JPH08325697A - Hot-dip plated ferritic stainless steel sheet excellent in bending workability and its production - Google Patents

Abstract

PURPOSE: To produce a hot-dip plated ferritic stainless steel excellent in bending workability. CONSTITUTION: A hot-dip plated steel sheet in which an alloy layer present on the boundary between a ferritic stainless steel as a base material contg., by weight, <=0.08% C, <=1% Si, <=1% Mn, 11 to 25% Cr and <=0.03% N and furthermore contg. one or >= two kinds among <=1.5% Nb, <=0.5% Ti, <=2.5% Mo and <=0.5% Cu and a hot-dip plating layer is present by >=60% area ratio is subjected to one or, combinedly, >= two kinds among skinpass rolling of >=0.5% draft, bending type leveller straightening with a roll of <=100mm radius and tension type leveller straightening of >=0.2% elongation percentage, by which fine cracks are made present by >=90 lines/mm over the whole thickness of the alloy layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-dip ferritic stainless steel sheet and its manufacturing method, which are applied to building exterior materials, automobile members, etc., which are subject to bending and relatively light pressing.

[0002]

2. Description of the Related Art Ferrite-based stainless steel sheets that have been hot-dipped with Al or Zn are not only excellent in corrosion resistance and weather resistance but also have various appearances such as appearance, color tone and antiglare property. Since the surface can be provided relatively easily, the range of its application is expanding rapidly mainly in exterior building materials in recent years.

The surface of stainless steel is covered with a so-called passive film, and because of the surface oxide film formed by the heat treatment in the manufacturing process during hot dipping, the plating used in hot dipping is generally used. It is difficult to secure adhesion and avoid spot-like plating defects, and various ideas have been proposed to improve this point and manufacture sound hot-dip steel sheets.

[0004] For example, as means for improving the hot-dip plating adhesion of Cr-containing steel, JP-A-60-262950 and JP-A-61-147865 disclose electroplating of Ni in advance to form a hot-dip plated layer thereafter. Japanese Patent Application Laid-Open No. 64-28351 discloses a technique for pre-plating Fe—B alloy for the same purpose. Furthermore, JP-A-2-250948 and JP-A-3-250948
-28358, JP-A-3-28359, and JP-A-3-28359
36250, JP-A-3-56654, JP-A-3-6.
4437, JP-A-3-64438, and JP-A-3-6.
No. 4439 discloses a fragile alloy that facilitates reduction of surface oxides generated during heat treatment during the process during hot-dip plating of Cr-containing steel and forms between the plated metal and the base metal. A technique has been disclosed that attempts to improve plating adhesion during bending by reducing the layer thickness.

[0005]

However, even in the hot-dip ferritic stainless steel sheet having improved plating adhesion and workability as a hot-dipped steel sheet, when it is bent, the ferritic stainless steel of the substrate is used. There is a problem that brittle cracking occurs in which the steel sheet exhibits a cleavage fracture surface.

In particular, under recent circumstances where the atmospheric corrosion environment due to various exhaust gases, soot and the like is becoming severe, the base material itself of the hot dip plated steel sheet is expected to have better rust resistance and weather resistance. To increase the Cr content of the base material,
Higher alloys to which elements such as Mo and Nb have been added have come to be used, and the workability inevitably decreases by that amount. Therefore, such hot-dip ferritic stainless steel causes work cracking. It will be easy.

Further, in the roofing material, which is rapidly expanding its application as a material for hot-dip ferritic stainless steel sheet among building exterior materials, a longer member is advantageous in construction. The mainstream is roll forming, which is performed continuously in the longitudinal direction of the material, and the bending shape is relatively complicated and the local bending radius is often as severe as the plate thickness, and the processing speed is also relatively high. ,
Work cracking of hot dip ferritic stainless steel sheets is likely to occur.

Regarding such work cracking, for example, in the case of hot-dip Al-plated ferritic stainless steel sheet, a fragile alloy layer is formed at the boundary between the base material and the plating layer, but this alloy layer becomes thicker. It is known that if it is too much, cracks easily occur during processing to induce fracture of the plating layer. From this fact, Si having an action of suppressing excessive growth of the alloy layer is added to the Al bath at about 10 wt%. And Al
It is usual to stop the alloy layer containing -Fe-Si as a main component to have a thickness of about 3 [mu] m. However, since this alloy layer is extremely hard and brittle, cracking is inevitable when severe working is performed. On the other hand, if this alloy layer does not exist, there is a problem with the adhesion of the plated layer in the processed part, for example, even if there is no problem in the plating peeling test such as the so-called ball impact test performed in the state of a flat plate, the bending process Subsequent tape peeling tests, especially on the outer surface, allow easy peeling of the plating.

