JPH02310349A - Non-rotating sink roll for molten metal plating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Industrial Application Field The present invention relates to a sink roll immersed in a molten metal bath.

(b) Conventional technology Hot-dip metal plating (typically hot-dip galvanizing) is as shown in Figure 5. A steel strip 3 is continuously immersed in a bathtub 2 of (typically zinc) 1, and the advancing direction of the steel strip 3 is reversed by a sink roll 4 provided in the bathtub 2 and guided out of the bathtub 2. The surface of the band is plated. The steel strip 3 is reduced annealed in an annealing furnace 5 before being introduced into the bath 2.

The sink roll 4 is normally not driven, but is rotated by the frictional force with the steel strip 3. In order to make it easier for the sink roll 4 to rotate, some rolls have grooves or holes on the roll surface so that molten metal can easily escape.

For example, in the bath 2 of the zinc bath, there are 300 microns, which are generated in the zinc bath by the reaction between the steel strip 3 and the molten zinc 1.
Micron-sized Fe-Zn alloy particles 6 (bottom dross) are deposited at the bottom of the bathtub 2 as shown in the figure due to the difference in specific gravity with the bath.

However, when the steel strip 3 begins to pass through the bath, the dross 6 tends to be rolled up due to the passage of the steel strip 3 and the stirring force caused by the rotation of the sink roll 4, depending on the passing speed. is sink roll 4 and steel strip 3
and adheres to the surface of the steel strip 3, forming surface defects called dross defects. The dross defects generated in this way not only caused deterioration in the appearance of the steel strip surface, but also caused deterioration in corrosion resistance as a result of assembling the pole battery.

A technique has been disclosed in which a plurality of rotors are provided spirally on the surface of a cylindrical body or a conical body to change the traveling direction of the steel strip (Japanese Utility Model Publication No. 60-7845, Japanese Patent Application Laid-Open No. 60-24214). However, these techniques do not prevent agitation of dross in the molten metal bath.

(c) Problems to be Solved by the Invention The problems to be solved by the present invention are to prevent stirring of dross generated in a bath during hot-dip metal plating, and to obtain plated products without dross defects. The goal is to provide think rolls.

(d) Means for Solving the Problems The non-rotating sink roll for hot-dip metal plating of the present invention continuously passes a steel strip through a molten metal bath, and the sink roll reverses the traveling direction of the steel strip while metallizing the molten metal. In a plating facility, the sink roll is fixed in a bath, and a plurality of small-diameter rotating bodies are rotatably embedded at a predetermined interval within a predetermined range of the sink roll surface.
The above issues have been resolved.

Stainless steel is used for the sink roll surface support part of the rotating body,
Preferably, one of ultra-low carbon steel, ceramics, molybdenum alloy, and other metal spray materials is used.

The rotating body is one of a cylindrical shape, a spherical shape, and a rotating oval shape.

(e) Function: As a result of comparing the amount of bottom dross rolled up by the passage of the steel strip through the molten metal bath and the amount of bottom dross rolled up only by the rotation of the sink roll, it was found that the amount of bottom dross rolled up by the rotation of the sink roll alone was It has been found that when the width W is narrow (W<L), the ratio of the amount of bottom dross rolled up only by the rotation of the sink roll is high.

Based on this knowledge, the sink roll main body has a non-rotating structure, and for threading the steel strip, multiple cylindrical or spherical rotating bodies are arranged on the surface of the sink roll main body to rotate in the advancing direction of the steel strip. , the steel strip is turned over in the bath without damaging the steel strip by its rotation.

On the cylindrical surface of the sink roll, a rotating band that rotates in the direction of travel of the steel strip is arranged, and the zero-rotating body that rotates in synchronization with the speed of the steel strip is rotatably held by sink roll bearings. , due to the friction force between the steel strip and the steel strip,
Rotate.

In a molten metal bath, the material rapidly erodes due to the reaction with the molten metal, so the rotating body and its support are made of stainless steel, ultra-low carbon steel, and ceramics that have excellent resistance to molten metal wL (zinc) corrosion. (tungsten carbide, silicon nitride, etc.), molybdenum alloy, or a material sprayed with it.

The shape of the rotating body may be cylindrical, spherical, or partially chamfered if necessary.

