TW583316B - High strength galvannealed steel sheet having an excellent formability and method for producing the same - Google Patents

Abstract

The present invention provides a high strength galvannealed steel sheet having excellent formability and a method for production of the same. The galvannealed steel sheet contains, in terms of wt %, C; 0.05-0.15%, Si: 0.3-2.0%, Mn: 1.0-2.8%, P: less than 0.03%, S: less than 0.02%, Al: 0.005-0.5%, and N: less than 0.0060%, satisfying formulas: (%Mn)/(%C) >= 15, and (%Si)/(%C) >= 4, and the balance being Fe and unavoidable impurities, with a galvanizing coating layer containing, in terms of wt %, Al: 0.05-0.5%, Fe: 5-15%, and the balance being Zn and unavoidable impurities. The galvannealed steel sheet satisfies a relationship of L >= 52-0.035xF, wherein F: tensile strength (MPa) and L: elongation (%).

Description

[Technical Field of the Invention] The present invention relates to a high-strength alloyed molten zinc electroplated steel sheet and a method for manufacturing the same. More specifically, the present invention relates to an excellent processability and can be applied to, for example, a building material or an automobile. Electroplated steel sheet for various purposes such as steel sheet. Γ Previous technology ^ a Jinhua k fused zinc electric ore steel plate is a good electric money steel plate. The alloyed molten zinc electroplated steel sheet is usually manufactured by the following steps: After the steel sheet is removed from the moon, it is preheated in an oxidation-free furnace, and then reduced and annealed in a reduction furnace to achieve surface quietness and material assurance, followed by dipping It is crushed in a molten zinc bath and alloyed after controlling the amount of adhesion. Because it is characterized by excellent corrosion resistance and electroplating adhesion, it is widely used, especially for automotive and building material applications. Especially in recent years, in the automobile field, in order to balance both the function of protecting passengers during a collision and the weight reduction for the purpose of improving fuel economy, it is necessary to increase the strength of the plated steel sheet. In order to increase the strength of the steel sheet without deteriorating the workability, it is effective to add elements such as Si, Mn, or p. However, the addition of these elements delays the alloying, and therefore requires higher temperature and longer time than mild steel. Of alloying. The alloying at high temperature for a long time will transform the remaining Wastfield iron in the steel sheet into a Polite cast iron and cause a reduction in the guarding property. As a result, the effect of adding the elements will be offset.合金 The alloying of Si-added high-strength steel sheets' Japanese Unexamined Patent Publication No. 9 discloses a manufacturing method that can be realized by a continuous electric melting operation line, but the range of the manufacturing conditions is described in 583316. 发明, Description of the invention It is very extensive and lacks practicality in actual production. In addition, the manufacturing method disclosed in JP-A-U · η · said that the method is to maintain a low temperature after power ore to generate a residual Vossfield iron. However, this method causes an increase in equipment and deteriorates productivity. 5 [Akichi ^] Therefore, the object of the present invention is to solve the above-mentioned problems, to provide a high-strength alloyed molten zinc electric ore steel plate with excellent processability, and no need to install new equipment.

That is, a method for manufacturing a high-strength alloyed molten zinc electric-bonded steel sheet having excellent workability. 10 The results of the intensive research on the plating treatment of high-strength steel plates by the inventors have found that by using continuous molten zinc electroplating equipment that has the most suitable heat treatment conditions and plating conditions, a certain amount of C, Si, Mn or more is added. The steel is electroplated to produce a high-strength alloyed molten zinc electroplated steel sheet with excellent processability. 15 Also, the gist of the present invention is as described below.

(1) A high-strength alloyed molten zinc electroplated steel sheet with excellent processability, in terms of mass%, containing: C: 0.05 to 0.15%

Si: 0.3 ~ 2.0% 20 Μη: 1.0 ~ 2.8% P: 0.03% or less S: 0.02% or less A1: 0.005 ~ 0.5% Ν: 0.0060% or less, 7 583316 玖, the description of the invention and the remaining part is made of Fe and unavoidable Impurities are formed and (% Mn) / (% C) -12 and (% si) / (% c) -4 are satisfied when the content of C, Si, and Mn is% C,% Si, and% Mn, respectively. The surface of the high-strength steel sheet 'contains A1: 0.05 to 0.5% by mass, . : 5 to 15% by mass, 5 in a steel sheet having an alloyed molten zinc plating layer formed of Zn and unavoidable impurities, the relationship between tensile strength F (MPa) and elongation L (%) satisfies L-52- 0.035x F. (2) — A method for manufacturing a high-strength alloyed molten zinc electroplated steel sheet with excellent processability, which uses 10 as the steel billet composed of the chemical components described in (0), and completes the roll at a temperature above A1 · 3 After rolling, 50 to 85% of cold rolling is applied, and annealing is performed in a continuous molten zinc electroplating equipment at a temperature range of coexistence of ferrous iron and Vostian iron at 700 ° c to 8501, and then reaches from the southmost The temperature reaches an average cooling rate of 0.5 to 10 at 650 ° C. [: / Sec cools it, and then an average cooling rate of 3 to 650 ° C to 500 ° C (3: (/ sec)) After cooling and holding for 30 seconds to 240 seconds from 500 ° C to the plating bath, a molten zinc plating process is performed to form a molten zinc plating layer on the surface of the cold-rolled steel sheet, and then the molten zinc electrode is formed. The alloyed molten zinc electroplated steel sheet of the steel sheet M1 described above is subjected to an alloying treatment to form an alloyed molten zinc electroplated layer on the surface of the aforementioned steel sheet. Its 20 characteristics are: effective A1 concentration in the bath: 0.07 ~ 0.105 wt%, and the remaining part is made of Zn and unavoidable The molten zinc electroplating treatment is performed in a molten zinc electroplating bath composed of impurities formed by impurities, and the aforementioned alloying treatment satisfies 8 583316 玖, invention description 225 + 2500X [Α1%] $ τ $ 295 + 25〇χ [ A1%], but '[Al%]: Performed at a temperature T (° C) of the effective A1 concentration (mass%) in the bath in the zinc plating bath. (3) The excellent processability as described in (2) Manufacturing method of high-strength alloyed 5 smelting zinc electric ore steel plate, effective in the bath ^ Concentration meets: [A1%] S 0.103-0.008x [Si%] But '[Si%]: Si content in steel plate 〔quality%〕

