JP2019069452A - Dissimilar material joined article, and method for producing dissimilar material joined article - Google Patents

Abstract

To provide a dissimilar material joined article in which the strength of the joined boundary faces of dissimilar materials with different thermal expansion coefficients is improved, and a method for producing a dissimilar material joined article capable of producing the dissimilar material joined article.SOLUTION: Provided is a dissimilar material joined article comprising: a first member; and a second member whose thermal expansion coefficient is higher than that of the first member, and joined with the first member. The first member has a projection in which a part of the surface of the first member is projected, and the second member is fitted to the projection in the joined face of the first member and the second member.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a dissimilar material joint and a method of manufacturing a dissimilar material joint.

  As a dissimilar-material joined product, generally, one obtained by filling a dissimilar material in the inner space of a container (outer container) is known. For example, a dissimilar material joint product in which a material different from the above-mentioned container is poured into the inside of a metal container and is cast is mentioned.

  In addition, there is known a dissimilar material bonded product obtained by providing a protrusion on the inner surface of a container and filling the container with a liquid metal by a casting method. In this dissimilar-material-joined product, since the container and the cast portion inside are fitted with each other at the projection, it is possible to provide a dissimilar-material joined product in which both are firmly connected.

  Patent Document 1 discloses an outer tube made of a carbon steel or low alloy steel at least one end opening cylindrical member having a hooking member protruding inward from the inner wall surface and an inner space portion of the outer tube. A heat- and wear-resistant liner is disclosed, characterized in that it consists of an internal filler made of cast-in-filled white iron.

JP-A-2-46966

  However, in the case of the dissimilar material joint described above, the inner cast part cast at high temperature shrinks in the process of cooling from high temperature, the interface between the container and the cast part peels off, and the joint interface between the outer container and the inner cast part There was a problem that a gap occurred. In particular, when the thermal expansion coefficient of the casting portion is larger than that of the container, the shrinkage of the casting portion in the cooling process is large, and thus a gap is likely to be generated at the bonding interface. When a gap is generated, the bonding strength between the two decreases. In Patent Document 1, no consideration is given to the prevention of the gap caused by the difference in the thermal expansion coefficient, and the strength of the bonding interface may not be sufficient.

  In view of the above-described circumstances, an object of the present invention is a dissimilar material joined product in which the strength of the bonding interface of dissimilar materials having different thermal expansion coefficients is improved and a dissimilar material joined product capable of producing such dissimilar material joined products. It is to provide a manufacturing method of

  In order to achieve the above object, the present invention has a first member, and a second member having a thermal expansion coefficient larger than that of the first member and joined to the first member, The first member has a protrusion from which a part of the surface of the first member protrudes, and the second member is fitted to the protrusion at the joint surface between the first member and the second member. To provide a dissimilar material joint product characterized by

  According to the present invention, there is provided a dissimilar material joint product in which the strength of the bonding interface of dissimilar materials having different thermal expansion coefficients is improved, and a method of manufacturing the dissimilar material joint product capable of producing such dissimilar material joint products. can do.

  Problems, configurations, and effects other than those described above will be clarified by the description of the embodiments below.

It is sectional drawing of the 1st member in a 1st Example. It is sectional drawing of the dissimilar-material joined article in 1st Example. It is an enlarged view of X part of FIG. It is sectional drawing of the dissimilar-material joined article in 2nd Example. It is an enlarged view of Y part of FIG. It is the elements on larger scale of the dissimilar-material joined article in 3rd Example. It is sectional drawing of the 1st member in 4th Example. It is sectional drawing of the dissimilar-material joined article in 4th Example. It is sectional drawing which shows the state which seal-welded the opening part of the dissimilar-material joined article in 4th Example. It is sectional drawing of the dissimilar-material joined article in 5th Example. It is a schematic diagram which shows the specific example (shaft) of the dissimilar-material joined article which concerns on this invention. It is sectional drawing of FIG. It is a schematic diagram which shows an example of a powder lamination modeling apparatus.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As described above, the dissimilar-material-bonded article according to the present invention has the first member, and the second member which has a thermal expansion coefficient larger than that of the first member and is joined to the first member. First, the first member will be described.

