JP2002020850A - Plated steel material having high corrosion resistance and excellent in workability, and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plated steel material with which the corrosion resistance and workability of a steel material for use under outdoor exposure, such as a building, embankment, finishing net and fence can be improved and to provide its manufacturing method. SOLUTION: The plated steel material which has high corrosion resistance and excellent workability, which has a plating layer having an average chemical composition consisting of, by mass, 4-20% Al, 0.8-5% Mg, <=2% Fe and the balance Zn and which also has, in the interface between the plating layer and base iron material, an alloy layer of <=20 μm thickness having a chemical composition consisting of, by mass, <=25% Fe, <=30% Al, <=5% Mg and the balance Zn can be provided. Its manufacturing method is also described.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plated steel material having improved corrosion resistance and workability of a steel material used by being exposed outdoors such as a building, seawall construction, a fish net, a fence and the like, and a method for producing the same. Plating steel materials include wire for wire mesh,
Concrete reinforcing fiber, bridge wire, PWS
Wires, PC steel wires, plated steel wires such as ropes, structural steel materials such as H-shaped steel, steel sheet piles, mechanical parts such as screws, bolts, springs, and steel products such as steel plates.

[0002]

2. Description of the Related Art Galvanized steel wires and zinc-aluminum alloy-plated steel wires having better corrosion resistance are used as plated steel materials, in particular, as plated steel wires. This zinc-aluminum alloy-plated steel wire is generally subjected to a cleaning treatment by washing, degreasing, etc. the steel wire, and then performing a flux treatment, followed by performing a hot-dip plating mainly comprising zinc as a first step, Z with 10% Al addition as a second stage
Hot-dip plating in n-Al alloy bath or direct A
It is manufactured by plating in a Zn-Al alloy bath having an addition amount of 10%, then vertically pulling up from the plating bath, cooling, and winding.

[0003] The zinc-aluminum alloy-plated steel wire has good corrosion resistance, but there is a method of increasing the plating thickness in order to further increase the corrosion resistance.
One of the methods to secure the required plating thickness is to increase the moving speed (linear speed) of the steel wire, pull up the steel wire from the plating bath at high speed, and apply the plating alloy to the steel wire due to the viscosity of the hot-dip alloy. There is a way to increase the amount. However, in this method, because of the high speed, the plating thickness is likely to be non-uniform in a cross section perpendicular to the longitudinal direction of the plated steel wire,
There is a limit in plating equipment. Therefore, in the case of galvanizing with current plating equipment or hot-dip galvanizing with a Zn-Al alloy, corrosion resistance cannot be said to be sufficient, and there is a strong demand for a longer life of plated steel wire. There is no problem.

[0004] In order to address this problem, Mg in a plating bath is used.
JP-A-10-226865 proposes a Zn-Al-Mg alloy-based plating composition in which the corrosion resistance is increased by adding Cu. The plating method based on this plating composition is based on the premise that thinning for steel sheets is used, and thick plating steel wires represented by steel wires used by exposing this method to buildings, seawalls, fish nets, fences, etc. When it is applied to a steel sheet, there is a problem that a crack occurs in a plated layer during processing of a plated steel wire. Japanese Patent Application Laid-Open No. 7-207421 discloses that Zn-
Although a method of thickening the Al-Mg alloy plating is described, when this method is applied as it is to the plating of the steel wire, the Fe-Zn alloy layer becomes thick, and the Fe-Zn alloy is formed during the processing of the plated steel wire. There are problems such as cracking of the alloy layer and peeling.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described various problems, and has been made in consideration of the above-mentioned problems. It is an object of the present invention to provide a plated steel wire excellent in workability in which cracks and peeling do not occur in a plating layer and / or a plating alloy layer, and a method for producing the same.