The bath was performed at an effective A1 concentration (% by mass). (4) The method for manufacturing a high-strength alloyed molten zinc electroplated steel sheet with excellent workability of 10 as described in any one of (2) to (3), which is cooled to 400 ° C after the electricity is melted The time at the following temperature is 10 seconds or more and 100 seconds or less. (5) The method for manufacturing a high-strength alloyed molten zinc electroplated steel sheet having excellent processability as described in any one of (2) to (4), wherein the temperature of the molten zinc 15 plating bath is less than 460 ° C.

(6) The method for manufacturing a high-strength alloyed molten zinc electric shovel steel plate with excellent workability as described in any one of (2) to (5), which is cooled to 450 ° C or lower after annealing and then heated. At a temperature exceeding 45 × χ :, a molten zinc plating process is performed. [Embodiment] Embodiments of the invention The present invention will be described in detail below. Numerical limit

First, the reasons for C, Si, Mn, p, §, Al, and N will be described. 9 583316 发明. Description of the invention c. It is an element necessary to increase the strength of the steel sheet by attempting to strengthen the structure by using Asada loose iron or residual Vostian iron. The reason why the content of c is more than 0.005% is that if C is less than 0 · () 5%, on a molten zinc electroplating operation line that is difficult to rapidly cool from the annealing temperature by using spray or jet water as a refrigerant, Xueming 5 carbon iron Or Polite cast iron is easy, so it is difficult to ensure the required tensile strength. On the other hand, the reason why the content of C is less than 0.15% is that if C exceeds 0.15 / 〇, it is difficult to form a sound welded part by spot welding. At the same time, the segregation of C becomes significant, and the processability will be significant. Degradation.

Si is added as an element that increases the strength without significantly impairing the workability of the steel sheet, especially when the elongation is 10, so that the mass of 0/0 is 4 times or more of the C content. The reason why the Si content is more than 0.3% is that if Si is less than 0.3%, it is difficult to ensure the required tensile strength, and the reason that the & content is less than 0.2% is that if Si exceeds 20%, it increases. The effect of strength is saturated and at the same time it causes a reduction in ductility. In addition, by setting the mass% 15 to 4 times or more the C content, it is possible to significantly delay the transformation of Polite cast iron and deformed body during reheating for alloying treatment immediately after electroplating. In addition, the metal structure may be such that, after cooling to room temperature, there is a volume of 3 to 20% of Asada loose iron and residual Vostian iron mixed in the ferrous iron. Since Mn will reduce the free energy of Vosstian Iron together with c, it is added for the purpose of stabilizing Vosstian Iron during the period before the steel strip is immersed in the plating bath, and 1.0% is added. The above Mη. In addition, by adding 12% or more of its mass% to the C content, it is possible to significantly delay the transformation of Polite cast iron and deformed body during reheating for alloying treatment immediately after electroplating. The metal structure can also be: after cooling to room temperature, there is a body 10 583316 说明, the description of the invention is 3 to 20% of the volume of Asada loose iron and residual Vostian iron mixed in the fertile iron. However, if the added amount is too large, the flat steel billet tends to crack and the spot weldability is deteriorated. Therefore, the upper limit is 2.8%.

P is generally contained in steel with unavoidable impurities, but if its content exceeds 5%, it will not only significantly degrade the spot weldability, but also the high-strength steel plate whose tensile strength exceeds 490 MPa. Since cold rolling becomes significantly deteriorated, the content is made 0.03% or less. S is generally contained in steel with unavoidable impurities. If the amount exceeds 0.02%, the existence of MnS stretched in the rolling direction becomes significant, which will adversely affect the flexibility of the steel sheet. Therefore, The content should be 0.02% or less.

