JP5676808B1 - Co-base alloy for welding, filler metal and overlay metal parts - Google Patents

Abstract

A Co-base alloy for welding having excellent cavitation erosion resistance and fracture toughness values is provided. SOLUTION: By mass%, Ni: 3.5 to 4.5 is included as an essential additive element, and optional additive elements include Mn: 0.5 to 10.0, W: 0.5 to 7.5, A welding Co-base alloy including Fe: 1.0 to 30.0 and having a composition composed of Co and inevitable impurities is employed. The Co-based alloy of the present invention is excellent in cavitation erosion resistance, has a higher fracture toughness value than stainless cast steel, and can be used even at high stress sites. [Selection] Figure 2

Description

  The present invention relates to a Co-based alloy for welding, a filler metal, and a built-up metal member.

  In recent years, erosion due to cavitation of water turbine runners has been accelerated in hydroelectric power plants, and repair work for cavitation erosion parts has become important. Turbine runners are generally made of cast stainless steel, but SUS309 materials and sapphire-based filler materials are usually used as welding repair materials (welding materials) when repairing welding of cavitation erosion parts. ing.

  Here, as a feature of the SUS309 material which is a filler material, the weldability is excellent, but the fatigue strength of the weld metal portion is lower than that of the base material, and the cavitation erosion resistance is also lower than that of the base material. Further, as a feature of the symbiotic filler metal (for example, 13Cr-4Ni), since heat treatment after welding is required, workability is inferior, and since the weld defect is smaller than the casting defect, the fatigue strength is Although higher, cavitation erosion resistance is comparable to the base material of the turbine runner.

  By the way, as a welding material having excellent cavitation erosion resistance, a nickel (Ni) based alloy (for example, “Inconel 625 (registered trademark)”), a cobalt (Co) based alloy (for example, “Stellite (registered trademark)”, etc. ). The amount of cavitation erosion of these welding materials is about two-thirds for Inconel 625 and one-tenth or less for stellite when compared to SUS309 material.

  Thus, Co-based alloys such as stellite are attracting attention as welding repair materials for water turbine runners because they are excellent in cavitation erosion resistance. Patent Document 1 describes a welding material excellent in cavitation erosion resistance and wear resistance by preparing a component composition of a cobalt-based alloy.

Japanese Patent No. 2774520

  However, although the welding materials described in Stellite and Patent Document 1 have excellent cavitation erosion resistance, they have lower fracture toughness values than stainless cast steel, which is a base material of water turbine runners, and are difficult to apply to parts subjected to high stress. There was a problem of being.

  The present invention has been made in view of the above circumstances, and has an excellent cavitation erosion resistance and fracture toughness value, a Co-base alloy for welding and a filler material, and a built-up metal member welded and repaired thereby. The issue is to provide.

In order to solve this problem, the present invention employs the following configuration.
The invention according to claim 1 is mass%, Ni: 2.7 to 4.54, Mn: 1.5 to 10.0, Fe: 3.0 to 30.0, C: 0.03 to 0.00. 60, Si: 0.01~3.0, Cr: 7~40, Mo: 1.0~15.0, wherein the balance and having a component composition consisting of C o and unavoidable impurities Co based alloy for welding.

The invention according to claim 2, in mass%, Ni: 3.5 to 4.5 4, a welding Co-based alloy according to claim 1, characterized in that it comprises a.

The invention according to claim 3, in mass%, W: 0.5 to 7.5, which is a welding Co-based alloy according to claim 1 or 2, characterized in containing Mukoto.

The invention according to claim 4 is mass%, Ni: 2.7 to 4.54 , Mn: 1.5 to 10.0, Fe: 3.0 to 30.0, C: 0.03 to 0 .60, Si: 0.01~3.0, Cr: 7~40, Mo: 1.0~15.0, include, in Co-based alloy having a component composition and the balance being C o and unavoidable impurities It is a filler material characterized by being.

The invention according to claim 5, in mass%, Ni: 3.5 to 4.5 4, a filler material according to claim 4, characterized in that it comprises a.

The invention according to claim 6, in mass%, W: 0.5 to 7.5, a filler material according to claim 4 or 5, characterized in including Mukoto a.

The invention according to claim 7 is a filler metal made of a metal linear body that forms a weld alloy part by overlay welding, wherein the weld alloy part is in mass%, and Ni: 2.7-4. 54, Mn: 1.5-10.0, Fe: 3.0-30.0, C: 0.03-0.60, Si: 0.01-3.0, Cr: 7-40, Mo : 1.0 to 15.0, includes a filler material and the balance being Co-based alloy having a component composition consisting of C o and unavoidable impurities.

The invention according to claim 8 is the filler material according to claim 7 , wherein Ni: 3.5 to 4.54 is contained in mass%.

The invention according to claim 9, in mass%, W: 0.5 to 7.5, a filler material according to claim 7 or 8, characterized in including Mukoto a.

According to claim 1 0 invention, wherein said metal wire-like body, characterized in that consists of a tubular metallic portion forming the outer skin, and an alloy component adjuster inner filled in the tubular metal part Item 10. The filler material according to any one of Items 7 to 9 .

Claims includes 10 wt% or less, the balance being a Co-based alloy having a component composition consisting of Co and inevitable impurities: according invention in claim 1 1, wherein the tubular metal part, Fe 1 is a filler material according to 0.

