JPS58104164A - Production of aluminum plated steel material - Google Patents

Abstract

PURPOSE:To apply Al plating on the surfaces of steel materials by sticking Al on the surfaces of the steel materials, melting the same at temp. lower than the m.p. of the Al, and heating the steel materials in an inert atmosphere furnace together with fluxes of fluorides, chlorides and borides which are active in a molten state but have no activity and hyg roscopicity after cooling and solidifying. CONSTITUTION:A belt-like steel plate 1 is un-coiled, is fed continuously, is wound like a pipe with a roll former 2, and is made into an electric welded pipe with a resistance welding device 3 and a reducing device 4. Alis melt-sprayed to the electric welded pipe from a melt spraying device 5, and fluxes of fluorides, chlorides, and borides and their mixtures, for example, a mixture of AlF3 and KF is melt-sprayed from a melt spraying device 6. While the pipe passes between high frequency coils 8, the pipe is heated to temp. higher than the m.p. of the Al, by which the Al is melted. The parts of the coils 8 are enclosed by a tube 9 of an inert atmosphere to prevent oxidation of the steel pipe during heating. Further while the pipe is fed in the tube 9, the pipe is cooled and the Al plating is thus applied on the surface of the steel pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing aluminum-plated steel materials, and particularly to a method suitable for aluminum-plating coiled steel materials such as wires, tubes, and strips in a simple manner and at high speed. It is.

Various methods have been used to produce aluminum-plated steel materials, but all of them involve passing the steel material through a bath of molten aluminum, which reduces energy loss and requires a large, high-temperature melting tank. It was a great way.

In addition, in order to improve the adhesion between steel and aluminum, as shown in Japanese Patent Publication No. 55-43502, when passing the steel wire through a molten aluminum bath, ultrasonic vibrations are applied to the steel wire through a die, and the surface of the steel wire is reduced in advance. In order to perform high-quality plating, such as heating and reduction in a hostile atmosphere, the equipment required is complicated and expensive.

The purpose of the present invention is to achieve simple and high productivity for steel materials.
-''', 4:,::AM Aluminum plating method The present invention was made by focusing on the following points. That is, it is possible to plate aluminum on steel without using a molten aluminum bath. , by making an appropriate amount of aluminum adhere to the surface of the steel material and melting it at a temperature below the melting point of aluminum,
Aluminum is plated on the surface of steel by heating it in an inert atmosphere furnace together with a solvent that is activated as a solvent in the molten state but has no activity or hygroscopicity after cooling and solidifying.

With this method, there is no fear that the material to be plated will be corroded even if the solvent is not removed after plating. British Patent No. 1,055,
9 j4 contains 53-55% AlF3 and 47-45%
Anoshi and minium brazing, which has a melting point of about 560°C, can be made by mixing kF of 100%. Oka 1, □・,,'Leak ya 16 □6 U4°.

It is said that a non-hygroscopic substance is produced after completion of the process.

The present invention uses these solvents that are activated by melting below the melting point of aluminum, remove oxides from steel and aluminum at temperatures above the melting temperature of aluminum, fully wet the steel and aluminum, and then become non-hygroscopic after cooling. This is a method for aluminum plating of steel materials. British Patent No. 1,05
When used for joining aluminum as in No. 5,914, the joining temperature must be within a narrow range of below the melting point of aluminum and above the melting points of the brazing agent and solvent. However, when used for the purposes of the present invention, the solvent must have a melting point at least below the melting point of pure aluminum and be non-hygroscopic after solidification. As long as these two conditions are met, the component ratio does not matter much.

In addition, it melts below the melting point of aluminum, activates it,
If the acid film can be removed and the solid phase becomes a non-hygroscopic mixture after cooling, use the other 7""Ill.

It may also be a chloride, a chloride, a boride, or a mixture thereof.

An inert atmosphere is used only to remove oxides from steel materials, and an inert atmosphere is used for another function of solvents, which is to cover the surface of steel materials with molten solvent and prevent re-oxidation. This is to reduce the amount of solvent used.

An embodiment of the present invention will be described below with reference to FIG.

Figure 1 shows an example in which the present invention is implemented in synchronization with a manufacturing line for resistance welded steel pipes, in which 1 is a coil of a strip-shaped steel plate that is the raw material, 2 is a roll former for pipe making, and 13 is a resistance welded pipe. device, 4 is a welded pipe reducing device;
5 is an aluminum thermal spraying device, 6 is a solvent thermal spraying device, 7
8 is a high frequency oscillator, 8 is a high frequency coil, 9 is a cooling tube in a nitrogen atmosphere, and IO is a tube cutting device.