  FIG. 1 is a cross-sectional view of a first member in the first embodiment. As shown in FIG. 1, the first member 10 a includes an outer frame 11 and a protrusion 12. The protrusion 12 is a part of the surface of the outer frame 11 (first member 10 a) protruding. That is, the projections 12 are integral with the first member 10a, and are not attached to the first member 10a as members different from the first member 10a. The hooking material of Patent Document 1 described above is described to be attached to the inner wall of the outer pipe by welding, screwing or the like, and the hooking material is not a part of the surface of the outer pipe protruding. In FIG. 1, the first member 10a is a hollow cylinder having an opening at one end and a bottom at the other end, and projections 12 are provided on the inner surface (inner side and bottom) of the cylinder. ing.

  In order to obtain the first member 10a in which a part of the surface of the outer frame 11 protrudes, the present invention is also referred to as powder lamination molding method known as one of metal three-dimensional printers (hereinafter referred to as "layer molding method"). Use). Here, the powder laminate molding method will be described. FIG. 13 is a schematic view showing an example of a powder laminate molding apparatus. First, the metal powder 9 (raw material powder of the first member) in the supply tank 1 is supplied by raising the stage 2. The supplied metal powder 9 is supplied to the upper part of the shaping stage 8 by the movement of the roller 3. After supplying the raw material powder, the laser beam 5 oscillated from the laser oscillator 4 is reflected by the galvano mirror 6, the irradiation position is moved, and the metal powder 9 in a predetermined region is melted to obtain the solidified portion 7. Thereafter, the modeling stage 8 is lowered. By repeating this process, it is possible to manufacture a three-dimensional structure having a complicated shape.

  In FIG. 1, the direction of the arrow is the stacking direction, which is the movement direction of the modeling stage. The first member 10a manufactured by the additive manufacturing method is characterized by having a melt solidified structure. Further, in order to scan and solidify the laser light, the first member 10a has a linear pattern extending along the scanning direction of the laser light. This pattern can be observed by an optical microscope.

A portion of the protrusion 12a of the first member protrudes in a direction inclined with respect to a perpendicular (line indicated by α in FIG. 2) to the surface of the root of the protrusion 12, and inclines θ ₁ ° with respect to the α ray ing. Further, projections 12b provided on the bottom surface of the first member 10a is in theta ₃ ° or theta ₄ ° inclined with respect to the bottom surface. It is known that in powder layered manufacturing, θ ₁ , θ ₃ and θ ₄ can not be molded unless they are 20 ° or more.

  Next, the second member will be described. FIG. 2 is a cross-sectional view of the dissimilar material joint in the first embodiment. FIG. 2 shows the first member 10a of FIG. 1 joined to a second member 13 made of a material different from that of the first member 10a. In the present embodiment, the second member 13 is manufactured using a casting method. That is, the material of the second member 13 is heated and melted, and is filled and disposed inside the first member 10a and then cooled to produce the second member 13 joined to the first member 10a. be able to. In this way, it is possible to obtain a dissimilar-material joined product 100a in which the first member 10a and the second member 13 are integrated. The fitting strength of the two members can be greatly improved by fitting (engaging) the projections 12 of the first member into the second member 13. For this reason, even if the thermal expansion coefficient of the second member is larger than that of the first member, and the second member 13 contracts in the process of cooling the second member 13, the first member 10a and the first member 10a Peeling of the two members 13 can be prevented. In the patent document 1 mentioned above, it is not considered about the difference of the thermal expansion coefficient of a hook, an outer pipe | tube, and an internal filler.

The inclination angle theta ₁ of the protrusion 12 in Table 1 shows the relationship between the bonding strength of the first member 10a and the second member 13. We were examined tensile strength by changing the inclination angle theta ₁ of the projection 12a shown in FIG. As shown in Table 1, the bonding strength was low at inclination angles of 0 ° and 10 °, and was less at 20 MPa. On the other hand, at an inclination angle of 20 to 80 °, the bonding strength was high, and all were 60 MPa or more. In particular, the bonding strength was highest at an inclination angle of 45 °, and was 130 MPa. Therefore, the inclination angle theta ₁ is 20 to 80 ° is effective for securing the strength, and most preferably 45 °. In the powder layered manufacturing method, θ ₁ can not be less than 20 °. If the angle is greater than 80 °, the second member 13 will be difficult to fill.

