Plated steel wire, wire mesh, and wire mesh products

Abstract

The present invention provides plated steel wire with excellent corrosion resistance, slip resistance, and workability, as well as wire mesh and wire mesh products using the plated steel wire. [Solution] A plated steel wire and its application comprising a base steel wire and a plating layer covering the surface of the base steel wire, wherein the plating layer has a composition of, by mass%, Al: 4.0% to 15.0%, Mg: 0.30% to 4.00%, the remainder being Zn and impurities, the maximum value of the circumferential roughness Rz of the surface of the plating layer is 10.0 μm to 100.0 μm, the average particle size of the primary Al part in the plating layer is 2.0 μm to 18.0 μm, and the hardness of the plating layer is 100 Hv to 220 Hv.

Description

Technical Field

[0001] The present disclosure relates to plated steel wires, wire meshes, and wire mesh products.

Background Art

[0002] Plated steel wires are used as materials for wire meshes, fences, transmission wires, etc. A plated steel wire includes a base steel wire and a plating layer formed on the surface of the base steel wire.

[0003] For example, in revetment work, a cage mat for revetment work is installed so that it does not slip even when a person rides on it after construction. A wire mesh is one of the members of the cage mat for revetment work. The material used for this wire mesh is a plated steel wire, and a Zn-plated steel wire obtained by wire drawing, annealing, and zinc (Zn) plating of a wire rod having a steel composition containing almost no C is generally used.

[0004] The properties required for the material of a wire mesh used for a cage mat for revetment work or the like are frictional performance and corrosion resistance. For example, in Patent Document 1, in a plated steel wire having a plating alloy with an average composition of Al: 4 to 20%, Mg: 0.8 to 5%, and the balance Zn on the surface of the steel wire, the maximum value Rmax of the circumferential roughness of the plating surface is 60 to 300 μm, and a plated steel wire having high corrosion resistance and excellent workability, which has an Fe-Zn alloy layer of 20 μm or less at the plating-base metal interface, is disclosed.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] When plated steel wire is used, for example, as the material for the wire mesh of a gabion mat used in seawall construction, it is thought that deformation may occur due to people walking on it, making it slippery. While the plated steel wire disclosed in Patent Document 1 takes into account processability, corrosion resistance, and friction characteristics, a plated steel wire with superior friction performance and corrosion resistance is desirable.

[0007] In view of the above issues, this disclosure aims to provide plated steel wire with excellent corrosion resistance, slip resistance, and workability, as well as wire mesh and wire mesh products using the plated steel wire. [Means for solving the problem]

[0008] The above objectives will be achieved by the following means: <1> Base material steel wire, The plated layer covers the surface of the base steel wire, The aforementioned plating layer has a composition consisting of, by mass%, Al: 4.0% to 15.0%, Mg: 0.30% to 4.00%, and the remainder being Zn and impurities. The maximum value of the roughness Rz in the circumferential direction of the surface of the plating layer is 10.0 μm or more and 100.0 μm or less. In the aforementioned plating layer, the average particle size of the primary Al crystal is 2.0 μm or more and 18.0 μm or less. The hardness of the aforementioned plating layer is 100 Hv or more and 220 Hv or less. Plated steel wire. <2> The aforementioned plating layer includes an Fe-Al alloy layer with a thickness of 40 μm or less at the interface with the base steel wire. <1> The plated steel wire described above. <3> The aforementioned plating layer, in place of a portion of the Zn, by mass%, Si: 0.50% or less, Cr: 0.50% or less, Pb: 0.50% or less, Bi: 0.50% or less, V: 0.50% or less, Mn: 0.50% or less, Sn: 0.50% or less, Ti: 0.50% or less Na: 0.50% or less, K: 0.50% or less, Cu: 0.50% or less, and, Fe: 2.00% or less, Includes at least one selected from the group consisting of, <1> or <2> The plated steel wire described above. <4> For wire mesh <1> ~ <3> Plated steel wire as described in any one of the following. <5> <1> ~ <4> A wire mesh made by bundling plated steel wires as described in any one of the following. <6> <5> A wire mesh product that includes the wire mesh described above, such as a fence or cage mat. [Effects of the Invention]

[0009] According to this disclosure, it is possible to provide plated steel wire with excellent corrosion resistance, slip resistance, and workability, as well as wire mesh and wire mesh products using the plated steel wire. [Brief explanation of the drawing]

[0010] [Figure 1] This is an SEM image showing an example of a cross-section of the alloy layer at the interface between the plating layer and the base steel wire. [Modes for carrying out the invention]

[0011] An example embodiment of this disclosure is described in detail below. In this specification, the percentage (%) indicated for the content of each element in the chemical composition means "mass percent". The amount of each element in a chemical composition is sometimes expressed as "amount." For example, the amount of carbon (C) may be expressed as "amount of C." A numerical range expressed using "~" means a range that includes the numbers before and after "~" as the lower and upper limits, respectively. However, if the numbers before and after "~" are preceded by "greater than" or "less than," the numerical range means a range that does not include those numbers as the lower or upper limit. In the numerical ranges described step by step in this specification, the upper limit value of a certain stepwise numerical range may be replaced with the upper limit value of the numerical range described in other stepwise descriptions, and the lower limit value of a certain stepwise numerical range may be replaced with the lower limit value of the numerical range described in other stepwise descriptions. Also, the upper limit value or the lower limit value may be replaced with the value shown in the examples. The term "process" includes not only an independent process but also a process that cannot be clearly distinguished from other processes as long as the intended purpose of the process is achieved.

