JPS5996272A - Formation of reinforced layer on metallic surface - Google Patents

Abstract

PURPOSE:To form easily a reinforced layer having excellent resistance to wear and heat on the surface of a metal in a short time by forming a ceramic fiber layer on the surface of the metallic base material and heating and melting the joining part thereof thereby forming a composite layer. CONSTITUTION:A metallic base material 5 is erected in the central part of a ceramic crucible 7, and ceramic fibers 6 are packed in the space between the material 5 and the crucible 7, thereby forming a ceramic fiber layer 8 on the surface in the lateral part of the material 5. A high-frequency induction coil 9 is spirally and uniformly formed along the circumferential direction on the outside of the crucible 7. The assembly is installed in a high-frequency induction furnace and is heated instantaneously by applying high-frequency current of a prescribed frequency thereto. Then, only the outside surface of the material 5 is heated to a high temp. by the skin effect of the eddy current generated in the material 5 and only the joining part with the layer 8 is melted, whereby a composite layer 10 mixed with the ceramic fibers is formed on the surface of the material 5.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a method for forming a reinforcing layer on a metal surface, and in particular, a method for forming a reinforcing layer on a metal surface, in particular, heating and melting a multi-metal surface by high-frequency induction heating to form a bond between the surface metal of the base material and ceramic fibers. The present invention relates to a method for forming a reinforcing layer on a metal surface by forming a composite layer containing a mixture of the following.

[Technical background of the invention and its problems]

In general, methods for strengthening gold M and N surfaces that improve the corrosion resistance and wear resistance of metal surfaces include carburizing, which involves diffusing and infiltrating carbon into the heated base metal surface, and carburizing, which diffuses and infiltrates nitrogen. Known methods include the tactoid method, which coats the surface with chromium metal, and the chrome plating method, which coats the surface with chromium metal. These strengthening methods mainly use carbon steel as the base material, and cannot be applied to other metals such as aluminum alloys.

On the other hand, methods for strengthening the surface of metals such as aluminum alloys include coating the surface of the base material by flame spraying or plasma spraying, for example. Reinforced plastic coating methods have been adopted in which materials are coated with A-quality plastic, but in the former thermal spraying method, the adhesion strength is relatively weak because the bonding with the base material is based on mechanical bonding due to the throw effect. There is a problem of this peeling off, and the latter reinforced plus snack coating method has good wear resistance, but because the coating material is resin, it has poor heat resistance, and the coating material deteriorates at high temperatures. There was a problem.

In addition, in recent years, 5iaN4 has been developed as a metal strengthening method that can be applied not only to aluminum alloys but also to general metals such as carbon steel, and has excellent wear resistance and heat resistance. SiC, At
A method for manufacturing metal-based composite materials using ceramic fibers such as 20a has been developed.

This metal-based composite material (Fiber Reinforce
d Metal) (hereinafter referred to as "FRMJ") has been widely used in the automobile industry, for example, because it exhibits excellent properties in terms of surface bow abrasion resistance and heat resistance, as described above, and is used in parts such as pistons and connecting rods. This is being studied to reduce the weight and improve the performance of automobiles.

For example, in order to manufacture a piston using FRM, ceramic fibers such as SiC fibers are cut into small pieces, mixed into molten aluminum alloy that will be the material for the piston, and stirred, and then placed in a mold to form the piston. In addition, as shown in FIG. 1, in order to strengthen only the ring groove part of the piston 1 that is most worn, the annular ring groove part 2 is molded in advance from FRM mixed with 5iC2Atzo3 fiber and magnesium alloy. This annular ring groove 2 is cast with aluminum alloy or magnesium alloy to form a piston.

Furthermore, in order to strengthen only the piston head 3, which is exposed to the highest temperature of the piston 1, as shown in FIG. The molded piston head 3 is put into a mold 4 and cast with magnesium alloy or the like to form a piston.

By the way, the conventional method described above has the following problems. First, the first method of casting a piston by mixing SiC fiber etc. into the bath water between the aluminum and ram and stirring it can strengthen the entire piston and has enough heat resistance to withstand high temperatures of 600C. However, it has the disadvantage that a large amount of expensive ceramic fibers are used, which necessitates a significant increase in costs.

