JPS59166664A - Heat resistant zinc alloy plated product - Google Patents

Abstract

PURPOSE:To contrive to enhance heat resistance and plated surface state, by applying a molten plating bath comprising an alloy containing Al, Ca and Zn in a predetermined ratio to the surface of a ferrous metal. CONSTITUTION:A Zn-alloy comprising 0.2-14% Al, 0.005-0.5% Ca and the remainder of Zn is melted to form a molten plating bath in which a ferrous metal is, in turn, immersed to apply the molten plating to the surface thereof. The obtained Zn-alloy plated product is excellent in heat resistance and plated surface state.

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 resistance has been required, and heat-resistant steel core aluminum stranded wire (hereinafter referred to as AC8R) has been used for applications 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. ) or used. The iron-based metal used for such heat-resistant AC5R is usually AC5
AJ coated galvanized steel wire is used.

However, although AJ coating has excellent corrosion resistance and heat resistance, it is expensive, and zinc plating is inferior to Al coating, but it improves the corrosion resistance as AC3R and is also cheap. On the other hand, due to intense diffusion, Kirkendall bonds are formed at the Zn-Fe alloy layer interface, causing interfacial delamination (it cannot be widely used in the core material of Japanese gold).

Has it been found that the heat resistance of Zn plating can be improved by adding ``Aj?'' to Zn, or by suppressing the growth of the Zn-Fe alloy layer at the interface? Because of the severe oxidation of AJ in the plating bath, the surface condition of the plating was poor and there were problems with non-adherence.

(Disclosure of the Invention) The present invention has been made to solve the above-mentioned problems, and has excellent heat resistance and good surface condition of zinc alloy plating.
The purpose is to provide zinc alloy plated iron metal products that do not have any defects.

The present invention provides Aj? 0.2-14%, C
This is a heat-resistant zinc alloy plated product characterized by being formed by hot dipping a Zn alloy containing aO.

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. Fe-N, which has a small coefficient of thermal expansion, has been attracting particular attention recently.
I-based alloys can also be used. As this alloy, N
There are alloys containing 135-42%. The shape of the product may be a line, strip, square plate, tube, or any other shape.

In general, iron-based metals and Zn are heated during or after hot-dip plating of Zn to form three types of compound layers (γ (gamma), δ (telk), and ζ (zeta)).

Such a Fe-Zn compound causes a deterioration in toughness and, for example, a decrease in surface vibration fatigue strength when heated at 300° C. for 100 hours. Furthermore, when heated at 300° C. for 100 hours, the torsion value decreased significantly, and in extreme cases, it was observed that peeling occurred at the interface of the grown alloy layer.

In order to suppress the growth of this compound layer, in the present invention, Zn
Add K kl O, 2-14%. ZnKAj? 0
．． The reason for adding 2 to 14% is that F
Zn-Fe preferentially forms the alloy layer of e2AJ5 and causes peeling during plating or heating during use.
This is to suppress the growth of the alloy layer and improve heat resistance.

When the AJ amount is less than 02%, the Fe2Al5 layer required for 1d1 is not formed, and a Fe-Zn alloy layer is formed during hot-dip plating, and the plating layer is peeled off due to the growth of the alloy layer during the unwinding test after high-temperature heating. - Is it effective for improving heat resistance and sluggishness? (If the amount of Aj exceeds 14%, not only will the effect of suppressing the alloy layer become saturated, but the viscosity of the molten Zn alloy will also increase. However, the oxidation of AJ will be severe and the surface condition of the plating will deteriorate, making it difficult to adjust the bath composition.

In addition, in the present invention, CaO, 005 to 05% is added to the Zn alloy.
The reason for adding is to suppress the oxidation of AJ during hot-dip plating, improve fluidity and wettability, improve the surface condition of the plating, and prevent defects.If it is less than 0.005%, Addition of more than 0.5% without this effect saturates the effect and only increases the cost.

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 treatment of one steel wire may be a degreasing-pickling-Franks treatment or a degreasing-reduction method. P for degreasing
Degreasing using b-bath, degreasing using electrolysis, etc., and pickling using HCJ, electrolytic pickling using H2SO4, etc. can be used. ZnCl2, NH4C as flux
A mixed flux of 1 is used.

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

(Example) A 27 mmΦ steel wire was degreased with a Pb bath, pickled with HCgK, and subjected to a mixed flux treatment of Zn C12 and NH4Cl, and then hot-dip Zn alloy plating was performed using the plating bath composition shown in Table 1. The temperature of each plating bath was 30° C. above the liquidus line, the immersion time was 15 seconds, and carbon powder was used for the squeezed portion.

Table 1 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. .

From Table 1, it can be seen that all of Arashi 2 to Arashi 7 according to the present invention had no plating, had good surface conditions, and had excellent heat resistance.

On the other hand, %1 without adding Al and Ca. A#.

Low lV of Ca content! No. 18 causes plating peeling, poor heat resistance, non-adherence, and AJ amount exceeding 14%.
%11,1Vllll12 significantly deteriorates the surface condition of the plating, and 99%10 with a Ca content of less than 0005% is ineffective in preventing non-adhesion of the plating and improving the 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) Is it a Zn alloy that is hot-dipped on the surface of iron-based metal?
l? Since it contains 0.2 to 14%, F
An alloy layer of e2Al5 is formed preferentially and Fe-
Since the growth of the Zn alloy layer is suppressed, the heat resistance is significantly superior to conventional Zn plated products.

(D) Since the Zn alloy contains 0.005 to 0.5% of CaO, A/? suppresses the oxidation of
Fluidity and buildability are improved, so the surface condition of the plating is good and it does not stick.

34F

Claims (1)

[Claims] A heat-resistant zinc alloy plated product characterized by being formed by hot-dipping a Zn alloy containing impurities.