TW201127967A - Hot-pressed steel article and method for production thereof - Google Patents

Abstract

Provided are a hot-pressed member which has excellent hot-press formability, spot weldability, and coating adhesion and in which corrosion-induced penetration of hydrogen into the steel can be inhibited, and a process for producing the member. The hot-pressed member comprises a steel plate constituting the member, an Ni diffusion region formed on the surface layer of the steel plate in an amount of 10-90,000 mg/m2 in terms of deposited Ni amount, and an inorganic compound disposed on the Ni diffusion region.

Description

201127967 VI. Description of the Invention: [Technical Field] The present invention relates to a hot-pressed member manufactured by press-working a heated steel sheet, in particular, relating to a vehicle chassis portion or a vehicle body structure portion. A hot pressing member used and a method of manufacturing the same. [Prior Art] Conventionally, most automobile chassis members, vehicle body structural members, and the like are manufactured by pressurizing and applying a steel plate having a predetermined strength. In recent years, from the viewpoint of protecting the global environment, people are eager to lighten the weight of the car body, and are constantly striving to increase the strength of the steel plate used to reduce the thickness of the plate. However, as the strength of the steel sheet increases, the press workability is lowered, so that it is difficult to process the steel sheet into a desired member shape. Therefore, in Patent Document 1, a processing technique called hot pressing has been proposed in which a heated steel sheet is processed while being quenched using a die including a die and a punch. This makes it easy to process and increase the strength at the same time. However, there are the following problems in the hot pressing: Since the steel sheet is heated to a high temperature of about 95 TC before hot pressing, scale (Fe oxide) is formed on the surface of the steel sheet, and the scale will be When the hot pressure falls off, the mold is damaged or the surface of the member after the hot pressing is damaged. Moreover, the scale remaining on the surface of the member may also cause poor appearance or film adhesion (coating property) or corrosion resistance. Therefore, it is usually treated with pickling or bead blast to remove the scale on the surface of the component, but it will make the process become complicated, which will lead to a decrease in productivity. There is an urgent need for a hot-pressed steel sheet which is capable of suppressing the formation of _ scale during heating before hot pressing, and which is excellent in durability and coating adhesion, and proposes a steel sheet for hot pressing which is provided with a coating such as a mineral layer on the surface and used. A hot pressing method thereof. For example, 'Patent Document 2' discloses a coated steel sheet coated with an Ai or Al alloy. It is also disclosed that by using the coated steel sheet, decarburization is prevented during heating before hot pressing. Or oxidize' to get extremely high Further, in Patent Document 3, a hot pressing method is disclosed in which a steel sheet coated with a Zn or Zn matrix alloy is hot pressed, and heated before hot pressing. An alloy compound such as a compound of a Zn-Fe matrix having a lubricating function or a compound of a zn-Fe-Al matrix is formed on the surface of the steel sheet to prevent money or decarburization, and a member manufactured by the method, particularly In the hot-pressed member using the steel sheet coated with Zn_5〇 to 55% by mass of A1, a Zn-Al-Fe alloy layer is formed, whereby an excellent anti-corrosion effect can be obtained. Further, in Patent Document 4, the following is disclosed. Hot pressing method excellent in hydrogen embrittlement resistance: a steel plate coated with A1 or Zn as a main body is used, and heated to a level above the Ac3 metamorphic point in an environment with a hydrogen concentration of 6 vol. / 〇 or less and a dew point of 10 ° C or less. Hot pressing at a heating temperature below °C. In the hot pressing method, the amount of hydrogen or water vapor in the ring is reduced during heating to reduce the amount of hydrogen infiltrated into the steel, thereby avoiding more than 1000 High strength of MPa Hydrogen embrittlement 0 [Patent Document 1] British Patent No. 1490535 [Patent Document 2] Japanese Patent No. 3931251 [Patent Document 3] Japanese Patent No. 3663145 [ [Problems to be Solved by the Invention] However, the techniques described in the above Patent Documents 2 to 4 have the following problems: When the pressure is pressed, the mold is easily occluded (not referring to the rust from the surface of the steel plate. • The mold causes damage, * refers to the phenomenon that the steel plate is bonded due to the contact of the metal faces), and the loss is poor. When the button is coated with a ^A1 alloy, the welding current range is narrow and the spot weldability is poor. If the (4) Cai 2 „ or 211 alloy 顺 = hot heat & will be volatile, and removed to the steel sheet surface ^ the coating adhesion is reduced. Compared with the use of,,, and pressure components in the use environment Corrosion produces a leaching infiltration, which is accompanied by the infiltration of i β to cause hydrogen tires &

