TWI281518B - Hot-dip Zn-Al alloy-plated steel material with excellent bending workability and production method thereof - Google Patents

Abstract

A hot-dip Zn-Al alloy-plated steel material ensuring high corrosion resistance and excellent bending workability of the plating layer, and a production method thereof are provided, that is, a hot-dip Zn-Al alloy-plated steel material with excellent bending workability, having a plating layer comprising, in terms of mass%, from 25 to 85% of Al, from 0.05 to 5% of one or both of Cr and Mn, and Si in an amount of 0.5 to 10% of the Al content, with the balance being Zn and unavoidable impurities, wherein the average spangle size on the plating surface is 0.5 mm or more; and a production method thereof.

Description

1281518 IX. Description of the invention: [Technical field to which the invention pertains] Field of the invention 5

The present invention relates to a molten steel material which is used in building materials, automobiles, and home appliances. In particular, the present invention relates to a molten Zn-Al alloy electric ore steel which has high resistance to recording, which is mainly required for use in the field of building materials, and which is excellent in bending workability of a battery layer, and a method for producing the same. [Prior Art] Background of the Invention In the past, a method of applying electroplating Zn to the surface of a steel material to improve the resistance of the steel to the surname has been widely known, and even now, steel which has been subjected to electric forging is also produced and used by Dali. However, for a large number of applications, only Zn plating may cause insufficient corrosion resistance. Therefore, there is a molten Zn_Al alloy plated steel sheet (aluminum-plated 15 zinc-plated steel sheet) which is added to improve the corrosion resistance of the plating layer. For example, the melt disclosed in Japanese Laid-Open Patent Publication No. SHO 61-28748 is to apply 25 to 75 mass% of gossip, the A1 content of 〇.5% or more of si, and the remainder is essentially The alloy formed by 211 is plated to obtain good cockroach|insect. However, in recent years, it has been demanded to further improve the corrosion resistance in the field of building materials use. In response to this, the inventors have developed a Zn-Al plating which has been disclosed in Japanese Patent Laid-Open Publication No. 2002-356759. The alloy plating layer of Cr and Mg is added to the layer, and the high-corrosion-resistant Zn_A1_Cr alloy electroplated steel of the molten Zn_A1 alloy plated steel plate (galvanized steel plate) is passed over. However, the plated steel material is bent as it is or after the coating 1281518, and the plated layer is often cracked, which causes a problem of impairing the appearance of the bending process or the low surface resistance. The purpose of the present invention is to provide a Zn-mould, an alloy electric-axis material, and a method for producing the same, which can solve the above problems in the Zn_A1_Cr alloy electric clock steel, and have excellent bending workability of the high-resistance and electron-electrode layer. [Peak-Ming] The Summary of Invention 10 15 & ^The monthly investigation and manufacture of the electric layer structure and manufacture of the Ζη·Α1 series alloy electroplated steel, and the investigation of the bending processability of the second and the electroplated layer. According to the technique disclosed below, a molten Ζη_Α1 alloy plated steel material excellent in bending of a plating layer and a method for producing the same can be obtained. (1) A molten Ζη-Al-based alloy plated steel material having excellent bending workability has a plating layer containing one or two of A1: 25 to M% Cr and Mn by mass%: 〇·〇5~5% and Si: A1 content is 〇5~1〇<7 and the remaining part is composed of 211 and unavoidable impurities, and the material size of the material is The