[0006]

Means for Solving the Problems The present inventors have conducted various studies on means for solving the above-mentioned problems, and as a result, have reached the present invention. The gist of the present invention is as follows. (1) In a plated steel material, Fe: 25% or less, Al: 30% or less, Mg: 5
% Or less and a balance of Zn and an alloy layer having a thickness of 20 μm or less, characterized by having high corrosion resistance and excellent workability. (2) In the plated steel material, the average composition is A
l: contains 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, and contains one or more elements selected from the following groups a, b, c, and d: , The balance being Zn at the plating layer-base iron interface.
e: 25% or less, Al: 30% or less, Mg: 5% or less, and one or more elements selected from each of the following a, b, c, and d groups, with the balance being Zn A plated steel material having high corrosion resistance and excellent workability, characterized by having an alloy layer having a thickness of 20 μm or less. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass. (3) In the plated steel material, the average composition is A
1: 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, having a plating layer composed of Zn, with the balance being high corrosion resistance and excellent workability as described in (1) above. Plated steel material. (4) The plating layer structure has an α phase mainly composed of Al—Zn, a single phase of Zn or a β phase composed of a Mg—Zn alloy phase,
And a plated steel material having high corrosion resistance and excellent workability according to any one of the above (1) to (3), wherein each of the ternary eutectic phases of Zn-Al-Mg exists. . (5) The plating layer structure has an α phase containing Al—Zn as a main component, a β phase composed of a Zn single phase or a Mg—Zn alloy phase,
And wherein each of the Zn-Al-Mg ternary eutectic phases is present and the volume fraction of the β phase is 20% or less, according to any one of the above items (1) to (4). Plating steel material with high corrosion resistance and excellent workability. (6) The above-mentioned (1) to (5), wherein the plated steel material further has one of a paint coating and a heavy corrosion protection coating.
A highly corrosion-resistant plated steel material according to any one of the above. (7) the heavy duty anticorrosion coating is made of vinyl chloride, polyethylene,
(6) characterized in that it is a coating of at least one polymer compound selected from polyurethane and fluororesin.
A plated steel material with high corrosion resistance and excellent workability as described. (8) The plated steel material having high corrosion resistance and excellent workability according to any one of the above (1) to (7), wherein the plated steel material is a plated steel wire. (9) In the method for producing a plated steel material, as a first step, the steel material is subjected to hot-dip galvanizing mainly composed of zinc, and then, as a second step, the average composition of the plating layer is expressed by mass%.
Al: 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, the balance being Zn, and by mass% at the plating layer-base iron interface, Fe: 25% or less, Al: 30% Hereinafter, M
g: hot-dip zinc alloy plating for forming an alloy layer of 5% or less, the balance being Zn and having a thickness of 20 μm or less, followed by cooling, which is characterized by high corrosion resistance and excellent workability. Production method. (10) In the method for producing a plated steel material, the steel material is subjected to hot-dip galvanizing mainly composed of zinc as the first step, and then, as the second step, the average composition is Al: 4 to
20%, Mg: 0.8 to 5%, Fe: 2% or less,
It has one or more elements selected from the following groups a, b, c, and d, and has a plating layer composed of a balance of Zn. 25%
Hereinafter, a thickness containing 30% or less of Al and 5% or less of Mg, and containing one or a plurality of elements selected from the following groups a, b, c, and d and a balance of Zn. 20
A method for producing a plated steel material having high corrosion resistance and excellent workability, characterized by applying a hot-dip zinc alloy plating for forming an alloy layer of μm or less, and thereafter cooling. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass. (11) The hot-dip galvanizing as the first step is performed by mass%
And (10) a method for producing a plated steel material having high corrosion resistance and excellent workability according to (10), wherein the hot-dip galvanizing contains 3% or less of Al and 0.5% or less of Mg. (12) In the step of applying the hot-dip galvanizing as the first step, and then applying the hot-dip zinc alloy plating as the second step, purging a portion where the plated steel material is pulled up from the plating bath is purged with nitrogen gas. The method for producing a plated steel material having high corrosion resistance and excellent workability according to the above (9) or (10), wherein oxidation of the surface and the plated steel material is prevented. (13) The hot-dip galvanizing as the first stage is applied with a plating bath immersion time of 20 seconds or less, and then the hot-dip zinc alloy plating as the second stage is applied with a plating bath immersion time of 20 seconds or less. The method for producing a plated steel material having high corrosion resistance and excellent workability according to the above (9) or (10). (14) After the second stage hot-dip zinc alloy plating, immediately after the coated steel wire is pulled up from the hot-dip zinc alloy plating bath, by direct cooling by any one of water spray, steam-water spray, or water flow, The method for producing a plated steel material having high corrosion resistance and excellent workability according to the above (9) or (10), wherein the plated alloy is solidified. (15) The high corrosion resistance as described in (8), (9) or (12) above, wherein the cooling start temperature at the time of cooling the plated steel wire is set to be equal to or lower than the melting point of the plated alloy + 20 ° C. A method for producing plated steel with excellent workability. (16) In the method for producing a plated steel material, the steel material is subjected to electrogalvanizing mainly composed of zinc as a first step, and then, as a second step, the average composition is Al: 4 to
20%, Mg: 0.8-5%, Fe: 2% or less, balance Z
A method for producing a galvanized steel material having high corrosion resistance and excellent workability, characterized by performing hot-dip zinc alloy plating comprising n and then cooling. (17) In the manufacturing method of the plated steel material, the steel material is subjected to electrogalvanization mainly composed of zinc as a first step, and then, as a second step, the average composition is Al: 4 to
20%, Mg: 0.8-5%, Fe: 2% or less, balance Z
A method for producing a plated steel wire having high corrosion resistance and excellent workability, wherein a zinc alloy powder comprising n is melted in a die, plated through the die, and then cooled. (18) In the method for producing a plated steel material, the steel material is subjected to electrogalvanization mainly composed of zinc as a first step, and then, as a second step, the average composition is Al: 4 to
20%, Mg: 0.8 to 5%, Fe: 2% or less,
High corrosion resistance characterized by applying a hot-dip zinc alloy plating containing one or more elements selected from the following groups a, b, c, and d, the balance being Zn, and then cooling. A method for producing a plated steel material having excellent workability. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass. (19) In the method for producing a plated steel material, the steel material is subjected to electrogalvanization mainly composed of zinc as a first step, and then, as a second step, the average composition is Al: 4 to
20%, Mg: 0.8 to 5%, Fe: 2% or less,
A zinc alloy powder containing one or a plurality of elements selected from the following groups a, b, c, and d, and the balance being Zn, is made into a molten state in a die, and plating is passed therethrough. A method for producing a plated steel material having high corrosion resistance and excellent workability, which is characterized by applying and then cooling. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a plated steel material of the present invention, particularly a plated steel wire will be described in detail. In the plated steel wire of the present invention, the average composition of the plating layer is, by mass%,
Al: 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, with the balance being Zn. Further, by mass% at the interface between the plating layer and the base iron, Fe: 25% or less, Al: 30 %Less than,
Mg: has an alloy layer of 5% or less, the balance being Zn and having a thickness of 20 μm or less. Further, in the plated steel wire of the present invention, an alloy layer composed of Fe: 25% or less, Al: 30% or less, Mg: 5% or less, and the balance of Zn at a thickness of 20 µm or less at the interface between the plating layer and the base iron. have. Further, the average composition of the plating layer is, in mass%, Al: 4 to 20%, M:
g: 0.8 to 5%, Fe: 2% or less, an element for improving corrosion resistance, an element for improving plating hardness, an element for refining plating structure,
It contains one or more of the plating processability improving elements, and the balance is made of Zn. First, the role and the content of the plating layer and the alloying elements forming the plating layer-base iron interface will be described.