In addition, in other conventional methods, a so-called hook-wrapping method is adopted in which the annular ring groove 2 or piston spatula (2) molded with FRM is wrapped.
(reinforcing material) had to be made in advance, which made the process complicated, took a lot of time, and was inconvenient for mass production.

[Purpose of the invention]

The present invention has focused on the above-mentioned problems and was devised to effectively solve them.The purpose of the present invention is to form a ceramic fiber layer on the surface of a metal base material, A metal whose abrasion resistance and heat resistance can be easily and quickly improved by heating and melting the joint part using high-frequency induction heating to form a composite layer of a mixture of surface metal and ceramic fibers. The present invention provides a method for reinforcing the surface layer.

[Embodiments of the invention]

A preferred embodiment of the method according to the present invention will be described in detail below with reference to the accompanying drawings.

3 to 7 are process diagrams for explaining a first embodiment of the method according to the present invention.

FIG. 3 shows a base material 5 to be strengthened, and this base material 5 can be made of steel materials such as iron-based alloys, as well as non-ferrous metal materials such as aluminum alloys and magnesium alloys. Aluminum alloys, etc., on which it is difficult to form a surface reinforcement layer, are preferable.

The shape of the motherboard 5 is, for the sake of explanation, molded into a cylindrical body, but it goes without saying that it is not limited to this shape. In particular, if the surface of the matrix 5 is angular, it is also composed of curves m with the same curvature.For example, a sphere or cylinder is better for forming a uniform surface reinforcement layer. be.

Figure 2 is a diagram showing ceramic fibers that will be used as composite materials in the future.
It is composed of short fibers, etc., and in particular, when the base material 5 is made of an aluminum alloy, S is used as a ceramic fiber.
The use of iC provides the best compatibility.

First, the base material 5 and the ceramic fiber as described above, ? , [
Ij 6 is loaded into a bottomed cylindrical ceramic crucible γ as shown in FIG. That is, the base material 5 is erected in the center of the crucible 7, the gap between the base material 5 and the crucible 7 is filled with the ceramic fibers 6, and the ceramic fibers are placed on the side surface of the cylindrical base material 5. Fiber Jg 8 is formed. Here, when filling the crucible 7 with ceramic fibers, it is preferable that the volume percentage of the fibers be 20 to 60%.

After the loading of the base material 5 and the ceramic fibers 6 is completed in this manner, a localized wave induction coil 9 is formed spirally and uniformly along the circumferential direction on the outside of the crucible 7.

This is then installed in a high frequency induction furnace (not shown),
A high-frequency current of a predetermined frequency is applied to heat the sample for 1 g. At this time, only the outer surface of the base material 5 is heated to a high temperature due to the skin action of the eddy current generated in the base material 5, and only the joint between this surface and the fiber layer 8, that is, only the base material surface is melted and the surface A composite layer 10 made of a mixture of metal and surrounding ceramic fibers is uniformly formed on the surface of the base material.

The material of the crucible 7 is not limited to ceramic materials, but any material may be used as long as it is not heated by high frequency induction.

In this way, after the heating and melting of the surface of the base material 5 is completed, the base material 5 is taken out from the crucible 7 and the surface of the base material 5 is made heat resistant and resistant, as shown in the partially enlarged sectional views of FIGS. 6 and 7. Formation of the reinforced composite layer 10 having abrasive properties and the like is completed.

The thickness t of the composite layer 10 formed here is usually about 1 mm, although it depends on the application of the product, and this thickness can be increased or decreased by changing the frequency of the high-frequency power source or changing the conduction time. Make sure to do it properly.

The metal (base material) on which this surface-strengthening layer has been formed can be used directly as a product without any other treatment, or if high precision is required, it can be finished by grinding. and make it into a product.

In this way, unlike the conventional casting method, there is no need to prepare the reinforcing material to be cast in advance, and the process is simple because the reinforcing composite layer can be formed directly on the metal base material whose shape has been completed. It's easy to do, and it can be done in a short amount of time.

