JP2015181874A - Fastener component, metal powder for powder metallurgy, and method for manufacturing fastener component - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fastener component excellent in slidability and corrosion resistance, a metal powder for powder metallurgy with which the fastener component excellent in slidability and corrosion resistance can easily manufactured, and a method for manufacturing the fastener component.SOLUTION: A slide fastener 1 comprises: a pair of fastener tapes 11; a plurality of elements 12 equally spaced apart along the fastener tape 11; a first stopper 13 disposed at one end of the row of elements 12; a second stopper 14 disposed at the other end of the row of elements 12; a slider 15 slidable along the fastener tape 11. Any of these parts are composed of sintered body of metal powders, which contains Co as a principal components, in a proportion, Cr of 16 mass% or more and 35 mass% or less, Mo of 3 mass% or more and 12 mass% or less, Si of 0.3 mass% or more and 2.0 mass% or less, and N of 0.09 mass% or more and 0.5 mass% or less.

Description

  The present invention relates to a fastener part, a metal powder for powder metallurgy, and a method for producing a fastener part.

  The slide fastener is composed of fastener parts such as an element, a fastener, and a slider. Such a slide fastener is used for the purpose of connecting two pieces of cloth, for example. By operating the slider, the cloths can be connected to each other or disconnected. That is, the slide fastener can be opened and closed. In recent years, it is also used for the purpose of connecting fish farming nets. As a result, for example, it is possible to perform repairs such as replacing only the part where the net is broken, thereby facilitating work and reducing costs. In addition, slide fasteners are used in scuba diving suits, diving suits, and even space suits.

  As a constituent material of such fastener parts, for example, resin, brass, titanium alloy and the like are known.

  Among these, although the resin can be manufactured at a low cost, it has a problem of low durability against ultraviolet rays. For this reason, when used in the sea or in seawater, the fastener parts may be deteriorated and damaged, and the connected state of the slide fastener may not be maintained.

  Moreover, since brass has high slipperiness, smooth operation becomes possible. Furthermore, it has durability against ultraviolet rays. However, brass has a problem that it tends to corrode when exposed to seawater or the like for a long period of time. For this reason, long-term use in water is difficult.

  On the other hand, a titanium alloy has sufficient durability against ultraviolet rays, seawater, and the like, but has a problem of high surface frictional resistance. For this reason, frictional heat is generated in accordance with the opening / closing operation, and there is a problem that the slider and the element are easily fixed.

  Further, Patent Document 1 proposes that a lubrication layer is formed on the surface, thereby improving the lubricity of the surface of the member and suppressing deterioration of the material from, for example, water vapor. Specifically, Patent Document 1 proposes an automobile part having a lubricity layer made of DLC (Diamond Like Carbon) on the surface to improve the lubricity of the surface.

  However, when a lubrication layer is formed on the sliding surface, the lubrication layer may be peeled off with long-term sliding. When the lubricating layer is peeled off, the slider and the element may be fixed, or the material may be easily deteriorated.

JP-A-10-30679

  An object of the present invention is to provide a fastener part excellent in slipperiness and corrosion resistance, a metal powder for powder metallurgy that can easily produce a fastener part having high slipperiness and corrosion resistance, and a method for producing the fastener part. is there.

The above object is achieved by the present invention described below.
The fastener component of the present invention is mainly composed of Co,
Cr is contained in a proportion of 16% by mass to 35% by mass,
Mo is contained in a ratio of 3% by mass to 12% by mass,
Si is contained in a proportion of 0.3% by mass or more and 2.0% by mass or less,
N is included in a ratio of 0.09 mass% to 0.5 mass%,
It contains the site | part comprised by the sintered compact of metal powder, It is characterized by the above-mentioned.

  As a result, even when exposed to seawater or the like over a long period of time or exposed to ultraviolet rays, elution of constituent elements, deterioration of materials, and the like are unlikely to occur, so that a fastener component excellent in slipperiness and corrosion resistance can be obtained. As a result, for example, a highly reliable slide fastener that can be smoothly opened and closed over a long period of time even when used in seawater or at sea is obtained.

In the fastener part of the present invention, a part of the Si is included as silicon oxide,
The ratio of Si contained as the silicon oxide in the Si is preferably 20% by mass or more and 80% by mass or less.

  As a result, the fastener part is improved in mechanical properties, while a certain amount of silicon oxide is present. Therefore, the amount of oxide of transition metal elements such as Co, Cr, and Mo contained in the fastener part is reduced. A fastener component that can be sufficiently suppressed and has high reliability is obtained. In addition, on the surface of the fastener part, a certain amount of silicon oxide forms a chemically stable film together with chromium oxide and molybdenum oxide, so that the corrosion resistance of the fastener part can be further enhanced. Furthermore, the hardness and slipperiness of the fastener part can be increased, and the wear resistance can be improved.

  In the fastener part of the present invention, it is preferable that the silicon oxide is segregated at a grain boundary of the sintered body.

  As a result, enlargement of the metal crystal is more reliably suppressed, and a fastener part having more excellent mechanical characteristics can be obtained. In addition, the slipperiness of the fastener part can be further improved.

In the fastener component of the present invention, in the X-ray diffraction pattern obtained by the X-ray diffraction method using CuKα rays, the highest peak height is 1 among the peaks caused by Co identified based on the ICDD card. In this case, the ratio of the highest peak height among the peaks attributed to Co ₃ Mo identified based on the ICDD card is preferably 0.01 or more and 0.5 or less.

  Thereby, since high hardness and high slipperiness are given to fastener parts, useful fastener parts are obtained.

  In the fastener part of the present invention, the ratio of the N content rate (N / Si) to the Si content rate is preferably 0.1 or more and 0.8 or less in terms of mass ratio.

  Thereby, it is possible to achieve both high mechanical properties in the fastener part and high corrosion resistance on the surface of the fastener part.

  In the fastener part of the present invention, it is preferable that Ni is contained in a ratio of 0.3 mass% or more and 15 mass% or less.

  Thereby, the plastic workability of a sintered compact can be improved and the characteristic suitable for forging can be added with respect to a sintered compact.

In the fastener part of the present invention, it is preferable that Fe is contained in a ratio of 0.3 mass% to 6 mass%.
Thereby, elongation and flexibility (toughness) can be imparted to the sintered body.

In the fastener part of the present invention, it is preferable that Mn is contained in a proportion of 0.3% by mass or more and 3% by mass or less.
Thereby, elongation and flexibility (toughness) can be imparted to the sintered body.

The fastener component of the present invention preferably has a surface corrosion area ratio of 1% or less when subjected to a test for 24 hours in accordance with a salt spray test method defined in JIS Z 2371.
Thereby, the fastener component which can be used for a long time also in seawater is obtained.

  In the fastener part of the present invention, the Vickers hardness is preferably 200 or more and 480 or less.

  Thereby, the fastener component which has the outstanding abrasion resistance is obtained. Such fastener parts can be smoothly opened and closed over a long period of time.

The metal powder for powder metallurgy of the present invention is mainly composed of Co,
Cr is contained in a proportion of 16% by mass to 35% by mass,
Mo is contained in a ratio of 3% by mass to 12% by mass,
Si is contained in a proportion of 0.3% by mass or more and 2.0% by mass or less,
N is included in a ratio of 0.09 mass% to 0.5 mass%,
It is used for manufacturing fastener parts.

  Thereby, the metal powder for powder metallurgy which can manufacture easily the fastener components excellent in slipperiness and corrosion resistance is obtained.

The manufacturing method of the fastener component of the present invention includes Co as a main component, Cr is contained in a proportion of 16% by mass or more and 35% by mass or less, Mo is contained in a proportion of 3% by mass or more and 12% by mass or less, Si Is a metal powder injection molding composition comprising a metal powder in which N is contained in a proportion of 0.3 to 2.0% by mass and N is contained in a proportion of 0.09 to 0.5% by mass. Molding by the method to obtain a molded body,
Firing the molded body to obtain a sintered body;
It is characterized by having.

  Thereby, the fastener components excellent in slipperiness and corrosion resistance can be manufactured easily.

It is a top view which shows the slide fastener containing the element to which embodiment of the fastener components of this invention is applied, a fastener, a slider, and a handle. It is a perspective view which expands and shows the slide fastener shown in FIG. 1 partially. Each sample No. It is a graph which shows the relationship between N density | concentration and Vickers hardness in the test pieces of 46-52.

  Hereinafter, the manufacturing method of the fastener component of this invention, the metal powder for powder metallurgy, and a fastener component is demonstrated in detail based on suitable embodiment shown to an accompanying drawing.

[Fastener parts]
The embodiment of the fastener component of the present invention can be applied to a component component (fastener component) of a slide fastener such as an element, a stopper, a slider, and a handle. All of these fastener parts require excellent slipperiness and corrosion resistance. Therefore, by applying the present invention to these fastener parts, it is possible to realize a slide fastener that can be smoothly opened and closed over a long period even in a harsh environment.

