JPS62267465A - Method for detecting contamination of surface of molten metal in deposition chamber of continuous vacuum deposition apparatus - Google Patents

Abstract

PURPOSE:To correctly detect the contamination level of the surface of a molten metal by measuring the thickness of a metallic film vacuum-deposited on a hoop, the temp. of the molten metal and the opening degree of a shutter and by calculating a coefft. from the measured values. CONSTITUTION:The thickness of a metallic film vacuum-deposited on the surface of a hoop 10 introduced into a vacuum deposition chamber 1 is measured at the outlet of the chamber 1. The temp.of a molten metal 11b in the chamber 1 and the opening degree of a shutter are also measured and a coefft. is calculated from the measured values. The contamination level of the surface of the molten metal is detected by making use of the fact that the thickness of the metallic film is proportional to the temp. of the molten metal 11b and the opening degree of the shutter but is reduced when the surface of the molten metal 11b is contaminated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting contamination on the surface of molten metal in a deposition chamber of an apparatus for continuously vacuum depositing a metal film on a steel strip.

[Conventional technology]

In a conventional continuous vacuum deposition apparatus, a part of which is shown in the longitudinal cross-sectional view of FIG. Due to the pressure difference, the steel strip 10 is sucked up to the vapor deposition tank 3 via the snorkel 7, and the temperature is adjusted by the heating control of the main heater 6 and the opening degree of the shutter 4 is controlled.
The amount of evaporation is adjusted to match the predetermined basis weight (deposition amount per unit area).

Band @ 1 heated to an appropriate temperature and continuously fed into the deposition chamber 1
Is 0 a winding roll? When the steel strip is wound around the steel strip and passed through, the metal vapor evaporated from the evaporation tank 5 reaches the surface of the steel strip through the channel 2, and since the temperature of the steel strip 10 is lower than the solidification temperature of the metal vapor, it solidifies on the surface. , deposited.

During this time, metal oxides caused by a small amount of oxygen in vacuum on the surface of the molten gold 1d11b, metal compounds generated in the melting tank 8, and other impurities are sucked up to the evaporation tank 3 together with the molten gold lfJ 11a, and the main heater As they are heated and evaporated in step 6, they gradually cover the surface of the molten metal 11b, resulting in a decrease in the amount of evaporation, that is, an insufficient basis weight.

Conventionally, after a certain period of time has elapsed, the melting tank 8 is lifted upwards to temporarily raise the surface of the evaporated N5 melting metal 11b as shown by the two-dot chain line, and the scraper 5 removes dirt on the surface. substance was removed.

[Problem that the invention seeks to solve]

However, the rate at which dirt accumulates on the surface of the molten metal in the evaporation chamber is not constant, and with methods that rely on the operator's intuition, if removal work is delayed, too much dirt accumulates and covers the surface, reducing the evaporation area. At the same time, the temperature decreases due to poor absorption of radiant heat from the main heater 6, and the amount of evaporation decreases, resulting in insufficient thickness of the deposited film, and fine particles of the metal compound, which is a cause of contamination, are mixed with the metal vapor. There were problems such as reaching the surface and adhering to it, causing deterioration of the surface quality.

Furthermore, even though there is little dirt, removal work is sometimes performed, so operations such as moving the dissolving tank 8 up and down and operating the scraper 5 are wasted.

〔the purpose〕

The present invention was proposed to solve these problems, and by constantly detecting contamination on the surface of molten metal in the deposition chamber and removing the contamination when it reaches a certain value, stable high quality can be achieved. It is an object of the present invention to provide a dirt detection method that improves work efficiency while obtaining a metal vapor-deposited film.

[Means for solving problems]

In order to achieve the above object, the present invention selects the thickness of the metal coating at the outlet of the vapor deposition chamber, the temperature of the molten metal in the vapor deposition chamber, and the shutter opening degree as factors for detecting contamination on the surface of the molten metal in the vapor deposition chamber. This method detects these changes to detect dirt on the surface of the goldfly. That is, in the present invention, when a steel strip is passed through a vapor deposition chamber and a metal is continuously vapor deposited on the surface thereof to form a metal coating, the thickness of the metal coating detected at the exit of the vapor deposition chamber, The method for detecting contamination on the surface of molten metal is characterized in that the degree of contamination on the surface of the molten metal is detected based on a change in a coefficient calculated from the temperature of the molten metal in the vapor deposition chamber and the shutter opening degree.

[Effect]

To explain the present invention in detail, if the line speed is constant, the thickness of the metal coating deposited on the steel strip is proportional to the temperature of the molten metal in the deposition chamber and the shutter opening, and originally the coefficient is However, in the present invention, as the surface of the molten metal becomes dirty, the evaporation area decreases and the value of the coefficient decreases, which is used to detect the degree of contamination.