In addition, parts (surface) that truly require wear resistance and heat regeneration properties.
It is possible to form a reinforced composite layer only on the material, which is economical and does not waste expensive ceramic fibers.
Moreover, the remaining ceramic fibers that are not mixed into the composite layer can be used again.

Incidentally, the metal base material manufactured by this method does not have to be used directly as a product, but can of course be applied to other parts as a reinforcing material for cast-in materials, for example.

Next, a second embodiment of the method according to the present invention will be described.

FIGS. 8 to 12 are process diagrams for explaining the second embodiment.

While the first embodiment formed a composite layer on the outer side of the cylindrical body, the present embodiment attempts to form a composite layer on the inner surface of the hollow cylindrical body like the ξ iso material.

As shown in the figure, 11 is a hollow cylindrical metal base material, such as a Tsuquibu.

As shown in FIGS. 9 and 10, this metal base material 11 is concentrically inserted into a so-called double-shaped crucible 13 having a hollow front body part 12 in the center. The gap between the inside of the material 11 and the center part 12 of the crucible 13 is filled with ceramic fibers 6 in the same way as in the first embodiment, and the inner surface of the cylindrical base material is A fiber layer 8 is formed thereon.

Next, this crucible has a hollow cylindrical body part 12 forming the center part of 13.
A high frequency conductor coil 14 is inserted into the inside, and this is instantaneously heated by ring tightening in a high frequency furnace. This heating causes the parent phase 1
Only the joint between the inner surface of the fiber layer 1 and the fiber layer 8, that is, the inner surface of the base material, is melted in the heating bath, and the surrounding ceramic fibers are mixed with this to form a composite layer 15 on the fiber surface as in the first embodiment. do.

By taking out the metal base material 11 from this crucible 13, a reinforced composite layer 15 having wear resistance and heat resistance is formed on the inner surface of the hollow cylindrical metal base material 11 as shown in FIGS. 11 and 12. It is possible to manufacture a finished product in which

Next, a third embodiment of the method according to the present invention will be described.

Figures 13 to 15 show the third fruit 2i'l! This is a process diagram for explaining Example i. In contrast to the second example in which the composite layer was formed only on the inner surface of a hollow cylindrical metal base material such as a pipe material, this example The aim is to form a composite layer not only on the surface but also on the outer surface at the same time.

As shown in FIG. 13, the ring 16 used in this embodiment has a hollow cylindrical body portion 16 in its center, as in the second embodiment.
It is molded into a so-called double structure with 7.
The hollow cylindrical metal base material 11 is inserted into the crucible 16 with its inner and outer surfaces spaced appropriately from the wall of the crucible 16.

Then, the second process is performed in the gap between the inner surface of the metal base material 11 and the hollow cylinder part 17 of the crucible 16, and in the gap between the outer surface of the metal base material 11 and the inner wall of the crucible. Similarly to the example, ceramic fibers 6 are filled to form concentric fiber layers 8.8 on the inner and outer surfaces of the base material 11, respectively.

Next, high-frequency induction coils 18, 18 are formed concentrically within the hollow cylindrical body 17 forming the center of the lever 16 and along the outer wall of the lever 16, respectively, and high-frequency waves are simultaneously applied to these coils. The inner and outer surfaces of the metal base material 11 are heated and melted to simultaneously form a composite layer 19.19. By taking out the gold scrap base material from the crucible 16, a finished product as shown in FIGS. 14 and 15 can be obtained.

Next, a fourth embodiment of the method according to the present invention will be described.

FIG. 16 is a perspective view showing a shift fork used in an automobile transmission, and FIGS.
The figure is a process chart for explaining the fourth embodiment.

This soft fork 20 is a part for sliding the synchronized mesh gear that rotates at high speed in the transmission. Because of the sliding contact, high button machinability is required.

To form a reinforcing composite layer on the lower end 21.21 of the fork 20, it is sufficient to carry out the same process as the cylindrical metal base material of the first embodiment, that is, as shown in FIGS. 17 and 18. As shown in the figure, the lower end 21 of the shift fork 20 is inserted into a cylindrical crucible 22 made of a ceramic material, and is supported and fixed in the gap between the lower end 21 and the inner wall of the crucible 22. is filled with ceramic fibers 6 to form a fiber layer 8. Then, by conducting high frequency waves to the high frequency fastening coil 23 provided in a pre-circular shape around the crucible 22, the surface of the lower end portion (base material) 21 of the shift fork is heated and melted as in the first actual measurement example. A reinforced composite layer 24 of this surface metal and ceramic fibers is then formed.