[0012] The inventors have conducted studies to create a plated steel wire with improved corrosion resistance for steel wires used outdoors, such as wire meshes, cage mats for revetment works, and fishing nets. Normally, a zinc - aluminum - magnesium alloy plated wire is made from a hot - rolled wire rod. After removing the scale on the surface of the hot - rolled wire rod and performing a surface coating treatment, it is cold - worked by a die to the desired wire diameter to obtain a drawn steel wire. Next, after surface activation treatment such as degreasing, pickling, and flux treatment as a pre - plating treatment process for the drawn steel wire, it is first immersed in a molten metal bath mainly composed of zinc to apply a plating layer, and then immersed in a zinc - aluminum - magnesium alloy bath as the second step, and pulled vertically out of the plating bath and cooled to be manufactured.

[0013] On the other hand, the surface of the plated steel wire used for wire meshes, cage mats for revetment works, fishing nets, etc. has roughness applied to the surface so that people do not slip when walking on it after construction. The roughness of the surface of the plated steel wire can be obtained by rapid cooling during plating solidification. However, if the cooling rate is too fast, the workability will decrease and cracks in the plating will occur. Therefore, it is required to control the hardness and crack density of the plating layer.

[0014] As a result of diligent research by the present inventors, it was found that, in a ternary alloy plating composition containing Zn, Al, and Mg, setting the average grain size of Al crystals precipitated as the primary crystal of the zinc alloy plating layer to 2.0 μm or more and 18.0 μm or less significantly affects not only the corrosion resistance of the plated wire surface but also the frictional performance of the surface. The Al primary crystal portion of the plating layer corrodes preferentially, but the corrosion rate can be reduced by refining the Al primary crystal. Furthermore, when the Al primary crystal portion is refined, the surrounding structure of the Al primary crystal is also refined, thus improving the hardness of the plating layer. By manufacturing a wire mesh using this plated steel wire, deformation of the plating layer during use can be suppressed. This led to the discovery that a wire mesh with excellent slip resistance can be obtained by optimizing not only the corrosion resistance of the plating layer but also its hardness, thus completing this disclosure. For example, in the case of plated steel wire used in infrastructure projects such as gabion mats for revetment construction, where high corrosion resistance is required, increasing the cooling rate brings the average particle size of the primary Al crystals within the aforementioned range, thereby sufficiently increasing the hardness of the plating layer while also imparting roughness to the surface of the plating layer. As a result, the plated steel wire according to this disclosure serves as an anti-slip surface when people move on it after installation.

[0015] [Plated steel wire] The details of the plated steel wire related to this disclosure are described below. The plated steel wire relating to this disclosure includes a base steel wire (which may be simply referred to as "steel wire" in this specification) and a plating layer that covers the surface of the base steel wire. The plating layer contains Al, Mg, and Zn, and has a composition (plating composition) of Al: 4.0% to 15.0% by mass, Mg: 0.30% to 4.00%, and the remainder being Zn and impurities. The plating layer may also contain some of the elements described later in place of a portion of the Zn. Furthermore, the maximum circumferential roughness (Rz) of the surface of the plating layer is 10.0 μm or more and 100.0 μm or less, the average particle size of the primary Al crystals in the plating layer is 2.0 μm or more and 18.0 μm or less, and the hardness of the plating layer is 100 Hv or more and 220 Hv or less. The base steel wire and plating layer will be described in detail below.

[0016] <Base material steel wire> The base steel wire in the plated steel wire according to this disclosure is mainly composed of Fe (iron) and contains elements such as C, Si, Mn, P, and S. The composition, structure, and mechanical properties of the base steel wire are not particularly limited and can be selected according to the application of the plated steel wire. For example, known base steel wires used in wire mesh such as gabion mats for seawall construction and fishing nets can be used. Examples of the chemical composition of the base steel wire in the plated steel wire relating to this disclosure include, but are not limited to, the following elements and their contents.

[0017] (An example of the chemical composition of the base steel wire) C: 0.01~0.30% Si: 0.10~1.00% Mn: 0.10~1.00% P:0.030% or less S: 0.030% or less N: 0.0150% or less O: 0.0070% or less Al: 0.080% or less Cr:1.50% or less B: 0.0050% or less Ti: 0.040% or less Mo: 0.40% or less V: 0.30% or less Cu: 0.50% or less Ni: 0.50% or less Nb: 0.10% or less Remainder: Fe and impurities

[0018] In the example chemical composition shown above, P, S, N, and O are included as impurities, while Al, Cr, B, Ti, Mo, V, Cu, Ni, and Nb are arbitrary elements (they may be 0%). Furthermore, impurities refer to substances that are introduced during the industrial manufacturing of steel wire from raw materials such as ore, scrap, or the manufacturing environment, and are permissible to the extent that they do not adversely affect (i.e., do not impair) the plated steel wire relating to this disclosure.

