JPH11181561A - Masking method for hot dip plating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a coating layer by hot dip plating only on desired one part in the surface of the object to be treated. SOLUTION: This method is composed of a stage in which slurry obtd. by mixing ceramics powder, an organic binder and an organic solvent is applied to a specific part in the surface of the object 1 to be treated, a stage in which the object to be treated is heated to dry the surface, and coating 4 covering the specified part is formed, a stage in which the object to be treated in which the coating is formed on the specified part is immersed into a hot dip metal 5, which is pulled up, the hot dip metal is solidified, and a metallic coating layer is formed on the surface at least including the whole body of the surface other than the specified part and a stage in which the coating and the metallic coating layer are removed from the specified part of the object to be treated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot-dip plating method, and more particularly, to a hot-dip plating masking method in which only a desired portion of the surface of a workpiece is coated with a metal coating layer.

[0002]

2. Description of the Related Art In a hot-dip plating method, an object to be processed is immersed in a molten metal, which is pulled up to form a metal coating layer on the surface of the object to be processed, and the object to be processed is subjected to corrosion resistance, oxidation resistance, and wear resistance. sex,
This is a surface treatment method that imparts and strengthens properties such as heat resistance. In this hot-dip plating method, zinc or tin, aluminum, or the like is used as a molten metal, mainly using a steel material as an object to be processed.

[0003] Hot-dip galvanizing can improve the corrosion resistance of machine parts, and hot-dip aluminum plating can enhance the heat resistance and corrosion resistance of machine parts.

The application range of the hot-dip plating method is wide, and it is used for surface treatment of various mechanical parts such as building materials, parts of home electric appliances, automobile parts and the like.

[0005]

According to the hot-dip plating method, a thick coating layer can be easily obtained on the surface of the object to be processed, but the molten metal is adhered to the surface by immersing the object in the molten metal. Therefore, there is a problem that the coating layer cannot be formed only on a desired specific portion of the surface of the object to be processed, depending on a place where the coating layer is formed. This is different from the thermal spraying method in which a coating layer can be formed on a limited portion of the surface of the workpiece.

[0006] Also, mechanical parts have mechanical properties that need to be strengthened by surface treatment, such as requiring that some parts of the surface have corrosion resistance and some other parts have particular wear resistance. Different parts have different mechanical parts. Even if hot-dip plating is suitable for surface treatment of such mechanical parts,
As described above, since the coating layer cannot be formed only on a desired part, there is a problem that hot-dip plating cannot be applied to this kind of mechanical part.

[0007] When steel is plated with hot-dip aluminum, the alloy layer formed between the surface of the steel and the coating layer is
It consists of intermetallic compounds of very hard and brittle nature. For this reason, there is also a problem that it is difficult to perform a process for correcting the deformation of the processing object generated in the process of the hot-dip plating process.

Accordingly, an object of the present invention is to provide a masking method for hot-dip plating which solves the above-mentioned problems of the prior art and can form a coating layer by hot-dip plating only on a desired part of the surface of the object to be processed. To provide.

[0009]

In order to achieve the above-mentioned object, the present invention provides a step of applying a slurry obtained by mixing a ceramic powder, an organic binder and an organic solvent to a specific portion of the surface of a workpiece, Heating the object to be processed and drying the surface thereof to form a film covering the specific member, and immersing the object with the film formed in the specific part in a molten metal, and pulling up and melting the object. A step of solidifying the metal to form a metal coating layer on a surface including at least the entire surface other than the specific portion of the object, and a step of removing the film and the metal coating layer from the specific portion of the object , Consisting of:

[0010] According to the present invention, since the film is formed so that it hardly reacts with the molten metal to be immersed and can be easily removed, and then is immersed in the molten metal, the film is limited to only a desired part and can be easily formed. Can be subjected to hot-dip plating.

The ceramic powder used in the slurry is boron nitride powder or zirconium oxide powder,
The organic binder is preferably a thermosetting resin such as an acrylic resin or an epoxy resin.

Further, the present invention can be applied to hot-dip plating in which a tool detachable part of a machine tool spindle is an object to be processed, and the slurry is applied to a surface other than the inner peripheral surface of the object to be processed. Hot-dip plating is performed only on the inner peripheral surface, so that performance such as wear resistance can be improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for masking hot-dip plating according to the present invention will be described below with reference to the accompanying drawings. As an example of an embodiment of the present invention, an example will be described in which the present invention is applied using a tool detachable part of a machine tool spindle as an object to be processed. FIG. 1 shows a longitudinal section of a tapered sleeve which is a tool detachable part of a spindle.

A tapered hole 2 is formed in the inner diameter of the tapered sleeve 1 so that the tapered shank of the tool holder fits therein. Hot-dip plating is applied to the inner peripheral surface 2a of the tapered hole portion 2 of the entire outer peripheral surface and inner diameter portion of the tapered sleeve 1. FIG. 2 illustrates this step.