The invention according to claim 1 2, the thickness of the tubular metal part is a filler material according to claim 1 0 or 1 1, characterized in that it is 0.25mm or less.

The invention according to claim 1 3, the diameter of the metal wire-like member is a filler material according to any one of claims 7 to 1 2 and less than 3.2 mm.

The invention according to claim 1 4, the diameter of the metal wire-like member is a filler material according to any one of claims 7 to 1 3, characterized in that it is 2.0mm or less.

Such invention in claim 1 5, the filler material to a cladding metal member including a welding alloy part formed by overlay welding, the weld alloy part, by mass%, Ni: 2.7-4 .5, 4, Mn: 1.5 to 10.0, Fe: 3.0 to 30.0, C: 0.03 to 0.60, Si: 0.01 to 3.0, Cr: 7 to 40, It is an overlay metal member characterized in that it is a Co-based alloy having a component composition including Mo: 1.0 to 15.0, and the balance being Co and inevitable impurities.

The invention according to claim 16, in mass%, Ni: 3.5 to 4.5 4, a cladding metal member according to claim 1 5, characterized in that it comprises a.

The invention according to claim 17, in mass%, W: 0.5 to 7.5, which is a cladding metal member according to claim 1 5 or 16, wherein the free Mukoto.

The welding Co-based alloy of the present invention has 3.5-4. A Co-based alloy having a component composition comprising 54 mass% of Ni, excellent in cavitation erosion resistance and fracture toughness. Therefore, the Co-based alloy for welding of the present invention can be used as a welding repair material for members made of cast stainless steel. Moreover, since the fracture toughness value is higher than that of stainless cast steel, it can be used for a portion to which high stress is applied.

  Since the filler metal of the present invention is mainly composed of the above-described welding Co-based alloy, it has excellent cavitation erosion resistance and a higher fracture toughness value than stainless cast steel. Therefore, the filler material of the present invention can be used as a welding repair material for a member made of cast stainless steel even for a portion subjected to high stress.

  Further, in the filler metal according to another aspect of the present invention, the weld alloy portion formed when overlay welding is a Co-based alloy having a component composition containing Ni as an essential additive element. It has excellent corrosion resistance and a higher fracture toughness value than stainless cast steel. Therefore, it can be used as a welding repair material for a member made of cast stainless steel even for a portion where high stress is applied.

  Furthermore, since the built-up metal member of the present invention includes a welded alloy portion formed when overlay welding is performed using the above-described filler material, it has superior cavitation erosion resistance and higher fracture than stainless cast steel. Provide toughness value. Therefore, the built-up metal member of the present invention can be used for a place where high stress is applied.

It is a figure which shows typically the packaging form of the filler material which is 3rd Embodiment to which this invention is applied. It is a cross-sectional schematic diagram of the filler material which is 3rd Embodiment to which this invention is applied. It is a systematic diagram for demonstrating the manufacturing method of the filler metal which is 3rd Embodiment to which this invention is applied. It is a systematic diagram for demonstrating the manufacturing method of the filler metal which is 3rd Embodiment to which this invention is applied. It is a perspective view for demonstrating the shape of the welding test body used in the Example of this invention. In the Example of this invention, it is a figure which shows the result of the volume reduction | decrease amount by the jet method using a cavitjet apparatus. In the Example of this invention, it is a figure which shows the result of the volume reduction amount by the stationary method using a magnetostriction vibration apparatus.

  Hereinafter, an example of an embodiment to which a Co-based alloy for welding, a filler metal, and a built-up metal member of the present invention are applied will be described in detail with reference to the drawings. In addition, in the drawings used in the following description, in order to make the features easy to understand, there are cases where the portions that become the features are enlarged for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. Absent. The configurations, materials, dimensions, and the like exemplified in the following description are merely examples, and the present invention is not necessarily limited thereto, and can be implemented with appropriate modifications without departing from the scope of the invention. It is.

<First Embodiment>
First, the configuration of a welding Co-based alloy according to an embodiment to which the present invention is applied will be described.
The Co-based alloy for welding according to this embodiment includes an essential additive element and an optional additive element in a range shown below, and the balance is roughly configured to have a component composition composed of Co and inevitable impurities. In the following description, “%” representing a composition component is “% by mass” unless otherwise specified.

  That is, as the component composition of the welding Co-based alloy of the present embodiment, specifically, the following aspects (1) and (2) are exemplified.

(1) 3.5-4. 54 includes a mass% of Ni as essential additive element, component composition and the balance being optional additive elements, Co and inevitable impurities.
(2) 2.7-4. 54 mass% of Ni and 0.5 to 10.0% by weight of Mn containing as essential additive element, component composition and the balance being optional additive elements, Co and inevitable impurities.

The essential additive elements in the welding Co-based alloy of the present embodiment include Ni in the aspect (1) and Ni and Mn in the aspect (2).
Examples of the optional additive element in the welding Co-based alloy of the present embodiment include C, Si, Mn, Cr, Mo, Fe, and W.
Furthermore, P, S, Cu etc. are mentioned as an unavoidable impurity in the Co base alloy for welding of this embodiment, for example.

