JPH02138452A - Method and device for hot-dipping wire - Google Patents

Abstract

PURPOSE:To form a high-quality plating layer with reduced unevenness in thickness and inclusion of impurities on a wire by passing the wire through a molten metal held at a high temp., vertically pulling up the wire, and passing the wire through a molten metal having a low content of impurities with the surface covered with a nonoxidizing atmosphere via a positioning die. CONSTITUTION:The wire 1 to be hot-dipped is passed through the first molten metal 2 in the first molten metal tank 3 held at a temp. about 100 to 350 deg.C higher than the m.p. via a turn roll 5, and then vertically pulled up. The wire 1 is then passed through the second molten metal 8 in the second molten metal tank 6 having a low content of impurities via the positioning die 7, and taken out through a nonoxidizing atmosphere 4. By this method, the unevenness in the thickness of the plating layer is reduced, the inclusion of impurities in the plating layer is decreased, and a high-quality plated wire is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a wire hot-dip plating method and an apparatus therefor, which can obtain a high-quality plated wire with less uneven thickness of the plated layer and no contamination of impurities. be.

[Prior Art and its Problems] 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 treatment.

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

In the normal hot-dip plating method, copper wire with a diameter of 0.4 to 0.9 mm is plated with tin or solder to a thickness of several to several tens of mm, but these plated metals are relatively thin. Since it is expensive, it is desired 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 with the metal 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.

[Problems to be Solved by the Invention] As a result of studying the above-mentioned problems, the present invention provides a high quality Menki wire with less unevenness in plating thickness and no impurities in the plating layer without using a drawing die. We have developed a method and device for plating wire rods.

[Means and effects for solving the problems] The present invention involves passing a wire rod through a first molten metal held at a temperature of 100°C or more higher than the melting point via a turn roll, and then passing it through a positioning die into a second molten metal with fewer impurities. Claim 1 provides a method for melt coating a wire rod, characterized in that plating is carried out by pulling the wire vertically through the molten metal and passing it through a non-oxidizing atmosphere on the outlet side, the first melt coating being maintained at a temperature of 100° C. or more above the melting point. A turn roll or a turn shaft is provided in the metal tank, and a second molten metal tank having a positioning die at the bottom is provided at a location where the wire is vertically pulled up via the turn roll, and a second molten metal tank is provided in the second molten metal tank. Claim 2 provides a wire rod hot-dip plating apparatus characterized in that a device is provided for supplying a new metal or a molten metal obtained by filtering the first molten metal, and the second molten metal surface is shielded in a non-oxidizing atmosphere. , also the first
A claim characterized in that, when filtering the molten metal and supplying it to the second molten metal tank, the molten metal is cooled to a temperature equal to or lower than the melting point of the first molten metal by 50°C or less. Claim 3 provides the wire rod hot-dip plating apparatus according to claim 2.

Specific examples of the present invention will be described below.

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 or solder, (3) is the first molten metal tank, (4) is a gas shield such as Ar or N to maintain a non-oxidizing atmosphere on the line exit side, (5) is ) is a turn roll or shaft installed in the molten metal, [6] is a second molten metal tank having a positioning die (7) at a point vertically pulled up from the turn roll, and (8) is a second molten metal tank. It is molten metal, (9) is a wire rod for supplying new plating metal, and OI is its introduction pipe.

Note that instead of supplying the above-mentioned new plating metal, the first molten metal may be filtered and supplied. In this case, a device is provided to cool and supply the molten metal to a temperature below the melting point of the first molten metal plus 50°C.

Accordingly, the method of the present invention uses the above-mentioned apparatus to pass through the first molten metal (2) held at a temperature of 100° C. or more higher than the melting point via the turn roll (5), and then passes through the positioning die (7). ) through which the second one has fewer impurities? 'JI
Plating is performed by vertically pulling up the A metal (8) and passing through the non-oxidizing atmosphere (4) on the exit side.

In the present invention, the temperature of the first molten metal is 10° below the melting point.
It is desirable to set the temperature to 0° C. or higher; otherwise, the molten metal will not have appropriate physical properties such as viscosity and surface tension, so uniform plating will not be possible and the surface will be uneven.

However, if the temperature is too high, oxidation will proceed, so the temperature is preferably 350° C. or lower than the melting point.

Further, the second molten metal is used to constantly supply new plating metal in order to maintain a state with less Cu-3n intermetallic compounds, and the molten metal overflows and transfers to the first molten metal tank. Instead of supplying new plating metal, the first molten metal may be filtered and supplied; in this case,
i+ by cooling to below the melting point of the first molten metal plus 50°C
15, the Cu-3n intermetallic compound in the bath solidifies and becomes easier to remove. After filtration, the temperature may be raised and then supplied to the second tank. The temperature of the molten metal in the second tank is preferably about the same as the temperature in the first tank, and therefore it is better to keep the temperature of the first tank slightly higher and stable.