[0008] At the interface between the plating layer and the ground iron, an alloy layer mainly composed of Fe-Zn is formed. Strictly speaking, the structure of the Fe—Zn alloy layer is expressed by mass%, Fe: 25% or less, Al: 3
An alloy layer composed of 0% or less, Mg: 5% or less, and the balance being Zn, and has a thickness of 20 μm or less. The Fe-Zn alloy layer plays a role in linking the plating with the ground iron. In addition to playing the role of plating, the elasticity of the plated alloy and the ground iron is affected when the ground iron undergoes deformation such as elastic deformation or plastic deformation. It has the effect of absorbing the difference in the deformation rate due to the difference in the rate or deformation resistance and preventing the plating from peeling off. On the other hand, Fe-Zn
The alloy layer has a brittle property, and if Fe exceeds 25%, the alloy layer is cracked at the time of processing and causes plating peeling, so the upper limit is set to 25%. The preferable addition amount of Fe is 2 to 25%. The presence of Al in this alloy layer provides ductility to the alloy layer, but when it exceeds 30%, a hardened phase is generated,
The upper limit is set to 30% in order to reduce the workability. Al
Is preferably 2 to 30%. Although Mg has an effect of improving the corrosion resistance of the alloy layer, it also causes embrittlement of the alloy layer. Therefore, the upper limit that does not cause embrittlement is 5%, so the upper limit is set to 5%. The preferable addition amount of Mg is 0.5 to
5%.