First, the tapered sleeve 1 is cleaned as a pretreatment, and then, as shown in FIG. 2A, of the entire surface of the tapered sleeve 1, the inner peripheral surface 2a of the tapered hole 2 is formed.
A slurry 3 prepared by mixing a ceramic powder, an organic binder, and an organic solvent is applied to the other surfaces. As the ceramic powder, boron nitride powder, zirconium oxide powder and the like are preferably used. As the organic binder, a thermosetting resin such as an acrylic resin or an epoxy resin is used. An organic solvent is added to such a ceramic powder and an organic binder and mixed until a slurry is formed.

Next, as shown in FIG. 2B, the tapered sleeve 2 coated with the slurry 3 is placed in a heating furnace, heated at a predetermined temperature, and dried. By this drying step, a thin film 4 is formed on the outer peripheral surface and the inner peripheral portion of the tapered hole portion 2 except for the inner peripheral surface 2a, in which the ceramic powder is dispersed in the organic binder and bonded. This film hardly reacts with a molten metal such as zinc or aluminum, and can be easily removed together with the metal coating layer by mechanical processing.

After the film 4 is formed in this way, the taper sleeve 1 is entirely or at least a lower part including the inner peripheral surface 2a is placed in the molten metal 5 as shown in the hot-dip plating step of FIG. After being immersed, it is raised. The entire surface of the tapered sleeve 2 is covered with a solidified metal coating layer.

In this hot-dip plating step, the entire or lower surface of the tapered sleeve 1 is covered with the metal coating layer. Finally, as shown in FIG. 2D, the film 4 on the outer peripheral surface and the inner peripheral surface excluding the inner peripheral surface 2a of the tapered hole portion 2 and the metal coating layer laminated thereon are removed. For example, hot-dip plating can be performed only on the inner peripheral surface 2a of the tapered hole portion 2.

Further, since hot-dip plating limited to a desired portion can be performed, a process for correcting deformation can be performed on another portion not subjected to hot-dip plating.

[0020]

Next, the present invention will be described in more detail with reference to specific examples. This embodiment is an embodiment in which only the inner peripheral surface 2a of the tapered sleeve 2 shown in FIG. 1 is plated with molten aluminum.

In this embodiment, the tapered sleeve 1 is made of hot tool steel (JIS SKD61). Regarding the slurry, an acrylic resin was used as an organic binder for boron nitride powder, and toluene was mixed as an organic solvent. This slurry was applied to the surface of the tapered sleeve 1 excluding the inner peripheral surface 2a.

The heating and drying of the tapered sleeve 1 is performed at 110 ° C.
And heated for 1 hour. Then, in the hot-dip plating step after completion of drying, the tapered sleeve 1 was immersed in an aluminum bath at 670 ° C. for 5 minutes.

An aluminum coating layer is formed on the entire surface of the tapered sleeve 1 by the hot-dip plating.
The aluminum in the portion other than a was easily removed, and the boron nitride film was also removed together with the aluminum, and hardly remained. In this manner, the shank portion of the tool was fitted, and the inner peripheral surface 2a of the tapered hole 2 where the wear resistance was required was improved by the molten aluminum plating to improve the wear resistance.

[0024]

As is apparent from the above description, according to the present invention, a slurry in which a ceramic powder, an organic binder and an organic solvent are mixed is applied to a specific portion of the surface of the object, and the object is treated. Heating and drying the surface to form a film covering the specific member, immersing the object having the film formed in the specific portion in molten metal, pulling it up, solidifying the molten metal, and solidifying the molten metal A desired portion of the surface of the object to be processed by forming a metal coating layer on a surface including at least the entire surface other than the specific portion of the object to be processed and removing the film and the metal coating layer from the specific portion of the object to be processed. Thus, a coating layer can be easily formed by hot-dip plating.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a taper sleeve used for a tool attaching / detaching portion of a machine tool spindle to which a method for masking hot-dip plating according to the present invention is applied.

FIG. 2 is a process explanatory view of a hot-dip plating masking method according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Taper sleeve (object to be processed) 2 Tapered hole 2a Inner peripheral surface 3 Slurry 4 Film 5 Molten metal

Claims (3)

[Claims] A step of applying a slurry in which a ceramic powder, an organic binder and an organic solvent are mixed to a specific portion of the surface of the processing object; heating the processing object to dry the surface; A step of forming a covering film, and immersing the object having the film formed on the specific portion in a molten metal, pulling it up to solidify the molten metal, and at least a surface of the object to be processed other than the specific portion A masking method for hot-dip plating, comprising: a step of forming a metal coating layer on a surface including the whole; and a step of removing the film and the metal coating layer from a specific portion of the workpiece. 2. The ceramic powder used for the slurry is boron nitride powder or zirconium oxide powder,
The method according to claim 1, wherein the organic binder is a thermosetting resin such as an acrylic resin or an epoxy resin. 3. The object to be processed is a tool detachable part of a machine tool spindle, the slurry is applied to a surface of a specific portion of the object to be processed, and hot-dip plating is performed only on a surface of a desired portion other than the specific portion. 2. The method according to claim 1, wherein
Or the masking method for hot-dip plating according to 2.