JPH1143760A - Titanium hardened member and hardening treatment therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To impart high hardness not so as to generate scratches to the surface of a titanium member while the surface state before hardening treatment is maintained by forming a surface hardened layer of a specified thickness in which nitrogen is allowed to enter into solid solution by a specified amt. by hardening treatment on the surface of a titanium member subjected to annealing treatment at a specified temp. in a vacuum atmosphere. SOLUTION: A titanium or titanium allay member is subjected to annealing treatment of heating at 700 to 800 deg.C by a heating means in a vacuum atmosphere. Then, the member subjected to the annealing treatment is treated at 700 to 800 deg.C for a prescribed time in an evacuated atmosphere in which a gas contg. nitrogen components is introduced, and nitrogen 20 is diffused and allowed to enter into solid solution to a depth of >=5 μm from the surface of the member without forming nitrogen compds. to form a surface hardened layer 18 in which the nitrogen 20 is allowed to enter into solid solution by 0.2 to 6.0 wt.% on the surface of the titanium hardened member 2. This titanium hardened member 2 is held at 700 to 800 deg.C for a prescribed time in an evacuated atmosphere in which helium or argon is introduced and is cooled to an ordinary temp. In this way, surface cracks are not generated on the titanium hardened member 2, and the formation of colored materials on the surface is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a titanium hardened member made of titanium and a titanium alloy and having its surface and inside hardened, and particularly to a watch case made of titanium and a titanium alloy used as a decorative article. , Watch bands, piercings, earrings, rings, eyeglass frames and the like.

[0002]

2. Description of the Related Art In recent years, titanium and titanium alloys have been attracting attention as human-friendly metals which are unlikely to cause metal allergy. Although the above concept is widely supported for decorative articles represented by watches, glasses, jewelry, etc., on the other hand, deterioration of appearance quality due to scratches during use has been pointed out as a major problem. This is mainly due to the low surface hardness of the member made of titanium and titanium alloy itself, and various surface hardening treatments have been attempted to solve the problem. The surface hardening treatment is roughly classified into a method of coating a hard film on the surface of a metal member and a method of hardening the metal member itself. As a method of coating a hard film on a metal member surface, a wet process typified by electroplating and a dry process typified by vacuum deposition, ion plating, sputtering, plasma CVD, and the like are known. Known methods for curing include ion implantation, ion nitriding, gas nitriding, carburizing, and the like.

[0003]

However, when a hard film is formed on a member made of titanium and a titanium alloy to increase the surface hardness of the member, the adhesion between the member and the film is difficult. Because the problem of film peeling has not yet been completely solved, and since a coating is applied directly on the member, it is not possible to obtain a surface hardened layer of titanium and titanium alloy as it is in the base metal color There were drawbacks.

In general, methods such as ion nitriding and gas nitriding are widely used as a method for hardening titanium and titanium alloys. However, when these methods are employed, a hardened surface hard layer having high hardness which is hardly scratched on the surface. In order to obtain Vickers hardness Hv of the surface at least Hv = 450
The above hardness is required. This Vickers hardness Hv = 4
In order to obtain 50 or more, the processing temperature must be set to 850 ° C. or higher. However, if the processing temperature is higher than 850 ° C., the crystal grains of the member become coarse and the surface becomes rough. In addition, since a compound of titanium and nitrogen typified by titanium nitride is formed and colored yellow, there is a problem that the surface state before the treatment is maintained and the hardening treatment cannot be performed while keeping the titanium base metal color. In addition, the processing time was long and there was a problem in productivity. Therefore, the object of the present invention is to
The member is hardened at a temperature at which surface roughness does not occur, and an appropriate concentration of nitrogen in titanium to prevent the formation of a coloring substance such as titanium nitride on the surface and a Vickers hardness Hv = 450 or more on the surface are required. The purpose is to find the appropriate thickness of the cured layer to obtain.

SUMMARY OF THE INVENTION An object of the present invention is to provide a member made of titanium and a titanium alloy, which does not cause surface roughness and does not form a coloring substance on the surface while maintaining the surface state before the treatment. It is an object of the present invention to provide a hardened titanium member made of hardened titanium and a titanium alloy which are hardened and are hardly scratched and a hardening method thereof.

[0006]

In order to solve the above-mentioned problems in the present invention, a heating means, a tray, and a member made of titanium and a titanium alloy are arranged in a vacuum chamber having a gas inlet and a gas outlet. After evacuation, a member made of titanium and a titanium alloy placed on a tray is heated to 700 to 800 ° C. by a heating means in a vacuum atmosphere or a reduced pressure atmosphere in which helium or argon is introduced into the vacuum chamber.
Heating for a predetermined time until the annealing process, annealing, and in a reduced pressure atmosphere in which a gas containing a nitrogen component is introduced, nitrogen is diffused from the surface of the member made of titanium and the titanium alloy to the inside by holding for a predetermined time at the same temperature as the heating process, At the same temperature as the hardening process in a reduced pressure atmosphere in which helium or argon is introduced after stopping the supply of the gas containing the nitrogen component and evacuating after stopping the supply of the gas containing the nitrogen component, A hardening treatment method characterized by performing a hardening treatment in three steps of a cooling step of cooling to room temperature after holding for a predetermined time, thereby obtaining a depth of 5 μm from the surface.
In the member made of titanium and a titanium alloy having the surface hardened layer formed as described above, the surface hardened layer has a thickness of 0.1 mm.
A titanium-hardened member made of titanium and a titanium alloy is characterized in that 2 to 6.0% by weight of nitrogen is contained in a solid solution state without forming a compound.

As a result of a detailed study of the configuration of a cured member having a surface-hardened layer while maintaining the surface state, the following was found. In other words, in order to increase the hardness of the surface while maintaining the surface state before the treatment without causing surface roughness, the hardened layer must be formed in a state where nitrogen forms a solid solution without forming a compound. It is. It is not preferable that nitrogen is contained in the cured layer in a state where a compound is formed, since a colored substance is formed on the surface to deteriorate the appearance quality.
In addition, since the formation of the compound forms a cured layer having an interface on the cured member and causes problems such as peeling, the cured layer is formed in a state where nitrogen forms a solid solution without forming the compound. It is necessary to be. By forming a hardened layer having a thickness of 5 μm or more in which nitrogen is dissolved as described above, a colored substance such as titanium nitride is formed on the surface while maintaining the surface state before the treatment without causing surface roughness. Vickers hardness of the surface is Hv =
It has been found that a surface hardness of 450 or more is achieved. In such a configuration, as a result of various studies on the amount and thickness of nitrogen to be dissolved in the member, a depth of 5
It has been found that it is necessary to form a surface-hardened layer in which 0.2 to 6.0% by weight of nitrogen is dissolved as a solid solution in the area of μm or more.

