TW201137130A - High-strength hot-dip galvanized steel sheet with excellent processability and impact resistance and process for producing same - Google Patents

Abstract

Provided is a hot-dip galvanized steel sheet which has a tensile strength TS of 590 MPa or higher and excellent processability and which, even when no strain is introduced thereinto by pressing, highly absorbs energy in a low-strain range up to about 5% and has excellent collision resistance. Also provided is a process for producing the steel sheet. The galvanized steel sheet has a composition which contains, in terms of mass%, 0.04-0.13% C, 0.7-2.3% Si, 0.8-2.0% Mn, up to 0.1% P, up to 0.01% S, and 0.01-0.1% Al, with the remainder comprising iron and incidental impurities, and has a structure which comprises, in terms of areal proportion, at least 75% ferrite phase, at least 1% bainitic ferrite phase, and 1-10% pearlite phase, has a martensite phase content of up to 10% in terms of areal proportion, and satisfies (areal proportion of martensite)/((areal proportion of bainitic ferrite)+(areal proportion of pearlite))=0.6, and in which the ratio of the Mn concentration in the ferrite phase to the Mn concentration in the second phase is 0.70 or above.

Description

201137130 VI. Description of the Invention: [Technical Field of the Invention] Impact Resistance Characteristics for Steel Sheet Use The present invention relates to a high-strength smelting zinc steel sheet which is excellent as an automobile. [Prior Art] In recent years, from the perspective of global environmental protection, the improvement of fuel efficiency of automobiles has become an important issue. Therefore, there is a tendency to use a high strength of the vehicle body material to achieve a thin plate, and the movement of the vehicle body itself is becoming lighter. “The high-strength material of the steel sheet causes the rolling ductility to decrease—the silk processing (10) is low. Therefore, it is expected to combine the material development with W degree and high I. And because of the strain rate of each part when the car collides. The degree of reaching the heart is therefore particularly important in the high-speed range. Moreover, the recent development of the high-tension steel plate for the smelting of the zinc is recorded. In order to ensure the sharpness, the miscibility, and the adhesion of the coating, the alloyed hot-dip galvanized steel sheet which is subjected to heat treatment after plating and which diffuses Fe of the steel sheet into the plating layer is often used. A high-strength steel sheet excellent in both workability and impact absorption resistance is a two-phase structural steel sheet (pp steel sheet) composed of a composite structure of ferrite iron and granulated iron as disclosed in Patent Document 1. However, the original The reason why the DP steel sheet with low drop strength exhibits high impact absorption capacity is that the work hardening by stamping processing is large, and if the processing strain enters, it will be generated in the subsequent baking step. Variable aging results in the strength of the fall 100102078 3 201137130 Significantly improved 'There will be problems such as bending processing and other parts with small heart volume may not be able to absorb enough impact. Jade ^ ^ ^ 疋古麻辔敁 towel u 'DP steel has 10~ In the 30% degree quilting domain, the impact energy absorption capacity is high, and the _ hit characteristic is excellent. Although it is suitable for the part where the front touch material turns into the paving, the part of the absorbing force will be absorbed, but from the side collision site. It is difficult to say that it is sufficient to ensure that the driver is empty. It is difficult to say that it is sufficient to absorb energy in the small strain domain 古I ancient π 曰 支 支 疋Α 专利 专利 ' 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利 专利In the case of the TRIP steel, which has been subjected to the change of the impact resistance characteristics, it has the same problem as the above-mentioned DP steel. [Prior Art Document] [Patent Document] [Patent Document 1] Japanese Patent Laid-Open Publication No. 2003-213369 [Patent Document 2] SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION The object of the present invention is to provide a high strength (tensile strength TS of 590 MPa or more), which is excellent in workability and even In the present invention, the present inventors have been able to introduce a strain in the low strain range up to 5% by press working, and to have a large impact energy resistance, and a method for producing the same. In order to achieve the above-mentioned problems, the high-strength Wei Rong series steel plates, which are excellent in both workability and impact resistance, are well studied. From the viewpoint of steel plate composition and microstructure, it is found that the main phase is the ferrite iron. The two phases contain the structure of the fertile iron, the granulated iron and the granulated iron, and satisfy the area ratio of the granulated iron in the granules/(_the area of the iron granules + the area ratio of the granules of the granules of 0.6), and the iron content in the ferrite When the ratio of Mn concentration in Μη 汉度 to the second phase is set to 〇·7〇 or more, the comparative workability and impact resistance characteristics can be obtained. The improvement of the processability can improve the rolling ductility by utilizing the strengthening of the hardening iron of the fat iron which belongs to the main phase, and the use of the ferrite iron and the bead iron. The hardness difference between the ferrite iron and the hard hemp field is relaxed and the hole expandability is improved. Further, it is generally known that Μη is concentrated in the second phase during hot rolling and annealing, resulting in distribution in the steel, but by setting the coiling temperature during hot rolling to a low temperature, and soaking during annealing When the time is set to be appropriate, the Μη distribution in the steel is made uniform, and the ratio of the Μη concentration in the ferrite-grained iron phase to the Μn concentration ratio in the second phase is set to 0.70 or more, even if no strain is introduced by press working. Up to 5% of the low strain domain, the absorbed energy is still large, which improves the collision resistance. The present invention is constructed on the basis of the above findings. That is, the present invention is as follows. (1) A high-strength hot-dip galvanized steel sheet having excellent workability and impact resistance, and has a composition of: C: 0.04% or more and 0% or less, and Si: 0.7% or more and 2.3% or less, in terms of % by mass, Μη : 0.8% or more and 2.0% or less, Ρ: 0.1% or less, S: 0.01% or less, Ai: 0 01% or more, 〇1% 100102078, 201137130 or less, and the rest are iron and not < impurities to be avoided; The tissue system has an iron content of a ferrite grain of 75% or more, a ferro-grain iron phase of 1<J/Q or more, and a bead iron phase of 1% or more and 1〇°/° or less, depending on the area ratio, and The area ratio of the loose iron phase of Ma Tian is less than 10%; it really satisfies the area ratio of the loose iron in the field / (the area ratio of the iron toughened ferrite + the area of the iron of the bead) S 0.6 ' and the Μ η in the ferrite phase The concentration ratio in the second phase is 0.70 or more. (2) The high-strength molten zinc-zinc steel sheet which is excellent in workability and impact resistance as described in (1), and further, the component composition contains Cr: 0.05% or more and 1.0% or less in terms of % by mass. V : 〇〇〇 5% or more and 〇 5% or less, and Mo: 0.005% or more and 0.5% or less of at least one element selected. (3) A high-strength melting bond steel sheet excellent in workability and impact resistance as described in (1) or (2), wherein the component composition is based on the denier. Bezia/〇计' contains from the top and G. under the chest, Nb: (10)% or more, B: (10) 嶋 or more, and (4) or less, Ni: 〇 peach or more and i 〇% or less, Cu: 0.05% or more Select at least ι elements from 〇% below. Injury ^如·^(7) 任任 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖 赖In addition, 5% or less of the above-mentioned percentages and 0. Weicho chooses at least the elements of the species. (5) As in (1) to (4), the towel is a high-resistance sufficiency, which is more advanced, and further ==100102078 6 201137130 by mass %' containing from Ta: 〇. 001% or more and 〇〇1〇% or less, §η: 0.002% or more and 0.2% or less of at least one element selected. (6) The high-strength hot-dip galvanized steel sheet excellent in workability and impact resistance as described in any one of items (1) to (5), wherein, further, the component composition is based on the summer %§10' containing Sb: 0.002% Above and below 2%. (7) A method for producing a high-strength smelting zinc-zinc steel sheet having excellent workability and impact resistance characteristics, wherein the steel preform having the composition of any one of the items (1) to (6) is subjected to hot rolling, and then 300. (: The above and 57 〇. The hot-rolled sheet obtained by coiling at the following temperature is pickled, or further cold-rolled, and then, in the temperature range of 750 to 900 ° C, according to t: holding time (8), after the conditions of the following formula are applied, 15 ^ 47.6xlO", 0/exp(-27〇16/(T+273)) T: annealing temperature (°C), after cooling, according to 450~550° The temperature domain of C is maintained for 10 to 200 s, followed by a molten plating, or further in the range of 500 to 600. (In the temperature range, according to Tave: average holding temperature (°C) and th: holding time (5)) The alloying treatment of galvanizing is carried out under the conditions of the formula; 0.45 ^ exp [200 / (400 - Tave)] xln (th) ^ 1.0. (Effect of the invention) According to the present invention, excellent workability can be obtained, and even if it is not subjected to press working The strain is introduced until the absorption energy of the low strain range of 5% is still large, and the high-strength hot-dip galvanized steel sheet with excellent impact resistance can take into consideration the light weight of the automobile and the collision safety improvement of the f 100102078 7 201137130 The high performance of the high performance is greatly enhanced. [Embodiment] The following 'specification of the present invention First, the reason for limiting the steel component composition of the present invention to the above range will be described. The "%" of the relevant component means "% by mass" unless otherwise stated. C · 〇·04 % or more and 0.13% or less C is an element that stabilizes the Worthite iron because it is easy to form a phase other than the ferrite iron. Therefore, it is an essential element for the increase in the strength of the steel sheet. However, it is still difficult to ensure the required strength. Conversely, if the amount of C exceeds 0.13%, the iron phase of the ferrite is reduced, the processing of the steel sheet is reduced, and the hardening of the welded portion and the heat-affected portion is marked. From this point of view, the amount of C is set to 〇·〇4. /. or more and 〇.13% or less. 8^〇^% or more and 2.3% or less

