CN111136405B

CN111136405B - Preparation method of nuclear power high-temperature nickel-based alloy composite welding wire and product thereof

Info

Publication number: CN111136405B
Application number: CN202010053849.0A
Authority: CN
Inventors: 陈静青; 莫涛; 张鹏举; 吴俣; 白文倩; 陈辉
Original assignee: Southwest Jiaotong University
Current assignee: Southwest Jiaotong University
Priority date: 2020-01-17
Filing date: 2020-01-17
Publication date: 2021-02-23
Anticipated expiration: 2040-01-17
Also published as: CN111136405A

Abstract

The invention discloses a preparation method of a nuclear power high-temperature nickel-based alloy composite welding wire and a product thereof, belonging to the technical field of welding and comprising the following steps: cleaning the surface of the high-temperature nickel-based alloy welding wire, and then sequentially carrying out mechanical grinding, polishing, alkali washing oil removal and electrolytic polishing treatment to prepare a welding wire I; electroplating a nickel layer on the surface of the welding wire I to prepare a welding wire II; electroplating a TiC coating on the nickel layer of the welding wire II to obtain a welding wire III; electroplating a nickel layer on the TiC plating layer of the welding wire III to prepare the nuclear power high-temperature nickel-based alloy composite welding wire; the nuclear power high-temperature nickel-based alloy composite welding wire prepared by the invention is low in cost and high in DDC crack resistance.

Description

Preparation method of nuclear power high-temperature nickel-based alloy composite welding wire and product thereof

Technical Field

The invention belongs to the technical field of welding, and particularly relates to a preparation method of a nuclear power high-temperature nickel-based alloy composite welding wire and a product thereof.

Background

The nickel-based high-temperature alloy Inconel690 is a key structural material of a pressure vessel, a heat dissipation evaporator and the like of nuclear power station core equipment, and has the characteristics of excellent high-temperature performance, corrosion resistance, oxidation resistance and the like.

The DDC has many factors, such as an alloy system, precipitated carbide, intercrystalline elements, the tortuosity of grain boundaries, grain boundary slippage, grain size, segregated impurities, the relationship between the grain boundaries and external stress and the like, and through the current literature and test conclusion, the grain boundary tortuosity of a nickel-based welding seam is increased, the grain size is reduced, and the DDC sensitivity can be obviously reduced. And through evaluating the DDC crack sensitivity of the welding lines with different grain sizes by a Gleeble technology-based uniaxial tensile test (STF test), the method for refining the grains is proved to improve the DDC resistance.

To improve the DDC crack sensitivity of high temperature nickel base alloy welds, a new brand weld material FM-52MSS is currently developed by U.S. Inconel corporation. The grade welding wire forms a large amount of second phase particles to pin solidification crystal boundaries during solidification by introducing 2% of Nb and 4% of Mo, forms a zigzag crystal boundary morphology and refines crystal grains.

However, the grade welding wire is expensive and is not widely applied to domestic nuclear power construction, in addition, the FM-52MSS welding material also has other problems, the fluidity of molten metal is deteriorated due to the increased alloying, the forming quality of a welding seam is influenced, the component segregation is aggravated during solidification, and another thermal crack, namely the solidification crack, is easily caused due to the large heat input. Aiming at the problems existing in the welding of the nuclear power nickel-based alloy at present, a novel welding wire needs to be developed urgently, the quality and the stability of a welding line are improved, a domestic welding wire is researched and developed, and the manufacturing cost of nuclear power is reduced.

Disclosure of Invention

Aiming at the problems, the invention aims to provide a preparation method of a nuclear power high-temperature nickel-based alloy composite welding wire and a product thereof.