The wire rod to be supplied may be a wire rod such as a copper wire coated with flux and then introduced into the molten metal, or a wire rod that has been subjected to normal fusion coating. 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. The plating thickness is determined by the diameter of the wire, temperature, immersion length, bath temperature, ridge, etc., but the conditions for achieving the desired thickness may be determined for each piece of equipment in advance.

Since the present invention does not use a drawing die, uneven thickness due to misalignment of the relative positions of the wire rod and the drawing jig can be prevented. Further, residues such as molten metal oxides and Cu-3n intermetallic compounds adhering to the wire in the first molten metal tank are removed by a positioning die provided at the bottom of the second molten metal tank, and
In the bath, a bath containing few Cu-3n intermetallic compounds is used, and the environment is non-oxidizing, so that oxides are generated very little. Therefore, the incorporation of dregs into the wire plating layer is prevented, and a high-quality coated wire without uneven thickness of the plating layer and no impurities 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 mmφ was coated with hydrochloric acid-zinc chloride flux by a conventional method, and then
The eutectic solder is introduced into the first molten metal (2) held at 0°C, changed direction vertically via a turn roll (5), and placed at the bottom of the second molten metal tank (6). The second molten metal (8) with few impurities kept at 335°C was brought into contact with the second molten metal (8) with few impurities through the positioning die (7), and the scene exit was set at 250°C.
Solder plated copper wire was produced by pulling upward through a non-oxidizing shield (4) sealed with N2 at 0.degree.

The linear speed at this time was 20 m/min. In addition, a new eutectic solder Menki metal (9) is introduced into the second molten metal tank through pipe 00.
) was constantly supplied.

Example 2 As the second molten metal, the first molten metal has a melting point plus 4
A solder-plated copper wire was produced in the same manner as in Example 1, except that the solution was cooled to 0° C., filtered, and then heated to 335° C. before being supplied.

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

Comparative Example 2 A solder plated wire was manufactured under the same conditions as in Example 1, except that a drawing die was used for the soldering scene at the wire exit.

Comparative Example 3 A solder plated wire was manufactured under the same conditions as in Example 1 except that the temperature of the first molten metal was 240°C and the temperature of the second molten metal was 235°C.

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 coated copper wire was heat treated at a temperature of 170°C for 48 hours, and then flux (rosin/IPA = 25/75) was applied to the surface and immersed in a 235°C eutectic solder bath for 5 seconds. The solder wet area was determined. These results are shown in Table 1.

Table 1 As is clear from Table 1, the hot-dip plated wire according to the present invention has a small thickness unevenness in the plated layer, does not incorporate impurities, and is easy to solder after heat treatment despite the thin plating thickness. Recognized as having excellent sexual qualities.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to significantly reduce the thickness unevenness of the plated layer, and to manufacture a high-quality plated wire with less incorporation of impurities into the plated layer. It has a remarkable industrial effect.

[Brief explanation of the drawing]

FIG. 1 is a side view of a melting coating apparatus used in an embodiment of the present invention. 1... Wire rod, 2... First molten metal, 3...
First molten metal tank, 4... Non-oxidizing atmosphere shield, 5... Turn roll, 6... Second molten metal tank, 7... Positioning die, 8... Second melting Metal, 9...Plated metal, 10...Introduction pipe.

Claims (3)

[Claims] (1) The first wire is held at a temperature of 100°C or more above its melting point.
The wire rod is passed through a turn roll, then vertically pulled up through a positioning die into a second molten metal with few impurities, and passed through a non-oxidizing atmosphere on the exit side to perform plating. hot-dip plating method. (2) A turn roll or a turn shaft is provided in the first molten metal tank maintained at a temperature of 100°C or more higher than the melting point, and a second molten metal tank having a positioning die at the bottom is provided at the point where the wire is vertically pulled up via the turn roll. A molten metal tank is provided, and a device for supplying new metal or molten metal obtained by filtering the first molten metal to the second molten metal tank is provided, and the second molten metal surface is shielded with a non-oxidizing atmosphere. A hot-dip plating device for wire rods, which is characterized by: (3) When filtering the first molten metal and supplying it to the second molten metal tank, the molten metal temperature is set to the melting point of the first molten metal plus 50
3. The hot-dip plating apparatus for wire according to claim 2, further comprising an apparatus for supplying the wire after cooling it to a temperature of .degree. C. or lower.