JP2006283176A - Water-cooled steel pipe structure having excellent corrosion resistance and wear resistance, and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance to atmospheres of high temperature corrosion, erosion wear and dew point corrosion, e.g., in converter exhaust gas treatment equipment of a steel making workshop. <P>SOLUTION: A film material obtained by blending an Ni-based self-fluxing alloy comprising, by mass, 10 to 20% Cr, 2 to 4.5% B, 2 to 5% Si, 0.4 to 1.1% C, ≤5% Fe, ≤1% Co, ≤4% Mo and ≤4% Cu, and the balance Ni with an Ni-based alloy comprising 20 to 23% Cr, 8 to 10% Mo, 2 to 7% Fe and 1 to 4% (Nb+Ta), and the balance Ni with inevitable impurities by 10 to 90% is thermally sprayed on the surface of a water-cooled steel pipe structure, and remelting treatment is performed, so as to form a film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a water-cooled steel pipe structure that has long-term durability against high-temperature corrosion and wear due to high-temperature exhaust gas and dust containing chlorine and the like in an exhaust gas treatment facility in a converter of a steelmaking factory and a boiler facility in a power plant. About.

In an exhaust gas treatment facility for a converter in a steelmaking factory, a skirt 2, a lower hood 3, and an upper hood 4 as shown in FIG. 1 are used to recover sensible heat of high-temperature exhaust gas and useful components as a heat source contained in the exhaust gas. -A water-cooled steel pipe structure having a name such as the dust collection duct 5 is formed.
These water-cooled steel pipe structures have significant erosion wear due to high-temperature corrosion caused by high-temperature exhaust gas containing components such as Cl during use and collision of dust generated during blowing from molten steel and various ores that are added as auxiliary materials. Will occur.

In addition, corrosive gases such as Cl and S generated from iron scrap and auxiliary materials mixed with resins, high-temperature corrosion due to high-temperature oxidation, and thermal fatigue due to repeated intermittent operation also occur. If the steel pipe structure is damaged by thinning wear and cracks due to these high-temperature corrosion, wear and thermal fatigue, and cooling water and water vapor flowing into the pipe of the pipe structure leaks out, heat recovery becomes impossible. Otherwise, a steam explosion may occur due to the reaction between high-temperature molten steel and leaked water, resulting in a serious accident.
In view of the above situation, the facility was periodically stopped to repair the high-temperature exhaust gas contact surface of the water-cooled steel pipe structure, which was a factor in reducing productivity.

In order to solve these problems, in Patent Document 1, a method of forming a coating excellent in heat resistance and wear resistance by spraying carbide cermet on the surface of a water-cooled steel pipe and then spraying MCrAlX alloy. Has been proposed.
In Patent Document 2, a base sprayed coating of a refractory metal or its alloy or carbide cermet is formed on the surface of a substrate such as a cooling pipe, and a porous inorganic coating is applied as necessary, and then chromic acid and phosphoric acid are mainly used. There has been proposed a composite sprayed member in which a sealing agent as a component is applied, dried and then heated and fired to form a glassy chromium oxide film as an upper layer.
In Patent Document 3, a protective film is formed by forming a film of a self-fluxing alloy powder such as Ni-base or Co-base on the wall surface of a cooling pipe by high-pressure, high-speed gas spraying, and re-melting it to adhere to the wall surface. A method has been proposed.
Japanese Patent Laid-Open No. 7-18320 Japanese Patent No. 3039850 JP 2005-8921 A

However, the above technique has the following problems.
In the techniques described in Patent Document 1 and Patent Document 2, thermal spraying methods such as gas spraying, high-speed gas spraying, and plasma spraying are used for forming the sprayed coating. The adhesion mechanism between the surface and the thermal spray coating is due to the mechanical anchoring effect, and the adhesion with the substrate is insufficient, and there is a problem of peeling in a short period during use.
Moreover, the coating film by the technique described in Patent Document 3 has insufficient durability against high temperature corrosion caused by exhaust gas. In addition, since this method combines spraying with a high-pressure / ultra-high-speed spray gun and remelting treatment, there is also a problem of high cost.

