KR20100053364A - Hot dipping mild and steel wires - Google Patents

Abstract

PURPOSE: Hot dipping mild and steel wires are provided to improve the strength of the plated layer and prevent the corrosion by controlling the micro-structure of the plated layer. CONSTITUTION: A hot dipping mild wire is plated with a molten plating solution, one of molten zinc, molten zinc-aluminum alloy and molten Zn-Al-Mg-Si alloy. The hot dipping mild wire contains one or more of Sc, Y, Zr, Hf, and Er to promote nucleation so that isotropic fine grains are formed uniformly.

Description

Hot dipping mild and steel wires

The present invention relates to hot-dip galvanized wires and steel wires installed in outdoor exposed places, and in particular, trace nucleation to promote nucleation in hot-dip zinc, zinc-aluminum alloys and Zn-Al-Mg-Si-based alloy plating The present invention relates to hot-dip iron wires and steel wires in which the promoting elements are added alone or in combination so that they act as nucleation sites when forming the plating layer so that the crystal grains are formed into a fine and uniform process structure.

Steel wires or steel wires used in gabions, fences, fishing nets, overhead wires, etc. installed in outdoor exposed places are very important in terms of durability, corrosion resistance, high strength, etc. The plating layer is formed in the base metal.

The plating layer is formed on the surface of the metal by immersing the base metal in the plating bath in which the metal is molten, in order to exhibit the above characteristics, the adhesion to the base metal and uniformity of the thickness should be excellent, and the plating layer itself The intensity should also be high.

Generally, the base metal uses iron wire or steel wire, and the iron wire and the steel wire on which the plating layer is formed are called hot-dip iron wire and steel wire. These types are classified into hot dip galvanized iron wires and steel wires, and hot dip galvanized aluminum and Zn-Al-Mg-Si based alloy plated wires and steel wires having better corrosion resistance. Here, the description will focus on hot-dip galvanized-aluminum alloy plated wire and steel wire having excellent corrosion resistance.

 The molten zinc-aluminum alloy plated iron wire and steel wire are generally subjected to flux treatment after the base metal is cleaned and cleaned by a degreasing step. Hot-dip plating is first performed by zinc-based hot dip plating, followed by a two-step manufacturing process of finally hot-dip galvanizing in a Zn- (4-10 wt.%) Al alloy bath and Zn- (4-10 wt.%). It is divided into a one-step manufacturing process which is finished by one hot dip plating in Al alloy bath.

These hot dip galvanized-aluminum alloy wires and steel wires have satisfactory corrosion resistance, but in practical use, if the plated layer is damaged due to a strong impact from the outside and is lost, it may provide a fatal defect to the entire installation, no matter how local. .

For example, in applications such as gabions, not only the corrosion resistance of the plating layer but also the adhesion between the plating layer and the base metal, the hardness and workability of the plating layer itself should be considered as important factors. This is because, in practical use, much damage to the plated steel wire is inevitable. Therefore, in order to increase resistance by external impact, two methods of increasing the thickness of the plating layer methodically and imparting or strengthening the characteristics required to increase the resistance to damage to the plating layer itself can be taken.

First, the same method as the former may transfer the steel wire and the steel wire in the plating bath while rapidly depositing it, thereby increasing the viscosity with the molten plating liquid to increase the amount of the molten plating liquid attached to the steel wire. However, in this method, the thickness of the plating layer becomes thick and cracking or peeling phenomenon occurs in the plating layer, or due to the rapid flux, irregular plating thickness tends to be formed in the vertically vertical section of the plating iron wire and steel wire. There is. In addition, due to staying in the plating bath for a relatively long time during the hot-dip plating process, the layer of Fe-Zn intermetallic compound formed at the interface of the base metal becomes thick, so that brittleness and ductility decrease, causing cracks in the plating layer during manufacture or use. Product defects such as peeling or peeling.

As a result, it is judged that sufficient plating layer thickness cannot be secured with the current hot dip plating equipment. On the other hand, some of the Zn-Al-Mg ternary alloy plating component added Mg has been proposed, but as a result of the formation of a thin plated layer was found to improve the corrosion resistance to some extent, but generally required thick for gabions, etc. When applied to the iron wire and steel wire of the plating layer, cracks occurred in the plating layer. In order to solve the above problems, various studies have been conducted. However, if the thickness of the plating layer is increased, the layer of the Fe-Zn intermetallic compound, which is a reaction product at the interface, may be thickened to overcome defects such as cracking or peeling of the plating layer. There was no.

Therefore, it may be an effective alternative to impart or enhance the properties required to increase the resistance to damage to the plating layer itself, as in the latter. Therefore, while increasing the strength of the plating layer itself, it is necessary to have adhesiveness and workability such that there is no problem in practical use.