[0008] As a result of various investigations on the hardening method of a hardened member having a surface hardened layer while maintaining the surface condition before the processing, the following hardening method was used to obtain the surface and the inside of the member made of titanium and titanium alloy. Has been found to be capable of being cured. That is, after the inside of the vacuum chamber in which the heating means, the tray, and the member made of titanium and titanium alloy were arranged was evacuated to a pressure at which the influence of the residual gas could be eliminated, helium or argon was introduced into the vacuum chamber. A heating step of heating a member made of titanium and a titanium alloy placed on a tray in a reduced-pressure atmosphere to 700 to 800 ° C. for a predetermined time by a heating means to perform an annealing treatment, and in a reduced-pressure atmosphere in which a gas containing a nitrogen component is introduced. A curing treatment step of maintaining nitrogen at the same temperature as the heating step for a predetermined time and diffusing nitrogen from the surface of the cured member to the inside to form a solid solution and form a cured layer in which nitrogen is dissolved without forming a nitrogen compound, After stopping the supply of the gas containing gas and evacuating it to a vacuum, place it at the same temperature as the curing process in a reduced pressure atmosphere in which helium or argon is introduced. After the retention time, it is possible to cure the treated surface of the member and the interior and then cooled to room temperature to stop heating.

In the present invention, a curing method for curing a member made of titanium and a titanium alloy includes a heating step of heating a decorative member to 700 to 800 ° C. for a predetermined time by a heating means and performing an annealing treatment; In a reduced pressure atmosphere introduced into the vacuum chamber, the same temperature as the heating step is maintained for a predetermined time, nitrogen is diffused from the surface of the member made of titanium and the titanium alloy into the inside, a hardening process of forming a hardened layer by forming a solid solution, A cooling step of cooling to a normal temperature in a helium or argon atmosphere.

A member made of titanium and a titanium alloy is
The heating step of heating to 00 to 800 ° C. and annealing is performed for the purpose of relaxing a work strain layer generated when a member made of titanium and a titanium alloy is worked by polishing after hot forging. . The work-strained layer is a crystalline amorphous phase in a state where the stress at the time of polishing remains as a lattice strain. When the hardening treatment is performed on the member made of titanium and titanium alloy after the polishing processing without performing the annealing treatment, the diffusion by thermal diffusion of nitrogen and the solid solution are performed while relaxing the work strain layer.
At the outermost surface of a member made of titanium and a titanium alloy, the reaction amount of nitrogen is higher, and the amount reacted in the outermost surface layer is larger than the amount diffused and dissolved in the inside, and as a result, a colored substance is formed on the outermost surface. Certain nitrides are formed. When this colored substance is formed, the appearance quality is deteriorated, so that it is not a preferable state as a cured member. Therefore, a member made of polished titanium and a titanium alloy needs to be subjected to a heating step before the hardening step in the present invention.

The curing step is characterized in that the same heating state as in the heating step is maintained for a predetermined time in an atmosphere in which a gas containing a nitrogen component is introduced into the vacuum chamber immediately after the heating step is completed.

[0012] Fig. 1 shows a second type of titanium material having a mirror-finished appearance defined by JIS standard after curing for 7 hours in a nitrogen gas atmosphere by changing the processing temperature to 690-810 ° C. The result of measuring Vickers hardness is shown. If the processing temperature is 690 ° C. or lower, the Vickers hardness becomes Hv = 450 or lower, and a sufficient curing process cannot be performed. This is because at a temperature of 690 ° C. or lower, nitrogen does not sufficiently diffuse and dissolve in a member made of titanium and a titanium alloy, so that a hardened layer is not formed and the surface hardness does not increase. On the other hand, when the processing temperature is 810 ° C. or higher, the diffusion and dissolution rate of nitrogen are large in a member made of titanium and a titanium alloy, and a thick hardened layer is obtained, so that the Vickers hardness becomes Hv = 1050 or higher. , The crystal grains become coarse and surface roughness occurs, and the surface state before the treatment cannot be maintained.

FIG. 2 (a) shows the surface of a titanium type 2 material defined by the JIS standard having a mirror surface appearance as an X-ray incident angle α.
= 0.5 ° shows the result of analysis by thin film X-ray diffraction.
Similarly, FIG. 2 (b) shows the treatment of a titanium second material in a nitrogen gas atmosphere at 800 ° C., and FIG. 2 (c) shows the treatment of a titanium second material in a nitrogen gas atmosphere at 810 ° C. for 10 hours. The result of having analyzed the surface after processing by the thin film X-ray diffraction is shown. The peak at the treatment temperature of 800 ° C. shows a peak almost equivalent to that of the second kind of titanium, and no nitrogen compound such as titanium nitride which is a coloring substance is formed on the surface. The surface is also uncolored by visual inspection. On the other hand, at the processing temperature of 810 ° C., unlike the peak of titanium
A clear peak was observed at 36.7 ° and 42.6 ° in Θ, which coincides with the peak of titanium nitride as a coloring substance. It is clear from the visual inspection that the surface is colored yellow, indicating that titanium nitride is formed on the surface. Therefore, when the treatment temperature is 810 ° C. or more, the supply amount of nitrogen to the surface becomes excessive and titanium nitride as a coloring substance is formed to deteriorate the appearance quality, so that application to a hardened member is difficult.

For the above reasons, in the present invention, the treatment temperature in the curing treatment step needs to be in the range of 700 to 800.degree. In order to harden the surface and inside of the member made of titanium and titanium alloy while maintaining the surface state before the treatment, it is necessary to prevent surface roughness and to form a compound by nitrogen near the surface of the member. The hardened layer is formed in a solid solution state. By forming a cured layer having such a configuration, a surface hardening treatment can be performed while maintaining the surface state before the treatment without causing surface roughness.

As the gas containing a nitrogen component, nitrogen gas or ammonia gas can be used, but a gas obtained by mixing helium or argon with nitrogen gas or ammonia gas may be used. What is important is that nitrogen diffuses and forms a solid solution from a surface of a member made of titanium and a titanium alloy without forming a nitrogen compound such as titanium nitride.