(F) Embodiment An embodiment of the sink roll 40 of the present invention will be described with reference to FIGS. 1 to 4.

The sink roll 40 of the present invention, as described above with reference to FIG. 5, is immersed in a molten metal bath to reverse the direction of travel of the steel strip in the bath. The sink roll 40 is fixed within the bathtub 2 (FIG. 5).

A small diameter rotating body 4 is placed within a predetermined range on the surface of the sink roll 40.
1 are rotatably embedded in a plurality of locations at predetermined intervals.

As shown in FIG. 3, the rotating body 41 can have a cylindrical shape (A), a spherical shape (B), a rotating oval shape (C), or a chamfered cylindrical shape (D).

The sink roll surface support portion 42 of the rotating body 41 is made of stainless steel, ultra-low carbon steel, ceramics, molybdenum alloy, or other metal sprayed materials.

A specific example of the sink roll 40 of the present invention will be described.

<Specific Example 1> As shown in FIGS. 1 and 2, a rotating body 41 and a shaft of the rotating body 41 integrally molded with silicon nitride are placed on a sink roll 40 with a steel strip 3 as shown in the figure. It was placed in the contact area and installed in a continuous hot-dip galvanized bathtub 2 (Fig. 5) with a width of 6 shaku, and the occurrence of dross defects was investigated before and after installation.

The compared conventional sink roll 4 has a diameter of 30 mm on the roll surface.
It is a hollow roll with many III+ holes.

Regarding the occurrence of dross defects, the plated steel strip 3 was cut out at the exit side of the line, and the number of dross defects adhered per 1 d was visually counted. The results are shown in Table 1.

As shown in Table 1, although the effect differs depending on the product width, the generation of dross defects was significantly suppressed by the generation of sink rolls of the present invention.

<Specific Example 2> A water model test device capable of simulating the bathtub area of a hot-dip galvanizing line was manufactured, a sink roll 4 having a similar shape to that in Fig. 1 was installed, and a conventional sink roll and a sink roll of the present invention were installed. We compared the differences between The test device, as shown in FIG. 6, is a device that can endlessly rotate a steel strip 3 having a width of 300 circles. By moving the motors 7 and 8, it was possible to compare the conventional sink roll 4 and the sink roll 40 of the present invention. Particles with a specific gravity of 1.1 were deposited on the bottom as bottom dross, and a certain amount of the rolled up bottom dross was sucked together with water, and the weight of the filter was measured to measure the amount of bottom dross rolled up. Second
The results are summarized in the table 0 Sheet threading speed 1001111
Under certain conditions, the volume of the water tank is 2 m3, and the amount of bottom dross input is 100 m3, the amount of bottom dross lifted up by the present invention is 17 m3.
Reduced to 10.

Table 2 (G) Effect Since the sink roll of the present invention is fixed in the bathtub so as not to rotate, it does not stir up dross in the bath and prevents dross from entering between the sink roll surface and the steel strip. Even if there is dross, the rotating body can prevent the dross from getting caught.

[Brief Description of the Drawings] Fig. 1 is a perspective view of the sink roll of the present invention, and Fig. 2 is a perspective view of the sink roll of the present invention.
The figure shows a front view, and FIG. 3 is a side view of the rotating body. FIG. 4 is a perspective view of the sink roll of the present invention in use, and FIG. 5 is a schematic explanatory diagram of hot-dip metal plating equipment. FIG. 6 is an explanatory diagram of the test device. 40 Herring roll 41: Rotating body 42: Supporting part Patent applicant: Sumitomo Metal Industries, Ltd.

Claims (1)

[Claims] 1. In an equipment that performs molten metal plating by passing a steel strip continuously through a molten metal bath and reversing the traveling direction of the steel strip by a sink roll, the sink roll is fixed in the bath. A non-rotating sink roll for molten metal plating, characterized in that a plurality of small-diameter rotating bodies are rotatably embedded within a predetermined range of the sink roll surface at predetermined intervals. 2. The sink roll according to claim 1, wherein one of stainless steel, ultra-low carbon steel, ceramics, molybdenum alloy, and other metal sprayed materials is used for the sink roll surface support portion of the rotating body. 3. The sink roll according to claim 1, wherein the rotating body is one of a cylindrical shape, a spherical shape, and a rotating oval shape.