[0019] The following elements and their quantities may be included as optional elements in the base steel wire. Mg: 0.010% or less Zr: 0.010% or less Sb: 0.015% or less W: 0.010% or less REM (elements with atomic numbers 57 to 71): 0.005% or less Hf: 0.005% or less Ta: 0.050% or less Ca: 0.005% or less Sn: 0.050% or less Bi:0.050% or less Te: 0.050% or less Zn: 0.050% or less Co:0.10% or less

[0020] The diameter of the base steel wire is not particularly limited and can be selected according to the application of the plated steel wire. For example, when the plated steel wire according to this disclosure is used for wire mesh such as gabion mats for seawall construction or fishing nets, the diameter of the base steel wire can range from 1.0 to 5.0 mm, but the diameter of the base steel wire is not limited to this range.

[0021] <Plating layer> Next, the plating layer of the plated steel wire related to this disclosure will be described. The inventors diligently investigated the influence of the plating structure on the frictional performance and corrosion resistance of the surface of plated steel wire in a ternary alloy plating composition containing Zn, Al, and Mg. As a result, they found that the grain size of Al crystals (primary Al crystals) precipitated as the primary crystals in the zinc-aluminum-magnesium alloy plating layer greatly affects corrosion resistance, while the roughness and hardness of the plating layer greatly affect frictional performance. The plating layer of the plated steel wire according to this disclosure may include an alloy layer, as described below, at the interface with the base steel wire. In this disclosure, the alloy layer is considered to be part of the plating layer, but it may be described as "the alloy layer at the interface between the plating layer and the base metal (base steel wire)."

[0022] (Plating composition) The plating layer in this disclosure is composed of a ternary alloy having a composition mainly of Zn, with Al: 4.0% to 15.0% and Mg: 0.30% to 4.00%. The plating layer may also contain any elements described later.

[0023] Al: 4.0~15.0% Al in the plating layer has the effect of stabilizing corrosive products and is an element that enhances corrosion resistance. Since it is difficult to obtain a corrosion resistance improvement effect when the Al content in the plating is less than 4.0%, the Al content in the plating layer should be 4.0% or more. On the other hand, if the Al content exceeds 15.0%, the primary Al crystals become coarser, and corrosion resistance decreases. Therefore, the Al content in the plating layer should be capped at 15.0%. The Al content in the plating layer is preferably 5.0-13.5%, more preferably 6.0-12.5%.

[0024] Mg: 0.30~4.00% Magnesium (Mg) in the plating layer has the effect of stabilizing corrosive products and is an element that enhances corrosion resistance. Since it is difficult to obtain a corrosion resistance improvement effect when the Mg content in the plating layer is less than 0.30%, the Mg content in the plating layer should be 0.30% or more. On the other hand, if the Mg content exceeds 4.00%, the plating layer becomes excessively hard, making processing such as wire mesh production difficult. Therefore, the Mg content in the plating layer should be capped at 4.00%. The Mg content in the plating layer is preferably 0.50 to 3.50%, and more preferably 0.75% to 3.00%.

[0025] Remainder: Zn and impurities The remainder of the plating layer composition consists of Zn and impurities, or Zn, an arbitrary element described later, and impurities. The impurities are elements other than Zn, Mg, and Al contained in the plating bath (excluding the arbitrary elements described later), and are not components intentionally added to the plating bath during the plating process, but rather components (elements) that are unintentionally mixed in due to the raw materials or manufacturing process, and the elements and their content do not affect the corrosion resistance or fatigue properties of the plating. The content of impurity elements contained in the plating layer as impurities depends on the impurity element, but the content of a single component (element) is preferably 0.1% or less. Furthermore, the upper limit of the total content of impurity elements contained in the plating layer is within a range that does not adversely affect the effects of this disclosure, and specifically it is preferably 1.0% or less, more preferably 0.1% or less, and particularly preferably less than 0.01%.

[0026] The plating layer may contain any element in place of a portion of Zn, as long as it does not adversely affect the effects of this disclosure. Specifically, the plating layer may contain: Si: 0.50% or less, Cr: 0.50% or less, Pb: 0.50% or less, Bi: 0.50% or less, V: 0.50% or less, Mn: 0.50% or less, Sn: 0.50% or less, Ti: 0.50% or less Na: 0.50% or less, K: 0.50% or less, Cu: 0.50% or less, and, Fe: 2.00% or less, It may contain one or more selected from the group consisting of the following. These optional elements may or may not be included in the plating layer, or they may be included within the above-mentioned content range. Of these optional elements, the first group below contributes to processability, and the second group below contributes to corrosion resistance.

[0027] (Group 1) Si:0.50% or less The Si content in the plating layer may be 0%. Si in the plating layer has the effect of thinning the thickness of the alloy layer at the interface between the plating layer and the base metal (base steel wire), and is an element that contributes to improving the workability of the plated steel wire. To obtain this effect, it is desirable to add 0.01% or more Si. On the other hand, if 0.50% or more Si is added, a coarse Mg-Si phase is formed, and the workability actually decreases. Therefore, when the plating layer contains Si, the Si content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0028] Cr:0.50% or less The Cr content in the plating layer may be 0%. Cr in the plating layer has the effect of thinning the thickness of the alloy layer at the interface between the plating layer and the base metal (base steel wire), and is an element that contributes to improving the workability of the plated steel wire. To obtain this effect, it is desirable to add 0.01% or more Cr. On the other hand, if 0.50% or more Cr is added, the workability will actually decrease. Therefore, when the plating layer contains Cr, the Cr content is preferably 0.01 to 0.50%, and more preferably 0.04 to 0.40%.