  The shape and size of the protrusions are not particularly limited, and the bonding strength between the first member 10a and the second member 13 can be sufficiently enhanced, and the ease of filling the second member 13 is reduced. It is possible to make adjustments as appropriate, as long as it is not done. As an example, a cylindrical shape having a diameter of 1 mm and a length of 4 mm is preferable. There are an aspect in which a large amount is provided in small amounts and an aspect in which a large amount is provided in small amounts as the disposition of the projections, but both are equivalent in terms of bonding strength and manufacturability. An example of the shape of the protrusion will be described in detail later.

  The first member 10a and the second member 13 use materials having different thermal expansion coefficients. Specifically, a material having a thermal expansion coefficient larger than that of the first member 10 a is used as the second member 13. In the dissimilar material-bonded product according to the present invention, as described above, the second member 13 having a larger thermal expansion coefficient is fitted to the projection 12 of the first member 10a, and the first member 10a and the second member The bonding strength with the member 13 can be increased, and separation of the first member 10 a and the second member 13 can be prevented even when the second member 13 is contracted.

Table 2 shows the thermal expansion coefficients of various materials. As shown in Table 2, stainless steel, maraging steel and inconel alloy have a coefficient of thermal expansion of 1.3 × 10 ⁻⁵ / ° C. or less, and aluminum alloy, copper and resin have a coefficient of thermal expansion larger than them. In the present invention, a first member having a protrusion is provided by a lamination molding method using a material having a smaller thermal expansion coefficient such as stainless steel, and a material having a larger thermal expansion coefficient such as an aluminum alloy is melted. It is effective in the combination which arranges on the surface of the 1st member, cools, and joins.

In the present embodiment, stainless steel is used as the first member 10 a, and an aluminum alloy is used as the second member 13. The aluminum alloy contains 10% silicon in aluminum. This alloy has a low melting point and a good flow of molten metal, so that the root portion (outer frame 11) of the projection 12 can be sufficiently filled. The coefficient of thermal expansion of stainless steel is 1.0 × 10 ⁻⁵ / ° C., and that of aluminum alloy is 2.1 × 10 ⁻⁵ / ° C. Since the aluminum alloy constituting the second member 13 has a larger thermal expansion coefficient than the stainless steel constituting the first member 10a, the amount of contraction of the second member 13 is large when the second member 13 is cooled, A gap is generated between the first member 10 a and the second member 13. In order to prevent this gap, the projection 12 is provided with a slope. By inclining the protrusion 12, the second member 13 having a large thermal expansion coefficient shrinks in the direction of fixing the protrusion 12 at the time of cooling, so that the bonding strength between the first member 10a and the second member 13 is improved. Can.

  On the other hand, if the thermal expansion coefficient of the second member 13 is too small, a gap is generated between the second member 13 and the protrusion 12 during cooling, which is not preferable in terms of the strength of the protrusion 13 and the second member 13.

  The combination of materials constituting the first member 10a and the second member 13 is not limited to the stainless steel and the aluminum alloy described above. Any combination may be used as long as a material having a thermal expansion coefficient higher than that of the first member 10 a is selected as the second member 13. In the case where the first member 10a is copper, the thermal conductivity of copper is high, so that it is possible to obtain a dissimilar-material-bonded component in which the surface temperature of the first member 10a is uniform. When the first member 10a is an aluminum alloy or a resin, it is possible to obtain a lighter-weight different-material-bonded component.

  As described above, in the case where the dissimilar-material-bonded product 100a is obtained by heating and melting the material constituting the second member 13 and pouring it into the first member 10a, the melting point of the first member 10a is the second It is preferable to select the material which comprises the 1st member 10a and the 2nd member 13 so that it may become higher than the melting point of the member 13.

