WO2019189531A1

WO2019189531A1 - Cr-Ni BASED ALLOY, RAPIDLY SOLIDIFIED MOLDED BODY MADE OF Cr-Ni BASED ALLOY, ALLOY POWDER, POWDER METALLURGY MOLDED BODY, CAST MOLDED BODY, PRODUCTION METHOD FOR Cr-Ni BASED ALLOY AND MECHANICAL EQUIPMENT USING Cr-Ni BASED ALLOY, AND PIPING MEMBER

Info

Publication number: WO2019189531A1
Application number: PCT/JP2019/013491
Authority: WO
Inventors: 長谷川　満; 西田　純一; 雅史能島; 上原　利弘; 友則木村; 青野　泰久
Original assignee: 日立金属株式会社
Priority date: 2018-03-28
Filing date: 2019-03-28
Publication date: 2019-10-03
Also published as: JP7380547B2; JPWO2019189531A1; JP2024020264A

Abstract

The present invention addresses the problem of providing a Cr-Ni based alloy which is a metal material that can be advantageously used in a harsh environment such as an oil well and has both high erosion resistance and high wear resistance that is equal to or better than conventional materials, and is also low-cost. A Cr-Ni based alloy according to the present invention comprises, by mass%: more than 40.0% and no more than 65.0% of Cr; 0-35.0% of Fe; 0% or more and less than 2.0% of Mn; any of (1) over 1.1% and no more than 4.0% of C, (2) 0.7-3.0% of B, and (3) 0.5-2.5% of C; and more than 0% and no more than 20% of Nb, wherein the remainder is made up of Ni and unavoidable impurities, and said Ni is 15% or more.

Description

Cr—Ni alloy, rapidly solidified molded body made of Cr—Ni alloy, alloy powder, powder metallurgy molded body, cast molded body, Cr—Ni alloy manufacturing method, and mechanical equipment using Cr—Ni alloy, Piping material

The present disclosure relates to a technology for a high corrosion resistance and high strength alloy, and in particular, a Cr—Ni alloy, a rapidly solidified molded body made of a Cr—Ni alloy, an alloy powder, a powder metallurgy molded body, a cast molded body, and a Cr—Ni system. The present invention relates to an alloy manufacturing method, mechanical equipment using a Cr—Ni alloy, and a piping member.

In equipment used for mining crude oil, natural gas, etc. and for transporting fluids, surface modification is performed by overlay welding a material with excellent corrosion resistance and wear resistance on the surface of a member that comes into contact with or slides into other materials. Means may be taken to provide a layer to reduce wear on the device components. Examples of such surface modifying materials include cobalt (Co) based alloys such as stellite (STELLITE is a registered trademark) and trivalloy (TRIBALOY is a registered trademark), and nickel (Ni) based such as colmonoy (COLMONOY is a registered trademark). Alloys are commercially available and widely used. However, these main raw materials, Co and Ni, are expensive and there is a problem that the material cost increases.

For this purpose, various Cr-based alloys mainly composed of relatively inexpensive chromium (Cr) have been proposed. For example, in Japanese Patent Laid-Open No. 10-110206, Cr: 82 to 90 mass%, C: 2 Disclosed is a method for producing a Cr—Ni alloy having a chemical composition containing Ni and subcomponents of up to 6% by mass and the balance of 7.9% by mass or more, and is used for forming a coating having corrosion resistance and wear resistance. It is supposed to be possible. Japanese Patent Laid-Open No. 11-285890 discloses a welding rod in which an alloy powder containing a high concentration of Cr and C is encapsulated with a sheath material made of a Cr—Ni containing alloy, and a welding rod having a desired composition is disclosed. It is said that the rod can be manufactured efficiently. Further, in JP-A-11-293377, Cr: 50 to 80% by mass, at least one of Ti, Mn, Mo and Zr: 2 to 10% by mass, and the hearth member of the heating furnace containing Ni and subcomponents in the balance Cr-based alloys are disclosed, and it is said that an alloy excellent in creep resistance and oxidation resistance can be provided with high productivity.

JP-A-10-110206 Japanese Patent Laid-Open No. 11-285890 JP-A-11-293377 International Publication No. 2017/037851 Pamphlet International Publication No. 2009/064415 Pamphlet JP 2005-314721 A

An alloy produced by the method described in JP-A-10-110206 has an extremely high Cr content, and the melting point of the alloy is considered to be a high temperature exceeding 1500 ° C. This leads to an increase in energy required for the production of the alloy and requires a high production cost. Further, the welding rod described in Japanese Patent Laid-Open No. 11-285890 needs to enclose the alloy powder in the sheath material, and requires a higher manufacturing cost than the case where the alloy itself is made into a wire or powder. Become. Further, it is stated that in the Cr-based alloy described in JP-A-11-293377, it is desirable to add 2% by mass or more of Ti, Mn, etc. in order to improve the compressive strength and creep resistance. However, in the Cr-based alloy described in the pamphlet of International Publication No. 2017/037851 examined by the inventors, for example, when Mn exceeds 2% by mass, coarse particles of sulfide (for example, MnS) are formed, and corrosion resistance and It is thought that it becomes a deterioration factor of mechanical characteristics.
In addition, for example, in the field of oil well drilling, in recent years, the environment in which equipment is exposed as the depth increases has become harsh, and high-corrosion resistance, mechanical properties, and low-cost metal materials are strongly used. It has been demanded.

One aspect of the present disclosure is a metal material that can be suitably used even in a harsh environment such as an oil well. The metal material has high corrosion resistance and wear resistance equal to or higher than those of conventional ones, and is low in cost. It is an object to provide an alloy.
Another aspect of the present disclosure uses a rapidly solidified formed body, an alloy powder, a powder metallurgy formed body, a cast formed body, a method for producing a Cr—Ni based alloy, and a Cr—Ni based alloy using the Cr—Ni based alloy. It is an object to provide mechanical equipment and piping members.

Specific means for solving the above problems include the following modes.
<1> By mass%
More than 40.0% and 65.0% or less of Cr,
0% or more and 35.0% or less of Fe;
Mn from 0% to less than 2.0%,
Including any of the following (1) to (3),
(1) C over 1.1% and 4.0% or less
(2) 0.7% to 3.0% B
(3) C of 0.5% or more and 2.5% or less and Nb of more than 0% and 20% or less
A Cr—Ni alloy in which the balance is made of Ni and inevitable impurities, and the Ni is 15% or more.

<2> By mass%
46.0% to 65.0% Cr,
0.1% or more and 30.0% or less of Fe;
More than 0% and less than 2.0% Mn,
1.1% to 4.0% or less of C,
The Cr—Ni alloy according to <1>, wherein the balance is made of Ni and inevitable impurities.
<3> By mass%
45.0% or more and 65.0% or less of Cr;
0.1% or more and 35.0% or less of Fe;
More than 0% and less than 2.0% Mn,
0.7% or more and 3.0% or less of B,
The Cr—Ni alloy according to <1>, wherein the balance is made of Ni and inevitable impurities.
<4> Over 40.0% and 65.0% or less of Cr,
Fe of 0% or more and 30.0% or less;
0.5% or more and 2.5% or less of C and more than 0% and 20% or less of Nb,
The Cr—Ni alloy according to <1>, wherein the balance is made of Ni and inevitable impurities.
<5> By mass%
0.1% or more and 1.0% or less of Si,
0.005% or more and 0.05% or less of Al,
0.02% to 0.3% Sn,
0.1% or more and 5.0% or less of Cu,
The Cr—Ni-based alloy according to any one of <1> to <4>, including at least one of the above.
<6> The Cr—Ni alloy according to any one of <1> to <5>, wherein the Cr—Ni alloy has a ferrite phase and / or an austenite phase.

<7> A rapidly solidified molded body comprising the Cr—Ni alloy according to any one of <1> to <6>.
<8> An alloy powder comprising the Cr—Ni alloy according to any one of <1> to <6>.
<9> A powder metallurgy formed of the Cr—Ni alloy according to any one of <1> to <6>.
<10> A cast molded body made of the Cr—Ni alloy according to any one of <1> to <6>.

