JPH0158262B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a hard watch exterior part containing TiC as a main component. Here, the term "exterior parts for a watch" refers to a watch body, a glass wire, a reuse, a watch band, etc., and the watch body will be described in detail in particular.

In recent years, there has been a significant increase in the use of watch cases made of carbide materials, as they are said to be less prone to scratches. However, although such carbide watches have high hardness and do not get scratched, they have poor impact resistance, so they have the disadvantage of breaking when dropped.

The present invention eliminates such drawbacks, and uses TiC as the main component and binds Ni, Cr, Mo,
By distributing Fe in an appropriate proportion, the resistance is improved compared to conventional products, making it possible to manufacture a tough and highly hard carbide side. In addition, TiC is
WC and TaC are the main components of conventional carbide cases.
It has a lower specific gravity, and therefore exhibits excellent properties against drop impact.

In cemented carbide, in order to improve toughness, it is important to set the content of the bonding metal and the sintering conditions. In the present invention, high toughness, high hardness, and
Focusing on sinterability, Ni is 16.3 to 20% by weight,
Cr was set at 7 to 7.5%, and Mo was set at 5.1 to 6%. Also,
Although Fe is naturally introduced along with other components, if it is included in a large amount, it will cause a decrease in corrosion resistance, so care must be taken to keep it at 5% or less.

Furthermore, if Ni is less than 16.3%, sinterability will be poor, and if it exceeds 20%, wear resistance will be reduced.

If the Cr content is less than 7%, the color tone will be poor, and if it exceeds 7.5%, the sinterability will be poor.

If Mo is less than 5.1%, hardness will not be achieved, and if it exceeds 6%, the sintering temperature will increase.

HIP (Hot
Isostatie Press) treatment to create a sintered product, which was then subjected to electric discharge machining, polishing, and mirror finishing to give it the desired shape and finish, making it the watch side. The watch side obtained in this way has a resistance force of 140 to 160 Kg/mm ² ,
The hardness was Hv1000 to 1500, and the surface had a bright color luster. A suitable sintering temperature is 1500 to 1700°C.

This will be explained below using examples.

Example 1 All weight ratios are Ni16.3%, Cr7.5%, Fe1.4
%, Mo5.1%, balance TiC (particle size Ni: 1.5μ, Cr: 1.0μ, Fe: 1.2μ, Mo:
1.2μ, TiC: 0.8μ) was ground in a ball mill, these powders were mixed, pressed, and sintered at 1600°C in an argon atmosphere to form the raw material for the watch side. This raw material was then subjected to electrical discharge machining and polishing to form the watch side. It has a resistance of 150Kg/ ^{mm2 and} a Bitkers hardness of Hv1350, and the surface has a beautiful silvery white color, and it did not break even when dropped from a height of 1.5m. This is sufficiently practical considering that the watch is normally carried around.

In addition, in terms of corrosion resistance, saline solution (Nac: 5
%) and artificial sweat made from standard components of human sweat for one week, no rust occurred.

Example 2 Ni 20%, Cr 7.0%, Fe 1.5%, all by weight ratio
Example 1 A powder composition consisting of 6% Mo and the balance TiC was sintered (particle size and sintering conditions were the same as in Example 1).
The clock side was created using the same process as above. The transverse rupture force is
It had a hardness of 155Kg/mm ² Bitkers, Hv: 1230.
Regarding impact resistance and corrosion resistance, as in Example 1,
It showed good results.

According to the present invention, by mixing and sintering fine powders of Ni, Cr, Mo, and TiC in a predetermined ratio, the hardness of TiC and the sinterability and corrosion resistance of Ni, Cr, and Mo can be improved. The materials match very well and can be made into a material suitable for silvery-white hard watch exterior parts.

In particular, since the metal content is relatively high at around 30%, sintering is easy. For example, when used to make a watch case, polishing is relatively easy, and a smooth and glossy appearance can be obtained. It does not lose its metallic feel at all, and on the contrary, since TiC accounts for 60%, it does not reduce its hardness.
Since the metal component serves as a suitable binder, it has good impact resistance, and the alloy also has corrosion resistance, so it is possible to make a hard exterior part for a watch that has both impact resistance and corrosion resistance.

Claims (1)

[Claims] 1 All weight ratios are Ni16.3~20%, Cr7~7.5
%, Mo5.1 to 6%, Fe5% or less, the balance being TiC and inevitable impurities.