[0009] When the alloy layer is thick, the alloy layer is easily broken or the interface between the alloy layer and the ground iron or the interface between the alloy layer and the plating is easily broken. If the thickness of the plating alloy layer exceeds 20 μm, cracks increase and the plating cannot be put to practical use. Since the corrosion resistance of the alloy layer is originally lower than that of the plating layer, the alloy layer is preferably thinner and more preferably 10 μm or less. For the reasons described above, the upper limit of the thickness of the alloy layer is 20 μm which does not impair workability.
m, the thickness of the Fe—Zn alloy layer is set to 20 μm or less.

Next, the role and content of alloy elements in the plating layer will be described. Al enhances corrosion resistance,
It also has the effect of preventing oxidation of other elements in the plating layer.
%, The effect of preventing oxidation of Mg in the plating bath cannot be obtained. Further, when Al is added in excess of 20%, the formed plating layer becomes hard and brittle, so that processing cannot be performed. Therefore, the range of the addition amount of Al in the plating layer is set to 4 to 20%. In the case of plating a steel wire, the thickness is desirably set to 9 to 14% for thickening, and a stable plating layer can be obtained in this range.

[0011] Mg uniformly produces a corrosion product of plating, and the corrosion product containing Mg has an effect of inhibiting the progress of corrosion. Therefore, Mg has an effect of improving the corrosion resistance of the plating alloy. . However, if the addition is less than 0.8%, the effect of improving corrosion resistance cannot be obtained, while if it exceeds 5%, oxides are easily generated on the plating bath surface,
A large amount of dross is generated, making the plating operation difficult. In order to achieve both corrosion resistance and dross generation, the range of the added amount of Mg is set to 0.8 to 5%.

[0012] Fe may be eluted from the steel during plating or may be present as an impurity in the plated metal, but if it exceeds 2%, the corrosion resistance is reduced, so the upper limit was made 2%. Although there is no particular lower limit on the amount of Fe added, Fe may not be included in some cases. Further, in the present invention, one or more elements selected from the following groups a, b, c and d can be contained in addition to the above Al, Mg and Fe. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass.

Ti has an effect of improving corrosion resistance, and elements having the same effect include Li, Be, Na, K, and C.
a, Cu, La, Hf and the like. The corrosion resistance is improved by adding one or more of the elements in an amount of 0.01 to 0.5% by mass. If the content is less than 0.01%, no effect is recognized, and if the content exceeds 1.0%, phase separation may occur when the plating solidifies, so the content is set to 0.01 to 0.5%.

Mo has the effect of improving the hardness of the plating layer and making it less susceptible to damage, and W, Nb, Ta and the like having the same effect. By adding 0.2% by mass, the hardness of the plating layer is improved, and the plating layer is hardly damaged. Pb and Bi
Has the effect of making the crystals on the plating surface finer. In a plate having a large plating surface or a plated steel material such as a shaped steel, a crystal of a plating alloy grows largely on a plating surface and may look like a pattern. If Pb or Bi that does not form a solid solution in Zn and Fe is added to avoid this phenomenon, it becomes a solidification nucleus during plating to promote fine crystal growth and no pattern is generated. The range in which this effect can be obtained is 0.01 to 0.2.
% By mass.

Sr, V, Cr, Mn and Sn have the effect of improving workability. If it is less than 0.01%, the effect is not recognized, and if it exceeds 0.5%, segregation becomes remarkable and it becomes easy to crack when processing a plated steel material.
5%. Furthermore, in the plated steel material of the present invention, since Al and Mg are the main components, cooling after plating causes Al-Mg to be contained in the plating alloy layer (plating layer) outside the alloy layer existing at the plating-ground iron interface. Α mainly composed of Zn
Phase, a β phase comprising a Zn single phase or a Mg-Zn alloy phase,
And a ternary eutectic phase of Zn / Al / Zn-Mg can coexist. Among these, the presence of the ternary eutectic phase of Zn / Al / Zn-Mg can provide the uniform generation of corrosion products and the effect of preventing the progress of corrosion by the corrosion products. Further, the β phase is inferior in corrosion resistance as compared with other phases, so that it tends to cause local corrosion. And the volume ratio of the β phase is 20%
Exceeds 20%, which leads to a decrease in corrosion resistance.
The following is assumed.