Sl is a ferrite-based iron-forming element and is also an element that is effective for solid solution strengthening. In order to improve the balance between strength and rolling ductility, and to ensure the hardness of ferrite, it is necessary to add more than 7%. However, if more than 2% of the excess is caused by red rust, etc., the surface properties are deteriorated, and plating adhesion and adhesion are deteriorated. Therefore, (4) is set to 〇 7% or more and 2 3% to T. Preferably, it is U% or more and less than 1.8%. 100102078 201137130 Μη : 0.8〇/〇 and above 2.2/. The following dishes 11 are effective elements of _. And it belongs to the element that makes the iron core stable, and the adjustment of the fraction of the second phase is an essential element. Therefore, Mn must be added up to 〇.8〇/. the above. On the other hand, if excessive addition exceeds 2%, the area ratio of the granulated iron in the second phase increases, and the stretch flangeability decreases. Therefore, the Mn system is set to be 0.8% or more and 2.0% or less. Better! 〇% or more and below. p : 0.1% or less 0 If the effective element of the P-based steel is excessively added, if it is excessively added in excess of 0.1%, embrittlement is caused by segregation at the grain boundary, and the impact resistance is deteriorated. Further, if it exceeds 〇.1%', the alloying speed is greatly delayed. Therefore, the P system is set to 〇 1% or less. s : 0.01% or less ^ will become a material such as Mns, which will cause deterioration of impact resistance and breakage of the metal flow in the joint. Therefore, it is preferable to reduce it as much as possible. 0.01% or less. A1 · 0.01% or more and 〇 1% or less The deodorizer is an effective element for the cleanliness of steel, and it is added in the deoxidation step. Here, if the A1 amount is less than the read %, the addition effect will be deteriorated, so the lower limit is set to G.G1%. However, the addition of D in A1 deteriorates the quality of the flat embryo at the time of steel making. Therefore, the surplus is less than 1%. According to the invention, the composition of the above-mentioned age is the basic composition of _02078 201137130, and the rest is composed of iron and unavoidable impurities, but it may be appropriately selected from the following elements in combination with the desired characteristics. Kind of elements.