However, it has become clear that cracks that reach the base material stainless steel do not occur in such a material having poor plating adhesion after bending. That is,
Although the alloy layer in the hot-dip ferritic stainless steel sheet is useful for ensuring the plating adhesion of the worked part, it also has a harmful effect that it tends to become a starting point for inducing work cracking.

Further, according to the study by the present inventors, when a crack occurs even in the base material during bending of such a hot-dip ferritic stainless steel sheet, first, a brittle crack occurs in the alloy layer. Then, there is a starting point and it propagates into the plating layer and the base material stainless steel layer. At this time, it is clear that the cracks that particularly propagate to the base material side are brittle fracture surfaces at the initial stage. became. In addition, it is generally said that improvement of ductility is effective for improving bending workability, but in the case of hot dip ferritic stainless steel sheet, just improving the ductility of the base material causes the alloy layer to start as described above. It was found that it was difficult to suppress the progress of brittle fracture inside the substrate. That is, in order to improve the bendability of the hot-dip ferritic stainless steel sheet, it is necessary to make an improvement based on new knowledge, which is different from the ductility improvement measures based on the conventional knowledge.

In view of the above situation, the present invention provides a continuous bending process such as roll forming at a relatively high processing speed with a bending radius of about the plate thickness.
An object of the present invention is to provide a hot-dip ferritic stainless steel sheet which is free from work cracking and has excellent plating adhesion in a bent part.

[0012]

The present invention has been made on the basis of a new finding that is different from the conventional idea as described above. When a ferritic stainless steel plate is subjected to so-called hot dip plating such as Al or Zn. In the hard and brittle alloy layer formed at the boundary between the plating layer and the base material stainless steel plate, there are fine cracks at a certain frequency or more, and the stress generated by bending is generated in the alloy layer. Since the existing microcracks are released by opening, the propagation of brittle cracks inside the base material is inevitably avoided, and therefore, as a molten ferritic stainless steel sheet, in its alloy layer. Those that contain microcracks of a certain frequency or more are less likely to cause cracks in the base stainless steel even when subjected to severe bending, and not only can cracks in the plating layer be kept to a minimum Adhesiveness of the plating layer was found that having a good property of good, has been completed.

That is, according to the present invention, an alloy layer of the stainless steel and the hot dip plated metal is present at the interface between the surface of the ferritic stainless steel plated steel sheet and the hot dip plated layer, and cracks are present in the alloy layer. The gist is a hot-dip ferritic stainless steel sheet excellent in bending workability and a method for producing the same.

That is, specifically, the alloy layer of the stainless steel and the hot dip plated metal is present at an area ratio of at least 60% or more on the boundary surface between the ferritic stainless steel plated steel sheet and the hot dip plated layer, and the galvanized steel sheet is formed. A length 1 parallel to the surface of the steel sheet to be plated with fine cracks having a length of 50% or more of the thickness of the alloy layer when viewed from an arbitrary cross section perpendicular to the surface 1
It is a hot-dip ferritic stainless steel sheet having excellent bending workability, characterized in that it has 50 or more pieces per mm in the alloy layer, and further, at the interface between the ferritic stainless steel-plated steel sheet and the hot-dip layer, The area ratio of the alloy layer of stainless steel and hot dip metal is at least 60
% Or more, if necessary, after holding at a temperature of 350 to 400 ° C. for 5 hours or more, the maximum elongation rate of 0.1% or more is added to the alloy layer of the steel sheet to be plated and the hot dip plated metal, thereby plating. Presence of 50 or more fine cracks having a length of 50% or more of the alloy layer thickness in the alloy layer parallel to the surface of the steel sheet to be plated per 1 mm length viewed from an arbitrary cross section perpendicular to the steel sheet surface. Is a method for producing a hot dip ferritic stainless steel sheet having excellent bending workability.

In the above method, as a means for adding a maximum elongation of 0.1% or more, skin pass rolling, radius 100 mm
Either a bending type leveler straightening or a tension type leveler straightening that allows one or more of the following rolls to pass, or 2
More than one seed can be applied. Further, the above ferritic stainless steel sheet has a weight percentage of C: 0.08% or less,
Si: 1.0% or less, Mn: 1.0% or less,
Cr: 11 to 25%, N: 0.03% or less, and if necessary, Nb: 1.5% or less,
Ti: 0.5% or less, Mo: 2.5% or less,
Cu: Contains one or more of 0.5% or less,
The balance is Fe and unavoidable impurities. The hot-dip metal may be a metal containing Zn as a main component or a metal containing Al as a main component.