Hereinafter, each component will be sequentially described.
FIG. 1 is a plan view showing a slide fastener including an element, a fastener, a slider, and a handle to which an embodiment of the fastener component of the present invention is applied. FIG. 2 is a partially enlarged perspective view of the slide fastener shown in FIG. In the following description, for convenience of explanation, the upper part in FIG. 1 is described as “upper” and the lower part in FIG. 1 is described as “lower”.

  A slide fastener 1 shown in FIG. 1 is disposed at one end of a pair of fastener tapes 11 each having a strip shape, a plurality of elements 12 arranged at equal intervals with respect to the long side of the fastener tape 11, and a row of the elements 12. The first stopper 13, the second stopper 14 disposed at the other end of the row of the elements 12, and the element 12 attached to the pair of fastener tapes 11 are configured to pass through the inside. And a slider 15 slidable along the long side. Hereinafter, the configuration of each unit will be further described in detail.

  The pair of fastener tapes 11 includes a fastener tape 111 and a fastener tape 112. Among these, the fastener tape 111 includes a strip-shaped thin strip portion 111a and a core portion 111b provided along one long side of the thin strip portion 111a. Similarly, the fastener tape 112 also includes a strip-shaped thin strip portion 112a and a core portion 112b provided along one long side of the thin strip portion 112a. The element 12, the first stopper 13 and the second stopper 14 described above are attached to the core portions 111b and 112b, respectively. Moreover, each core part 111b, 112b has bending rigidity larger than the thin strip part 111a, 112a. For this reason, when the slider 15 is slid along the row of the elements 12, the fastener tape 11 is not easily bent, and the slider 15 can be smoothly operated.

  As shown in FIG. 2, the element 12 includes a fixing portion 121 that can be fixed to the fastener tape 11, and a member that is provided at one end of the fixing portion 121 and that can engage with another element 12. And a joint portion 122. The fixing part 121 fixes the element 12 to the fastener tapes 111 and 112 by crimping the core parts 111 b and 112 b of the fastener tapes 111 and 112. Further, the engaging portion 122 can fix the elements 12 to each other by engaging with the engaging portions 122 of the other elements 12.

  Engagement between the engagement portions 122 is performed by passing the engagement portion 122 through the slider 15. In the slide fastener 1 shown in FIG. 1, below the slider 15, there are an engagement portion 122 of the element 12 attached to the fastener tape 111 and an engagement portion 122 of the element 12 attached to the fastener tape 112. Are engaged with each other and are in a closed state. On the other hand, above the slider 15, the engaging portions 122 are separated from each other and are in an open state.

  As shown in FIGS. 1 and 2, the first stopper 13 is configured to crimp both the core portion 111 b of the fastener tape 111 and the core portion 112 b of the fastener tape 112. Thereby, the end of the fastener tape 111 and the end of the fastener tape 112 can be maintained in a close proximity. Further, by attaching the first stopper 13, it is possible to prevent the slider 15 from dropping from the row of elements 12. In addition, the shape of the 1st fastener 13 is not limited to what was illustrated. For example, the shape of the first stopper 13 is the same as that of the second stopper 14 to be described later, and the shape can pass through the slider 15, so that the fastener tape 111 and the fastener tape 112 are opened in the open state. It can also be completely separated.

  As shown in FIGS. 1 and 2, the second stopper 14 is configured to crimp the cores 111 b and 112 b and is attached to the core 111 b of the fastener tape 111 and the core 112 b of the fastener tape 112. It has been. Further, by attaching the second stopper 14, it is possible to prevent the slider 15 from dropping from the row of the elements 12.

  The slider 15 includes a slider body 151 and a handle 152 attached to the slider body 151. The slider body 151 slides along the row of the elements 12, thereby engaging the engaging portions 122 of the elements 12 or separating the engaging portions 122 engaged with each other. Further, the handle 152 is a part that is held by the user of the slide fastener 1. By sliding the slider 15, the row of the elements 12 can be opened or closed. For example, in the case of the slide fastener 1 shown in FIG. 1, when the slider 15 is slid downward to the first stopper 13, all the elements 12 can be separated and the entire slide fastener 1 can be opened. On the other hand, when the slider 15 is slid upward to the second stopper 14, all the elements 12 are engaged with each other, and the entire slide fastener 1 can be closed.

  Note that the shape of the fastener component as described above is merely an example, and the embodiment of the fastener component of the present invention is not limited to the illustrated shape.

(Constituent materials)
Next, the constituent materials of the element 12, the first stopper 13, the second stopper 14, and the slider 15 of the slide fastener 1 described above will be described. In the following description, the element 12, the first stopper 13, the second stopper 14, and the slider 15 are collectively referred to as fastener parts.

  At least a part of the fastener parts as described above is made of a Co—Cr—Mo—Si—N alloy.

  This Co—Cr—Mo—Si—N-based alloy (hereinafter also referred to as “alloy”) includes Co as a main component, contains Cr in a proportion of 16% by mass to 35% by mass, and contains Mo. In a proportion of 3% by mass or more and 12% by mass or less, Si in a proportion of 0.3% by mass or more and 2.0% by mass or less, and N in a proportion of 0.09% by mass or more and 0.5% by mass or less. Is included.

  Such alloys have high corrosion resistance. For this reason, even if it touches seawater etc. over a long period of time or is exposed to ultraviolet rays, elution of constituent elements, deterioration of materials, and the like hardly occur. Therefore, even when the slide fastener 1 is used in, for example, seawater or the sea, corrosion of fastener parts is suppressed, and a highly reliable slide fastener 1 that can be smoothly opened and closed over a long period of time is obtained.

  Moreover, such an alloy has high deformation resistance. For this reason, for example, even when a foreign object is caught in the slide fastener 1, the deformation of the fastener parts is suppressed, and the smooth opening / closing operation is hardly hindered. As a result, a highly reliable slide fastener 1 is obtained.

  Furthermore, such alloys exhibit a high hardness. For this reason, it is possible to obtain a fastener component that has wear resistance and is hardly damaged. Since such a fastener component is excellent in wear resistance, for example, even when sliding is repeated over a long period of time, a decrease in operability associated with wear of the fastener component can be suppressed. As a result, a highly reliable slide fastener 1 that can be smoothly opened and closed over a long period of time is obtained.

  Such an alloy is made of a sintered metal powder, that is, manufactured by a powder metallurgy method. According to the powder metallurgy method, the shape of the fastener part can be easily approximated to the target shape, and thus a fastener part with high dimensional accuracy can be obtained. For this reason, the variation in the shape of the elements 12 is reduced, and the operation of engaging the engagement portions 122 or separating the engagement portions 122 engaged can be performed more smoothly. . As a result, the slide fastener 1 capable of a smoother opening / closing operation is obtained. Furthermore, the sintered body of the metal powder has a small crystal grain size of the metal structure and is highly isotropic. For this reason, the fastener component which has high deformation resistance with respect to the force from all directions is obtained.

  In addition, such an alloy should just comprise the site | part used for sliding at least among fastener components, and it does not specifically limit about the constituent material of the other site | part.

  Here, Co (cobalt) among the elements constituting this alloy is a main component of the alloy and greatly affects the basic characteristics of the alloy.

  The Co content is set so as to be the highest among the elements constituting this alloy. Specifically, it is preferably 50% by mass to 67.5% by mass, and more preferably 55% by mass to 67% by mass. It is more preferable that

Cr (chromium) mainly acts to improve the corrosion resistance of the alloy. This is presumably because an appropriate amount of passive film (Cr ₂ O ₃ or the like) is easily formed on the alloy by adding Cr, and chemical stability is improved. By improving the corrosion resistance, for example, an effect that metal ions are more difficult to elute even when contacted with seawater is expected. Therefore, the fastener part comprised with the alloy containing Cr becomes a thing excellent in corrosion resistance more. Moreover, the mechanical characteristic of a fastener component can be improved more because Cr is used with Co, Mo, and Si.

  The Cr content in the alloy constituting the fastener part is set to 16% by mass or more and 35% by mass or less. When the Cr content is less than the lower limit, the corrosion resistance of the fastener part is lowered. For this reason, when a fastener component contacts a body fluid for a long time, there exists a possibility that a large amount of metal ions may elute. On the other hand, when the Cr content exceeds the upper limit, the amount of Cr with respect to Mo or Si is excessively increased, and the balance of the contained elements is lost, so that the mechanical characteristics are deteriorated.

  The Cr content is preferably 26% by mass or more and 35% by mass or less, more preferably 27% by mass or more and 34% by mass or less, and further preferably 28% by mass or more and 33% by mass or less.

  Mo (molybdenum) mainly acts to increase the corrosion resistance of fastener parts. That is, the corrosion resistance due to the addition of Cr can be further enhanced by the addition of Mo. This is thought to be due to the fact that the passive film mainly composed of an oxide of Cr is further densified by adding Mo. Therefore, the alloy to which Mo is added further makes it difficult for metal ions to elute and contributes to the realization of a fastener part with particularly high corrosion resistance.