 Therefore, the present invention adds a small amount of nucleation promoters that promote nucleation in molten zinc, zinc-aluminum alloy and Zn-Al-Mg-Si alloy plating alone or in combination, so that these additional elements are nucleated upon solidification of the plating layer. It is intended to provide a hot-dip galvanized iron wire and a steel wire in which a plating layer formed of a fine and uniform process structure is formed by acting as a production site.

In order to achieve the above object, the present invention, the molten zinc, molten zinc-aluminum alloy and molten Zn-Al-Mg-Si-based alloys in the molten plating solution consisting of any one of the components of promoting the nucleation Sc, Y, Zr, Hot-dip iron wires and steel wires are characterized by consisting of a process structure in which any one of Hf and Er is added alone or in combination of two or more, to promote nucleation upon forming a plating layer, and uniformly form isotropic microcrystal grains. .

In addition, the nucleation promoting element preferably contains Sc: 0.01-1.0, Y: 0.01-1.0, Zr: 0.01-1.0, Hf: 0.01-1.0, Er: 0.01-1.0 by weight.

By the said subject solving means, this invention can manufacture the plated iron wire and steel wire which are excellent in adhesiveness and workability, while being high in the strength of a plating layer by controlling the microstructure of a plating layer. As mentioned in the necessity of the present invention, such plated wires and steel wires are very suitable for applications in which the plated layer may be damaged due to external force or impact in practical use, and may also prevent damage accidents that may arise from inadvertent construction. have. In particular, since the primary purpose of the hot-dip iron and steel wire is to prevent the corrosion of the base metal from the corrosive environment, the stability and reliability of the plating layer will determine the performance of the entire installation. Therefore, the improvement of the characteristics of the plating layer itself is connected to the improvement of the performance of the entire facility, it can be said that it is very important to improve the quality of the product, improve the reliability, and prevent unexpected safety accidents.

   In addition, although the present invention relates to steel wires and steel wires, it is a technology that can be suitably applied to pipes, steel sheets and other structures, and therefore a large ripple effect is expected in the entire industry.

The present invention adds a small amount of nucleation accelerating elements to the molten zinc, zinc-aluminum alloy and Zn-Al-Mg-Si-based alloy plating components to obtain a process structure in which fine isotropic crystal grains are uniformly formed. It is to provide a hot-dip galvanized wire and steel wire to improve the adhesion, strength and workability of the plating layer.

In the existing hot dip galvanizing (GI-based) and zinc-aluminum alloy (Galfan-based, Galvalume-based) and Zn-Al-Mg-Si-based alloy plating components, as the nucleation promoting element, Sc: 0.01 ~ 1.0 weight ratio, Y : 0.01 to 1.0 weight ratio, Zr: 0.01 to 1.0 weight ratio, Hf: 0.01 to 1.0 weight ratio, Er: 0.01 to 1.0 weight ratio, any one or a combination of two or more thereof.

When a small amount of the nucleation-promoting elements are added alone or in combination, the nucleation is promoted upon solidification of the molten plating solution, thereby miniaturizing the coagulation cell structure, and finally obtaining a uniform and fine grain process structure. From this, the adhesiveness, strength, and workability of the plating layer can be improved.

Here, the components of the nucleation-promoting elements Sc, Y, Zr, Hf, and Er are all 0.01 to 1.0 wt. This is because the reactivity with Al and Mg elements increases rapidly, forming a brittle intermetallic compound reacted with the base metal component and the plating component, which adversely affects the plating layer. In addition, when less than 0.01% is added, the effect cannot be expected.

Based on the above, the hardness values and the winding test results of the specimens prepared by the specific examples of the present invention are summarized in Table 1 and Table 2, respectively.

Sample Nos. 1 to 8 shown in Table 1 are alloy plating components proposed in the present invention, and Nos. 9 to 14 are conventionally known as comparative materials. In other words, a molten plating solution is prepared by adding appropriate amounts of the nucleation-promoting elements Sc, Y, Zr, Hf, and Er, alone or in combination, to various existing hot-dip plating components in any combination of at least 0.01% to 1.0%. And the steel wires were plated by a conventional method, and then the hardness characteristics of the plated layers were examined.

At this time, the plating layer was uniformly prepared to maintain the thickness of about 20㎛ in all conditions. The hardness test piece was prepared by mirror-processing the cross section of the plated steel wire, and measured using a micro vickers. Hardness measurement was mainly performed 5 times in the region of the zeta phase area where coagulation tissue is well developed to remove the highest value and the lowest value, and was determined as the average value of the remaining measurements.

As can be seen from Table 1, in the case of the invention according to the present invention it can be seen that it shows a very high hardness characteristics compared to the conventional comparative material. When the added element was added up to 1.0%, hardness value of about 280Hv was obtained, which showed a hardness increase of about 50% compared with the general hardness value of the existing comparative material.

In addition, as a result of examining the microstructure, the process material of fine isotropic crystal grains was observed in the invention material, but the coarse columnar dendrite structure was observed in the comparative material.