average value is 〇.5rnm or more. . (2) A molten Zn-Al alloy, which is excellent in bending workability according to the item (1), wherein the plating layer contains (^: 〇1% by mass in β%. Bay 1 (3) as the first (1) (b) (1) as in (1) The molten Ζη, Αι ^ gold plated steel material having excellent bending workability in the item or the item (2), wherein the interface between the plating layer and the steel material has eight 20 1281518, one or two alloying layers of Cr and Μη (5) A molten Ζη-Α1 alloy-plated steel material having excellent bending workability as in the item (1) or (2), wherein an average value of the pattern size of the plating surface is 1.0 mm or more. 5 (6) In the molten Zn-Al alloy electric ore steel material which is excellent in the bending workability of the item (5), the average value of the pattern size of the electric ore surface is 3.0 mm or more. (7) The molten Zn-Al excellent in bending workability A method for producing an alloy plated steel material, which is a method for producing a molten Zn-Al alloy plated steel material according to item (1) or (2), wherein the steel material is impregnated In terms of mass%, one or two of A1: 10 25 to 85%, Cr, and Μη: 0.05 to 5% and Si: A1 content of 0.5 to 10%, and the remainder is made of Zn and inevitably In the plating bath made of the impurities, the cooling rate of the plated steel material until the temperature at which the plating layer is solidified after the melt plating is 20° C./sec or less, and after the solidification, the temperature is maintained by the following conditions (1). , ie: 15 y^7.5xl09xt'45...(l) (here, t represents the holding temperature of the electroplated steel of 100~250°c, and y represents the holding time (hr)). (8) as in the seventh (7) The method for producing a molten Zn-Al alloy electroplated steel material having excellent bending workability, wherein the electroplating bath further contains Mg: 0.1 to 5 mass%, for example, bending processing according to item (7) or item (8) The method for producing a molten Zn-Al alloy electroplated steel material having excellent properties, wherein the cooling rate is 15° C./sec or less. Brief description of the drawing 1281518 The first drawing shows the heat insulating condition after plating and the bending force of the plating layer. Relationship σ C C Cold Circulation DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail. The molten Ζη-Al-based alloy electroplated steel material having excellent corrosion resistance is characterized in that the composition of the electric money layer contains one or two kinds of A1: 25 to 85% by mass, Cr, and the like: 〇〇5 to 5% by mass of ASi. : A1 contains 〇5,^ and the remaining part is Zn and unavoidable impurities, and further contains μ 〇·1 to 5% by mass. Here, the so-called steel plated steel plate, g-line steel, etc. material. And steel 15 20 pen plating composition, A ^ 25 ~ 85% by mass. The righteousness is not full, and the resistance to the surname is reduced. When the amount of _ square & more than 85f is cut off, the resistance to pureness is lowered, and X is necessary to keep the temperature of the alloy thermocouple at = ', resulting in a high manufacturing cost. In addition, one or two types which are not included in the total composition of the electric ore are 〇·05 to 5 mass%, one of Cr and Mn, or _ mass: when, the effect of improving the purity is insufficient, and the quality is more than 5 % Viewpoints such as the increase in the amount of dross generated by the A heart. It is preferable that the amount of μ on the excess of μ is excessive. It is better to kiss. 1 quality 乂上~5 奸贝$%, more preferably 〇·2~5 mass%. In the composition of the electric ore layer, Sl is added to the 含有ι containing medium: the shape is too rich ^ is too thick, can improve the surface of the steel and the electric ore layer, and contains more than the AI content of the dirty section, because of inhibition 8 1281518