In the cooling step, the member made of titanium and titanium alloy after the hardening treatment step is cooled to room temperature quickly without taking out a nitrogen compound such as titanium nitride which is a coloring substance, and is taken out of the vacuum chamber. It is a process. In the cooling step, after the completion of the curing step, the supply of the gas containing the nitrogen component is stopped, the gas is evacuated, and then maintained at the same temperature as the curing step for a predetermined time in a reduced pressure atmosphere in which helium or argon is introduced, and then cooled to room temperature. It is characterized by: If the cooling step is the same gas atmosphere as the hardening step, the nitrogen is supplied while cooling, so it continues to be adsorbed even after nitrogen is no longer diffused from the surface of the member made of titanium or titanium alloy, Nitrogen is supplied excessively, and a nitrogen compound such as titanium nitride, which is a coloring matter, is formed on the surface. In order to prevent the formation of a nitrogen compound such as titanium nitride as the coloring substance, the atmosphere in the cooling step needs to be a helium or argon atmosphere. It is important that the cooling process does not use a gas atmosphere containing a nitrogen component.

In the present invention, a hardened member made of titanium and a titanium alloy is a hardened member whose surface and inside are hardened, and is made of a watch case, a watch band, a pierced earring, an earring, a ring, a spectacle frame made of titanium or a titanium alloy. In addition to decorative articles such as rubber, any other applicable material can be used as long as the member can be cured until the surface state before the treatment is maintained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The object of the present invention is to carry out a hardening treatment of a member made of titanium and a titanium alloy without any coloring on the surface and without fear of peeling, while maintaining the surface state before the treatment. For this purpose, a heating means, a tray, and a member made of titanium and a titanium alloy are arranged in a vacuum chamber having a gas inlet and a gas exhaust port, and after evacuation with high vacuum, a vacuum atmosphere or helium or argon is used. Heating a member placed on a tray in a reduced-pressure atmosphere introduced into the vacuum chamber by heating means to a temperature of 700 to 800 ° C. for a predetermined time to perform a refining process, and supplying a gas containing a nitrogen component to the inside of the vacuum chamber. A hardening treatment step of maintaining nitrogen at the same temperature as the heating step for a predetermined time in a reduced pressure atmosphere introduced into the member, diffusing nitrogen from the surface of the member to the inside to form a hardened layer, and forming a hardened layer. By taking the curing process wherein it comprising the step of cooling to room temperature at a reduced pressure atmosphere obtained by introducing Gon, over a depth 5μm from the surface 0.2
A surface hardened layer in which up to 6.0% by weight of nitrogen forms a solid solution is formed, and the object is achieved.

[0019]

【Example】

(Embodiment 1) A first embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic view showing an apparatus configuration for hardening a member made of titanium and a titanium alloy.
FIG. 3 is a schematic cross-sectional view showing the structure of a member that has been cured.
Inside a vacuum chamber 6 having a gas inlet 10 and a gas exhaust port 14, a member 2 made of titanium and a titanium alloy and a member 2 made of titanium and a titanium alloy are heated on a tray 4 serving as a substrate support. A heater 8 is provided as a heating means for activating the heater. By the vacuum pump 16 through the gas outlet 14 inside the vacuum chamber 6, 1 × 10 influence of the residual gas atmosphere is eliminated ^- titanium by motor 8 and the titanium alloy - ⁵ Torr heat after evacuated to a pressure of less than Member 2 to 690-810 ° C for 30
After heating and annealing for one minute, the gas introduction valve 12 of the gas introduction port 10 is opened and nitrogen gas is introduced to reduce the pressure to 0.3 Torr.
A member made of titanium and a titanium alloy by adsorbing and diffusing nitrogen 20 on the surface of the member 2 made of titanium and a titanium alloy while maintaining the temperature at the time of annealing treatment in an atmosphere adjusted to a constant value for 7 hours. Nitrogen 20 was diffused from the surface of No. 2 to the inside to form a solid solution to form a hardened surface layer 18.
Thereafter, the gas introduction valve 12 of the gas introduction port 10 is closed, and the inside of the vacuum chamber 6 is evacuated to a pressure of 1 × 10 ⁻³ Torr or less by the vacuum pump 16 through the gas exhaust port 14. The gas introduction valve 12 is opened, helium is introduced, and the temperature is kept constant for 30 minutes while maintaining the temperature at which the curing process is performed in an atmosphere adjusted to a pressure of 0.3 Torr. Then, the heating by the heater 8 is stopped and the helium is stopped. It was cooled to room temperature in an atmosphere.

The member to be cured has a mirror-finished J
Clock case made of titanium second class material defined by IS standard
The treatment was performed by changing the treatment temperature in the above temperature range of 690 to 810 ° C. Thereafter, the hardness, the diffusion depth and concentration of nitrogen, the surface roughness, the size of the crystal grains of the surface texture, and the presence or absence of titanium nitride as a coloring substance were measured and evaluated. The hardness was measured with a Vickers hardness tester, and those having a load of 50 gf and a surface hardness of Hv = 450 or more were accepted. The diffusion depth and concentration of nitrogen can be measured using a secondary ion mass spectrometer (SIM).
S), and 0.2 at a depth of 5 μm or more from the surface.
Those containing ６6.0% by weight of nitrogen were accepted. These results are shown in FIG. 5, FIG. 6, FIG. 7, and Table 1. As for the surface roughness, the average surface roughness Ra was measured using a surface roughness meter, and those having a surface roughness of 0.4 μm or less were accepted. The size of the crystal grain Rc is determined by measuring the crystal structure of the surface with an electron microscope.
Those within the range of 0 to 65 µm were regarded as acceptable. The presence or absence of the coloring substance, titanium nitride, was measured by thin-film X-ray diffraction at an X-ray incidence angle α = 0.5 °, and those having no peak of titanium nitride were accepted. Table 1 shows the measurement results.

[0021]

[Table 1]

Sample numbers a to d are each processed by changing the processing temperature from 690 ° C. to 810 ° C., and sample number e is an untreated titanium second class material.