  The Mo content in the alloy is 3% by mass or more and 12% by mass or less. If the Mo content is below the lower limit, the corrosion resistance of the fastener part may be insufficient. On the other hand, when the Mo content exceeds the upper limit, the amount of Mo with respect to Cr and Si is excessively increased, and the balance of the contained elements is lost, so that the mechanical characteristics are deteriorated.

  The Mo content is preferably 5% by mass to 12% by mass, more preferably 5.5% by mass to 11% by mass, and even more preferably 6% by mass to 9% by mass. The

Si (silicon) mainly acts to increase the slipperiness of the surface of the fastener part. By adding Si, silicon oxide in which a part of Si is oxidized is generated in the fastener part. Examples of silicon oxide include SiO and SiO ₂ . When such silicon oxide is generated in the fastener part, the frictional resistance of the surface is reduced, and the sliding property when the fastener parts or between the fastener part and another member slides increases, and the slide fastener 1 is smooth. Opening and closing operation becomes possible.

On the other hand, Si (silicon) mainly acts to enhance the mechanical properties of the fastener part. By adding Si, silicon oxide in which a part of Si is oxidized is generated in the alloy. Examples of silicon oxide include SiO and SiO ₂ . Such silicon oxide suppresses the metal crystal from becoming significantly enlarged when the metal crystal grows during the manufacture of the fastener part. For this reason, in the alloy to which Si is added, the particle size of the metal crystal is kept small, and the mechanical characteristics of the fastener part can be further enhanced. In particular, when a Si atom substitutes a Co atom as a substitutional element, the crystal structure is slightly distorted and the Young's modulus is increased. Therefore, by adding Si, it is possible to achieve both excellent slipperiness of fastener parts and excellent mechanical properties, particularly excellent proof stress and Young's modulus. As a result, a fastener component that can be smoothly opened and closed and has higher deformation resistance is obtained.

  Moreover, in order to obtain the effects as described above, it is necessary to set the Si content to 0.3 mass% or more and 2.0 mass% or less. When the Si content is lower than the lower limit, the amount of silicon oxide is also reduced, resulting in a decrease in slipperiness and a tendency to enlarge metal crystals during the manufacture of fastener parts, resulting in a decrease in mechanical properties of the fastener parts. Is more likely to do. On the other hand, if the Si content exceeds the upper limit, the amount of silicon oxide present in the fastener part becomes too large, and a region in which silicon oxide is spatially continuously distributed tends to occur. In this region, there is a high possibility that the mechanical characteristics will deteriorate. Moreover, there exists a possibility that sliding property may fall with the silicon oxide distributed spatially continuously.

  The Si content is preferably 0.5% by mass or more and 1.0% by mass or less, and more preferably 0.6% by mass or more and 0.9% by mass or less.

  Further, as described above, it is preferable that a part of Si is present in the state of silicon oxide, but the abundance thereof is such that the ratio of Si contained as silicon oxide with respect to the total amount of Si is 20 mass. % To 80% by mass, more preferably 30% to 70% by mass, and even more preferably 35% to 65% by mass. By setting the ratio of Si contained as silicon oxide in the total Si within the above range, the fastener part has the effect of improving the mechanical properties as described above, while a certain amount of silicon oxide is present. By doing so, the amount of oxides of transition metal elements such as Co, Cr and Mo contained in the fastener part can be sufficiently suppressed. That is, since Si is easier to oxidize than Co, Cr and Mo, and Si causes a reduction reaction by depriving oxygen bonded to these transition metal elements, the total amount of Si is not silicon oxide. This is because it is considered to be equivalent to causing a sufficient reduction reaction to the transition metal element. Therefore, when the ratio of Si contained as silicon oxide in Si is within the above range, the fastener parts have the effects such as the above-described high mechanical characteristics and high slipperiness, and the oxidation of Co, Cr or Mo. It is suppressed that it is inhibited by a thing. As a result, a more reliable fastener part can be realized.

  On the other hand, it is considered that a certain amount of silicon oxide contributes to forming a chemically stable film together with chromium oxide and molybdenum oxide by supplying oxygen from the outside air on the surface of the fastener part. For this reason, chemical stability is imparted to the surface of the fastener part, which leads to higher corrosion resistance of the fastener part.

  Moreover, moderate hardness and slipperiness will be given with respect to fastener components by setting the ratio of Si contained as silicon oxide of Si in the said range. That is, when a certain amount of Si that is not silicon oxide exists, at least one of Co, Cr, and Mo and Si produce a hard intermetallic compound, which increases the hardness and slipperiness of the fastener part. Conceivable. By increasing the hardness of the fastener component, the wear resistance can be increased.

  In addition, since the remarkable growth of metal crystals is inhibited by adding Si, the hardness of fastener parts tends to decrease from that viewpoint, but a part of Si generates intermetallic compounds. It is considered that this hardness is suppressed from significantly lowering, and an appropriate hardness as described later and sufficient toughness resulting from the appropriate hardness can be obtained.

The intermetallic compound is not particularly limited, and an _{example, CoSi 2, Cr 3 Si,} MoSi 2, Mo 5 Si 3 and the like.

  In consideration of the amount of precipitation of the intermetallic compound, the ratio of Si content to the Mo content (Si / Mo) is preferably 0.05 or more and 0.2 or less in terms of mass ratio. More preferably, it is 0.15 or less. Thereby, high slipperiness and high mechanical properties can be imparted to the fastener part.

  The silicon oxide may be distributed at any position, but is preferably distributed so as to segregate at the grain boundary (interface between metal crystals). When the silicon oxide is segregated at such a position, the enlargement of the metal crystal is more reliably suppressed, and a fastener part having more excellent mechanical characteristics can be obtained. Moreover, since the silicon oxide precipitates segregated at the grain boundaries naturally maintain an appropriate distance, the silicon oxide precipitates can be more uniformly dispersed in the fastener part. As a result, the probability that the silicon oxide is spatially continuously distributed is lowered, so that the deterioration of the mechanical properties based on the silicon oxide can be avoided and the slipperiness of the fastener part can be further improved.

  Moreover, about the segregated silicon oxide deposit, its size, distribution, etc. can be specified by surface analysis of qualitative analysis. Specifically, in the composition image of Si by an electron beam microanalyzer (EPMA), the average diameter of the region where Si is segregated is preferably 0.1 μm or more and 10 μm or less, and is 0.3 μm or more and 8 μm or less. Is more preferable. If the average diameter of the region where Si is segregated is within the above range, the size of the silicon oxide precipitates is optimal for achieving the effects as described above. That is, when the average diameter of the region where Si is segregated is less than the lower limit value, the silicon oxide precipitates are not segregated to a sufficient size, and the above effects may not be sufficiently obtained. On the other hand, if the average diameter of the region where Si is segregated exceeds the upper limit, the mechanical properties of the fastener part may be deteriorated.

  The average diameter of the region where Si is segregated is obtained as the average value of the diameters of circles having the same area as that of the region where Si is segregated (projected area circle equivalent diameter) in the Si composition image. Can do.

The fastener part includes a first phase mainly composed of Co and a second phase mainly composed of Co ₃ Mo. Among these, since the second phase is included, the fastener component is provided with high hardness and high slipperiness as in the case of the intermetallic compound containing Si described above, so that the fastener component useful from the viewpoint of improving reliability. Is obtained. On the other hand, when the second phase is excessively contained, it is remarkably easily segregated, and there is a possibility that the mechanical properties are deteriorated.

Therefore, it is preferable that the first phase and the second phase are included in an appropriate ratio from the above viewpoint. Specifically, the fastener part is subjected to a crystal structure analysis by an X-ray diffraction method using CuKα rays, and when the highest peak height among the peaks due to Co is set to 1, it is attributed to Co ₃ Mo. Of the peaks, the height of the highest peak is preferably 0.01 or more and 0.5 or less, and more preferably 0.02 or more and 0.4 or less.

Further, when the ratio of the peak height of Co ₃ Mo when the height of the peak of Co is 1 is below the lower limit value, depending on the composition of the alloy, the ratio of Co ₃ Mo to Co in the fastener part Since the ratio decreases, the hardness and slipperiness may decrease. On the other hand, when the ratio of the height of the peak of Co 3 _Mo exceeds the above upper limit, the composition of the alloy will become excessive abundance of Co 3 _Mo, fastener parts Co 3 _Mo becomes liable to significantly segregated There is a possibility that the mechanical properties of the material may deteriorate and the slipperiness may also decrease.
CuKα rays are usually characteristic X-rays with energy of 8.048 keV.

Further, when identifying a peak due to Co, it is identified based on a Co database of an ICDD (The International Center for Diffraction Data) card. Similarly, when identifying a peak due to Co ₃ Mo, the peak is identified based on the Co ₃ Mo database of the ICDD card.

In the fastener part, the proportion of Co ₃ Mo is preferably 0.01% by mass or more and 10% by mass or less, and more preferably 0.05% by mass or more and 5% by mass or less. Thereby, the fastener component which made high hardness and high slipperiness compatible is obtained.