Fe_A1 alloying: shape, falling 虞', so the upper limit of AU is _%. In the case of the surface 1 workability, it is preferable to use 5% of the A1 content as the upper limit. %~〇 Also, the average size of the structure of the electric ore layer is 0.5 or more. Here, the flower-like phase is carried out by the light of the Wei surface. The mitochondria is used as the solidified tissue, generally (6) ‘, the micromirror is observed at a magnification of 50 times, and the middle of the dendritic structure is measured.

10

distance. When the average size of the Γ is less than the G.5 position, the electric recording material will be smashed, and multiple (four) marks will be generated, and the bending will be read and lowered. The pattern of the characteristic of the material is not visually recognized by W, and the appearance is impaired.时 When a higher level of bending and securing is required, the average value of the pattern size is preferably 1.0 mm or more, more preferably 3. 〇 mm or more. : There is no particular limitation on the upper limit. However, it is better to use 1Q or less because the size of the pattern becomes red and the appearance is degraded. The reason why this pattern size affects the workability of the plating layer is! The stage ^ is clear' but it is believed to be: ί 融 电镀 电镀 电镀 电镀 电镀 电镀 电镀 电 电 电 电 电 电 电 σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ σ The micronization and the hardness of the plating layer become high at the same time, so that when the bow is deformed, the crack of the plating layer is increased. Further, by the composition of the plating layer containing 〇1 to 5 mass% of \/^, a more excellent corrosion resistance can be obtained. When the addition is less than 0.1% by mass, the effect of adding the corrosion resistance to the edge is not observed. On the other hand, when the amount of addition exceeds 5 mass%, the effect of the insect resistance is saturated, and the possibility that the slag of the plating bath is generated is large. 1281518 "Afterwards, the structure of the electric ore layer is preferably formed in the alloying layer formed at the interface between the (10) layer and the bare steel, and the type or _ in the Mn is preferred. The thickening is in the Fe-A1 alloying layer. The ship and Mn are accompanied by the amount of the amount, and the electricity = the stage of exposing a part of the surface of the bare steel, by the pure action and the effect of the sacrifice (10), it is considered that the rot is inhibited by the naked steel. I play a role in insect growth.

The alloyed layer containing Cr and Mn can be confirmed by enthalpy analysis or GDS analysis of the cross section of the electrographic layer. The film thickness of the alloying layer is not particularly limited, but the effect of obtaining the roughness is reduced. On the other hand, since the bending workability of the electroplated layer is too large when it is too thick, it is preferably 3 μm or less. Further, the formation of the alloying layer is started after the electric ore steel is immersed in the smelting electric ore bath, and then the solidification of the electric ore layer is completed, and the temperature of the electric ore steel is about φ, and the bottom is the same. The thickness of the layer can be controlled by adjusting the temperature of the electric ore bath, the time of impregnation by the electric material, and the cooling rate of the electric job. In order to produce the back curve, the processing of the back is good, so the following must be further after solidification (保温) The conditions specified in the formula are: y^7.5xl〇9xr45...(i) (This is the holding temperature of the electroplated steel of 100~250°C, y is 20 times (hr)) In the first figure, the electroplating material is applied to a plating composition having a plating film thickness of 15 μm which is formed by a plating composition of 55% A1_15%Si·〇.2%CM%Mg-the remaining portion of Zn at a cooling rate of 15 seconds. Heating and heat treatment, investigating the relationship between the holding temperature and the holding time and the bending workability of the plating layer. Here, the bending workability test of the 10 1281518 plating layer is after the 3T bending process, and the uppermost length of the bending process is observed by a microscope. Lmm, based on the following criteria for judgment. (The so-called 3T bending plus It means that the board is bent by a dummy material with a thickness of 3 times the thickness (τ), and the 0Τ is the most rigid board, and is smoothly bent in the order of 1Τ, 21[, 3丁5.) ◎: no bending crack ( Compared with non-insulation heat treatment materials, it has a significant improvement effect) Ο : Bending "1~5 pieces (improved compared with non-insulation heat treatment materials) 10 15 △ • Bulging cracks 6~1G (with no insulation) When the heat treatment material is at the same level), when it is not full, c, in order to obtain the effect of improving the bending workability, it is necessary to keep the heat for a long period of time, which causes a problem of deterioration in productivity. Further, it is impossible to obtain further improvement effects when it exceeds 2 hours. The formula is obtained by obtaining a condition for improving the bending workability of the plating layer obtained in the experiment shown in Fig. 1, and multiplying the relationship between the heat retention temperature and the holding time to approximate the equation. # , ^ Again, The reason why the heat treatment of the coating layer can further improve the workability of the plating layer is presumed to be the following mechanism. In the state in which the electroplated material is produced, a large number of fine precipitated particles are present in the electric field. Fine granulation When the mother of the electric money layer writes and the shape of the song is obstructed, it will hinder the movement of the transfer, and the processing property of the electroplated layer will be degraded. The reader will heat the heat preservation treatment to make the fine precipitated particles coarse and coarse, and change the cover. The processing property of the layer is more than 25 〇. When the heat treatment of heat treatment is carried out, the coarse precipitated particles themselves are inside the electrolyte layer, and when the plating material is cooled, the fine precipitated particles are again produced. Processability of the plating layer is changed. ^ 20 1281518 In the composition of the plating layer, the remainder except A1, Cr, Mn, and Si are zinc and unavoidable impurities. Here, the unavoidable impurity means Pb. , Sb, Sn, Cd, Fe, Ni, Cu, Ή are equal to the inevitable mixing of the manufacturing process of the plating alloy raw material and are dissolved in the electric bell bath by the steel or the plating material during the electroplating reduction manufacturing process. The content of the elements of the unavoidable 2 is preferably 1% by mass or less in total. The coating film thickness is not particularly limited, but the durability of the key layer is too thin.

