JPH04329862A - Ti-containing alloy plated steel sheet excellent in workability - Google Patents

Abstract

PURPOSE:To produce a Ti-contg. alloy plated steel sheet excellent in workability by vacuum deposition. CONSTITUTION:When a Ti-contg. alloy film is formed on the surface of a steel sheet, a pure Ti underlayer is formed at an interface between the steel sheet and the alloy film in 0.01-2mum thickness and the (002) faces are preferentially oriented so that they are in parallel to the steel sheet. Thus, a Ti-contg. alloy plated steel sheet excellent in workability is obtd.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium-containing alloy plated steel sheet that requires particularly good workability, such as for use in automobile outer panels.

0002

[Prior Art] In the past, alloy coatings containing Ti were known to be excellent coatings from the viewpoint of corrosion resistance, but due to the high melting point of Ti, it was difficult to manufacture them by hot-dip plating.
It can only be manufactured by vacuum evaporation.

However, Ti produced by vacuum evaporation method
Alloy-plated steel sheets have weak adhesion between the plating and the steel sheet interface.
When used in applications that require particularly high workability, such as automobile exterior panels, it peels off from the interface between the steel plate and the plating, so it could only be applied to items that require little processing.

[0004] These interfacial peelings occur because the adhesion between the steel plate and the plating is weak, and one of the causes is that the elements contained in the steel plate and the elements contained in the plating are completely different. This is a fundamental problem in manufacturing alloy-plated steel sheets containing Ti.

[0005]

[Problems to be Solved by the Invention] The present invention relates to an alloy-plated steel sheet containing Ti that is manufactured by a vacuum evaporation method, an ion plating method, etc., and provides an alloy-plated steel sheet containing Ti that has excellent workability. It is intended to.

[0006]

[Means for Solving the Problems] The gist of the present invention is (00
2) 0.00 mm with preferential orientation so that the plane is parallel to the steel plate surface.
A Ti-containing alloy plated steel sheet with excellent workability is characterized by having a base layer made of pure Ti with a thickness of 01 μm or more and 2 μm or less and a coating made of a Ti-containing alloy as a surface layer.

[0007] The knowledge and idea that formed the basis of the present invention will be shown below. The inventors believed that the interfacial adhesion could not be improved by directly forming a film of an alloy containing Ti on the steel plate, and therefore aimed at a method of improving the interfacial adhesion by interposing a different type of film between the two. . This is a method known to those skilled in the art as underplating.

In general, compared to the film between a steel plate and an alloy containing Ti, the film between Ti and an alloy containing Ti contains a common element and the composition changes slowly at the interface, and is known as a so-called functionally graded material. The adhesion is very strong, just like the ones that have it.

[0009] By providing one layer of pure Ti film as a base for the Ti-containing alloy film, the workability of the Ti-containing alloy film and the base plating is improved. Therefore, in order to improve workability, it is sufficient to examine the adhesion between the steel plate and the base plating.

[0010] As a result, the inventors found that very strong interfacial adhesion exists between the steel plate and pure Ti, and that the structure of the pure Ti plating preferentially orients the (002) plane of pure Ti parallel to the steel plate surface. It was discovered that if the steel plate has a structure in which the steel plate is coated, the plating will not peel off when processed, and by applying this finding, the adhesion between the steel plate and the base plating was improved.

[0011] This shows that pure Ti (00
2) In the case of a structure in which the planes are preferentially oriented parallel to the surface of the steel plate, the difference between the deformation mode of the steel plate and the deformation mode of Ti becomes small, so it is thought that peeling does not occur at the interface.

Furthermore, it has been experimentally confirmed that generating plasma between the steel sheet and the evaporation source is effective in achieving preferential orientation in the crystal direction (002) using either the vacuum evaporation method or the ion plating method.

[0013]

[Operation] Next, the limiting conditions of the present invention will be shown. The present invention is characterized in that a pure Ti layer is formed between the steel plate and the alloy plating containing Ti, and the (002) plane of the pure Ti layer is preferentially oriented parallel to the steel plate surface.

Therefore, the film on pure Ti may be made of any alloy as long as it contains Ti, including all alloys determined from other conditions such as corrosion resistance and abrasion resistance.

In addition, the thickness of the pure Ti layer needs to be 0.01 μm or more because if it is thin, the crystals cannot be preferentially oriented in the (002) plane and a film cannot be formed. The upper limit was set to 2 μm or less since this would lead to no problem and an increase in cost.

[0016]Although ion plating is usually used to achieve preferential orientation toward the (002) plane, other methods may be used as long as preferential orientation can be achieved.

[0017]

[Example] An example carried out based on these findings will be described. Table 1 shows the results of plating pure Ti on a steel plate by vacuum evaporation and ion plating, and examining the workability.

Two types of vacuum evaporation methods are used: one is a method in which evaporation is performed using only an evaporation source and a substrate, and the other is a method in which plasma is generated by high-frequency discharge in the space between an evaporation source and a substrate. It's a method.

In the ion plating method, plasma is also generated in the space between the evaporation source and the substrate by high-frequency discharge, but there are two types of voltage applied to the substrate (-1.0, -2. 0volt).

[0020] The plating thickness is 2 μm in all cases. For evaluation of workability, a tensile test was used, and the presence or absence of peeling of the plating layer was investigated by observing the cross section after breaking.

When the Ti film is manufactured by vacuum evaporation, the diffraction pattern from the Ti film shows no crystal orientation, similar to that of powder, and when processed, the Ti film and the steel plate are separated.
Peeling occurs at the interface.

However, it can be seen that peeling does not occur when a film is formed with preferential orientation in the (002) plane using a vacuum evaporation method using plasma and an ion plating method.

[0023]

[Table 1]

[0024]

As described above, according to the method of the present invention, it becomes possible to apply alloy-plated steel sheets containing Ti to areas that were conventionally unusable due to poor workability.

Claims (1)

[Claims] Claim 1: When forming a film of an alloy containing Ti on the surface of a steel sheet, a base layer made of pure Ti is formed at the interface between the steel sheet and the film with a thickness of 0.01 μm or more and 2 μm or less, and (002).
An alloy-plated steel sheet containing Ti, which has excellent workability and is characterized by preferential orientation such that the plane is parallel to the steel sheet.