〔Example〕

The present invention will be explained in detail below with reference to FIGS. 1 and 2. FIG. 1 is a vertical sectional view showing the main parts of a continuous vacuum evaporation apparatus suitable for the dirt detection method according to the embodiment of the present invention, and FIG. 2 shows various film thickness dimensions, that is, various required evaporation amounts.
4 is a graph showing the relationship between melt temperature T (° C.) and shutter opening El (S) versus (evaporation amount f/min per unit time).

As shown in FIG. 1, a film thickness detector 12 disposed at the outlet of the vapor deposition chamber 1 detects the film thickness of the metal coating deposited on the surface of the steel strip 10 to be passed. will be displayed. Furthermore, the temperature T near the surface of the molten metal 111) is detected by a thermocouple 14 installed in the evaporation tank 5 and displayed on a thermometer 15. In addition, in FIG. 1, 16 is a shutter opening degree meter.

By the way, the so-called basis weight Q, which is the amount of vapor deposition per unit area, is calculated based on the film thickness, which is an actually measured value. From this weight Q, the plate width W of the steel strip 10, and the predetermined line speed LS, the required evaporation amount G per unit time is calculated using the following formula, and the shutter opening degree S is further calculated from the temperature T of the actual σI11. .

cJ-T, +5XWXQ @---- (1) Formula S
-f (G, T, K)...Equation (2) [K in the above equation (2) is the shutter opening coefficient. ] According to the above equation (2), if the shutter opening degree coefficient K is constant, the shutter opening depending on the temperature T of the molten metal 11b at G4 is determined by the graph shown in FIG. Degree S is required. However, as dirt increases on the surface of the molten metal 111), its evaporation ability decreases, and the shutter opening coefficient K, which was initially 1, becomes, for example, α9. (It gradually decreases like 18,117.

Since the shutter opening S and temperature T are controlled by the basis weight Q calculated from the actually measured film thickness and the required evaporation amount G is maintained, the shutter opening S and temperature T are detected and the above ( The shutter opening degree coefficient K is calculated by the following equation (3) which is calculated backward from equation 2).

K - f (S, G, T) ... Equation (3) If contamination on the surface of the molten metal 111) is detected by this decrease in the shutter opening coefficient, and if it decreases to a value such as α7, then While the dirt substances are removed by the scraper 5, the shutter opening degree S, which has been increased, is increased by the area weight Q, that is, the evaporation amount G.
is lowered as the amount of evaporation G increases, and the required amount of evaporation G is maintained.

〔effect〕

As detailed above, the present invention detects the thickness of the metal coating deposited on the steel strip, the temperature of the molten metal in the deposition chamber, and the shutter opening degree, and calculates the coefficient based on these values. This has the effect of accurately detecting the degree of contamination on the surface of the molten metal. Through this detection, it is possible to remove the contamination in a timely manner, and as a result, it is possible to prevent deterioration of the surface quality of the metal coating and decrease of the film thickness. This has the remarkable effect of preventing the decrease.

[Brief explanation of drawings]

Fig. 1 is a longitudinal plane view showing the main parts of a continuous vacuum evaporation apparatus suitable for the contamination detection method which is an embodiment of the present invention, and Fig. 2 shows various required evaporations 1t()i to G4 (unit time Temperature of molten metal relative to the amount of evaporation (27 minutes)? It is a graph showing the relationship between (° C.) and shutter opening degree S (chi). Third
The figure is a longitudinal sectional view showing the main parts of a conventional continuous vacuum evaporation apparatus. 1... Vapor deposition chamber 9... Winding roll 2...
Channel 10...Strip 3...Evaporation tank
11a, 11b... Molten metal 4... Shutter 1
2...Film thickness detector 5...Scraper 15...Film thickness meter 6 Prefecture...Main heater 14...-Thermocouple 7 ・1 snorkel 15 ■Thermometer 8 days・Melting tank 16■ - Shutter opening meter sub-agent
1) Meifuku agent Ryo Hagiwara − Sub-agent Takao Anzai

Claims (1)

[Claims] When passing a steel strip into a vapor deposition chamber and continuously vapor depositing metal on its surface to form a metal coating, the thickness of the metal coating detected at the exit of the vapor deposition chamber and the molten metal in the vapor deposition chamber are measured. A method for detecting contamination on a molten metal surface, characterized in that the degree of contamination on the surface of the molten metal is detected based on a change in a coefficient calculated from the temperature of the molten metal and the shutter opening degree.