  Next, the reason for limiting the component range of each composition in the Co-based alloy for welding of this embodiment will be described.

"C (carbon)"
C is useful as a constituent element of the M ₂₃ C ₆ type carbide that is the strengthening phase, and has an effect of suppressing grain coarsening due to the peening effect. When the C content is less than 0.03%, a sufficient amount of precipitation of carbide cannot be secured, and thus the above-described effects cannot be exhibited. On the other hand, if the C content exceeds 0.60%, the transition of C to the outside of the alloy occurs, which may cause embrittlement of the base material. Therefore, the C content is preferably 0.03 to 0.60%, and more preferably 0.10 to 0.20% in order to sufficiently exhibit the above effects.

“Si”
Si has the effect of improving the hot water flow. Here, in order to acquire the said effect of Si, Si is contained at least 0.01% or more. On the other hand, when the Si content exceeds 3.0%, the weldability is lowered. Therefore, the content of Si is preferably 0.01 to 3.0% or less, and more preferably 0.01 to 1.0% in order to sufficiently suppress the deterioration of weldability.

"Mn (manganese)"
Mn becomes S (sulfur) and MnS resulting from brittleness, and has the effect of preventing brittleness and improving the flow of hot water. Further, when added to a Co-based alloy, there is an effect of improving the cavitation erosion resistance of the Co-based alloy. Here, when the Mn content is less than 0.5%, this effect cannot be obtained. On the other hand, if the Mn content exceeds 10.0%, the weldability is lowered. Therefore, the Mn content is determined to be 0.5 to 10.0%. Further, the content of Mn is more preferably 1.5 to 2.5%.

“Ni”
Ni has the effect of improving the fracture toughness value when added to a Co-based alloy. Specifically, the content of Ni is set to 2.7-4. By setting the ratio to 54% , a Charpy impact value equal to or higher than that of a cast stainless steel product (for example, “SCS5” which is a martensitic stainless cast steel material) can be obtained in the Charpy impact test. Here, this effect cannot be exhibited when the Ni content is less than 2.7%. On the other hand, the content of Ni is 4. If it exceeds 54% , in the tensile strength characteristics (0.2% yield strength, tensile strength), in the case of a cast stainless steel product (for example, “SCS5”), 0.2% yield strength: 540 [MPa] or more, tensile strength: 740 [MPa] or more and the same degree as specified (JIS G 5121)) cannot be achieved. Moreover, since the effect mentioned above is acquired more notably, the content rate of Ni is 3.5-4. 54% is preferable.

“Cr”
Cr is an essential element for increasing the oxidation resistance, corrosion resistance and mechanical strength of the Co-based alloy. When the Cr content is less than 7%, the oxidation resistance decreases. On the other hand, if the Cr content exceeds 40%, the mechanical strength decreases due to the precipitation of the σ phase, which is a harmful phase. In addition, since the Co content in the Co-based alloy is reduced, the cavitation erosion resistance is reduced. Therefore, the Cr content is determined to be 7 to 40%. Moreover, since the effect mentioned above is acquired more notably, suppressing the fall of cavitation erosion resistance, the content rate of Cr is more preferably 23 to 27%.

"Mo (molybdenum)"
Mo is a solid solution strengthening element that is dissolved in the Co matrix and improves the mechanical strength of the matrix. When the Mo content is less than 1.0%, the above-described effects are not exhibited. On the other hand, when the Mo content exceeds 15.0%, the mechanical strength is reduced by σ phase precipitation. Therefore, the Mo content is determined to be 1.0 to 15.0%. Further, the Mo content is preferably set to 4.0 to 5.0% because the above-described effects can be more remarkably obtained while suppressing a decrease in mechanical strength.

"Fe (iron)"
When Fe is added to a Co-based alloy, it has the effect of imparting ductility and flexibility to the Co-based alloy and improving workability. This effect cannot be obtained when the Fe content is less than 1%. On the other hand, when the Fe content exceeds 30%, the Co content in the Co-based alloy is lowered, so that the cavitation erosion resistance is lowered. Therefore, the Fe content is determined to be 1 to 30%. Moreover, since the content rate of Fe can acquire the effect mentioned above more significantly, suppressing the fall of cavitation erosion resistance, it is preferable to set it as 3 to 10%.

"W (tungsten)"
W, like Mo, is a solid solution strengthening element that dissolves in the Co matrix and improves the mechanical strength of the matrix. Here, in order to acquire the said effect of W, W is contained at least 0.5% or more. On the other hand, if the W content exceeds 7.5%, the σ phase precipitation becomes significant and the manufacturability decreases. Therefore, the W content is determined to be 0.5 to 7.5%. Moreover, since the above-mentioned effect is acquired more notably, suppressing the fall of manufacturability, it is more preferable that the content rate of W shall be 0.5 to 2.5%.

"P (phosphorus), S (sulfur) and Cu (copper)"
P, S and Cu are classified as inevitable impurities in the welding Co-based alloy of this embodiment. It is desirable that the residual content of these inevitable impurities is as close to 0% as possible. Of these inevitable impurities, at least P is preferably suppressed to 0.03% or less, and S is suppressed to 0.015% or less.

