JPH02129355A - Hot dipping method for wire - Google Patents

Abstract

PURPOSE:To obtain a hot dipped wire having almost uniform plating thickness without using a squeezing die by passing a wire passed through a turn roll in molten metal through plural centered positioning dies, and then vertically raising the wire as it is. CONSTITUTION:The wire 1 is introduced into the molten metal 2 kept at a temp. >=100 deg.C higher than the m.p., deflected by the turn roll 5 in the vertical direction, and passed through plural positioning dies 6. The wire 1 passed through the dies 6 is vertically pulled out from the molten metal 2 through the shield 4 of a nonoxidizing atmosphere, and plated. In addition, plural dies 6 are used, and their centers are aligned with the position of the roll 5 in the vertical direction. Since a squeezing die is not used in this method, the nonuniformity in the thickness due to the deviation in the relative positions between the wire and squeezing jig can be prevented. In addition, the infiltration of impurities into the plating layer is reduced, and a high-quality plated wire is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for hot-dip plating wire rods, which provides a high-quality plated wire with less uneven thickness and no contamination of impurities.

[Conventional technology and its issues]

BACKGROUND OF THE INVENTION Tin or solder (tin-lead alloy) plated copper wire is often used for lead wires and wiring of electronic and electrical equipment to facilitate soldering and terminal processing.

Hot-dip plating is typically used to manufacture tin or solder-plated copper wire. In this method, the wire is passed through a molten coating bath of tin or solder, passed through a drawing die to remove excess plated metal, and then cooled and solidified in the atmosphere.

In the normal melt coating method, tin or solder is coated on a copper wire with a diameter of about 0.4 to 0.9 am to a thickness of several to several liters, but these coating metals are relatively thin. Due to the low cost, it is desirable to make the plating thickness as thin as possible. However, the plating layer is often formed eccentrically with respect to the wire due to the vibration of the wire, which causes the relative position of the wire and the drawing die to be distorted. Since the alloy is exposed and soldering significantly deteriorates the characteristics, it has been difficult to reduce the plating thickness beyond a certain level.

Further, impurities such as oxides and dregs tend to float on the surface of the molten metal, and these impurities adhere to the surface of the wire and are incorporated into the plating layer, resulting in the problem of deteriorating the soldering properties. Furthermore, the above impurities accumulate in the drawing die, causing problems such as wire breakage, uneven plating thickness, and surface scratches.

[Problem to be solved by the invention]

As a result of studies on the above-mentioned problems, the present invention has developed a wire plating method that can produce high-quality plated wire with less uneven plating thickness and no impurities in the plating layer without using drawing dies. It is.

(Means and effects for solving the problems) The present invention provides a hot-dip plating method in which a wire is passed through molten metal for plating, in which the molten metal is heated to a temperature of 100°C or more above its melting point, and the molten metal is rotated in the molten metal. After passing the roll,
This hot-dip plating method for wire rods is characterized by passing the wire through a plurality of aligned positioning dies, standing up the wire vertically without using a jig to squeeze the molten metal, and passing through a non-oxidizing atmosphere.

Specific examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view schematically showing an apparatus for hot-dip plating according to the present invention, and (1) shows a wire rod coated with flux or a wire rod subjected to hot-dip plating.

(2) is molten metal such as tin and solder, (3) is a coating tank,
(4) is Ar for maintaining a non-oxidizing atmosphere on the line port side;
N! (5) is a turn roll or shaft installed in the molten metal, (6) is two or more positioning dies installed in the molten metal, and the core of the turn roll and each die is Align vertically.

Then, the wire (1) is introduced into the molten metal (2), the direction is changed vertically by the turn roll (5), and the wire rod (1) is passed through the positioning die (6) to be separated from the molten metal (2) by the non-oxidizing atmosphere shield ( 4) The inside is pulled out in the vertical direction to perform the menki.