10 15

On the other hand, when the thickness is too thick, the bending workability of the electric ore layer is lowered, and problems such as cracks become easy to occur. Therefore, the film thickness is preferably 5 to 40/m. In particular, when good bending workability is necessary, the upper limit of the film thickness is preferably 15 mm or less. In the manufacturing method of the privately-plated steel material, the plated steel material is immersed in the plating, and the plating bath contains one of Al: 25-85%, Cr, Μη, in terms of asphyxiation λ ^ , 里 % Or 2 kinds: 〇〇5 讳人古λ, η °, Sl: Α1 contains 〇·5~10%, and it should contain Mg: 0·1~5 quality. ^ ^ m . The remaining part is composed of Zn and mussels which are not avoided, and A, ^ 1 _ 电镀 of the electroplated steel up to the k degree after the solidification of the electroplated layer is completed after the melting of the L ^ L ΓΛ . The speed of the 7-shirt is 2 CTC/sec or less, which is less than 15 C/sec, and more preferably less than 1/sec. In the case where the material to be plated is immersed in the galvanized coating, it may be subjected to an alkali dehydration treatment or a pickling treatment for the purpose of improving the electric money, the moisture resistance, the plating adhesion, and the like. The electric clock is galvanized steel loose, #八勺 method is used non-oxidizing furnace-reduction furnace or Wangzhuo original furnace will be electric money steel ^ ^ After heat reduction annealing, in the electroplating bath into the 仃 / fork > K starts. Receiver, preemptively with the method of gas removal (gas, Wiping)