SUMMARY OF THE INVENTION An object of the present invention is to provide adhesion of 1 H paint, and to suppress the pressure, the clickability, the article, and the method for producing the same. f. The hot press structure infiltrated into the steel with the smear. (The means for solving the problem) The present inventors have found the following findings as a result of the study. L❸'s hot-pressed components are studied intensively. 099136873 201127967 i) Lai·Into the steel plate using Ni or]sji* A σ1 plated steel plate is used as a material for excellent spot welding or coating.焱) ii) If an inorganic compound is present on the Ni or Ni alloy #...X,' plate, it is excellent in hot pressability. ~ · Μ 传 若 若 若 若 若 若 若 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 用以 。 。 。 。 。 。 。 。 ', Hong Ben 1 is based on the above findings, and provides a hot-pressed member, which is characterized in that 'the surface of the steel sheet for constituting the member has a Ni adhesion amount of ...~^(^ The inorganic compound is present on the surface of the hot-pressed member of the present invention. The inorganic compound having a melting point of 500 to 1000 tons and containing an alkali-soluble component is preferred. It is produced by the following method: after the steel sheet surface has a Ni adhesion amount of 1 〇 to 90000 mg/m 2 and the Ni-containing recording layer and the inorganic compound steel sheet are heated to an Acs transformation point of 1200 ° C. The inorganic compound is preferably an inorganic compound having a melting point of 5 Å to 100 Å and containing an alkali-soluble component. Further, as the steel sheet, it is preferred to use a steel sheet having the following composition, that is, °/❶ means 'containing C: 0.15 to 0.5%, Si: 〇·05~2.〇%, Μη: 0.5 to 3%, P: 0.1% or less, s: 0.05% or less, Α1: 0.1% or less, Ν : 0.01% or less, and the rest Containing Fe and impurities which are not avoided; or expressed in mass%, further individual 099136873 6 201127967 or at least one selected from the group consisting of ~0.08% (invention effect)