Cr. 0.05% or more and 1.0% or less, V: 0.005% or more and 〇 5% or less, and Mo: 0.005% or more and 0.5% or less. Cr, V, and Mo are effective elements for improving hardenability and steel strengthening. This effect is obtained by Cr: 0.05% or more, V: 〇·〇〇 5% or more, and Mo: 0.005% or more. However, if excessive addition exceeds Cr: i.〇〇/0, V: 0.5%, and Mo: 0.5%, the fraction of the second phase may become excessively large, which may cause a decrease in workability. Therefore, when these elements are added, the amounts are respectively set to be Cr: 0.05% or more and 1. 〇〇/0 or less, v: 〇〇〇5% or more and 〇5% or less, and Mo: 0.005% or more and 〇. 5〇/0 or less. Further, one or more elements selected from the group consisting of Ti, Nb, B, Ni, and Cu described below may be contained.

Ti: 0.01% or more and ο.ρ/. Hereinafter, Nb: 〇〇1% or more and 〇1% or less Ti and Nb are effective for precipitation strengthening of steel, and the effect is 0.01% or more, respectively, to obtain 'if it is within the scope of the present invention, it may be used for Steel reinforcement. However, if it exceeds 〇1%, the workability will decrease. Therefore, when Ti and Nb are added, the amount of addition is 〇〇1% or more and 0.1% or less', and Nb is set to 0.01% or more and 〇1% or less. B: 0.0003% or more and 〇 〇〇 5〇% or less The B system has a function of suppressing the formation/growth of the ferrite iron from the Worthfield iron grain boundary, and thus can be added as needed. This effect is more than 3% to get 100102078 201137130. However, if it exceeds 0.0050%, the workability will decrease. Therefore, when B is added, it is set to 0.0003% or more and 0.0050% or less.

Ni: 0.05% or more and 1.0% or less, Cu: 0.05% or more and 1.0% or less

The effective elements strengthened by Ni and Cu-based steels may be used for reinforcement of steel in the range specified by the present invention. In order to obtain these effects, it is necessary to achieve 0.05% or more. On the other hand, when both Ni and Cu are added in excess of 1.0%, the workability of the steel sheet is lowered. Therefore, when Ni or Cu is added, the amount of addition is set to 0.05% or more and 1.0% or less, respectively. Further, one or more elements selected from the following Ca and REM may be contained.

Ca : 0.001% or more and 0.005% or less, reM : 0.001% or more and 0.005% or less

Ca and REM are effective elements for spheroidizing the shape of sulfides and improving the adverse effects of sulfides on hole expandability. In order to achieve this effect, it must be 0.001% or more. However, an excess of more than 00 5% will cause an increase in inclusions, etc., resulting in surface and internal defects. Therefore, when Ca is added, the amount of addition is 0.001% or more and 0. 005% or less. Further, one or more elements selected from the following Ta and Sn may be contained.

Ta : 0.001 to 0.010%, Sn: 0.002 to 0.2%

The Ta-based alloys, like Ti and Nb, form alloy carbides and alloyed nitrogen carbides, which not only contribute to high-strength, but also form a solid solution in Nb carbides and Nb-nitrogen carbides, such as Complex s 100102078, 201137130, Nb, Ta) (C, N) The precipitated product 'significantly inhibits the coarsening of the precipitate, and has an effect of making the contribution to the strength stable by precipitation strengthening. Therefore, when 仏 I 〃 3 is added, it is preferable to set it to 0.001% or more. However, when the excess is added, not only the above-mentioned precipitate stabilization effect is saturated, but also the alloy cost is increased. Therefore, when Ta is added, the content thereof is preferably set to 0 or less. From the viewpoint of suppressing the nitriding, oxidation, or decarburization of the surface of the steel sheet by the oxidation of the steel sheet, the 2 series can be added:::: This kind of nitriding and oxidation can be prevented. The diarrhea and enamel on the surface of the steel sheet improve fatigue characteristics and aging resistance. In the case of adding Sn from the inhibition of oD, the content of Sn is preferably set to = upper 'right than G. 2 °, which will result in a decrease in the secret. Therefore, it is preferable to set the content below 〇.2%. . It may further contain the following Sb.