The plating adhesion control is followed by the use of the 12 1281518 method in which the cooling step is continuously applied. Further, it is also applicable to a method of applying electroplating to a surface of an electroplated steel material by using a flux of zinc oxide, ammonium chloride or another chemical, and then immersing in an electroplating bath. In the method of preparing the plating bath, the alloy having the composition of the composition of the range 5 shown in the present invention may be heated and dissolved, or a combination of each metal monomer or two or more alloys may be used, followed by heating and dissolving to obtain a predetermined composition. As the heating and dissolving method, a method of directly dissolving a plating alloy in an electroplating bath may be used, or a method in which a plating alloy is previously dissolved in a preliminary dissolving furnace and then transferred to an electroplating bath may be used. Although the method of using the preliminary dissolution furnace is high in equipment installation cost, it is easy to remove impurities such as dross which are generated when the plating alloy is dissolved, and the temperature management of the plating bath is easy. In order to reduce the amount of oxide-based slag generated by the contact of the surface of the plating bath with the atmosphere, the surface of the plating bath may be covered with a heat-resistant material such as ceramic or glass wool. By cooling the solidification layer to the molten plating layer at a cooling rate of 15 2 (TC/sec, and solidifying after the solidification, the average value of the pattern size is 0.5 mm or more, and good processing is obtained. When the cooling rate exceeds 20 ° C / sec, not only the pattern size is refined, but also the bending workability of the plating layer is lowered, and the surface appearance is also impaired. When the condition of the above formula (1) is not maintained after solidification The pattern of the desired size of 20 is not obtained. The cooling rate control of the plated steel after melt plating is performed in the section where the electroplated steel is taken out from the molten plating bath to the completion of solidification of the plating layer. The specific method is to adjust the temperature of the atmosphere around the plated steel, Adjusting the relative wind speed towards the plated steel or adjusting it by heating in an induction heating or combustion furnace, 13 1281518. Furthermore, the cooling rate of the plated steel can be determined by measuring the plated steel from the molten plating bath to the molten plating. The time at which the solidification of the layer is completed is calculated. Here, the solidification of the molten plating layer can be completed by visually observing the change of the surface state. Further, the time to solidification can be obtained by dividing the distance at which the plating of the electric 5 is solidified by the manufacturing speed. The cooling rate of the electric ore steel after the solidification of the electric ore layer is not specified, but is 30°. In the present invention, in order to improve the bending workability of the plating layer, it is necessary to further heat the steel layer to a temperature of 10 (10) as specified in the above formula (1). The heat insulating method can be applied, for example, to continuous hot-melt plating, and the temperature of the plated steel material is cooled while maintaining the temperature of the plated steel material at a temperature higher than or equal to the temperature conditions specified in the present invention. When the temperature condition is lower than the temperature condition specified in the present invention, the method of heat-welding the steel plate by heating or heating the temperature of the temperature-receiving box or the steel plate is once taken up, and then heated to a predetermined temperature by an induction heating device or a continuous heating furnace, and then coiled and insulated. Further, the surface of the molten Zn-Al alloy electroplated steel of the present invention can be made of a polyester resin or an acrylic resin. , such as fluororesin, vinyl chloride resin, 20 urethane resin, epoxy resin, etc., roller coating, spray coating, curtain flow coating, impregnation coating, or laminating acrylic resin film In the case of forming a film on the plating layer, the flat portion, the cut end surface portion, and the curved portion can be excellent in a corrosive atmosphere, and the surname is excellent. 14 1281518 Hereinafter, The present invention will be described in more detail by way of examples. By immersing the electric ore steel in the molten electric ore metal tank of the composition of the table m, the conditions shown in Table 1 (the composition of the electric ore, and the solidification of the electric money layer are completed ^ The 5th temperature cooling rate, the solidification temperature after solidification, and the time) were processed to produce an alloy plated steel. Here, the present invention example N〇1, and comparison: Νο·2〇~22 is a sheet of 8 sides cold Rolled steel plate is tested for fat before electric money

The film was heated and reduced to 8 Torr in a 2-10% Η2 atmosphere. Thereafter, after cooling to 58 ° C, it was immersed in a molten metal ore bath for 2 seconds to form an electric ore layer on the surface. The plating film thickness is controlled by 10 to 15 alcohols. The molten electric ore bath temperature was 9 gamma in the present invention. c. This is the date of the day. _ Na c, the rest of the fine C. Thereafter, cooling and heat preservation were carried out under the conditions shown in Table 1. For the obtained electro-metal stripping of the electric money steel plate, the composition of the alloy layer of the electric ore portion and the bare steel interface of the electric ore was investigated by a chemical analysis method U. Electric mine

