galvanized coating layer (particularly the bonded hot-dip galvanized layer) is preferably small.Therefore, the weight of the hot-dip galvanized coating layer is preferably 190 g / m2 or less, more preferably 180 g / m2 or less.

[0074] Alloy treatment is also not particularly limited, and a commonly used method can be adopted. In alloy treatment, Petition 870250083662, dated 17 / 09 / 2025, p. 34 / 68 / 48 when the Fe concentration in the plating layer is increased, the alloy temperature is controlled to, for example, about 400 to 700°C. The alloy temperature is additionally 430°C or more, additionally 440°C or more, and additionally 450°C or more. In contrast, when the alloy temperature is too high, the Fe concentration in the plating layer becomes too high, and therefore the alloy temperature is preferably 680°C or less, and more preferably 650°C or less.

[0075] The step after the plating step is also not particularly limited, and a commonly used method can be adopted. Normally, cold rolling treatments, stress leveling treatments, oil coating and the like are carried out, but these can be performed under the conditions normally used when necessary and may not be performed when unnecessary. The galvanized steel sheet (GI or GA) thus obtained is suitablely used as steel sheet for hot stamping.

[0076] Electroplating can be performed instead of hot-dip galvanizing. For example, the original sheet can be subjected to the annealing described above, and then electroplating can be performed to provide an electrogalvanized steel sheet with a plated layer / base steel interface defined in this embodiment. (Other steps)

[0077] The production method according to the present embodiment may include the prescribed annealing step and the subsequent galvanizing step, and the other steps are not limited and may include a step that is normally performed. Therefore, the method for producing hot-rolled steel sheet or cold-rolled steel sheet to be subjected to the annealing step is not limited and, for example, hot-rolled steel sheet or cold-rolled steel sheet may be produced as follows. First, a plate is produced. In the plate production step, the steel Petition 870250083662, dated 09 / 17 / 2025, page 35 / 68 / 48, is cast according to a conventional method, and the molten steel is poured into a mold and continuously melted to provide a plate. In this step, the composition of steel components is adjusted during melting to satisfy the component range above. A heating step may be provided after casting and before hot rolling to prevent cracking from hot rolling (this step is different from the plate heating step in the subsequent hot rolling step). The heating conditions are not particularly limited, and the conditions normally used may be appropriately adopted, but it is desirable to carry out the heating at a temperature of about 1,100°C to 1,300°C.

[0078] Next, hot rolling is carried out. In the hot rolling stage, first, the plate is placed in a heating furnace, heated to a predetermined temperature (approximately 1,100°C to 1,300°C, for example 1,200°C) and held at the heating temperature for a predetermined time (for example, 30 minutes).

[0079] Next, the plate in a heated state is placed upstream of the hot rolling line, and the plate is rolled into a steel sheet with a predetermined sheet thickness, passing the plate sequentially between the rolls of the roughing mill and the finishing mill in the downstream direction. The steel sheet after hot rolling is cooled to a predetermined temperature by a cooling device and then wound by a coiler.

[0080] Hot-rolled steel sheet can be a pickled hot-rolled steel sheet that is subsequently pickled in a pickling step. In the pickling step, at least the hot-rolling fouling can be removed by pickling. The pickled hot-rolled steel sheet can be cold-rolled as needed. In the cold-rolling step, the hot-rolled steel sheet is rolled further to further reduce the sheet thickness. Specifically, the steel sheet Petition 870250083662, dated 09 / 17 / 2025, page 36 / 68 / 48. Hot-rolled steel sheet, after pickling, is passed between rolls of a rolling mill, further thinning the hot-rolled steel sheet. Cold-rolled steel sheet is particularly suitable for use in automotive components intended for weight reduction in automobiles and similar vehicles. The base steel sheet that constitutes the galvanized steel sheet is desirably a cold-rolled steel sheet from the point of view of dimensional accuracy and flatness. Hot-rolled steel sheet (including pickled hot-rolled steel sheet) or cold-rolled steel sheet (hereinafter, these are collectively referred to as "original sheets") may be subjected to an annealing step and a galvanizing step, for example, a continuous plating step of the reduction furnace type. [Example]

[0081] The present invention will now be described more specifically with reference to the Examples. The present invention is not limited to the following examples and may be implemented with appropriate modifications within the scope that may be consistent with the essence described above and below, and all of which are included in the technical scope of the present invention.

[0082] Steel materials with component compositions shown in Table 1 were melted in a converter and then slabs were produced by continuous casting. The resulting slab was heated to a temperature of 1100°C to 1300°C and then hot-rolled under FDT conditions: 890°C to 950°C and a coiling temperature of 500°C to 700°C, then descaled in a pickling step and cold-rolled to provide a cold-rolled steel sheet. The cold rolling rate at the time of cold rolling was 20% or more. The resulting cold-rolled steel sheet had a thickness of 1.2 mm. In the present Example, a plated steel sheet was produced using the cold-rolled steel sheet as the original sheet. In Table 1, the values Petition 870250083662, dated 09 / 17 / 2025, p. 37 / 68 / 48. Underlined numbers indicate that they are outside the range defined in this modality. The same applies to the following table. Type 2 steel in Table 1 is a type of steel from the Comparative Example because the carbon (C) content is very low. Petition 870250083662, dated 09 / 17 / 2025, pp. 38 / 68 / 48 [Table 1] from page 39 / 68 / 48