  FIG. 3 is an enlarged view of a portion X of FIG. The melting point of the stainless steel constituting the first member 10a is about 1380 ° C., and the melting point of the aluminum alloy constituting the second member 13 is about 580 ° C. Therefore, although the first member 10a is not melted even when the second member 13 is filled, the reaction layer 14 is generated between the first member 10a and the second member 13 because the temperature is high. Do. The reaction layer 14 is mainly an intermetallic compound of iron and aluminum. This compound is more brittle than the first member 10 a and the second member 13. Therefore, the smaller the thickness of the reaction layer 14, the higher the bonding strength. In order to make the reaction layer 14 thinner, a method of lowering the melting temperature when filling the second member 13 as much as possible, a method of shortening the charging time as much as possible, and a method of water cooling the outer surface of the outer frame 10 are effective. . The composition of the reaction layer can be analyzed by EDX (Energy Dispersive X-ray Spectroscopy).

  FIG. 4 is a cross-sectional view of the dissimilar material joint in the second embodiment. The dissimilar material-bonded article 100b according to the present embodiment is characterized in that the covering layer 15 is provided on the surface of the outer frame 11 of the first member 10b. In the present embodiment, a layer made of boron nitride (BN) is provided as the covering layer 15. A coating 15 made of boron nitride is coated on at least the inner surface of the first member 10 b and then the second member 13 is filled. FIG. 5 is an enlarged view of a Y portion of FIG. By providing the covering layer 15 between the first member 10 b and the second member 13, the formation of the reaction layer 14 described in the first embodiment is prevented, and the first member 10 b and the second member 13 Bonding strength can be increased. As a result, it is possible to obtain a high strength dissimilar material joined product 100b.

As the covering layer 15, ceramics having high corrosion resistance such as alumina (Al ₂ O ₃ ), silicon carbide (SiC) and silicon nitride (Si ₃ N ₄ ) can be used other than boron nitride. These coating layers can be formed by electroplating, electroless plating, or the like. In addition, although the covering layer 15 is provided on the inner surface of the first member 10b in FIG. 4, it may be provided at a portion where at least the first member 10b and the second member 13 are in contact with each other. It may be provided also on the outer surface of the member 10b.

  FIG. 6 is a partially enlarged view of the dissimilar material joint in the third embodiment. The first member 10c according to the present embodiment is characterized in that a plating layer 16 is further provided on the surface of the covering layer 15 of the second embodiment. In the present embodiment, a chromium plating layer is applied as the plating layer. By forming the plating layer 16 on the entire surface of the outer frame 11 in this manner, the corrosion resistance of the first member is improved. Also, when the second member 13 is an aluminum alloy, chromium is less likely to react with the aluminum alloy, so the reaction layer generated between the first member and the second member 13 can be made thinner, too. High strength dissimilar material joint parts can be obtained.

  FIG. 7 is a cross-sectional view of the first member in the fourth embodiment. The first member 10d of the present embodiment differs from the first member 10a of the first embodiment in that the opening 20 is provided at the bottom.

  FIG. 8 is a cross-sectional view of the dissimilar-material-bonded article in the fourth embodiment. When the second member 13 is made of copper, the surface tension at the time of melting may be high, and the flow of the molten metal may be deteriorated. In such a case, by providing the opening 10, the filling property is improved and the vacuum is reduced. Even if not, the filling of the second member 13 is facilitated.

  FIG. 9 is a cross-sectional view showing a state in which the opening of the dissimilar material joint in the fourth embodiment is sealed and welded. As shown in FIG. 9, after filling the second member 13, a sealing plate 21 is provided at the opening on the filling port side, and a sealing plug 22 is attached to the opening 20 at the bottom of the first member 10d. Alternatively, sealing may be performed by the butt weld portion 23 and the fillet weld portion 24, respectively. When the first member 10d and the second member 13 are a combination of different materials (metals), the corrosion potential is different between the respective materials, and therefore corrosion occurs in the portion where the joint portion is exposed to the atmosphere It is easy to promote, but corrosion can be prevented by sealing such a portion that is susceptible to corrosion. This structure is particularly effective when used in corrosive environments.