  P and S lower the melting point and form a low-melting eutectic with Ni, so that the cracking sensitivity is increased. Therefore, it is desirable that the P content is 0.03% or less and the S content is 0.015% or less, and the respective residual contents are as close to 0% as possible. In addition, when the content rate of P or S exceeds the said range, it is preferable to perform a dephosphorization process or a desulfurization process, and to set it as the content rate within the said range.

As mentioned above, as Co-based alloy for welding of this embodiment, C: 0.10-0.20, Si: 1.0 or less, Mn: 1.5-2.5, Ni: 3.5-4. 54, Cr: 23-27, Mo: 4.0-5.0, Fe: 3-10, W: 0.5-2.5, with the balance being composed of Co and inevitable impurities Those are preferred.

Next, an example of the manufacturing method of the Co-based alloy for welding according to this embodiment will be described.
In the Co-based alloy for welding according to the present embodiment, each of the above-mentioned compositional components constituting the welding is vacuum-induced melting (hereinafter referred to as “VIM”), and the molten metal is poured into a predetermined mold and cast. Can be produced.

  The Co-based alloy for welding of this embodiment is excellent in cavitation erosion resistance and fracture toughness values. Specifically, the anti-cavitation erosion property is about 65% with respect to the erosion amount of SUS309 material, which is a conventional welding repair material, in the jet method using the cavitation jet test apparatus according to ASTM G134-95. Can be reduced. As for the fracture toughness value, a Charpy impact value equal to or higher than that of a stainless cast steel product (for example, SCS5) can be obtained in the Charpy impact test.

As explained above, the Co-based alloy for welding according to the present embodiment has 3.5-4. Co-based alloy having a component composition comprising 54 mass% of Ni, or as an essential additive element from 2.7 to 4. 54 a Co-based alloy having a component composition comprising a mass% of Ni and 0.5 to 10.0% by weight of Mn, has excellent resistance to cavitation erosion resistance. For this reason, it can use as a repair material for welding of the erosion part in the member made from stainless steel. In addition, the Co-based alloy for welding of this embodiment has a fracture toughness value equal to or higher than that of a general stainless cast steel product (for example, SCS5). Therefore, it can also be used for a portion where high stress is applied.

<Second Embodiment>
Next, an example of a filler metal that is an embodiment to which the present invention is applied will be described.
The filler material of this embodiment is a wire-like metal linear body mainly composed of the welding Co-based alloy of the first embodiment described above, and can be used for TIG welding and the like.

  That is, as the main component of the filler material of this embodiment, the following aspects (1) and (2) are specifically mentioned.

(1) 3.5-4. 54 includes a mass% of Ni as essential additive element, Co base alloy having a component composition and the balance being optional additive elements, Co and inevitable impurities.
(2) 2.7-4. 54 mass% of Ni and 0.5 to 10.0% by weight of Mn containing as essential additive element, Co base alloy having a component composition and the balance being optional additive elements, Co and inevitable impurities.

  In addition, about the reason for limitation of the composition and each component range in the filler material of this embodiment, since it is equivalent to the Co base alloy for welding of 1st Embodiment, the description is abbreviate | omitted.

Next, an example of the manufacturing method of the filler material of this embodiment is demonstrated.
The filler material of the present embodiment is obtained by vacuum induction melting (preparing step) the composition components constituting the welding Co-based alloy in the first embodiment described above, and injecting the molten metal into a predetermined mold, to produce an ingot. Can be produced by forming a wire (ingot forming step), drawing a member machined from the ingot (drawing step), and forming it into a wire shape.

  Since the filler material of this embodiment is mainly composed of the above-described welding Co-based alloy of the first embodiment, it has excellent cavitation erosion resistance and fracture toughness values. Therefore, it can be used as a repair material for welding erosion portions in stainless steel cast members. Moreover, since the filler material of this embodiment has a fracture toughness value higher than that of stainless cast steel, it can also be used for parts subjected to high stress.

<Third Embodiment>
Next, another example of the filler metal that is an embodiment to which the present invention is applied will be described.
FIG. 1 is a diagram schematically showing a packaging form of a filler material which is an embodiment to which the present invention is applied. The filler material of the present embodiment is a metal linear body that forms a weld alloy part by overlay welding. Specifically, as shown in FIG. 1, the filler material 1 of the present embodiment may be, for example, a welding wire in a packaging form in which a spool or a coil is wound around a spool 10 made of plastic or fiberboard. However, it may be in the form of a filler bar (solid wire).

  FIG. 2 is a schematic cross-sectional view of a filler metal according to an embodiment to which the present invention is applied. As shown in FIG. 2, the filler material 1 of the present embodiment is filled in a cylindrical metal part 2 that forms an outer skin and the inside of the cylindrical metal part 2 when the metal linear body is viewed in cross section. And an alloy component adjusting unit 3 made of an alloy powder.

  The cylindrical metal portion 2 is a coating made of a cylindrical metal that covers the periphery of the filler metal 1 that is a metal linear body in the axial direction. The cylindrical metal portion 2 is provided so that the alloy powder filled therein does not scatter. Moreover, the cylindrical metal part 2 should just be a structure where the alloy powder with which it filled is not scattered, and the structure with the seam along the axial direction of the filler material 1 may be on the surface, and there is no seam. It may be a structure (that is, a seamless structure).