The raw steel strip 1 is unrolled and continuously fed, wound into a tube by the roll former 2, the seam is welded by the resistance welding device 3 to form an electric resistance welded tube, and the required pipe diameter is adjusted by the reducing device 4. The tube is contracted to become , aluminum is sprayed at step 5, a mixture of AlF3 and kl'i' is sprayed at step 6, and the aluminum is heated above the melting point of aluminum by passing between the high frequency coils at step 8, melting the aluminum. Steel pipes are work hardened by reducing annealing. The coil portion 8 is surrounded by the nitrogen atmosphere tube 9 to prevent oxidation during heating of the steel pipe. The steel pipe, molten aluminum, and solvent are cooled while being sent through the nitrogen atmosphere tube, and after the solvent turns into a solid phase, it exits the tube and is cut into the required length by 10 cutting machines. The solvent is non-hygroscopic and does not need to be removed from the surface of finished aluminized steel pipe in general applications.

According to the above method, high-quality aluminum-plated steel pipes can be manufactured at a speed synchronized with a highly efficient pipe-making line, and the economical effects are very large.

In addition, as for the equipment, only a 5.6 thermal spraying device is added.
The high frequency oscillator, coil 8, nitrogen atmosphere tube 9, etc. are very simple, as they can be used as they are for removing work hardening from reduced steel pipes.

In this example, a mixture of AlF3 and kF was used, but the solvent mixture may be different from that in the example, as long as it melts below the melting point of aluminum and has no activity or hygroscopicity after resolidification. Since thermal spraying is used, it is easy to change the adhesion resistance of aluminum and solvent, and even for materials where it is difficult to mix the solvent components, a good mixture can be obtained by spraying with separate thermal spraying heads. You can also do it. Furthermore, materials that are soluble in water and therefore difficult to apply using water can be easily deposited by thermal spraying. A method in which a water-insoluble solvent is pulverized, suspended in water, and applied to steel pipes is also within the scope of the present invention, but in the case of the example shown in Figure 1, the process is continuous, so there is no time or space to dry the water. Therefore, thermal spraying is advantageous in that it does not introduce moisture into the nitrogen atmosphere.

Figure 2 shows a similar electric resistance welded pipe line in which aluminum powder and a mixture of AlF2 and kF are melted, re-solidified to make them water-insoluble, and then finely powdered to attach aluminum and solvent to the steel pipe. This was made into a suspension in methanol and applied to a steel pipe in the nitrogen atmosphere in step 9 using the flow foot device 11, and then passed through the heating coil in step 8 to decompose the methanol, melt the solvent, and melt the aluminum. This is an example of a device that continuously applies aluminum plating to the surface of copper tubes by causing

The features of this example are that aluminum powder and fine solvent powder are suspended in methanol to prevent moisture from being brought into the nitrogen atmosphere, and that they are fed to the heating section without drying due to high-speed feeding. The amount of methanol used is very small, and even if it is decomposed into hydrogen and carbon monoxide, it does not have a negative effect on the nitrogen atmosphere, but rather works to strengthen the reduction effect of the oxides in the steel material.

Furthermore, since the methanol 70-coat equipment is circulated in a nitrogen atmosphere, methanol can prevent moisture absorption, which is excellent in terms of quality maintenance and economical efficiency.

According to the present invention, highly reliable aluminum plating on the surface of steel material can be performed with a simple device and with high efficiency, so the economical effect is great.

[Brief explanation of drawings]

FIG. 1 is a side view schematically showing the lines of one embodiment of the present invention, and FIG. 2 is a side view schematically showing the lines of another embodiment of the present invention. ■...Material coil, 2...Roll former-13.
- Bite resistance welding machine, 4... Reducer - 55... Thermal spraying device, 6... Thermal spraying device, 7... - High frequency oscillator, Death... Heating coil, 9... Nitrogen atmosphere tube, lO.
...Cutting device, 11...Flow coater〒. Figure 1 ( 1 (

Claims (1)

[Claims] ], fluorides, chlorides, halides and A method for producing aluminized steel material, characterized in that a solvent consisting of a mixture thereof is attached to the surface of steel material together with aluminum, and heated in an inert atmosphere furnace to melt the aluminum. 2. The method for producing aluminum-plated steel material according to claim 1, characterized in that thermal spraying is used to attach the aluminum and solvent to the steel material. 3. Claim 1, characterized in that the solvent and aluminum are attached to the steel material by suspending the solvent powder and the aluminum powder in a liquid and applying the suspension to the surface of the steel material.
A method for producing aluminum plated steel material as described in Section 1. 4. The method for producing aluminized steel material according to claim 3, wherein the liquid in which the solvent powder and aluminum powder are suspended is methanol.