As is clear from Table 1, in sample No. a (processing temperature: 690 ° C.), both the average surface roughness Ra after the treatment and the crystal grain size Rc after the treatment are the same as those of the sample No. e. The appearance quality is as good as the seed material, but the surface hardness is as low as Hv = 340, 0.2-6.0% by weight
Since the nitrogen content depth of 2.1 μm was 2.1 μm, a cured layer having a sufficient thickness was not formed. FIG. 5 shows the results of measuring the diffusion depth and concentration of nitrogen in sample number a using a secondary ion mass spectrometer (SIMS). Sample number d
(The processing temperature is 810 ° C.), the surface hardness is Hv = 1050
And a cured layer having a sufficient thickness is formed since the nitrogen content of 0.2 to 6.0% by weight is 11.4 μm, but the average surface roughness after the treatment is Ra. =
As large as 1.0 μm, the crystal grains after treatment are also Rc = 70 to 2
The surface was coarsened to 20 μm, the surface roughness after the treatment was remarkably observed, and the curing treatment maintaining the surface state before the treatment was not performed. Since a peak of titanium nitride is clearly observed on the surface after the treatment, a hardened layer in a state where nitrogen is dissolved is not formed. On the other hand, in sample number b (processing temperature 700 ° C.), the hardness at the surface was as high as Hv = 500, and the nitrogen content depth of 0.2 to 6.0% by weight was 5.2 μm.
m, a cured layer having a sufficient thickness is formed. FIG. 6 shows the results of measuring the diffusion depth and concentration of nitrogen in sample number b using a secondary ion mass spectrometer (SIMS). Average surface roughness after treatment is Ra = 0.25μ
m, the crystal grains after the treatment are also Rc = 30 to 50 μm, hardly changing compared to the untreated titanium second material of sample number e, and the hardening treatment is performed while maintaining the surface state before the treatment. . Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. Similarly, in sample number c (processing temperature 800 ° C.), the hardness on the surface is as high as Hv = 900, and the nitrogen-containing depth of 0.2 to 6.0% by weight is 9.9 μm, so that a sufficient thickness is obtained. Is formed. FIG. 7 shows the results of measuring the diffusion depth and concentration of nitrogen in sample number b using a secondary ion mass spectrometer (SIMS). The average surface roughness after the treatment is Ra = 0.35 μm, and the crystal grains after the treatment are also R
c = 30 to 60 μm and untreated titanium second sample number e
The hardening treatment has been performed with little change compared to the seed material and the surface condition before the treatment maintained. Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. As described above, the sample numbers b and c are 0.2 to 6.0% by weight at a depth of 5 μm or more from the surface.
It is clear that a hardened layer containing nitrogen as a solid solution without forming a compound such as titanium nitride is formed, and a sufficient hardened surface layer containing a limited amount of nitrogen in the present invention is formed. It was recognized that it had.

(Embodiment 2) A second embodiment of the present invention will be described as a first embodiment.
A description will be given with reference to FIGS. FIG. 3 is a schematic diagram showing an apparatus configuration for hardening a member made of titanium and a titanium alloy, and FIG. 4 is a schematic cross-sectional view showing the structure of the hardened member. Inside a vacuum chamber 6 having a gas inlet 10 and a gas exhaust port 14, a member 2 made of titanium and a titanium alloy and a member 2 made of titanium and a titanium alloy are heated on a tray 4 serving as a substrate support. A heater 8 is provided as a heating means for activating the heater. By the vacuum pump 16 through the gas outlet 14 inside the vacuum chamber 6, 1 × 10 influence of the residual gas atmosphere is eliminated ^- was evacuated to ⁵ Torr or less pressure, the gas inlet valve 12 of the gas inlet 10 Open helium was introduced, the pressure was adjusted to 0.5 Torr, and the member 2 made of titanium and a titanium alloy was heated to 690 to 8 by a heater-8.
After heating to 10 ° C. for 30 minutes for annealing, the gas inlet valve 12 of the gas inlet 10 is closed, and the inside of the vacuum chamber 6 is reduced to 1 × 10 ⁻³ by the vacuum pump 16 through the gas outlet 14.
After evacuating to a pressure equal to or lower than Torr, the gas inlet valve 12 of the gas inlet 10 is opened, a gas obtained by mixing nitrogen gas with helium is introduced, and annealing is performed in an atmosphere where the pressure is adjusted to 0.5 Torr. While keeping the temperature constant for 7 hours, nitrogen 20 is adsorbed and diffused on the surface of the member 2 made of titanium and titanium alloy, and the nitrogen 20 is diffused from the surface of the member 2 made of titanium and titanium alloy to the inside. A solid solution was formed to form a surface hardened layer 18. After that, the gas introduction valve 12 of the gas introduction port 10 is closed, and the inside of the vacuum chamber 6 is
-After evacuating to a pressure of ^-3 Torr or less, open the gas introduction valve 12 of the gas introduction port 10, introduce helium, and maintain the temperature at the time of curing treatment in an atmosphere adjusted to 0.5 Torr for 30 minutes while maintaining the temperature. After keeping the temperature constant, the heating by the heater 8 was stopped, and the mixture was cooled to room temperature in a helium atmosphere.

In the second embodiment, a watch case made of a titanium second-class material defined by JIS standards having a mirror-finished appearance as in the first embodiment is completely the same as the first embodiment. After treatment under various temperature conditions, as in Example 1,
The hardness, the diffusion depth and concentration of nitrogen, the surface roughness, the size of crystal grains in the surface texture, and the presence or absence of a nitrogen compound as a coloring substance were measured. Table 2 shows the measurement results.

[0026]

[Table 2]

Sample numbers f to i were obtained by changing the processing temperature from 690 ° C. to 810 ° C., respectively, and sample number e was untreated titanium second-class material.

As is clear from Table 2, in sample number f (treatment temperature: 690 ° C.), both the average surface roughness Ra after the treatment and the crystal grain size Rc after the treatment correspond to the untreated titanium second sample number e. The appearance quality is as good as the seed material, but the surface hardness is as low as Hv = 390, 0.2-6.0% by weight
Since the nitrogen content depth of the sample was 2.0 μm, a cured layer having a sufficient thickness was not formed. In sample number i (processing temperature of 810 ° C.), the hardness of the surface was as high as Hv = 1030, and the nitrogen content depth of 0.2 to 6.0% by weight was 1
Although the cured layer having a sufficient thickness was formed because of the 1.4 μm, the average surface roughness after the treatment was Ra = 1.
0 μm and Rc = 70-220 after treatment
The surface was coarsened to μm, and the surface roughness after the treatment was remarkably observed, and the hardening treatment maintaining the surface state before the treatment was not performed. Since a peak of titanium nitride is clearly observed on the surface after the treatment, a hardened layer in a state where nitrogen is dissolved is not formed. Sample number g (processing temperature 70
0 ° C), the hardness on the surface is as high as Hv = 480,
Since the content depth of nitrogen of 0.2 to 6.0% by weight is 5.1 μm, a cured layer having a sufficient thickness is formed. The average surface roughness after the treatment is Ra = 0.25 μm, and the crystal grains after the treatment are Rc = 30 to 50 μm, and there is almost no change as compared with the untreated titanium second material of sample number e. The hardening process is performed while maintaining the state. Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. Similarly, in sample number h (processing temperature 800 ° C.), the hardness on the surface is as high as Hv = 880, and the nitrogen-containing depth of 0.2 to 6.0% by weight is 9.8 μm, so that a sufficient thickness is obtained. Is formed. The average surface roughness after the treatment is Ra = 0.35 μm, and the crystal grains after the treatment are also Rc = 35 to
The hardening treatment is performed with almost no change as compared with the untreated titanium second material of 60 μm and the sample number e, and the surface state before the treatment is maintained. Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. As described above, sample numbers g and h have a cured layer containing 0.2 to 6.0% by weight of nitrogen at a depth of 5 μm or more from the surface in a solid solution state without forming a compound such as titanium nitride. It was clear that the layer had been formed, and it was confirmed that the layer contained a limited amount of nitrogen in the present invention and had a sufficient surface hardened layer.