The method for producing the plated steel material of the present invention includes:
Adopt the two-step plating method. As the first stage, hot-dip galvanizing mainly comprising zinc to form an Fe-Zn alloy layer,
Next, as a second step, the plated steel material of the present invention can be efficiently obtained by applying a hot-dip zinc alloy plating having an average composition specified in the present invention. As zinc used in hot-dip galvanizing as the first step, pure Zn or Zn
In order to prevent the oxidation of the plating bath and improve the fluidity, a small amount of misch metal, a zinc-based alloy bath added with Si, Pb, etc., and for the purpose of growing the plating alloy layer, A
A molten zinc alloy containing l: 3% or less and Mg: 0.5% or less can also be used. When the Fe—Zn alloy layer is obtained by the first-stage hot-dip galvanizing, when Al and Mg are contained in the Fe—Zn alloy layer, there is an effect that Al and Mg easily enter the plating alloy.

In the method for producing a plated steel material according to the present invention, the workability is improved by purging a portion where the plated steel material is pulled up from the plating bath with nitrogen gas to prevent oxidation of the plating bath surface and the plated steel material. Can be. If an oxide is generated on the plating surface immediately after plating, or if the generated oxide adheres to the plating bath surface,
During processing of a plated steel material, plating may be cracked with oxides as nuclei. Therefore, prevention of oxidation of the take-out portion is an important factor. In order to prevent oxidation, it is possible to use an inert gas such as argon or helium in addition to nitrogen. However, nitrogen is the best in terms of cost.

In the case where the plated steel material of the present invention is obtained by the two-step plating method, in order to make the growth of the plated alloy appropriate, as the first step, hot-dip galvanizing mainly composed of zinc is used.
It is necessary to perform the plating bath immersion time for 20 seconds or less, and then to apply the molten zinc alloy plating as the second stage for the plating bath immersion time of 20 seconds or less. From this, when plating is performed for a long time, the thickness of the alloy layer becomes thick and exceeds 20 μm. Therefore, as the first step, hot-dip plating mainly composed of zinc is performed in a plating bath immersion time of 20 seconds or less, As a second step, hot-dip zinc alloy plating is performed with a plating bath immersion time of 20 seconds or less.

Even when plating is performed for 20 seconds or less in the first plating bath and the alloy layer grows, the thickness of the alloy layer in the second stage hot-dip zinc alloy plating is not more than 20 seconds for the plating alloy bath immersion time. If the growth is small, the alloy layer thickness is 2
0 μm or less. In the present invention, as a specific cooling means to be subjected to a cooling treatment after the post-plating treatment, after the second stage hot-dip galvanized alloy plating, water spray immediately after pulling up the coated steel wire from the hot-dip zinc alloy plating bath. Means for solidifying the plating alloy by direct cooling passing through a deaeration cylinder provided with any one of means of water, water spray, or water flow is employed. Preferably, the cooling is performed by water spray or steam spray. By setting the cooling start temperature at this time to the melting point of the plating alloy + 20 ° C., a stable plating layer can be obtained. FIG. 1 shows the relationship between the number of cracks in a winding test of a wire or a steel wire depending on the presence / absence of a gas cut in the gas cut cylinder. Using a plating bath of the same composition, a winding test was performed on a plated steel wire under the same conditions except for the presence or absence of a cylinder to cut off, and the number of surface cracks was compared. It can be seen that the disconnected cylinder shows a great effect.

The composition of the plated steel material used in the present invention is applicable as long as it is a low-carbon steel material. Typically, C: 0.02 to 0.25 in mass%.
%, Si: 1% or less, Mn: 0.6% or less, P: 0.0
A steel material containing 4% or less, S: 0.04% or less, the balance being Fe and unavoidable impurities is preferable. In the present invention, the surface of the plated steel wire is finally coated with a coating, or a heavy-duty anticorrosive coating is applied as a coating of at least one polymer compound selected from vinyl chloride, polyethylene, polyurethane and fluororesin. Thereby, the corrosion resistance can be further improved.

Although the present invention has been described with reference to plated steel materials, particularly steel wires, it is needless to say that the present invention can be sufficiently applied to steel plates, steel pipes, steel structures, and the like.