[0029] Pb: 0.50% or less The Pb content in the plating layer may be 0%. Pb in the plating layer has the effect of suppressing cracking during processing and contributes to improving the workability of plated steel wire. To obtain this effect, it is desirable to add 0.01% or more Pb. On the other hand, if more than 0.50% Pb is added, the workability actually decreases. Therefore, if the plating layer contains Pb, the Pb content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0030] Bi:0.50% or less The Bi content in the plating layer may be 0%. Bi in the plating layer has the effect of suppressing cracking of the plating during processing and is an element that contributes to improving the workability of plated steel wire. To obtain this effect, it is desirable to add 0.01% or more Bi. On the other hand, if more than 0.50% Bi is added, the workability will actually decrease. Therefore, when Bi is included in the plating layer, the Bi content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0031] V: 0.50% or less, The V content in the plating layer may be 0%. V in the plating layer has the effect of suppressing cracking of the plating during processing and is an element that contributes to improving the workability of plated steel wire. To obtain this effect, it is desirable to add 0.01% or more V. On the other hand, if more than 0.50% V is added, the workability will actually decrease. Therefore, when V is present in the plating layer, the V content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0032] Mn: 0.50% or less, The Mn content in the plating layer may be 0%. Mn in the plating layer has the effect of suppressing cracking during processing and contributes to improving the workability of plated steel wire. To obtain this effect, it is desirable to add 0.01% or more Mn. On the other hand, adding 0.50% or more Mn actually reduces workability. Therefore, when the plating layer contains Mn, the Mn content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0033] Sn: 0.50% or less The Sn content in the plating layer may be 0%. Sn in the plating layer has the effect of suppressing cracking of the plating during processing and is an element that contributes to improving the workability of plated steel wire. To obtain this effect, it is desirable to add 0.01% or more Sn. On the other hand, if 0.50% or more Sn is added, the workability will actually decrease. Therefore, when the plating layer contains Sn, the Sn content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0034] (Second group) Ti: 0.50% or less The Ti content in the plating layer may be 0%. Ti in the plating layer enhances corrosion resistance and contributes to improving the corrosion resistance of plated steel wire. To achieve this effect, it is desirable to add 0.01% or more Ti. On the other hand, adding 0.50% or more Ti can actually decrease workability. Therefore, when the plating layer contains Ti, the Ti content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0035] Na: 0.50% or less The Na content in the plating layer may be 0%. Na in the plating layer has the effect of enhancing corrosion resistance and is an element that contributes to improving the corrosion resistance of plated steel wire. To obtain this effect, it is desirable to add 0.01% or more Na. On the other hand, if more than 0.50% Na is added, the workability will actually decrease. Therefore, if the plating layer contains Na, the Na content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0036] K: 0.50% or less The potassium (K) content in the plating layer may be 0%. K in the plating layer enhances corrosion resistance and contributes to improving the corrosion resistance of plated steel wire. To achieve this effect, it is desirable to add 0.01% or more K. On the other hand, adding 0.50% or more K can actually decrease workability. Therefore, when the plating layer contains potassium (K), the K content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0037] Cu: 0.50% or less The copper content in the plating layer may be 0%. Copper in the plating layer enhances corrosion resistance and contributes to improving the corrosion resistance of plated steel wires. To achieve this effect, it is desirable to add 0.01% or more copper. On the other hand, adding 0.50% or more copper can actually decrease workability. Therefore, when the plating layer contains Cu, the Cu content is preferably 0.01 to 0.50%, and more preferably 0.05 to 0.40%.

[0038] Fe:2.00% or less Fe is an optional element in the plating layer and may not be present at all. In other words, the Fe content may be 0%. During the manufacturing process of plated steel wire, Fe from the base steel wire may be incorporated into the plating layer. In this case, Fe forms an alloy layer. The alloy layer enhances the corrosion resistance of the plated steel wire. Even a small amount of Fe content will provide some degree of the above effect. However, if the Fe content exceeds 2.00%, an excessive alloy layer will be formed. In this case, the workability of the plated steel wire will decrease. Therefore, the Fe content in the plating layer is 0% or more and 2.00% or less, and if Fe is present, it is 2.00% or less. The preferred lower limit of the Fe content is 0.01%, more preferably 0.05%, more preferably 0.10%, and still more preferably 0.15%. The preferred upper limit of the Fe content in the plating layer is 1.90%, more preferably 1.75%, and still more preferably 1.50%.

[0039] The compositional analysis of the plating layer is performed in accordance with JIS H0401:1999 "Test Method for Hot-Dip Galvanizing," by immersing the plated wire in 1000 ml of hydrochloric acid solution to dissolve the plating layer. The weight before dissolution is taken as W1 and the weight after dissolution as W2, and the dissolved weight of the plating layer is determined to five decimal places in grams. The amount of Al, Zn, and Mg in the dissolution solution is then quantified in g / l concentrations by ICP (Inductively Coupled Plasma) emission spectroscopy, and the composition can be determined using the following formula. If the plating layer contains an alloy layer, the alloy layer is also dissolved and analyzed, and the results are used as the composition of the plating layer. Al concentration (%): Al value of analysis / (W1 - W2) × 100 Mg concentration (%): Analytical value Mg / (W1 - W2) × 100 Zn concentration (%): Analytical value of Zn / (W1 - W2) × 100

[0040] The plated steel wire according to this disclosure contains a plated alloy having a composition within the above range, thereby suppressing a decrease in friction performance and becoming a plated steel wire with excellent corrosion resistance.