  In view of the above problems, the present invention forms a film having long-term durability against high-temperature corrosion and wear caused by high-temperature exhaust gas and dust containing chlorine, etc. The purpose of this plant is to provide a water-cooled steel pipe structure that enables long-term operation of boiler facilities, reduces maintenance costs, and improves operating rates.

  In order to achieve the above object, the present inventor has extensively studied a coating film that is durable against high temperature exhaust gas containing chlorine or the like, high temperature corrosion due to dust, and wear in a high temperature range. As a result, the material having both high adhesion and wear resistance to the base material is a self-fluxing alloy, and the high corrosion resistance against high temperature exhaust gas containing chlorine or the like and high temperature corrosion due to dust is As a result of finding a Ni alloy having a specific composition and making various thermal sprayed coatings and evaluating them, the present invention has been completed.

The present invention has been made on the basis of the above findings, and the gist thereof is as follows.
(1) By mass
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
In the Ni-based self-fluxing alloy which is the remaining Ni alloy,
Cr = 20-23%, Mo = 8-10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A material containing 10 to 90% by mass of the remaining Ni and an inevitable impurity Ni-based alloy is used as a thermal spray material, and the thermal spray material is sprayed on a base material and has a film formed by remelting treatment. A method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance.
(2) The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
The method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (1) above, wherein the alloy is composed of the balance Ni and inevitable impurities.
(3) The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
The method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (1) above, wherein the alloy is composed of the balance Ni and inevitable impurities.

(4) By mass,
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
The Ni-based self-fluxing alloy, which is the remaining Ni alloy, is sprayed as a lower layer coating on the base material, and the Ni-based self-fluxing alloy is mass-coated on the surface of the coating.
Cr = 20-23%, Mo = 8-10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A material in which the alloy composed of the balance Ni and inevitable impurities is blended in an amount of 10 to 90% is used as a thermal spray material for the upper coating, and this thermal spray material is sprayed to form one or more layers and remelted. A method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance, comprising a formed coating.
(5) The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
The method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (4) above, wherein the alloy is composed of the balance Ni and inevitable impurities.
(6) The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
The method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (4) above, wherein the alloy is composed of the balance Ni and inevitable impurities.
(7) The Ni-based self-fluxing alloy further has a mass,
Fe = 5% or less, Co = 1% or less,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance according to the above (1) or (4), characterized by containing one or more of Mo = 4% or less and Cu = 4% or less Production method.

(8) By mass,
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
In a Ni-based self-fluxing alloy that is an alloy of the balance Ni, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A water-cooled steel pipe structure excellent in corrosion resistance and wear resistance, characterized by having a coating containing 10 to 90% of a Ni-based alloy consisting of the balance Ni and inevitable impurities dispersed in mass.
(9) The Ni-based alloy dispersed and contained in the self-fluxing alloy is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (8) above, which is an alloy comprising the remaining Ni and inevitable impurities.
(10) The Ni-based alloy dispersed and contained in the self-fluxing alloy is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (8) above, which is an alloy comprising the remaining Ni and inevitable impurities.

(11) By mass,
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
In the lower layer coating of the Ni-based self-fluxing alloy that is the remaining Ni alloy, and in the self-fluxing alloy, Cr = 20 to 23%, Mo = 8 to 10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A water-cooled steel pipe structure excellent in corrosion resistance and wear resistance, comprising an upper layer film containing 10 to 90% of a Ni-based alloy composed of the balance Ni and inevitable impurities dispersed therein. (12) The Ni-based alloy dispersed and contained in the self-fluxing alloy as the upper layer coating is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (11) above, which is an alloy composed of the remaining Ni and inevitable impurities.
(13) The Ni-based alloy dispersed and contained in the self-fluxing alloy as the upper layer coating is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (11) above, which is an alloy composed of the remaining Ni and inevitable impurities.
(14) The Ni-based self-fluxing alloy is further in mass%,
Fe = 5% or less, Co = 1% or less,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance as described in (8) or (11) above, which contains one or more of Mo = 4% or less and Cu = 4% or less.