<11> A method for producing a Cr—Ni alloy according to any one of <1> to <6>,
A melting step of melting a raw material of the Cr-Ni alloy to form a molten metal;
And an atomizing step for producing an alloy powder from the molten metal.
<12> A method for producing a Cr—Ni alloy according to any one of <1> to <6>,
A melting step of melting a raw material of the Cr-Ni alloy to form a molten metal;
A casting step of casting the molten metal to form a cast molded body;
A pulverization step of mechanically pulverizing the cast compact to produce an alloy powder.

<13> A method for producing a Cr—Ni alloy according to any one of <1> to <6>,
A powder forming step of forming a powder compact by performing press molding or injection molding using the powder made of the Cr—Ni alloy as a raw material, and firing the powder compact at a temperature lower than the solidus temperature of the alloy. And a sintering step of forming a powder metallurgy molded body by performing a heat treatment.
<14> A method for producing a Cr—Ni alloy according to any one of <1> to <6>,
A melting step of melting a raw material of the Cr-Ni alloy to form a molten metal;
And a casting step of casting the molten metal to form a cast molded body.

<15> Mechanical equipment for transporting or processing a transported object containing solid matter and / or corrosive components, the member itself constituting the mechanical equipment and contacting the transported object or the transported object of the member Equipment in which at least part of the surface in contact with the surface is made of the Cr—Ni alloy according to any one of <1> to <6>.
<16> A piping member used for a transport path of a transported object containing solid matter and / or a corrosive component, wherein at least a part of the surface of the piping member itself or the surface of the piping member that contacts the transported object is < A piping member made of the Cr—Ni alloy according to any one of 1> to <6>.

According to one aspect of the present disclosure, for example, a metal material having corrosion resistance and wear resistance that can withstand severe corrosive environments such as direct contact with various quality fuels and deteriorated lubricants, and a Ni-based alloy or A Cr—Ni alloy is provided as a material that can be manufactured at a lower cost than a Co-based alloy.
According to another aspect of the present disclosure, a rapidly solidified formed body, an alloy powder, a powder metallurgy formed body, a cast formed body, or a Cr—Ni based alloy of the Cr—Ni based alloy according to an aspect of the present disclosure was used. Mechanical equipment and piping members can have both high corrosion resistance and wear resistance equal to or higher than those of conventional materials.

FIG. 6 is an example of a method for producing a Cr—Ni alloy according to the present disclosure, and is a process diagram illustrating a method for producing an alloy powder and a rapidly solidified molded body. FIG. 5 is a process diagram illustrating a method for producing a powder metallurgy molded body, which is another example of the method for producing a Cr—Ni based alloy according to the present disclosure. FIG. 5 is a process diagram showing a method for producing a cast body, which is another example of the method for producing a Cr—Ni alloy product according to the present disclosure. It is a figure which shows the cross-sectional schematic diagram of the screw pump which is an application example of the Cr-Ni type alloy which concerns on this indication, an injection mold, and a crusher. FIG. 3 is a graph showing the relationship between the corrosion rate obtained by the boiling sulfuric acid test and the wear volume obtained by the earth and sand wear test in the Cr—Ni based alloy according to Example 1. 6 is a diagram showing an image observed by an electron microscope of a cross-section polished surface of a cast molded body of a Cr—Ni-based alloy of Comparative Example (Nos. 1 and 2) of Example 1. FIG. 6 is a view showing an image observed by an electron microscope of a cross-section polished surface of a cast molded body in a Cr—Ni-based alloy of Comparative Example (Nos. 3 and 4) of Example 1. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-section polished surface of a cast molded body of a Cr—Ni-based alloy of Example 1 (Nos. 5 and 6) of Example 1. FIG. FIG. 3 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni based alloy of Example 1 (Nos. 7 and 8) of Example 1. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni based alloy of Example 1 of the present invention (No. 9, 10, 11) in Example 1. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni based alloy of Example 1 of the present invention (No. 12, 13, 14) in Example 1. FIG. FIG. 6 is a graph showing the relationship between the corrosion rate obtained by the boiling sulfuric acid test and the wear volume obtained by the earth and sand wear test in the Cr—Ni based alloy according to Example 2. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni—Fe based alloy of Example 2 of the present invention (No. 21, 22) of Example 2. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni—Fe based alloy of Example 2 of the present invention (No. 23, 24) in Example 2. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni—Fe-based alloy of Example 2 of the present invention (No. 25, 26) in Example 2. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-section polished surface of a cast molded body of a Cr—Ni—Fe-based alloy of Comparative Example (No. 27) of Example 2. FIG. FIG. 6 is a view showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni—Fe-based alloy of Example 2 of the present invention (No. 28). FIG. 6 is a graph showing the relationship between the corrosion rate obtained by the boiling sulfuric acid test and the wear volume obtained by the earth and sand wear test in the Cr—Ni based alloy according to Example 3. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast molded body of a Cr—Ni based alloy of Example 3 of the present invention (No. 31, 32, 33) in Example 3. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast body of a Cr—Ni alloy of Example 3 of the present invention (No. 34, 35) in Example 3. FIG. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-section polished surface of a cast body of a Cr—Ni-based alloy of Example 3 of the present invention (No. 36, 37) in Example 3. 6 is a view showing an image observed by an electron microscope of a cross-section polished surface of a cast body of a Cr—Ni based alloy of Example 3 of the present invention (No. 38, 39) in Example 3. FIG. 6 is a diagram showing an image observed by an electron microscope of a cross-sectional polished surface of a cast body of a Cr—Ni based alloy of Example 3 of the present invention (No. 40, 41) in Example 3. FIG. FIG. 4 is a diagram showing a relationship between a corrosion rate obtained by a boiling sulfuric acid test and a wear volume obtained by an earth and sand abrasion test in an overlay material which is a comparison object with the Cr—Ni—Fe alloy according to the present disclosure. .

In this specification, a numerical range expressed using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. In a numerical range described stepwise in the present disclosure, an upper limit value or a lower limit value described in one numerical range may be replaced with an upper limit value or a lower limit value of another numerical range described. Further, in the numerical ranges described in the present disclosure, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.
In this specification, the term “process” is not limited to an independent process, and is included in this term if the intended purpose of the process is achieved even when it cannot be clearly distinguished from other processes. .

The inventors of the present invention have investigated and investigated the relationship among the chemical composition, the metallographic morphology, the corrosion resistance, and the earth and sand wear resistance in the Cr—Ni alloy, and completed the present invention.
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. However, the same reference numerals are assigned to synonymous states / processes, and duplicate descriptions are omitted. Further, the present invention is not limited to the embodiments described here, and can be appropriately combined with or improved based on known techniques without departing from the technical idea of the invention. It is.

[Chemical composition]
The disclosed Cr—Ni-based alloy is in mass%.
More than 40.0% and 65.0% or less of Cr,
0% or more and 35.0% or less of Fe;
Mn from 0% to less than 2.0%,
Including any of the following (1) to (3),
(1) C over 1.1% and 4.0% or less
(2) 0.7% to 3.0% B
(3) C of 0.5% or more and 2.5% or less and Nb of more than 0% and 20% or less
The balance is made of Ni and inevitable impurities, and the Ni is 15% or more of a Cr—Ni alloy.
The Cr—Ni-based alloy of the present disclosure suppresses the Cr amount and forms at least one compound of Cr-based carbide, Cr-based boride, and Nb-based carbide in the matrix phase, so that it can be used in a harsh environment such as an oil well. Is a low-cost Cr—Ni-based alloy having both high corrosion resistance and wear resistance that can be suitably used.

Hereinafter, the composition (each component) of the Cr—Ni alloy according to the present disclosure will be described. Unless otherwise specified, the content of each element is mass%. Note that the total content of the disclosed components in the Cr—Ni-based alloy according to the present disclosure is preferably more than 99% by mass. The total content is preferably less than 1% by mass.