These abundance ratios are obtained by quantifying the abundance ratio of Co ₃ Mo from the results of crystal structure analysis.

  Moreover, the alloy which comprises at least one part of fastener components contains N (nitrogen) in addition to each element as mentioned above. N mainly acts to enhance the mechanical properties of the fastener part. Since N is an austenitizing element, it acts to promote the austenitizing of the crystal structure of the fastener part and increase the toughness.

  In addition, by including N, the fastener part composed of the sintered body of the metal powder can suppress the generation of the dendrite phase and has a very small dendrite phase content. From such a viewpoint, toughness can be increased.

  Therefore, the fastener component containing N has moderate hardness, high toughness, and low dendrite phase content. For this reason, such fastener parts have high slipperiness.

  Here, the dendrite phase is a crystal structure grown in a dendritic shape, but if such a dendrite phase is contained in a large amount, mechanical properties and slipperiness of the fastener part are lowered. Therefore, reducing the dendrite phase content is effective in increasing the mechanical properties and slipperiness of the fastener part. Specifically, the fastener part is observed with a scanning electron microscope, and the area ratio occupied by the dendrite phase in the obtained observation image is preferably 20% or less, and more preferably 10% or less. Fastener parts satisfying such conditions are particularly excellent in mechanical properties and slipperiness.

  Moreover, the fastener component is comprised by the sintered compact of the metal powder as mentioned above. Since the volume of each particle is very small, the metal powder has a high cooling rate and high cooling uniformity. For this reason, in the fastener part comprised with the sintered compact of such a metal powder, the production | generation of a dendrite phase is suppressed. On the other hand, in the conventional methods such as casting, forging, and rolling, when cooling the molten metal, the volume to be cooled is larger than in the conventional method, so the cooling rate is reduced and the cooling uniformity is also lowered. As a result, it is considered that a relatively large amount of dendrite phase is generated in the fastener part manufactured by such a method.

  The area ratio described above is calculated as the ratio of the area occupied by the dendrite phase to the area of the observation image, and one side of the observation image is set to about 50 μm or more and 1000 μm or less.

In order to obtain the effects as described above, the N content needs to be set to 0.09 mass% or more and 0.5 mass% or less. If the N content is less than the lower limit, depending on the alloy composition, the crystal structure of the fastener part is not sufficiently austenitized, and therefore the hardness of the fastener part is excessively high and the toughness is also liable to decrease. There is a risk. This is considered to be because a lot of hcp structure (ε phase) precipitates in addition to the austenite phase (γ phase) in the fastener part. As a result, the mechanical properties and slipperiness of the fastener part may be reduced. On the other hand, if the N content exceeds the upper limit, depending on the composition of the alloy, a large amount of various nitrides may be generated and the composition may be difficult to sinter. For this reason, there is a possibility that the sintered density of the fastener part is lowered and the mechanical properties are lowered. Examples of the generated nitride include Cr ₂ N. When such a nitride precipitates, the hardness also increases, so the toughness also decreases.

  The content of N is preferably 0.12% by mass or more and 0.4% by mass or less, more preferably 0.14% by mass or more and 0.25% by mass or less, and further preferably 0.15% by mass. % Or more and 0.22% by mass or less.

  In particular, in the range of 0.15% by mass or more and 0.22% by mass, the austenite phase becomes particularly dominant, and a remarkable improvement in toughness is observed as the hardness decreases. When the fastener component at this time is subjected to crystal structure analysis by X-ray diffraction using CrKα rays, the main peak due to the austenite phase is very strongly recognized, while the peak due to the hcp structure and other peaks are All are 5% or less of the height of the main peak. This shows that the austenite phase is dominant.

  On the other hand, the ratio of the content ratio of N to the content ratio of Si (N / Si) is preferably 0.1 or more and 0.8 or less, and more preferably 0.2 or more and 0.6 or less in terms of mass ratio. preferable. Thereby, it is possible to achieve both high mechanical properties in the fastener part and high corrosion resistance on the surface of the fastener part. That is, when a certain amount of Si is added, as described above, the slipperiness becomes higher and the corrosion resistance on the surface becomes higher. On the other hand, if the amount of Si added is too large, the amount of silicon oxide generated becomes too large. For this reason, the mechanical properties of the fastener part may be deteriorated. Therefore, when N is added at a ratio within the above range, the high slipperiness and high corrosion resistance due to the addition of Si and the above-described effects due to the addition of N can be exhibited without canceling each other. As a result, synergistic improvement in slipperiness can be achieved. This is thought to be because Si and a metal element such as Co produce a substitutional solid solution, whereas a metal element such as N and Co produces an interstitial solid solution and can coexist with each other. In addition, it is considered that the distortion of the crystal structure due to the solid solution of Si is also suppressed due to the solid solution of N, which is considered to prevent the deterioration of mechanical properties.

  When Si is added, the crystal structure is distorted as described above. However, in this state, hysteresis tends to occur in the behavior of thermal expansion and contraction. If there is a large hysteresis in the behavior of thermal expansion and contraction, the thermal characteristics of the fastener part may change over time.

  On the other hand, when N is added at the above-described ratio, N penetrates into the crystal structure and dissolves therein, so that distortion of the crystal structure is suppressed. As a result, hysteresis in the behavior of thermal expansion and contraction is suppressed, and the thermal characteristics of the fastener part can be stabilized.

  From the above, by appropriately adding Si and N, it is possible to improve the slipperiness of the fastener part and to stabilize the mechanical characteristics and the thermal characteristics of the fastener part.

  In addition, when the ratio of the content rate of N with respect to the content rate of Si is less than the said lower limit, depending on the composition of the alloy, the distortion of the crystal structure cannot be sufficiently suppressed, and the toughness and the like may be reduced. On the other hand, if it exceeds the upper limit, depending on the composition of the alloy, the composition becomes difficult to sinter, the sintered density of the fastener part is lowered, and the mechanical properties may be lowered.

  Moreover, the alloy which comprises at least one part of fastener components may contain C (carbon) other than each element as mentioned above. The addition of C increases the hardness and tensile strength of the fastener part, and also improves the slipperiness. Although the detailed reason why the slipperiness becomes high is not clear, it is considered that one of the reasons is that the frictional resistance is reduced by the formation of carbide.

  The content of C in the alloy constituting the fastener part is not particularly limited, but is preferably 1.5% by mass or less, and more preferably 0.7% by mass or less. If the C content exceeds the upper limit, depending on the composition of the alloy, the brittleness of the fastener part increases, and the mechanical properties may deteriorate.

  Further, the lower limit value of the addition amount is not particularly set, but the lower limit value is preferably set to about 0.05% by mass in order to sufficiently exhibit the above-described effects.

  The C content is preferably about 0.02 to 0.5 times the Si content, more preferably about 0.05 to 0.3 times. By setting the ratio of C to Si within the above range, it is considered that silicon oxide and carbides act synergistically in improving slipperiness while minimizing the adverse effects of fastener parts on hardness and mechanical properties. . For this reason, it is possible to obtain a fastener component that is particularly excellent in slipperiness.

  Further, the N content is preferably about 0.3 to 10 times the C content, more preferably about 2 to 8 times. By setting the ratio of N to C within the above range, it is possible to particularly achieve both improvement in slipperiness of the fastener part by addition of C and improvement in mechanical characteristics of the fastener part by addition of N.

  Further, at least one of Ni, Fe, and Mn may be added to the alloy constituting at least a part of the fastener part, if necessary.

  Among these, Ni acts mainly to add characteristics suitable for forging to the sintered body. That is, the plastic workability of the sintered body can be increased by adding Ni (for example, ductility and malleability can be increased, or hardness can be optimized).

  The Ni content in this alloy is preferably set to 0.3 mass% or more and 15 mass% or less, more preferably set to 0.5 mass% or more and 13 mass% or less, and more preferably 1 mass% or more. More preferably, it is set to 12% by mass or less. By setting the Ni content within the above range, sufficient plastic workability can be imparted to the sintered body without significantly impairing the excellent characteristics of the alloy as described above. Thereby, after manufacturing a sintered compact, it can deform | transform into a target shape further by methods, such as hot forging and cold forging. Forging includes die forging and free forging, and any of them may be used.

  Among the fastener parts, the element 12 is manufactured by forging the sintered body, so that, for example, the shape of the engaging portion 122 with high dimensional accuracy can be easily formed, and therefore a smooth opening and closing operation can be realized. Become.

  Further, Fe and Mn respectively impart elongation and flexibility (toughness) to the sintered body. Thereby, plastic workability can be improved and the occurrence of cracks, chips and the like can be suppressed.

  The Fe content in this alloy is preferably 6% by mass or less, more preferably 5.5% by mass or less, and even more preferably 5% by mass or less. If the Fe content exceeds the upper limit, the corrosion resistance of the fastener part may be lowered depending on the composition of the alloy.

  In addition, although a lower limit is not specifically limited, It is set as about 0.3 mass%. Below this, there is a possibility that sufficient effects cannot be obtained.