(Embodiment 3) A third embodiment of the present invention will be described as a first embodiment.
A description will be given with reference to FIGS. FIG. 3 is a schematic diagram showing an apparatus configuration for hardening a member made of titanium and a titanium alloy, and FIG. 4 is a schematic cross-sectional view showing the structure of the hardened member. Inside a vacuum chamber 6 having a gas inlet 10 and a gas exhaust port 14, a member 2 made of titanium and a titanium alloy and a member 2 made of titanium and a titanium alloy are heated on a tray 4 serving as a substrate support. A heater 8 is provided as a heating means for activating the heater. By the vacuum pump 16 through the gas outlet 14 inside the vacuum chamber 6, 1 × 10 influence of the residual gas atmosphere is eliminated ^- was evacuated to ⁵ Torr or less pressure, the gas inlet valve 12 of the gas inlet 10 Open helium was introduced, the pressure was adjusted to 0.01 Torr, and the member 2 made of titanium and a titanium alloy was heated to 690 to 690 by a heater-8.
After heating to 810 ° C. for 30 minutes for annealing, the gas inlet valve 12 of the gas inlet 10 is closed, and the inside of the vacuum chamber 6 is
^After evacuating to a pressure of ⁻³ Torr or less, open the gas introduction valve 12 of the gas introduction port 10 and introduce a gas obtained by mixing helium with ammonia gas to reduce the pressure to 0.01 Torr.
A member made of titanium and a titanium alloy by adsorbing and diffusing nitrogen 20 on the surface of the member 2 made of titanium and a titanium alloy while maintaining the temperature at the time of the annealing treatment in the atmosphere adjusted to 5 hours, Nitrogen 20 was diffused from the surface of No. 2 to the inside to form a solid solution to form a hardened surface layer 18.
Thereafter, the gas introduction valve 12 of the gas introduction port 10 is closed, and the inside of the vacuum chamber 6 is evacuated to a pressure of 1 × 10 ⁻³ Torr or less by the vacuum pump 16 through the gas exhaust port 14. The gas introduction valve 12 is opened, helium is introduced, and the temperature is kept constant for 30 minutes while maintaining the temperature at which the curing process is performed in an atmosphere adjusted to 0.1 Torr. Then, the heating by the heater 8 is stopped and the helium is stopped. It was cooled to room temperature in an atmosphere.

Also in the third embodiment, the member to be cured has a JIS having a mirror-like appearance as in the first and second embodiments.
A watch case made of the second class titanium material defined in the standard was treated under the same temperature conditions as in the first and second embodiments, and then the hardness and the nitrogen were measured in the same manner as in the first and second embodiments. Was measured for the diffusion depth and concentration, the surface roughness, the size of crystal grains in the surface texture, and the presence or absence of a nitrogen compound as a coloring substance. Table 3 shows the measurement results.

[0031]

[Table 3]

Sample numbers j to m are each processed by changing the processing temperature from 690 ° C. to 810 ° C., and sample number e is an untreated titanium second class material.

As is clear from Table 3, in sample number j (processing temperature: 690 ° C.), both the average surface roughness Ra after the treatment and the crystal grain size Rc after the treatment correspond to the untreated titanium second sample of the sample number e. The appearance quality is as good as the seed material, but the surface hardness is as low as Hv = 390, 0.2-6.0% by weight
Since the nitrogen containing depth was 2.5 μm, a cured layer having a sufficient thickness was not formed. In sample number m (processing temperature: 810 ° C.), the surface hardness was as high as Hv = 1100, and the nitrogen content depth of 0.2 to 6.0% by weight was 1
Although the cured layer having a sufficient thickness is formed because the average surface roughness is 2.0 μm, the average surface roughness after the treatment is Ra = 1.
0 μm, and the crystal grains after treatment are also Rc = 70 to 250
The surface was coarsened to μm, and the surface roughness after the treatment was remarkably observed, and the hardening treatment maintaining the surface state before the treatment was not performed. Since a peak of titanium nitride is clearly observed on the surface after the treatment, a hardened layer in a state where nitrogen is dissolved is not formed. Sample number k (processing temperature 70
0 ° C), the hardness on the surface is as high as Hv = 550,
Since the content depth of nitrogen of 0.2 to 6.0% by weight is 5.5 μm, a cured layer having a sufficient thickness is formed. The average surface roughness after the treatment is Ra = 0.25 μm, and the crystal grains after the treatment are Rc = 30 to 50 μm, and there is almost no change as compared with the untreated titanium second material of sample number e. The hardening process is performed while maintaining the state. Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. Similarly, in sample No. 1 (processing temperature 800 ° C.), the hardness on the surface is as high as Hv = 960, and the depth of nitrogen content of 0.2 to 6.0% by weight is 11.2 μm. Is formed. The average surface roughness after the treatment is Ra = 0.35 μm, and the crystal grains after the treatment are also Rc = 35.
The hardening treatment is performed with almost no change compared to the untreated titanium second material of the sample number e of μ60 μm and the surface state before the treatment is maintained. Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. As described above, Sample Nos. K and 1 have a cured layer containing 0.2 to 6.0% by weight of nitrogen at a depth of 5 μm or more from the surface in a solid solution state without forming a compound such as titanium nitride. It was clear that the layer had been formed, and it was confirmed that the layer contained a limited amount of nitrogen in the present invention and had a sufficient surface hardened layer.