Cr: more than 40.0% and not more than 65.0% Cr is one of the main components of the Cr—Ni-based alloy of the present disclosure, and is an important component for obtaining good corrosion resistance. It is preferable that the Cr content is more than 40.0%, and the Cr content is the maximum content from the viewpoint of corrosion resistance and material cost. This is because the alloy of the present disclosure uses Cr, which is cheaper than Ni, as the maximum component, and thus has an advantage that the material cost can be reduced as compared with, for example, a Ni-based alloy containing expensive Ni as the maximum component. Further, by using Cr as the maximum component, an oxide film is easily formed and a passive state is formed, so that the corrosion resistance is improved. When the Cr content is 40.0% or less, the amount of carbides appearing in the alloy structure decreases, and the wear resistance may be insufficient. Alternatively, Cr in the alloy structure may decrease and corrosion resistance may deteriorate. On the other hand, if the Cr content exceeds 65.0%, the melting point of the alloy becomes high, the energy required for ingot production by melting and pulverization by atomization increases, the productivity deteriorates, and the production cost increases. The Cr content is 65.0% or less.

Also, Cr is a component that contributes to the formation of carbides related to the improvement of wear resistance together with C described later. That is, when the above-mentioned “(1) C of 1.1% to 4.0% or less” is included, Cr forms Cr-based carbide together with C. In this embodiment, the Cr content is preferably more than 46.0%, more preferably 50.0% or more, and more preferably 55.0% or more in order to exert the effect of Cr more reliably. Is more preferable.

Further, Cr is a component that contributes to the formation of borides related to the improvement of wear resistance together with B described later. That is, when the above-mentioned “(2) B of 0.7% or more and 3.0% or less” is included, Cr forms a Cr boride together with B. In this embodiment, in order to exhibit the effect of Cr more reliably, Cr is preferably 45.0% or more, more preferably 50.0% or more, and further preferably 55.0% or more.

Further, Cr, together with C, is a component that contributes to the formation of carbides related to the improvement of wear resistance. However, “(3) C of 0.5% to 2.5% and above 0% When it contains 20% or less Nb ", Cr constitutes a Cr-based carbide together with C. In order to exhibit the effect of Cr more reliably, the Cr content is more than 40.0%, and more preferably 43.0% or more. More preferably, it is 50.0% or more, and more preferably 55.0% or more.

Fe: 0% or more and 35.0% or less Fe contributes to the formation of carbide together with Cr and the like. When Fe dissolves in the carbide, the amount of Cr solid solution in the carbide decreases, and a decrease in the Cr concentration in the matrix around the carbide is suppressed. Moreover, since the decrease in Cr concentration in the matrix phase causes a decrease in corrosion resistance, the addition of Fe improves the corrosion resistance. On the other hand, if there is too much Fe, ferrite crystallizes out as primary crystals, and the corrosion potential difference in the matrix phase increases, so that local corrosion tends to occur. Therefore, the content of Fe contained in the alloy of the present disclosure is set to 35.0% or less.

Moreover, when Fe includes the above-mentioned “(1) C of 1.1% to 4.0% or less”, it is preferably 0.1% or more and 30.0% or less. Here, as described above, Fe contributes to the formation of carbide together with Cr and the like. When Fe dissolves in the carbide, the amount of Cr solid solution in the carbide decreases, and a decrease in the Cr concentration in the matrix around the carbide is suppressed. Moreover, since the decrease in Cr concentration in the matrix phase causes a decrease in corrosion resistance, the addition of Fe improves the corrosion resistance. On the other hand, if there is too much Fe, ferrite crystallizes out as primary crystals, and the corrosion potential difference in the matrix phase increases, so that local corrosion tends to occur. Therefore, in the case of the above-described form, the Fe content is preferably 30.0% or less. It is more preferable to keep the content low within a range of 0.1% or more as long as the performance of the material is not impaired. Considering the wear resistance, the upper limit of the Fe content is preferably 15% or less, more preferably 8% or less.

In addition, when Fe includes the above-mentioned “(2) B of 0.7% or more and 3.0% or less”, it becomes an essential component for securing good mechanical properties, and 0.1% or more and 35.35. It is preferably 0% or less. When the Fe content is excessive, a σ phase of a brittle intermetallic compound is likely to be generated in the temperature range near 800 ° C., and the ductility and toughness of the Cr—Ni-based alloy are significantly reduced (so-called σ phase embrittlement). Therefore, it is more preferable that the Fe content is 35.0% or less, and the content is kept low within a range of 0.1% or more as long as the performance of the material is not impaired. Considering the corrosion resistance, the Fe content is preferably 20% or less, more preferably 15% or less.

Further, when Fe includes “(3) 0.5% or more and 2.5% or less of C and Nb of more than 0% and 20% or less” as described above, Fe is an element that improves the corrosion resistance. As a result, the ferrite phase crystallizes out, forms two phases with the austenite phase, and can form a hard, tough, high-strength matrix. On the other hand, when the amount of Fe added is increased, a sigma phase which is an embrittlement phase is generated, and mechanical properties may be impaired. Therefore, in this embodiment, the Fe content is preferably 30.0% or less. In addition, the addition of a large amount of Fe tends to increase the strength, but on the other hand, the amount of Cr decreases, which causes deterioration in corrosion resistance or wear resistance. In order to obtain certain characteristics of wear resistance and corrosion resistance, the range is preferably 20% or less. More preferably, it is 16% or less. Moreover, when this alloy is used as a build-up material for an inexpensive steel material, Fe may be 0% because Fe is mixed from the steel material used as a base material.

Mn: 0% or more and less than 2.0% Mn is a component that plays a role of desulfurization / deoxygenation particularly in the process of mixing and dissolving raw materials and contributes to improvement of mechanical properties and carbon dioxide corrosion resistance. . However, in the case of adding a deoxidizing element in place of Mn, Mn may not be added (0%). When Mn is contained, the Mn content is less than 2.0%. When the Mn content is 2.0% or more, coarse particles of sulfide (for example, MnS) are formed, which causes a decrease in corrosion resistance and mechanical properties. In order to exhibit the effect of Mn more reliably, the lower limit of Mn is preferably set to 0.05%.
In addition, Mn has the above-mentioned form including “(1) 1.1% to 4.0% or less C” and “(2) 0.7% to 3.0% B”. In that case, it is preferably more than 0%.

In the embodiment including “(1) C greater than 1.1% and not greater than 4.0%”, C is greater than 1.1% and not greater than 4.0%.
C has an effect of hardening the alloy by crystallization or precipitation as a carbide or solid solution in a matrix other than the carbide. In the case of this form, in order to obtain the effect of improving the wear resistance, it is preferable to form a massive Cr-based carbide containing Cr as a main component in the matrix phase with the C content exceeding 1.1%. As the C content increases, hard carbide particles tend to increase and wear resistance tends to improve, but Cr in the matrix phase is consumed and becomes a factor that deteriorates corrosion resistance. In consideration of the balance between wear resistance and corrosion resistance, C is set to 4.0% or less. In order to exhibit the above-described effects of C more reliably, it is preferable to set the lower limit of C to 1.5% and the upper limit to 3.5%. The massive Cr-based carbide means, for example, a carbide having a size such that a circle of 5 μm or more can be drawn in the carbide as seen in FIG. In FIG. 8, the portion displayed in dark gray or black is carbide. The composition of the carbide can be confirmed, for example, by quantitative analysis with an energy dispersive X-ray analyzer. The Cr-based carbide means a material containing the largest amount of Cr in the quantitative analysis result.

In the above-described embodiment including “(2) B of 0.7% or more and 3.0% or less”, B is 0.7% or more and 3.0% or less.
B (boron) has the effect of crystallizing or precipitating a hard boride effective for wear resistance in the matrix. In order to obtain an effect of improving the wear resistance, it is preferable that the B content is 0.7% or more and a massive Cr boride containing Cr as a main component is formed in the matrix. As the B content increases, the proportion of hard borides in the structure tends to increase and wear resistance tends to improve. To make the effects of B more effective, B is 1.0% or more. More preferably, it is preferably 1.5% or more. On the other hand, if the B content is excessively large, Cr in the parent phase is consumed with the formation of borides, which causes deterioration in corrosion resistance. In addition, crystallization of coarse borides serves as a starting point for cracking during the build-up operation. Furthermore, since corrosion caused by borides occurs, the corrosion resistance also decreases. Therefore, considering the balance between wear resistance and corrosion resistance, B is preferably 3.0% or less, more preferably 2.5% or less, and even more preferably 2.0% or less. Note that the massive Cr-based boride has, for example, a black elongated shape as shown in FIG. 13 and an elongated cross-sectional shape of 3 μm or more in the width direction and 30 μm or more in the longitudinal direction. The composition of the boride can be confirmed by, for example, quantitative analysis with an energy dispersive X-ray analyzer (EDX). The Cr-based boride is one in which B is detected in the quantitative analysis result by EDX and the largest amount of Cr is included in the metal elements excluding B.