[0083] The cold-rolled steel sheet obtained was subjected to reduction annealing in a hot-dip galvanizing annealing line under the conditions (soaking temperature (annealing temperature), soaking time (annealing time), dew point) described in Table 2. In Experiments No. 1 to 7, after immersion in a plating bath, the alloying was performed under the conditions described in Table 2 (alloying temperature and alloying time) to provide a hot-dip galvanized alloyed steel sheet (GA steel sheet) with a width of approximately 1,000 mm and with both surfaces of the steel sheet subjected to hot-dip galvanizing alloy. The GA steel sheet is also a hot-stamping steel sheet. The GA steel sheet can be called a “steel sheet before hot stamping”.Furthermore, in Experiments 8 to 10, plating annealing (decarburization) was performed using a small sample of 150 mm x 80 mm. In this small sample, it was separately confirmed that the decarburized state, strength, and similar properties are equivalent to those of the steel plate. In Experiments 8 to 10, the coating weight was not measured. The annealed material under the same conditions was separately evaluated as being 180 g / m², therefore, an equivalent coating weight (weight per unit area) is also assumed in Experiments 8 to 10 and is shown as 180 g / m² in Table 2. [Table 2] Experiment No. Steel Type Sheet Thickness (mm) Annealing Step Hot-Dip Galvanizing Coating Weight (g / m2) Soaking Temperature (°C) Soaking Time (s) Dew Point (°C) Alloy Temperature (°C) Alloy Time (s) 1 1 1.2 720 138 -7 500 to 650 15 120 2 1 1.2 635 138 -7 500 to 650 15 120 3 1 1.2 700 138 -7 500 to 650 15 120 4 1 1.2 652 166 -30 500 to 650 18 113 5 1 1.2 652 166 -30 500 to 650 18 113 6 2 1.2 675 167 -30 500 to 650 17 69 7 2 1.2 666 197 -30 500 to 650 23 87 8 3 1.2 870 347 -10 550 20 180 * 9 4 1.2 870 347 -10 550 20 180 * 10 4 1.2 870 347 -40 550 20 180 * *1 Although no measurement was made, the evaluation of an annealed material under the same conditions resulted in 180 g / m2e, therefore 180 g / m2 is described because an equivalent basis weight is assumed. Petition 870250083662, dated 09 / 17 / 2025, pp. 40 / 68 / 48

[0084] In Experiments No. 1 to 7, with regard to the steel plate GA, steel plates for evaluation with dimensions of 150 mm L x 70 mm W or 220 mm L x 150 mm W were collected from each position of the central part (range from L / 4 to 3L / 4 in the width direction) ae and the end part (region of the furthest end) b in Figure 1. The collection position of the steel plate for evaluation in each example is shown in Table 5. Furthermore, in experiments 8 to 10, the small sample obtained (size: 150 mm L x 80 mm W) was used without being cut.

[0085] Using each steel sheet for evaluation, the decarburized state of the steel sheet surface layer before hot stamping and the Fe concentration in the plated layer were measured as follows. [Measurement of the decarburized state of the surface layer (before hot stamping) (carbon profile measurement by GD-OES)]

[0086] As described below, the carbon profile was measured by glow discharge optical emission spectrometry (GD-OES), and the decarburization behavior was examined. (Sample preparation)

[0087] Samples measuring 50 mm x 40 mm x 1.2 mm sheet thickness (total sheet thickness), 30 mm x 30 mm x 1.2 mm sheet thickness (total sheet thickness), or 30 mm x 40 mm x 1.2 mm sheet thickness (total sheet thickness) were collected. Degreasing was then performed according to a conventional method to prepare a sample. Then, using the sample, the mass % concentration of each element was measured by GD-OES under the following conditions. (Measurement conditions)

[0088] Device used: Markus High Frequency Glow Discharge Optical Emission Surface Analyzer (rf-GD-OES) GD-Profiler2 manufactured by HORIBA, Ltd. Petition 870250083662, dated 09 / 17 / 2025, pages 41 / 68 / 48

[0089] Sputtering method: normal sputtering

[0090] Measuring range: φ4 mm

[0091] Gas type: Air

[0092] Element to be analyzed: B, C, O, Al, Si, Ti, Cr, Mn, Fe, Zn, P, S and N (in this example, these elements were evaluated, but when elements other than those above are contained, for example, in a plated layer or a steel sheet, elements other than those above should also be analyzed). (Measurement method)

[0093] The surface of the sample on which the plating was formed was subjected to GD-OES measurement until the depth reached 150 μm in the thickness direction of the plate. (Analysis method)

[0094] The cathodic sputtering rate of the present device was substantially constant and therefore the depth of the cathodic sputtering crater of the sample after analysis was measured, and the horizontal geometric axis was taken as the value (cathodic sputtering depth).

[0095] Details of the calibration curve method for converting the measured emission intensity of each element into a concentration will be described below.