  The metal which comprises the cylindrical metal part 2 is Co (cobalt). Moreover, it is preferable that the cylindrical metal part 2 contains 10 mass% or less of Fe (iron). Co containing 10 mass% or less of Fe improves workability such as ductility as compared with that of Co alone, so that the cylindrical metal part 2 is formed by using this to form the cylindrical metal part 2. It is possible to process the film thickness of the metal film constituting the thin film. Specifically, the thickness of the cylindrical metal part (film) 2 can be set to, for example, about 0.2 to 0.3 mm.

  The alloy component adjusting unit 3 is an aggregate of various alloy powders filled in the cylindrical metal unit 2. Here, the kind and addition amount of the alloy powder constituting the alloy component adjusting portion 3 are the same as those when the weld material portion is formed by melting the melt material 1 by TIG welding using the melt material 1, that is, in a cylindrical shape. When the metal part 2 and the alloy component adjustment part 3 are melted to form a weld alloy part, the composition is particularly limited as long as the component composition of the weld alloy part has the same component ratio as that shown below. It is not a thing. Therefore, as long as the component composition of the weld alloy part formed by the filler metal 1 is the same, an inexpensive alloy can be appropriately selected and used in combination.

  Here, the welded alloy part formed by melting the filler material 1 of the present embodiment includes an essential additive element and an optional additive element in the following range, and the balance has a component composition consisting of Co and inevitable impurities. It is roughly configured. That is, the following aspects are specifically mentioned as a component composition of the weld alloy part in this embodiment.

2.7-4. 54 mass% of Ni, comprising as essential additive element 0.5 to 10.0% by weight of Mn and 1.0 to 30.0 wt% of Fe, the balance being optional additive elements, Co and inevitable impurities Ingredient composition.

Ni, Mn, and Fe are mentioned as an essential addition element of the weld alloy part in this embodiment. Here, in the said aspect, Ni is 3.5-4. More preferably 54 in the range of mass%, more preferably Fe is in the range of 1.0 to 10.0 wt%.
Moreover, as an arbitrary additive element, C, Si, Cr, Mo, W etc. are mentioned, for example.
Here, in the said aspect, it is preferable that W is the range of 0.5-7.5 mass%, and it is more preferable that it is the range of 0.5-2.5 mass%.
Furthermore, examples of unavoidable impurities include P, S, and Cu.

  In addition, about the reason for limitation of the composition and each component range in the welding alloy part of this embodiment, since it is equivalent to the Co-base alloy for welding of 1st Embodiment and the filler material of 2nd Embodiment, the description is abbreviate | omitted. To do.

Next, an example of the manufacturing method of the filler material 1 of this embodiment is demonstrated.
Here, FIG.3 and FIG.4 is a systematic diagram for demonstrating the manufacturing method of the filler metal which is one Embodiment to which this invention is applied. As shown in FIGS. 3 and 4, first, a steel strip 32 (hereinafter referred to as “Co hoop material”) 32 made of a Co plate is pulled out from the reel 31 and cleaned by a cleaning device 33 (FIG. 3A). 4 (a)-(b)). Next, the Co hoop material 32 is formed into a U-shape by the U-shaped forming roll 34 (FIG. 3B). Next, after supplying the alloy powder 36 from the adding device 35 filled with the alloy powder so as to have a required blending amount in the opening of the U-shaped Co hoop material 32 (FIG. 4C), The open end of the Co hoop material 32 is aligned with the hermetic forming roll 37 and formed into a cylindrical shape (FIGS. 3C and 4D). Next, when a seamless structure is required, after performing high-frequency resistance welding (FIG. 4E), the melt material 1 is obtained by reducing the diameter in the wire drawing step (FIG. 4F). .

  By the way, in order to reduce the heat input at the time of welding with the filler rod (melt filler material) which consists of SUS309 material which is the conventional welding repair material, the diameter of the filler rod is generally φ2.4 mm or less. .

  However, since the above-mentioned stellite and the welding material described in Patent Document 1 are Co-based alloys, they are very hard and have low elongation, so that a member obtained by machining an ingot is drawn (drawing process). It was difficult. Specifically, the diameter of the filler rod obtained by the wire drawing process was limited to about φ3.2 mm. As described above, when the diameter of the filler rod is large, there is a possibility that the amount of heat input at the time of welding becomes large, that is, problems such as generation of high residual stress and carbide generation may occur.

  On the other hand, the filler material 1 of this embodiment forms a Co hoop material into a cylindrical shape to form a cylindrical metal portion 2, and fills the inside of the cylindrical metal portion 2 with alloy powder to adjust the alloy components. Since it is the structure set as the part 3, the limit with respect to the small diameter in a wire-drawing process is higher than Co base alloy. Therefore, the melt rod diameter of the filler material 1 of the present embodiment can be less than φ3.2 mm, and can also be φ2.0 mm or less. Therefore, the filler material 1 of this embodiment has an effect that the amount of heat input during welding can be reduced (for example, possible with a welding current of 200 A).

Moreover, as for the filler material 1 of this embodiment, the welding alloy part formed when overlay welding is performed is 2.7-4. Since the Co-based alloy having a component composition comprising 54 mass% of Ni, excellent in cavitation erosion resistance and fracture toughness. Therefore, it can be used as a repair material for welding erosion portions in stainless steel cast members. Moreover, since the filler material 1 of this embodiment has a fracture toughness value higher than stainless cast steel, it can be used also for a part to which high stress is applied.