In the form including the above-mentioned “(3) C of 0.5% or more and 2.5% or less and Nb of more than 0% and 20% or less”, C is 0.5% or more and 2.5% or less, Nb is , More than 0% and 20% or less.
Here, C has the effect of hardening the alloy by crystallizing or precipitating as a carbide in the Cr—Ni-based alloy of the present disclosure or by dissolving in a matrix other than the carbide. In order to obtain an effect of improving the wear resistance, it is preferable to form a massive Nb-based carbide containing Nb as a main component with a C content of 0.5% or more. In addition, as the C content increases, hard Nb carbide particles tend to increase and wear resistance tends to improve. However, if the C content increases beyond the above-mentioned ratio, Cr in the parent phase (base) is consumed. As a result, the hardness increases, but it becomes a factor that deteriorates the corrosion resistance. In consideration of the balance between wear resistance and corrosion resistance, C is set to 2.5% or less. In order to exhibit the above-described effects of C more reliably, the lower limit of C is preferably 0.8%, and the upper limit is preferably 1.5%.
In addition, Nb has the effect of generating an austenite phase by crystallizing or precipitating as Nb-based carbide in the Cr—Ni-based alloy of the present disclosure or by forming a solid solution in a parent phase other than carbide. . In order to obtain an effect of improving wear resistance, it is preferable to form a massive Nb-based carbide containing Nb as a main component by setting the Nb content to more than 0%. In addition, when the Nb content increases, hard Nb-based carbide particles tend to increase and wear resistance tends to improve. However, when the Nb content increases, it binds to Ni that forms an austenite phase and improves toughness. , Nb is more expensive than Ni and may deteriorate cost performance. Further, increasing Nb decreases Cr, Ni, and Fe forming the parent phase, and thus increases hardness and wear resistance, but causes deterioration in mechanical properties and corrosion resistance. In consideration of the balance between wear resistance, corrosion resistance, and mechanical properties, Nb is set to 20% or less, but a preferable upper limit of Nb is 16%. In order to exhibit wear resistance, the lower limit is preferably 4%. Moreover, in order to exhibit the effect of the above-mentioned Nb carbide more reliably, the lower limit of Nb is more preferably 6.4%, and the upper limit is preferably 12%. Moreover, it is desirable to add so that the ratio of Nb and C is% by mass and Nb: C is approximately 8: 1. The Nb-based carbide refers to, for example, a polygonal massive carbide as shown in FIGS. 19 and 20 and an amorphous shape that looks like feathers, dendrites, and lines. The composition of the carbide can be confirmed, for example, by quantitative analysis with an energy dispersive X-ray analyzer. The Nb-based carbide means a substance in which C is detected in the result of the quantitative analysis and Nb is contained most in the metal elements excluding C.

The balance is Ni and inevitable impurities:
In addition to the elements described above, Ni and unavoidable impurities. Among these, Ni is one of the main elements of the coating layer, and many of them are dissolved in the matrix other than the carbide and hardly dissolved in the carbide. When Ni dissolves in the matrix phase, the austenite phase constituting the matrix phase is stabilized, and the formation of ferrite in the primary crystal is suppressed and the corrosion resistance is improved. In order to fully exhibit this effect, the range in which the Ni content exceeds the aforementioned Fe content is preferable. Further, the Ni content is preferably 15% or more, more preferably 25% or more, and still more preferably 30% or more. On the other hand, if the amount of Ni is excessively large, the above-described effect of Cr may be impaired. Therefore, the upper limit of the Ni content is preferably less than the Cr content.
In addition to the above-mentioned Ni, the balance includes impurities inevitably contained in production. Among these impurities, the impurities to be particularly restricted are as follows.
Impurities P and S are easily segregated at the grain boundaries and cause corrosion resistance. Therefore, P is limited to 0.02% or less, and S is limited to less than 0.005%. S is preferably 0.003% or less, and more preferably 0.002% or less. In addition, O, N, etc. should be kept as low as possible because they combine with Cr to form oxide-based and nitride-based inclusions to reduce cleanliness and deteriorate corrosion resistance and fatigue strength. Is preferred. For this reason, preferable O is 0.002% or less, and N is 0.04% or less. In addition, a small amount of Ta may be mixed as an impurity in Nb. However, if Ta is in the range of 0.2% or less, the influence is small, and it is not necessary to limit it to a particularly low level.

Si: 0.1% or more and 1.0% or less Si is one of the optional components of the disclosed Cr—Ni alloy, and plays a role of deoxidation and contributes to improvement of mechanical properties. . When Si is contained, the Si content is preferably 0.1% or more and 1.0% or less. When the Si content is less than 0.1%, the effect based on Si tends to be insufficient. On the other hand, when Si exceeds 1%, coarse particles of oxide (for example, SiO2) are formed, which causes a decrease in mechanical properties.
Al: 0.005% or more and 0.05% or less Al is also an optional component of the Cr—Ni alloy of the present disclosure, and is a component that contributes to an improvement in the deoxidation effect by combining with Mn and Si. . When Al is contained, the Al content is preferably 0.005% or more and 0.05% or less. If the Al content is less than 0.005%, the effect of Al may not be sufficiently obtained. On the other hand, when the Al content exceeds 0.05%, coarse particles of oxides and nitrides (for example, Al2O3 and AlN) are formed, resulting in a decrease in mechanical properties.

Sn: 0.02% or more and 0.3% or less Sn is an optional component that plays a role of strengthening a passive film in the disclosed Cr—Ni-based alloy and contributes to improvement of corrosion resistance and wear resistance. Specifically, improvement in resistance to chloride ions and acidic corrosive environments can be expected. In the case of containing Sn, the Sn content is preferably 0.02% or more and 0.3% or less. If the Sn content is less than 0.02%, the effect based on Sn cannot be sufficiently obtained. On the other hand, if the Sn content exceeds 0.3%, grain boundary segregation of the Sn component occurs, which causes a decrease in ductility and toughness of the alloy.
Cu: 0.1% or more and 5.0% or less Cu is an optional component that contributes to the improvement of corrosion resistance in the Cr—Ni alloy of the present disclosure. When Cu is contained, the content is preferably 0.1% or more and 5.0% or less. When the Cu content is less than 0.1%, the effect based on Cu cannot be sufficiently obtained. On the other hand, if the Cu content exceeds 5.0%, Cu precipitates are likely to be generated, which causes a decrease in ductility and toughness of the alloy.

As described above, the alloy of the present disclosure to be described is preferably formed into an alloy powder and used for forming a surface modified layer by overlay welding. The melted alloy of the present disclosure may be pulverized by gas atomization that is introduced into a high-speed gas stream of an inert gas and pulverized, and may be applied by a PTA (Plasma transfer arc) overlay welding apparatus. In a PTA build-up welding apparatus, since the powder is normally conveyed by flowing the pipe line to the construction part at the tip of the welding torch, the powder needs to move smoothly. On the other hand, the powder obtained by gas atomization is preferable because it is spherical and has good fluidity. In addition, a powdered alloy of the present disclosure that has been sintered into a rod-shaped powder metallurgy formed by powder metallurgy may be used as a welding rod.

<Method for producing Cr-Ni alloy>
Next, a method for producing the Cr—Ni alloy of the present disclosure will be described.
FIG. 1 is an example of a method for producing a Cr—Ni alloy product according to the present disclosure, and shows a method for producing an alloy powder (here, powder and overlay welding material) made of a rapidly solidified cast body. FIG. As shown in FIG. 1, first, a melting step (step 1: S1) is performed in which the raw material of Cr—Ni alloy is melted to form a molten metal 10 to have a desired composition. There is no particular limitation on the method of melting the raw material, and a conventional method in the production of a high corrosion resistance and high strength alloy can be used. The molten metal 10 may be refined by a predetermined method to form a highly purified molten metal 12 with a reduced content of impurity components (FIG. 3).