[0096] The relationship between the cathodic sputter weight Wi (g / s) per unit time of the element iea and the emission intensity Ii is represented by the following formula (I) using the slope aea and intercept b of the calibration curve. Wi = aIi + b Formula (I)

[0097] The sputtering weight Wi per unit time of element i is determined by the following formula (II) using the area of Petition 870250083662, dated 09 / 17 / 2025, page 42 / 68 / 48 cathodic sputtering S (cm2) in the reference sample in which the concentration Ci (% by weight), the density ρ (g / cm3) and the cathodic sputtering rate Δd (cm / s) are known. Wi = Ci x ρ x Δd x S Formula (II)

[0098] The emission intensity Ii was measured using two or more types of reference samples in which Wi was known, and the slope a and intercept b of the above formula (I) were obtained to prepare a calibration curve in which the horizontal geometric axis was the emission intensity and the vertical geometric axis was the sputter weight. The reference samples used are shown in Table 3 below. Using the prepared calibration curve, the sputter weight was determined from the emission intensity of each target element, and the weight ratio was converted to concentration. The calibration curve used for the O concentration conversion was corrected using SiÜ2 so that the concentration ratio between Si and O was 1:2. [Table 3] Reference sample Main component BCO Al Si Ti Cr Mn Fe Zn BAS 113 Fe 0.0066 0.837 - 0.0151 0.931 0.039 1.248 1.207 94.99 - BAS 114 Fe 0.0008 0.403 - 0.078 0.295 0.0096 0.187 0.416 96.47 - MBH 13X NSD1 Fe - 0.046 - 0.013 0.411 - 24.51 23.53 49.09 - MBH 13X 8110L Fe (1.09) 0.792 - 0.009 0.96 0.055 12.33 0.772 76.08 - MBH 31X BIB3 Cu - - - 0.0298 0.061 - - 0.243 0.099 32.46 SPEX 185-CO2 Cu - - - - - - - - 0.096 0.15 JAPAN FINE CERAMICS CO., LTD. Al2O3 O - - 47.07 (52.93) - - - - - - * The numerical value indicated in parentheses in the table was excluded from the reference value used for concentration conversion.

[0099] Based on the results of the above analysis, zinc and carbon profiles were obtained, which are the results of zinc and carbon analyses. Then, from the zinc and carbon profiles, the concentration was determined. Petition 870250083662, dated 09 / 17 / 2025, page 43 / 68 / 48 of carbon [Cf] at the position where the concentration of Zn constituting the plated layer was 1.0% by mass. The volumetric concentration of C [Cb] was determined by analysis as described above. Then, the value of [Cf] / [Cb] was obtained. These results are shown in Table 5.

[00100] Furthermore, as an example of the carbon profile, as a comparative example, a carbon profile from Experiment No. 4, which is a conventional steel, is shown on the left of Figure 2, and a carbon profile from Experiment No. 1, which is an example of the present invention, is shown on the right of Figure 2. From the comparison of these carbon profiles, it can be seen that, in the present example of the invention, the carbon concentration at the interface between the plated layer and the base steel sheet is sufficiently suppressed.

[00101] In Experiment No. 6, the C concentration at the base steel / plating interface was not evaluated. However, the component composition is the same as in Experiment No. 7 and the reduction annealing conditions are similar to those of Experiment No. 7, and therefore, the C concentration at the base steel / plating interface is considered to be similar to that of Experiment No. 7. Therefore, the C concentration at the base steel / plating interface of No. 6 is estimated at approximately 0.070, which is the same as in Experiment No. 7, and therefore, the values ​​are described in Table 5. [Measurement of Fe concentration in the plated layer (before hot stamping)]

[00102] A 20 mm L x 10 mm W x sheet thickness sample was cut and collected from the GA steel sheet (steel sheet before hot stamping). Degreasing was performed as needed. <Preparation of the observation sample>

[00103] A section in the L direction, that is, a surface formed by the thickness of the sheet and 10 mm L as a side, was embedded in a resin to be an observation surface, polished and then subjected to the deposition of Petition 870250083662, dated 09 / 17 / 2025, page 44 / 68 / 48 gold. <Observação por SEM>

[00104] SEM observation and EDX analysis were performed under the following conditions. In this example, the observation magnification is set to 1,500 times, but the observation magnification depends on the plating weight and therefore it is preferable to select an appropriate magnification for measuring Fe concentration, for example, by decreasing the measurement magnification as the plating thickness increases. (SEM observation conditions)