  According to the present invention, a coating film having a long-term durability against high-temperature corrosion and wear due to high-temperature exhaust gas or dust containing chlorine or the like is formed, and an exhaust gas treatment facility in a converter of a steelmaking factory or a boiler of a power plant Equipment can be operated for a long period of time, maintenance costs can be reduced, and the operating rate can be improved.

The present inventor evaluated various materials on a trial basis for the purpose of providing a coating that is durable against high temperature exhaust gas and dust containing high temperature corrosion caused by chlorine and the like, and wear in a high temperature range. Both high adhesion and wear resistance, and high corrosion resistance against high temperature exhaust gas and dust containing chlorine, etc., are based on Ni-based self-fluxing alloys and Ni alloys with a specific composition. It was found that the film was formed by thermal spraying and remelting a material containing 10 to 90% by mass.
Hereinafter, embodiments of the present invention will be described in detail.

The present invention is a water-cooled steel pipe structure having a coating formed by spraying a material in which a Ni-based self-fluxing alloy is blended with an alloy having a specific composition of Ni-based by 10 to 90% by mass and then remelting. is there. The Ni-based alloys having the composition having the above characteristics are the following three types.
In the following description, the Ni-based alloy refers to an alloy having the following two types of compositions.
(1) An alloy of Cr = 20-23%, Mo = 8-10%, Fe = 2-7%, (Nb + Ta) = 1-4% and the balance Ni by mass.
(2) An alloy of Cr = 20-23%, Mo = 8-10%, Fe = 2-7% and the balance Ni by mass.
Specific preferred composition examples of the above alloys are:
Inconel (registered trademark) 625: Bal Ni-9Mo-21.5Cr-2.5Fe-3.7Nb (unit: mass%)
It is.
(3) Alloy of Cr = 14-17%, Mo = 15-17%, W = 3-5%, Fe = 4-7%, balance Ni by mass.
Specific preferred composition examples of the above alloys are:
Hastelloy (registered trademark) C276: Bal Ni-16Mo-16Cr-4W-5Fe-0.005C-0.05Si (unit: mass%)
It is.
The Ni-based alloy is extremely excellent in corrosion resistance against high-temperature corrosion caused by high-temperature exhaust gas or dust containing chlorine or the like. However, the hardness is about HV200, and it does not have sufficient wear resistance against erosion wear caused by collision of scattered dust.

The Ni-based self-fluxing alloy is an alloy in which B, Si, etc. are added based on the eutectic composition of Ni and Cr, and after thermal spraying, it is heated at about 940 to 1100 ° C. and re-melted, It is a thermal spray material that can improve the adhesion by bringing the adhesion surface with the coating into a metallurgical bonding state. In the JIS H8303 standard, five types of compositions of standard symbols SFNi1 to SFNi5 are defined according to the hardness of the film after remelting.
The composition of the Ni-based self-fluxing alloy is
By mass, Cr = 10 to 20%, B = 2 to 4.5%, Si = 2 to 5%, C = 0.4 to 1.1%, Fe = 5% or less (including 0%), Co = 1% or less (including 0%), Mo = 4% or less (including 0%), Cu = 4% or less (including 0%), and the balance Ni.

In the coating of the water-cooled steel pipe structure according to the present invention, among the Ni-based self-fluxing alloys, SFNi4 having a high coating hardness and easy remelting treatment is a preferred composition.
The specific composition of SFNi4 is
Cr = 12-17%, B = 2.5-4.0%, Si = 3.5-5.0%, C = 0.4-0.9%, Fe = 5% or less (including 0%) ), Co = 1% or less (including 0%), Mo = 4% or less (including 0%), Cu = 4% or less (including 0%), and the balance Ni.
However, the composition of the Ni-based self-fluxing alloy used in the present invention is not limited to the above SFNi4.
In the composition of the Ni-based self-fluxing alloy, Fe, Co, Mo, and Cu are arbitrarily added elements, and each of them is expressed as “including 0”.