[0022]

<Example 1> Steel wire JIS G 3505
A 4 mm diameter steel wire having the surface of SWRM 6 subjected to pure Zn plating was subjected to Zn-Al-Mg based zinc alloy plating under the conditions shown in Table 1 and evaluated. For comparison, plating composition, Fe-Z
Those with different n alloy layers were similarly evaluated. All the insides of the disconnected cylinders were purged with nitrogen gas using the disconnected cylinders.
Observation of the plating structure was performed by polishing the C section of the plating wire and then applying EPMA.
Was observed. In the composition analysis of the alloy layer, a quantitative analysis was performed with a beam diameter of 2 μm. The corrosion resistance was determined by the amount of corrosion of the plating per unit area from the weight difference before and after the test with continuous salt spraying for 250 hours as the corrosion weight loss. In this test, 20 g /
The m ² or less was judged acceptance as acceptable.

The workability was evaluated by making the prepared plated wire 6 mm.
The wire was wound six times around a steel wire having a diameter, and the surface thereof was visually observed to determine the presence or absence of cracks. Further, after the cellophane tape was attached to the sample after crack determination, the presence or absence of peeling of the plating was observed when the sample was peeled off, and one or less cracks and no peeling were regarded as pass conditions. Table 1 shows the relationship between the plating composition, the alloy layer composition, the structure of the thickness plating, and the β-phase volume ratio with the corrosion resistance, workability, and dross formation of the plating bath. All of the examples of the present invention exhibited good corrosion resistance and workability, and generated little dross.

In Comparative Examples 1 to 5, the plating alloy compositions were out of the range of the present invention. In Comparative Examples 1 and 2, the amount of Al or Mg was lower than the lower limit, and the corrosion resistance was poor. Comparative Examples 3 to 5 are inferior in corrosion resistance when the amount of Al or Mg is higher than the upper limit. Comparative Examples 6 and 7 were cases where the thickness of the plating alloy layer was out of the range of the present invention, and resulted in poor workability. In Comparative Examples 8 to 10, the β phase in the plating structure was out of the range of the present invention, and the corrosion resistance was poor.

[0025]

[Table 1]

<Example 2> A steel wire rod of 4 mm in diameter with pure Zn plated on the surface of JIS G 3505 SWRM6 was plated with Zn-Al-Mg based zinc alloy under the conditions shown in Table 2 and evaluated. As a comparison, those having different plating compositions and Fe-Zn alloy layers were similarly evaluated. All the insides of the disconnected cylinders were purged with nitrogen gas using the disconnected cylinders. The plating structure was observed by EPMA after polishing the C section of the plating wire. In the composition analysis of the alloy layer, a quantitative analysis was performed with a beam diameter of 2 μm. The corrosion resistance was defined as the amount of corrosion of the plating per unit area from the weight difference before and after the test with continuous salt spraying for 250 hours as the corrosion weight loss. In this test, 20 g / m ² or less was judged as pass and pass / fail was judged.

The workability was evaluated by making the prepared plated wire 6 m long.
It was wound around a steel wire having a diameter of m six times, and the surface was visually observed to determine the presence or absence of cracks. Further, after the cellophane tape was stuck to the sample after crack determination, the presence or absence of peeling of the plating was observed when the sample was peeled off, and the pass condition was one crack or less and no peeling. Table 3 shows the relationship between the plating composition, the alloy layer composition, the structure of the thickness plating, the β-phase volume ratio, the corrosion resistance, the workability, and the dross formation of the plating bath. All of the examples of the present invention exhibited good corrosion resistance and workability, and generated little dross.

In Comparative Examples 11 to 15, the plating alloy compositions are out of the range of the present invention. In Comparative Examples 11 and 12, the amount of Al or Mg was lower than the lower limit, and the corrosion resistance was poor. Comparative Examples 13-1
In No. 5, the corrosion resistance is inferior to the upper limit in the amount of Al or Mg. Comparative Examples 16 and 17 were cases where the thickness of the plating alloy layer was out of the range of the present invention, and resulted in poor workability. Comparative Example 18
In Nos. To 20, the β phase in the plating structure is out of the range of the present invention, and the corrosion resistance is poor.

FIG. 1 shows the effect of the disconnected cylinder. Using a plating bath of the same composition, a winding test was performed on a plated steel wire under the same conditions except for the presence or absence of a cylinder to cut off, and the number of surface cracks was compared. It can be seen that the disconnected cylinder shows a great effect.