(Embodiment 4) A fourth embodiment of the present invention will be described as a first embodiment.
A description will be given with reference to FIGS. FIG. 3 is a schematic diagram showing an apparatus configuration for hardening a member made of titanium and a titanium alloy, and FIG. 4 is a schematic cross-sectional view showing the structure of the hardened member. Inside a vacuum chamber 6 having a gas inlet 10 and a gas exhaust port 14, a member 2 made of titanium and a titanium alloy and a member 2 made of titanium and a titanium alloy are heated on a tray 4 serving as a substrate support. A heater 8 is provided as a heating means for activating the heater. By the vacuum pump 16 through the gas outlet 14 inside the vacuum chamber 6, 1 × influence of the residual gas atmosphere is eliminated 10 ^{- 5} Torr was evacuated to a pressure of less than, heat - titanium by motor 8 and titanium alloys Is heated to 690 to 810 ° C. for 30 minutes to perform an annealing treatment, and then the gas introduction valve 12 of the gas introduction port 10 is opened to introduce a gas in which ammonia gas is mixed with nitrogen gas, and the pressure is reduced to 5.
While maintaining the temperature at the time of annealing treatment in an atmosphere adjusted to × 10 ⁻³ Torr, the temperature was kept constant for 5 hours to adsorb and diffuse nitrogen 20 on the surface of the member 2 made of titanium and a titanium alloy. Nitrogen 20 was diffused from the surface of the member 2 made of a titanium alloy to the inside to form a solid solution to form a hardened surface layer 18. Thereafter, the gas inlet valve 12 of the gas inlet 10 is closed, and the vacuum pump 16
After evacuating the inside of the vacuum chamber 6 to a pressure of 1 × 10 ⁻³ Torr or less, the gas introduction valve 12 of the gas introduction port 10 is opened, helium is introduced, and curing is performed in an atmosphere where the pressure is adjusted to 0.1 Torr. Keep the temperature at the time of treatment 3
After the temperature was kept constant for 0 minutes, the heating by the heater 8 was stopped and the system was cooled to room temperature in a helium atmosphere.

In the fourth embodiment, as in the first, second and third embodiments, the member to be cured is a watch case made of a titanium second-class material defined by JIS having a mirror-like appearance. After the heat treatment was performed under exactly the same temperature conditions as those of Examples 1, 2, and 3, Examples 1, 2, and 3 were performed.
In the same manner as in the above, the hardness, diffusion depth and concentration of nitrogen, surface roughness, the size of crystal grains in the surface texture, and the presence or absence of a nitrogen compound as a coloring substance were measured. Table 4 shows the measurement results.

[0036]

[Table 4]

Each of the sample numbers n to q was processed by changing the processing temperature from 690 ° C. to 810 ° C., and the sample number e was an untreated titanium second class material.

As is apparent from Table 4, in the sample number n (treatment temperature: 690 ° C.), both the average surface roughness Ra after the treatment and the crystal grain size Rc after the treatment correspond to the untreated titanium second sample No. e. The appearance quality is as good as the seed material, but the surface hardness is as low as Hv = 380, 0.2 to 6.0% by weight.
Since the nitrogen containing depth was 2.5 μm, a cured layer having a sufficient thickness was not formed. In sample number q (processing temperature 810 ° C.), the surface hardness was as high as Hv = 1120, and the nitrogen content depth of 0.2 to 6.0% by weight was 1
The cured layer having a sufficient thickness was formed because the average surface roughness was Ra = 1.
0 μm and Rc = 80 to 250
The surface was coarsened to μm, and the surface roughness after the treatment was remarkably observed, and the hardening treatment maintaining the surface state before the treatment was not performed. Since a peak of titanium nitride is clearly observed on the surface after the treatment, a hardened layer in a state where nitrogen is dissolved is not formed. The sample number o (processing temperature 70
0 ° C), the hardness on the surface is as high as Hv = 560,
Since the content depth of nitrogen of 0.2 to 6.0% by weight is 5.5 μm, a cured layer having a sufficient thickness is formed. The average surface roughness after the treatment is Ra = 0.25 μm, and the crystal grains after the treatment are Rc = 30 to 50 μm, and there is almost no change as compared with the untreated titanium second material of sample number e. The hardening process is performed while maintaining the state. Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. Similarly, in sample number p (processing temperature 800 ° C.), the hardness on the surface is as high as Hv = 980, and the nitrogen-containing depth of 0.2 to 6.0% by weight is 12.1 μm, so that a sufficient thickness is obtained. Is formed. The average surface roughness after the treatment is Ra = 0.35 μm, and the crystal grains after the treatment are also Rc = 35.
The hardening treatment is performed with almost no change compared to the untreated titanium second material of the sample number e of μ60 μm and the surface state before the treatment is maintained. Further, since no peak of titanium nitride is observed on the surface after the treatment, it is clear that the hardened layer is formed in a state where nitrogen forms a solid solution without forming titanium nitride. As described above, Sample Nos. O and p have a hardened layer containing 0.2 to 6.0% by weight of nitrogen at a depth of 5 μm or more from the surface in a solid solution state without forming a compound such as titanium nitride. It was clear that the layer had been formed, and it was confirmed that the layer contained a limited amount of nitrogen in the present invention and had a sufficient surface hardened layer.

From the results of Example 1, Example 2, Example 3, and Example 4, the member made of titanium and the titanium alloy was heated by heating means in a vacuum atmosphere or a reduced pressure atmosphere into which helium or argon was introduced. ~ 800
° C for a predetermined time and an annealing treatment, and a gas containing a nitrogen component is held for a predetermined time at the same temperature as that of the heating step in a reduced-pressure atmosphere in which a gas containing nitrogen is introduced into the vacuum chamber. Titanium and titanium alloys by passing through three steps: a hardening treatment step of diffusing and dissolving nitrogen by thermal diffusion to form a hardened layer to form a hardened layer; and a cooling step of cooling to room temperature in a reduced pressure atmosphere containing helium or argon. It has become possible to form a hardened layer in a state in which nitrogen forms a solid solution without forming a compound while the surface of the member made of is maintained in the surface state before the treatment. It was also found that the thickness of the surface hardened layer and the prevention of surface roughness were controlled by the temperature of the gas atmosphere. The higher the treatment temperature, the higher the diffusion rate of nitrogen and the deeper the hardened layer is obtained. On the other hand, the crystal grains are coarsened and the surface is roughened. Since the appearance quality is degraded by reacting and forming a nitrogen compound such as titanium nitride which is a coloring substance, the processing temperature needs to be 800 ° C. or lower where crystal grains are not coarsened and a nitrogen compound such as titanium nitride is not formed. is there. On the other hand, at a processing temperature of 690 ° C. or lower, a temperature of 700 ° C. or higher is necessary because nitrogen does not form a solid solution and the surface hardness does not increase.