Sb: 0.002-0.2% When the same is true for Sn, the decarburization of the surface layer 1 (10) from the surface of the steel sheet caused by the nitriding of the steel sheet is suppressed. By suppressing such nitriding, oxidation, good workability and aging resistance, and suppressing nitriding and oxidation, when Sb is added, its content is low, because if it exceeds _, it will lead to a secret drop. It is good to set the content below G.2%. 100102078 12 201137130 Next, the steel structure will be explained. Area ratio of ferrite grain iron phase: 75% or more For the month t to ensure good rolling ductility, the ferrite-iron phase ratio must be more than 75%. The area ratio of the tough ferrite grain iron phase: 1〇/. The above is to ensure good hole expansion for the month b, that is, to alleviate the hardness difference between the soft ferrite iron and the hard Ma Tianzheng iron, and the area ratio of the toughened ferrite iron phase must be more than 1%. Area ratio of the bead iron phase: 1% or more and 1% by mass or less In order to ensure good hole expandability, the area ratio of the bead iron phase is set to be 1% or more. If the area ratio of the bead iron phase exceeds 10%, the rolling ductility (TSXEL) will decrease. Therefore, the area ratio of the bead iron phase is set to be 1% or more and 10% or less. Area ratio of the iron phase of Ma Tian: 10% or less The area ratio of the loose iron phase of the right Ma Tian is more than 10%. The decrease in stretch flangeability tends to be obvious. Therefore, the area ratio of the granulated iron phase is set to be 10% or less. The area ratio of the loose iron in Ma Tian / (the area ratio of the iron toughened ferrite + the area ratio of the bead iron) S0.6 'The difference in strength between the Ma Tian scattered iron system and the ferrite iron is large, which will reduce the stretch flangeability. By coexisting with the toughened ferrite iron and the bead iron, and setting the area ratio of the granulated iron / (the toughened ferrite iron area ratio + the bead iron area ratio) S 0.6, it is possible to suppress the cause of the field The resulting hole expansion is reduced. Therefore, it is set as the area ratio of the granulated iron area / (the area ratio of the toughened ferrite grain to the area of the iron of the bead iron) of $0.6. 100102078 13 201137130 In addition, in addition to ferrite iron, tough ferrite iron, bead iron, and Ma Tian loose iron, there are still cases of carbides such as residual Worth iron, tempered granulated iron, and carbon carbide. 'But if the above-mentioned area ratio of ferrite iron, granule iron, bead iron, and 麻田政铁 is satisfied, the object of the present invention can be achieved. Further, in the present invention, the "area ratio of ferrite iron, tough ferrite iron, bead iron, and 麻田政铁" means the ratio of the area of each phase in the observed area. The microstructure is applied to 1/4 of the thickness of the steel sheet in the rolling direction section, and then etched using 3% Nital, and then observed using a scanning electron microscope at a magnification of 5000 times, and using Media cybemedcs. Image-Pro finds the area ratio of each phase. At this time, since the distinction between the Ma Tian loose iron and the residual Worth iron is difficult, the obtained hot-dip galvanized steel sheet is subjected to tempering treatment for 20 hours (rc), and then, according to the above method, the rolling direction of the steel sheet is observed. The area ratio of the parallel plate thickness profile and the gas obtained by the above method is regarded as the "area ratio of the granulated iron phase of the Matian". The steel plate is polished to a quarter surface in the thickness direction, and the diffraction ray intensity of the 1/4 surface of the plate thickness can be obtained. At this time, the incident X-ray system uses a CoKa line and is directed to the residual Worthfield. The {111}, {200}, {220}, {311} planes of the iron phase are combined with the peak intensity of the {11〇}, {200}, and {211} planes of the ferrite phase to obtain the intensity ratio. And the average value of these is regarded as "the content of the residual Worthite iron phase", and the content is regarded as the "area ratio of the residual Worthite iron." 100102078 】4 201137130 Μη concentration, Μη concentration ratio in the second phase (Mn concentration in the ferrite phase iron phase / Μη concentration in the second phase) is 0.70 or more By forming the Μη distribution in the steel evenly, even if there is no strain introduced by the press working, the absorption energy in the low strain range up to 5% is still large, and the collision resistance property can be improved by the ferrite grain in the iron phase. This effect can be obtained by setting the concentration of Μη and the concentration of Μη in the second phase to 〇.7〇 or more. Therefore, the ratio of Μη in the ferrite phase and the Μn concentration in the second phase are set to The steel material adjusted to the above-mentioned component composition is melted by a converter or the like, and a flat embryo is formed by a continuous casting method or the like. The steel blank is hot rolled to form a hot rolled steel sheet. The hot-rolled steel sheet is subjected to pickling or further cold rolling to form a cold-rolled steel sheet. The acid-washed hot-rolled steel sheet or cold-rolled steel sheet is continuously annealed, and then subjected to hot-dip galvanizing treatment or further Zinc-plated alloying treatment. The reasons for limitation of each step will be described. [Hot-rolling conditions] Coiling temperature: 300 ° C or more and 570. (: The following coiling temperature after hot rolling exceeds 570. (:, in After the roll, it will be promoted The division of Mn into the second phase causes the final tissue to be more difficult to set the concentration of the ferrite in the ferrite phase to the concentration of the niobium in the second phase to be more than 〇.7〇. Also, if the coiling temperature is not When the temperature is 30 (TC, the shape of the hot-rolled sheet is deteriorated, or the strength of the hot-rolled sheet is excessively increased), it is difficult to perform cold rolling. & The coiling temperature is set to 100102078 15 201137130 300 ° C or more and 570 ° C or less. [Continuous Annealing Conditions] 乂 is annealed in the temperature range of 750 to 900 ° C according to the conditions of the following formula: 15 ^ t ^ 47.6x 1 〇-10/exp(-27016/(T+273)) t : Time (s) T : Annealing temperature (° When the annealing temperature is less than 750 ° C, or the holding (annealing) time is less than 15 s, the formation of Worth iron during annealing is insufficient, resulting in failure to ensure annealing cooling The necessary amount of low temperature metamorphic phase. On the other hand, if the annealing temperature exceeds 9 〇〇t:, the Worth iron in the annealing will increase remarkably, and the amount of ferrite iron which is necessary after annealing and cooling cannot be ensured. Moreover, if the holding time exceeds 47.6xl01G/exp(-27016/(T+273)) seconds, the concentration of Μη on the iron phase of the Vostian will be excessively performed during annealing, which makes it difficult to finally form the ferrite phase. The Μη concentration in the middle and the Μη concentration ratio in the second phase are set to 0.70 or more. After annealing, it is cooled and kept at a temperature of 450 to 550 ° C for 10 to 200 s. When the temperature is maintained above 55 CTC, or the holding time is less than 1 〇s, since the toughened iron metamorphosis is not promoted, the toughened ferrite iron is hardly obtained, and thus the desired hole expandability cannot be obtained. In addition, when the temperature is less than 45 〇ΐ, or the holding time exceeds 20 Gs, the majority of the second phase will become HI 41⁄4 1 which is produced by the change of the metamorphosis of the ferrocene. Iron, which leads to the inability to obtain the (four) bead __ rate' and the hard (four) read iron area ratio will increase, resulting in poor hole expandability and material stability. 100102078 16 201137130 After the above holding is carried out, it is easy to carry out the rust-preventing ability in actual use, and the surface is subjected to hot-dip galvanizing treatment. In order to ensure the punchability, the spot weldability, and the adhesion of the coating, an alloyed hot-dip galvanized steel sheet which is heat-treated after plating and which causes the steel sheet to diffuse into the ore layer is often used. In the production of the alloyed hot-dip galvanized steel sheet, after the hot-dip galvanizing, the alloying treatment was carried out under the following conditions. [Alloying treatment conditions] In 500 to 60 (TC temperature range, Tave: average holding temperature (.〇, ratio: holding time (s), according to the following formula: 0.45 Sexp [200/(400-Tave)] xln (th) The condition of $1'〇 is applied to the alloying of the plating layer. In addition, 'exp(X) and 1η(χ) respectively represent the exponential function of X and the natural logarithm. The alloying treatment of the plating layer is When the appropriate Fe% is obtained in the plating layer, it is set in the range of 500 to 600 ° C. When exp[200/(400-Tave)]xln(th) is less than 0.45, there will be more in the final structure. The existence of loose iron in Ma Tian causes the above-mentioned hard ram field loose iron to be adjacent to the soft ferrite iron, resulting in a large hardness difference between the heterophases, resulting in a decrease in hole expandability. When exp[200/(400-Tave)]xln(th) exceeds At 1.0, the untransformed Worthite iron is almost always metamorphosed into carbon carbide or bead iron, and as a result, the required strength and rolling ductility are not obtained. Further, in the series of heat treatments of the manufacturing method of the present invention, temperature