[0016]

Next, the present invention will be described in more detail.
First, in the hot-dip ferritic stainless steel according to the present invention, the alloy layer formed at the boundary between the hot-dip layer and the stainless steel plate to be plated needs to be present in an area ratio of 60% or more. . When the amount is less than this, the possibility that the plating layer is easily peeled off due to bending workability becomes extremely high. The presence or absence of the alloy layer can be sufficiently confirmed at a magnification of about 200 by a method for observing a metal cross-section structure with a usual optical microscope. The area ratio of the alloy layer referred to in the present invention is determined from the result of observing an arbitrary cross section perpendicular to the steel plate surface in a visual field of 200 times at least 20 visual fields, and a length parallel to the steel plate surface in the observing visual field. It is the ratio of the length where the alloy layer exists.

On the other hand, when the area ratio of the alloy layer is 60% or more, the adhesion of the plating layer is secured, but since the alloy layer is generally very fragile, when it is bent, Brittle cracks are generated and propagate inside the stainless steel plate to be plated or to the plating layer, causing cracks in the steel plate to be plated itself or cracks in the plating layer. In order to suppress this, it has been found that it is important to previously generate fine cracks in the alloy layer itself at a certain frequency or more. That is, as a result of various studies, when observing a cross section perpendicular to the surface of the plated steel sheet, 50 or more pieces are required per 1 mm in length parallel to the surface of the steel sheet. If the frequency is less than this, for example, when 90 ° bending is performed, the possibility that cracks will occur on the surface of the stainless steel plate to be plated becomes extremely high. Furthermore, in the case of 180 ° bending or severe processing with a high processing speed, it is preferable that the number of fine cracks be 90 or more per 1 mm in length.

The fine cracks in the alloy layer mentioned here have a length of 50% or more of the thickness of the alloy layer, as shown in the schematic view of FIG. It can be sufficiently confirmed by an observing method at about 200 times, and "50 lines per 1 mm in length" in the present invention is determined from the result of observing at least 20 fields in the field of view of 200 times. Even if the crack length in the alloy layer is 50 or more per 1 mm including cracks less than 50% of the alloy layer thickness, cracking may occur in the plated stainless steel sheet due to bending, so the crack length Is 50% or more of the alloy layer thickness.

Next, the reasons for limiting the components of the plated stainless steel will be described. C is an element that reduces the toughness of ferritic stainless steel, and in the case of the present invention, it is 0.08 wt.
% Is the upper limit. In hot-dip ferritic stainless steel sheets containing C in excess of this range, even if the frequency of microcracks in the alloy layer is 90 cracks / mm or more, the toughness of the base material is poor and cracking occurs during bending. Is likely to occur. The upper limit of N is 0.03wt for exactly the same reason as C.
%.

If Si is contained excessively, not only the workability in cold is significantly impaired, but also the toughness of the hot coil is deteriorated and the manufacturability of the base material itself is deteriorated.
% Or less. Mn is an element effective in suppressing the segregation of the deoxidizer and S to the grain boundaries, but excessive addition thereof lowers the ductility of the raw material, so Mn is made 1.0 wt% or less.

In stainless steel, Cr is a basic additive element essential for its corrosion resistance. From this meaning, the lower limit is 11 wt%. On the other hand, the corrosion resistance as stainless steel is improved depending on its content, but even if it is added in excess of 25%, its corrosion resistance improving effect is saturated and bending workability is significantly deteriorated. The upper limit is 25 wt%.

Nb is an additive element which is generally effective for ensuring the corrosion resistance of welds, especially the intergranular corrosion resistance, suppressing the coarsening of material crystal grains, and strengthening the material. Even for ferritic stainless steel, Nb is used for these purposes. Often added in. In the present invention, especially in order to improve the toughness in the hot coil stage from the viewpoint of ensuring the manufacturability of the base material ferritic stainless steel sheet, and from the viewpoint of ensuring workability and strength in the product plate, suppression of crystal grain coarsening For the purpose of, and further for ensuring the corrosion resistance of the welded portion, it can be selectively added. However, 1.5wt
If added in excess of%, not only these effects will be saturated, but also the toughness of the base stainless steel sheet will be significantly deteriorated, so 1.5 wt% was made the upper limit.