[0041] (Maximum value of the circumferential roughness Rz of the plated layer surface) The maximum value of the circumferential roughness Rz of the surface of the plating layer of the plated steel wire according to this disclosure (maximum roughness) is 10.0 μm or more and 100.0 μm or less. The circumferential roughness of the plated layer surface contributes to the anti-slip properties, i.e., the friction characteristics, of the plated steel wire. When the maximum value of the circumferential roughness Rz of the plated layer surface is 10.0 μm or more and 100.0 μm or less, sufficient friction characteristics are present and it can function as an anti-slip surface. When the maximum value of the circumferential roughness Rz of the plated layer surface is 10.0 μm or more, it is easier to obtain the function of anti-slip properties. Furthermore, when the maximum value of the circumferential roughness Rz of the plated layer surface is 100.0 μm or less, the effective surface area is adjusted, thus improving corrosion resistance. For this reason, the upper limit for the maximum value of the circumferential roughness Rz of the plated layer surface is 100.0 μm. Preferably, the maximum value of the circumferential roughness Rz of the plated layer surface is 15.0 μm or more and 90.0 μm or less, and more preferably 20.0 μm or more and 80.0 μm or less.

[0042] The circumferential roughness Rz of the plated layer surface is measured by the following method. Surface roughness Rz is measured using a Keyence laser microscope (Keyence, product name: Laser Microscope VK-X250). A scan is performed perpendicular to the longitudinal direction of the plated steel wire at an arbitrary position on the outer surface of the plated layer. The scanning range is the entire length of the plated steel wire perpendicular to the longitudinal direction (circumferential direction) at 1000x magnification. Noise is removed from the obtained scan data by selecting the height cut level, and then the arc is corrected to a plane by selecting quadratic surface correction in surface shape correction. The roughness Rz is calculated in this way. The same process is performed at four arbitrary positions, and the maximum value is taken as the maximum roughness Rz.

[0043] (Average grain size of the primary Al crystal) The average particle size of the primary Al portion (which may be simply referred to as "primary Al portion" in this specification) included in the plating layer in this disclosure is 2.0 μm or more and 18.0 μm or less. The primary Al crystals are formed during the solidification of the plating solution that adheres to the surface of the base steel wire during the cooling process, as described later. The primary Al crystals in the plating layer are preferentially corroded in the early stages of corrosion; therefore, the presence of coarse primary Al crystals reduces corrosion resistance. To obtain sufficient corrosion resistance, the average particle size of the primary Al crystals should be 18.0 μm or less. If the average particle size of the primary Al crystals is excessively small, the hardness increases too much, and the processability decreases. For this reason, the average particle size of the primary Al crystals should be 2.0 μm or more. More preferably, it should be between 3.0 μm and 16.0 μm.

[0044] The average particle size of the primary Al crystals in the plating layer is measured by the following method. The plated steel wire is roughly polished with alcohol on a cross section perpendicular to its longitudinal direction (C section), and then polished to a mirror finish with diamond. Water is not used at this stage, as it may corrode the primary Al crystals. The plated layer on the C section is observed using a scanning electron microscope (SEM) to obtain backscattered electron images and observe the primary Al crystals. Primary Al crystals, which have a large proportion of the light element Al, appear as spherical or rod-shaped black images in the backscattered electron images. The backscattered electron images are taken at 1000x magnification, centered on the plated layer. Images are taken at four locations at 90° intervals. The obtained images are printed, and the primary Al crystals are traced onto a transparent sheet (OHP film) to create new electron images. The colored areas (primary Al crystals) in the obtained images are binarized, and the equivalent circle diameter is measured using image analysis software (image-j ver.1.51). The average of the equivalent circle diameters obtained from the four fields of view is taken as the average grain size of the primary Al crystals.

[0045] (Hardness of the plating layer) The plated steel wire relating to this disclosure has a plating layer hardness of 100 Hv or more and 220 Hv or less. The hardness of the plating layer contributes to suppressing the decrease in roughness during use of the plated steel wire, i.e., to the anti-slip effect (sometimes referred to as "slip resistance" in this specification). If the hardness of the plating layer is less than 100 Hv, the roughness decreases during use, making it difficult to obtain an anti-slip effect. Therefore, the lower limit of the hardness of the plating layer is 100 Hv. On the other hand, if the hardness of the plating layer exceeds 220 Hv, the workability decreases. Therefore, the upper limit of the hardness of the plating layer is 220 Hv. The hardness of the plating layer is more preferably 110 Hv to 200 Hv, and even more preferably 115 Hv to 190 Hv.

[0046] The hardness of the plating layer is measured by the following method. The plated steel wire is roughly polished with alcohol on a cross section perpendicular to its longitudinal direction (C section), and then polished to a mirror finish with a diamond. Water is not used at this stage, as it may corrode the primary Al crystals. The Vickers hardness is measured by pressing an indenter into the plated portion of the C section with a load of 25 gf. The indentation is aimed at the center of the thickness of the plating layer (i.e., midway between the surface of the base steel wire and the surface of the plating layer), and measurements are taken at eight points on the outer circumference of the plating layer at 45-degree intervals. The average value is taken as the hardness of the plating layer. If the plating layer contains an alloy layer at the interface with the base steel wire, the measurement is taken aiming at the center of the thickness of the plating layer excluding the alloy layer.

