JPS589963A - Production of steel plate applied with metallic plating on one side - Google Patents

Abstract

PURPOSE:To obtain a one side plated steel plate of uniform quality at a low cost with a simple device by bringing plating metal into contact with the steel plate in a solid state, and melting the plating metal by the sensible heat of the steel plate preheated to temps. higher than the m.p. of the plating metal. CONSTITUTION:The atmosphere in a horizontal heating furnace 1 is maintained reducing or neutral by a gaseous mixture of H2 and N2, etc. and the temp. in the furnace 1 is maintained slightly higher than the prescribed preheating temp. of a steel plate (a) to be plated. Near the inlet 2 of the furnace 1, a solid plating metal 4 plate heated to near the melting temp. in a preheating furnace 5 is supplied onto the steel plate (a), and a roll 6 supports the plate (a) below the furnace 5. The plate (a) is fed through the inlet 2 into the furnace 1, and is heated to temps. higher than the m.p. of the plating metal 4 in the atmosphere in the furnace to melt the plate of the plating metal 4 with which it comes in contact on the roll 6, thereby forming the plated surface. The thickness (t) of the plating on the top surface of the plate (a) is controlled by changing the rate of supply of the plating metal 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a steel plate having one side metal plated.

Conventionally, zinc,
It is widely practiced to coat steel plates with metals such as tin and aluminum to improve their corrosion resistance.

These are usually plated by immersing the entire surface of the steel plate in a molten metal bath or an electroplating bath, so that both sides of the steel plate are coated. However, in some cases, from the viewpoint of product processability, appearance, economic efficiency, etc., it may not be necessary to coat both sides, and it may be preferable to coat only one side. Particularly in recent years, the demand for steel plates containing zinc or other nuclides on only one side has been increasing as rust-proof steel plates for automobiles and appliances, and in order to meet this demand, various methods of manufacturing single-sided plated steel plates have been proposed. ing. For example, there is a method that involves plating both sides and then mechanically removing the plating layer on one side.
This method has problems with product quality and workability. 1. There is a method of applying a plating inhibitor to one side of the plate and removing the inhibitor after plating, but this method makes it difficult to remove the inhibitor after plating and has problems with workability and positive results. There are some. Furthermore, methods have been devised to bring the molten metal into contact with only one side of the steel plate using ultrasonic waves, electromagnetic force, surface tension effects, etc.; Problems remain in that it is sometimes difficult to prevent this, and it has not yet been possible to obtain a stable coating.

This invention provides a new hot-dip plating method that is fundamentally different from these methods, in which the embedded metal is supplied in a solid state to the surface of the steel plate base material, and the plating method is applied using the sensible heat of the base material. The plating is completed at the same time as the plating metal is melted at the contact area.

Next, the method for manufacturing a steel plate with metal plating on one side according to the present invention will be explained by explaining one of the illustrated apparatuses for carrying out the present invention. In the drawing, 1 is a horizontal heating furnace, The atmosphere inside the furnace is kept reducing or neutral with a mixed gas of hydrogen and nitrogen, and the temperature inside the furnace is maintained somewhat higher than the predetermined preheating temperature of the steel sheet to be plated. There is an inlet 2 and an outlet 3 on the other side. Near the inlet 2 of the heating furnace, a preheating furnace 5 for a plated metal plate 4, which is a solid plated metal, is installed vertically. Below the preheating furnace 5, a preheating furnace 5 is provided. A support roll 6 for the steel plate a to be plated is rotatably provided.

In the method according to the present invention, which is carried out by the above-mentioned apparatus, a steel plate a to be plated whose surface has been cleaned by degreasing and pickling is fed into a heating furnace 1 through an inlet 2, and passed over a support roll 6. During this time, the plated metal plate 4 is heated to a predetermined preheating temperature higher than the melting point of the plated metal by the time it reaches the support roll 6 from the inlet 2; The plated steel plate a is fed at a predetermined feeding speed, and is heated in the preheating furnace 4 to approximately the melting temperature of the metal, so that contact between the plated metal plate 4 and the steel plate to be plated is reduced. The portion is melted by the sensible heat of the plated steel plate a, which is heated to a temperature higher than the melting point of the plated metal plate 4, and is immediately coated on the surface of the plated steel plate a.

Note that if the plated metal plate 4 is preheated in the heating furnace 5 to near the melting point of the plated metal as described above, the preheating temperature of the plated steel plate a can be set somewhat lower.

In the method of this invention, any metal that is commonly subjected to melt plating, such as zinc, tin, aluminum, lead-tin alloy, zinc-aluminum alloy, etc., can be used as the plating metal.

In addition, in the above embodiments, a metal plate was used as the plating metal, but the shape may be powder, foil, plate, etc., but except in special cases, it may be in the form of a plate with the same width as the steel plate. It is most convenient to use

In addition, the thickness t of the plating is determined by the supply rate of the plating metal,
That is, it is controlled by changing the amount of plating metal supplied per unit surface area of the steel plate.

Furthermore, the preheating temperature of the steel sheet must be sufficient to give the supplied plated metal the amount of heat necessary to melt it, and this temperature is dependent on the plated metal feed rate (i.e. It is determined by the plating thickness), the specific heat of the plating metal, the heat of fusion, the preheating temperature of the plating metal, the ambient temperature, etc., but it is 10' to 100°C below the melting point of the plating metal.
A high temperature is chosen.

In the above embodiment, the steel plate a to be plated is supplied horizontally, and the plating metal is supplied to the surface of the steel plate a to be plated as the plated metal plate 4. Alternatively, the steel plate to be plated may be moved vertically from the bottom to the top, or from the top to the bottom, while the plated metal plate is fed from the side of the plated steel plate a. It's okay.

According to the Kome invention, single-sided plated steel plates of uniform quality can be manufactured with good workability using simple equipment, so single-sided plated steel plates can be supplied at low cost.

Next, an example will be given.

A coiled steel plate with a thickness of 0.25 mm and 280 mm is degreased and pickled to clean the surface, and the inside of the heating furnace 1 is heated with 30% hydrogen.
, reduced with a 70% nitrogen gas mixture, temperature Fi, 64
Holding 0''CK, the steel plate a is passed through the heating furnace 1 at a speed of 5 m/min O:), and the contact surface between the zinc plate and the steel plate is heated to 460°C.
Also, the zinc plate 3 has a thickness of 101II
+1 Using a plate shape with a width of 280u, 482B/min
The temperature in the plating metal plate heating furnace 5 was set at 400°C, and the atmosphere was the same as that in the heating furnace 1, with a mixed gas of 3° hydrogen and 70% hydrogen. Therefore, the single-sided galvanized steel sheet manufactured in this way has a basis weight of 6011/rr? It was uniform and no zinc adhesion was observed on the back side.≦

[Brief explanation of the drawing]

The drawing shows a longitudinal sectional front view of an example of an apparatus for carrying out the method of manufacturing a steel plate plated on one side over the entire area according to the present invention. Patent applicant Kawatetsu Steel Sheet Co., Ltd.

Claims (1)

[Claims] A solid plating metal is supplied to one side of a steel plate that has been preheated to a temperature higher than the melting point of the plating metal, and the plating metal is melted by the heat given by the steel plate at the contact surface between the steel plate and the plating metal, and at the same time A method for manufacturing a steel plate with metal plating on one side, characterized by completing the coating.