In the embodiments of the present invention, the watch case was used as the member to be hardened in each of the first, second, third and fourth embodiments. Not only watch cases but also those whose surfaces and inside are hardened and which are made of titanium and titanium alloy, watch accessories, watch bands, piercings, earrings, rings, eyeglass frames, etc. As long as the member can be cured until the surface state before the treatment is maintained, it is not limited to the decorative article, but means any applicable one.

[0041] In the heating step of the embodiment of the present invention, 1 × 10 Example 1 ^- in a vacuum atmosphere evacuated to a pressure of less than ⁵ Torr, Example 2, 1 × 10 ^{- 5} Tor
helium was introduced after evacuation to a pressure of
In Example 3 in an atmosphere adjusted to Torr pressure, 1
× 10 ^- up to ⁵ Torr or less pressure in an atmosphere adjusted to a pressure of 0.01Torr introducing helium after evacuation, Example 4, 1 × 10 ^- heating in a vacuum atmosphere evacuated to a pressure of less than ⁵ Torr The annealing treatment is performed by heating from 700 to 800 ° C. for 30 minutes by means, but the annealing time is not limited to 30 minutes, and may be any time as long as it is 30 minutes or more and 2 hours or less. The annealing treatment in the heating step is performed for the purpose of relaxing the strained layer formed on the member made of titanium and titanium alloy by polishing after hot forging, and the annealing temperature is limited to 700 to 800 ° C. If the temperature is within the range of 550 to 800 ° C., the annealing process can be performed at any temperature. However, it is necessary to shift to the curing process immediately after the heating process is completed. It is preferable to make the temperature of the process the same. Therefore, the processing temperature in the heating step needs to be 700 to 800 ° C.

[0042] In the heating step of the embodiment of the present invention, Examples 1 and 3, 1 × 10 ^- in a vacuum atmosphere of ⁵ Torr or less of pressure, the helium was adjusted to a pressure of 0.5Torr Example 2 In the reduced pressure atmosphere, in Example 3, the pressure was set to 0.
Annealing is performed in a reduced pressure atmosphere of helium adjusted to a pressure of 01 Torr, but the pressure is not limited to a pressure within this range, and any pressure may be used as long as it is a reduced pressure atmosphere. Either a vacuum atmosphere or a reduced pressure atmosphere of helium may be used. It is safe to use argon instead of helium.

In the curing step of the embodiment of the present invention,
The treatment time of the curing process is adjusted to a predetermined pressure by introducing a gas containing a nitrogen component, and then, in Examples 1 and 2, the same temperature as that in the heating process is used for 7 hours, and in Example 3 In Example 4, the temperature was maintained at the same temperature as that of the heating step for 5 hours. However, if the processing time of the curing step was 1 hour or less, Vickers hardness Hv = 450 or more at the surface with a load of 50 gf could not be obtained. Further, when the processing time of the hardening step is 10 hours or more, the Vickers hardness of the surface is saturated.
Therefore, the treatment time of the curing treatment step may be any time within the range of 1 to 10 hours.

In the hardening process of the second embodiment of the present invention, nitrogen is dissolved in a member made of titanium and a titanium alloy without forming a nitrogen compound in a gas atmosphere in which nitrogen gas is mixed with helium. By this, it became possible to obtain a cured member having an uncolored surface hardened layer while maintaining the surface state before the treatment, but the atmosphere gas was not limited to a mixed gas of helium and nitrogen gas, and argon and nitrogen were used. A mixed gas of gases may be used.

In the hardening treatment step of the third embodiment of the present invention, nitrogen is dissolved in a member made of titanium and a titanium alloy in a gas atmosphere in which ammonia gas is mixed with helium without forming a nitrogen compound. This makes it possible to obtain a cured member having an uncolored surface cured layer while maintaining the surface state before the treatment, but the atmospheric gas is not limited to a mixed gas of helium and ammonia gas, but may be argon and ammonia. A mixed gas of gases may be used.

In the hardening treatment step of the fourth embodiment of the present invention, nitrogen is dissolved in a member made of titanium and a titanium alloy in a gas atmosphere in which ammonia gas is mixed with nitrogen gas without forming a nitrogen compound. By doing so, it became possible to obtain a cured member having an uncolored surface cured layer while maintaining the surface state before the treatment, but the atmosphere gas was not limited to a mixed gas of nitrogen gas and ammonia gas, but helium. Alternatively, a mixed gas to which argon is added may be used.

In the hardening process of the embodiment of the present invention, the embodiment 1 and the embodiment 2 are performed in a reduced pressure atmosphere in which the pressure is adjusted to 0.3 to 0.5 Torr by using nitrogen gas as the gas containing a nitrogen component. In Examples 3 and 4, ammonia gas was used as the gas containing the nitrogen component, and the pressure was 5 × 10 ^{−3 to} 0.0.
Although the curing treatment was performed in a reduced pressure atmosphere adjusted to 1 Torr, the pressure of the gas atmosphere does not need to be limited to a pressure within this range, and any pressure may be used as long as it is a reduced pressure atmosphere.

In the cooling step of the embodiment of the present invention, after the hardening step is completed in all of the first, second, third and fourth embodiments, the supply of the gas containing the nitrogen component is stopped and the evacuation is performed. After holding for 30 minutes at the same temperature as the curing process in the atmosphere in which helium was introduced, heating by the heater was stopped and the temperature was cooled to room temperature in the helium atmosphere, but the temperature was maintained for 30 minutes at the same temperature as the curing process. The reason for this is that when cooling is performed while supplying a gas containing a nitrogen component in the cooling step, nitrogen continues to be adsorbed on the surface even after the nitrogen does not diffuse thermally, resulting in excessive supply of nitrogen and nitrogen such as titanium nitride, which is a colored substance on the surface. This is because, in order to form a compound, the gas atmosphere containing a nitrogen component is switched from a gas atmosphere containing a nitrogen component to a helium or argon atmosphere before the heating by the heating means is stopped. The holding time at the same temperature as that of the curing step may be any time as long as it is 30 minutes or more. However, if the cooling step time is too long, the processing efficiency is reduced.
The time is preferably not more than the time. The important thing is that in the cooling process,
Cooling to room temperature as a helium or argon atmosphere without using a gas atmosphere containing a nitrogen component.