Next, by performing an atomizing step (step 2: S2) using the molten metal 10 or the purified molten metal 12 as a starting material, the alloy powder 20 of the Cr—Ni alloy can be obtained. As a kind of atomization method, for example, there is a method of obtaining a powder by pulverizing a molten metal by spraying a high-pressure medium against the flow of the molten metal, and it is classified into gas atomization and water atomization depending on the kind of medium used. In the present disclosure, there is no particular limitation on the atomizing method, but it is preferable to use a gas atomizing method that can obtain a more clean and homogeneous composition / spherical particle for use in building powder. The obtained alloy powder 20 can be suitably used as, for example, a welding material, a powder metallurgy material, and a layered modeling material. The target composition is preferably a two-phase alloy containing a carbide and a parent phase consisting of a ferrite phase and an austenite phase, or an alloy that is a single-phase alloy of an austenite phase. In the case of a two-phase alloy, it is preferable that the austenite phase exhibits a volume ratio of 20% or more.
Next, you may implement the classification process (step 3: S3) for aligning with a desired particle size with respect to the alloy powder 20 obtained by performing atomization process S2. Classification step S3 is not an essential step, but when alloy powder 20 is used as a material for overlaying, classification is performed from the viewpoint of stable powder supply to the welding equipment and stabilization of the overlaying process. It is preferable to do. Although there is no particular limitation on the particle size to be classified, for example, a particle size range of 63 μm or more and 250 μm or less may be extracted and used for PTA overlay welding. When used for a powder metallurgy molded body to be described later, it may be classified and selected in a particle size range of, for example, 1 μm to 50 μm from the viewpoint of dimensional accuracy of the molded body and prevention of residual voids.

Next, when the build-up welding process (step 4: S4) is performed on the desired base material 41 using the alloy powder 20, the molten alloy powder 20 is rapidly cooled by the temperature difference with the base material 41 and the outside air. Thus, it is possible to obtain the overlay welding material 40 on which the alloy coating layer 42 which is a rapidly solidified compact exhibiting a rapidly solidified structure is formed. In the case of the form including “(2) 0.7% or more and 3.0% or less B” of the present disclosure, the rapidly solidified structure is a massive Cr having a size capable of drawing a circle having a diameter of 3 μm or more inside thereof. A metal structure having a boride is preferable.
In the present disclosure, the build-up welding step S4 includes thermal spraying using metal powder.
Although the obtained overlay welding material 40 may be used as a member constituting various devices as it is, a shaping process for shaping the dimension and shape of the overlay welding material 40 in consideration of connection to other members (step 5). : S5) may be further performed. Examples of the shaping means include cutting with a milling machine and polishing with a grindstone.

In addition, as a rapidly solidified molded body having a rapidly solidified structure, for example, a molten Cr—Ni-based alloy may be sprayed onto a roll rotating at a high speed to be rapidly cooled into a thin strip-shaped cast molded body. Alternatively, the alloy powder may be laminated while spraying the alloy powder, and a laminate shaped body (rapidly solidified formed body) having a rapidly solidified structure may be obtained.
Further, as a method for obtaining an alloy powder different from the above, an alloy powder is manufactured by applying a powdering step of mechanically pulverizing the cast molded body obtained by the casting step to obtain an alloy powder. Also good. In this case, as the powdering step, for example, a ball mill or the like can be applied.

FIG. 2 is an example of a method for producing a Cr—Ni alloy according to the present disclosure, and is a process diagram illustrating a method for producing a powder metallurgical compact. As shown in FIG. 2, the manufacturing process of the powder metallurgy molded body is the same as the manufacturing method of the rapidly solidified molded body of FIG. 1 up to the atomizing process S2 or the classification process S3, and powder molding instead of the overlay welding process S4. The difference is that the process (step 6: S6) and the sintering process (step 7: S7) are performed. Therefore, the powder forming step S6 and the sintering step S7 will be described.
The desired powder compact 60 can be obtained by performing the powder molding step S6 using the alloy powder 20 obtained by performing the atomizing step S2 or further through the classification step S3. Although there is no particular limitation on the powder molding method, for example, in the case of metal powder injection molding method, the alloy powder 20 is kneaded with plastic or wax as a binder to give fluidity and moldability, and then molded with an injection molding machine. A powder forming element process (step 6a: S6a) that fills and molds and a degreasing element process (step 6b: S6b) that removes the binder remaining in the obtained powder molded body 60 can be performed. In the degreasing step, for example, the powder compact is immersed in a solvent or heated in a predetermined atmosphere.

Next, a sintering step S7 is performed on the powder compact 60 by performing a sintering heat treatment below the solidus temperature of the alloy to form the powder metallurgical compact 70. There is no particular limitation on the sintering heat treatment method, and a conventional method can be used. In addition, when performing the above-mentioned degreasing process S6b by heating, the degreasing process and the sintering process are adjusted by adjusting the temperature and atmosphere at the time before reaching the sintering temperature in the sintering process S7. It can also be done in a batch. From the viewpoint of densification of the powder metallurgy molded body 70, it is more preferable to include a hot isostatic pressing (HIP) treatment at a temperature lower than the solidus temperature of the alloy and 500 to 3000 atm.
The obtained powder metallurgy molded body 70 has a sintered structure and may be used as it is as a member constituting various devices. If the powder metallurgical compact 70 is rod-shaped, this can be applied as an electrode rod of an arc welding machine, for example, and can be used for overlay welding on a desired substrate.
Further, as in the case of the above-described overlay welding material, a shaping step S5 for shaping the size and shape of the powder metallurgy shaped body 70 in consideration of connection to other members may be further performed to obtain the shaped body 50. . Examples of the shaping means include cutting with a milling machine and polishing with a grindstone.

FIG. 3 is an example of a method for producing a Cr—Ni alloy according to the present disclosure and is a process diagram illustrating a method for producing a cast product. As shown in FIG. 3, the manufacturing process of the cast molded body is different in that the melting step S1 is the same as the manufacturing method of the rapidly solidified molded body of FIG. 1, and the casting process (step 8: S8) is performed thereafter. The molten metal 10 obtained by performing the melting step S1, or the cleaned molten metal 12 obtained through the electrode manufacturing step S1a and the remelting step S1b is filled in a desired casting mold in the casting step S8, and then cooled, The cast molded body 80 can be obtained by curing. There is no particular limitation on the casting method.
In order to further reduce the content of impurity components (O, P and S) in the alloy (in order to increase the cleanliness of the alloy), the melting step S1 mixes and melts the raw material of the Cr—Ni based alloy to melt the molten metal. The electrode manufacturing process (Step 1a: S1a) in which the consumable electrode 11 is manufactured by solidifying by casting after forming the electrode 10 and the remelting process (Step 1b: S1b) in which the consumable electrode is remelted to prepare the cleaned molten metal 12. ) May be applied. The remelting method is not particularly limited as long as the cleanliness of the alloy can be increased. For example, vacuum arc remelting (VAR) or electroslag remelting (ESR) can be preferably used. When the remelting step is applied, the ingot obtained by remelting becomes a cast molded body.
The obtained cast molded body 80 has a cast structure. For example, by using a mold having a cooling mechanism such as a water cooling pipe inside the wall surface, the cast cast body 80 exhibits a rapidly solidified structure that is rapidly cooled and solidified. A rapidly solidified molded body can be obtained. The cast molded body 80 may be used as a member constituting various devices as it is. However, a shaping process S5 for shaping the size and shape of the cast molded body 80 is further performed in consideration of connection to other members and the like. It may be 50. Examples of the shaping means include cutting with a milling machine, grinding with a grindstone, and polishing.

<Alloy products>
The Cr—Ni alloy produced as described above can achieve both corrosion resistance and wear resistance (earth and sand wear resistance).
As a result, the Cr—Ni alloy product of the present disclosure can be suitably used as various members used in severe corrosive environments and wear environments. The applicable members include automobile members (for example, fuel injection device members, roller chain members, turbocharger members, engine exhaust system members, bearing members), railway-related members (for example, bearing members, pantograph members), rolling Bearings and plain bearing members (eg linear bearing members, windmill bearing members, water wheel bearing members, ventilation fan bearing members, mixing drum bearing members, compressor bearing members, elevator bearing members, escalator bearing members, planetary explorer bearing members) and construction Equipment members (for example, endless track members, mixing drum members), marine and submarine members (for example, screw members), environmental equipment members (for example, garbage incinerator members, crushing machines), bicycles, motorcycles, Water bike components (eg, roller chain members, Procket members), machining device members (for example, dies, rolling rolls, cutting tool members), oil well equipment members (for example, members (shafts, bearings) of rotating machines (compressors, pumps)), seawater Environmental equipment members (for example, seawater desalination plant equipment members, umbilical cables), chemical plant equipment members (for example, liquefied natural gas vaporizer members), power generation equipment related members (eg, coal gasifier members, heat-resistant piping members) , Fuel cell separator member, fuel reforming device member) and the like. Among the above-mentioned members, application to oil well equipment members, machining devices, and environmental equipment members is particularly preferable.