As a thermal spraying method for forming a Ni-based alloy coating on a substrate, a gas spraying method, an arc spraying method, a plasma spraying method, or the like is used. In the coating of the present invention, a powder gas that is inexpensive and easy to work with. The objective can be sufficiently achieved by the thermal spraying method.
In gas spraying, there are generally many pores in the coating, and it is difficult to obtain a dense coating if sprayed as it is. However, in the sprayed coating containing the Ni-based self-fluxing alloy in the present invention, re-melting treatment is performed after spraying. The inner pores disappear, and at the same time, metallurgical bonding occurs with the base material, so that it is possible to form a coating film that is dense and has extremely high adhesion to the base material and high hardness.

  In the present invention, the Ni-based self-fluxing alloy is blended with 10 to 90% by mass of any of the above three types of Ni-based alloys to form a thermal spray material, and this thermal spray material is sprayed onto the base material and remelted. By performing the treatment, it is possible to form a film having both corrosion resistance against high-temperature corrosion caused by high-temperature exhaust gas and dust containing chlorine and the like, and wear resistance against erosion caused by collision of scattered dust.

Next, the form of the film of the present invention will be described with reference to FIG.
Fig.2 (a) is sectional drawing which shows 1 form of the film of the water-cooled steel pipe structure formed by this invention. The structure is such that the Ni-based alloy 8 particles are dispersed in the Ni-based self-fluxing alloy 7 in close contact with the surface of the substrate 6.
The finer the particles of the Ni-based alloy 8 are, the higher the homogeneity of the coating material is, and it is preferable, but it has been confirmed that sufficient performance is exhibited if it is 1 mm or less. Usually, the particle size is determined by the particle size of the thermal spray powder. The particle size suitable for thermal spraying is in the range of 10 μm or more and 100 μm or less, but in many cases, a thermal spray powder having a particle size range of 10 μm or more and 50 μm or less is used. Thereby, the particle diameter of the Ni-based alloy 8 in the film formed by the method of the present invention is in the range of 10 μm or more and less than 1 mm.

This coating can easily control the corrosion resistance and wear resistance by changing the blending ratio of the Ni-based alloy 8 to the Ni-based self-fluxing alloy 7. In order to obtain a coating film with a focus on wear resistance, it is desirable that the mixing ratio of the Ni-based alloy 8 is 10 to 50% by mass. Further, in order to obtain a film having a characteristic with an emphasis on corrosion resistance, it is desirable that the mixing ratio is 30 to 90% by mass.
The thicker the film, the more advantageous it is in terms of corrosion and wear, but if it is too thick, it may cause cracking of the film due to the influence of deformation of the substrate, thermal shock, or temperature difference between the inner and outer surfaces. Peeling is likely to occur. For the above reasons, it is desirable that the film thickness be 100 μm to 3 mm after remelting.

FIG.2 (b) is sectional drawing which shows another one form of the film of the water-cooled steel pipe structure formed by this invention. First, a lower layer film 9 made only of a Ni-based self-fluxing alloy is formed on the surface layer of the substrate 6, and the surface is coated with a film having the same form as the film shown in FIG.
A lower layer film has a role which improves the adhesiveness of a base material and the film of this invention more. The lower layer coating is more preferable when forming a coating on the surface with a characteristic that emphasizes corrosion resistance, that is, a coating of a component in which a Ni-based self-fluxing alloy is blended by 30 to 90% by mass with a Ni-based alloy.
The thickness of the lower layer film may be thin, and is preferably about 10 μm to 1 mm. The thickness of the coating on the surface is desirably 100 μm to 3 mm in the state after remelting in the same manner as in the case of (a) together with the lower layer coating.

Hereinafter, the present invention will be described more specifically with reference to examples.
The results of evaluating the properties of the coating of the present invention in comparison with other coatings will be described with reference to Tables 1 and 2.
As the coating material of the present invention, a Ni-based self-fluxing alloy SFNi4 mixed with 40% by mass of Ni-based alloy Inconel (registered trademark) 625 is sprayed on a normal steel base material by powder gas spraying, and then remelted. What was given was used. As comparative materials, a Ni self-fluxing alloy is obtained by gas spraying a single body of SFNi4 and remelting, a plasma sprayed product of Ni-Cr (50% / 50%), a high-speed gas sprayed product of CrC / NiCr, and Inconel (Registered trademark) 625 weld overlay was used.

