JPS59166666A - Product coated with heat resistant zinc alloy - Google Patents

Abstract

PURPOSE:To contrive to improve heat resistance and the condition of a coated surface, by applying the hot-dip coating of an alloy containing the predetermined amounts of Al, Ti, B and Zn onto the surface of a ferrous-group metal. CONSTITUTION:A Zn alloy comprising 0.2-14% Al, 0.01-0.3% Ti, 0.002-0.1% B and the balance Zn is melted. By dipping a ferrous-group metal in this hot- dip coating bath, a hot-dip coating layer is applied onto its surface. The obtd. product coated with the Zn alloy is excellent in heat resistance and condition of the coated surface.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a product in which the surface of an iron-based metal is hot-dipped with a zinc alloy, and particularly to a zinc alloy plated product with excellent heat resistance.

(Background Art) Conventionally, Zn plating has been widely adopted for improving corrosion resistance. In recent years, heat-resistant steel-core aluminum stranded wire (hereinafter referred to as AC8R) has been used for applications that require heat resistance, such as increasing power transmission capacity and improving the reliability of power systems by operating one circuit in the event of an accident during two-line operation. ) is used. The iron-based metal wire used for such heat-resistant AC5R is usually AC
A for 3R steel wire! ? It is used coated and galvanized.

But A/? Although the coating has excellent corrosion resistance and heat resistance, it is expensive, and zinc plating, although inferior to AJ coating, improves the corrosion resistance of AC5R and is cheap, but it prevents Zn from turning to the Fe side due to heating. Due to diffusion,
Kargundor voids are formed at the interface of the Zn-Fe alloy layer, causing interfacial peeling (Journal of the Japan Society of Wood and Metals, 39).
, 1975. (See pages 903 to 908), the heat resistance is poor when used at a high temperature of about 260℃, and the heat resistance is AC3R 6.
It cannot be widely used for kidnapping.

To improve the heat resistance of Zn plating, add Al into Zn? 01
Has it been found that A/F in the hot-dip Zn plating bath has the effect of suppressing the growth of the Zn-Fe alloy layer at the interface? Because of the severe oxidation of the plating, the surface condition of the plating was poor and there was a problem of non-adherence.

(Disclosure of the Invention) The present invention has been made to solve the problems mentioned in -11. Zinc alloy plating has excellent heat resistance, has a good surface condition, and is free from adhesion. We aim to provide products.

In the present invention, Aj'0.2 to 14%,
This is a heat-resistant zinc alloy plated product characterized by hot-dipping a Zn alloy containing 1 to 0.3% of TiO, O, 0.02 to 0.1% of Bo, and the balance being Zn and unavoidable impurities.

In the present invention, the ferrous metal used as the base material is iron, steel, special steel to which other alloying elements are added, or iron alloy. In particular, F e with a small coefficient of thermal expansion has been attracting attention recently.
-=Ni-based alloys and the like can also be used. This alloy includes an alloy containing 35 to 42% Ni. The shape of the product may be a line, strip, Tefumi plate, tube, or any other shape.

In general, iron-based metals and Zn are heated during or after hot-dip plating of Zn to generate three types of compound layers (r (gamma), δ (delta), and ζ (zeta)). In addition, due to the Fe-Zn compound, there were cases in which peeling occurred at the interface of the alloy layer, which had poor toughness.

In order to suppress the growth of this compound layer, in the present invention, Zn
Add K kl O, 2-14%. ZnKAlo,
The reason for adding 2 to 14% is that F
By preferentially forming an alloy layer of e2A/'5, the growth of the Zn-Fe alloy layer, which is resistant to peeling during plating or heating during use, is suppressed, and the athermal properties are improved. If the AJ amount is less than 0.2%, the required F
Fe-Zn is not formed during hot-dip plating without forming e2Aj'5 layer.
An alloy layer is formed, and the plating layer peels off due to the growth of the alloy layer during a winding and unwinding test after high-temperature heating, which is ineffective in improving heat resistance, and when the AJ amount exceeds 14%, the alloy layer Not only does the suppressing effect become saturated, but the viscosity of the molten Zn alloy increases, and even if Ti and B are added, Al is oxidized violently, the surface condition of the plating deteriorates, and it becomes difficult to adjust the bath composition.