In the present invention, Ti can be selectively added for the same purpose as Nb. However, 0.5 wt%
Even if added in excess, the effects are saturated and the alloy cost is unnecessarily increased, so the upper limit was made 0.5 wt%.

Mo is an element effective for improving the corrosion resistance, and since it has a great effect of improving the resistance to local corrosion that cannot be obtained only by adding Cr, it is widely used in weather-resistant stainless steel. From the main purpose of using hot-dip ferritic stainless steel sheet as in the invention, Mo
Can also be selectively added. However, even if added in excess of 2.5 wt%, these effects saturate and unnecessarily increase the alloy cost, so 2.5 wt% was made the upper limit.

Cu can be selectively added in the present invention for the same purpose as Mo. However, 0.5 wt%
If added in excess of 0.5 wt%, not only will these effects be saturated, but the toughness of the base stainless steel plate will be significantly deteriorated, so 0.5 wt% was made the upper limit.

As described above, Nb, Ti, Mo and Cu can be selectively added in the present invention, but the hot dip ferritic stainless steel sheet of the present invention mainly has the weather resistance. At least 1 of these 4 elements is used because they are used and are often processed into complicated shapes.
It is preferable to include one or more kinds.

After the hot dipping treatment, the temperature is preferably kept at 350 to 400 ° C. for 5 hours or more. By heating and holding at 350 ° C or higher, the plating alloy layer softens,
Since the workability of the plated steel sheet is improved, the lower limit is set to 350
° C. However, if heated and held above 400 ° C,
Since the original stainless steel plate to be plated becomes brittle and conversely the bending workability is significantly impaired, 400 ° C. was set as the upper limit. In addition, when the heat retention time is less than 5 hours, the plating alloy layer is not sufficiently softened and the bending workability is not sufficiently improved, so the time was set to 5 hours or more.

Next, the reasons for limiting the means for making 50 cracks / mm or more of fine cracks exist in the alloy layer of the hot dip ferritic stainless steel sheet will be described. The maximum elongation to be added to the alloy layer of the steel sheet to be plated and the hot-dip metal is 0.
It was set to 1% or more. Here, the maximum elongation refers to the maximum value of the elongation deformation directly applied to either the front surface or the back surface of the alloy layer by skin pass rolling, leveler straightening, or the like. Since the alloy layer is hard and very brittle, it is easily crushed even with a small maximum elongation. 50 cracks / mm of fine cracks in the alloy layer due to the maximum elongation of 0.1% or more
Since it is possible to set the above, the lower limit of the maximum elongation added to the alloy layer is set to 0.1%.

Further, as described above, the alloy layer is harder than the steel sheet to be plated or the hot dip plated metal, and therefore skin pass rolling, radius 100 mm or less is used as a means for adding maximum elongation of 0.1% or more to the alloy layer. It is preferable to perform one or more of bending-type leveler straightening and tension-type leveler straightening, in which one or more rolls of (1) are passed.
Since the skin pass rolling is effective in finely dividing the plated alloy layer, it is desirable that the rolling reduction is 0.1% or more. However, if the rolling reduction is too large, work hardening occurs and conversely bending workability deteriorates. Therefore, it is desirable to set it to 3.0% or less. Leveler straightening is also effective for fine division of the plated alloy layer. When performing leveler straightening, there are two types, a bending type leveler and a tension type leveler. When performing bending type leveler straightening, if the roll radius is more than 100 mm, it is difficult to achieve a maximum elongation of 0.1% or more without sufficient bending deformation of the plating alloy layer, resulting in fine fragmentation of the plating alloy layer. Because it does not reach
The roll radius was 100 mm or less. Further, when performing tension type leveler straightening, if the elongation percentage is less than 0.1%, the maximum elongation percentage of 0.1% or more is not added to the alloy layer, and the fine division of the plated alloy layer does not occur. 0.1
% Is desirable.

[0030]

EXAMPLE A hot-rolled annealed 0.8 mm thick ferritic stainless steel having the chemical composition shown in Table 1 was used to produce a hot dip plated ferritic stainless steel sheet of Al or Zn. Then, this hot-dip ferritic stainless steel sheet was heat-treated, leveled, and skin-pass-rolled as shown in Table 2, bent at t / 2-90 ° and 180 °, and evaluated for cracks on the bent surface. The results are shown in Table 2.
Are also shown. In the observation and evaluation of the bent surface, in the Al-based plating, the plating metal layer was further dissolved with a concentrated aqueous solution of NaOH and the plating alloy layer was dissolved with a phosphoric acid aqueous solution, and with the Zn-based plating, the plating metal layer was further doped with a nitric acid aqueous solution. After the plating alloy layer was dissolved with an aqueous solution, it was visually observed. Regarding the evaluation of cracks, a score of 1 having no cracks was given, and a score of 5 which was enough to separate two cracks was given a score of 5, and the intervals between them were sensually classified into 3 grades.