Table 1 shows the results of comparative evaluation of high-temperature corrosion resistance by the corrosive ash immersion test method. In the corrosive ash immersion test, a test piece is immersed in dust collection dust containing 1% of Cl, and after sealing, heated to a temperature of 400 ° C., applied with a compressive force of 4 MPa, and maintained for 300 hours. The amount of erosion was measured.
The erosion ratio represents a ratio in which the amount of erosion of the boiler molten steel pipe SB410 is 100%.
As a result of the test, the coating of the present invention and Inconel (registered trademark) 625 showed a good corrosion resistance of 1/25 to 1/100 of the boiler steel pipe alone.

Table 2 shows the results of comparative evaluation of wear resistance by erosion wear test. In the erosion abrasion test, a steel grid of HV470 was projected from the compressed air nozzle at a speed of 90 m / sec onto the surface of the test piece. The distance between the nozzle and the test piece surface center point is 30 mm, and the projection angle is 45 degrees.
The wear rate was determined by calculating the wear weight by reducing the coating weight of the test piece after projecting for a certain period of time and dividing by the weight of the steel grid projected during the test time.
As a result of the test, the coating of the present invention and the self-fluxing alloy single coating showed good wear resistance of 1/40 to 1/100 of the wear amount of the steel pipe for boiler.
From the above evaluation results, it was found that the coating film of the present invention has the best performance in both corrosion resistance and wear resistance.

  In the lower hood 3, which is a water-cooled steel pipe structure exposed to an atmosphere of high temperature corrosion, erosion wear, and dew point corrosion in the exhaust gas treatment facility in the converter of the steelmaking factory shown in FIG. Of the water-cooled steel pipe structure 10 was coated on the inner surface which is the atmosphere side. The coating was thermally sprayed with 40% by mass of Ni-based alloy Inconel 625 mixed with Ni-based self-fluxing alloy SFNi4 and subjected to remelting treatment at a temperature of 1000 to 1100 ° C. The film thickness is 2 to 3 mm.

When the lower hood coated with this coating was used in actual operation of the converter for one year, the maximum reduction in film thickness was 0.2 mm, and there were no problems such as troubles related to operation and equipment management. there were.
In the case of the lower hood in this embodiment, conventionally, when only the boiler steel pipe SB410 as the base material is used, the maximum thickness reduction of about 2 mm has occurred in six months mainly due to high temperature corrosion. Therefore, a significant life improvement effect of about 10 times was confirmed by the coating of the present invention.

  As described above, by applying the water-cooled steel pipe structure of the present invention to, for example, converter exhaust gas treatment equipment of a steelmaking factory, the durability of the equipment against the atmosphere of high temperature corrosion, erosion wear, and dew point corrosion is greatly increased. As a result, the frequency of repairs when equipment is shut down is reduced compared to conventional systems, the operation rate is improved, and repair costs are greatly reduced, contributing to stabilization of operations and cost reduction. .

It is the conceptual diagram which showed the waste gas treatment equipment in the converter of the steelmaking factory concerning this invention. It is sectional drawing which showed 1 form (a) and the other form (b) of the film of the water-cooled steel pipe structure formed by this invention. It is sectional drawing which showed the form of the film of the water-cooled steel pipe structure of the converter exhaust gas processing equipment concerning this invention.

