JP2017087225A - Product manufacturing method and high-pressure piping manufactured by the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a product manufacturing method and a high-pressure piping which hardly causes cracking or peeling on an electroless nickel-phosphorus layer even when processing a substrate subjected to electroless nickel-phosphor plating.SOLUTION: An electroless nickel-phosphorus layer 14a of which a phosphorus content is 0.3 to 1.0% is formed on the surface of a cylindrical substrate 10b made of iron according to an electroless plating method. Subsequently, the substrate 10b formed of the electroless nickel-phosphorus layer 14a is subjected to heating processing at a temperature of 600 to 880°C and, thereby, a diffusion layer 14b is formed on a boundary part between the substrate 10b and the electroless nickel-phosphorus layer 14a. Then, the substrate 10b formed of the electroless nickel-phosphorus layer 14a and the diffusion layer 14b is subjected to plastic processing and, thereby, high-pressure piping 10 is formed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a product manufacturing method in which a base material having an electroless nickel-phosphorus layer formed on the surface thereof is plastically processed to form a predetermined product, and a high-pressure pipe manufactured thereby.

  2. Description of the Related Art Conventionally, plating for preventing corrosion has been applied to a portion of a high pressure pipe for sending fuel, cooling water, etc., or a part of a device used in water that comes into contact with liquid. Among such platings, there is electroless nickel-phosphorous plating that is excellent in wear resistance and that can form a plating layer having a uniform thickness on a substrate having a complicated shape by a simple method. In recent years, this electroless nickel-phosphorus plating has been used in various products and apparatuses (see, for example, Patent Document 1).

  In the product described in Patent Document 1, first, a plating object made of a metal material is degreased, and then electroless nickel-phosphorous plating is performed to form an alloy layer of nickel and phosphorus on the surface of the plating object. Forming. Next, the heat treatment temperature is selected according to the phosphorus content of the formed electroless nickel-phosphorous plating. For example, if a low phosphorus type electroless nickel-phosphorous plating alloy layer having a phosphorus content of 1% or more and less than 4% is formed, the heat treatment temperature is 500 ° C. or lower, preferably 350 ° C. or higher and 370 ° C. A temperature below 0 ° C is selected. And the product excellent in cavitation erosion resistance is obtained by heating a plating target object for about 1 hour at the selected heat processing temperature.

JP2012-87325A

  In the above-described product, electroless nickel-phosphorus plating is performed on a plating object formed in a product shape. However, some plating objects require processing after electroless nickel-phosphorus plating. For example, when attaching a nut to the central part of a high-pressure pipe whose outer diameter is larger than the outer diameter of the central part, attach the nut to the unprocessed pipe with the same overall outer diameter. In addition, it is necessary to compress the end portion of the pipe to increase the outer diameter to obtain a final high-pressure pipe shape. In such a case, it is difficult to apply electroless nickel-phosphorus plating to the high-pressure pipe to which the nut is attached. Further, when a plating object subjected to electroless nickel-phosphorous plating is processed by the above-described conventional method, there is a problem that the electroless nickel-phosphorous layer is easily cracked or peeled off.

  The present invention has been made to address the above-described problems, and its purpose is to provide a product in which the electroless nickel-phosphorous layer is not easily cracked or peeled even when a base material subjected to electroless nickel-phosphorous plating is processed. A manufacturing method and a high-pressure pipe manufactured thereby. In the description of each constituent element of the present invention below, the reference numerals of corresponding portions of the embodiment are shown in parentheses in order to facilitate understanding of the present invention. The present invention should not be construed as being limited to the configurations of the corresponding portions indicated by the reference numerals of the forms.