In conclusion, it can be said that the difference in hardness characteristics of the invention and the comparative material is due to the difference in the respective solidification structures. That is, by adding a small amount of nucleation-promoting elements that promote nucleation, which is the proposal of the present invention, these elements act as nucleation sites during the solidification of the plating solution to promote nucleation, resulting in a fine grain structure. It is believed that the same process organization contributed to the increase in hardness.

<Table 1>

Alloy plating component (wt.%) Hardness (Hv)
Zeta layer sample
number Zn Al Mg Si MM Sc Y Zr Hf Er foot
persons
ashes One bal. 3 0.5 0.5 0.05 0.05 0.05 0.05 0.05 240 2 bal. 5 One 1.0 0.1 0.1 0.1 - - 245 3 bal. 8 2 1.5 0.3 0.2 0.1 0.05 0.05 265 4 bal. 10 3 2.0 0.5 0.05 0.2 0.1 - 270 5 bal. 15 4 2.5 1.0 0.05 0.1 0.1 0.1 280 6 bal. 10 0.5 210 7 bal. 5 0.1 0.5 0.5 0.1 0.1 240 8 bal. 0.2 0.8 0.8 200 ratio
School
ashes 9 bal. 0.2 - - - - - - 175 10 bal. 4 3.0 180 11 bal. 10 0.8 - - - - - - 190 12 bal. 10 2.9 1.5 - - - - - 195 13 bal. 10 3.5 2.5 - - - - - 205 14 bal. 10 4.5 3.0 - - - - - 210

As such, when the hardness was increased, a representative winding test was conducted to investigate changes in adhesion and workability, and the results are summarized in Table 2. In the winding test, after winding the steel wire plated on the wire of the same diameter as the test piece eight times, the peeling or cracking occurred in the plated layer was examined. Inventive material with high hardness was found to be very good in cracking and peeling characteristics compared with the conventional comparative materials. Therefore, the fine process structure obtained from the inventive material is considered to contribute greatly to the improvement of adhesion and workability of the plating layer as well as the hardness characteristic.

<Table 2>

Alloy plating component (wt.%) Winding test sample
number Zn Al Mg Si MM Sc Y Zr Hf Er crack Peeling foot
persons
ashes One bal. 3 0.5 0.5 0.05 0.05 0.05 0.05 0.05 ◎ ◎ 2 bal. 5 One 1.0 0.1 0.1 0.1 - - ◎ ◎ 3 bal. 8 2 1.5 0.3 0.2 0.1 0.05 0.05 ◎ ◎ 4 bal. 10 3 2.0 0.5 0.05 0.2 0.1 - ◎ ◎ 5 bal. 15 4 2.5 1.0 0.05 0.1 0.1 0.1 ◎ ◎ 6 bal. 10 0.5 ◎ ◎ 7 bal. 5 0.1 0.5 0.5 0.1 0.1 ◎ ◎ 8 bal. 0.2 0.8 0.8 ◎ ◎ ratio
School
ashes 9 bal. 0.2 - - - - - - ○ ○ 10 bal. 4 3.0 ○ ○ 11 bal. 10 0.8 - - - - - - ○ ○ 12 bal. 10 2.9 1.5 - - - - - ○ ○ 13 bal. 10 3.5 2.5 - - - - - x x 14 bal. 10 4.5 3.0 - - - - - x x

(◎: very good, ○: excellent, x: poor)

   Therefore, the alloy plating component of the present invention was greatly effective not only in the strength of the plating layer itself but also in improving adhesion and workability.

Claims (4)

One or two of the nucleation promoting elements Sc, Y, Zr, Hf and Er are added to a molten plating solution composed of any one of molten zinc, a molten zinc-aluminum alloy, and a molten Zn-Al-Mg-Si-based alloy. The hot-dip iron wire, characterized in that the composite structure is added to promote the nucleation at the time of forming the plating layer to form uniformly formed fine grains of isotropic crystals.  The nucleation-promoting element according to claim 1, which contains Sc: 0.01-1.0, Y: 0.01-1.0, Zr: 0.01-1.0, Hf: 0.01-1.0, Er: 0.01-1.0 by weight ratio. Hot-dip iron wire. One or two of the nucleation promoting elements Sc, Y, Zr, Hf and Er are added to a molten plating solution composed of any one of molten zinc, a molten zinc-aluminum alloy, and a molten Zn-Al-Mg-Si-based alloy. The hot dip galvanized steel wire, characterized in that the composite structure is added to promote the nucleation at the time of forming the plating layer to form uniformly formed fine crystal grains of isotropic crystals.   4. The nucleation promoting element according to claim 3, wherein Sc: 0.01-1.0, Y: 0.01-1.0, Zr: 0.01-1.0, Hf: 0.01-1.0, Er: 0.01-1.0 by weight ratio is contained. Hot dip galvanized steel wire.