A1 is used as a deoxidizing element of steel, or used to suppress the fine graining of hot-rolled materials caused by A1N, and the coarsening of crystal grains in a series of heat treatment steps to improve the material, so it must be added more than 0.005%. However, if it exceeds 0.5%, the cost will increase and the surface properties will be deteriorated. Therefore, the amount will be less than 0.5%. N is generally contained in steel as unavoidable impurities, but if its amount exceeds 0.006%, the brittleness will be deteriorated together with elongation, so the content is made 0.006% or less. There is also a case where the steel containing these as the main components contains Nb, Ti, B, Mo, Cu, Sn 20, Zn, Zr, W, Cr, Ni even if the total content is 1% or less. , Co, Ca, (Y), V, Ta, Hf, Pb, Mg, As, Sb, Bi, will not impair the effect of the present invention, and can improve corrosion resistance or processability depending on the amount. Next, the alloyed molten zinc plating layer will be described. In the present invention, the A1 composition of the alloyed molten zinc electroplated layer is limited to 11 583316 玖, and the reason for the description of the invention is 0.05 to 0.5 夤 篁% because if it is less than 0.05% by mass, the Zn-Fe alloy is subjected to alloying treatment. The alloying will progress excessively, and the fragile alloy layer will be overdeveloped at the rubite interface, which will deteriorate the plating adhesion. If it exceeds 0.5% by mass, the Fe-Al_Zn barrier layer will be formed too thick, and the alloying treatment will be performed. Temporal alloying ... "Unable to progress" may result in the plating of the target content being unavailable. The reason why the Fe composition is limited to 5 to 15% by mass is that if it is less than 5% by mass, a soft Zn-Fe alloy is formed on the surface of the plating layer, which deteriorates the press formability, and if it exceeds 15% by mass, the alloy is weak. The layer will be overdeveloped at the interface of the red alumite spring and deteriorate the plating adhesion. 10 The steel sheet of the present invention may be contained or mixed in the k-melt electroless mineral bath or the electroless mineral bath. Pb, Sb, Si, Sn, Mg, Mn, Ni, Ci *, Co, Ca, Cu, Li, Ti, Be, Bi, and rare earth elements selected from i or two or more kinds will not impair the effect of the present invention, and may improve surname resistance or processability depending on the amount thereof. The adhesion amount 15 of the alloyed molten zinc plating is not particularly limited, but from the viewpoint of corrosion resistance, it is preferably 20 g / m2 or more, and from the viewpoint of economy, it is preferably 15 g / m2 or less. The high-strength alloyed molten zinc electroplated steel sheet with excellent workability of the present invention has a tensile strength TS above 490 MPa, and the relationship between the tensile strength F (MPa) * 20 and the elongation L (%) satisfies l $ 52-0.035x F. -· Elongation: The reason why L is limited to [52-0.035XF]% or more is that when L is lower than [52-0.035x F], breakage and other situations will occur during intense processing such as deep drawing. Sexual insufficiency. Next, the reasons for limiting the manufacturing conditions will be described. 12 583316 Mei, description of the invention The purpose of the manufacturing conditions is to make the metal structure into 3 ~ 20% of Ma Tian loose iron and residual Vostian iron. When I has ϋ exceeding to have both high strength and good pressability