  The Mn content in this alloy is preferably 3% by mass or less, more preferably 2.5% by mass or less, and further preferably 2% by mass or less. If the Mn content exceeds the above upper limit, depending on the composition of the alloy, the elongation and flexibility of the sintered body may be impaired.

  In addition, although a lower limit is not specifically limited, It is set as about 0.3 mass%. Below this, there is a possibility that sufficient effects cannot be obtained.

  In addition, the alloy constituting at least a part of the fastener component is allowed to contain impurities inevitably generated during production, in addition to the elements described above. In that case, the total content of impurities is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.2% by mass or less. Examples of such an impurity element include B, O, Na, Mg, Al, P, and S.

  On the other hand, when the slide fastener 1 is used in an application such as a scuba diving suit that frequently touches the human body, the alloy constituting at least a part of the fastener component is substantially Ni. It is preferable not to contain (nickel). Ni is also an element that is concerned about the influence on the living body as an element having a particularly high sensitization rate among the causative substances (allergens) of metal allergy. The fact that the fastener part does not substantially contain Ni is effective from the viewpoint of suppressing the occurrence of metal allergy. Therefore, a fastener part that does not substantially contain Ni is less likely to cause metal allergy and is particularly highly compatible with a living body. In consideration of the case of inevitably mixing, the Ni content is preferably 0.05% by mass or less, more preferably 0.03% by mass or less.

  Of the alloy constituting at least a part of the fastener part, the balance of each element as described above is Co. As described above, the Co content is set to be the highest among the elements contained in the alloy.

  The constituent elements and composition ratios in the alloy are, for example, the atomic absorption method specified in JIS G 1257, the ICP emission analysis method specified in JIS G 1258, the spark emission analysis method specified in JIS G 1253, and the JIS. It can be specified by a fluorescent X-ray analysis method defined in G 1256, a weight, titration, absorptiometry or the like defined in JIS G 1211-G 1237. Specifically, a solid-state emission spectroscopic analyzer (spark emission analyzer) manufactured by SPECTRO, model: SPECTROLAB, type: LAVMB08A may be mentioned.

  Further, when specifying C (carbon) and S (sulfur), in particular, an oxygen stream combustion (high frequency induction furnace combustion) -infrared absorption method defined in JIS G1211 is also used. Specifically, a carbon / sulfur analyzer manufactured by LECO, CS-200 may be mentioned.

  Furthermore, in specifying N (nitrogen) and O (oxygen), in particular, the nitrogen determination method for iron and steel specified in JIS G 1228 and the oxygen determination method for metal materials specified in JIS Z 2613 are also used. Specific examples include an oxygen / nitrogen analyzer manufactured by LECO, TC-300 / EF-300.

  Further, as described above, the fastener component shown in FIG. 1 is made of a sintered metal powder, that is, manufactured by a powder metallurgy method. Such fastener parts are excellent in corrosion resistance and mechanical properties (for example, toughness, proof stress, etc.) compared to those manufactured by, for example, a casting method. This is because fastener parts manufactured by powder metallurgy are manufactured using metal powder obtained by rapid cooling (because of its small volume, it is easy to be rapidly cooled), so metal compared to casting methods, etc. It is considered that remarkable grain growth of crystals is difficult to occur, and therefore, enlarged metal crystals are difficult to be generated. In addition, according to the powder metallurgy method, the composition tends to be uniform, and therefore the distribution of Si and silicon oxide tends to be uniform. Therefore, a fastener component having uniform slipperiness and corrosion resistance can be obtained, and differences between individuals can be kept small.

  The alloy containing N is composed of a sintered body obtained by dissolving N in the material from the time of producing the metal powder and using the powder. For this reason, N is distributed almost uniformly in the fastener part, and the physical properties can be made almost uniform. Therefore, such fastener parts have high homogeneity and individual differences are further suppressed.

  As described above, the homogeneity of fastener parts is derived from the fact that N is solid-dissolved in a metal material from the time of powder production and is composed of a sintered body produced by powder metallurgy using the powder. It is thought that. In order to solidify N in the metal material at the time of powder production, for example, a method in which at least one of Co, Cr, Mo and Si contained in the raw material is previously nitrided, when the raw material is melted or melted A method of holding the molten metal (molten metal) in a nitrogen gas atmosphere, a method of injecting nitrogen gas into the molten metal (bubbling with nitrogen gas), or the like is used later.

  Note that a molded body formed by molding a metal powder or a sintered body formed by sintering the metal powder is heated in a nitrogen gas atmosphere or subjected to HIP treatment in a nitrogen gas atmosphere to alloy N. There is also a method of impregnating inside (nitriding treatment). However, in these methods, it is difficult to uniformly nitride from the surface layer portion to the inner layer portion of the molded body or the sintered body, and even if it can be done, it is necessary to perform it for a very long time while suppressing the nitriding rate. There is a slight problem in terms of manufacturing efficiency of fastener parts.

  Further, in the case of degreasing and firing a molded body obtained by dissolving N in powder, degreasing and firing in an inert gas such as nitrogen gas or argon gas, the solid solution of N Variation in density can be suppressed.

  As the metal powder (metal powder for powder metallurgy of the present invention) used for manufacturing fastener parts, a powder composed of an alloy as described above is used. The average particle diameter is preferably 3 μm or more and 100 μm or less, more preferably 4 μm or more and 80 μm or less, and further preferably 5 μm or more and 60 μm or less. By using a metal powder having such a particle size, a fastener part having high density, high corrosion resistance and mechanical properties, and excellent slipperiness can be produced.

  The average particle size is determined as the particle size when the cumulative amount from the small diameter side is 50% on the mass basis in the particle size distribution obtained by the laser diffraction method.

  Further, when the average particle size of the metal powder is below the lower limit, the formability in powder metallurgy is lowered, so that the density of the fastener part is lowered, and the corrosion resistance and mechanical properties may be lowered. On the other hand, when the average particle diameter of the metal powder exceeds the upper limit, the metal powder filling property is reduced in powder metallurgy, so that the density of the fastener part may also be lowered and the mechanical characteristics may be lowered. In addition, the uniformity of the composition may be impaired.

  The particle size distribution of the metal powder is preferably as narrow as possible. Specifically, when the average particle size of the metal powder is within the above range, the maximum particle size is preferably 200 μm or less, and more preferably 150 μm or less. By controlling the maximum particle size of the metal powder within the above range, the particle size distribution of the metal powder can be narrowed, and the corrosion resistance, mechanical properties and surface slipperiness of the fastener parts can be further improved. .

  In addition, said maximum particle size means a particle size when the accumulation amount from a small diameter side becomes 99.9% on the mass basis in the particle size distribution obtained by the laser diffraction method.

  Further, when the short diameter of the metal powder particles is PS [μm] and the long diameter is PL [μm], the average aspect ratio defined by PS / PL is about 0.4 or more and 1 or less. Is preferable, and it is more preferably about 0.7 or more and 1 or less. The metal powder having such an aspect ratio has a shape that is relatively close to a sphere, so that the filling rate when compacted is increased. As a result, it is possible to obtain a fastener component having high corrosion resistance, mechanical properties and surface slipperiness.

  The major axis is the maximum length that can be taken in the projected image of the particle, and the minor axis is the maximum length in a direction orthogonal to the maximum length. Moreover, the average value of aspect ratio is calculated | required as an average value of the measured value about 100 particles or more of metal powder.

  On the other hand, in the cross section of the fastener part, when the major axis of one crystal structure is CL and the minor axis is CS, the average value of the aspect ratio of the crystal structure defined by CS / CL is about 0.4 or more and about 1 or less. It is preferable that it is about 0.5 or more and 1 or less. Since the crystal structure having such an aspect ratio has a small anisotropy, it contributes to the realization of a fastener part exhibiting mechanical properties such as excellent yield strength regardless of the direction of the applied force.

  The major axis is the maximum length that one crystal structure can take in the observed image of the cross-section of the fastener component, and the minor axis is the maximum length in the direction orthogonal to the maximum length. Moreover, the average value of aspect ratio is calculated | required as an average value of the measured value about 100 or more crystal structures.

  Moreover, it is preferable that the fastener component has a minute independent void | hole in the inside. By having such a hole, even if a crack or the like occurs inside the fastener part, the progress of the crack is likely to stop when the crack reaches the hole. For this reason, further progress of cracks can be prevented, and the fastener component can be prevented from being broken. Therefore, such fastener parts are more excellent in mechanical properties such as tensile strength. Furthermore, when this hole is exposed on the surface, when the fastener part comes into contact with another member, the contact area of the surface is suppressed, so that the frictional resistance can be reduced, and the slipping property of the fastener part can be further improved. it can.