[0047] (Fe-Al alloy layer) The plated steel wire according to this disclosure may include an alloy layer of Fe and Al (referred to as "Fe-Al alloy layer" or simply "alloy layer" in this disclosure) at the interface between the plating layer and the base steel wire (base metal). The thickness of the Fe-Al alloy layer is preferably 40 μm or less. If the thickness of the Fe-Al alloy layer exceeds 40 μm, the Fe-Al alloy layer may crack, or the interface between the Fe-Al alloy layer and the base metal, or the interface between the Fe-Al alloy layer and the plating layer other than the alloy layer, may crack, resulting in reduced workability. The thickness of the Fe-Al alloy layer is more preferably 1 μm to 37 μm, and even more preferably 2 μm to 35 μm.

[0048] The thickness of the Fe-Al alloy layer can be measured by the following method. The plated steel wire is roughly polished with alcohol on a cross section perpendicular to its longitudinal direction (C section), and then polished to a mirror finish with diamond. Water is not used at this stage because it may corrode the primary Al crystals. The plated layer on the C section is observed using a scanning electron microscope (SEM) to obtain a backscattered electron image. The Fe-Al interface alloy layer, which has a large proportion of the light element Al, appears as a black image in the backscattered electron image. The Fe-Al alloy layer is a region that is not spherical but nearly parallel to the steel. The backscattered electron image is taken at 500x magnification, focusing on the boundary between the steel and the plated layer. Images are taken at four locations at 90° intervals. The thickness of the alloy layer is measured on the image at three locations: the center of the image and 50 μm away to the left and right. The average value of the four fields of view (12 locations in total) is taken as the thickness of the Fe-Al alloy layer. Figure 1 is an SEM image showing an example of a cross section of the alloy layer at the interface between the plated steel wire and the base steel wire according to this disclosure.

[0049] [Manufacturing method for plated steel wire] An example of a method for manufacturing plated steel wire related to this disclosure is described below. The method for manufacturing plated steel wire according to this disclosure is not particularly limited, but the plated steel wire according to this disclosure can preferably be manufactured by a method including a base steel wire preparation step, a first plating step, and a second plating step.

[0050] <Preparation process for base steel wire> In the base steel wire preparation process, the base steel wire to be plated is prepared. The steel wire can be manufactured using known methods. The steel wire may be manufactured by the plated steel wire manufacturer or supplied by a third party. The steel wire is manufactured by drawing the wire rod. Annealing treatment may be performed on the steel wire after drawing.

[0051] <First Plating Process> In the first plating process, zinc plating is performed on the steel wire prepared in the base steel wire preparation process. In the first plating process, a zinc plating layer is formed on the surface of the base steel wire, which serves as the base for the alloy plating layer. This improves the adhesion of the alloy plating layer to the base steel wire in the subsequent second plating process. The method of zinc plating is not particularly limited. The zinc plating may be hot-dip galvanizing or electroplating. Pickling and / or flux treatment may be performed on the steel wire before zinc plating. Pickling and / or flux treatment are optional and do not have to be performed. Pickling and / or flux treatment can improve the adhesion of the zinc plating layer to the base steel wire.

[0052] <Second Plating Process> In the second plating process, a hot-dip galvanizing treatment is performed on the base steel wire on which the zinc plating layer has been formed. The second plating process includes a hot-dip galvanizing treatment process and a cooling process, and may include a pre-treatment process before the hot-dip galvanizing treatment process.

[0053] The pretreatment step is optional and may or may not be performed. If the pretreatment step is performed, the base steel wire, which has a zinc plating layer formed after the first plating step, is subjected to pickling and / or flux treatment.

[0054] In the hot-dip galvanizing process, the base steel wire, which has a zinc plating layer formed in the first plating process, is immersed in a plating bath to achieve the desired plating composition and undergoes hot-dip galvanizing.

[0055] As the plating bath, a plating bath containing components corresponding to the composition of the plating layer to be formed on the surface of the base steel wire is used. Specifically, a plating bath having the same composition as the plating layer to be formed, such as Al: 4.0-15.0%, Mg: 0.3-4.0%, and the remainder: Zn, can be used. The plating bath may also contain the aforementioned optional elements (excluding Fe) as needed.

[0056] The temperature of the plating bath during the molten plating process is, for example, 400-500°C. The immersion time is, for example, 3-60 seconds.

[0057] In the cooling process, the base steel wire is removed from the plating bath and cooled. By starting water cooling within 20°C of the solidification temperature during the cooling process, the surface of the plating layer can be given a roughness such that the maximum roughness Rz in the circumferential direction of the plating layer surface falls within the aforementioned range. When using water cooling, the cooling rate should be an average rate of 15°C / second to 40°C / second from the cooling start temperature up to 350°C to refine the primary Al crystal to the aforementioned average grain size. Subsequently, below 350°C, the plating layer hardness can be obtained by cooling at an average rate of 10°C / second to 40°C / second. The cooling method below 350°C may be either water cooling or air cooling. Through the above process, plated steel wire according to this disclosure can be manufactured.