In the cooling step of the embodiment of the present invention, cooling was performed to room temperature in a reduced pressure atmosphere of 0.1 to 0.5 Torr in which helium was introduced in all of the first, second, third and fourth embodiments. However, the pressure of the helium atmosphere is 0.
The pressure is not limited to 1 to 0.5 Torr, but may be any pressure as long as it is a reduced pressure atmosphere.

The purpose of the present invention is to obtain a cured member having a cured layer in which nitrogen forms a solid solution without forming a compound such as titanium nitride while maintaining the surface state before the treatment. The treatment method is not limited to the above method, and plasma may be used. What is important is that the structure has a structure in which nitrogen is dissolved in a solid solution without substantially changing the average surface roughness before and after the treatment, and further without increasing the crystal grains.

In the present invention, titanium and a titanium alloy are used for the member to be hardened. Titanium means a metal member mainly composed of pure titanium. It refers to the second type, the third type of titanium, and the like. Further, a titanium alloy means a metal member obtained by adding aluminum, vanadium, iron, or the like to a metal mainly composed of pure titanium, and is a titanium member defined by the JIS standard.
Species, such as titanium 60E species. In addition, various titanium alloys and various titanium-based intermetallic compounds are included in the titanium alloy.

[0052]

As described above, according to the present invention, in a member made of titanium and a titanium alloy, surface hardening in which 0.2 to 6.0% by weight of nitrogen forms a solid solution at a depth of 5 μm or more from the surface. By forming the layer, the surface of the member made of titanium and a titanium alloy is not roughened, and the surface of the member and the inside of the member are maintained while maintaining the surface state before the treatment without forming a coloring substance on the surface. It has become possible to provide a hardened titanium hardened member which is hardened and hardly damaged, and a hardening method thereof. In addition, since the cured member obtained by the present invention maintains the surface state before the treatment even after the curing treatment, it has become possible to provide a cured member in a practical range with improved decorativeness.

[Brief description of the drawings]

FIG. 1 is a diagram showing a correlation between a processing temperature and Vickers hardness in the present invention.

FIG. 2 is a peak diagram by thin-film X-ray diffraction showing the processing temperature and the presence or absence of titanium nitride on the surface in the present invention.

FIG. 3 is a schematic diagram showing an apparatus configuration for describing a method of curing a cured member according to an embodiment of the present invention.

FIG. 4 is a schematic sectional view showing the structure of a cured member according to one embodiment of the present invention.

FIG. 5 shows the results of measuring the diffusion depth and concentration of nitrogen using a secondary ion mass spectrometer (SIMS) after curing a titanium second material according to an embodiment of the present invention at a processing temperature of 690 ° C. FIG.

FIG. 6 shows the results of measuring the diffusion depth and concentration of nitrogen using a secondary ion mass spectrometer (SIMS) after curing a titanium second material according to an embodiment of the present invention at a processing temperature of 700 ° C. FIG.

FIG. 7 shows the results of measuring the diffusion depth and concentration of nitrogen with a secondary ion mass spectrometer (SIMS) after curing a titanium second material according to an embodiment of the present invention at a processing temperature of 800 ° C. FIG.

[Description of Signs] 2 Curing member 4 Tray 6 Vacuum tank 8 Heater 10 Gas inlet 12 Gas inlet valve 14 Gas exhaust 16 Vacuum pump 18 Surface hardened layer 20 Nitrogen

Continued on the front page (51) Int.Cl. ⁶ Identification code FI C22F 1/00 691 C22F 1/00 691Z 691B 692 692Z 1/18 1/18 H

Claims (7)

[Claims] 1. A hardened titanium member having a hardened surface layer, wherein the hardened surface layer is formed at a depth of 5 μm or more from the surface and has a solid solution of 0.2 to 6.0% by weight of nitrogen. A hardened titanium member, characterized in that it is made of: 2. A heating means, a tray, and a member made of titanium and a titanium alloy are arranged in a vacuum chamber having a gas inlet and a gas exhaust port, and the inside of the vacuum chamber is evacuated. A heating step of heating the placed member made of titanium and titanium alloy by a heating means to 700 to 800 ° C. for a predetermined time and performing an annealing treatment; and a predetermined step at the same temperature as the heating step in a reduced-pressure atmosphere containing a gas containing a nitrogen component. A hardening process in which nitrogen is diffused and solid-dissolved from the surface of the member made of titanium and a titanium alloy to the inside to form a hardened layer in which nitrogen is solid-dissolved, and the supply of a gas containing a nitrogen component is stopped to evacuate. And a cooling step of maintaining the same temperature as the hardening treatment step for a predetermined time in a reduced pressure atmosphere in which helium or argon is introduced, and then cooling to room temperature. Titanium and hardening method of titanium curing member made of titanium alloy. 3. A vacuum chamber having a gas inlet and a gas exhaust port is provided with a heating means, a tray, and a member made of titanium or a titanium alloy. The inside of the vacuum chamber is evacuated, and then the pressure is reduced by introducing helium or argon. A heating step of heating a member made of titanium and a titanium alloy placed on a tray in an atmosphere to a temperature of 700 to 800 ° C. for a predetermined time by a heating means and performing an annealing treatment; and heating in a reduced-pressure atmosphere in which a gas containing a nitrogen component is introduced. A hardening treatment step in which nitrogen is diffused and solid-dissolved from the surface of the member made of titanium and titanium alloy to form a hardened layer in which nitrogen is solid-dissolved, and held at the same temperature as the process for a predetermined time; Stop supply, evacuate, hold in a reduced pressure atmosphere with helium or argon at the same temperature as the curing process for a predetermined time, then cool to room temperature Hardening a titanium curing member that consists of a cooling step consisting of titanium and titanium alloys, characterized in that. 4. The method according to claim 2, wherein the atmosphere of the hardening step is a nitrogen gas. 5. The hardening of a hardened titanium member made of titanium and a titanium alloy according to claim 2, wherein the atmosphere in the hardening step is a gas obtained by mixing helium or argon with nitrogen gas. Processing method. 6. The hardening of a hardened titanium member comprising titanium and a titanium alloy according to claim 2, wherein the atmosphere in the hardening step is a gas obtained by mixing helium or argon with ammonia gas. Processing method. 7. The hardening treatment of a titanium hardened member made of titanium and a titanium alloy according to claim 2, wherein the atmosphere of the hardening process is a gas obtained by mixing ammonia gas with nitrogen gas. Method.