FIG. 10 is a cross-sectional view of a dissimilar-material-bonded article in the fifth embodiment. In this embodiment, the shapes of various protrusions are shown. The protrusions 25 have an inverted trapezoidal cross section. Also, like the projection 26, the cross-sectional shape may be a V-shape. The protrusions 27 are shaped to project in an arc shape. The projections 26 and 27 can be manufactured by the additive manufacturing method if they are 20 ° or more with respect to the perpendicular (α ray) to the surface of the root of the projections, and the projections 25 have θ ₆ and θ ₇ of 20 ° or more. For example, it can be manufactured by the additive manufacturing method. The same effects as in Example 1 can be obtained with any of the protrusions. As a result, the bonding strength between the first member 10 and the second member 13 can be further improved.

In this embodiment, a specific product example of the dissimilar material joint is shown. FIG. 11 is a schematic view showing a specific example (shaft) of the dissimilar material bonding product according to the present invention, and FIG. 12 is a cross-sectional view of FIG. The shaft (lightweight impeller) 30 shown in FIG. 11 is a component of a pump that raises the flow velocity of the liquid by rotating at high speed. The shaft 30 is composed of a shaft core 31, a wing fixing portion 32 and a wing 33. By rotating the shaft 30 at high speed, the flow velocity of the liquid can be increased. In the present example, the wing fixing portion 32 and the wing 33 were manufactured by the additive manufacturing method. The material is inconel alloy. The shaft core 31 is an aluminum casting AC4C manufactured using an aluminum alloy. Although the additive manufacturing method uses powder as a raw material, the cost is high because the powder is expensive. In addition, the shaping speed is as slow as 10 to 50 cm ³ / hr, and the production takes time. The cost can be reduced and the manufacturing time can be shortened by limiting the portion to be formed by the additive manufacturing method to the wing fixing portion 32 and the wing 33 as in the present embodiment. And since the shaft core 31 with a large volume can be manufactured by the casting method which is inexpensive and has a short manufacturing time, the shaft 30 can be manufactured at a low cost and in a short time by this combination.

In addition, when the liquid with which the shaft 30 is in contact is crude oil or the like, it is necessary to use a material with good corrosion resistance on the surface in contact with the liquid. Inconel alloys are nickel-based alloys and are known to have very good corrosion resistance. Therefore, an inconel alloy is used for the wing fixing portion 32 and the wing 33, and an inexpensive aluminum casting is used for a portion not in contact with the crude oil. However, although the thermal expansion coefficient of Inconel alloy is 1.3 × 10 ⁻⁵ / ° C., the thermal expansion coefficient of AC 4 C is 2.1 × 10 ⁻⁵ / ° C. AC4C has a lower coefficient of thermal expansion and a larger shrinkage in the process of cooling from a high temperature. Therefore, in the method of casting the shaft core 31 inside the wing fixing portion 32, there is a problem that the bonding strength decreases. Therefore, as shown in FIG. 12, the projection 34 is provided on the inner surface of the wing fixing portion 32 at an angle of 45 ° with respect to the surface perpendicular to the surface of the wing fixing portion 32 to fix the wing 31 to the wing 31. The bonding strength with the portion 32 can be increased, and the shaft 30 can be rotated at high speed.

  In addition, although the melting point of Inconel alloy is about 1300 ° C., the melting point of aluminum alloy AC4C is about 580 ° C., and the inconel alloy has a higher melting point. Thus, by selecting a material having a high melting point as a member manufactured by the additive manufacturing method, the aluminum alloy is not melted even if it is cast, so the thickness of the reaction layer 15 shown in FIG. Can.

  As described above, according to the present invention, a dissimilar material joined product in which the strength of the bonding interface of dissimilar materials having different thermal expansion coefficients is improved, and a method for producing such dissimilar material joined product capable of producing such dissimilar material joined products It has been proven to provide.

  In addition, the above-mentioned Example is concretely described in order to help an understanding of this invention, and this invention is not limited to providing all the demonstrated structures. For example, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Furthermore, with respect to a part of the configuration of each embodiment, it is possible to delete, add to other configurations, and add other configurations.