According to this example, it is possible to easily and quickly form a reinforced composite layer on the parts of the shift fork that require the most wear resistance, and also to create a shift fork that has dramatically superior stiffness and EA resistance compared to conventional ones. can be manufactured.

Next, a fifth embodiment of the method according to the present invention will be described.

FIGS. 19 and 20 are process diagrams for explaining the fifth embodiment.

In this embodiment, a reinforcing composite layer is formed in the piston manufacturing section (S25) where heat resistance and strength are most required in the piston.

When forming a composite layer on the screw head 25, the most important point is to ensure the thickness of the composite layer that can be formed on the head, as piston manufacturing requires a high I of 77 degrees. There is a point where it becomes necessary to control. Therefore, in this embodiment, pressure is applied to the piston every month, and when the piston moves a predetermined distance, the limit switch 26 stops applying pressure to form a composite layer of the desired thickness. .

Specifically, numeral 7 is an fHj-shaped crucible similar to that used in the first embodiment, the bottom of which is filled with a ceramic fiber layer 8 to an appropriate thickness. and,
The already molded piston 27 is inserted and placed on the fiber layer 8 in this crucible with its spatula P25 facing downward.

Next, as shown in FIG. 20, the piston rod 28 connected to the piston 27 is mounted on the press machine 29, and the piston spatula l in the base 30 that supports the crucible 7 is attached.
A high-frequency induction coil 31 is provided at a portion corresponding to the head 25, so that only the surface of the head 25 can be heated by high-frequency induction. Further, a limit switch 2 is provided at a predetermined interval from the tip of the arm 32 of the press machine 29 in the direction of its extension.
6 is provided so that the limit switch 26 stops this pressurization when the arm 32 extends a predetermined distance.

With the piston rod 28 deposited on the press machine 29 in this way, when high frequency waves are passed through the high frequency induction coil 31 to heat and melt only the surface of the piston head 25, the press machine 29 pressurizes it downward. As a result, the entire piston 27 gradually descends, and when it descends by a predetermined distance, the arm 32 contacts the limit switch 26 and pressurization is stopped. At this time, if the limit switch 26 and the power source of the high frequency induction coil 31 are connected, the high frequency power source can be cut off at the same time as the pressurization is stopped. In this way, the piston head 25 is
can be melted to form a composite layer 32 in which the surface metal and the ceramic fibers 8 are completely mixed.

Note that finishing processing may be performed as necessary.

Conventionally, the method used was to cast reinforcing material that had been manufactured in advance, so at least two casting processes were performed: one to manufacture only the reinforcement and one to finally manufacture the piston. However, according to this embodiment, only one casting is required to mold the piston, and the reinforced composite layer 32 can be easily and quickly applied to the piston 27 after the M-shape. In addition, it is possible to manufacture a piston that is lightweight, has excellent heat resistance, and is resistant to counterfeiting.

Next, a sixth embodiment of the method according to the present invention will be described.

FIG. 21 to FIG. 26 are process diagrams for explaining the sixth embodiment.

This embodiment forms a reinforcing composite layer in a ring groove in a piston where wear resistance is required, and particularly relates to a top ring groove where wear resistance is most required among ring grooves.

As shown in the figure, reference numeral 33 denotes a top ring groove portion having a rectangular cross section and formed along the circumferential direction of the head portion of the piston 34, which is a base material, and its depth and width are approximately 3 to 5 mm. ing.

Then, as shown in FIGS. 22 and 23, a groove cover 35 is attached to the piston head portion, which is divided into two in a semicircular arc shape so as to partially open the groove 33 and cover the entire portion 4a of the lever. The groove cover 35 is made of, for example, a ceramic material that has fire resistance and does not cause high frequency induction heating.

Once the groove cover 35 is attached in this manner, ceramic fibers 6 in the form of powder or short fibers are sequentially inserted and filled into the groove from the partially open portion 36 of the groove.