It is necessary to use a plurality of the above-mentioned positioning dies and to make sure that the positions of the respective cores and turn rolls are aligned in the vertical direction. Further, the wire rod to be supplied may be a wire rod such as a copper wire coated with flux and introduced into the molten metal, or a wire rod subjected to ordinary hot-dip plating may be introduced. In this case, it is preferable not to apply flux, since the generation of molten metal scum is reduced, but it is also possible to apply flux. Therefore, it is desirable that the temperature of the molten metal be at least 100°C higher than the melting point.If the temperature is not high, the appropriate physical properties such as viscosity and surface tension of the melting point metal cannot be obtained, so uniform plating cannot be achieved and the surface becomes rough. It becomes uneven. However, if the temperature is too high, oxidation of the molten metal will progress, so it is preferable to keep the temperature at 350°C higher than the melting point.

The plating thickness also depends on the wire diameter, temperature, wire speed, immersion length, bath temperature,
Although it is determined by the type of bath, etc., it is sufficient to find the conditions for achieving the desired thickness in advance for each piece of equipment.

In this way, the present invention does not use drawing dies, so it is possible to prevent uneven thickness due to misalignment of the relative positions of the wire rod and the drawing jig, and the plurality of positioning dies suppress the vibration of the wire coming out of the scene and solidify the wire. In addition to preventing uneven thickness that occurs during
n compounds, etc.) can be removed, eliminating the incorporation of scum into the wire plating layer, and creating a non-oxidizing atmosphere on the molten metal outlet side. Since no tate oxide is generated and incorporated into the wire plating layer, and the wire is cooled and solidified in this atmosphere, a beautiful plated wire can be obtained.

〔Example] An embodiment of the present invention will be described below.

Example 1 A copper wire with a wire diameter of 0.58 waφ was coated with hydrochloric acid to zinc chloride flux by a conventional method, and then placed in a eutectic solder bath (2) maintained at 350°C in the plating equipment shown in Fig. 1. The solder bath is then turned vertically through the turn roll (5), and two positioning dies (6) (aligned vertically with the line on the turn roll) are passed through the solder bath. A solder-plated copper wire was produced by passing the wire upward through a non-oxidizing shield sealed with N2 gas whose outlet was heated to 250°C. Note that the linear speed was 18 m/min.

Comparative Example 1 A copper wire with a wire diameter of 0.58 mmφ was coated with a hydrochloric acid to zinc chloride flux by a conventional method, and then introduced into a eutectic solder bath maintained at 270°C, passed through a turn roll, and then placed in the aperture. A solder-plated wire was produced by passing it through the die and pulling it upward. The line speed was 40 m/min.

Comparative Example 2 Same as Example 1 except that a drawing die was used for the soldering part of the closing port.
It was plated under the same conditions as .

Comparative Example 3 Plating was carried out under the same conditions as in Example 1, except that no alignment die was used.

For each solder-plated copper wire produced as described above, the cross section was observed under a microscope to determine the degree of uneven thickness of the plating layer, and the average plating thickness was determined using the Cole method. The appearance was also visually observed. Furthermore, each solder-plated copper wire was heat-treated at a temperature of 170°C for 48 hours, and then coated with fluffx (rosin/I PA-25/75) on the surface and heated at 235'C.
The solder wetting area was determined by immersing the sample in a eutectic solder bath for 5 seconds. These results are shown in Table 1.

As is clear from Table 1, the hot-dip plated wire according to the present invention has a small thickness deviation in the plated layer, does not incorporate impurities,
Although the plating layer is thin, it is recognized that the soldering properties after heat treatment are excellent.

(Effects of the Invention) As explained above, according to the present invention, it is possible to significantly reduce the degree of uneven thickness of the plated layer, and to produce a high-quality plated wire with less incorporation of impurities into the plated layer. It can produce significant industrial effects.

[Brief explanation of drawings]

FIG. 1 is a side view of a hot-dip plating apparatus used in one embodiment of the present invention. ■... Wire rod, 2... Molten metal, 3... Plating tank, 4... Non-oxidizing atmosphere shield, 5... Turn roll, 6... Positioning die.

Claims (1)

[Claims] In a hot-dip plating method in which a wire is plated by passing it through molten metal, the molten metal is heated to a temperature of 100°C or more above the melting point, and after passing through a turn roll in the molten metal, a plurality of aligned positioning dies are used. A method for hot-dipping a wire rod, which is characterized by vertically standing up the wire rod without using a jig to squeeze the molten metal, and passing it through a non-oxidizing atmosphere.