In addition, in the present invention, Tl, B L:Df to Zn alloy
By these combined additions, Zn-Aj? The crystal grains of the alloy are refined and a plated product with an extremely good appearance can be obtained. Furthermore, as an effect of grain refinement, the occurrence of unattached portions can be suppressed. These effects are due to the fact that the fluidity of areas with high Aj' concentrations that occur at the plating inlet and constriction areas is suppressed by the addition of Ti and B, preventing them from entering the bath together with the paulownia to be plated, and preventing them from being carried away. Because there is no
It is thought that this is because the Zn alloy bath and the material to be plated can react sufficiently during the plating process, and the constriction effect by the plate surface can be sufficiently exerted in the constriction area.

Also, it is difficult to add Ti and H individually, but Aj?
-5%T1, AJ-5%B, Al4-5%Ti-1%
It can be easily added by using a mother alloy of B or the like. Since it can be added in the form of a master alloy at the same time as AJ, it also has the advantage of easy composition adjustment. Is it better to heat the bathtub itself to keep it warm?AJ
Preferable from the viewpoint of component adjustment.

The reason why the amount of Ti is defined as 0.01 to 03% and the amount of B is 0002 to 01% is that if Ti is less than 01% and Bo is less than 002%, the addition has no effect, and if Ti exceeds 0.3% and 801%, respectively. As the effect saturates, the fluidity of the plating bath decreases, and it becomes necessary to increase the temperature of the plating bath.

Next, the method for manufacturing a zinc alloy plated product of the present invention will be explained using a zinc alloy plated steel wire as an example, but the present invention is not limited thereto.

First, the pretreatment of the steel wire may be a degreasing-pickling-7 lasox treatment or a degreasing-reduction method. For degreasing, degreasing by Pb bath, degreasing by electrolysis, etc., and for pickling, HC
Pickling with J, electrolytic pickling with H2SO4, etc. can be used. A mixed flux of Zn C12 and NH4C1 is used as the flux.

The temperature of the hot-dip plating bath is suitably within the range of 10 to 50°C above the liquidus line, and is not particularly limited, or within the range of 30°C above the liquidus line.
There is little loss in strength of the steel wire and little corrosion of the plating pot.

(Example) A steel wire with a diameter of 3.0 mm was subjected to destrengthening in a PB bath, pickling in HC7, ZnCl2. After performing a mixed flux treatment of NH4C1, hot-dip Zn alloy plating was performed using the plating bath composition shown in Table 1. For each plating, the temperature was 6 degrees above the liquid phase and 30 degrees Celsius, the immersion time was 15 seconds, and carbon powder was used for squeezing.

Table IK shows the presence or absence of plating on the obtained zinc alloy-plated steel wire, the surface condition, and the presence or absence of plating peeling in the winding and unwinding test at its own diameter after heating at 260° C. for 1000 hours.

Table 1 From Table 1, it can be seen that all of the samples from %8 to 13 according to the present invention had no unplated coating, had good surface conditions, and had excellent heat resistance.

On the other hand, in Table 1, which does not contain Al, Ti, and B. A/Low quantity 3. N114 has poor heat resistance and low Ti and B content (29%)3. Depth 5 has a poor surface condition, and Depth 6 has a large amount of Al.
．． Recess 7 is also in poor surface condition.

(Effects of the Invention) The heat-resistant zinc alloy plated product of the present invention configured as described above has the following effects.

(B) The Zn alloy hot-dipped on the surface of iron-based metal is A.
Since it contains 0.2 to 14% of F during plating,
It preferentially forms an alloy layer of e2A15 and suppresses the growth of the Fe-Zn alloy layer, which causes peeling of the plating, even if it is heated during plating or during use. It has significantly better heat resistance than plated products.

(o) Zn alloy has Ti 0.01-0.3%, B
Since the Zn alloy contains 0.002 to 0.1%, the combined addition of Ti and H makes the crystal grains of the Zn alloy finer as described above, resulting in a plated product with an extremely good appearance. Since it is possible to suppress the generation of
Compared to midstream additives, the plating surface condition is better and the final
It's not 4.

Claims (1)

[Claims] (1) AAo, 2-14%, Ti0 on the surface of iron-based metal
A heat-resistant zinc alloy plated product characterized by being formed by hot-dipping a Zn alloy containing 901-03, Bo, 002-0.1%, and the remainder being Zn and inevitable impurities.