Here, as the piston material, for example, aluminum alloy,
Magnesium alloy or titanium alloy is used, and ceramic fibers such as Si3N4゜SiC or At
203 or the like is used, but especially when an aluminum alloy is used as the piston fiber, the compatibility can be improved by using SiC as the ceramic fiber.

When the filling of the ceramic fiber 6 is completed in this way, the vortex cover 3 as shown in FIG. 24 and FIG.
A cylindrical frequency induction coil 37 is spirally applied along the circumference of the groove 33, and a high frequency wave is applied to it to instantaneously melt the inner surface of the groove 33, thereby combining the surface metal with the ceramic fiber 6 filled in the groove. A reinforced composite layer 38 is formed by mixing the following.

Once the composite layer 38 with a thickness of about 1 mm is formed in this way, finishing is performed after punching to complete a piston as shown in FIG. 26.

The thickness of the composite layer 38 can be changed by changing the high frequency or by changing the conduction time.

Further, in the illustrated example, the composite layer 38 is formed only in the top ring groove 33, but the present invention is not limited to this, and the composite layer may be formed in all the grooves.

In the song, the grooved can body 35 is not limited to the one described above, and may be constructed as shown in FIG. 27, for example.

That is, a container-shaped groove cover 39 is formed in the entire piston navel P section including the ring groove 33 in close contact therewith, and a ceramic-based groove cover 39 that has been drilled in advance in correspondence with the ring groove 33 is formed. The fibers may be supplied into the groove from the fiber supply port 40.

As mentioned above, when only aluminum alloy is used as the piston material as in the past, it has a large coefficient of thermal expansion, so it is necessary to have a large gap between the piston and the cylinder, that is, the side clearance, so the oil There were problems in terms of consumption, energy efficiency, hitting sound, etc., but since the reinforced composite layer according to this example has a small coefficient of thermal expansion, it is possible to narrow the side clearance near the dots plan 1P, which solves the above problems. It's not just a fool's errand that can solve problems all at once, but it can also prevent problems such as blowholes and improve Ennon performance.

1-1 In the conventional cast-in method, manufacturing reinforcing material to be cast-in requires complicated processes and a lot of time, and 'rW
Although a large amount of +-valent ceramic fiber was required, Honji J
In the fii example, there is no need to pre-manufacture the Ifii reinforcement, and since the reinforcing composite layer is effectively formed only on the surface where wear resistance is most required, the amount of fiber used can be reduced. A piston with excellent wear resistance and heat resistance can be manufactured easily and inexpensively in a short time.

In the above-described embodiments, a method for forming a reinforcing layer on a piston, which is an automobile part, has been particularly described, but the present invention is not limited to this, and can be applied to any type of material that requires heat resistance and wear resistance. Of course, this method can be employed as a method for forming reinforcing layers of metals used in the field.

〔Effect of the invention〕

(1) By forming a reinforced composite layer of a mixture of surface metal and ceramic fibers (whiskers) on the surface of the metal matrix, a metal matrix with extremely excellent wear resistance and heat resistance can be produced. I can do it.

(2) Compared to the conventional cast-in method, less expensive ceramic fibers are used, making it economical. The process is simple and can be manufactured in a short time. .

(3) By applying the method of the present invention to a piston, it is possible to form a hardened surface layer with excellent durability, unlike the reinforced coating that could not be formed using the conventional bath additive method. .

(4) Since the side clearance of the piston can be reduced, oil consumption and hammering noise can be reduced, and energy efficiency can be improved, and since blow-through can be prevented, engine performance can also be improved.

(5) The apparatuses for implementing the method according to the present invention are also simple and can be easily implemented.