S 100102078 17 In the range of 201137130, it is not necessary to maintain the temperature. If it is within the specified range, the gist of the present invention will not be impaired. Moreover, if the heat history can be satisfied, the steel plate may be subjected to heat treatment according to any equipment. In addition to this, it is also within the scope of the present invention to perform the temper rolling of the steel sheet of the present invention after the heat treatment to perform the shape of the shape. Further, the present invention is a case where the steel material is manufactured by various steps such as ordinary steel making, casting, hot rolling, etc., but it may be manufactured by, for example, thin-plate casting or the like, and some or all of the hot rolling steps are omitted. The other production method is not particularly limited, and a preferred example is as follows: ✓1, ° [Casting conditions] The steel germ system used is a macroscopic segregation of the component, and it is preferably produced by a continuous casting method. Manufactured by the block method and the thin blank casting method. In addition, in addition to the conventional method of cooling to room temperature and then heating again after manufacturing the steel embryo, it is not cooled to room temperature, but is inserted into the heating furnace according to the state of the hot sheet, or is slightly protected. After the heat is applied, the direct rolling and rolling, direct rolling and other energy-saving processes can be applied without any problem. [Hot rolling conditions] Flat embryo heating temperature: 1100 °c or more Flat embryo heating temperature is preferably low temperature heating in terms of energy, but if the heating temperature is less than 〇〇 ° ° C, there will be insufficient carbide solidification. Solubility, or increased risk of failure during hot rolling due to an increase in rolling load, occurs. In addition, since the increase in the skin loss (scalel 〇ss) is caused by the increase in the amount of oxidation, the heating temperature for the embryo is preferably set to the following. Further, from the viewpoint of preventing the failure at the time of hot rolling even if the heating temperature of the slab is lowered, it is also possible to use a heater which heats the sheet material. Finishing temperature: If the finishing temperature of Ar3 is above the metamorphic point, if the end temperature of the fine milk is not full _ metamorphic point, 〇 and ^ will be formed in the Zhayan, resulting in the formation of banded structure in the steel plate. The banded structure will still be after cold rolling and after annealing. Residues may occur as a cause of anisotropy in material properties or a decrease in workability. Therefore, the finishing temperature is preferably set to be above A stagnation point. Further, in the hot rolling step of the present invention, in order to reduce the rolling load during hot rolling, it is also possible to carry out the rolling rolling of the part or the whole of the finish rolling. It is also effective from the viewpoint of uniformizing the shape of the steel sheet and homogenizing the material f. In addition, it is preferable to set the friction coefficient of the lubrication rolling delay to be within the range of Q25 to (4). Further, it is preferable to perform a continuous rolling process in which the preceding and succeeding strips are joined to each other and the finish rolling is continuously performed. It is also preferable from the viewpoint of the stability of the hot rolling operation by using the continuous rolling process. Hall [Cold Rolling Condition] Next, when cold milk is applied, it is preferable to remove the iron oxide scale on the surface of the hot-rolled steel sheet by the pickling material, and then supply it to the cold-rolled steel sheet having a predetermined thickness. Here, there are no particular restrictions on the pickling conditions and the cold rolling conditions, and only the usual method can be used. The cold rolling reduction ratio is preferably set to 4% by weight or more.乂100102078,Λ201137130 [Metal galvanizing conditions] The coating treatment is carried out by immersing the steel sheet in a plating bath at a bath temperature of 440 to 500 ° C using a plating bath in which 8 to 0.18% of A1 is dissolved. The amount of adhesion is adjusted by an air brush method or the like. Further, the steel sheet subjected to the hot-dip galvanizing treatment may be subjected to adjustment of shape correction, surface roughness, or the like, and may be subjected to temper rolling. Moreover, there is no problem even if a treatment such as resin or grease coating or various coatings is applied. [Examples] Steel having the composition shown in Table 1 and having Fe and unavoidable impurities (N, unavoidable impurities in Table 1) was melted in a converter and cast by a continuous casting method. sheet. 100102078 20 201137130