The purpose of the present invention is achieved. The flat steel slab supplied to the hot rolling is not particularly limited, as long as it is produced by a continuous casting flat steel slab or a thin flat steel slab continuous casting machine. Also applicable: continuous casting of hot rolling immediately after casting ~ vertical rolling (~) 10 processes. The completion temperature of hot rolling must be at least the point from the viewpoint of ensuring the press formability of the steel sheet. There are no particular restrictions on the cooling conditions or coiling temperature after hot rolling, but in order to prevent the material quality at both ends of the coil from becoming larger and larger, or to avoid the deterioration of pickling properties due to the increase in size and thickness, it is set to 750 ° Below C is preferred, and if part of the deformed body or Asada loose iron is formed, lug rupture is likely to occur during cold rolling, and even extreme cases may even cause steel plate fracture. Therefore, it is preferably 55 (TC or higher. Cold) Rolling can be carried out under normal conditions, but based on the purpose of finely dispersing the Asada loose iron and the residual Vostian iron so that the ferrous iron can be easily processed and hardened, and the maximum workability is increased by 20 liters, so the pro-rolling rate is 50. On the other hand, if cold rolling is performed at a rolling rate exceeding 85%, an excessive cold rolling load is required, which is impractical. When annealing is performed by continuous molten zinc electroplating equipment using in-line annealing 'The annealing temperature is 70 ° C (fertile grain iron above 850 ° C and below, 沃 田 13 玖, invention description iron two-phase coexistence field. Annealing temperature G, person / dish degree less than 700 C, recrystallization is not enough full, Method to make the steel sheet have the required pressability. If annealing is performed at a degree of brewing exceeding 85 ° C., the growth of the oxide layer of Si or Mn on the surface of the steel strip will occur. It is suitable. In the process of subsequent submersion cooling to electricity M and 5 baths, even if the iron is not allowed to grow even with slow cooling to 65 ° C, a sufficient volume ratio, the cooling from 65 ° C to the plating bath On the way, Vostian Iron is transformed into Asada scattered iron. In the subsequent reheating of alloying treatment, Asada scattered iron will be tempered, which will cause precipitation of carbon iron. Therefore, it is difficult to have both high strength and good pressure processing. 10 After the steel strip is annealed, it is cooled during the subsequent immersion in the plating bath. At this time, the cooling rate is from the highest reaching temperature to 65 (rc to an average of 0.5 to 10 C / s, and then from 650 ° C to Cool it at 500 ° C at an average cooling rate of 3 ^ / s or more, and then hold it from 50 ° C to the plating bath for 30 seconds or more and 240 seconds or less, then immerse it in the electric money bath. 15 Set the cooling rate to 65 ( The purpose up to TC is 0.5 ~ 10 ° C / sec. The purpose is to increase iron content in order to improve workability. At the same time, by increasing the C concentration of Vostian Iron, the free energy generation is reduced, and the temperature at which the metamorphosis of the Asada iron begins is below the temperature of the plating bath. If the average cooling rate up to 650 ° C is less than 0 .5 ° C / s, it is necessary to lengthen the length of the continuous melting zinc power ore 20 equipment operation line, which leads to increased costs, so that the average cooling rate up to 650 ° C ·· 0.5 it / s. The average cooling rate up to 650 ° C is less than 0.5t / s. It is conceivable to reduce the maximum reaching temperature and anneal at a temperature where the volume ratio of Vostian iron is small. However, in this case, it can be used in actual operation. Allowable 14 玖, the description of the invention / the degree of fe range is relatively narrow compared to the 'appropriate temperature range, as long as the annealing temperature is slightly reduced, the Vostian iron cannot be formed, and the purpose cannot be achieved. On the other hand, if the average cooling rate up to 65 ° C exceeds 10 °. 〇 / s, not only does the volume ratio of ferrous iron increase insufficiently, but also the increase of c · / agronomy in Vostian iron is very small '. Therefore, before the steel strip was immersed in the electric ore bath, it was partially deformed into Asada powder. Iron, and thereafter, as a result of tempering during the heating for alloying treatment, the loose Asada iron is precipitated as cis-iron carbon iron, so it is difficult to have both high strength and good pressability. · Make the average cooling rate from 650t to 5G (rC) be 3 seconds or more. 10 is to prevent Vostian iron from transforming into Polite iron during cooling. If the cooling rate is less than 3 ° c / s, Then, even if it is annealed at the temperature specified in the present invention and cooled to 650 ... ', the generation of Polite cast iron cannot be avoided. The upper limit of the average cold section speed is not particularly specified, but the average cooling speed must be exceeded in a dry environment. It is difficult to cool the steel strip at 2CTC / sec. 15 The reason to keep it for 30 seconds or more and 240 seconds or less from 5000 C to the electric ore bath is because if it is less than 30 seconds, the shell 11 C will be concentrated toward the Vostian Iron. Become # is not enough, resulting in the concentration of c in Vosstian iron cannot make the residue of Vosstian iron at room temperature reach a possible level. If it exceeds ·, then the transformation of Lexus body will be excessive and cause the amount of Vostian iron to decrease. , And unable to generate a sufficient amount of ", 20 Remaining Vosstian Iron. Moreover, the retention period from the 50 (TC_ electric boat bath ^, once cooled to below 450 ° C and held for more than 25 seconds, can promote C toward Voss Concentration in Tiantie, resulting in high processability The degree of alloying dazzles the electric key. However, because the steel plate is immersed in the plating bath below 45 ° C, it will cool the plating bath 15 583316 玖, but the description of the invention solidifies, so it must be reheated to more than 450 ° C. After the temperature, the molten zinc electroplating treatment is performed. In the production of the alloyed molten zinc electroplated steel sheet of the present invention, the smelting zinc electro-ore bath used is A1 concentration, and the effective A1 concentration C in the bath is adjusted to 50.07 ~ 〇 · 105% by mass. Here, the effective A1 concentration in the plating bath refers to a value obtained by subtracting the Fe concentration in the bath from the A1 concentration in the bath. The effective A1 concentration in the bath is limited to 0.07 ~ 〇 · ι〇 The reason for 5% by mass is that if the effective concentration is less than 0.07%, the formation of the Fe-Al-Zn phase that becomes an alloyed barrier at the beginning of electroplating is insufficient, resulting in a fragile 10 Γ phase during electroplating. The interface of the steel sheet is thickened, so that only alloyed molten zinc electroplated steel sheet with degraded electric film strength during processing can be obtained. On the other hand, if the effective A1 concentration is higher than 0.15%, it requires high temperature and long time alloying. 'Wastfield iron remaining in steel will transform into waves Special cast steel can not balance high strength with excellent workability. 15 In addition, the alloying temperature during alloying in the present invention satisfies: 225 + 2500x [Al%] gT $ 295 + 2500x [Α1%] However, [A1%]: performed at a temperature T (° C) of the effective A1 concentration (mass 0 / 〇) in the bath in the zinc plating bath. The alloying temperature T is limited to [225 + 2500x [Al%]] ° Above c, 20 [295 + 2500X [A1%]] The reason below it is because if the alloying temperature τ is lower than [225 + 2500χ [Al%]] t: it will make alloying impossible or impossible. Sufficient and unalloyed, the plating surface is covered with the Γ phase or 7 / phase which is degraded in processability. In addition, if τ is higher than [295 + 2500X [Al%]] ° C, the alloying progresses excessively, exceeding the Fe% of the plating of the invention 16 583316 玖, the invention description, which will increase the decrease of the adhesion of the plating during processing. . In the present invention, if the alloying temperature is too high, the remaining Vostian iron in the steel will be transformed into Polite cast iron, and the intended steel plate having both high strength and processing properties cannot be obtained. Therefore, once the amount of Si added becomes difficult to alloy, it is effective to reduce the effective Al concentration in the bath to lower the alloying temperature in order to improve the processability. Specifically, electroplating is performed in a bath that satisfies: [Al%] g0.01-3.000.08 [Si%] # But '[Si%]: Si content in the steel sheet [mass%] 10 bath Medium effective Al concentration (% by mass) was performed. The effective A1 > degree is limited to [〇. 1 〇3-〇 · 〇〇χ (§ 丨%]] The reason below is' if the effective A1% concentration is higher than [〇 · ι〇3-〇 · 〇〇χ [Si%]], it requires alloying at a high temperature for a long time, which leads to the transformation of the residual Vostian iron in the steel into a Pollit cast steel, which deteriorates the workability. 15 The reason why the time for cooling to 400 ° C or lower after hot-dip plating is limited to 1Q seconds to 100 seconds is that if the temperature is less than 10 seconds, the concentration of c will be insufficient toward Vostian Iron. The C concentration in Vosstian iron cannot make the residue of Vosstian iron at room temperature reach the possible level. If it exceeds 100 seconds, the deformed body will be excessively excessive, resulting in a decrease in the amount of Vossirta iron and it will not produce 20%. Sufficient amount of residual Vostian iron. It is preferably from 10 seconds to 80 seconds. In the present invention, there is no particular limitation on the heating method of the alloying furnace, as long as the temperature of the present invention can be ensured, radiant heating or south frequency induction heating using a general gas furnace can be used. In addition, the method of cooling from the highest reaching temperature after alloying is not limited. After alloying, if the heat is blocked by airtightness, etc., 17 583316 玖, description of the invention, it is sufficient to open it, or it can be used more quickly There is no problem in cooling gas cooling. The reason why the temperature of the molten zinc electroplating bath is limited to less than 4601 is because the right is above 460 C, and the formation of the Fe-Al-5 Zl1 phase, which becomes the alloying barrier in the early stage of plating, progresses excessively, causing the alloying temperature to rise, especially in Si Adding a steel grade to the bottom can easily cause a decrease in workability. The lower limit of the bath temperature is not particularly limited, but since the melting point of zinc is 4ΐ9 · 47π,