[00105] • Instrument: Supra-35 field emission scanning electron microscope (FE-SEM) manufactured by Carl Zeiss AG • Observation image: reflected electron image • Observation point: near the surface layer, including the plated layer • Observation magnification: 1,500 times • Number of observation fields: one field of view representing the sample / one sample<Análise por EDX> • Equipment: X-max80 energy dispersive X-ray (EDX) detector manufactured by Oxford Instruments plc • Analysis method: area analysis (semi-quantitative qualitative analysis) • Analysis position: the entire plated layer; an example of an analysis area is shown in Figure 3 • Number of analysis fields: one field of view representing the sample / one sample • Analytical element: among the elements detected by EDX, the mass percentage, which is the ratio of Fe evaluated when elements other than C are taken as a population, was taken as the Petition 870250083662, dated 09 / 17 / 2025, page 45 / 68 / 48 concentration of Fe (%). As an example, the result of the analysis of Experiment No. 4 is shown in Figure 4. Furthermore, as an example, the results of the calculation of the Fe concentration (12.0% by mass) of Experiment No. 4 are shown in Table 4. The Fe concentration in the plated layer of each example obtained by calculation in the same manner as in Table 4 below is shown in Table 5. [Table 4]___________________________________________________________ Element % by mass % by mass excluding C 8.7 0.0 O 1.16 1.3 Al 0.32 0.4 Mn 0.32 0.4 Fe 10.93 12.0 Zn 78.57 86.1 Total 100 100.0 % by mass excluding C 91.3 [Table 5] Experiment No. Position of steel sheet collection Plating state before hot stamping Fe concentration in the plating layer (% by mass) Plating type C concentration at the base steel / plating interface [Cf] (% by mass) Volumetric C concentration [Cb] (% by mass) [Cf] / [Cb] 1 Center 8.8 GA 0.055 0.22 0.25 2 Center 10.2 GA 0.045 0.22 0.21 3 Center 9.9 GA 0.056 0.22 0.26 4 Center 12.0 GA 0.146 0.22 0.67 5 End 8.6 GA 0.211 0.22 0.96 6 Center 17 GA 0.070 *2 0.085 0.82 7 Center 16 GA 0.070 0.085 0.82 8 Small sample 8.8 GA 0.111 0.355 0.31 9 Small sample 13.7 GA 0.093 0.357 0.26 10 Small sample 10.5 GA 0.338 0.357 0.95 *2 C concentration at the base steel / plating interface estimated by Experiment No. 7 [Evaluation of steel sheet after hot stamping]

[00106] To evaluate the steel sheet after hot stamping, the steel sheet for evaluation was subjected to hot stamping as follows. First, degreasing was performed by a conventional method to suppress carburization during heating by hot stamping. Then, hot stamping was performed according to the following conditions and heat pattern in Figure 5 to provide a sample after hot stamping. Petition 870250083662, dated 09 / 17 / 2025, pp. 46 / 68 / 48 (Hot stamping conditions)

[00107] • Sample size used: 150 mm L x 70 mm W or 150 mm L x 220 mm W or 150 mm L x 80 mm W (small sample) • Mold used: flat sheet mold<Condição de aquecimento>

[00108] · Set temperature of the atmospheric electric furnace: 910°C • Heating time: the plate temperature reached 870°C and was maintained for 45 s (meanwhile, the plate temperature was controlled to stay within a range of 870°C to 900°C). <Condições de resfriamento>

[00109] · Next, natural cooling was carried out and, when the temperature of the sheet reached 550°C or 700°C, both flat surfaces were pressed with a flat sheet mold and cooled.

[00110] · Pressing load: 0.5 MPa • Pressing speed: 20 spm • Compression amount: 5 mm • Bottom dead center holding time: bottom dead center was held until 50°C or less (in this case, 10 s).

[00111] Using the sample after hot stamping, the tensile strength TS, the LME resistance and similar were evaluated as described in detail below. [Shot blasting]

[00112] For the sample after hot stamping, the strength value of the steel sheet was measured according to the method described in ISO-18594: 2007 (E) regarding surface strength. Shot blasting was performed under the following strength measurement conditions, aiming for 2.0 mΩ or less. Each of the shot blasting conditions is shown in Table 6. In Experiments No. 8 to 10, the strength value after shot blasting was not measured. Petition 870250083662, dated 09 / 17 / 2025, page 47 / 68 / 48 but the average (Experiment No. 1 to 5) of the resistance values ​​of the materials prepared under substantially equal conditions was 0.9 mΩ and, therefore, it is presumed to be substantially the same, and 0.9 (mΩ) is shown in Table 6 below. (Shot blasting conditions)

[00113] · Shot blasting material: GH-3 (0.3 mm grade) • Shot blasting pressure: approximately 0.4 MPa • Shot blasting time per 150 mm x 120 mm area (details of shot blasting time are described in Table 6) is controlled.

[00114] · Shot blasting on both surfaces • Shot blasting was performed until the resistance value of the steel plate became 2.0 mΩ or less. (Conditions for measuring resistance)

[00115] · Three sheets of material measuring 30 mm x 30 mm were cut and collected.

[00116] · Electrode material: Cu-Cr • Electrode diameter: Φ8 mm • Tip R: 40 mm • DC current value: 2 A • Pressure: 350 ± 17.5 x 10 N • The number of measurements for a sample was set to one, and a total of three measurements were performed for each experimental sample.

[00117] • The average value of N3 was adopted as the value.

[00118] • A plated surface of a steel sheet was placed between electrodes and measured.

[00119] • A value obtained by subtracting the configuration resistance from the total resistance was defined as a resistance value. Petition 870250083662, dated 09 / 17 / 2025, page 48 / 68 / 48 [Table 6] Hot Stamping Shot Blasting Experiment No. Heating Temperature (°C) Heating Time (s) Initial Molding Temperature (°C) Shot Blasting Time Resistance Value after Shot Blasting (mΩ) 1 870 45 550 30 s / one side 0.7 2 870 45 550 30 s / one side 0.8 3 870 45 550 30 s / one side 1.0 4 870 45 550 30 s / one side 1.7 5 870 45 550 30 s / one side 0.5 6 870 45 700 120 s / one side 1.7 7 870 45 550 120 s / one side 0.8 8 870 45 700 30 s / one side 0.9 *3 9 870 45 700 30 s / one side 0.9 *3 10 870 45 700 30 s / one side 0.9 *3 *3 Although no measurements were taken, the average resistance value (Experiments No. 1 to 5) of the materials fitted under nearly the same conditions is 0.9 mΩ, and therefore the value is taken as approximately 0.9 mΩ. [Measurement of the decarburized state of the surface layer after hot stamping (carbon profile measurement by GD-OES)]