Cr: 〇, 〇i~i%, Ti: 〇. 2% J^, B 1 type, Sb: Please 3~ 〇 。. Steel plate. : 0.0005 According to the present invention, the contact property, and the excellent thermal hysteresis, spot weldability, and coating of the τ 4 ^ are accompanied by imperfections in the hot-pressed members of the invention. A disk member or a vehicle body structural member. [Embodiment] 1) Hot-pressing member The Ni-diffusion region is present in the hot-pressing member of the present invention, and the reason for suppressing hydrogen accompanying the surface layer portion of the steel sheet is not necessarily clear, but it can be considered as follows. That is, thus ==. Although the internal structure of the steel plate and the wet environment TF ¥ to the emulsion of the gas is cold and the enthalpy is affected by the original reaction, it is a stable rust that is not easy to change. In order to make the β-finanization, it is effective to add the presence of the milk diffusion zone to inhibit the enthalpy. In addition, the term "Ni diffusion region" as used herein refers to a region in which Ni diffuses from the money layer into the steel during heating before hot pressing, or, in addition to NU乂, is contained in the bell layer, u〇, Zn, Cr, Mn. The area where metal elements such as Cu and M〇 diffuse. However, in order to effectively suppress the above-described suppression of hydrogen permeation, it is necessary to set the Ni adhesion amount of the mother-side single surface in the Ni diffusion region to 1 〇 mg/m 2 or more, preferably 5 〇 mg/m 2 or more, more preferably 100 mg. /m2 or more. On the other hand, if the Ni adhesion amount per surface of the single 099136873 7 201127967 exceeds 90,000 mg/m2, the effect is saturated and the cost increases. Therefore, the Ni adhesion amount must be 90,000 mg/m2 or less, preferably 10,000 mg/m2 or less. More preferably, it is 5 〇〇〇 mg/m2 or less. Further, it is preferable that the diffusion region is present in a range from 1 to 50 #m from the surface of the steel sheet for forming the member throughout the depth direction, and more preferably in the range of 1 to 50 #m from the surface. It exists in the range of 3 to 10/zm from the surface. The amount of Νι adhesion can be determined by fluorescent ray analysis or wet analysis. The depth of the diffusion zone can be obtained by analyzing the thickness direction profile using EPMA (Electr〇I1 Pr〇be Micro Analyzer 'electron probe microanalyzer) or analyzing the depth direction by GDS (Glow Discharge Spectroscopy). . The hot-pressed member of the present invention is produced by hot-pressing a steel sheet having a plating layer containing Ni and an inorganic compound in this order. Therefore, the inorganic compound remains on the surface of the member after hot pressing. However, the inorganic compound is subsequently subjected to a chemical conversion treatment such as a phosphate treatment or a cerium oxide treatment to the hot-pressed member to be removed as a coating substrate, particularly in the case of degreasing, so that the coating adhesion or the like is not impaired. 2) Manufacturing method The hot-pressing member of the present invention can be produced by heating a steel sheet containing a plating layer of Ni and an inorganic compound on the surface of the steel sheet in such a manner that the Ni adhesion amount per one side is 10 to 90,000 mg/m 2 . To A. The abnormal point is ~12〇〇t>c 099136873 8 201127967 After the temperature range is hot pressed. The steel sheet containing the Ni plating layer having a Ni adhesion amount of 1 〇 to 90,000 mg/m2 as described above was heated to an Ac3 transformation point of 1200. (In the temperature range, Ni of the plating layer is diffused into the steel sheet, and a Ni diffusion region having a Ni adhesion amount of 10 to 90,000 mg/m 2 is formed in the surface layer portion of the member, thereby suppressing penetration of hydrogen into the steel accompanying corrosion. It is not a zn containing A1 or a low boiling point, but a plate containing a coating of Ni having a high melting point and a high boiling point, that is, a coating of Ni or a Ni alloy, so that no rust is generated, and excellent spot weldability or Coating adhesion The above-mentioned Ni-containing plating layer can be formed by an electroplating method or the like. If an inorganic compound is present on the plating layer containing Ni and the inorganic compound is melted upon heating before hot pressing, the fluid lubricating effect is obtained. The slidability at the time of hot pressing can be remarkably improved. 'The mold will bite due to the material, and (4) excellent hot pressing property is obtained. Since A, as the inorganic compound, it is preferable to use the glaze to obtain an inorganic compound of ～100 (TC). If the melting point of the inorganic compound is set to 5 Å or more, the inorganic compound does not melt in the fast stage of the heating process during the heating before the hot pressing, so the inorganic compound which has been glazed does not adhere to the heating. The amount of the inorganic compound in the smelting state is not reduced, and the slidability at the time of hot pressing can be improved. On the other hand, if the sleek point of the inorganic compound is set to 100 (the following rc), the inorganic compound does not marry upon heating. Or there may be no case where the smelting is