  In order to achieve the above-described object, the structural feature of the product manufacturing method according to the present invention is that the content of phosphorus is 0.3 on the surface of the base material (10b, 30b) made of metal by electroless plating. % To 1.0% of electroless nickel-phosphorus layer (14a, 24a) and a base material on which the electroless nickel-phosphorous layer is formed is heated at a temperature of 600 ° C. to 880 ° C. Then, a diffusion step (14b, 24b) is formed at the boundary between the base material and the electroless nickel-phosphorus layer, and the phosphorus (P) in the electroless nickel-phosphorous layer is aggregated and granulated. And a processing step of plastically processing the base material on which the diffusion layer is formed to form a predetermined product (10, 20, 30).

  In the product manufacturing method according to the present invention, the phosphorus content that is indispensable for performing electroless nickel-phosphorus plating is generally in the vicinity of the lowest value in the range of 1% or more and less than 4%, which is called low phosphorus. The value is 0.3% to 1.0% of extremely low phosphorus. Further, in the heating step, the heating temperature when the base material on which the electroless nickel-phosphorous layer is formed is heated at the melting point of the nickel-phosphorus alloy having a phosphorus content of 0.3% to 1.0%. It is set to 600 ° C. to 880 ° C. which is close to 900 ° C. The phosphorus content and heating temperature were obtained as a result of various experiments. According to this, after the heating process, the base material was plastically processed to form a predetermined product. Almost no cracking or peeling occurred in the nickel-phosphorus layer. For this reason, plastic processing can be performed after performing electroless nickel-phosphorous plating, and manufacturing of a product that requires processing after the electroless plating processing becomes extremely easy.

  Another structural feature of the product manufacturing method according to the present invention is that the heat treatment in the heating step is performed for 3 minutes to 120 minutes. According to this, even if the base material on which the electroless nickel-phosphorous plating layer is formed is plastically processed, the electroless nickel-phosphorous layer does not crack or peel off, and it has excellent corrosion resistance, which is the original purpose of plating. A product having an electrolytic nickel-phosphorus layer is obtained.

  Still another structural feature of the product manufacturing method according to the present invention is an iron pipe body in which the base material extends straight, and the terminal processing or base in which the product compresses the end of the base material to increase the outer diameter. It is a high-pressure pipe that has been bent so that the axial directions of both side portions of the material are different.

  As the metal on which the electroless nickel-phosphorous layer is formed, several kinds of metals can be used. Among them, iron easily forms an electroless nickel-phosphorous plating layer on the surface. In the present invention, since the high-pressure pipe is made of iron, it is possible to obtain a high-pressure pipe that is less likely to be cracked or peeled off in the electroless nickel-phosphorus layer after processing the base material and that has excellent corrosion resistance.

  Still another structural feature of the product manufacturing method according to the present invention is that, in the electroless plating step, an electroless nickel-phosphorous layer is formed on the inner surface and the outer surface of the substrate, and after the heating step, A zinc plating step of forming a zinc plating layer (25) on the surface of the electroless nickel-phosphorus layer on the outer surface is included.

  According to the present invention, when a pinhole is generated in the electroless nickel-phosphorus layer on the outer surface of the base material, it is possible to prevent the base material made of iron from being corroded. Since zinc has a higher ionization tendency than iron, when the galvanized layer comes into contact with a substrate made of iron through a pinhole, the galvanized layer is preferentially corroded and the substrate is corroded. To prevent it.

  The high-pressure piping according to the present invention is characterized in that the high-pressure piping manufactured using the above-described product manufacturing method is at least an electroless nickel-phosphorous layer of an electroless nickel-phosphorous layer and a diffusion layer. In addition, the nickel layer (N) includes a portion where the granular phosphorus (P) is scattered.

  In the electroless nickel-phosphorus layer formed on the surface of the substrate in the electroless plating process, phosphorus is distributed in a substantially uniform state in the nickel layer in the form of fine particles, but in the heating process according to the present invention. In at least the electroless nickel-phosphorous layer of the electroless nickel-phosphorous layer and the diffusion layer on the surface of the heat-treated base material, particulate phosphorus is aggregated and granulated. For this reason, at least in the electroless nickel-phosphorus layer, there are many portions composed only of nickel, and thus, even if the base material is plastically processed in the processing step, the electroless nickel-phosphorous layer is cracked or peeled off. Will not occur. As a result, a high-pressure pipe in which the electroless nickel-phosphorus layer on the surface is not cracked or peeled is obtained.