[0030]

[Table 2]

[0031]

[Table 3]

[0032]

As described above, according to the present invention, a galvanized steel material having high corrosion resistance and excellent workability, particularly,
Galvanized steel wire can be obtained.

[Brief description of the drawings]

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a diagram showing a relationship between a gas cut after plating and the number of cracks in a winding test of a wire or a steel wire.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Seiji Nishida 1 Kimitsu, Kimitsu City, Chiba Prefecture Inside Nippon Steel Corporation (72) Inventor Akira Takahashi 1 Kimitsu, Kimitsu City, Chiba Prefecture Nippon Steel Corporation (72) Inventor Atsuhiko Yoshie 20-1 Shintomi, Futtsu-shi, Chiba Nippon Steel Corporation Technology Development Division (72) Inventor Kazumi Nishimura 1 Fujimachi, Hirohata-ku, Himeji-shi, Hyogo New Japan F-term in Hirohata Works (reference) 4F100 AB02A AB02C AB03B AB09A AB09C AB10A AB10C AB12A AB12C AB18A AB18C AB20A AB20C AB23A AB23C AB31A AB31C AB40A AB40C AK04D AK15D AK17D AK51D BA03E EJ602 GB04 GB07 JA11A JB02D JL01 4K027 AA02 AA05 AA06 AA22 AB02 AB05 AB26 AB33 AB34 AB44 AC33 AC52 AC72 AC82 AE03 AE18 A E27 AE33 AE36 4K044 AA02 AB02 AB04 BA10 BA21 BB03 BC02 BC05 CA11 CA53

Claims (19)