Remarks invention steel invention steel invention steel invention steel | invention steel | invention steel invention steel invention steel invention steel | invention steel | 1 invention steel I comparative steel | comparative steel | 丨 comparative steel I | comparative steel | | comparative steel | Steel invented steel Invented steel chemical composition (mass%) 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Sb : 0.007 Ta,Sn 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Ta : 0.005 Sn : 0.007 Ta : 0.008 1 Ca, REM 1 1 1 1 1 1 1 1 1 Ca : 0.002 REM : 0.002 1 1 1 1 1 1 1 1 1 Ti, Nb, B, Ni, Cu 1 1 1 1 Ti : 0.04 Nb : 0.03 Ti : 0.015, B : 0.0010 m 〇Cu : 0.4, Ni : 0.2 1 1 1 1 1 1 1 Nb : 0.02 Nb : 0.04 1 1 Cr, V, Mo 1 Cr : 0.2 Y : 0.05 CN 〇〇1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0.0025 0.0042 0.0033 0.0045 〇·〇_ 0.0041 | 0.0029 | | 0.0039 | 0.0042 | | 0.0020 I 1 0.0035 1 | 0.0036 1 0.0040 0.0025 0.0038 0.0031 0.0035 0.0042 0.0028 0.0031 0.03 0.04 0.03 0.04 0.03 0.03 0.04 "0.05 "0.03 0.02 "0.031 "0.03 Γ〇.03 "0.03 "0.03 0.04 0.03 "0.04 0.04 (0.03 0.0030 0.0025 0.0040 0.0 028 0.0014 0.0012 0.0008 0.0035 1 0.0020 | | 0.0031 I 1 0.0028 | 0.0015 | 0.0015 0.0015 0.0009 0.0012 0.0021 0.0024 0.0015 0.0010 0.010 0.010 0.010 0.009 0.008 0.012 0.012 0.009 0.011 0.008 | | 0.012 I 1 0.014 | o.oio 0.010 0.012 0.008 0.008 0.009 0.007 0.010 Mn vq r"H 00 vq H 00 CN rn v〇in 00 VO v〇c> ΓΠ cs VO inch · <N 00 cs fH r·^ oo 1-H o (N <N y—4 O) tH CN CN iTi CO ITi 〇cs oo fH υ 0.06 0.10 0.08 0.05 0.07 0.10 0.12 0.08 |0.0』 0 别 0.07 0.03 0.15 0.07 0.07 0.09 0.08 0.10 0.07 0.09 < m UQ o HH o CL, a Pi OO H -SZOSIOOI 15 The conditions shown in 201137130 2 and Table 3 are purely plate-thick steel plates, and - 23mm λλ^α, some of which are hot-rolled into plate thicknesses, .4 steel plates, and then directly subjected to acid annealing to provide annealing.耆, the cold-rolled steel sheet L-steel was subjected to annealing and plating treatment using conditions of the combination of Wei Ronglin and ==2 and Table 3. In the plating, the § is 35~45g/m2 per side. = Investigation was made on the microscopic_, tensile properties, (f) flangeability and impact resistance properties obtained. The results are shown in Tables 4 and 5. Further, the microstructure is observed with respect to the thickness of the steel sheet in the section of the rolling direction of the steel sheet by using a scanning electron microscope at a magnification of 5 times the magnification, and the area ratio of each phase is obtained by the above method. The ferrogranular iron phase and the second phase ten Μη concentration were measured by line analysis of Μη by using ΕΡΜΑμ.ιμιη intervals. The average value of the Μη concentration of each particle is regarded as the Μη concentration of the particle, and the iron particle phase and the second phase of each of the 10 particles are measured, and the average value thereof is regarded as the ferrogranular iron phase and the Μη concentration of the second phase. . The workability is evaluated in terms of rolling ductility and hole expandability (stretch flangeability). For the rolling property, the JIS No. 5 test piece taken from the direction perpendicular to the rolling direction of the unprocessed steel sheet was subjected to a tensile test at a strain rate i 〇 -3 / s, and TS (tensile strength) and EL (total elongation) were measured. Rate), the case of TSxELg 19000 MPa·% was judged as "good". 100102078 22 201137130 The stretch flangeability is implemented according to the Japan Iron and Steel Federation specification JFST1〇〇i. After the obtained steel sheet is cut into l〇〇mmx100mm, the thickness of the plate is 2% or more depending on the gap of 12%±1%, and the thickness of the plate is less than 2Gmm according to the gap of 12%±2%, and the punching hole is 10mm hole, and then Using a mold that is kneaded in a 75-inch state, 6 〇 is placed in a state where the crease is pressed by a force of 9 ton. The conical punch was pressed into the hole, and the diameter of the hole at which the crack occurred was determined. The ultimate hole expansion ratio λ (%) was obtained from the following formula, and the tensile flangeability evaluation was performed from the value of the ultimate hole expansion ratio. The ultimate hole expansion ratio λ(%)={(ϋ"D〇)/D〇}xl〇0 where 'Df is the hole diameter (mm) at which the crack occurs, and the initial diameter (mm) of the D〇 system. In the present invention The case where λ^70 (%) was judged to be good. The impact absorption characteristic was obtained from a direction perpendicular to the rolling direction of the unprocessed steel sheet to a test piece having a width of 5 mm and a length of 7 mm in the parallel portion, and was obtained until the strain rate was 2000/ s The absorbed energy of the strain in the tensile test (see Iron and Steel, Vol. 83 (1997), p. 748), and the impact absorption characteristics are evaluated according to the ratio of absorbed energy to static TS (AE/TS). In addition, the absorbed energy is obtained by integrating the stress-true strain curve according to the range of 0 to 5% of the variable. 100102078 23