<Fourth Embodiment>
Next, the built-up metal member which is one embodiment to which the present invention is applied will be described. The build-up metal member of the present embodiment includes a weld alloy portion formed by build-up welding of the filler material of the second embodiment or the filler material of the third embodiment described above.

  That is, as the component composition of the weld alloy part in the built-up metal member of the present embodiment, the following aspects (1) to (3) are specifically mentioned.

(1) 3.5-4. 54 includes a mass% of Ni as essential additive element, component composition and the balance being optional additive elements, Co and inevitable impurities.
(2) 2.7-4. 54 mass% of Ni and 0.5 to 10.0% by weight of Mn containing as essential additive element, component composition and the balance being optional additive elements, Co and inevitable impurities.
(3) 2.7-4. 54 mass% of Ni, comprising as essential additive element 0.5 to 10.0% by weight of Mn and 1.0 to 30.0 wt% of Fe, the balance being optional additive elements, Co and inevitable impurities Ingredient composition.

The essential additive elements of the weld alloy part in the present embodiment include Ni in the above aspect (1), Ni and Mn in the above aspect (2), and Ni, Mn and Fe in the above aspect (3).
Moreover, as an arbitrary additive element, C, Si, Mn, Cr, Mo, Fe, W etc. are mentioned, for example.
Furthermore, examples of unavoidable impurities include P, S, and Cu.

Moreover, as for the build-up metal member of this embodiment, more specifically, the said weld alloy part is C: 0.10-0.20, Si: 1.0 or less, Mn: 1.5-2.5. , Ni: 3.5-4. 54, Cr: 23 to 27, Mo: 4.0 to 5.0, Fe: 3 to 10, W: 0.5 to 2.5, with the balance being composed of Co and inevitable impurities Those are preferred.

  In addition, the component composition of the weld alloy part in the build-up metal member of this embodiment shall mean the component composition in the part in which the penetration from a base material does not arise. Specifically, a part far from the base material, such as the vicinity of the surface of the weld alloy part, can be mentioned.

  Moreover, since it is equivalent to the 1st-3rd embodiment about the composition of the welding alloy part in the build-up metal member of this embodiment, and the reason for limitation of each component range, the description is abbreviate | omitted.

  Specifically, the build-up metal member of the present embodiment is a water turbine runner made of stainless cast steel, a propeller of a high-pressure pump, etc., and the cavitation erosion part is the filler material of the second embodiment or the third embodiment. This is a member (welded repair product) that has been repaired by welding.

  As described above, since the build-up metal member of the present embodiment includes a weld alloy part formed when build-up welding is performed using the filler material of the second embodiment or the third embodiment described above, Excellent cavitation erosion resistance and higher fracture toughness value than stainless cast steel. Therefore, the built-up metal member of the present embodiment can be used for a place where high stress is applied.

  The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  Hereinafter, the effects of the present invention will be described in more detail by way of examples. In addition, this invention is not limited at all by the Example.

Example 1
As Example 1, the Ni content was 4. 54 mass% of filler rods (filler material) was prepared.
First, a Co plate wound around a steel strip reel was formed into a U shape with a U-shaped forming roll, and the inside thereof was filled with alloy powder, and then a sealing forming roll treatment was performed. Next, the filler rod of Example 1 was manufactured to a diameter of 2.0 mm by a wire drawing process (see FIGS. 1 and 2). Table 1 shows target values and measured values of the composition (mass%) of each component of the filler rod. The chemical composition of the filler rod was measured by C for combustion-infrared absorption, Si for absorptiometry, and Mn, Ni, Cr, Mo, Co, and Fe for ICP emission spectroscopy.

  As shown in Table 1, it was confirmed that a filler material (φ2.0 mm) having a hoop material on the outside and an alloy enclosed on the inside (φ2.0 mm), and a filler material that matches the target chemical composition can be produced. .

(Example 2)
A filler rod of Example 2 was produced in the same manner as in Example 1 except that the Ni content was set to 3.9% by mass in Example 1 described above. Table 2 shows the component composition of the filler rod of Example 2.

(Comparative Example 1)
In Example 1 described above, the filler rod of Comparative Example 1 was prepared in the same manner as in Example 1 except that the composition was equivalent to the Co-based alloy described in Patent Document 1 (Ni content: 2.5 mass%). Was made. Table 2 shows the component composition of the filler rod of Comparative Example 1.

(Comparative Example 2)
A commercially available filler rod (φ3.2 mm) of Stellite (Bicillite No. 21) was used as the filler rod of Comparative Example 2. Table 2 shows the component composition of the filler rod of Comparative Example 2.

<Verification test 1>
Welding workability at the time of welding using the filler rods of Examples 1-2 and Comparative Examples 1-2 was evaluated. Specifically, using the welding conditions shown in Table 3 below, the weldability when a weld specimen (test plate material: SCS6) as shown in FIG. 5 was produced was evaluated.

  In the filler rods of Example 1 and Comparative Example 1, there were 10 layers and 60 passes for one groove. In the filler rod of Example 2, there were 9 layers and 57 passes for one groove. Moreover, in the filler rod of the comparative example 2, it was 11 layers 60 passes with respect to one groove.