[00120] As described below, the carbon profile was measured by GD-OES (glow discharge optical emission spectrometry) and the decarburization behavior after hot stamping was examined. (Sample preparation)

[00121] A sample measuring 30 mm x 90 mm x sheet thickness or 30 mm x 70 mm x sheet thickness was collected. It was then degreased according to a conventional method to prepare a sample. Using the sample, the mass % concentration of each element was then measured by GD-OES under the following conditions. (Measurement conditions)

[00122] Device used: Markus High Frequency Glow Discharge Optical Emission Surface Analyzer (rf-GD-OES) GD-Profiler2 manufactured by HORIBA, Ltd.

[00123] Sputtering method: normal sputtering Measuring range: φ4 mm Petition 870250083662, dated 09 / 17 / 2025, page 49 / 68 / 48 Gas type: Air Element to be analyzed: B, C, O, Al, Si, Ti, Cr, Mn, Fe, Zn (in this example, these elements were evaluated, but when elements other than those listed above are contained, for example, in a plated layer or a steel sheet, elements other than those listed above should also be analyzed) (Measurement method)

[00124] The surface of the sample on which the plating was formed was subjected to GD-OES measurement until the depth reached 100 μm in the thickness direction of the plate. (Analysis method)

[00125] The analysis was performed in the same manner as in the measurement of the decarburized state of the surface layer (before hot stamping) described above (measurement of the carbon profile by GD-OES).

[00126] Using the sample after hot stamping, the carbon profile was measured by GD-OES under the conditions described above, and the decarburization behavior was examined. As a comparative example, the carbon profile of Experiment No. 4, which is a conventional steel, is shown on the left in Figure 6, and the carbon profile of Experiment No. 1, which is an example of the present invention, is shown on the right in Figure 6. From the comparison of these carbon profiles, it is verified that, in the example of the present invention, the carbon concentration at the interface between the plating layer and the base steel sheet is sufficiently suppressed after hot stamping, since the difference in carbon concentration at the interface between the plating layer and the base steel sheet is indicated by a double-headed arrow in the vertical direction in Figure 6. In Table 8, “-” in the C concentration at the base steel / plating interface indicates that the measurement was not performed. [Measurement of Fe concentration in the plated layer (after stamping)] Petition 870250083662, dated 09 / 17 / 2025, page 50 / 68 / 48 [hot]

[00127] The Fe concentration in the plated layer after hot stamping was measured in the same way as in the measurement of the Fe concentration in the plated layer before hot stamping. Figure 7 shows an example of an EDX analysis area in the measurement of Fe concentration in the plated layer after hot stamping. As an example of the EDX analysis, the result of the analysis of Experiment No. 4 is shown in Figure 8. In addition, as an example, the results of the calculation of the Fe concentration (53.4% ​​by mass) of Experiment No. 4 are shown in Table 7. The Fe concentration in the plated layer of each example obtained by calculation in the same way as in Table 7 is shown in Table 8 below. [Table 7]___________________________________________________________ Element % by mass % by mass excluding C 7.06 0.0 O 1.7 1.8 Al 0.16 0.2 Si 0.66 0.7 Fe 49.66 53.4 Zn 40.76 43.9 Total 100 100.0 % by mass excluding C 92.94 [Traction test]

[00128] Using the sample after hot stamping, a tensile test was performed under the following conditions, and the tensile strength (TS, unit: MPa) was measured. (Preparation of the test specimen)

[00129] For a material of 150 mm L x 70 mm W x sheet thickness or 150 mm L x 220 mm W x sheet thickness or 150 mm L x 80 mm W (small sample), a sample for collecting a 150 mm L x 30 mm W test specimen was collected from the center of the sheet. Then, a JIS No. 5 test specimen was prepared from a 150 mm L x 30 mm W sample for collecting a test specimen. (Tensile test method) Petition 870250083662, dated 09 / 17 / 2025, page 51 / 68 / 48

[00130] Using the JIS No. 5 specimen above, tensile strength (TS, unit: MPa) was measured by a method specified in JIS Z 2241 at a strain rate of 10 mm / minute using the AG-IS 250 kN autograph tensile tester manufactured by Shimadzu Corporation. [Welding test]

[00131] The sample after hot stamping was cut to prepare a plurality of samples for a welding test with a size of 30 mm x 30 mm x sheet thickness, and a welding test was performed under the following conditions and as shown in Figure 9. In Figure 9, the X in “X kA” on the 2nd pulse (second energization) indicates 15 current conditions in which each 0.5 kA is changed between 5.0 kA and 12.0 kA to be described below. <Condições de soldagem>

[00132] · Pre-marked point: Twenty 6.5 kA welding points were made on a pair of two mild steels, ensuring the point was properly fitted before the main weld. Other conditions for the pre-marked point and the conditions for the main weld are as follows.