On the other hand, a bath temperature above this temperature can be used for melt plating. Example 10 Hereinafter, the present invention will be specifically described by way of examples. (Example 1) The flat steel slab formed by the composition not shown in Table 1 was heated to a temperature of 910 ~ 93 (rc) to form a 45mm hot-rolled steel strip and wound under a lion ~ 6 thief. After pickling After applying cold rolling to make 6mm cold rolled 15 steel strip, using continuous melting and electric forging equipment with annealing in the operation line,

The heat treatment and electric forging were performed under the conditions shown in Table 2 to produce an alloyed molten zinc electroplated steel sheet. 20 JIS No. 5 test piece was cut from each steel plate and tested to determine the tensile strength (TS) and elongation (don't pass the tensile strength at room temperature to 49.0 MPa or higher, and the elongation was qualified to [52_0 · 035χ. The adhesion amount of the plating film, Fe, VIII concentration, and tensile strength]% are determined by dissolving the film with hydrochloric acid with an inhibitor, and passing the ICp 5 to 15% to qualify. Measurement. The Fe concentration in the plating is evaluated The results are shown in Table 2. The C content in the 遽 1 steel is outside the range of 18 5 10 15 、, the description of the invention, so the tensile strength is not in the number 2. The Si content in the 2 steel is outside the scope of the invention. Therefore, the tensile strength and elongation are unqualified. The content of p in the steel of No. 3 series is outside the scope of the present invention, so the elongation is unqualified. Outside the range, the elongation is unqualified. The Mn content in the axis 9 is outside the range of the present invention, so the tensile strength and elongation are unqualified. The alloying temperatures of the No. 12, 29 series are outside the range of the present invention, so the elongation is unqualified. Failure. The number M is the alloying temperature within the scope of the present invention. In addition, the Fe% in the electricity bill is unqualified. Numbers 20 and 30 are from the highest reaching temperature to ㈣. The average cooling rate up to c is outside the scope of the present invention, so elongation is unqualified. Number 21 is from loading to electroplating The holding time until the Luo is outside the scope of the present invention, so the elongation is unqualified. The application content / c content in the steel of the 26 series is outside the scope of the present invention, so the elongation is unqualified. The Si content in the steel of the 27 series The / c content is outside the range of the present invention, so the elongation is unacceptable. The number 31 is an average cooling temperature from 65 ° to 500. The average cooling temperature so far is outside the range of the present invention, so the elongation is unacceptable. The content of Mn in steel No. 32 is outside the scope of the present invention, so the elongation is unqualified. The content of c in steel No. 33 is outside the scope of the present invention, so the elongation is unqualified. It is an alloyed molten zinc electroplated steel sheet with high strength and good workability.