  Another structural feature of the high-pressure pipe according to the present invention is that the maximum value of the diameter of the granulated phosphorus is 1 μm to 3 μm.

  According to the present invention, a better high-pressure pipe can be obtained. Among the granulated phosphorus, there are various shapes such as a spherical shape, an ellipsoidal shape, and an oval shape. The diameter according to the present invention includes a diameter, a length, a width, and the like.

It is sectional drawing which showed the high voltage | pressure piping which concerns on 1st Embodiment of this invention. It is 2-2 sectional drawing of FIG. It is sectional drawing which showed the base material in which the electroless nickel phosphorus layer was formed. It is the structure | tissue photograph figure which expanded the boundary part of the base material of FIG. 3, and the electroless nickel phosphorus layer before heat processing. It is the photograph which expanded the boundary part of the base material of FIG. 2, and the plating layer formed by heat processing. It is the longitudinal cross-section which showed the state which attached the nut to the base material. It is sectional drawing which showed the state which terminal-processes a base material with a chuck | zipper and a punch. It is the longitudinal cross-sectional view which showed the high voltage | pressure piping which concerns on 2nd Embodiment of this invention. It is the perspective view which showed the high voltage | pressure piping which concerns on 3rd Embodiment of this invention. The edge part of the base material used by 3rd Embodiment is shown, (a) is sectional drawing which showed the state before compression processing, (b) is sectional drawing which showed the state after compression processing. It is the side view which showed the state before the bending process of the high voltage | pressure piping which concerns on 3rd Embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a high-pressure pipe 10 according to this embodiment. The high-pressure pipe 10 is used, for example, for supplying fuel to an engine in an automobile. The high-pressure pipe 10 is made of iron, and the main body 10a has an outer diameter of about 8 mm and a wall thickness of about 1.5 mm. A connection head 11 is formed at the end of the high-pressure pipe 10, and a nut 12 that cannot be removed from the high-pressure pipe 10 by the connection head 11 is attached to the outer periphery of the main body 10 a of the high-pressure pipe 10. .

  The connection head 11 is composed of an enlarged diameter portion 11a that gradually increases in diameter from the main body 10a side to the end side, and a sheet surface portion 11b that gradually tapers from the enlarged diameter portion 11a to the tip. . The nut 12 is formed in a substantially cylindrical shape that covers the connection head 11, and a thick portion 12 a is formed in the rear portion (on the right side in FIG. 1) with an insertion hole through which the main body 10 a can pass. A screw 12b is formed on the inner peripheral surface of the portion from the center to the front. The nut 12 is used when the high-pressure pipe 10 is connected to another connection member.

  A plating layer 14 is formed on the inner peripheral surface of the high-pressure pipe 10. As shown in FIG. 2, the plating layer 14 includes an electroless nickel-phosphorus layer 14a and a diffusion layer 14b. The diffusion layer 14b is a layer formed by a reaction between iron, which is a base material of the high-pressure pipe 10, and nickel and phosphorus of the electroless nickel-phosphorus layer 14a, and the ratio of the components gradually changes. . Therefore, there is no clear boundary between the electroless nickel-phosphorous layer 14a and the diffusion layer 14b, and the thickness of the plating layer 14 is about 10 μm to 25 μm as a whole.

  Next, an example of a method for manufacturing the high-pressure pipe 10 will be described. First, the electroless nickel-phosphorous layer 14a is formed on the inner surface of the cylindrical base material 10b (the portion excluding the nut 12 and the plating layer 14 in FIG. 6) before the high-pressure pipe 10 is plated and processed. An electroless plating process is performed. This electroless plating step is performed by immersing the base material 10b in a known plating solution, thereby forming an electroless nickel-phosphorous layer 14a having a thickness of 3 μm to 20 μm. The phosphorus content in the electroless nickel-phosphorus layer 14a is set to about 0.5%.