FIG. 4A is an example of a Cr—Ni based alloy product according to the present disclosure and an industrial product using the same, and a fluid such as crude oil containing a corrosive component such as organic acid including earth and sand (solid matter). It is a cross-sectional schematic diagram of the screw pump used by conveyance of. In the screw pump, for example, the Cr surface of the present disclosure is used as an alloy coating layer such as a screw surface and a casing surface that are in contact with a conveyed object to be conveyed, and an inner surface of a piping member connected to a suction port or a discharge port (not shown). -Ni-based alloy products can be suitably used. The alloy coating layer can be manufactured in the form of an overlay welding material.
FIG. 4B is a cross-sectional schematic diagram of an injection mold as another example of the Cr—Ni alloy product of the present disclosure and an industrial product using the same. In an injection mold, for example, an alloy coating layer on the surface of a mold base that is in contact with molten plastic or a mixture of metal powder and a binder, which is filled in a space provided between an upper mold and a lower mold As a result, the Cr—Ni alloy product of the present disclosure can be suitably used. The alloy coating layer can be manufactured in the form of an overlay welding material.
FIG. 4 (c) is another example of the Cr—Ni alloy product of the present disclosure and an industrial product using the same, and crushing is performed between tooth plates that rock the object to be conveyed such as rock and concrete waste. It is a cross-sectional schematic diagram of the crushing machine called a jaw crusher. In the crushing machine, for example, the Cr—Ni-based alloy product of the present disclosure can be suitably used as an alloy coating layer on the surface of the fixed tooth plate and the movable tooth plate contacting the object to be crushed such as rock. The alloy coating layer can be manufactured in the form of an overlay welding material.
In the application example to the industrial product, the example in which the alloy coating layer is provided on the surface of the target member has been described. However, the entire target member may be formed of the Cr—Ni alloy product of the present disclosure.

Hereinafter, the present disclosure will be described more specifically with reference to examples and comparative examples. Note that the present disclosure is not limited to these examples.
(Test specimen characteristic evaluation method)
(1) Evaluation of abrasion resistance (earth and sand abrasion resistance) Equipment for crude oil mining is subject to wear due to gravel in the crude oil that comes into contact with it. Therefore, a soil wear test was performed as an abrasion resistance evaluation. The test method conformed to ASTM standard G65. After measuring the pre-test weight of the test piece that was cut and polished the molded body of each composition, with the rotating rubber disc pressed against the test piece with a predetermined load, test silica sand was placed between the contact surfaces of both. Feed continuously for 10 minutes. Thereafter, the weight of the test piece was measured to determine the mass change before and after the test, and the wear volume AVL (unit: mm ³ ) was calculated in consideration of the change in diameter due to the wear of the rubber disk accompanying the test.
As a result of measuring the wear volume, “AVL <180” was evaluated as A grade, “180 ≦ AVL <360” as B grade, and “360 ≦ AVL” as C grade. The results of soil and sand abrasion resistance evaluation are shown in Tables 1 to 4.

(2) Corrosion resistance evaluation Equipment for crude oil mining, which is assumed as an application field of this disclosure, has a strong acid corrosion environment due to the effects of hydrogen sulfide contained in crude oil and hydrochloric acid generated by the decomposition of inorganic chlorides. Be exposed. Then, the boiling sulfuric acid immersion test was implemented as corrosion resistance evaluation. The test method conformed to JIS standard G0591: sulfuric acid corrosion test method for stainless steel, and the test solution was diluted with sulfuric acid having a pH of 1 with pure water to a concentration of 5% by mass. The test piece obtained by cutting and polishing the molded body of each composition was measured for pre-test weight and then immersed in a boiling test solution for 6 hours. Thereafter, the test piece mass is measured to determine the mass change before and after the test, and the value obtained by dividing the change by the test piece surface area and test time before the test is calculated as the corrosion rate m (unit: g / (m ² · h)). did.
Corrosion rate measurement results were evaluated as “m <3 × 10 ⁰ ” as A grade, “3 × 10 ⁰ ≦ m <10 ² ” as B grade, and “10 ² ≦ m” as C grade. The results of the corrosion resistance evaluation are shown in Tables 1 to 4.
(3) Microstructure observation In order to investigate the relationship between the corrosion resistance and the earth and sand abrasion resistance, the cut surfaces of some test pieces were mirror-polished and observed with a scanning electron microscope (SEM).

[Example 1]
The raw materials were mixed so as to have the composition shown in Table 1, and melted by a high-frequency melting method (melting temperature 1500 ° C. or higher, in a reduced pressure Ar atmosphere) to form a molten metal, and then the molten metal was cast to prepare a cast molded body. In the overlaying material to which the alloy of the present disclosure is applied, the cooling rate at the time of overlaying is high, so the mold to be used is selected to have an elongated shape with a diameter of about 20 mm, and the structure of the cast molded body is the overlay welding bead. I tried to become a near quenching organization. Each cast molded body was cut and polished into a predetermined test piece shape according to each test method described above. No. shown in Table 1. 1-4 are comparative examples in which C was fixed at 1.0%. Nos. 5 to 8 were compositions of the present invention examples in which C was increased to 2.0 to 2.9%. No. Nos. 9 to 14 were compositions of the present invention examples in which Cr was about 55% or about 60%, and compositions other than C were generally fixed, and C was changed to 1.5 to 2.5%. No. No. 15 is a comparative example in which C is increased to 4.5%. 16 is a composition of the present invention example in which Cr is reduced to 45.0%. In addition, what is shown as “<0.1%” is a very small amount of less than 0.1%.

FIG. 5 shows the test results of the corrosion rate m and the wear volume AVL in each test piece. The numbers with circles written beside each plot indicate the No. of each composition shown in Table 1. It corresponds to.
For soil and sand abrasion resistance, Comparative Example No. C with 1.0% by mass was used. Alloys 1 to 4 are all judged to be C grade and have poor soil and sand resistance. 6 and FIG. 1 to 4 show scanning electron microscope (SEM) images of alloys No. 1 to No. 4. One alloy has a two-phase structure in which an island-like phase exists in a phase having a fine eutectic structure. No. All of the alloys 2 to 4 had a structure in which fine crystals or precipitates were dispersed throughout, which are considered to be carbides. Here, no. No. 2 alloy and No. 2 When compared with No. 4 alloy, no. In the alloy 2, a gray portion extending linearly is seen in a matrix that appears white, but its length is as short as several μm. On the other hand, no. The structure of Alloy 4 is No. Similar to Alloy 2, but the gray portion extending linearly is as long as several tens of micrometers. It is thought that the carbide grew compared to the two alloys. The reason why such a difference in structure appears is due to the balance between Ni and Fe, but it is considered that the carbide width was as thin as 1 μm or less in any composition, and did not contribute to the improvement of soil and sand resistance.