[00133] Energization time: 10 cycles Pressure: 1.7 kN Retention time: 1 cycle

[00134] · Main welding: Device name: pressurized servo spot welding device Manufacturer: Nastoa Welding Technologies Co., Ltd Electrode: Cu-Cr with upper and lower dome-shaped radius. Electrode diameter: outer diameter Φ16 mm, tip diameter: Φ6 mm Petition 870250083662, dated 09 / 17 / 2025, pages 52 / 68 / 48 Marking angle: 0° Cooling water flow rate: approximately 2 liters / minute for the top and bottom sections. Pressurization force: 500 kgf Initial pressing time: 60 cycles / 60 Hz Rise: 1 cycle / 60 Hz Initial power-up: Power-up time: 36 cycles / 60 Hz Current value: 4.5 kA Second energization: 18 cycles / 60 Hz Current value: 5.0 kA, 5.5 kA, 6.0 kA, 6.5 kA, 7.0 kA, 7.5 kA, 8.0 kA, 8.5 kA, 9.0 kA, 9.5 kA, 10.0 kA, 10.5 kA, 11.0 kA, 11.5 kA, 12.0 kA Retention time: 10 cycles / 60 Hz<Conjunto da chapa>

[00135] · Double plate assembly, top plate and bottom plate, are steel plates of the same type.

[00136] · A test specimen was prepared to perform the second energization by n1 for a total of 15 current conditions. [Evaluation of LME cracking]

[00137] From the sample (welding test specimen) after the welding test, a test specimen for LME crack evaluation was prepared as follows. Figure 10 is a schematic top view of sample 1 after the welding test in which the top and bottom plates are welded. As test specimen 2 for LME crack evaluation, hatched parts (including a part of weld point 3) in Figure 10 were taken from sample 1 after the welding test. In order to photograph the central part of weld point 3 (the surface of the weld point diameter), the weld point was first cut on the cutting surface 4 considering a polishing margin and then polished. Petition 870250083662, dated 09 / 17 / 2025, page 53 / 68 / 48 so that the central part of the weld point (the surface of the weld point diameter) becomes the observation surface 5.

[00138] Next, observation surface 5 was subjected to an anti-corrosion treatment by a conventional method, such that the HAZ portion and the diameter of the weld point were known. Then, in all samples, the cross-section was photographed (in the direction of the white arrow in Figure 10) with a magnification that reached the HAZ portion. An example of the photograph is shown in Figure 11. This photograph was taken with a magnification of 25 times. There are 15 current conditions for an experiment and therefore 15 samples for LME crack evaluation were photographed for one experiment.

[00139] Crack observation was performed in a total of 8 positions (1) to (8) shown in Figure 11 for a current condition. That is, a total of 120 cracks in positions were confirmed in 15 current conditions x 8 positions. Then, the total number of positions where cracks with a length equal to or greater than 300 μm were confirmed was obtained, totaling 120 positions. In (1) to (6) of Figure 11, cracks (surface cracks) were easily observed in which the cracks extend substantially in the direction of the plate thickness from the surface, and in (7) and (8) of Figure 11, cracks (internal cracks) were easily observed that extend substantially in the direction of the center of the weld point. The void space Q shown in Figure 12 is not a crack. An internal crack R that extends from the void space Q shown in Figure 12 is counted.

[00140] These results are shown in Table 8. In the properties shown in Table 8, the case where the tensile strength TS after hot stamping was 1,470 MPa or more and the result of the crack evaluation (total number of positions where LME cracking was confirmed) after the welding test was 3 or less was considered an example of an invention with high strength and excellent LME resistance. The tensile strength TS Petition 870250083662, dated 09 / 17 / 2025, pp. 54 / 68 / 48, may be 1,500 MPa or more, 1,550 MPa or more, and 1,600 MPa or more. In contrast, a comparative example was considered in which at least one of the results of the strength and crack evaluation after the welding test did not meet the evaluation criteria above. In the present embodiment, the case in which the Fe concentration in the plated layer was 65% by mass or less was evaluated as excellent in corrosion resistance. The results of the Fe concentration measurement in the plated layer are also shown in Table 8. [Table 8] Experiment No. Plating state after hot stamping Properties C concentration at the base steel / plating interface [Cf] (% by mass) Volumetric C concentration [Cb] (% by mass) Tensile strength TS (MPa) Crack evaluation result after welding test * Fe concentration in the plating layer (% by mass) Corrosion resistance 1 0.22 0.22 1618 0 44 O 2 0.29 0.22 1618 1 43 O 3 0.24 0.22 1611 1 49 O 4 0.30 0.22 1647 4 53 O 5 0.32 0.22 1642 5 50 O 6 0.10 *7 0.085 Approximately 1300 *4 0 60 *6 O 7 0.10 0.085 1222 0 *5 59 O 8 - 0.355 1925 3 44 or less *8 O 9 - 0.357 1875 3 53 or less *9 O 10 - 0.357 1935 6 53 or less *9 O * The total number of positions where cracks with a length of 300 μm or more were confirmed was 120. *4 Estimated presumed resistance from Experiment #7 *5 Estimated number of cracks from Experiment #6 *6 Fe concentration in the plated layer estimated from Experiment #7 *7 C concentration at the base steel / plating interface estimated from Experiment #7 *8 Although no measurements were taken, the % of Fe after hot stamping is largely determined by the base weight before hot stamping and the % of Fe, provided that the hot stamping conditions are the same. Therefore, Experiment No. 1 (base weight: 120 g / m2 and % of Fe before hot stamping: 8.8%) was reported. The percentage of iron (Fe) before hot stamping in Experiment #8 is the same as in Experiment #1, but due to the large base weight, it is considered lower than the percentage of iron (Fe) after hot stamping measured in Experiment #1. Therefore, it was defined as 44% or less. *9 Although no measurements were taken, Experiment No. 4 (base weight: 113 g / m2 and % Fe before hot stamping: 12.0%) was reported. In experiments #9 and #10, the % of Fe was equivalent to that of experiment #4, but, due to the large base weight, the % of Fe after hot stamping was considered less than 53% of experiment #4. Therefore, 53% or less was defined.