15 Attachment f = compare the weight before and after the electric record. Further, the size (average value) of the grain was observed by the optical microscopic surface. At the same time, the bending workability and the tamper resistance were evaluated by the following methods. (Bending workability test): & The last plated steel material was cut into a size of 3 〇 mm X 4 〇 mm, and the bowing force completion test of the electric ginseng layer was performed. The bending test of the plating layer was performed by the 3 mm bending addition, and the length of the uppermost part of the bending process of the 彳 彳 镜 , , , , , , , , , , , , , 。 。 。 。 。 。 。 。 。 。 。 。 。 ◎: no bending cracks ◦: bending cracks 1 to 5 15 1281518 △: bending cracks 6 to 10 X: bending cracks 10 or more (and only the money test) 20 days of alloy plating steel salt spray test. Electroplating 5 The method for measuring the amount of corrosion reduction was obtained by immersing the corrosion test material in a treatment bath of Cr 2200 g/L at a temperature of 80 ° C for 3 minutes to dissolve and remove the corrosion product. The mass measurement is accompanied by a reduction in the corrosion corrosion of the corrosion. Corrosion resistance was determined on the basis of the following evaluation criteria, and the above is acceptable. ◎: Electroplating corrosion reduction amount 5g/m2 or less 10 〇: Electroplating corrosion reduction amount 5g/m2 or more, 10g/m2 or less △: Electroplating corrosion reduction amount l〇g/m2 or more, 20g/m2 or less X: Electroplating rot I Amount of 20g/m2 or more 16 1281518

*考*4资浮苍u A 咐余性 0 0 Ο Ο Ο Ο Ο ο ®! 〇◎ ◎ ◎ ◎ 〇0 〇〇〇0 o <3 Bending workability △Ό 〇◎ 〇〇0 Ο 0 a 〇<] △~〇〇◎ ◎ ◎ ◎ ◎ XXX Insulation 1 time ο 4Tj <s oo O : to w-> O !: j ί L Temperature % ο S § Ο νη ο 110 130 160 150 100 160 150 260 240 240 190 190 150 1 1 1 ” a Cold! ^ ^ t ¥ 〇\ ο ^Ti ψ^· UV 2 On Ϊ—( 2 〇v cn tn 1—*丨uv vv ! »nom gl 〇寒4 壤5 ¥ ^ ΰο ο Λ ΪΛ Ο .3⁄4 '\Ti m β 5 β> 00 α> (Λ ό ί £ C0 «> m & C0 1 <Λ βΓ Kfi <Λ β> A (Λ <Λ 0> ρμ on ij Ο Uh xn <Λ αΓ (/} &0 <Λ 0> CO L3 <Λ o Uh 00 <lT Λ on oT fc c« <Λ 4> 江1 c/} Q> AC/J 1 <lT ίΛ ίί Fii pattern size imm^_ Ο Ο 1—ί Ο rn ο ο ο ^-4 ο ο Ο 9^ 1-H t—i 〇· Ο y^-io rW oor—* o ro 〇r—1 o O' CS d Cl o Si/Al ratio ___(Μλ____ 2.91 2.91 2,91 2.91 1 2.91 2.91 ί 2.91 J 1.00 2.50 2.91 2.91 2.91 ! 2.91 2.91 2.91 2.91 2.91 2.91 2.91 2.91 2.91 2.91 Μ N Remaining part of the rest Remaining part remaining part i 1 remaining part 1 1 remaining part I remaining part 1 remaining part 1 1 remaining part 1 I remaining part remaining part remaining part remaining part remaining part Remaining part of the remaining part of the remaining part Ί remaining part remaining份 q q — — — — q ;^. Ό· 'Ο r—< ο \〇\D v〇\D \〇\D v〇v〇·-t C 芝 S ! 1 1 ι 一 CSI ι 1 1 ! 1 II iji ! 1 1 U tn Ο d Vi Ο ο ο ! ν> ο Ο 〇Ί Ο d ό d *Λ dd d of d in O 〇i »〇d 〇i < «λ \η Vi ν% V"V Gg ΙΛ 40 ... *Λ in ir> ... ΜΊ in V"i 〇% rs inch Ο 00 ο O Ρ—* f·—· ra ro 寸 r—'. trj Ό 卜 00 Os r4 <N 17 1281518 As is clear from Table 1, all of Examples Nos. 1 to 19 of the present invention have good bending workability and money. On the other hand, in Comparative Examples Nos. 20 to 22, since the cooling rate after the electric ore was faster and the pattern size was small, the bending workability was poor. Further, in Comparative Examples Nos. 20 to 22, since the plating layer contained no Cr or Μη, it was insufficient for #5. INDUSTRIAL APPLICABILITY The molten Ζη-Al alloy electroplated steel material of the present invention has a good bending property of a plating layer, and therefore can be suitably used for building materials, automobiles, and home appliances that are often required for bending of steel materials. The industrial use price is extremely high. Further, in the method for producing an electroplated steel material according to the present invention, since the existing molten electroplating equipment can be used as it is, the manufacturing cost can be increased without being greatly increased, and the production can be easily and efficiently. Brief description of L mode 3 Fig. 1 shows the relationship between the insulation condition after plating and the bending process of the plating layer. [Main component symbol description] (none) 18