insufficient. The slidability will increase when hot pressing. Furthermore, it is more preferable to use an inorganic compound with a scent of 500 to 900 ° C. 099136873 9 201127967 as an inorganic compound It is preferable to use an inorganic compound containing an alkali-soluble component so as to be easily removed when the alkali of the chemical conversion treatment is degreased. If the amount of the mother-only one-side adhesion of the inorganic compound is set to 1 mg/m2 or more, the state of the state is smeared. The amount of the inorganic compound is not too small, and the slidability at the time of hot pressing is sufficient. When the amount is 5,000 mg/m 2 or less, the effect of improving the slidability can be obtained economically, and a large amount of inorganic compound does not remain after hot pressing. Therefore, the unevenness of the chemical conversion treatment or the coating treatment is not caused, and the adhesiveness of the coating can be made Φί:South', so it is preferably set to 1 to 5 〇〇〇mg/m2. Here, the adhesion amount of the inorganic compound is obtained. , For example, it can be measured by the method shown below, that is, a method of measuring the change in weight before and after coating and drying the inorganic compound; and the inorganic compound is dissolved and removed by a solution in which only the inorganic compound can be dissolved, and the change is performed by weight change. a method for measuring; and analyzing the solution together with an ore layer to which an inorganic compound is attached and/or glutamic acid in an acid 'Atomic Absorption analysis or ICP (Inductively Coupled Plasma) analysis, etc. The amount of the element to be labeled is quantified and converted into the amount of the inorganic compound. The inorganic compound may be immobilized on the plating layer containing Ni, and the organic material may be present in the inorganic compound. However, since the effect of asking the slidability at the time of heat is an inorganic compound, when the inorganic compound and the organic compound are coexisted, it is preferable to set the ratio of the inorganic compound to 50---L 0/I. / L -j- M Furthermore, even if the organic compound coexists, the heating before the hot pressing is carried out at a high temperature of about 900 C. Therefore, the organic compound reacts with 099136873 201127967 in the atmosphere to become carbon dioxide or water. It disappears, so it does not have any effect on the slidability or the bond layer. As such an inorganic compound, for example, the melting point is 741. (:, sodium sulphate decahydrate (borax) having a boiling point of 1575 C. However, according to the heating conditions before hot pressing, the sodium tetraborate decahydrate becomes an anhydride at 350 to 400 ° C. The temperature is further increased at 878 ° C. Therefore, the tetradecanoic acid decahydrate is suitable for the case where the heating temperature before hot pressing is 878 ° C or more. Further, as an inorganic compound which can be applied to the present invention, Examples thereof include sulfuric acid, cerium nitrate, cerium oxide (111), calcium hydroxide, sodium carbonate, sodium fluoride, etc. In order to allow an inorganic compound to be present on the plating layer containing Ni, a known method can be applied. For example, the following may be mentioned. Method: a solution such as an aqueous solution containing an inorganic compound is applied onto the surface of the money layer, and dried to thereby evaporate water or a solvent, thereby allowing an inorganic compound to be present on the plating layer. As a coating method, a bar coating method may be mentioned. Brushing method, roll coating method, dipping method, and spraying method. In the method for manufacturing a hot-pressing member according to the present invention, it is necessary to perform heating before hot pressing to bring the temperature of the steel sheet to the point of change of Ac3 to 12 〇〇π, as Heating method The heating by a electric furnace, a gas furnace, or the like, flame heating, electric heating, high-frequency heating, induction heating, etc. can be applied. The steel sheet for a hot-pressing member of the present invention is preferably used after hot pressing. A steel sheet having a strength of 980 MPa or more and excellent in hardenability is obtained. For example, it is preferable to use a steel sheet having the following composition grade: expressed by mass % 'containing C: 0.15 099136873 201127967 to 0.5%, Si: 0.05 to 2.0%, Μη: 0.5~30/0, p: 〇1〇/〇 below 0.05. 0.05% or less, Α1: 0.1% or less, Ν: 0.01% or less, and the rest contains Fe and unavoidable impurities; or expressed in mass%, further Individually or simultaneously containing at least Cr: 0_01~1〇/〇, Ti: 〇.2% or less, B: 〇〇〇〇5 ～0.08% at least! Species, Sb: 0.003~〇〇3〇/〇 The reason for the limitation of each component element is as follows. Unless otherwise specified, the "%" of the content of the component means "% by mass. C: 0.15 to 0.5% C is used to increase the strength of the steel. Element, in order to make the hot pressing member Ts (Te (four) e Strength, tensile strength When the amount is 980 MPa or more, the amount must be 〇1 or more. On the other hand, if the amount of C exceeds 〇.5%, the blanking workability of the steel sheet of the material is remarkably lowered. It is 〇15~〇5%. Si : 0.05~2·0ο/0