[0058] [Application] The uses of the plated steel wires relating to this disclosure are not limited. Because the plated steel wires relating to this disclosure have excellent corrosion resistance, slip resistance, and workability, they can be suitably used, for example, as a material (plated steel wire) for wire mesh made by bundling plated steel wires together. Specifically, because the plated steel wires relating to this disclosure can suppress the deterioration of friction performance even when stepped on by people, wire mesh made by bundling plated steel wires can be suitably used as fishing nets, outdoor fences, gabion mats for revetment construction, etc. If wire mesh made using the plated steel wires relating to this disclosure is used as gabion mats for revetment construction, the deterioration of friction performance due to deformation caused by people walking on it can be suppressed, slip resistance can be suppressed over a long period of time, and safety can be maintained. Furthermore, the plated steel wire according to this disclosure can be used for purposes other than wire mesh, and can be suitably used as a material for bridge wires, guard wires used to prevent the collapse of highways and bridge girders, etc. [Examples]

[0059] The following describes in more detail the embodiments of plated steel wire relating to this disclosure, but the plated steel wire, wire mesh, and wire mesh products relating to this disclosure are not limited to the embodiments described below.

[0060] [Manufacturing of plated steel wire] (Level 1A) A base steel wire (wire diameter: 2.0 mm) and a plating bath with the following composition were prepared. As the base steel wire, a steel wire having the chemical composition of mild steel wire rod specified in JIS G3505:2017 was prepared. Specifically, a wire rod with a wire diameter of 5.5 mm was prepared. The wire rod was drawn, and then annealed to produce a steel wire with a wire diameter of 2.0 mm.

[0061] (Composition of the plating bath used in the first plating process) Zn: 100% (Composition of plating bath 1 used in the second plating process) Al: 11.0% Mg: 2.0% Zn: remainder

[0062] A plating layer was formed on the base steel wire through the following first and second plating processes.

[0063] (First plating process) The first plating process was carried out using the prepared steel wire and the plating bath used in the first plating process. First, the steel wire was pickled and then flux-treated. After flux treatment, the steel wire was subjected to hot-dip galvanizing to form a zinc plating layer on the surface of the steel wire.

[0064] (Second plating process) The second plating process was carried out using the steel wire on which a zinc plating layer had been formed in the first plating process and the plating bath 1 used in the second plating process. The steel wire on which the zinc plating layer had been formed was subjected to flux treatment under the same conditions as in the first plating process. After that, the steel wire after the flux treatment was immersed in the prepared plating bath and a hot-dip plating process was carried out. At this time, the temperature of the plating bath was 460°C and the immersion time was 15 seconds. The cooling start temperature when the molten-plated steel wire was removed from the plating bath was set to the solidification temperature of the plating bath + 15°C. The plating layer was formed by cooling at a rate of 25°C / second up to 350°C and at a rate of 23°C / second below 350°C. Plated steel wire (level 1A) was manufactured through the above process.

[0065] The composition of the plating layer of the manufactured plated steel wire was analyzed using the method described above, and the composition was as shown in Table 1 below (unit: mass%, remainder: Zn). "-" indicates that the component is not present or is below the analytical limit. Furthermore, in each table, values ​​that fall outside the range of the plated steel wire (or the desirable range for manufacturing conditions) related to this disclosure are underlined.

[0066] [Table 1]

[0067] (Level 1B~1J) In the second plating process at level 1A, the conditions for removing the steel wire from the plating bath 1 and cooling it were changed to B to J (A: conditions for level 1A) as shown in Table 2-1 to form the plating layer. The meaning of the descriptions in Table 2-1 is as follows. Cooling start temperature: The temperature at which the base steel wire is removed from plating bath 1 and cooling begins. Solidification temperature: The temperature at which the plating bath 1 solidifies. Cooling rate A1: Average cooling rate from the cooling start temperature to 350°C Cooling rate A2: Average cooling rate below 350℃

[0068] In addition, at level 1J, an electroplating process was performed in the first plating step to form a zinc plating layer.

[0069] [Table 2-1]

[0070] [Analysis of the plating layer] Table 2-2 shows the results of the analysis of the composition of the plating layers at levels 1B to 1J.

[0071] [Table 2-2]

[0072] Furthermore, the circumferential roughness Rz of the plated layer surface, the average particle size of the primary Al crystal, and the hardness of the plated layer were measured using the method described above.

[0073] [evaluation] The manufactured plated steel wires were evaluated for slip resistance, corrosion resistance, and workability using the following methods.

[0074] -Slip resistance- The slip resistance of plated steel wire was evaluated using the following method. The test was conducted using the method described in KIPT0903 (Surface Friction Test Method). A wire mesh (2.0m x 2.0m) was formed by arranging plated steel wire, and the coefficient of friction was measured by moving a sliding piece at a normal speed of 100mm / min in a wet state. The total mass of this sliding piece was 30kg, and the part in contact with the wire mesh was made of rubber as specified in JIS T 8101:2020, with a contact area of ​​450cm². 2 (Long side 30cm, short side 15cm) If the coefficient of friction is 0.9 or higher, the slip resistance is judged to be sufficient (○), and if it is less than 0.9, the slip resistance is judged to be insufficient (×).