Explanation of symbols

1: Converter 2: Skirt 3: Lower hood 4: Upper hood 5: Dust collection duct 6: Base material 7: Ni-based self-fluxing alloy 8: Ni-based alloy 9: Lower layer coating 10: Water-cooled steel pipe structure base material 11: Coating

Claims (14)

By mass
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
In the Ni-based self-fluxing alloy which is the remaining Ni alloy,
Cr = 20-23%, Mo = 8-10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A material containing 10 to 90% by mass of the remaining Ni and an inevitable impurity Ni-based alloy is used as a thermal spray material, and the thermal spray material is sprayed on a base material and has a film formed by remelting treatment. A method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance. The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
2. The method for producing a water-cooled steel pipe structure excellent in corrosion resistance and wear resistance according to claim 1, wherein the alloy is composed of the balance Ni and inevitable impurities. The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
2. The method for producing a water-cooled steel pipe structure excellent in corrosion resistance and wear resistance according to claim 1, wherein the alloy is composed of the balance Ni and inevitable impurities. By mass
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
The Ni-based self-fluxing alloy, which is the remaining Ni alloy, is sprayed as a lower layer coating on the base material, and the Ni-based self-fluxing alloy is mass-coated on the surface of the coating.
Cr = 20-23%, Mo = 8-10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A material in which the alloy composed of the balance Ni and inevitable impurities is blended in an amount of 10 to 90% is used as a thermal spray material for the upper coating, and this thermal spray material is sprayed to form one or more layers and remelted. A method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance, comprising a formed coating. The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
5. The method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance according to claim 4, wherein the alloy is composed of the balance Ni and inevitable impurities. The Ni-based alloy blended in the self-fluxing alloy is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
5. The method for producing a water-cooled steel pipe structure having excellent corrosion resistance and wear resistance according to claim 4, wherein the alloy is composed of the balance Ni and inevitable impurities. Ni-based self-fluxing alloy further in mass,
Fe = 5% or less, Co = 1% or less,
The method for producing a water-cooled steel pipe structure excellent in corrosion resistance and wear resistance according to claim 1 or 4, characterized by containing one or more of Mo = 4% or less and Cu = 4% or less. By mass
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
In a Ni-based self-fluxing alloy that is an alloy of the balance Ni, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A water-cooled steel pipe structure excellent in corrosion resistance and wear resistance, characterized by having a coating containing 10 to 90% of a Ni-based alloy consisting of the balance Ni and inevitable impurities dispersed in mass. The Ni-based alloy dispersed and contained in the self-fluxing alloy is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance according to claim 8, wherein the water-cooled steel pipe structure is an alloy composed of the remaining Ni and inevitable impurities. The Ni-based alloy dispersed and contained in the self-fluxing alloy is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance according to claim 8, wherein the water-cooled steel pipe structure is an alloy composed of the remaining Ni and inevitable impurities. By mass
Cr = 10 to 20%, B = 2 to 4.5%,
Si = 2-5%, C = 0.4-1.1%,
In the lower layer coating of the Ni-based self-fluxing alloy that is the remaining Ni alloy, and in the self-fluxing alloy, Cr = 20 to 23%, Mo = 8 to 10%,
Fe = 2-7%, (Nb + Ta) = 1-4%,
A water-cooled steel pipe structure excellent in corrosion resistance and wear resistance, comprising an upper layer film containing 10 to 90% of a Ni-based alloy composed of the balance Ni and inevitable impurities dispersed therein. The Ni-based alloy dispersed and contained in the self-fluxing alloy as the upper layer coating is, by mass,
Cr = 20-23%, Mo = 8-10%,
Fe = 2 to 7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance according to claim 11, wherein the water-cooled steel pipe structure is excellent in corrosion resistance and wear resistance. The Ni-based alloy dispersed and contained in the self-fluxing alloy as the upper layer coating is, by mass,
Cr = 14-17%, Mo = 15-17%,
W = 3-5%, Fe = 4-7%,
The water-cooled steel pipe structure having excellent corrosion resistance and wear resistance according to claim 11, wherein the water-cooled steel pipe structure is excellent in corrosion resistance and wear resistance. Ni-based self-fluxing alloy further in mass,
Fe = 5% or less, Co = 1% or less,
The water-cooled steel pipe structure excellent in corrosion resistance and wear resistance according to claim 8 or 11, characterized by containing one or more of Mo = 4% or less and Cu = 4% or less.

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