Si is the same as C, and the element for increasing the strength of steel is such that the TS of the hot-pressed member is 980 MPa or more, and the amount thereof must be made 05% or more. On the other hand, if the amount of Si exceeds 2.0%, the occurrence of surface defects called red rust at the time of hot rolling is remarkably increased', and the rolling load increases, resulting in deterioration of ductility of the hot-rolled steel sheet. In addition, when the amount of Si is more than 2.0%, there is a case where the plating treatment is performed on the surface of the steel sheet to form a plating sheet mainly composed of Zn or A1. Therefore, the amount is set to 0.05 to 2.0%. Μη : 0.5~3〇/〇099136873 12 201127967 The Μη system suppresses the ferrite metamorphism and improves the hardenability as an element of Dundee, and also reduces the metamorphic point, so it is also used to reduce the heating temperature before the hot pressing. An effective element. In order to exhibit such an effect, the amount must be set to 〇.5% or more. On the other hand, when the amount of Μη exceeds 3%, segregation occurs, and the uniformity of the characteristics of the steel sheet and the hot-pressed member of the material is lowered. Therefore, the amount of Μη is set to 0.5 to 3%. Ρ : 0.1% or less

When the amount of niobium exceeds 0.1%, segregation occurs, and the uniformity of the characteristics of the steel sheet and the hot-pressed member of the material is lowered, and the toughness is also lowered. Therefore, the P amount is set to be 0_1% or less. π «μ- S : 0.05% or less If the amount of S exceeds 0.05%, the amount is set to 0. 05% or less. Α1 : 0.1% or less The _ of the hot-pressed member will decrease. therefore

S Therefore, the workability or quenching is not covered. If the amount of Α1 exceeds 0.1%, the steel property of the material is lowered. Therefore, the amount of Α1 is set to 0.1. /〇以Ν : 0.01% or less The formability or hardenability is lowered when heated before the start. When the amount of niobium exceeds 0.01%, the nitride of the material is not covered by the nitride at the time of hot rolling, and therefore, the amount of niobium is 0.01% or less. Although the remainder is Fe and the unavoidable 铋& 筲, it is preferably individually or simultaneously selected from the group consisting of Cr: nn · 01 〜1%, Ti: 0·2〇/〇099136S73 13 201127967 Species, Sb: 0.003~0.03%. Below, B: 0.0005~〇·〇8〇/0 at least Cr: 0.01 to 1%

The Cr system is an element effective for strengthening steel and increasing quenching. In order to exhibit such an effect, it is preferable to set the amount of Cr to 〇 〇 1% or more. On the other hand, if the amount of Cr exceeds 1%', the cost is high, so it is preferable to set the upper limit to 1%.

Ti : 0.2% or less Τι is an effective element for strengthening steel and making it more effective by fine granulation. Further, the nitride is more preferentially formed than the following, and the effect of improving the hardenability by the solid solution β is exhibited as an effective element. However, if the amount of bismuth exceeds 0.2%, the rolling load at the time of rolling will be extremely increased, and the workability of the hot-pressing member will be lowered. Therefore, it is difficult to set the upper limit to Q 2% or less. B : 0.0005 to 0.08% B is an effective element for improving the hardenability or the reduction of the viscosity during hot pressing. In order to exhibit such an effect, it is preferable to set the amount of B to 〇 5% or more. On the other hand, if the amount of B exceeds 〇.〇8%, the rolling load during hot rolling is extremely increased, and after the hot rolling, a martensite phase or a bainite phase is generated. Since the fracture of the steel sheet or the like occurs, it is preferable to set the upper limit to 0.08%.