On the other hand, no. In the case of 5 to 16 alloys, the earth and sand abrasion resistance of all alloys achieved A grade; AVL <180. Here, in FIG. 5 and no. No. 6 alloy, No. 6 in FIG. 7 and no. The SEM observation image of 8 alloy is shown. In any of the images, unlike the case of containing 1.0% by mass of C shown in FIGS. 6 and 7, the massive carbides having a size exceeding about 20 μm and displayed in dark gray or black are dispersed. I understand that As a result of analyzing this massive carbide with an X-ray analyzer, it was a Cr-based carbide containing Cr as a main component. It is considered that this massive Cr carbide crystallizes and grows in the liquid phase of the alloy melted at the time of overlaying and remains dispersed in the structure when it is rapidly cooled and solidified. .
Here, when the relationship between the amount of massive carbide occupying the observation region and the earth and sand abrasion resistance is observed, No. in which no massive carbide appears. Alloys 1 to 4 have AVL> 400, whereas No. 1 with a large amount of carbides. Alloys 5 to 8 have a range of AVL <180, and it is considered that earth and sand abrasion resistance was improved by increasing the amount of massive carbides in the structure.
In addition, the difference in the color tone of the carbides indicates that the carbide forms of the two are different. The region that appears black is M ₇ C ₃ type Cr carbide, and the region that appears dark gray is M ₂₃ C ₆ type Cr. It is considered to be carbide. It is considered that the Vickers hardness of each form of Cr carbide exceeds 1000, and both contribute to the improvement of soil and sand wear resistance.
On the other hand, no. No. 16 had a lower Cr content than other examples of the present invention, and the B blade was evaluated. 1 to 4 and the comparative example No. described below. Compared with 51-56, it is equivalent or better. In addition, when C is included more than 1.1 mass%, it is preferable that Cr is more than 46.0%.

Next, in FIG. 2 shows SEM observation images of alloys 9-11. From the color tone of the image, all are considered to be M ₇ C ₃ type carbides. No. 9 containing 2.0% by mass of C, whereas the carbide size of alloy No. 9 is approximately 15 μm. The size of the carbide of alloy No. 10 is approximately 20 μm, and No. 10 containing 2.5% by mass of C. The size of the carbide of the eleventh alloy is approximately 30 μm, and the proportion of the carbide in the observation region is increasing. Here, referring to FIG. 9, no. 10, no. The wear volume AVL decreases in the order of 11 alloys, and it is considered that the earth and sand wear resistance is improved by increasing the carbide in the structure.
Next, in FIG. The SEM observation images of Alloys 12 to 14 are shown. 12 and no. The carbide of alloy No. 13 is M ₂₃ C ₆ type, no. 14 alloy is considered to be mainly M ₇ C ₃ type. Both have different carbide forms and individual sizes, but the more C, the greater the proportion of carbide in the structure, which is considered to be the difference in soil and sand resistance.
In addition, according to the examination by the inventors using an equilibrium diagram calculation or the like, the carbide in the alloy of the present disclosure when C is relatively small is M ₂₃ C ₆ type, and when C increases, M ₇ C ₃ type appears. As M ₇ C ₃ appears, the more Cr, the more C is required. Comparing FIG. 10 and FIG. 11, the carbide in FIG. 10 in which Cr is 55% by mass is M ₇ C ₃ type, whereas the carbide in FIG. 11 in which Cr is 60% by mass is mostly M ₂₃ C ₆ type. It occupies a part and matches well with the above-mentioned tendency.

[Example 2]
The raw materials were mixed so as to have the composition shown in Table 2 and melted by a high-frequency melting method (melting temperature 1500 ° C. or higher, in a reduced pressure Ar atmosphere) to form a molten metal, and then the molten metal was cast to prepare a cast molded body. In the overlaying material to which the alloy of the present disclosure is applied, the cooling rate at the time of overlaying is high, so the mold to be used is selected to have an elongated shape with a diameter of about 20 mm, and the structure of the cast molded body is the overlay welding bead. I tried to become a near quenching organization. Each cast molded body was cut and polished into a predetermined test piece shape according to each test method described above. No. shown in Table 2. Nos. 21 to 26 and 28 are compositions of the examples of the present invention. 27 is a comparative example in which B deviates from the upper limit. These abrasion resistance (earth and sand abrasion resistance) evaluation, corrosion resistance evaluation, and structure observation were performed in the same manner as in Example 1. In addition, what is shown as “<0.1%” is a very small amount of less than 0.1%.

FIG. 12 shows the test results of the corrosion rate m and the wear volume AVL in each test piece. The numbers in parentheses beside each plot indicate the No. of each composition shown in Table 2. It corresponds to.
Regarding the earth and sand abrasion resistance, No. of the present invention example. The 21-26 alloy achieved a sand abrasion resistance of A grade; AVL <180. Here, FIGS. 13 to 15 show the examples of the present invention. The SEM observation image of each alloy of 21-26 is shown. In any of the images, a massive boride having an elongated cross-sectional shape having a size of more than 3 μm in the width direction and more than 30 μm in the longitudinal direction is dispersed in black. As a result of analyzing this massive boride with an X-ray analyzer, it was a Cr-based boride containing Cr as a main component. It is thought that this massive Cr boride crystallizes and grows in the liquid phase of the alloy melted at the time of overlaying and remains dispersed in the structure when it is rapidly cooled and solidified. It is done.
This massive Cr boride is a hard material whose Vickers hardness is considered to exceed 1000, and it is considered that the increase in the hard Cr boride contributed to the improvement of the earth and sand abrasion resistance.
Next, comparative example No. B whose B is 4.0 mass%. In Alloy 27, the earth and sand abrasion resistance achieved A grade, but the corrosion resistance was very bad as C grade. An SEM observation image is shown in FIG. No. 21-26 No. 27 has the most Cr boride dispersed therein. From this, No. In No. 27, it is considered that a larger amount of Cr was consumed at the time of crystallization of the Cr boride, and the Cr in the other parent phase was reduced to deteriorate the corrosion resistance.
Next, Example No. of the present invention in which Cr is 42.0%. Alloy 28 was B grade in both corrosion resistance and wear resistance. An SEM observation image is shown in FIG. Compared with 21-26, the individual Cr borides were thin and short. This is thought to be because the amount of Cr boride crystallized was reduced by the small amount of Cr, and the amount of Cr originally contained in the parent phase was small. This No. No. 28 is inferior to other examples of the present invention, but the comparative example No. 28 described below. Compared with 51-56, it is equivalent or better. In addition, when comprising a Cr boride, it is preferable that Cr amount is 45% or more.

Example 3
The raw materials were mixed so as to have the composition shown in Table 3 and melted by a high-frequency melting method (melting temperature 1500 ° C. or higher, in a reduced pressure Ar atmosphere) to form a molten metal, and then the molten metal was cast to prepare a cast molded body. In the overlaying material to which the alloy of the present disclosure is applied, the cooling rate at the time of overlaying is high, so the mold to be used is selected to have an elongated shape with a diameter of about 20 mm, and the structure of the cast molded body is the overlay welding bead. I tried to become a near quenching organization. Each cast molded body was cut and polished into a predetermined test piece shape according to each test method described above. No. shown in Table 3 Nos. 31 to 35 are examples of the present invention in which C was fixed at 1.0%. Nos. 36 and 37 have C over 1.0%. 38 and 39 are examples of the present invention in which C is less than 1.0%. No. 40 is an example of the present invention in which 2.2% of C is added so as to increase the ratio of C to Nb. No. 41 is No. 41. This is an example of the present invention having a composition similar to that of No. 34 and increasing both of them while maintaining the ratio of Nb and C at 8: 1. These abrasion resistance (earth and sand abrasion resistance) evaluation, corrosion resistance evaluation, and structure observation were performed in the same manner as in Example 1.

FIG. 18 shows the test results of the corrosion rate m and the wear volume AVL for each test piece. The numbers in parentheses written beside each plot indicate the No. of each composition shown in Table 3. It corresponds to.
Both alloys were judged to be A grade in both earth and sand wear resistance and corrosion resistance, and good characteristics were obtained. 19 to 23 show scanning electron microscope (SEM) observation images of the alloys of the present invention. Alloy 31 has masses, rods, and crystallization or precipitates of 20 μm or less visible with white contrast, and the parent phase has a ferrite phase that appears dark gray contrast and an island-like austenite phase that appears light gray contrast It was a two-phase structure.
No. Similarly, all 32 alloys had a structure in which crystals or precipitates spread in a lump shape, rod shape, dot shape, feather shape, and dendritic shape of 20 μm or less that appeared in white contrast were dispersed throughout. As a result of analysis by EDX and X-rays of these portions that appear with white contrast, they were Nb-based carbides containing Nb as a main component. In addition, among the two-phase structure, a part of the island-like austenite phase has a eutectic structure that appears with black contrast, and as a result of analysis by EDX or X-ray, it is a Cr-based carbide containing Cr as a main component. there were.
On the other hand, no. No. 33 alloy also has Nb-based carbides that can be seen with white contrast. No massive Nb-based carbides of about 10 μm like the

alloys

1 and 2 were found, and the structure was a structure in which crystallized substances or precipitates spread in a rod-like, dot-like, feather-like, and dendritic shape of 20 μm or less were dispersed.