[Brief explanation of the drawing]

1 and 2 are longitudinal sectional views showing a piston manufactured by a conventional cast-in method, and FIGS. 3 to 7 are process diagrams for explaining the first embodiment of the present invention, Figure 3 is a perspective view showing the metal base material, Figure 4 is a perspective view showing ceramic fibers, Figure 5 is a perspective view showing the heating state by tri11)'J frequency induction heating, and Figure 6 is a perspective view showing the composite layer. FIG. 7 is a perspective view showing the formed base material, FIG. 7 is a cross-sectional view of a rotating part, and FIGS. 8 to 12 are process diagrams for explaining the second embodiment. FIG. 9 is a perspective view showing the heating state by high frequency induction heating, FIG. 10 is a plan view of the same, and FIG. 1.1 is a perspective view showing the base material on which the composite layer is formed. Figure 12 is the same plan view, Figures 13 to 15 are the third view.
FIG. 13 is a longitudinal cross-sectional view showing a state in which a metal base material is heated by high-frequency induction heating, and FIG. 1/I is a process diagram for explaining an example. Fig. 15 is a vertical leg r-plane view, Fig. 16 to Fig. 18 are process diagrams for explaining the fourth embodiment, and Fig. 16 shows the nft fork as the base material. Fig. 17 is a perspective view showing a state of heating by high-frequency induction heating;
Figure 8 is an enlarged vertical sectional view of the same, Figures 19 and 20 are process diagrams for explaining the fifth embodiment, and Figure 19 shows the state in which the piston, which is the base material, is installed in the crucible. A vertical cross-sectional view, FIG. 20 is a longitudinal sectional view showing a state of heating by high-frequency induction heating while pressurizing, and FIGS. 21 to 27 are process diagrams for explaining the sixth embodiment, Fig. 21 is a perspective view showing the ring groove of the piston head, Fig. 22 is a perspective view showing the groove body attached to the piston head, Fig. 23 is a longitudinal sectional view of the same part, and Fig. 24 is high-frequency induction heating. Fig. 25 is a cross-sectional view of the same W: sectional view, Fig. 26 is a longitudinal sectional view showing a state in which a composite layer is formed on the ring # part, and Fig. 27 is another groove cover. FIG. In addition, 5.11.20 and 25.33 in the figure are more null f than metal.
fJ: #, 6 i”L’ + Las S Tsuku series 41M,
1 (11 + 15 y19.24, 32.38 are composite layers. Patent applicant Nobuo Kinutani Patent attorney Isuso Jidosha Co., Ltd. Figure 5': 21itj Figure 8 Figure 89 Figure 1゜Figure 11 Fig. 13 Fig. 14 S, :,, Fig. 16 Bow 3 Fig. 19 Fig. 20/εN21 Fig. 24/=:)q Fig. 26:) (-,; City, i-E TF Town 4 (Voluntary) August 1982
Kazuo Wakasugi, Commissioner of the Japan Patent Office, January 11, 1999, Case Indication, Patent Application No. 57-206069, 2,
Title of invention Method for forming reinforcing layer on metal surface 3, Nichij
F′? Relationship with the person's case Patent applicant (017) Isuzu Motors Co., Ltd. 4, Agent post office number 105 1-6-7 Atago, Minato-ku, Tokyo (self-initiated) 6. Subject of amendment ηIll; r3 (Details of the Invention 111 Explanation section) and Drawing 7, contents of amendment (1) Specification FR page 7 line 7 "Figure 2" is corrected to "Figure 4". (2) The drawing, Figure 27, has been corrected as shown in the attached corrected drawing. 8. Catalog of ``J'' tEt types

Claims (5)

[Claims] (1) A ceramic fiber layer is formed on the surface of a base material such as metal, and the joint between the surface of the base material and the fiber layer is heated and melted to bond the surface metal of the base material and the ceramic fibers. A method for forming a reinforcing layer on a metal surface by forming a composite layer containing a mixture of. (2) A method for forming a reinforcing layer on a metal surface according to claim 1, wherein the heating melting or high-frequency induction heating is used. (3) Claim 1, wherein the base metal is an aluminum alloy, a magnesium alloy, or an iron-based alloy.
The method for forming a reinforcing layer on a metal surface according to item 1 or 2. (4) The ceramic fiber layer is made of Si3N4, Si
A method for forming a reinforcing layer on a metal surface according to claim 1 or 2, wherein the reinforcing layer is abraded by C or At203 whiskers. (5) The method for forming a reinforcing layer on a metal surface according to claim 1 or 2, wherein the metal is made of an aluminum alloy and the ceramic fiber layer is made of SiC whiskers.