In addition, when the temperature of the plating bath is less than 460 ° C, it is possible to produce an alloyed molten zinc electroplated steel sheet having high strength and good workability regardless of the si content in the steel. On the other hand, if it is a low Si content of No. 5 or a low Si content of No. 35 and a low Fe%, it can be manufactured at 470 ° C. However, if the high Si content of No. 36 is increased, Fe%, it is necessary to increase the alloying temperature of 19 583316, and the invention shows that the temperature will cause elongation failure. Φ mm £ Φ • Λ3 ο% ΙΟ φ CO r- csl uri < ό ir ^ 〇i 〇i 5 try to Φ o CM CD < 0 < ri CO t \ im in CO C \ J mm 04 « Μ m 〇i ο Έ marriage ΙΟ CO CD t— * in CM CD o tn tQ CNl CM r- oi CM cn CM in oi < M CM eg UT5 CM CD CM CP wmm d CM 0) CSI to csi ζ: ri 04 Ο Ο 8 O CM sp CO CM 〇〇o 1 o < 〇CM ooo 8 8 O CM i O iD CO 〇o ro 〇〇 · o CM 〇oo ¢ 0 1: 〇〇o iO s 〇CD n 8 O 〇8 O «Ν aoo ζ W Goods CO ooosd LD e〇〇〇〇〇 > CM oo r > CM 〇CO Q o Bu 8 O: _ 1 od CD so < 0 CM O _ Concession: 丨Sense: d € D CM A 〇 plane moo < 0 oo CM d ω 8 ο m- er o CM 〇od CM 〇od goods o 〇o r > s 〇CM 8 O so © i 8 CM d arm s ci : Fiber sos 〇 < Μ a O 丨: meaning. Ooo double ooo in 〇od O o QL mi ._ m ο ooo ca n 〇o; m < mod σ > 雠 m Q m: e-; 〇o _ 8 O r ^ O odms 〇σ > odc〇δ d QO «0 § do HMNK Q om P Yeast 1 < 0 so C] BU CO i £ > BU T- * Cv» csi eo s in 〇 > di 〇. «IPM *. Mo« Ν in a > g CM «si S mmm csj r- C4 C4 o cr > 04 cJ ID« * 5 evi CO rnmm ω CO 〇 a% # * «» <: o * 05 Γ5 d CO d inch < 0 d CD CD o fNMK dz wmm in < D 〇 > i〇d 〇in O < £ > e > d CM CD 〇〇d inch 0 cq VMM m s 〇 〇 O < 3 > so ododr * · 〇dr ^ 〇〇r ^ 〇o δ § € 0 odoo d 5 inch oo CD, MM_ 〇moom O d nJ: Zhong < φ ϋ D UJ U. 0 X MMmh '' 2 Z 0 a 0 5 20 583316 Rose, invention description si

MliE # i4 1 In anger 1 ^ i4i ^ d 51/5 s ιοε < 00 «s i bu o eot 0 redundant Ijie 莩 佥 l-4ut one 4 anchor 1 ^ visit P9 s se 9 £ [¥ 轵 佥1-4 9 € 00 £ strs s < £ »ε I 衣 丘 炝 14 s < οε s 【# 承 念 141 | 笤 wi s ro s so s § s 8 s

SI s s 8 < 9 »2 s s s s s $ .i si 92 rs ru

SI

I S6 s s

TFT sv s s 5 s 3 ro s ro s s eo Γ0 2 3 εο 3 3 2 s s εο s s εο »2 丨 F ° i s s εο ro 2 2 3 εο 3 3 s s ¥ # coe sc sc se £ se s se

9CSI s s * € έΙ 2 οε s β

Ll ¾ ττ a 22 s a a

IF

R ilo ^^ 5 § e »? § § sw > i

B

9S §

OS csls

Iss δ β m § ii (o < ou i its i

Lp

QU δ S9 co2 «

Qs ss i i i

ie «D u > £ s £ (4.Γ- lf:; 3M < .- F% ': > os' s 09 s s s 8 s s 09 s s s

Ml

Is 09 s

Is o§ g s is

Is

Is

Itol 09 s ig 09 jltp 09

S

S m m 3%

I purple κ s φ zero t s g m s Φ

E 2

S m § m s g g? S 8 8

S

S s υη 〇? S g s ¥ i

I i g ¥ i § g

S ur > s i i s s s i?