—sso- 201137130 [s] Remarks Inventive Example of Invention Invention Example of Invention Invention Example Invention Example Invention Example Invention Example Invention Example Invention Example $ f Alloying exp[200/(400-Tavs)]xln(th) 0.79 0.73 0.92 0.82 0.71 0.64 0.82 1 0.73 0.64 0.79 0.85 Retention time th(s) un (N 〇 (Ν average hold; 跋Tave〇C) 550 Ο VO κη 沄Ο 沄Ο 沄Ο m ο 〇m to Ο After cooling until the plating bath is immersed Pre-hold time (8) 〇ο ο ο ο § Ang Ο 1 After cooling until the average holding temperature before the key bath is dipped CC) 480 〇ο 沄ο Ο o inch ο Ο 〇s Ο 47.6x10'10/exp (- 27016/(T+273)) 258 m ro νο 00 00 1086 g Μ Ό Ό Ό 1—^ Ό ν〇 Hold time (8) 〇ο 沄〇ο g § 1 Annealing temperature 820 820 〇ο οο ο 00 ο 00 o ο 00 ο 〇Ο ΟΟ Ο οο Cold rolled with or without cups, cups, cups, cups, cups, cups, cups, hot rolling conditions, 1 I coiling temperature, CC) 丨 430 | 〇ο ο ο ο ο ο 00 m 〇00 C^i ο ο ο ο 〇 ο CN ο 1 : Finishing temperature CC) 910 | 〇5; ο Os 00 ο Ον 00 ο CM Os 〇\ g 00 g 00 in ο Γ Qs ο m Ον heating temperature CC) 1250 1250 1250 1250 Γ 1250 \ 1250 1 1 1250 1 1250 | 1250 1 1250 1 1250 \Ά1 〇ζΛ Η < 02 U steel plate ν〇00 mo 5 3 5 4 SAOSlool s 20 one inch 硌a no p—I»r· l?\ inch c> d empty r〇mc? d Ϊ ii S ir>c> oh Remark 1 i >fe i[ aJ si recorded λ3 if ? ±iaa £ i lost i blue ¥ Λ3 Λ3 λ3 彰 Jj £ lT> m 〇d lankan jD id .»» 〇c> —— CS 00 <〇in od ir><〇O dod <〇in 〇c5 〇〇d K oo si m S 〇 〇 j j j j j 63 Inch 3 C> dt 〇d < ΦΊ ^7 ω 倒 ο ν〇cn O 〇〇 (N [ΤΙ m cs -I - OO r〇oi— cn ΚΠ mo〇?; P; Ρ; 00 Ρ; _ (Ν Ρ; t: inch inch o (N m Os Ό 1/Ί r〇— oo mr〇v〇〇〇r〇m 1 ir> 00 vn ... mm rH OO ΓΛ OO 5 1 ir>v£> in m 1 inch^ rt Nw/ ΓΛ OS ψ· Η Γ〇 ν ? CN σ> «—H οο ο ο 宕ο 00 f—Η μ CN ΟΟ σ^ v〇宕oo d Oj r*H m CN oc 00 O Ό (N v〇s 卜 s S 00 f-1 00 jn <—· 〇<〇卜卜J s CN inch S 00 r~H CN ΟΟ 2 \ο ο 卜卜m s tN m oo 1-H md〇<〇1-HO CTN ί s ON _ ro 寸 CN δ ι—Η 异(Ν ΓΛ Ο Γ〇Ο | s (N r〇m 宕v£> 汔s1 ns 00 1 . 1 1 1 cs oo different rl ri o CS On jr; 00 ON i Cs vn σΝ CN v〇ΓΟ Γ〇Γ〇ΓΟ 〇S (Ν \η S (Ν m 〇ι in r3 ο l/Ί cn g in (N ΓΛ r·^ »/") ON iTi ro inch S r ^ cn sf〇osm 〇s CO Ό m 00 U-> o PO s Ό m ΓΛ cs ΓΟ SS m ΓΛ oc sm (N o v> fn f~H Ό ΓΛ 00 δ m cs CO v£> Pi om Stem smm rn v〇IT) uo σ\ IT) CN 〇戚Μ \\^ Si 00 卜 c> S c5 JTJ Ο I 窆ο d 1 c5 0.84 I dd 〇> o Os do^ o 0.82 CN 00 c5 ( 00 00 c5 〇〇〇so 1 0.82 <〇v〇d 〇s 〇ir> m Ό Ο rO 〇o OO o in oo o in r-of-H OO o Stem O po Other phases; I 1 I ΚΚ! 寒j 5 1 1 i 翁5 1 1 1 1 1 1 1 Move 1 1 1 Bu SB 1 1 1 I 1 1 1 1 1 1 1 c- Move? έ <〇mdoo Ο CS ο 1 卜d 〇1 〇0.20 o 1.00 1 0.55 | 〇o CN 0.25 1 in d Ο 〇d inch τ—Η ο ro ΓΛ d 沄o 〇d ri ο 〇沄c5 oo c> ooo ^T) 宕c5 so 敏^ ie uo οο σ\ v〇Ο r- o O VO CN II iT&gt ; m ro inch inch < inch inch inch m inch CN cs CN ^1 Ol W5 Gangan··— ο o Ο o (N o VO o rn Ό Ο inch <Ν inch inch m \r\ inch i〇CN 卜 OO CN 11 m <〇变微铁1 m 00 yn v〇〇〇J 卜ο CN 00 Ο o r-^ VO o. VO m \T) m VO <〇in inch 00 r^ IT) must O ν 〇m CN <η <N mr«H rH Ol or—' Mt <Ν 00 »〇〇\ VD 00 On m CO OO 00 00 00 7Γ m 00 m 00 ro 00 oo m 00 S τ $ -) 00 ~a (N 00 _ oo 00 — m 00 -M m 00 卜 m 00 > ss fly U^i 00 1 lmsa 1 3 Ξ B 綦-c fH -— i two Γ〇 PQ inch ^ OU oo Ov U o is called EJ rj W r〇»-H inch □ Ι Ι Ι-Η V. 00 r-' J ON CN CN <N r〇CN CN CM r*H m P? mr〇(钋无喵镣怼Birthday + 钋 洄 洄 洄^ 铋 铋 / / / / 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 喵辕 37 37 37 37 37 37 37 37 37 37 37 37 37 Example I Inventive Example I ±i AE/TS 0.058 0.053 ! 0.055 0.059 0.055 0.053 0.057 0.061 0.056 0.058 0.055 up to 5% absorption energy AE(MJ/m3) Ο m <N m OS m ο mmmm /−S 's— ✓ 〇〇 (N OO § 00 oo oo m oo g 00 so TSxEL (MPa · %) 20670 21248 19648 19734 21630 | \ 21744 | 19068 19740 1 19520 I 20064 | 20825 | wg (N cn <N m cn CO m 00 CN (N CO cn cn in CO h| 〇 00 00 oo os oo S OO v〇OO VO 〇 00 〇 Microstructure Ί ^ City: 铡 Green 1 0.80 1_ 0.74 0.78 0.80 0.75 0.72 0.78 0.82 0.80 0.78 0.77 Other phases 1 1 1 I residual γ I 1 1 1 I residual γ 1 1 1 1 M/(B+P) 0.25 1 | 0.25 | | 0.13 I 1 0.29 1 | 0.44 | | 0.50 [0.40 I [0.40 1 Γ 〇.33 [0.30 o Bead iron P(°/〇) Inch CM <N ^T) VO Ma Tian loose iron M (%) m (N CN <N inch inch CN cn Toughened ferrite iron B (%) 〇 〇in Os inch ro inch m inch cn fertilizer Iron F (%) oo (N OO OO 00 00 ON OO 00 00 g 1 α Pi X/l H < CQ U steel plate m \〇P: 00 Os m 〇 inch rn (铢乐《黎为#+铢嬷"瓌4 翱 翱 翱 跻 跻 翱 跻 ( ( ( ( ( ( ( ( ( ( ( ( 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 2011 37 2011 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 According to the strain rate of 2000/s until the strain 5%, the ratio of absorbed energy to static TS (AE/TS) is 0.050 or more, and small strain range processing at high strain speed can be obtained, which has high impact resistance. Strength alloyed hot-dip galvanized steel sheet. On the other hand, in the comparative example, since the AE/TS is less than 0.050, the high strain resistance of the small strain range processing at a high strain rate is inferior, and at least one of the rolling property and the stretch flangeability is inferior. (Industrial Applicability) The high-strength hot-dip galvanized steel sheet according to the present invention is excellent in workability and excellent in ==. The high-strength smelting ore plate of the present invention is not only applicable to the steel plate of the second == collision portion but also to the side impact steel electrode and can also be used as an additional plate for bending. Steel used in smaller parts 100102078 28