Similarly, FIGS. 20 to 23 show the examples of the present invention. SEM observation images of alloy structures 34 to 41 are shown. Similar to 31 to 33, it was a structure in which crystallization or precipitates spread in a lump shape, rod shape, dot shape, feather shape and dendritic shape were dispersed throughout. All of these alloys were also judged to be A grade in both earth and sand wear resistance and corrosion resistance, and good characteristics were obtained.
By the way, when hard particles (Nb carbide) are dispersed in the structure to suppress wear, the effect is reduced if the strength of the hard particles themselves is low. Therefore, it is desirable that the hard particles are in a large size. I think that the. However, for example, alloy no. In No. 33, although eutectic Nb-based carbides are mostly present and no massive Nb-based carbides are observed, the soil wear resistance is better than that of other alloys of the present disclosure. This is because, in the alloy of the present disclosure, Nb-based carbides are present in the hard ferrite phase in the two-phase structure constituting the parent phase, and therefore the ferrite phase supplements the strength of the Nb-based carbides. It is considered that the region acts as virtual hard particles.
Therefore, it is considered that the wear resistance of the alloy of the present disclosure is influenced not only by the number and size of the massive Nb-based carbides but also by the total area, distribution state, and shape of the Nb-based carbide phase. For the SEM photographs of each alloy taken from a plurality of fields of view including the SEM photographs of FIGS. 19 to 23, the Nb-based carbide part visible in white contrast and the other parts are binarized by image analysis software. When the area ratio of the entire field of view was calculated, it was approximately in the range of 6 to 20%.

According to the study using the equilibrium diagram calculation by the inventors, Cr-based carbides appear in the alloy of the present disclosure not only when there is a large amount of Cr but also when C is excessively added to Nb. In this case, the Cr-based carbide is mainly M ₂₃ C ₆ type. No. In

alloys

32, 33, and 36, eutectic Cr-based carbides appear in the austenite phase, and the ratio of C to Nb is increased. In No. 40, elongated massive Cr-based carbides appear. These Cr-based carbides are hard and contribute to wear resistance in the same way as Nb-based carbides. On the other hand, the formation of Cr-based carbides consumes Cr in the parent phase, which may deteriorate the corrosion resistance. There is. Therefore, care must be taken so that the amount of C added does not become excessive.

[Comparative example]
In order to compare the level of corrosion resistance and wear resistance (earth and sand wear resistance) in the Cr—Ni-based alloy of the present disclosure, four types of powders having compositions corresponding to commercially available surfacing materials for surface modification shown in Table 4, Using two types of Cr-based alloys (50Cr, 63Cr) with no addition of C, B, Nb, a test piece is prepared by cutting and polishing the weld beads formed and formed on the SUS304 base material using a PTA overlay welding machine. Then, a boiling sulfuric acid immersion test and a sediment wear test were conducted. Each test condition was the same as that shown in the above-described test piece characteristic evaluation method. Table 4 shows the results of the composition, corrosion resistance, and earth and sand wear resistance of the commercially available cladding material and the comparative example Cr-based alloy, and FIG. 24 shows the test results of the corrosion rate and sediment wear volume of each cladding material.
In the overlay material compared this time, there was no material which achieved A grade in both corrosion resistance and earth and sand wear resistance. Commercially available No. It can be seen that the alloy of the present disclosure achieves both corrosion resistance and earth and sand wear resistance equivalent to or better than 51 to 54.

The above-described embodiments and examples are described for the purpose of helping understanding of the present invention, and the present invention is not limited to the specific configurations described. For example, it is possible to replace a part of the configuration of the embodiment with the configuration of common technical knowledge of those skilled in the art, and it is also possible to add the configuration of technical common sense of those skilled in the art to the configuration of the embodiment. That is, according to the present invention, a part of the configurations of the embodiments and examples of the present specification may be deleted, replaced with other configurations, and added with other configurations without departing from the technical idea of the invention. Is possible.

DESCRIPTION OF SYMBOLS 10 ... Molten metal 11 ... Consumable electrode 12 ... Cleaning molten metal 20 ... Alloy powder 40 ... Overlay welding material 41 ... Base material 42 ... Alloy coating layer 50 ... Shaped body 60 ... Powder molded body 70 ... Powder metallurgy molded body 80 ... Cast molding body

Claims

% By mass
More than 40.0% and 65.0% or less of Cr,
0% or more and 35.0% or less of Fe;
Mn from 0% to less than 2.0%,
Including any of the following (1) to (3),
(1) C over 1.1% and 4.0% or less
(2) 0.7% to 3.0% B
(3) C of 0.5% or more and 2.5% or less and Nb of more than 0% and 20% or less
A Cr—Ni alloy in which the balance is made of Ni and inevitable impurities, and the Ni is 15% or more.
% By mass
46.0% to 65.0% Cr,
0.1% or more and 30.0% or less of Fe;
More than 0% and less than 2.0% Mn,
1.1% to 4.0% or less of C,
The Cr—Ni alloy according to claim 1, wherein the balance is made of Ni and inevitable impurities.
% By mass
45.0% or more and 65.0% or less of Cr;
0.1% or more and 35.0% or less of Fe;
More than 0% and less than 2.0% Mn,
0.7% or more and 3.0% or less of B,
The Cr—Ni alloy according to claim 1, wherein the balance is made of Ni and inevitable impurities.
% By mass
More than 40.0% and 65.0% or less of Cr,
Fe of 0% or more and 30.0% or less;
0.5% or more and 2.5% or less of C and more than 0% and 20% or less of Nb,
The Cr—Ni alloy according to claim 1, wherein the balance is made of Ni and inevitable impurities.
% By mass
0.1% or more and 1.0% or less of Si,
0.005% or more and 0.05% or less of Al,
0.02% to 0.3% Sn,
0.1% or more and 5.0% or less of Cu,
The Cr—Ni alloy according to claim 1, comprising at least one of the following.
The Cr-Ni alloy according to any one of claims 1 to 5, wherein the Cr-Ni alloy has a ferrite phase and / or an austenite phase.
A rapidly solidified molded body made of the Cr-Ni alloy according to any one of claims 1 to 6.
An alloy powder comprising the Cr-Ni alloy according to any one of claims 1 to 6.
A powder metallurgical compact comprising the Cr-Ni alloy according to any one of claims 1 to 6.
A cast molded body made of the Cr-Ni alloy according to any one of claims 1 to 6.
A method for producing a Cr-Ni alloy according to any one of claims 1 to 6,
A melting step of melting a raw material of the Cr-Ni alloy to form a molten metal;
And an atomizing step for producing an alloy powder from the molten metal.
A method for producing a Cr-Ni alloy according to any one of claims 1 to 6,
A melting step of melting a raw material of the Cr-Ni alloy to form a molten metal;
A casting step of casting the molten metal to form a cast molded body;
A pulverization step of mechanically pulverizing the cast compact to produce an alloy powder.
A method for producing a Cr-Ni alloy according to any one of claims 1 to 6,
A powder forming step of forming a powder compact by performing press molding or injection molding using the powder made of the Cr—Ni alloy as a raw material, and firing the powder compact at a temperature lower than the solidus temperature of the alloy. And a sintering step of forming a powder metallurgy molded body by performing a heat treatment.
A method for producing a Cr-Ni alloy according to any one of claims 1 to 6,
A melting step of melting a raw material of the Cr-Ni alloy to form a molten metal;
And a casting step of casting the molten metal to form a cast molded body.
A mechanical facility for transporting or processing a transported object containing a solid material and / or a corrosive component, which constitutes the mechanical facility and contacts the transported object of the member itself or the transported object of the member A mechanical equipment, wherein at least a part of the surface is made of the Cr-Ni alloy according to any one of claims 1 to 6.
It is a piping member used for the conveyance path | route of the to-be-conveyed object containing a solid substance and / or a corrosive component, Comprising: At least one part of the surface which contacts the said to-be-conveyed object of the said piping member itself or the said piping member is 1 thru | or 1. A piping member made of the Cr—Ni-based alloy according to claim 6.