In order to achieve the purpose, the invention adopts the technical scheme that:

a preparation method of a nuclear power high-temperature nickel-based alloy composite welding wire comprises the following steps:

(1) pretreatment: cleaning the surface of the high-temperature nickel-based alloy welding wire, and then sequentially carrying out mechanical grinding, polishing, alkali washing oil removal and electrolytic polishing treatment to prepare a welding wire I;

(2) nickel plating: electroplating a nickel layer on the surface of the welding wire I to prepare a welding wire II;

(3) and (3) TiC plating: electroplating a TiC coating on the nickel layer of the welding wire II to obtain a welding wire III;

(4) nickel plating: and electroplating a nickel layer on the TiC plating layer of the welding wire III to prepare the nuclear power high-temperature nickel-based alloy composite welding wire.

The high temperature nickel base alloy welding wire can be selected from imported welding wires, and the types are as follows: FM-52/FM-52M, and corresponding domestic high temperature nickel base alloy welding wire, such as HGH3044 nickel base high temperature alloy welding wire.

Further, the thickness of the nickel layer in the step (2) is 2-6 μm, the thickness of the TiC plating layer in the step (3) is 50-150 μm, and the thickness of the nickel layer in the step (4) is 2-10 μm.

Further, in the step (1), the alkaline solution in the alkaline cleaning oil comprises the following components in percentage by mass and volume: 15-25 g/L of sodium hydroxide, 25-35 g/L of trisodium phosphate, 25-35 g/L of sodium silicate and the balance of water.

Further, in the step (1), the temperature of alkali washing oil removal is 45-55 ℃, and the time is 6-15 min. The alkaline washing liquid removes oil stains or impurities on the surface of the high-temperature nickel-based alloy welding wire, the parameters are in an optimal parameter range, specific parameters can be adaptively adjusted according to specific conditions of the cleaned high-temperature nickel-based alloy welding wire, and the cleaned high-temperature nickel-based alloy welding wire is obtained.

Further, in the step (1), the electrolyte in the electrolytic polishing treatment comprises acetic acid and perchloric acid, and the mass ratio of the acetic acid to the perchloric acid is 3-5: 1.

Further, in the step (1), the electrolytic voltage in the electrolytic polishing treatment is 26-30V, and the electrifying time is 4-10 s. And (3) removing fine burrs on the surface of the workpiece and increasing the brightness by electrolytic polishing, wherein the parameters are in an optimal parameter range, the specific parameters can be adaptively adjusted according to the specific conditions of the high-temperature nickel-based alloy welding wire subjected to electrolytic polishing treatment, and the electrolytic polishing treatment is clean.

The surface of the material is mechanically ground and polished, washed with alkali to remove oil, and the surface is activated by electrolytic polishing to pretreat the composite electroplating. The welding wire is fed through a wire feeding mechanism, so that certain requirements are imposed on the bonding strength of the composite coating, the surface needs to be cleaned, crystal lattices on the surface are exposed, and the bonding strength of the coating is increased.

Further, the electroplating solution used in the electroplating process in the step (2) and the step (4) is a watt-type electroplating solution, and the watt-type electroplating solution comprises nickel sulfate hexahydrate, nickel chloride hexahydrate and boric acid. The watt type electroplating solution generally refers to a nickel plating solution containing nickel sulfate, nickel chloride and boric acid, a brightening agent is not added, the formula is common in a nickel plating process, and the specific formula can be adjusted adaptively or commercially available electroplating solutions can be purchased according to the prior art. For example, the formulation of the Watt-type plating solution is 400g/LNiSO₄，45g/LNiCl₂，50g/L H₃BO₃And the balance being water.

Further, in the step (3), the TiC electroplating solution comprises the following components in percentage by mass: TiC 20-40 g/L, NiSO₄400 g/L，NiCl₂45 g/L，H₃BO₃50 g/L, and the balance of water; the grain diameter of TiC is 3-10 μm.

When the size of TiC particles is too small, such as nano-scale, due to the fact that the arc temperature is too high during welding, titanium carbide particles are melted, the content of titanium in a matrix is increased, a brittle slag inclusion phase is formed, and the strength and the plasticity of the high-temperature nickel-based alloy are reduced. When the particle size is too large, the composite electroplating difficulty is improved, and the effect of the dispersed fine second phase pinning solidification crystal boundary is reduced, so that the crystal boundary tortuosity and the high-temperature strength of the high-temperature nickel-based alloy are reduced. The invention selects 3-10 μm TiC particles, which can not only avoid excessive dissolution of TiC particles, but also effectively ensure the crystal boundary pinning effect of TiC, refine the crystal grains of the high-temperature alloy, improve the tortuosity of the crystal boundary and ensure the high-temperature plasticity of the high-temperature alloy.