  The average diameter of the pores is preferably 0.1 μm or more and 10 μm or less, and more preferably 0.3 μm or more and 8 μm or less. If the average diameter of the vacancies is within the above range, the vacancies themselves are less likely to be the starting point of cracks, and the vacancies have a certain volume, so that the probability of stopping the progress of cracks can be increased, The slipperiness can be increased. That is, by optimizing the hole diameter, the mechanical properties of the entire fastener part can be further improved by reducing the probability of crack growth while suppressing an increase in the probability of crack occurrence, and the fastener part. The slipperiness of can be improved.

  The average diameter of the holes can be obtained as an average value of the diameters of circles having the same area as the holes (projected area circle equivalent diameter) in the scanning electron microscope image of the cross section of the fastener part.

  In the observation image of the fastener part, the area ratio occupied by the holes is preferably 0.001% or more and 1% or less, and more preferably 0.005% or more and 0.5% or less. If the area ratio which a hole occupies is in the said range, the mechanical characteristics and slipperiness of a fastener component can be improved more.

  This area ratio is calculated as the ratio of the area occupied by the holes to the area of the observation image, and one side of the observation image is set to about 50 μm or more and 1000 μm or less.

  The fastener parts preferably have a Vickers hardness of 200 or more and 480 or less, and more preferably 240 or more and 380 or less. A fastener component having such hardness has excellent wear resistance and can be smoothly opened and closed over a long period of time.

  In addition, the Vickers hardness of a fastener component is measured based on the test method prescribed | regulated to JISZ2244.

  Further, the tensile strength of the fastener part is preferably 520 MPa or more, and more preferably 600 MPa or more and 1500 MPa or less. A fastener component having such a tensile strength is excellent in deformation resistance over a long period of time even when subjected to repeated opening and closing operations.

  Similarly, the 0.2% yield strength of the fastener part is preferably 450 MPa or more, and more preferably 500 MPa or more and 1200 MPa or less. Such a 0.2% yield strength fastener part is excellent in deformation resistance over a long period of time even when subjected to repeated opening and closing operations.

  These tensile strength and 0.2% proof stress are measured according to the test method defined in JIS Z 2241.

  Furthermore, the elongation of the fastener part is preferably 2% or more and 50% or less, and more preferably 10% or more and 45% or less. A fastener part having such an elongation is excellent in impact resistance because it is less likely to be broken or cracked.

  The elongation (breaking elongation) of the fastener part is measured in accordance with a test method defined in JIS Z 2241.

  The Young's modulus of the fastener part is preferably 150 GPa or more, and more preferably 170 GPa or more and 300 GPa or less. Fastener parts having such Young's modulus are particularly difficult to deform.

  Further, when the corrosion resistance to salt water is evaluated according to the salt spray test method specified in JIS Z 2371 for fastener parts, the surface corrosion area ratio after 24 hours is preferably 1% or less, 0.5 % Or less is more preferable. Such a fastener part can be used for a long time even in seawater. In addition, the sodium chloride density | concentration of the salt water to be used is 5 g / L, and test temperature shall be 25 degreeC.

  Examples of the metal powder used in the manufacture of fastener parts include various powdering methods such as an atomizing method (for example, a water atomizing method, a gas atomizing method, a high-speed rotating water atomizing method, etc.), a reduction method, a carbonyl method, and a pulverizing method. Can be produced.

  Of these, those manufactured by the atomizing method are preferably used, and those manufactured by the water atomizing method or the high-speed rotating water atomizing method are more preferably used. The atomizing method is a method for producing a metal powder by causing molten metal (molten metal) to collide with a fluid (liquid or gas) jetted at high speed, thereby pulverizing and cooling the molten metal. By producing metal powder by such an atomizing method, extremely fine powder can be efficiently produced. Moreover, the particle shape of the obtained powder becomes close to a spherical shape due to the effect of surface tension. For this reason, a molded object with a high filling rate is obtained when metal powder is shape | molded in the powder metallurgy method. As a result, a fastener part having excellent mechanical properties can be obtained.

[Fastener parts manufacturing method]
Next, an embodiment of a method for manufacturing a fastener part according to the present invention will be described.

  The method of manufacturing a fastener component according to the present embodiment includes a step of forming the metal powder for powder metallurgy (the metal powder for powder metallurgy of the present invention) and obtaining a formed body, and firing the formed body to obtain a sintered body. And obtaining a step. Hereinafter, each step will be described in detail.

[1]
[1-1] Kneading Step First, a metal powder for powder metallurgy is kneaded together with an organic binder to obtain a kneaded product.

  The content of the organic binder in the kneaded product is appropriately set according to molding conditions, the shape to be molded, etc., but is preferably about 2% by mass or more and 20% by mass or less of the entire kneaded product, and is preferably 5% by mass or more. More preferably, it is about 10% by mass or less. By setting the content of the organic binder within the above range, the kneaded product has good fluidity. Thereby, the filling property of the kneaded material at the time of molding is improved, and a sintered body having a shape (near net shape) closer to the target shape is finally obtained.

  Examples of the organic binder include polyolefins such as polyethylene, polypropylene, and ethylene-vinyl acetate copolymer, acrylic resins such as polymethyl methacrylate and polybutyl methacrylate, styrene resins such as polystyrene, polyvinyl chloride, and polyvinylidene chloride. Polyesters such as polyamide, polyethylene terephthalate, polybutylene terephthalate, polyethers, polyvinyl alcohol, polyvinyl pyrrolidone or copolymers thereof, various waxes, paraffin, higher fatty acids (eg stearic acid), higher alcohols, higher alcohols Examples include various organic binders such as fatty acid esters and higher fatty acid amides, and one or more of these can be used in combination.

  Moreover, a plasticizer may be added to the kneaded material as necessary. Examples of the plasticizer include phthalic acid esters (eg, DOP, DEP, DBP), adipic acid esters, trimellitic acid esters, sebacic acid esters, and the like, and one or more of these are mixed. Can be used.

  In addition to the metal powder for powder metallurgy, the organic binder, and the plasticizer, various additives such as a lubricant, an antioxidant, a degreasing accelerator, and a surfactant are added to the kneaded material as necessary. be able to.

  The kneading conditions vary depending on various conditions such as the metal composition and particle size of the metal powder for powder metallurgy used, the composition of the organic binder, and the blending amount thereof. For example, the kneading temperature is 50 ° C. or higher and 200 ° C. The kneading time can be about 15 minutes to 210 minutes.

  Further, the kneaded product is formed into pellets (small lumps) as necessary. The particle size of the pellet is, for example, about 1 mm to 15 mm.

  In addition, you may make it manufacture granulated powder instead of a kneaded material. These kneaded materials, granulated powders, and the like are examples of compositions that are subjected to the molding step described later.

[1-2] Molding Step Next, the kneaded product is molded to produce a molded body having the same shape as the fastener part.

  The molding method is not particularly limited, and various molding methods such as a compacting (compression molding) method, a metal powder injection molding (MIM) method, and an extrusion molding method can be used. Among these, the metal powder injection molding method is preferably used from the viewpoint that a sintered body having a near net shape can be manufactured.

In addition, the molding conditions in the compacting method vary depending on various conditions such as the composition and particle size of the metal powder for powder metallurgy used, the composition of the organic binder, and the blending amount thereof, but the molding pressure is 200 MPa or more and 1000 MPa or less. It is preferably about (2 t / cm ² or more and 10 t / cm ² or less).

In addition, although the molding conditions in the metal powder injection molding method are different depending on various conditions, the material temperature is about 80 ° C. to 210 ° C., and the injection pressure is 50 MPa to 500 MPa (0.5 t / cm ^{2 to} 5 t / cm ² or less) is preferable.

In addition, although the molding conditions in the extrusion molding method are different depending on various conditions, the material temperature is about 80 ° C. or more and 210 ° C. or less, and the extrusion pressure is 50 MPa or more and 500 MPa or less (0.5 t / cm ² or more and 5 t / cm ² or less. ) Is preferable.

  The molded body thus obtained is in a state where the organic binder is uniformly distributed in the gaps between the particles of the metal powder.

  In addition, the shape dimension of the molded object produced is determined in consideration of the shrinkage | contraction part of the molded object in a subsequent degreasing process and a baking process.

  Moreover, you may make it perform machining, such as cutting, grinding | polishing, and cutting | disconnection, with respect to a molded object as needed. Since the molded body has a relatively low hardness and is relatively rich in plasticity, it can be easily machined while preventing the shape of the molded body from collapsing. According to such machining, a fastener part with high dimensional accuracy can be obtained more easily.

[2]
[2-1] Degreasing step Next, the obtained molded body is subjected to degreasing treatment (debinding treatment) to obtain a degreased body.

  Specifically, the molded body is heated to decompose the organic binder, whereby at least a part of the organic binder is removed from the molded body, and degreasing treatment is performed.

  Examples of the degreasing treatment include a method of heating the molded body, a method of exposing the molded body to a gas that decomposes the binder, and the like.