Sb: 0.003~0.03%

Sb has the effect of suppressing the decarburization layer of 099136873 14 201127967 generated in the surface layer portion of the steel sheet by heating the steel sheet before hot pressing to cooling the steel sheet by one series of hot pressing. In order to exhibit such an effect, the amount must be set to 0.003% or more. On the other hand, when the amount of Sb exceeds 0.03%, the rolling load is increased and the productivity is lowered. Therefore, the amount of Sb is set to be 0.003 to 0.03%. The heating method before the hot pressing may, for example, be heating by an electric furnace or a gas furnace, flame heating, electric heating, high-frequency heating, induction heating, or the like, but is not limited thereto. [Examples] Cold rolling was carried out at a current density of 10 A/dm2 in a 300 g/L nickel sulfate hexahydrate, a 5 〇g/L sodium sulphate, and a 30 g/L sulphuric acid ore bath. The steel plate is subjected to a key treatment to form a N1 money layer having a different adhesion amount (each one side) as shown in Table 1. The above-mentioned cold-rolled steel sheet has a steel sheet having the following composition. It is expressed as λ%, and contains c: 〇23%, Si: 〇12%, Mn: (5%, Ρ · 'S: 0·01%, A1 ··0.03%, N: 0.005%, Cr: 0.4%, and B · 0.0022%, and the rest Contains Fe and unavoidable impurities, and the AC3 metamorphic point is 818, the plate thickness is h6mm. In addition, for a part of cold-rolled steel sheet 'containing 3〇〇g/L of nickel sulfate hexahydrate, 1〇g/L Zinc sulfate sulphate 4 Do not use 50 g/L sodium sulphate, 3 〇g/L acid-cut mirror bath, perform electric ore treatment with electric muscle density 50 A/dm2, form the table shown on both sides The amount of the valence is just 0% by mass of the Zn ore layer. Secondly, by the bar coater on the formed Ni county or Nmq f paper (four), the coating is as shown in Table 1; Compound water, followed by 10 The dryness of the bell is from the inorganic compound of the surface of each of the sheets 1 to 0136136873 15 201127967. The 200 mm of the steel sheet having the coating layer containing Ni and the inorganic compound on both sides thus prepared is < The 220 mm blank is heated in the electric furnace of the atmosphere at the heating temperature shown in Table 1 for 1 minute, and then taken out from the furnace. Immediately, the pressure method schematically shown in Fig. , is used. The surface of the plating layer containing Ni and the inorganic compound is brought into contact with the non-punching machine to perform rolling processing, and the hot pressing member Noj — w is produced. At this time, the width of the punching machine is set to 70 mm. The processing height is set to 3 mm. In addition, for comparison, a steel sheet having a Ni plating layer in which no inorganic compound is present, and an AM 〇 mass of 4 〇〇〇〇 mg/m 2 of plating per one side is used. In the same manner, the hot-pressed members N〇i6 to 18 are produced by plating the steel sheets and the cold-rolled steel sheets. Further, since the cold-rolled steel sheets n〇18 used as the comparative material are rust-producing due to the heating at the time of hot pressing, Sprayed by beads after hot pressing After the rust removal of the surface was removed, the evaluation was carried out. Then, the sample was selected from the flat portion of the head of the member, and the depth of the Ni diffusion region of the contact surface of the non-punch machine was measured by the above method. Further, the hot pressing was investigated by the following method. Properties, spot weldability, coating adhesion and hydrogen infiltration resistance. / Hot pressing property: By visually observing the non-punching machine contact surface side after hot pressing, the damage caused by the mold biting is evaluated on the following basis. The state, as long as it is 〇, △, satisfies the object of the present invention. 〇: There is no damage on the surface of the component △: There is damage in one part of the surface of the component. 099136873 201127967 ><: The entire field of the surface of the component is damaged. Spot weldability: from the head of the component - the sample is taken, and the sample is used. )