Further, the electroplating process parameter of the step (3) is 2-4A/dm of current density²The electroplating time is 0.5-3 h, the electroplating temperature is 40-50 ℃, and the stirring speed is 200-400 r/min. The above parameters may be adaptively adjusted within this range based on the specific conditions of the plated TiC process and the high temperature nickel-based alloy wire.

Further, the process parameter of the electro-nickelling in the step (2) and the step (4) is 3A/dm of current density²The electroplating time is 10min, the electroplating temperature is 45 ℃, the stirring speed is 300r/min, and the specific parameters can be adaptively adjusted based on the nickel electroplating process.

Further, the volume fraction of TiC added into the nuclear power high-temperature nickel-based alloy composite welding wire is between 0.5 and 1 percent.

The dispersed TiC particles are introduced into the high-temperature alloy matrix, so that the DDC sensitivity of the high-temperature alloy can be effectively reduced, and the high-temperature strength is improved. However, in the prior art, Ti and C are directly added into a high-temperature nickel-based alloy welding wire, excessive Ti can be combined with O to cause slag inclusion defects, and excessive C can form Cr with Cr at grain boundaries₂₃C₆And the phase is separated out, so that intergranular chromium is poor, and the intergranular corrosion resistance of the high-temperature nickel-based alloy is reduced.

The key point of the technology of the invention is to analyze the rule of the influence of the composite electroplating process parameters on the thickness of the Ni-TiC-Ni coating, the density of the strengthening phase and the binding force of the coating, and establish the regulation and control mechanism of the TiC strengthening phase granularity and the volume fraction on the welding seam microstructure.

The scheme of the invention is to electroplate a Ni-TiC-Ni composite coating on the surface of the welding wire, because the melting point of TiC is very high, TiC particles can be directly and uniformly introduced into a welding line through composite electroplating, the effects of refining grains and pinning grain boundaries can be exerted, and the element contents of C and Ti can not be improved. Therefore, TiC particles are introduced into the Ni-TiC-Ni coating prepared by composite electroplating during welding, and DDC crack sensitivity can be remarkably reduced.

The invention has the beneficial effects that:

1) the TiC particles with the particle size of 3-10 mu m are selected, so that excessive dissolution of the TiC particles can be avoided, the grain boundary pinning effect of the TiC can be effectively ensured, the crystal grains of the high-temperature alloy are refined, the grain boundary tortuosity is improved, and the high-temperature plasticity is ensured;

2) according to the scheme, a layer of Ni-TiC-Ni composite coating is electroplated on the surface of the welding wire, and combined with the control of composite electroplating process parameters, TiC particles can be directly and uniformly introduced into a welding line through composite electroplating, so that the effects of refining grains and pinning grain boundaries can be exerted, the element contents of C and Ti can not be improved, the DDC crack sensitivity can be remarkably reduced, and the cost is lower.

Drawings

FIG. 1 is a schematic view of composite plating according to the present invention;

FIG. 2 is the weld grain morphology of comparative example 1;

FIG. 3 is the weld grain morphology of comparative example 1;

FIG. 4 is the weld grain morphology of example 1;

FIG. 5 is the weld grain morphology of example 1;

FIG. 6 is the weld grain morphology of comparative example 2;

FIG. 7 is the weld grain morphology of comparative example 2;

FIG. 8 is the weld grain morphology of example 2;

FIG. 9 is the weld grain morphology of example 2;

FIG. 10 is a plot of different particle volume fractions versus grain size;

FIG. 11 is a flow chart of electroplating.

Detailed Description

In order to further illustrate the technical effects of the present invention, the present invention is specifically described below by way of examples.