  When using the method of heating the molded body, the heating condition of the molded body is slightly different depending on the composition and blending amount of the organic binder, but the temperature is about 100 ° C. or higher and 750 ° C. or lower × 0.1 hour or longer and 20 hours or shorter. Preferably, it is about 150 to 600 ° C. × 0.5 to 15 hours. Thereby, degreasing | defatting of a molded object can be performed sufficiently and necessary, without sintering a molded object. As a result, it is possible to reliably prevent a large amount of the organic binder component from remaining in the degreased body.

The atmosphere for heating the molded body is not particularly limited, and is a reducing gas atmosphere such as hydrogen, an inert gas atmosphere such as nitrogen or argon, an oxidizing gas atmosphere such as air, or these atmospheres. The reduced pressure atmosphere etc. which reduced pressure is mentioned.
On the other hand, examples of the gas that decomposes the binder include ozone gas.

  In addition, such a degreasing process is decomposed | disassembled and removed so that it may not remain | survive in a molded object more rapidly by performing in multiple processes (step) from which degreasing conditions differ. be able to.

  Moreover, you may make it perform machining, such as cutting, grinding | polishing, and cutting | disconnection with respect to a degreased body as needed. Since the degreased body is relatively low in hardness and relatively rich in plasticity, it can be easily machined while preventing the shape of the degreased body from collapsing. According to such machining, a fastener part with high dimensional accuracy can be obtained more easily.

[2-2] Firing step Next, the obtained degreased body is fired in a firing furnace to obtain a sintered body. That is, diffusion occurs at the interface between the particles of the metal powder for powder metallurgy, resulting in sintering. As a result, a sintered body is obtained.

  The firing temperature varies depending on the composition, particle size and the like of the metal powder for powder metallurgy, but as an example, it is about 900 ° C. or higher and 1400 ° C. or lower. The temperature is preferably about 1050 ° C. or higher and 1300 ° C. or lower.

  The firing time is 0.2 hours or more and 7 hours or less, and preferably 1 hour or more and 6 hours or less.

  In the firing step, the sintering temperature or a firing atmosphere described later may be changed during the firing process.

  Further, the atmosphere during firing is not particularly limited, but in consideration of preventing significant oxidation of the metal powder, a reducing gas atmosphere such as hydrogen, an inert gas atmosphere such as argon, or these atmospheres The reduced pressure atmosphere etc. which reduced pressure is preferably used.

  Moreover, you may make it perform a HIP process (hot isostatic pressing process) etc. with respect to the sintered compact obtained in this way. Thereby, the density of the sintered body can be further increased, and a fastener part having more excellent mechanical characteristics can be obtained.

  As conditions for the HIP treatment, for example, the temperature is 850 ° C. or more and 1200 ° C. or less, and the time is about 1 hour or more and 10 hours or less.

  Further, the applied pressure is preferably 50 MPa or more, and more preferably 100 MPa or more.

  In this way, a sintered body is obtained, and a fastener part having at least a part of the sintered body is obtained.

  In addition, you may make it perform a grinding | polishing process to the obtained sintered compact as needed. Examples of the polishing treatment include barrel polishing and sand blasting.

  On the other hand, the sintered body thus obtained is useful as a metal material having excellent corrosion resistance and slipperiness. Therefore, for the sintered body obtained by the method as described above, for example, machining such as cutting, grinding, laser processing, electron beam processing, water jet processing, electric discharge processing, press processing, extrusion processing, rolling processing, Various fastener parts may be manufactured by forming into a target shape by performing forging, bending, drawing, drawing, rolling, shearing, or the like. In addition, when giving such a process, the shape of the sintered compact used for the process does not necessarily need to be a shape close | similar to the target shape finally, and it is preferable to make it the shape which is easy to process.

  And this metal material can be used not only for fastener parts but also for any article as long as it is used for applications that require corrosion resistance and slipperiness. Examples of such articles include various automobile parts, various railway vehicle parts, various aircraft parts, various machine parts, and the like.

  Moreover, the metal powder for powder metallurgy of the present invention described above is used for manufacturing various fastener parts by appropriately selecting the shape of the molded body. By using such metal powder for powder metallurgy, it is possible to easily manufacture a fastener component having a target shape with almost no post-processing. Then, the obtained fastener part has both corrosion resistance and slipperiness as described above.

As mentioned above, although the manufacturing method of the fastener component of this invention, the metal powder for powder metallurgy, and a fastener component was demonstrated based on suitable embodiment, this invention is not limited to this.
For example, an arbitrary process may be added to the method for manufacturing a fastener part of the present invention.

Next, specific examples of the present invention will be described.
1. Test piece production (Sample No. 1)
[1] First, raw materials having the alloy compositions shown in Table 1 were melted in a high frequency induction furnace and pulverized by a water atomization method to obtain a metal powder. Subsequently, classification was performed using a standard sieve having an opening of 150 μm. N was included in the raw material in a state of being bonded to Cr (in the state of chromium nitride). Moreover, SPECTRO Co., Ltd. solid emission spectroscopic analyzer (spark emission analyzer), model: SPECTROLAB, type: LAVMB08A was used for specifying the alloy composition. For quantitative analysis of C (carbon), a carbon / sulfur analyzer, CS-200, manufactured by LECO, was used. Further, an oxygen / nitrogen analyzer manufactured by LECO, TC-300 / EF-300, was used for quantitative analysis of N (nitrogen).

[2] Next, the metal powder and a mixture of polypropylene and wax (organic binder) were weighed and mixed so as to have a mass ratio of 9: 1 to obtain a mixed raw material.
[3] Next, this mixed raw material was kneaded with a kneader to obtain a kneaded product.

  [4] Next, the kneaded product was molded with an injection molding machine under the molding conditions shown below to produce a molded body.

<Molding conditions>
-Material temperature: 150 ° C
Injection pressure: 11 MPa (110 kgf / cm ² )

[5] Next, this molded body was degreased under the following degreasing conditions to obtain a degreased body.
<Degreasing conditions>
・ Heating temperature: 470 ° C
・ Heating time: 1 hour ・ Heating atmosphere: Nitrogen atmosphere

  [6] Next, the obtained degreased body was fired under the following firing conditions to obtain a sintered body. As a result, a test piece was obtained.

<Baking conditions>
・ Heating temperature: 1300 ℃
・ Heating time: 3 hours ・ Heating atmosphere: Argon atmosphere

(Sample Nos. 2-17)
Except for the production conditions shown in Table 1, sample No. A test piece was obtained in the same manner as in 1.

(Sample No. 18-21)
When melting the raw material in a high frequency induction furnace, nitrogen gas was injected into the molten metal. At this time, the N content was changed by appropriately changing the injection time.

  Samples other than those shown in Table 1 except for the other production conditions are shown in Table 1. A test piece was obtained in the same manner as in 1.

(Sample Nos. 22-25)
First, using raw materials not containing N, sample No. In the same manner as in Example 1, metal powder was obtained.

  Next, Sample No. 1 was used except that this metal powder was used and the heating atmosphere of the firing conditions was changed to a mixed gas atmosphere of 50 vol% argon and 50 vol% nitrogen. A sintered body was obtained in the same manner as in Example 1. At this time, the content ratio of N contained in the sintered body was changed by appropriately changing the partial pressure of the nitrogen gas.

  Samples other than the production conditions other than those shown in Table 2 were sample Nos. A test piece was obtained in the same manner as in 1.

(Sample No. 26, 27)
First, using raw materials not containing N, sample No. In the same manner as in Example 1, metal powder was obtained.

  Next, Sample No. was used except that this metal powder was used. A test piece was obtained in the same manner as in 1.

(Sample No. 28, 29)
After the raw materials having the alloy compositions shown in Table 2 were melted in a high frequency induction furnace, the molten metal was poured into a mold to obtain cast bodies. Thereby, a test piece was obtained.

(Sample No. 30-32)
Except for the production conditions shown in Table 2, sample No. A test piece was obtained in the same manner as in 1.

(Sample No. 33-36)
After the raw materials having the alloy compositions shown in Table 2 were melted in a high frequency induction furnace, the molten metal was poured into a mold to obtain cast bodies. Thereby, a test piece was obtained.

(Sample No. 37-39)
When melting the raw material in a high frequency induction furnace, nitrogen gas was injected into the molten metal. At this time, the N content was changed by appropriately changing the injection time.

  Samples other than the production conditions other than those shown in Table 2 were sample Nos. A test piece was obtained in the same manner as in 1.

(Sample No. 40-45)
Except for the production conditions shown in Table 3, sample No. A test piece was obtained in the same manner as in 1.

  In each table, each sample No. Among these metal powders and test pieces, those corresponding to the present invention were shown as “Examples”, and those not corresponding to the present invention were shown as “Comparative Examples”.

2. 2. Evaluation of test piece 2.1 Measurement of total Si amount and content of Si contained as silicon oxide With respect to the test piece, the total amount of Si and the content of Si contained as silicon oxide were measured by a gravimetric method and ICP emission spectroscopy. The measurement results are shown in Tables 4-6.