[0075] -Corrosion resistance- The corrosion resistance of plated steel wire was evaluated using the following method. The test was conducted in accordance with the neutral salt spray cycle test described in JIS H 8052:1999. Both ends of the plated steel wire were cured with resin to prevent corrosion from occurring and progressing from the ends of the test specimen. The neutral salt spray cycle test was conducted under the conditions specified in JASO M609. Specifically, the following steps were performed under the conditions specified in JASO M609. (Step 1: Salt spraying process) The test specimen is placed inside the test chamber. The temperature inside the test chamber is set to 35±1℃, and the spray solution is a 5% NaCl aqueous solution. The spray solution is continuously sprayed inside the test chamber for 2 hours. (Process 2: Drying process) Stop spraying the spray solution. Then, with the test specimen still inside, maintain the temperature inside the test chamber at 60±1°C and the relative humidity RH at 25%±5% for 4 hours. (Step 3: Wetting process) With the test specimen still inside, maintain the temperature inside the test chamber at 50±1℃ and the relative humidity RH at 95% or higher for 2 hours. The process was carried out in the order of steps 1, 2, and 3, and steps 1-3 constituted one cycle, which was repeated 30 times. After 30 cycles, the corrosion loss of each test specimen was measured. The amount of corrosion per unit area of ​​the plating was defined as the difference in weight before and after the test. A corrosion loss of 50 g / m² was considered. 2 If the result was less than the threshold, it was considered a pass, and the pass / fail decision (Pass: ○, Fail: ×) was made.

[0076] -Workability- The processability of plated steel wire was evaluated using the following method. The manufactured plated steel wire was cut to a length of 200 mm and wrapped around a 6.0 mm diameter steel wire four times. At this time, the wrapping direction was adjusted to be as perpendicular as possible to the longitudinal direction of the core material. During wrapping, the test pieces were wrapped spirally around the core material so that they did not overlap and the gaps between adjacent test pieces were kept as small as possible. The surface was visually inspected to determine whether or not the plating had peeled off. If no peeling of the plating layer was observed, it was considered a pass / fail (pass: ○, fail: ×).

[0077] The results are shown in Table 3.

[0078] [Table 3]

[0079] Levels 1A-1C and 1J met the requirements of this disclosure, and all evaluations were favorable. Level 1D resulted in insufficient surface roughness of the plated layer because water cooling was started while the solidification temperature was still high during the plating process. Level 1E indicates that the cooling rate was high during the plating process, resulting in refinement of the primary Al crystal and reduced processability. In level 1F, the surface roughness of the plated layer decreased because the cooling during solidification in the plating process was done by air cooling. Level 1G indicates that the cooling rate during solidification in the plating process was low, resulting in a decrease in the hardness of the plated layer. Level 1H indicates that the cooling rate during solidification in the plating process was high, resulting in a finer microstructure, increased hardness of the plating layer, and reduced workability. Level 1I resulted in a low cooling rate during solidification in the plating process, leading to coarsening of the primary Al crystals and reduced corrosion resistance.

[0080] [Manufacturing of plated steel wire] (Level 2A~18A) A base steel wire (wire diameter: 2.0 mm) and plating baths 2 to 18 with modified compositions were prepared, and a plating layer was formed according to manufacturing method A, the same as level 1A shown in Table 2-1.

[0081] [Analysis of the plating layer] When the composition of the plating layer of the manufactured plated steel wire was analyzed using the method described above, it was found to have the composition shown in Table 4 below (unit: mass%, remainder: Zn).

[0082] [Table 4]

[0083] Furthermore, the circumferential roughness Rz of the plated layer surface, the average particle size of the primary Al crystal, and the hardness of the plated layer were measured using the method described above.

[0084] [evaluation] The manufactured plated steel wires were evaluated for slip resistance, corrosion resistance, and workability using the methods described above. The results are shown in Table 5.

[0085] [Table 5]

[0086] Levels 2A through 14A met the requirements of this disclosure, and all evaluations were favorable. Level 15A resulted in excessive Al content in the plating layer, causing the primary Al crystals to coarse and reducing corrosion resistance. Level 16A showed insufficient Al content in the plating layer, resulting in the absence of primary Al crystals and reduced workability. Level 17A showed insufficient Mg content in the plating layer, resulting in insufficient hardness and reduced slip resistance. Furthermore, corrosion resistance was also reduced. Level 18A resulted in excessively high Mg content in the plating layer, leading to excessive hardness and reduced workability.

Claims

1. Base material steel wire, The plated layer covers the surface of the base steel wire, The aforementioned plating layer has a composition consisting of, by mass%, Al: 4.0% to 15.0%, Mg: 0.30% to 4.00%, and the remainder being Zn and impurities. The maximum value of the roughness Rz in the circumferential direction of the surface of the plating layer is 10.0 μm or more and 100.0 μm or less. In the aforementioned plating layer, the average particle size of the primary Al crystal is 2.0 μm or more and 18.0 μm or less. The hardness of the aforementioned plating layer is 100 Hv or more and 220 Hv or less. Plated steel wire.

2. The plated steel wire according to claim 1, wherein the plating layer includes an Fe-Al alloy layer having a thickness of 40 μm or less at the interface with the base steel wire.

3. The aforementioned plating layer, in place of a portion of the Zn, by mass%, Si: 0.50% or less, Cr: 0.50% or less, Pb: 0.50% or less, Bi: 0.50% or less, V: 0.50% or less, Mn: 0.50% or less, Sn: 0.50% or less, Ti: 0.50% or less Na: 0.50% or less, K: 0.50% or less, Cu: 0.50% or less, Fe: 2.00% or less, The plated steel wire according to claim 1, comprising at least one selected from the group consisting of the following.

4. A plated steel wire according to claim 1 or claim 2, for use in wire mesh.

5. A wire mesh made by bundling plated steel wires according to claim 1 or claim 2.

6. A wire mesh product which is a fence or cage mat including the wire mesh described in claim 5.

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