Example 1

(1) Pretreatment: the surface of the high-temperature nickel-based alloy welding wire is cleaned, the surface of the high-temperature nickel-based alloy welding wire is ground by using sand paper and then polished, and then the high-temperature nickel-based alloy welding wire is cleaned in a mixed solution of sodium hydroxide (20g/L), trisodium phosphate (30g/L) and sodium silicate (30g/L) at 50 ℃ for 10 min. Finally, performing electrolytic polishing in a mixed acid of 80% acetic acid and 20% perchloric acid, wherein the electrolytic voltage is 27V, and electrifying for 7s to prepare a welding wire I;

(2) nickel plating: preparing watt-type electrolyte, wherein the electroplating solution comprises nickel sulfate hexahydrate, nickel chloride hexahydrate and boric acid, electroplating a nickel layer on the surface of the welding wire I to prepare a welding wire II, and the electroplating process parameter is 3A/dm of current density²Electroplating time is 10min, electroplating temperature is 45 ℃, and stirring speed is 300 r/min;

(3) and (3) TiC plating: preparing TiC electroplating solution, wherein the TiC electroplating solution comprises the following components in percentage by mass and volume: TiC 30g/L, NiSO₄400 g/L，NiCl₂45 g/L，H₃BO₃50 g/L, and the balance of water; the grain diameter of TiC is 3-10 mu m, a TiC coating is electroplated on the nickel layer of the welding wire II to prepare a welding wire III, and the electroplating technological parameter is current density 3A/dm²Electroplating time is 0.5h, electroplating temperature is 45 ℃, and stirring speed is 300 r/min;

(4) nickel plating: preparing a Watt-type electrolyte, the electroplating solution comprising 400g/LNiSO₄，45g/LNiCl₂，50g/L H₃BO₃And the balance of water, electroplating a nickel layer on the TiC plating layer of the welding wire III to prepare the nuclear power high-temperature nickel-based alloy composite welding wire, wherein the electroplating process parameter is current density 3A/dm²The electroplating time is 10min, the electroplating temperature is 45 ℃, and the stirring speed is 300 r/min.

The volume fraction of TiC in the nuclear power high-temperature nickel-based alloy composite welding wire is 0.7%.

And (4) performing TIG surfacing on the nuclear power high-temperature nickel-based alloy composite welding wire prepared in the step (4) and the welding wire without the composite coating, wherein the welding process parameters are shown in Table 1.

TABLE 1 welding Process parameters

The TiC particles are introduced into the nickel-based alloy welding seam to play two main roles, namely, the TiC particles serve as nucleation particles to reduce the grain size of the welding seam when the welding seam is solidified. Secondly, when the TiC particles are distributed on the grain boundary, the grain boundary can be pinned, and the grain boundary slippage can be inhibited. When TiC particles are introduced, coarse columnar crystals in the welding seam are obviously reduced, the crystal grains are obviously refined, meanwhile, the tortuosity of the welding seam crystal boundary is obviously increased, and the DDC resistance of the nickel-based alloy can be obviously improved.

Comparative example 1

The method for preparing the welding wire in the comparative example 1 does not include the step of TiC plating in the step (3), the rest steps are the same as those in the example 1, and the welding process is the same as that in the example 1.

Referring to fig. 2-5, the welding wire of comparative example 1 and comparative example 1, when the volume fraction of TiC particles is 0.70%, the grain size is reduced by about 33.64%.

Example 2

(2) nickel plating: preparing a Watt-type electrolyte, the electroplating solution comprising 400g/LNiSO₄，45g/LNiCl₂，50g/L H₃BO₃And the balance of water, electroplating a nickel layer on the surface of the welding wire I to prepare a welding wire II, wherein the electroplating process parameter is current density 3A/dm²Plating time of 10min, plating temperature of 45 ℃ and stirring speed of 300rmin；