[0031]

[Table 1]

[0032]

[Table 2]

[0033]

[Table 3]

[0034]

[Table 4]

[0035]

[Table 5]

[0036]

[Table 6]

As a result, the length of the alloy layer formed at the boundary between the hot-dip metal and the stainless steel plate to be plated was 5 mm per 1 mm.
No. with 0 or more cracks The samples of Nos. 1 to 42 had sound bending surfaces at 90 ° bending and showed good bendability without cracking. Especially 90 per 1 mm of alloy layer length
No. where this crack has occurred 2-12, No. 15
~ 20, No. 22-30, No. 32-33, No.
35-40, No. The samples of Nos. 43 to 46 showed a very good bendability without bending even when the bend surface was sound even when bent by 180 °. On the other hand, the length of the alloy layer was 1 mm without leveler straightening and skin pass rolling, which were carried out for comparison.
No. with less than 50 cracks per hit In the samples of Nos. 47 to 70, cracks exhibiting a brittle fracture surface were generated in both 90 ° bending and 180 ° bending.

[0038]

According to the present invention, it becomes possible to manufacture a hot dip ferritic stainless steel sheet having excellent bending workability. Conventionally, products with poor bending workability had to be reduced in yield, but the present invention increased product yield,
Industrial benefits are extremely high. Conventionally, hot-dip ferritic stainless steel has been manufactured mainly with the expectation that it will be used for light-worked members. However, even if it is used in a state where there is no crack, even if it is used without cracks, the risk of destruction due to frequent minor accidents such as stone collision cannot be wiped out and it is widely used. It was never done. In such a case, conventionally, hot-dip austenitic stainless steel using an austenitic stainless steel containing a large amount of Ni as a plating original plate has been used. According to the present invention, the bending workability of hot-dip ferritic stainless steel is improved,
Moreover, the risk of destruction, which has been a concern even in a simple accident, has been eliminated, so that there is no need for an expensive hot-dip austenitic stainless steel sheet containing Ni. Especially for roofing materials, since hot-dip ferritic stainless steel having a low coefficient of thermal expansion can be used, the design as a structure is facilitated. As described above, the economic effect indirectly obtained by the present invention is large.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a cross section of a plated portion of a plated stainless steel plate.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Hiroyuki Hiramatsu Inventor Hiroyuki Hiramatsu 1-1 Tobahata-cho, Tobata-ku, Kitakyushu, Fukuoka Inside the Nippon Steel Co., Ltd. Yawata Works (72) Kazuhiro Tano Inaba, Kitakyushu, Kitakyushu-shi, Fukuoka No. 1 town No. 1 Nippon Steel Corporation Yawata Works

Claims (10)