Ik point machine, using electrode tip (electrode tip): DR6, electrode plus force. 2KN, extrusion (sq . . . Ze) time. 25 cycles / 50 Hz, welding time. 16 cycles / 50 Hz, kept under the condition of ^ μ ^ 曰. period / 5 ,, the same kind of samples were welded to each other, and the k range of the splicing pen (ACR (Adjust current range)) was measured. The evaluation was carried out on the basis of the following, and ◎, 〇, that is, the present invention was satisfied. Further, the non-punching machine contact faces are brought into contact with each other and welded. ◎ . ACR is more than twice as large as that of Al-Si plated steel: ACR is more than 15 times that of A1_Si ore plate ~ less than 2 times X: ACR is equal to or higher than Al_Si ore plate ~ less than Μ times coating adhesion : From the flat part of the head of the component, (4) PB_L3〇2〇 manufactured by Sakamoto P-g Co., Ltd., after the formation of the non-punching machine contact surface in the rod condition, at 17 (rCx2Q minutes) With the condition, the electrophoretic coating (de_depositionpaint) GT_10HT gray manufactured by Kansai Paint Co., Ltd. was formed into a film with a film thickness of 2 〇 (4) to prepare a coating test piece. Then, a mesh tape peeling test was performed, that is, the test was performed. The film is cut by wearing a cutter until it reaches the steel chain of the grid (ι_, 1 mm interval), and is attached by adhesive tape.

Combined and stripped. The evaluation was carried out on the basis of the following. As long as it is 〇, Δ, it satisfies the purpose of the present invention. X 099136873 17 201127967 〇: no peeling △: peeling in 1~10 grids X: peeling hydrogen infiltration in more than 11 grids: sample is selected from the flat part of the head of the component, One side (perforated contact surface) was mirror-polished to make the plate thickness 丨mm. Next, a working electrode is used as a sample, and the counter electrode is made of Ni-plated on the polishing surface to form a hydrogen detecting surface, and is attached to the electrochemical cell schematically shown in FIG. The non-polishing surface is etched in the atmosphere at room temperature, and the amount of hydrogen permeating into the steel is measured by an electrochemical hydrogen permeation method. That is, the 〇1 MNa〇H aqueous solution is filled on the side of the hydrogen detecting surface, and the reference electrode (Ag/AgC1) is attached via a salt bridge, and the non-polishing surface (evaluation surface: non-punching machine contact surface) side is attached. Dropping 〇5 mass%>^(:1 solution, and etching it in the atmosphere at room temperature, so that the potential on the side of the hydrogen detection surface reaches 〇VvsAg/AgC1, at a frequency of i times/day The hydrogen permeation current value was measured for 5 days in a pure water drop under the etched portion, and the hydrogen permeation resistance accompanying the corrosion was evaluated based on the maximum current value on the following basis. As long as 40 Δ, ie, 3⁄4 is sufficient for the purpose of the present invention Furthermore, the test for the formation of '4' of the scale during hot pressing is tested after the surface of the surface is removed by bead blasting. The maximum current value is 1/1 〇 or less of the cold rolled steel sheet △: The maximum current value is more than 1/1G to 1/2 of the cold-rolled steel sheet. The maximum value is less than 1/2 of the cold-rolled steel sheet. The same as the cold-rolled steel sheet. 099136873 201127967 The results are shown in Table 1. Hot pressing property, spot weldability, paint adhesion, and hydrogen permeation resistance of the hot pressing member No. 1 of the present invention Excellent. 099136873 19 201127967 [Id Remark 1 Inventive Example] Inventive Example Inventive Example Inventive Example Inventive Example: Inventive Example | Inventive Example Inventive Example | Inventive Example | Inventive Example 1 Inventive Example | 1 Comparative Example 1 Comparative Example I Comparative Example Comparative Example ±i and Tetrahydrogen Permeability 1 <] 0 〇〇〇〇〇〇〇〇〇〇〇<] <<] XX Paint Adhesion 1 _ 〇〇 〇〇〇〇〇〇〇〇〇〇〇 XX 〇〇〇 spot weldability ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ ◎ 〇〇〇 X ◎ 戚 hot pressing 1 < 3 < 1 〇〇〇 〇〇〇〇〇〇〇〇XXX <] Depth of X Ni diffusion area (Aim) fH »—Η r»H in ο t < ο 〇1 Heating temperature before hot pressing CC) 〇ON 〇Ο 〇〇 ο 〇〇〇〇沄Os 〇00 ο σ\ 〇〇\ 〇〇ο ο 附着 The layer of the surface of the steel sheet before hot pressing constitutes the amount of inorganic compound attached (mg/m2) Ο ο 〇Η 1000 〇Ο 〇Ο 〇*« Η * Η 〇〇〇〇〇〇〇〇§§ 1-H r-1 ο ο ο 4000 〇ο ο #. l-10%S i plated steel plate cold-rolled steel plate melting point CC) Η Η 1—^ 741 1700 ν〇οο 〇〇CO 〇in 741 1700 *«Η r"H 〇fH m Os CN type sodium tetraborate decahydrate tetraborate decahydrate丨Sodium sulphate decahydrate tetrasodium sulphate decahydrate 荸+ 0 calcium hydroxide sodium carbonate sodium fluoride cerium nitrate + 0 tetra-sodium sulphate decahydrate tetraborate decahydrate tetrahydrate sulphate nano ten Hydrate sulphuric acid, zinc chloride, Ni coating, Ni adhesion (mg/m2) 〇〇〇〇1000 1000 1000 3000 3000 10000 50000 〇〇Ο Ο ο ο < 1 type Ni-10%Zn 2 t 6 Φ. (N m inch VO 〇〇 〇 〇 Η Η Η m m m m m m m m m m m m m m m ° ° ° ° ° 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 660 . Fig. 2 is a schematic view showing an electrochemical unit used in the present embodiment. 099136873 21