I 8

O

I —ο • ^ 55 ^ · ϋ? Δ ϋ? 5 iinSOD • ΙΜ1 1S1 备 iigf liS? Ii5 ¥? 5 ^ rMU9— ϋδ ¥ ^ ¾. 10 1S5F ϋδΤ slgllol iiSF 1i5F 1S5F 1i5 ¥ " 1I5F 5i5F sooRM sgi .. ^ _NMMMMioif— u • NMMMM loir ............. 3 ......., s ...... 111 —.,. 丨 ...................................... οε ...... .......................... la ....... .......................... 00 ............. ............ i oe ..................., g ..... ...............: 丨 .. 丨, 0 「『 丨 —-............. .◊ 丨 .. ^ 1 ...., ........ 1: .-. J..``. = ._ dian ... ........., 丨 丨, OSH ............. ............, 1S1 ............................. ............ S 0¾ ............. I la. 「： -1 ..: 6ε ...... srl: i 1S1 ..... ................ sc ....... ............ oc · gli g ......... I oe:, ... ...................................1. ............. ............................................................................. ....... Igl G ...— 1 丨 1.1 ^ .................... Di ........ M—ri ^丨 ...,: ... Iis, oos (± ϋ >? ^ U;? It 'u — 2] 2 urv >2; —

HE

JfTMl 3 §0¾og OS ap group 0 =: =. 1 .. "-= QLl .................... ............................ Iglrl ..... ............ Iglr — OM Iglz ou β ............ .............. 08 i -i 1 Qs: one 丨 丨, ί i :: — 丨 1 丨 i β OS i loilgi as ioliu ......... i I i _ .. ::::: Isla .......... ....... Love ............... lili ............. gi ola .............. Sound Iglrl 丨 1 丨, .glI 丨! 1 ^! (P) ^ S5 ^ Snow ad—d!

D ili: HHN 0 bNwNNNi? Ro Jia 1 ^ 11¾.di " IFid— IN, d—d— JMidr l ^ ld—did—d—ra—d—d— §idtd—dld——9— 21 583316 玖Description of the invention * (Example 2) 'The flat steel slab formed by the composition shown in Table U was heated to a temperature of 0 t, and a hot milk steel strip of 4.5_ was made at a completion temperature of 9 breasts, at' 580 to 680 T : Take down. After pickling, apply cold rolling to make 16_ cold <. 5 steel strips, use continuous melting and electrowinning equipment of annealing method in the operation line, perform heat treatment and electric mining under the conditions shown in Table 3, manufacture Alloyed molten steel electroplated steel sheet. A JIS No. 5 test piece was cut from each steel plate, and the tensile strength (TS) and elongation (E1) were determined by performing a tensile test at room temperature. Tensile strength is acceptable if it is 49.0 MPa or more, and elongation is acceptable if it is [52 g () 35x tensile strength] H)%. The adhesion amount of the plating film and the Fe and A1 concentrations were determined by dissolving the film with hydrochloric acid containing an inhibitor and measuring #ICp. The concentration of ^ in power ore is 5 ~ 15%. The electrical adhesion is evaluated by the following method, that is, an adhesive tape (Selvan tape) is pasted on the compression side of the test piece in advance, and then the test piece is bent into a V shape by bending it at an angle of 60 at an angle of 60. After bending recovery, peel off the adhesive tape 'observe the peeling degree of the electric recording by visual inspection' and evaluate φ by the following classification, △ or more is acceptable. ◎: The peeling width of the electric ore layer is less than 1mm, 〇. The peeling width of the electric ore layer is more than 1mm and less than 6 mm, △: The peeling width of the electric ore layer is more than 6mm and less than 2mm, X: plating $, The peeling width of 20 is more than 12mm. The shellfish, fruit, and fruit are as shown in Table 3. Since the effective A1 concentration in the electric ore bath is outside the range of the present invention, the electric forging adhesion is unacceptable. No. 7 failed the extension because the effective A1 concentration in the electric money bath was outside the scope of the present invention. Since the effective concentration of No. 8 in the plating bath is outside the scope of the invention 22 583316 833 and the description of the invention, the Fe% in the plating is unacceptable. In addition, the products of the present invention are all alloyed molten zinc electroplated steel sheets with high strength and good workability.

23 583316 发明, Description of invention ί W 4

Jj $ Ο Ο < 1 Ο ο ο (1) W1

to CO

S κ ί $ S. 2 — CM o W _ in \ ά 5 £ ν C5 «Τ3 CNl r * >« * 5 Ο Λ ο ds ¥. Elephant sgs < ρ η * U · to s ΝΝ Γϊ砹 uum <

S g o g

SI 2 _ o

I ο ΙΟ < :) "

O s 8

S

I § ο ~ .f lvt? _ S d s ο ο τα uisrr * »-; o g

S

S g i / ai lx $ + τ Break: > xf

cf. ) Goods > > 二 K4- Tsoi'D ίο)

O < M COI s 8

S

I

I ο CM m s mrj $

X x

T

X

X

X

X

X s 583316 发明. Description of the invention As described above, the present invention is a person who can provide a high-strength alloyed molten zinc electroplated steel sheet having excellent workability and a method for manufacturing the same.