  In Examples 1 and 2 and Comparative Example 1 in which the diameter of the filler rod is φ2.0 mm, slag adheres to the weld bead but does not float as a lump in the molten pool during welding. It did not hinder the welding operation. Moreover, in Examples 1 and 2, it was easy to make the melted bead shape uniform even when the welding current was 200 A. On the other hand, in Comparative Example 1, the molten pool fluctuated with the same welding current, and it was somewhat difficult to make the bead shape uniform.

  On the other hand, in Comparative Example 2 in which the diameter of the filler rod is φ3.2 mm, it is considered that when the welding current is 200 A, the filler rod is difficult to melt, and there is a high risk of occurrence of poor fusion. , 250A or more) was confirmed to be necessary.

<Verification test 2>
The weld specimen prepared in Verification Test 1 was cut out and evaluated for tensile strength characteristics. The tensile strength characteristics were evaluated based on JIS Z2241 “Metal material tensile test method”. Table 4 shows the tensile test results (0.2% yield strength, tensile strength, elongation, drawing).

As shown in Table 4, it was found that the 0.2% proof stress and the tensile strength tend to increase as the Ni content decreases and decrease as the Ni content increases. By the way, “SCS5”, which is an example of a base material of a cast stainless steel product, is defined in JIS G 5121 as having a proof stress of 540 MPa or more and a tensile strength of 740 MPa. Since the tensile strength of the weld repair part should be larger than that of the base metal, the upper limit of the Ni content in the composition of the filler rod is 4. It was suggested that it was about 54% .

<Verification test 3>
The weld specimen prepared in the verification test 1 was cut out and evaluated for fracture toughness by the Charpy test. Fracture toughness was evaluated based on JIS Z2242 “Charpy impact test method for metal materials”.
The test piece had a V notch, a depth of 2 mm, a notch radius of 0.25 mm, and the test temperature was room temperature. In addition, the number of tests was set to two for each variation. Table 5 shows the Charpy impact test results (absorbed energy, Charpy impact value).

As shown in Table 5, it was found that the absorbed energy and the Charpy impact value tend to decrease as the Ni content decreases and increase as the Ni content increases. Incidentally, in a cast stainless steel product (for example, the base material “SCS5”), the design impact value is generally about 30 [J / cm ² ].
In Comparative Examples 1 and 2, it was confirmed that the Charpy impact value was much lower than 30 [J / cm ² ], which was lower than the base material of the stainless cast steel product.
On the other hand, in Examples 1 and 2, the Charpy impact value exceeded 30 [J / cm ² ], indicating that sufficient toughness was obtained.

<Verification test 4>
The weld specimen produced in the verification test 1 was cut out and the chemical composition of the weld metal part (weld alloy part) was examined. Table 6 shows the chemical composition of each weld metal part. The chemical components of the weld metal part were measured by the combustion-infrared absorption method for C and S, the absorptiometry for Si and P, and the ICP emission spectroscopic analysis for Mn, Ni, Cr, Mo, Co, and Fe.

   As shown in Table 6, in Examples 1 and 2 and Comparative Examples 1 and 2 in the weld metal part, Fe (iron) is affected by dilution from the base material (SCS6) side. The result was almost the same as the chemical composition of the filler rod shown in.

<Verification test 5>
The weld specimen prepared in the verification test 1 was cut out, and a cross-sectional structure at a weld metal part and a heat affected zone (hereinafter referred to as “HAZ part”) was observed.
As a result of observing the cross-sectional structure, the weld metal part (weld alloy part), which is a Co-based alloy, in all of Examples 1-2 and Comparative Examples 1-2, has a similar structure. Similarly, in the HAZ part, although there was a difference in the size of the defect on the base metal side, a significant difference could not be confirmed.

<Verification test 6>
The weld specimen prepared in verification test 1 was cut out and evaluated for cavitation erosion characteristics. In addition, as the cavitation erosion test, two types, a jet method using a cavitation jet test device according to ASTM G134-95 and a static test method using a magnetostriction vibration test device according to ASTM G32-06 are implemented. did.

In the jet method, a cabjet apparatus using a triple plunger pump was used. In order to keep the cavitation number at 0.025, the valves installed on the upstream side and the downstream side were adjusted. Here, the upstream pressure was 25 MPa, the downstream pressure was 0.6 MPa, and the test time was 24 h. The standoff distance between the jet jet nozzle and the test piece was 14 mm, and the test liquid was constant at 20 ° C. tap water. In addition, the number of tests was set to two for each variation.
In FIG. 6, the result of the volume reduction | decrease amount by Examples 1 and 2, Comparative Examples 1-2, and the SUS309 which is a conventional welding repair material by the jet method using a cavitation jet apparatus is shown.

In the stationary test method, a φ15.9 mm disc made of Ti alloy having excellent corrosion resistance was attached to the tip of the amplification horn of the vibrator, and the test piece was allowed to face in parallel with the disc with a gap of 1.0 mm. . This disc was replaced with a new one for each test. The resonance frequency of the vibrator was 19.5 kHz, and the total amplitude of the disk end face was constant at 50 μm. The test water was tap water, and was kept constant at 20 to 25 ° C., and the test time was 100 h. In general, the test time is set to 10 h or 24 h. However, since the initial damage rate is small and the cavitation number is considered to be small, the test time is set to 100 h that can give sufficient damage. In addition, the number of tests was set to two for each variation.
In FIG. 7, the result of the volume reduction | decrease amount by the stationary method using the magnetostriction vibration apparatus of Examples 1-2, Comparative Examples 1-2, and SUS309 which is a conventional welding repair material is shown.