  Thereby, the cross-sectional shapes of the base material 10b and the electroless nickel-phosphorous layer 14a are in the state shown in FIG. FIG. 4 shows a structure photograph of the boundary portion between the base material 10b and the electroless nickel-phosphorous layer 14a shown in FIG. According to FIG. 4, the boundary between the base material 10b and the electroless nickel-phosphorous layer 14a can be clearly seen, and the particulate phosphorus P (the whitish part) in the nickel layer (the dark part) in the electroless nickel-phosphorous layer 14a. ) Are scattered in a substantially uniform state.

  Next, the heating process of heat-treating the base material 10b on which the electroless nickel-phosphorous layer 14a is formed on the inner surface is performed. Here, the base material 10b on which the electroless nickel-phosphorous layer 14a is formed is heated in a vacuum furnace at a temperature of 600 ° C. to 880 ° C., for example, about 750 ° C., for 3 minutes to 120 minutes, for example, about 10 minutes. As a result, the diffusion layer 14b shown in FIG. 2 is generated at the boundary between the base material 10b and the electroless nickel-phosphorous layer 14a. The diffusion layer 14b is formed by diffusing the electroless nickel-phosphorous layer 14a toward the inside of the base material 10b, thereby improving the adhesion between the base material 10b and the electroless nickel-phosphorous layer 14a. .

  In FIG. 5, the boundary part of the base material 10b after heat processing and the plating layer 14 is shown as the structure | tissue photograph expanded with the microscope. According to FIG. 5, it can be seen that the presence of the diffusion layer 14 b is recognized and large granular phosphorus P is scattered in the nickel layer N in an uneven distribution state. This is because the electroless nickel-phosphorus layer 14a is heat-treated, and the particulate phosphorus P shown in FIG. 4 is aggregated to be changed into the large granular phosphorus P shown in FIG. In the state of FIG. 4, since phosphorus P is present evenly throughout the electroless nickel-phosphorous layer 14a, the electroless nickel-phosphorous layer 14a is hard, but in the state of FIG. 5, the electroless nickel-phosphorous layer 14a. Therefore, the electroless nickel-phosphorous layer 14a has a softer structure than the electroless nickel-phosphorous layer 14a shown in FIG. The particle size (including diameter, width, and length) of phosphorus P in the electroless nickel-phosphorous layer 14a after the heat treatment was 1 μm to 3 μm at the maximum.

  Next, a processing step for processing the base material 10b after the electroless plating step and the heating step is performed. This processing step is a step of assembling the nut 12 to the base material 10b and forming the connection head 11 at the end of the base material 10b to form the high-pressure pipe 10 as a product according to the present invention. In this processing step, first, as shown in FIG. 6, the nut 12 is assembled to the outer periphery of the base material 10 b having the plating layer 14 formed on the inner surface. Next, with the nut 12 moved to the other end side of the substrate 10b, the tip of the substrate 10b is pressed in the axial direction using the chuck 15 and the punch 16 shown in FIG.

  The chuck 15 is provided with a small-diameter holding hole 15a for holding the base material 10b in a penetrating manner and a large-diameter holding hole 15b formed on the opening side in communication with the small-diameter holding hole 15a. The base material 10b is disposed in the small-diameter holding hole 15a with the end side protruding from the opening of the large-diameter holding hole 15b. Further, the punch 16 is provided with a recess 16a corresponding to the tapered portion of the connection head 11 (the sheet surface portion 11b and the front portion of the enlarged diameter portion 11a), and the punch 16 includes the recess 16a on the substrate 10b. The base material 10b is pressed in accordance with the front end portion.

  As a result, the tip of the base material 10b is compressed and plastically deformed, and the connection head 11 is formed, whereby the high-pressure pipe 10 is obtained. In this case, the tapered portion of the connection head 11 is formed by pressing against the recess 16a of the punch 16, and the rear portion of the enlarged diameter portion 11a of the connection head 11 is pressed against the large diameter holding hole 15b. Formed with. In this processing step, the plated layer 14 was not cracked or peeled off.