Claims (1)

201127967 VII. Patent application scope: L A kind of hot-pressed component, which is mixed in the surface layer of the steel plate constituting the component and has a N! attached #1 to 9G_mg/m\Ni diffusion region, and has inorganic on the diffusion region. Compound. 1 2. If you apply for a patent _ the first! The hot-pressing member according to the item, wherein the inorganic substance has a melting point of 500 〜 i 〇〇〇〇 c. σ 3. The hot-pressed member according to claim 1 or 2, wherein the inorganic compound contains an alkali-soluble component. 4. A method for producing a hot-pressed member, which is characterized in that a steel sheet containing a scratch-coating layer and an inorganic compound having a Ni adhesion amount of 10 to 90,000 mg/m 2 is sequentially heated to an Ah metamorphic point on the surface of the steel sheet. ~1200. 5. The method of producing a hot-pressed member according to the fourth aspect of the invention, wherein the inorganic compound is a melting point of 500 to 1000. (Inorganic compound is used.) 6. The method for producing a hot-pressed member according to claim 4 or 5, wherein 'as the above inorganic compound, an inorganic compound containing a soluble component is used. 7. In the scope of claims 4 to 6 A method for producing a hot-pressed member according to any one of the above-mentioned steel sheets is a steel sheet having the following composition: expressed by mass%, containing C: 0.15 to 0.5%, Si: 0.05 to 2.0%, Μη: 0.5 ~3%, Ρ: 〇.ι〇/0 or less, s: 0.05% or less, Α1: 0.1% or less, Ν: 0.01% or less, and the rest contains Fe and unavoidable impurities. 099136873 22 201127967 8. The method for producing a hot-pressed member according to the seventh aspect of the invention, wherein the use of at least one selected from the group consisting of Cr: 0.01 to 1%, 11: 0.2°/. or less, and B: 0.0005 to 0.08% is further expressed by mass%. Steel plate. 9. If applying for a patent A seventh manufacturing method of hot pressing member 8 of which are used in mass%, further contains Sb:. 0.003~0.03% of the steel sheet 09,913,687,323