[00141] Based on the results above, the following was found. Experiments #1 to #3, 8 and 9 satisfy the composition of components and the Petition 870250083662, dated 09 / 17 / 2025, page 55 / 68 / 48 production conditions (reduction annealing conditions) specified in this embodiment and, as a result, the tensile strength (TS) after hot stamping satisfies 1,470 MPa or more. Furthermore, the carbon concentration of the surface layer of the steel sheet before hot stamping satisfied formula (1), and excellent LME resistance was exhibited with three or fewer LME cracking positions after welding. In this example, LME resistance was evaluated by welding after hot stamping, but LME resistance is also a necessary property at the time of high-temperature hot stamping. That is, LME resistance is also required for a hot-dip galvanized steel sheet before hot stamping.In experiments 1 through 3, 8, and 9, hot stamping was performed favorably, and therefore it can be said that hot-dip galvanized steel sheets for hot stamping in these examples are also excellent in LME resistance.

[00142] In contrast, Experiments No. 4 to 7 and 10 did not satisfy at least one of the component compositions and production conditions (reduction annealing conditions) specified in this embodiment, and the desired properties were not obtained.

[00143] Experiments No. 4 and 5 satisfied the component composition specified in this embodiment, and the tensile strength after hot stamping was 1,470 MPa or more. However, in these examples, the production conditions (reduction annealing conditions) were not met, and the dew point at the time of reduction annealing was -20°C or less. As a result, the carbon concentration of the surface layer of the steel sheet before hot stamping did not meet formula (1) and, therefore, the total number of cracks found in the LME strength assessment was 4 or more, resulting in low LME strength. Petition 870250083662, dated 09 / 17 / 2025, pages 56 / 68 / 48

[00144] In experiments No. 6 and 7, the amount of C in the component composition was less than the range specified in this embodiment and, therefore, the tensile strength (TS) after hot stamping was less than 1,470 MPa. Experiments No. 6 and 7 did not meet the production conditions (reduction annealing conditions) and the carbon concentration of the surface layer of the steel sheet before hot stamping did not meet formula (1), but the total number of LME cracking positions was 3 or less in the LME strength assessment. The reason is that the volume components, in particular carbon, were quite low.

[00145] Experiment No. 10 satisfied the component composition specified in this embodiment, and the tensile strength after hot stamping was 1,470 MPa or more. However, the production conditions (reduction annealing conditions) were not met, and the dew point at the time of reduction annealing was -20°C or less. As a result, the carbon concentration of the surface layer of the steel sheet before hot stamping did not meet formula (1) and, therefore, the total number of cracks found in the LME strength assessment was 4 or more, resulting in low LME strength.

[00146] Table 8 includes some estimated values ​​from Experiments 6 to 10, and therefore this point will be described below. First, the C concentration at the base steel / plating interface after hot stamping in Experiment 6 was not measured. However, in Experiment 6, the component composition is the same as in Experiment 7, and the reduction annealing conditions are similar. Furthermore, the heating conditions for hot stamping are almost the same, and therefore it is assumed that the C concentration at the base steel / plating interface is equivalent to that of Experiment 7. Therefore, the value is described assuming that the C concentration at the base steel / plating interface after hot stamping in Experiment 6 is Petition 870250083662, dated 09 / 17 / 2025, pp. 57 / 68 / 48, is substantially the same as in Experiment No. 7.

[00147] Furthermore, in Experiment No. 6, the tensile strength after hot stamping is not measured. However, Experiment No. 6 has the same component composition as Experiment No. 7, and the reduction annealing conditions are also similar. In addition, the heating condition by hot stamping and the shot blasting condition are almost the same. In contrast, the initial molding temperature at the time of hot stamping in Experiment No. 6 is higher than in Experiment No. 7, and therefore it is assumed that the cooling rate after hot stamping is higher than in Experiment No. 7. Therefore, it is assumed that the formed martensite microstructure is also hardened. Furthermore, assuming that the strength is increased by about 80 MPa, the estimated strength (approximately 1,300 MPa) based on the value from Experiment No. 7 is described.

[00148] Furthermore, in Experiment No. 6, the Fe concentration in the plated layer after hot stamping is not measured. However, Experiment No. 6 has the same component composition as Experiment No. 7, and the reduction annealing conditions are also similar. In addition, the hot stamping heating condition and the shot blasting condition are the same. In contrast, the coating weight of Experiment No. 6 is less than that of Experiment No. 7, assuming that the Fe concentration in the plated layer is approximately 1% greater than that of Experiment No. 7. Therefore, the Fe concentration in the plated layer after hot stamping in Experiment No. 6 is assumed to be approximately 60% based on the value of Experiment No. 7, and the assumed value is described.