  Thus, in this embodiment, the base material 10b for manufacturing the high-pressure pipe 10 is made of iron, and the content of phosphorus P in the electroless nickel-phosphorous layer 14a formed on the inner surface of the high-pressure pipe 10 is 0. About 5%. The base material 10b on which the electroless nickel-phosphorous layer 14a was formed was heated at a temperature of 750 ° C. for about 10 minutes. The phosphorus content and heating temperature are set based on the hypothesis of the present inventors.

  That is, the hypothesis is that as the content of phosphorus P increases, the electroless nickel-phosphorous layer 14a becomes harder. Therefore, if the content of phosphorus P is decreased, the electroless nickel-phosphorous layer 14a becomes softer and is processed. “The occurrence of cracks and peeling is reduced.” In addition, “if the heating temperature at the time of heat treatment is increased, phosphorus P in the electroless nickel-phosphorous layer 14a is effectively aggregated and the electroless nickel-phosphorous layer 14a. The portion in which phosphorus P is not present increases, whereby an electroless nickel-phosphorous layer 14a free from cracking or peeling due to processing is obtained. As a result of manufacturing the high-pressure pipe 10 based on this hypothesis, the electroless nickel-phosphorus layer 14a was not cracked or peeled off. For this reason, after performing electroless nickel-phosphorus plating, the manufacture of a product that requires plastic working becomes extremely easy.

(Second Embodiment)
FIG. 8 shows a cross section of the main body 20a in the high-pressure pipe 20 according to the second embodiment of the present invention. In the high-pressure pipe 20, the plating layer 14 composed of the electroless nickel-phosphorus layer 14a and the diffusion layer 14b described above is formed on the inner surface, and the plating layer 24 and the galvanizing layer 25 are formed on the outer surface. . The plating layer 24 is formed in the same manner as the plating layer 14 and is composed of an electroless nickel-phosphorus layer 24a and a diffusion layer 24b. The plating layer 24 is formed simultaneously with the plating layer 14. The galvanized layer 25 is formed by a known electrogalvanizing method after the heating step, and has a thickness of about 13 μm. Moreover, a process process is performed after a galvanization process. About the structure of the other part of this high-pressure piping 20, it is the same as the high-pressure piping 10 mentioned above.

  Since the high-pressure pipe 20 according to the present embodiment is configured as described above, the inner surface is protected by the plated layer 14 and the outer surface is protected by the plated layer 24. Even if pinholes are formed in the electroless nickel-phosphorous layer 24a, the galvanized layer 25 prevents the high-pressure pipe 20 from being corroded. In addition, if the processing step is performed after the galvanizing step for forming the galvanized layer 25, the galvanized layer 25 may be cracked. Even in this case, the galvanized layer 25 exhibits corrosion resistance due to sacrificial corrosion. Therefore, cracking does not become a problem. Other functions and effects of the high-pressure pipe 20 are the same as the functions and effects of the above-described embodiment.

(Third embodiment)
FIG. 9 shows a high-pressure pipe 30 according to the third embodiment of the present invention. A connection head 31 is formed at the end of the high-pressure pipe 30, and a nut 32 that cannot be removed from the high-pressure pipe 30 by the connection head 31 is attached to the outer periphery of the main body 30 a of the high-pressure pipe 30. Yes. The main body 30a is bent into a curved state by bending. That is, the high-pressure pipe 30 is formed by compressing an end portion and bending a predetermined portion of the main body 30a.

  When manufacturing the high-pressure pipe 30, first, as shown in FIG. 10A, an electroless nickel-phosphorous layer is formed on the inner surface of the cylindrical base material 30 b in the same direction as in the first embodiment. A plating layer 14 composed of 14a and a diffusion layer 14b is formed. Next, similarly to the first embodiment, the tip of the base material 30b is pressed in the axial direction using a chuck and a punch (not shown) to form the connection head 31 shown in FIG. 10 (b). To do. Thereby, the base material 30b after the compression processing to which the nut 32 is attached has the shape shown in FIG.

