JPH059701A - Method for cutting titanium material - Google Patents

Abstract

PURPOSE:To improve the machinability of Ti or Ti alloy and to prolong the service life of a cutting tool by heat treating the member of the Ti or Ti alloy at a specific temp. or above. CONSTITUTION:The member made of the Ti or Ti alloy which is high in deformation resistance and is inferior in workability is previously subjected to the heat treatment to >=450 deg.C prior to cutting to form oxide scale of, for example, >=0.2mum thickness on the surface. Since the oxide scale is brittle and chemically inert, the easy cutting with the cutting tool is possible and the service life of the cutting tool used is greatly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for cutting a titanium material.

[0002]

BACKGROUND OF THE INVENTION Titanium materials are lightweight and have high strength, and also have excellent heat resistance and corrosion resistance. -It has a wide range of uses including consumer products such as mums and ornaments. However, the titanium materials have such excellent characteristics, but at present, the demand is not so large as that of steel, aluminum, and copper. This is because, in addition to the problem that the titanium material is expensive, there are many processing problems such as difficult cutting. That is, the titanium material has a large deformation resistance and is difficult to be processed. In addition to this, the titanium material has a low thermal conductivity, a small volume specific heat, and is chemically active at a high temperature, so that the tool life is short. Further, since the titanium material has high toughness, chips are continuously discharged, and the chip disposability is poor. Therefore, there is a problem that it is difficult to perform accurate cutting even under the optimum conditions and the processing cost is high. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for cutting a titanium material which has good workability and a long tool life.

[0003]

In order to solve the above-mentioned problems, the present invention is characterized in that a titanium material is subjected to a heat treatment at a temperature of 450 ° C. or higher and then cut. To provide a cutting method.

As a result of various investigations by the inventors of the present application to improve the machinability of titanium material, the machinability is determined by the characteristics of the surface layer of the titanium material, and a thin oxide scale is formed on the surface layer of the titanium material. It was found that the machinability of the titanium material can be improved by forming the. That is,
Titanium material itself has high deformation resistance, low thermal conductivity,
Volume specific heat is small, and it is chemically active at high temperatures, but titanium oxide is brittle and chemically inactive, so by forming an oxide scale on the surface layer,
It becomes easier to cut, and the tool life can be extended,
Moreover, chips can be discharged discontinuously. Therefore, in the present invention, a heat treatment is applied to the titanium material to form an oxide scale on the surface of the titanium material, thereby solving the problem of cutting of the titanium material.

Here, the reason why the heat treatment temperature is limited to 450 ° C. or higher is that if the temperature is lower than 450 ° C., the oxide scale is not sufficiently generated and the machinability cannot be sufficiently improved. A very thin oxide scale is enough,
It is preferably 0.2 μm or more.

In the present invention, the titanium material is intended to include both pure titanium and titanium alloy. Further, the cutting process here can be applied regardless of the cutting method and the type of the cutting tool. That is, the cutting methods are turning, milling, end milling,
Any kind of drilling, thread cutting, etc. may be used, and cutting tools such as high speed steel, carbide, coating tip, cermet, ceramics, CBN, diamond, etc. which are commonly used Such tools are also acceptable.

[0007]

Embodiments of the present invention will be described below.
Here, the titanium material has a thickness of 1.27 mm and an outer diameter of 95.
A blank material for a magnetic disk substrate made of pure titanium having an inner diameter of 20 mm and an inner diameter of 20 mm was used.

After heat-treating such a blank material under the conditions shown in Table 1 in the atmosphere, the inner circumference and the outer circumference were cut, and the machinability was judged by the life of the cutting tool.

As a cutting tool, carbide K-10 (Co
Content is 4-7%) and K-20 (Co content is 5-8)
%) And JIS W1 type 1 (Yushiro-ken EC-50T manufactured by Yushiro Kagaku Co., Ltd.) was used as a cutting oil.

The cutting tool life was evaluated by the number of blanks that can be cut by one tool. At this time, whether or not the tool life was reached was judged by the presence or absence of burrs on the blank material. That is, it was judged that the tool life had been reached when burr was generated. The tool life at this time is also shown in Table 1.

As is clear from Table 1, the heat treatment is performed at 450
It was confirmed that all of the blank materials of Examples carried out at a temperature of not less than ° C showed a good tool life of 150 or more blank materials per cutting tool. On the other hand, in the comparative example in which the treatment temperature was less than 450 ° C., the number of blank materials that could be cut was about 20 at most, and it was confirmed that the machinability was poor. Especially, it was shown that only one piece was not heat-treated at all, and the machinability was extremely poor. In addition,
As is clear from Table 1, it was also confirmed that the machinability was related only to the heat treatment temperature and was not affected by the heat treatment time.

[0012]

[Table 1]

[0013]

According to the present invention, there is provided a method of cutting a titanium material which has good workability and a long tool life.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Toshio Sakiyama 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Hiroyoshi Suenaga 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date (72) Inventor Yoshiharu Kida 3-25-17 Shichirigahama Higashi Higashi Higashi, Kamakura City, Kanagawa Prefecture

Claims (1)

Claim: What is claimed is: 1. A method for cutting a titanium material, which comprises subjecting a titanium material to a heat treatment at a temperature of 450 ° C. or higher, and then cutting the titanium material.