  As a result of observing the cavitation erosion surface by a jet method using a cavitation jet device in two dimensions and three dimensions, the maximum depth of the SUS309 material used as a conventional welding repair material was 2.6 mm. On the other hand, in Examples 1-2 and Comparative Examples 1-2, which are Co-based alloys, the erosion depth is 1 mm, which is half or less than that of SUS309 material, and the erosion surface center is partially left. Met. Moreover, as shown in FIG. 6, the volume reduction amount of Examples 1-2 and Comparative Examples 1-2, which are Co-based alloys, is less dependent on the Ni content, and both are reduced by 65% with respect to the SUS309 material. It was confirmed that the cavitation erosion resistance was excellent.

  As a result of calculating the arithmetic average height Sa according to ISO 25178 for the cavitation erosion surface by the stationary method using the magnetostrictive vibration device, in Examples 1-2 and Comparative Examples 1-2, which are Co-based alloys, It was confirmed that the surface roughness was small. Further, as shown in FIG. 7, the volume reduction amounts of Examples 1 and 2 and Comparative Examples 1 and 2 which are Co-based alloys are less dependent on the Ni content, and both are reduced by 88% with respect to the SUS309 material. It was confirmed that the cavitation erosion resistance was excellent.

1 ... Filler material (Fused rod)
2 ... Cylindrical metal part 3 ... Alloy component adjustment part (alloy powder)
32 ... Strip steel made of Co plate (Co hoop material)

Claims (17)

% By mass
Ni: 2.7 to 4.5 4,
Mn: 1.5-10.0,
Fe: 3.0-30.0,
C: 0.03 to 0.60,
Si: 0.01 to 3.0,
Cr: 7-40,
A Co-based alloy for welding comprising Mo: 1.0 to 15.0, the balance being a component composition consisting of Co and inevitable impurities. % By mass
Ni: 3.5 to 4.5 4, welding Co-based alloy according to claim 1, characterized in that it comprises a. % By mass
W: 0.5 to 7.5, the welding Co-based alloy according to claim 1 or 2, characterized in containing Mukoto. % By mass
Ni: 2.7 to 4.5 4,
Mn: 1.5-10.0,
Fe: 3.0-30.0,
C: 0.03 to 0.60,
Si: 0.01 to 3.0,
Cr: 7-40,
A filler material characterized in that it is a Co-based alloy having a composition of Mo: 1.0 to 15.0, with the balance being Co and inevitable impurities. % By mass
Ni: 3.5-4.54 is included, The filler material of Claim 4 characterized by the above-mentioned. % By mass
W: 0.5 to 7.5, the filler material according to claim 4 or 5, characterized in including Mukoto. It is a filler material composed of a metal linear body that forms a weld alloy part by overlay welding,
The weld alloy part is mass%,
Ni: 2.7 to 4.5 4,
Mn: 1.5-10.0,
Fe: 3.0-30.0,
C: 0.03 to 0.60,
Si: 0.01 to 3.0,
Cr: 7-40,
A filler material characterized in that it is a Co-based alloy having a composition of Mo: 1.0 to 15.0, with the balance being Co and inevitable impurities. % By mass
Ni: 3.5-4.54 is included, The filler material of Claim 7 characterized by the above-mentioned. % By mass
W: 0.5 to 7.5, the filler material according to claim 7 or 8, characterized in containing Mukoto. The said metal linear body consists of the cylindrical metal part which forms an outer skin, and the alloy component adjustment part with which the inner side of the said cylindrical metal part was filled, The any one of Claim 7 thru | or 9 characterized by the above-mentioned. The filler metal as described in 2. The tubular metal part, Fe: contains 10 wt% or less, filler material according to claim 1 0 and the balance being a Co-based alloy having a component composition consisting of Co and inevitable impurities. Filler material according to claim 1 0 or 1 1 in which the thickness of the tubular metal part, characterized in that it is 0.25mm or less. The diameter of the metal wire-like body, filler material according to any one of claims 7 to 1 2 and less than 3.2 mm. The diameter of the metal wire-like body, filler material according to any one of claims 7 to 1 3, characterized in that it is 2.0mm or less. A built-up metal member including a weld alloy part formed by overlay welding a filler material,
The weld alloy part is mass%,
Ni: 2.7 to 4.5 4,
Mn: 1.5-10.0,
Fe: 3.0-30.0,
C: 0.03 to 0.60,
Si: 0.01 to 3.0,
Cr: 7-40,
A build-up metal member comprising a Co-based alloy having a composition of Mo: 1.0 to 15.0, with the balance being Co and inevitable impurities. % By mass
Ni: 3.5 to 4.5 4, the cladding metal member according to claim 1 5, characterized in that it comprises a. % By mass
W: 0.5 to 7.5, the cladding metal member according to claim 1 5 or 16, wherein the free Mukoto.

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