  Next, the base material 30b in the state shown in FIG. 11 is bent into the shape of the high-pressure pipe 30 shown in FIG. This bending process is performed using a bending machine. As this bending machine, for example, a bending machine described in JP-A-10-128456 can be used. This bending machine includes a chuck for gripping the base end portion of the base material 30b, a bending roll in which a processing groove capable of arranging a portion to be bent of the base material 30b is formed on the outer peripheral surface, and the bending roll. A shim mold disposed on the distal end side of the substrate 30b and a pressure mold disposed on the proximal end side of the substrate 30b so as to face the bending roll are provided.

  The squeeze mold and the pressure mold each have a concave groove corresponding to the base material 30b. The base material 30b has one of the outer peripheral surfaces in contact with the processing groove of the bending roll across the shaft, and the other outer peripheral surface. Comes into contact with the groove of the squeeze type and the pressure type. And while rotating a bending roll and rotating a shim type | mold on the outer peripheral side of a bending roll in the same direction as a bending roll, the base material 30b can be processed into the shape of the high voltage | pressure piping 30. FIG. Thus, even if compression processing and bending were performed on the base material 30b on which the plating layer 14 was formed, cracking and peeling did not occur in the plating layer 14 of the high-pressure pipe 30 obtained. As a modification of the present embodiment, as shown in FIG. 8, in addition to the plated layer 14, a plated layer 24 and a galvanized layer 25 may be formed on the outer surface.

  The present invention is not limited to the above-described embodiment, and can be modified as appropriate. For example, in the above-described embodiment, the product is a high-pressure pipe, but the product according to the present invention is not limited to the high-pressure pipe, and is manufactured by plastic processing after forming an electroless nickel-phosphorus layer on the surface. Anything can be used. Further, each part constituting the high-pressure pipe described above can be changed within the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 10,20,30 ... High pressure piping, 10b, 30b ... Base material, 14a, 24a ... Electroless nickel- phosphorus layer, 14b, 24b ... Diffusion layer, 25 ... Zinc plating layer, N ... Nickel layer, P ... Phosphorus.

Claims (6)

An electroless plating step of forming an electroless nickel-phosphorous layer having a phosphorus content of 0.3% to 1.0% by an electroless plating method on the surface of a substrate made of metal;
While heat-treating the base material on which the electroless nickel-phosphorous layer is formed at a temperature of 600 ° C. to 880 ° C., a diffusion layer is formed at the boundary between the base material and the electroless nickel-phosphorous layer, A heating step of agglomerating and granulating phosphorus in the electroless nickel-phosphorus layer;
And a processing step of plastically processing the base material on which the electroless nickel-phosphorus layer and the diffusion layer are formed into a predetermined product shape.   The product manufacturing method according to claim 1, wherein the heat treatment in the heating step is performed for 3 minutes to 120 minutes.   The base material is an iron pipe body that extends straight, and the product is deformed so that the end direction of the base material is compressed to increase the outer diameter or the axial directions of both side portions of the base material are different. The product manufacturing method according to claim 1 or 2, wherein the product is a high-pressure pipe subjected to bending. In the electroless plating step, an electroless nickel-phosphorous layer is formed on the inner surface and the outer surface of the substrate,
The product manufacturing method according to claim 3, further comprising a galvanizing step of forming a galvanized layer on the surface of the electroless nickel-phosphorous layer on the outer surface of the base material after the heating step. A high-pressure pipe manufactured using the product manufacturing method according to any one of claims 1 to 4,
High-pressure piping in which at least the electroless nickel-phosphorus layer of the electroless nickel-phosphorus layer and the diffusion layer includes a portion in which the granular phosphorus is scattered inside the nickel layer.   The high-pressure pipe according to claim 5, wherein a maximum value of the diameter of the granulated phosphorus is 1 μm to 3 μm. )