[Claims] 1. An alloy layer of the stainless steel and the hot dip plated metal is present at the interface between the surface of the ferritic stainless steel plated steel sheet and the hot dip plated layer, and cracks are present in the alloy layer. Hot-dip ferritic stainless steel sheet with excellent bending workability. 2. An alloy layer of the stainless steel and the hot dip plated metal is present in an area ratio of at least 60% or more at the interface between the ferritic stainless steel plated steel sheet and the hot dip plated layer, and is perpendicular to the surface of the hot dip plated steel sheet. Bending process characterized by having in the alloy layer 50 or more fine cracks having a length of 50% or more of the thickness of the alloy layer viewed from an arbitrary cross section per 1 mm length parallel to the surface of the steel plate to be plated. Hot-dip ferritic stainless steel sheet with excellent properties. 3. By weight%, C: 0.08% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, N: 0.03% or less, At least 60% or more in area ratio of the alloy layer of the stainless steel and the hot-dip galvanized metal is present at the interface between the hot-dip galvanized steel sheet and the ferritic stainless steel plated steel sheet with the balance being Fe and unavoidable impurities, and Characterized in that it has 50 or more fine cracks having a length of 50% or more of the thickness of the alloy layer viewed from an arbitrary cross section perpendicular to Hot-dip ferritic stainless steel sheet with excellent bending workability. 4. C: 0.08% or less by weight%, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, N: 0.03% or less, Further Nb: 1.5%
Hereinafter, Ti: 0.5% or less, Mo: 2.5% or less, Cu: 0.5% or less, one or two or more, and the balance is Fe and inevitable impurities. The alloy layer of the stainless steel and the hot-dip galvanized metal is present in the interface between the hot-dip galvanized layer and the hot-dip galvanized layer at an area ratio of at least 60% or more, and the thickness of the alloy layer is A hot-dip ferritic stainless steel sheet having excellent bending workability, which has 50 or more fine cracks having a length of 50% or more in the alloy layer per 1 mm in length parallel to the surface of the steel sheet to be plated. 5. The surface of the interface between the ferritic stainless steel plated steel sheet and the hot dip plated layer is subjected to hot dip coating in which an alloy layer of the stainless steel and hot dip plated metal is present in an area ratio of at least 60% or more, By adding a maximum elongation of 0.1% or more to the alloy layer of the plated steel sheet and the hot dip plated metal, a length of 50% or more of the thickness of the alloy layer as viewed from an arbitrary section perpendicular to the surface of the stainless steel plate to be plated. 1mm parallel to the surface of the steel plate to be coated with fine cracks
A method for producing a hot-dip ferritic stainless steel sheet having excellent bending workability, characterized in that 50 or more pieces are present in the alloy layer. 6. A hot-dip coating in which an alloy layer of the stainless steel and the hot-dip metal is present in an area ratio of at least 60% or more is applied to a boundary surface between the ferritic stainless steel plated steel sheet and the hot-dip plated layer, and 350 to 400 is applied. 5 to ℃ temperature
After holding for at least the time, by adding a maximum elongation of 0.1% or more to the alloy layer of the steel sheet to be plated and the hot dip plated metal, the alloy layer thickness of the alloy layer thickness as viewed from an arbitrary cross section perpendicular to the surface of the steel sheet to be plated is added. Hot-dip ferritic stainless steel sheet with excellent bending workability, characterized in that fine cracks having a length of 50% or more are present in the alloy layer at 50 or more per 1 mm length parallel to the surface of the steel sheet to be plated. Manufacturing method. 7. A balance of C: 0.08% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, N: 0.03% or less by weight%. Is applied to the interface between the ferritic stainless steel plated steel sheet consisting of Fe and unavoidable impurities and the hot-dip galvanized layer, and an alloy layer of the stainless steel and the hot-dip galvanized metal is present at an area ratio of at least 60% or more, and 350 5 to a temperature of ~ 400 ° C
After holding for at least the time, by adding a maximum elongation of 0.1% or more to the alloy layer of the steel sheet to be plated and the hot dip plated metal, 50% of the alloy layer thickness as seen from an arbitrary cross section perpendicular to the surface of the plated steel sheet. % Of 50% or more per minute 1 mm in length parallel to the surface of the steel sheet to be plated in the alloy layer. Manufacturing method. 8. By weight%, C: 0.08% or less, Si: 1.0% or less, Mn: 1.0% or less, Cr: 11 to 25%, N: 0.03% or less, Further Nb: 1.5%
Hereinafter, Ti: 0.5% or less, Mo: 2.5% or less, Cu: 0.5% or less, one or two or more, and the balance is Fe and inevitable impurities. The interface between the hot-dip galvanized layer and the hot-dip galvanized layer is subjected to hot-dip galvanizing in which the alloy layer of the stainless steel and the hot-dip galvanized metal is present at an area ratio of at least 60% or more, and the temperature is set to 350 to 400 ° C.
After holding for at least the time, by adding a maximum elongation of 0.1% or more to the alloy layer of the steel sheet to be plated and the hot dip plated metal, 50% of the alloy layer thickness as seen from an arbitrary cross section perpendicular to the surface of the plated steel sheet. % Of 50% or more per minute 1 mm in length parallel to the surface of the steel sheet to be plated in the alloy layer. Manufacturing method. 9. Skin pass rolling, rolls with a radius of 100 mm or less are used as a means for adding a maximum elongation of 0.1% or more.
One or more of bending-type leveler straightening and tension-type leveler straightening for passing more than one line are applied, and hot-dip stainless steel excellent in bending workability according to claim 4, 5, 6 or 7, respectively. Steel plate manufacturing method. 10. The hot dip plated metal is a metal containing Zn as a main component or a metal containing Al as a main component, according to claim 1, 2, 3, 4, 5, 6, 7, or 8. A hot-dip galvanized stainless steel sheet excellent in bending workability described in each of them or a method for producing the same.