(3) And (3) TiC plating: preparing TiC electroplating solution, wherein the TiC electroplating solution comprises the following components in percentage by mass and volume: TiC 40g/L, NiSO₄400 g/L，NiCl₂45 g/L，H₃BO₃50 g/L, and the balance of water; the grain diameter of TiC is 3-10 mu m, a TiC coating is electroplated on the nickel layer of the welding wire II to prepare a welding wire III, and the electroplating technological parameter is current density 3A/dm²The electroplating time is 2h, the electroplating temperature is 45 ℃, and the stirring speed is 300 r/min;

(4) nickel plating: preparing watt-type electrolyte, wherein the electroplating solution comprises nickel sulfate hexahydrate, nickel chloride hexahydrate and boric acid, electroplating a nickel layer on the TiC plating layer of the welding wire III to prepare the nuclear power high-temperature nickel-based alloy composite welding wire, and the electroplating technological parameter is current density 3A/dm²The electroplating time is 10min, the electroplating temperature is 45 ℃, and the stirring speed is 300 r/min.

The volume fraction of TiC in the nuclear power high-temperature nickel-based alloy composite welding wire is 0.99%.

TABLE 1 welding Process parameters

Comparative example 2

The method for preparing the welding wire in the comparative example 2 does not have the step of TiC plating in the step (3), the rest steps are consistent with the step of example 2, and the welding process is consistent with the step of example 2.

Referring to fig. 6-9, the welding wires of comparative example 2 and comparative example 2, when the volume fraction of TiC particles in the weld is increased to 0.99%, the grains of the weld are further refined, and the grain size is reduced by about 50.22% as compared with 0, and the degree of tortuosity is increased. As shown in fig. 10, as the TiC particle content increases, the weld grain size continues to decrease.

When the volume fraction of TiC introduced into the welding wire is lower than 1%, the microstructure is better improved. When the volume fraction of TiC is continuously increased, the welding forming quality is reduced, and the welding quality is reduced due to difficulty in slag removal in the welding process.

Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting, and although the technical solutions of the present invention are described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. The preparation method of the nuclear power high-temperature nickel-based alloy composite welding wire is characterized by comprising the following steps of:

2. The preparation method of claim 1, wherein the thickness of the nickel layer in the step (2) is 2-6 μm, the thickness of the TiC plating layer in the step (3) is 50-150 μm, and the thickness of the nickel layer in the step (4) is 2-10 μm.

3. The preparation method according to claim 1, wherein in the step (1), the alkaline washing solution in the alkaline washing oil comprises the following components in mass-to-volume ratio: 15-25 g/L of sodium hydroxide, 25-35 g/L of trisodium phosphate, 25-35 g/L of sodium silicate and the balance of water.

4. The preparation method according to claim 1, wherein in the step (1), the temperature of the alkali washing oil removal is 45-55 ℃ and the time is 6-15 min.

5. The preparation method according to claim 1, wherein in the step (1), the electrolyte in the electrolytic polishing treatment comprises acetic acid and perchloric acid, and the mass ratio of the acetic acid to the perchloric acid is 3-5: 1.

6. The method according to claim 1, wherein in the step (1), the electrolytic voltage in the electrolytic polishing treatment is 26 to 30V, and the energization time is 4 to 10 s.

7. The production method according to claim 1, wherein the plating solution used in the plating process in the step (2) and the step (4) is a watt-type plating solution comprising nickel sulfate hexahydrate, nickel chloride hexahydrate, and boric acid.

8. The preparation method according to claim 1, wherein in the step (3), the TiC electroplating solution comprises, by mass and volume: TiC 20-40 g/L, NiSO₄ 400 g/L，NiCl₂ 45 g/L，H₃BO₃50 g/L, and the balance of water; the grain diameter of TiC is 3-10 μm.

9. The method according to claim 1, wherein the electroplating process parameter in step (3) is a current density of 2-4A/dm²The electroplating time is 0.5-3 h, the electroplating temperature is 40-50 ℃, and the stirring speed is 200-400 r/min.

10. The nuclear power high-temperature nickel-based alloy composite welding wire prepared by the preparation method of any one of claims 1 to 9, wherein the volume fraction of TiC in the welding wire is 0.5 to 1 percent.