Claims (1)

201137130 VII. Patent application scope: 1. - Kind of edifying (4) High strength with excellent impact characteristics (4) Mineral steel plate' is characterized in that the composition of the component is based on the amount of f%, including c: more than 3% and less than 3%. , Si : 〇 7% or more and 2 3% or less, 〇 8% or more and 2.0% or less, p : G 1% or less, s : G Q1% or less, n (four) or more and 〇. 1% or less, and the rest are iron And an unavoidable impurity; the microstructure is 75% or more of the ferrite phase iron phase, 1% or more of the toughened ferrite iron phase, and 1% or more and 1% or less of the bead iron phase according to the area ratio, And the area ratio of the iron matrix of Matian is less than 10%; and the area ratio of the iron field of the Matian/(the area of the iron content of the toughened fertilizer + the area of the iron of the bead) is 0.66, and the concentration of Mn in the ferrite phase is the second. The Mn concentration ratio in the phase is 0.70 or more. 2. The high-strength molten zinc-zinc steel sheet excellent in workability and impact resistance according to the first paragraph of the patent application's component composition is further contained in terms of % by mass: Cr: 0.05% or more and 1.0% or less, V: 0.005 An element of at least one selected from the group consisting of % or more and 0.5% or less and Mo: 0.005% or more and 〇 5% or less. 3. A high-strength molten galvanized steel sheet excellent in workability and impact resistance according to the first or second aspect of the patent application, wherein the component composition further contains Ti: 〇.〇i% or more and 〇1 in terms of mass% % or less, Nb: 〇〇1% or more and 〇1〇/〇 or less, B: 0.0003% or more and 0.0050% or less, Ni: 0.05% or more and 1.0% or less, and Cu: 0.05% or more and 1.0% or less. At least one element of 100102078 29 201137130. 4. In the case of high-strength miscellaneous (4) items with excellent characteristics of patent application, the processability and impact resistance of 0/..^' and zinc steel plate, wherein the composition of the composition is further contained in terms of mass/〇: Υϋ1〇 or more and 0.005% or less, and at least one element selected from REM: 0.001/〇 or more and 0 005〇/乂. 5. If the application is in the range of items 1 to 4, the processing and impact resistance characteristics are excellent. (4) Niu Rong, where the composition of the composition is based on the quality of the ten progress 3 from Ta: 0.001 〇 / 〇 and 0.010% or less, Sn: at least 5% or more of the elements selected from the above (4). 2% or less. Shen. (4) New_zinc steel sheet having excellent workability and impact resistance according to any one of items i to 5 of the monthly patent range, wherein the composition of the composition is Sb: 0·002% or more according to the quality/〇σ10 progress. 0.2% or less. 7. A method for producing a high-strength molten ore plate having excellent susceptibility and impact resistance, which is to be subjected to hot rolling of a steel slab having a composition of any one of claims 1 to 6 According to 3 〇〇 it is above and 57 〇. The hot-rolled sheet obtained by coiling at the following temperature is pickled or further cold-rolled, and then, in the temperature range of 750 to 900 ° C, the condition of the following formula is satisfied according to t: holding time (s) After annealing, 15^t^47.6xl〇*10/exp(.27016/(T+273)) T: annealing temperature (. After cooling, keep the temperature range of 450~550 °C for 1〇~2〇 〇s, followed by hot-dip galvanizing, or further in the temperature range of 500~60 °C, according to Tave: 100102078 30 201137130 average holding temperature (°C) and th: holding time (8) to meet the conditions of the following formula Alloying treatment of zinc; 0.45 ^ exp[200/(400-Tave)]xln(th)^ 1.0. 100102078 31 201137130 IV. Designation of representative drawings: (1) The representative representative of the case is: No (2) Representative figure Brief description of the component symbols: None. If there is a chemical formula in this case, please disclose the chemical formula that best shows the characteristics of the invention: None 100102078 2