[Claims] 1. In a plated steel material, Fe: 25% or less, Al: 30% or less, by mass% at a plating layer-base iron interface.
Mg: a plated steel material having high corrosion resistance and excellent workability, characterized by having an alloy layer of 5% or less and a balance of Zn having a thickness of 20 µm or less. 2. The plated steel material has an average composition of 4 to 20% Al, 0.8 to 5% Mg, and Fe:
2% or less, and one or more elements selected from each of the following groups a, b, c, and d, with the balance being Zn
With a plating layer consisting of
And Fe: 25% or less, Al: 30% or less, Mg: 5%
And an alloy layer containing one or more elements selected from the following groups a, b, c, and d, and having a balance of Zn and having a thickness of 20 μm or less. A plated steel material with excellent corrosion resistance and workability. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass. 3. The plated steel material has an average composition in mass% of Al: 4 to 20%, Mg: 0.8 to 5%, Fe:
2. A plated steel material having high corrosion resistance and excellent workability according to claim 1, wherein the plated steel material has a plating layer composed of 2% or less, with the balance being Zn. 4. The plating layer structure includes an α phase mainly composed of Al—Zn, a β phase composed of a Zn single phase or a Mg—Zn alloy phase, and a Zn—Al—Mg ternary eutectic phase. The plated steel material according to any one of claims 1 to 3, which has high corrosion resistance and excellent workability. 5. The plating layer structure includes an α phase mainly composed of Al—Zn, a β phase composed of a Zn single phase or a Mg—Zn alloy phase, and a Zn—Al—Mg ternary eutectic phase. The plated steel material having high corrosion resistance and excellent workability according to any one of claims 1 to 4, wherein the steel has a volume fraction of β phase of 20% or less. 6. The steel plate according to claim 1, further comprising one of a coating and a heavy-duty coating.
5. The highly corrosion-resistant plated steel material according to any one of 5. 7. The high corrosion resistant and processed material according to claim 6, wherein said heavy duty anticorrosion coating is at least one polymer compound coating selected from vinyl chloride, polyethylene, polyurethane and fluororesin. Plated steel with excellent resistance. 8. The plated steel material having high corrosion resistance and excellent workability according to claim 1, wherein the plated steel material is a plated steel wire. 9. A method for producing a plated steel material, wherein the steel material is subjected to hot-dip galvanizing mainly composed of zinc as a first step, and then, as a second step, the average composition of the plating layer is expressed as 4-20%, Mg: 0.8-5%, F
e: 2% or less, the balance being Zn, and the plating layer
Fe: 25% or less, Al: 30%
Hereinafter, Mg: 5% or less, thickness of 20 μm composed of the balance Zn
A method for producing a plated steel material having high corrosion resistance and excellent workability, characterized by applying a hot-dip zinc alloy plating for forming the following alloy layer, and then cooling. 10. A method for producing a plated steel material, wherein the steel material is subjected to hot-dip galvanizing mainly comprising zinc as a first step, and then to a second step, wherein the average composition is A
l: contains 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, and contains one or more elements selected from the following groups a, b, c, and d: , The balance being Zn at the plating layer-base iron interface.
e: 25% or less, Al: 30% or less, Mg: 5% or less,
And zinc alloy plating for forming an alloy layer having a thickness of 20 μm or less and containing one or more elements selected from each of the following groups a, b, c, and d and comprising a balance of Zn And then cooling the coated steel. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass. 11. The hot-dip galvanizing as the first stage is hot-dip galvanizing containing 3% or less of Al and 0.5% or less of Mg by mass%.
A method for producing a plated steel material having the above described high corrosion resistance and excellent workability. 12. A step of applying the hot-dip galvanizing as the first step and then applying the hot-dip galvanized alloy plating as the second step, purging a portion where the plated steel material is pulled up from a plating bath with nitrogen gas, The oxidation of the plating bath surface and the plating steel material is prevented.
Or the method for producing a plated steel material having high corrosion resistance and excellent workability according to 10 above. 13. The hot-dip galvanizing as the first step is performed with a plating bath immersion time of 20 seconds or less, and then the hot-dip zinc alloy plating as the second step is performed with a plating bath immersion time of 20 seconds or less. 9. The method according to claim 9, wherein:
0. A method for producing a plated steel material having high corrosion resistance and excellent workability according to 0. 14. After the second stage hot-dip zinc alloy plating,
The plating alloy is solidified by direct cooling by any one of water spray, steam-water spray, and water flow immediately after the plated steel wire is lifted from the hot-dip zinc alloy plating bath, or 11. The method for producing a plated steel material having high corrosion resistance and excellent workability according to item 10. 15. The high corrosion resistance and workability according to claim 8, 9 or 12, wherein a cooling start temperature at the time of cooling the plated steel wire is set to a melting point of the plated alloy + 20 ° C. or less. Manufacturing method of excellent plated steel. 16. A method for producing a plated steel material, wherein the steel material is subjected to electrogalvanizing mainly composed of zinc as a first step, and then, as a second step, the average composition is A
l: 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, hot-dip zinc alloy plating comprising the balance of Zn, and then cooling, characterized by high corrosion resistance and excellent workability Method of manufacturing plated steel. 17. A method for producing a plated steel material, wherein the steel material is subjected to electrogalvanizing mainly composed of zinc as a first step, and then, as a second step, the average composition is A
l: 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, a zinc alloy powder consisting of the balance Zn is melted in a die, plated to pass through the die, and then cooled. A method for producing a plated steel wire having high corrosion resistance and excellent workability. 18. A method for producing a plated steel material, wherein the steel material is subjected to electrogalvanizing mainly composed of zinc as a first step, and then to a second step, the average composition of which is A
l: contains 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, and contains one or more elements selected from the following groups a, b, c, and d: A method of producing a galvanized steel material having high corrosion resistance and excellent workability, characterized by applying a hot-dip zinc alloy plating comprising the balance of Zn and then cooling. a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass. 19. A method for producing a plated steel material, wherein the steel material is subjected to electrogalvanizing mainly composed of zinc as a first step, and then, as a second step, the average composition is A
l: contains 4 to 20%, Mg: 0.8 to 5%, Fe: 2% or less, and contains one or more elements selected from the following groups a, b, c, and d: A method for producing a plated steel material having high corrosion resistance and excellent workability, characterized in that a zinc alloy powder consisting of the balance Zn is melted in a die, plated to pass through the die, and then cooled. . a: Ti, Li, Be, Na, K, Ca, Cu, La,
One or more elements of Hf are each added at 0.01 to
1.0% by mass. b: One or more elements of Mo, W, Nb, and Ta are each contained in an amount of 0.01 to 0.2% by mass. c: One or more elements of Pb and Bi are each contained in an amount of 0.01 to 0.2% by mass. d: One or more elements of Sr, V, Cr, Mn, and Sn are each contained in an amount of 0.01 to 0.5% by mass.