  For example, although the shaft used for a pump was mentioned as an example as a specific example of the dissimilar-material joined article which concerns on this invention in the said description, it is applicable also to the shaft of a compressor and a refrigerator, or a water-cooled inverter.

DESCRIPTION OF SYMBOLS 1 ... supply tank, 2 ... stage, 3 ... roller, 4 ... laser oscillator, 5 ... laser beam,
DESCRIPTION OF SYMBOLS 6 ... Galvano mirror, 7 ... coagulation | solidification part, 8 ... modeling stage, 10a, 10b, 10c, 10d ... 1st member, 11 ... outer frame, 12, 12a, 12b, 25, 26, 27 ... processus | protrusion, 13th ... 2 members 14 reaction layers 15 coating layers (coating layers) 16 plating layers 20 openings openings 21 sealing plates 22 sealing plugs 23 24 welds 30 shafts , 31 ... axial core, 32 ... feather fixing part, 33 ... feather, 100a, 100b, 100c, 100d ... dissimilar material joined product.

Claims (20)

A first member, and a second member having a thermal expansion coefficient larger than that of the first member and joined to the first member,
The first member has a protrusion from which a part of the surface of the first member protrudes,
A dissimilar-material-joined article characterized in that the second member is fitted to the projection in the joint surface of the first member and the second member.   The dissimilar material joint according to claim 1, wherein the projection protrudes in a direction inclined with respect to a perpendicular to the surface.   The dissimilar material joining article according to claim 2, wherein an angle formed between the projection and the perpendicular is not less than 20 ° and not more than 80 °.   The dissimilar material joining article according to claim 2, wherein an angle between the projection and the perpendicular is 45 degrees.   The first member is a hollow cylinder having an opening at one end and a bottom at the other end, and the projection is provided on the inner surface of the cylinder. Bonded dissimilar materials as described.   The dissimilar material joining article according to claim 1, further comprising a coating layer provided on the surface of the first member.   The dissimilar-material-joined article according to claim 5, further comprising: an opening portion provided in a part of the bottom portion; and a sealing portion sealing the opening portion.   The said 1st member consists of stainless steel, maraging steel, or an inconel alloy, The said 2nd member consists of aluminum alloy, copper, or resin, It is any one of the Claims 1 thru | or 7 characterized by the above-mentioned. Dissimilar material joint product.   The dissimilar material joining article according to any one of claims 1 to 7, wherein the first member has a melt-solidified structure.   The dissimilar material joined article according to any one of claims 1 to 7, wherein the dissimilar material joined article is a shaft that constitutes a compressor, a pump or a refrigerator, or a water-cooled inverter. Preparing two materials having different coefficients of thermal expansion;
Manufacturing a first member by powder lamination molding method using a powder of a material having a smaller thermal expansion coefficient among the materials;
Heating and melting the other of the materials, disposing on the surface of the first member, and cooling to produce a second member joined to the first member;
The first member has a protrusion from which a part of the surface of the first member protrudes,
A method of manufacturing a dissimilar-material-joined article, wherein the second member is fitted to the projection at a joint surface of the first member and the second member.   The method according to claim 11, wherein the projection protrudes in a direction inclined with respect to a perpendicular to the surface.   The method according to claim 12, wherein an angle formed between the protrusion and the perpendicular is not less than 20 ° and not more than 80 °.   The method according to claim 12, wherein an angle between the projection and the perpendicular is 45 °.   The first member is a hollow cylinder having an opening at one end and a bottom at the other end, and the projection is provided on the inner surface of the cylinder. The manufacturing method of the dissimilar-material joined article of description.   The method according to claim 11, further comprising the step of providing a covering layer on the surface of the first member.   The method according to claim 15, further comprising the steps of: providing an opening in a part of the bottom; and sealing the opening.   The first member is made of stainless steel, maraging steel or inconel alloy, and the second member is made of aluminum alloy, copper or resin. Method of manufacturing dissimilar material joint products.   The method according to any one of claims 11 to 17, wherein the first member has a melt-solidified structure.   18. The method for producing a dissimilar material joined article according to any one of claims 11 to 17, wherein the dissimilar material joined article is a compressor, a pump or a shaft of a refrigerator or a water cooled inverter.

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