25

Claims (1)

583316 Patent application scope _ No. 91137504 patent application application patent scope amendment February 6, 1993 1. A high-strength alloyed molten zinc electroplated steel plate with excellent processability and tensile strength of 490MPa or more, based on quality In%, including: C: 0.05 ~ 0_15% 5 Si: 0.3 ~ 2.0% Μη: 1.0 ~ 2.8% P: 0.03% or less S: 0.02% or less A1: 0.005 to 0.5% 10 Ν: 0.0060% or less, and the remaining portion is formed of Fe and unavoidable impurities, and when% C,% Si, and% Mn are used as c When the content of Si, Si, Mn is high, the surface of a high-strength steel sheet that satisfies (% Μη) / (〇 / 〇C)-12 and (% si) / (, contains Ai: 0 05 ~ 0.5 mass%, Fe : 15 5 ~ 15 mass%, and the remainder is made of Zn and unavoidable impurities In the steel sheet of the alloyed molten zinc electroplated layer, the relationship between the tensile strength F (Μρ &) and the elongation L (%) satisfies 1-52-〇35xF. 2 · —A method for manufacturing a high-strength alloyed molten zinc electroplated steel plate with excellent processability and a tensile strength of 49 MPa or more, which is a flat steel composed of the chemical composition of the first period of the patent application 20 The blank is rolled at a temperature above the Ars point, and after cold rolling at 50 to 85%, it is subjected to continuous molten zinc electroplating equipment at 700. 〇 Above 85 (rc below the coexisting temperature range of ferrous grain iron and Vostian iron, and then from the last time to reach '65 degrees to an average cooling rate / 26 583316, pick up patent application seconds Cool it down, and then from 65 generations to 5 ° C. Cool it at an average cooling rate of 3 ° C / sec or more up to c, and hold it at 150 ° C for 30 seconds or more and 240 shifts or less until the key bath. Electric ore treatment, thereby forming a molten zinc electroplated layer on the surface of the cold-rolled steel sheet, and then performing an alloying treatment on the steel sheet on which the molten zinc electroplated layer is formed, thereby forming an alloyed melt on the surface of the steel sheet. The alloyed molten zinc electroplated steel sheet of the zinc electroplating layer is characterized by: effective A1 concentration in the bath: 0.07 to 0.05 wt% / 0, and the remaining part is composed of Zn and unavoidable impurities The aforementioned molten zinc plating treatment is performed in a composition of a molten zinc plating bath, and the aforementioned alloying treatment satisfies: 225 + 2500χ [A1%] $ T $ 295 + 2500χ [A1%], but, [A1%]: zinc Effective A1 concentration in the bath in the plating bath (Mass%) at a temperature T (° c). 3. The method for manufacturing a high-strength alloyed molten zinc electric ore steel plate with excellent processability and tensile strength of 490 MPa or more, as described in item 2 of the patent application, is based on The effective A1 concentration in the bath satisfies: [A1%] S0.i03-0.008x [Si%] However, [Si%]: si content in the steel sheet [mass%] Performed in the bath effective A1 concentration (mass%) . 4 · As in the patent application scope item 2 or 3, the manufacturing method of high-strength alloyed molten zinc electroplated steel sheet with excellent workability and tensile strength of 490 MPa or more is to cool it to 400 ° C after melt plating. The following temperature is 27 °, and the time between patent application days is τ from 10 seconds to 1 ο 0 seconds. 5. If the patent application scope of item 2 or 3 has excellent processability and tensile strength of 490MPa 卩 South strength The method of manufacturing alloyed molten steel electric ship steel plate is to make the temperature of the molten zinc electroplating bath less than 46 ° T: 5 6 · High strength alloy with excellent processability and tensile strength of 490MPa or more, such as the scope of patent application No. 4 Method for manufacturing molten zinc galvanized steel sheet ' It is to make the temperature of the molten zinc electric ore bath less than 46.0. 7. The high strength alloyed molten zinc electroplated steel plate with excellent processability and tensile strength of 490MPa or more, such as the item 2 or 3 of the patent application scope. The method is to cool to 450 ° C or lower after annealing, and then heat it to a temperature of more than 45 ° C to perform the zinc fusion bond treatment. 8. Excellent processability and tensile strength, as described in item 4 of the patent application. The method for manufacturing a high-strength alloyed molten zinc electroplated steel plate above 490MPa is cooled to 45 ° C after annealing, and then heated to a temperature exceeding 15 450 C to perform molten zinc electroplating. 9 · As stated in the patent scope, the manufacturing method of high-strength alloyed molten zinc electroplated steel sheet with excellent workability and tensile strength of 490 MPa or more is cooled to 450 after annealing. (; Hereafter, it is heated to a temperature exceeding 450 C to perform molten zinc electroplating treatment. 20 10 · High-strength alloyed molten zinc electroplating with excellent processability and tensile strength of 490 MPa or more as claimed in item 6 of the patent application range The manufacturing method of the steel plate is cooled to 45 ° C or lower after annealing, and then heated to a temperature exceeding 450 ° C to perform molten zinc electroplating. 28