2.2 Evaluation of crystal structure by X-ray diffraction method The test piece was subjected to crystal structure analysis by X-ray diffraction. And the crystal structure contained in the test piece was identified by collating the height and position of each peak contained in the obtained X-ray diffraction pattern with the database published on the ICDD card. Then, the ratio of the highest peak height among the peaks attributed to Co ₃ Mo when the highest peak height among the peaks attributed to Co was set to 1 was calculated. The calculation results are shown in Tables 4-6.

2.3 Evaluation of aspect ratio of vacancies, dendrite phase and crystal structure The cross section of the test piece was polished, and the obtained polished surface was observed with a scanning electron microscope to identify the region occupied by the voids on the observed image. And while measuring the average diameter of the area | region which a hole occupies (this is regarded as the average diameter of a hole), the ratio (area ratio) of the area which the hole occupies with respect to the total area of an observation image was calculated.

  In addition, by observing the obtained polished surface with a scanning electron microscope and confirming how much the dendritic structure is present on the observed image, the degree of presence of the dendrite phase is determined according to the following evaluation criteria. evaluated.

<Dendrite phase evaluation criteria>
◎: Dendritic phase is almost absent ○: Dendritic phase is slightly present (area ratio 10% or less)
Δ: Slightly more dendrite phase (over 10% to 20% area ratio)
X: A very large dendrite phase is present (area ratio is over 20%)

The obtained polished surface was observed with a scanning electron microscope, and the average value of the aspect ratio of the crystal structure was calculated on the observed image.
The above evaluation results are shown in Tables 4-6.

2.4 Measurement of Vickers hardness Vickers hardness was measured on the surface of the test piece. The measurement results are shown in Tables 4-6.

2.5 Evaluation of corrosion resistance 2.5.1 Evaluation of metal elution amount With respect to the test piece, the elution amount (elution amount per unit area) for each metal element was measured in accordance with the elution test method for metallic biomaterials defined in JIS T 0304. As a test solution, a solution in which 99 mL of ultrapure water was mixed with 1 mL of lactic acid was used. The pH of this solution was 2.3 and the temperature was 37 ° C. The amount of the solution used was an amount corresponding to 50 mL per 8 cm ² of the surface area of the test piece, and the test time was 7 days. And the measured result was evaluated based on the following evaluation criteria.

<Evaluation criteria for metal elution amount>
A: Elution amount of each metal element is very small (less than 0.5 μg / cm ² )
○: The elution amount of each metal element is small (0.5 μg / cm ² or more and less than 1 μg / cm ² )
Δ: Large amount of elution of each metal element (1 μg / cm ² or more and less than 2 μg / cm ² )
X: Elution amount of each metal element is very large (2 μg / cm ² or more)
The above evaluation results are shown in Tables 4-6.

2.5.2 Evaluation of resistance to seawater The test piece was evaluated according to the salt spray test method specified in JIS Z 2371. The sodium chloride concentration of the salt water used was 5 g / L. And the test piece was left for 24 hours in the environment sprayed with salt water at the temperature of 25 degreeC, and the presence or absence of the corrosion defect after a test was evaluated in accordance with the following evaluation criteria.

<Evaluation criteria for salt spray test>
◎: Corrosion area ratio is 0.1% or less ○: Corrosion area ratio is more than 0.1% and 1% or less △: Corrosion area ratio is more than 1% and 2.5% or less ×: Corrosion area ratio The above evaluation results are shown in Tables 4-6.

2.6 Measurement of 0.2% yield strength, elongation and Young's modulus The test piece was measured for 0.2% proof stress and elongation according to a test method for mechanical properties of a noble metal material for restoration of a dental metal ceramic prescribed in JIS T6118.

Further, the Young's modulus was obtained in accordance with a test method for a dental metal material defined in JIS T 6004.
The results of the above measurements are shown in Tables 4-6.

2.7 Evaluation of slipperiness Each sample No. First, 300,000 rubbing tests were performed on the test pieces.

  Next, the coefficient of static friction was measured for the surface subjected to the rubbing test. And the measured static friction coefficient was evaluated according to the following evaluation criteria.

<Evaluation criteria for friction coefficient>
A: The friction coefficient is extremely small (less than 0.5)
○: Friction coefficient is slightly small (0.5 or more and less than 0.6)
Δ: Slightly large friction coefficient (0.6 or more and less than 0.7)
X: Friction coefficient is extremely large (0.7 or more)
The above evaluation results are shown in Tables 4-6.

2.8 Evaluation of forgeability Sample No. About the test piece of 40-45, cold forging was performed using the metal mold | die for forging. And based on the following evaluation criteria, the forgeability of each test piece was evaluated based on the dimensional accuracy of the test piece after forging.

<Evaluation criteria for forgeability>
A: High forgeability (high dimensional accuracy)
○: Slightly high forgeability (slightly high dimensional accuracy)
Δ: Slightly low forgeability (slightly low dimensional accuracy)
X: Low forgeability (low dimensional accuracy)
The above evaluation results are shown in Tables 4-6.

As is clear from Tables 4 to 6, it was found that the test pieces corresponding to the respective examples were excellent in corrosion resistance and slipperiness. It was also found that the Vickers hardness was relatively high and the 0.2% proof stress and Young's modulus were relatively large.
Moreover, it was recognized that forgeability is enhanced by adding a predetermined amount of Ni.

3. Evaluation of relationship between N concentration and hardness First, each sample No. having the alloy composition shown in Table 7 was tested. 46-52 test pieces were produced.

  Next, each sample No. was measured in the manner described in “2.4 Measurement of Vickers Hardness”. The Vickers hardness of 46 to 52 test pieces was measured. The measurement results are shown in Table 7 and FIG.

  As is clear from Table 7 and FIG. 3, a relationship in which the hardness is minimized at a specific N concentration was recognized between the N concentration in the test piece and the Vickers hardness. When the hardness decreases, the wear resistance of the test piece is considered to increase. Therefore, a fastener component that enables a smooth opening and closing operation over a long period of time can be obtained by using a powder having a composition having a hardness close to the minimum value.

DESCRIPTION OF SYMBOLS 1 Slide fastener 11 Fastener tape 12 Element 13 1st fastener 14 2nd fastener 15 Slider 111 Fastener tape 111a Thin belt part 111b Core part 112 Fastener tape 112a Thin belt part 112b Core part 121 Fixing part 122 Engagement part 151 Slider body 152 handle

Claims (12)

Co is the main component,
Cr is contained in a proportion of 16% by mass to 35% by mass,
Mo is contained in a ratio of 3% by mass to 12% by mass,
Si is contained in a proportion of 0.3% by mass or more and 2.0% by mass or less,
N is included in a ratio of 0.09 mass% to 0.5 mass%,
A fastener component comprising a portion composed of a sintered body of metal powder. A part of the Si is included as silicon oxide,
The fastener component according to claim 1, wherein a ratio of Si contained in the Si as the silicon oxide is 20% by mass or more and 80% by mass or less.   The fastener part according to claim 2, wherein the silicon oxide is segregated at a grain boundary of the sintered body. In the X-ray diffraction pattern obtained by the X-ray diffraction method using CuKα rays, when the highest peak height among the peaks caused by Co identified based on the ICDD card is set to 1, it is based on the ICDD card. The fastener part according to any one of claims 1 to 3, wherein a ratio of the height of the highest peak among peaks attributed to Co ₃ Mo identified in the above is 0.01 or more and 0.5 or less.   The fastener component according to any one of claims 1 to 4, wherein a ratio (N / Si) of the content ratio of N to the content ratio of Si is 0.1 to 0.8 in terms of mass ratio.   The fastener part according to any one of claims 1 to 5, wherein Ni is contained in a ratio of 0.3 mass% to 15 mass%.   The fastener component according to any one of claims 1 to 6, wherein Fe is contained in a ratio of 0.3 mass% to 6 mass%.   The fastener component according to any one of claims 1 to 7, wherein Mn is contained in a ratio of 0.3 mass% to 3 mass%.   The fastener according to any one of claims 1 to 8, wherein the surface corrosion area ratio is 1% or less when subjected to a test for 24 hours in accordance with a salt spray test method defined in JIS Z 2371. parts.   The fastener part according to any one of claims 1 to 9, wherein the Vickers hardness is 200 or more and 480 or less. Co is the main component,
Cr is contained in a proportion of 16% by mass to 35% by mass,
Mo is contained in a ratio of 3% by mass to 12% by mass,
Si is contained in a proportion of 0.3% by mass or more and 2.0% by mass or less,
N is included in a ratio of 0.09 mass% to 0.5 mass%,
A metal powder for powder metallurgy, which is used for manufacturing fastener parts. Co is the main component, Cr is contained in a proportion of 16% to 35% by mass, Mo is contained in a proportion of 3% to 12% by mass, and Si is 0.3% to 2.0%. A step of forming a composition containing a metal powder that is contained in a proportion of not more than mass% and N is contained in a proportion of not less than 0.09 mass% and not more than 0.5 mass% by a metal powder injection molding method to obtain a molded body When,
Firing the molded body to obtain a sintered body;
The manufacturing method of the fastener components characterized by having.

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