[00149] In Experiment No. 7, the LME cracking assessment was not performed. However, Experiment No. 7 has the same component composition as Experiment No. 6, and the reduction annealing conditions. Petition 870250083662, dated 09 / 17 / 2025, pp. 58 / 68 / 48, are also similar. Furthermore, the heating condition by hot stamping and the shot blasting condition are the same. Additionally, it is assumed that there is no significant difference in the Fe concentration assumed in the plated layer after hot stamping. Therefore, the LME crack of Experiment No. 7 is assumed to be 0, as in Experiment No. 6, and thus the assumed value is described.

[00150] In Experiment No. 8, the Fe concentration in the plated layer after hot stamping is not measured. However, the Fe concentration in the plated layer after hot stamping is largely determined by the weight of the coating (base weight) before hot stamping and by the Fe concentration in the plated layer, provided that the hot stamping conditions are the same. In this document, Experiment No. 1 was mentioned (coating weight (base weight): 120 g / m2, Fe concentration in the plated layer: 8.8% by mass). The Fe concentration in the plated layer before hot stamping in Experiment No. 8 was equivalent to that of Experiment No. 1, while the weight of the coating (base weight) in Experiment No. 8 was greater than in Experiment No. 1. Therefore, it is assumed that the Fe concentration in the plated layer after hot stamping in Experiment No. 8 is less than the value (44% by mass) measured in Experiment No. 1.Thus, as an assumed Fe concentration in the plated layer after hot stamping in Experiment No. 8, 44% by mass or less was described in Table 8.

[00151] In experiments #9 and #10, the Fe concentration in the plated layer after hot stamping is not measured. However, as described above, the Fe concentration in the plated layer after hot stamping is largely determined by the weight of the coating (base weight) before hot stamping and by the Fe concentration in the plated layer, provided that the hot stamping conditions are the same. In this document, Experiment #4 was mentioned. A Petition 870250083662, dated 09 / 17 / 2025, p. 59 / 68 / 48 The concentration of Fe in the plated layer before hot stamping in Experiments No. 9 and 10 was equivalent to that of Experiment No. 4, while the weight of the coating (base weight) in Experiments No. 9 and 10 was greater than in Experiment No. 4. Therefore, it is assumed that the concentration of Fe in the plated layer after hot stamping in Experiments No. 9 and 10 is less than the value (53% by mass) measured in Experiment No. 4. Thus, as an assumed concentration of Fe in the plated layer after hot stamping in Experiments No. 9 and 10, 53% by mass or less was described in Table 8.

[00152] In all Experiments No. 1 to 3, 8 and 9, the coating weight was 45 g / m2 or more and the Fe concentration in the plated layer after hot stamping was 65% by mass or less, and therefore, excellent corrosion resistance is considered to have been shown.

[00153] This application claims priority based on documents JP-2023-056200, filed on March 30, 2023, and JP-2024-022727, filed on February 19, 2024. Documents JP-2023-056200 and JP2024-022727 are incorporated herein by reference. LIST OF REFERENCE SIGNS Sample after welding test (welding test specimen) Test specimen for LME cracking assessment Welding point Cutting surface Observation surface a Central part of steel plate b End part of steel plate Q Empty space R Internal cracking

Claims

1. Galvanized steel sheet for hot stamping, characterized in that the composition of components of a base steel sheet satisfies: C: 0.15 to 0.50% by mass; Si: 0.02 to 2.5% by mass; Mn: 0.5 to 5% by mass; P: 0.03% by mass or less (including 0% by mass); S: 0.02% by mass or less (including 0% by mass); Al: 0.010 to 1% by mass; Ti: 0.005 to 0.080% by mass; and B: 0.0005 to 0.005% by mass, with the remainder being Fe and unavoidable impurities, when elemental analysis is performed in the thickness direction of a plated layer from a plated layer surface by glow discharge optical emission spectrometry (GD-OES), a carbon concentration [Cf] (% by mass) at a position where a Zn concentration constituting the plated layer is 1.0% by mass and a volumetric carbon concentration [Cb] (% by mass) satisfy the following formula (1): [Cf] < 0.65 x [Cb] (1) 2. Hot-stamped galvanized steel sheet according to claim 1, characterized in that a composition of components of the base steel sheet satisfies one or more of the following (a) and (b): (a) additionally includes one or more elements selected from the group consisting of Cr: more than 0% by mass and 1.2% by mass or less; Mo: more than 0% by mass and 1% by mass or less; and Ca: more than 0% by mass and 0.0040% by mass or less, and (b) additionally includes one or more elements selected from the group consisting of Nb: more than 0% by mass and 0.040% by mass or less; V: more than 0% by mass and 0.30% by mass or less; Cu: more than 0% by mass and 0.30% by mass or less; Ni: more than 0% by mass and 0.30% by mass or less; Mg: more than 0% by mass and 0.010% by mass or less; and REM: more than 0% by mass and 0.010% by mass or less.

3. Method for producing a galvanized steel sheet for hot stamping, characterized in that the method comprises: an annealing step comprising holding a hot-rolled steel sheet or a cold-rolled steel sheet that satisfies the component composition as defined in claim 1 or 2 at 500 to 930°C for 90 to 1,000 seconds in a reducing atmosphere with a dew point of -20°C to +10°C; and a subsequent galvanizing step.

4. Method for producing galvanized steel sheet for hot stamping according to claim 3, characterized in that the galvanizing step is a hot-dip galvanizing step.

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