Claims (1)

128 ras 130121 Patent Application Patent Application Substitute Replacement 9βΤί 格:, 正 96. ί· -5 Patent Application Range: Life I This sound is added to 霣丨 1. A molten Ζη-Al alloy key with excellent bending workability The steel material has a plating layer containing, in mass%, one or two of A1: 25 to 85%, Cr, and Μη: 0.05 to 5% and Si: 0.5 to 10% of the A1 content. Further, the remaining portion is composed of Zn and unavoidable impurities, and the average value of the spangle size of the plating surface of the key steel material is 0.5 mm or more. 2. The molten Zn-Al alloy plated steel material excellent in bending workability according to the first aspect of the patent application, wherein the plating layer contains Cr: 0.1% by mass to 10% by mass to 5% by mass. 3. The molten Zn-Al alloy plated steel material excellent in bending workability according to the first or second aspect of the patent application, wherein the plating layer further contains Mg: 0.1 to 5% by mass. 4. The molten 15 Zn-Al alloy plated steel material having excellent bending workability according to the first or second aspect of the patent application, wherein the interface between the plating layer and the steel material has one or two alloys of Cr and Μη. Layer. 5. The molten Zn-Al alloy electroplated steel material having excellent bending workability according to the first or second aspect of the patent application, wherein the average size of the plating surface of the plating surface is 1.0 mm or more. 20. The molten Zn-Al alloy electric key steel material which is excellent in bending workability according to the fifth aspect of the patent application, wherein the average value of the pattern size of the electric key surface is 3.0 mm or more and 0. 7. The molten Zn excellent in bending workability - A method for producing an Al-based alloy electroplated steel material, which is a method for producing a molten Zn-Al-based alloy 19 1281518, f electroplated steel material according to claim 1 or 2, and which is obtained by impregnating a steel material with a mass% It contains one or two kinds of A1: 25 to 85%, Cr, and Μη: 0.05 to 5%, and 0.5 to 10% of the content of Si··Α1, and the remainder is made of Zn and inevitable. In the plating bath made of impurities, after the molten plating, the cooling rate of the plated steel material until the temperature at which the plating layer is solidified is 20 ° C / sec or less, and after solidification, the following formula (1) is used. The specified 'conditional insulation, ie: y^7.5xl09xf45...(l) (in this case, the temperature of the electric steel of the steel is not 10 0~2 5 0 C) y 10 is the holding time (hr) ). 8. The method for producing a molten Zn-Al alloy electroplated steel material which is excellent in bending workability according to the seventh aspect of the invention, wherein the plating bath further contains Mg: 0.1 to 5% by mass. A method of producing a Zn-Al-based alloy electroplated steel material which is excellent in bending workability according to the seventh or eighth aspect of the invention, wherein the cooling rate is 15 ° C /sec or less. 20