CN113584381B - High-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy and its electroslag remelting method - Google Patents

Abstract

The invention relates to the field of metallurgy, in particular to a high-strength copper-containing Ni-Fe-Cr-based age hardening type corrosion-resistant alloy and an electroslag remelting method thereof, wherein when the environment temperature of the prepared high-strength copper-containing Ni-Fe-Cr-based age hardening type corrosion-resistant alloy is-60 ℃, the low-temperature impact power is more than or equal to 61J, the room-temperature tensile strength is more than or equal to 1030Mpa, the yield strength is more than or equal to 860Mpa, the elongation is more than or equal to 19%, the reduction of area is more than or equal to 25%, the Rockwell hardness is 30-40 HRC, the grain size is more than or equal to 2.5 grade, the structure is uniform and compact, sigma phases, LAVES and other topologically closely-arranged brittle phases cannot be separated out in the structure, the later-stage thermal deformation is facilitated, cracks are not easy to generate in the thermal processing process of the alloy, the yield of the alloy in the thermal processing process is greatly improved, especially for large-size bar products with the diameter of more than 300mm, the segregation degree of chemical components of an electroslag ingot is well controlled, and the forging performance is excellent.

Description

High-strength copper-containing Ni-Fe-Cr based age-hardening corrosion-resistant alloy and its electroslag remelting method

technical field

The invention relates to the field of metallurgy, in particular to a high-strength copper-containing Ni-Fe-Cr based age-hardening corrosion-resistant alloy and an electroslag remelting method thereof.

Background technique

Nickel-based alloys such as MonelK-500, Inconel 690, and UNS718 are the mainstream manufacturing materials for equipment and components currently used in various corrosive environments.

The above-mentioned nickel-based alloy has excellent performance, but because of its high nickel content, the manufacturing cost is greatly affected by the market price of raw material nickel. Especially starting from 2020, the price of raw materials fluctuates violently. In 2021, the price of nickel will increase by more than 30%, which has a great impact on the cost control of alloy production enterprises. In order to control the manufacturing cost of nickel-based alloys with excellent performance and improve the ability of enterprises to resist market risks, some special alloy manufacturing enterprises in developed countries such as: Baker Hughes, Special Metals and other companies have begun to develop corrosion-resistant alloys with low nickel content for petroleum In various corrosive environments, by adding cheaper alloy elements to replace part of nickel, the manufacturing cost of nickel-based alloys is greatly reduced, and the mechanical properties of nickel-based alloys manufactured in this way can be similar to those of UNS 718, which has a considerable market Application prospect.

The original design intention of the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy is to have a low nickel content (that is, the nickel content is 46-49%), but it needs to maintain its good material mechanical properties , only through the reasonable combination of alloying elements Nb, Cr, Mo, Cu and other alloying elements, it has excellent corrosion resistance and mechanical properties. At the same time, due to the low nickel content in the alloy, the forgeable range in the hot working range is very narrow. In order to improve the hot working performance of the alloy and ensure its actual producibility, it is necessary to add a small amount of microalloying elements to improve its hot workability. After forging, solid solution and aging treatment, the alloy can obtain excellent comprehensive mechanical properties close to those of UNS 718 alloy.

The standard compositions of the commonly used corrosion-resistant alloys UNS718 and Inconel690 are shown in Table 1. Among them, the mechanical properties of UNS718, the lowest tensile strength R _m is 820 MPa, and the highest can reach about 1400 MPa; while the lowest tensile strength of Inconel 690 alloy is R _m ≥ 580 MPa , up to 700MPa.

Table 1

At present, research on high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloys to replace traditional UNS718, Inconel690, and MonelK-500 materials has become a new orientation for the energy and petroleum industry markets.

However, due to the addition of a large amount of Nb and Cu to the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy, Nb and Cu elements are strong segregation elements in the electroslag remelting process, which is easy to cause macro segregation. Furthermore, in the later stage of thermal processing, cracking occurs, and the use of ordinary electroslag remelting process is prone to serious chemical composition segregation, which in turn leads to uneven organization, loose organization, and sigma phase, LAVES and other top densely packed brittle phases are easily precipitated in the organization. These are all factors that are unfavorable to the thermal deformation in the later stage. Cracks are easy to occur in the later thermal processing process, which seriously reduces the yield in the thermal processing process, especially for large-scale bar products with a diameter > 300mm. If the electroslag process cannot be controlled The degree of segregation of the chemical composition of the electroslag ingot and the macro-segregation produced by it cannot be significantly improved by subsequent processes such as diffusion annealing, resulting in poor forging performance.

Contents of the invention

The purpose of the present invention is to address the shortcomings of the prior art, to provide a high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy and its electroslag remelting method. The prepared alloy has a uniform and compact structure with a No sigma phase, LAVES and other top densely packed brittle phases will be precipitated in the alloy, which is beneficial to the later thermal deformation, and it is not easy to produce cracks during the thermal processing of the alloy, which greatly improves the yield of the alloy during thermal processing, especially for the diameter For large-scale bar products >300mm, the chemical composition segregation degree of the electroslag ingot has been well controlled, and the forging performance is excellent.

The object of the present invention is to adopt following scheme to realize: a kind of high-strength copper-containing Ni-Fe-Cr base age-hardening type corrosion-resistant alloy, the weight percent of each component of this alloy is: C≤0.03%, Si≤0.3% , Mn≤0.5%, 18%≤Cr≤23%, 46%≤Ni≤49%, 2.8%≤Mo≤4%, 2.8%≤Nb≤4%, 1.5%≤Cu≤3%, 1%≤Ti ≤3%, 0.15%≤Al≤0.5%, B≤0.005%, Zr≤0.15%, and the balance is Fe.

Preferably, the weight percentage of each component of the alloy is: 0.012%≤C≤0.023%, 0.182%≤Si≤0.232%, 0.472%≤Mn≤0.496%, 21.71%≤Cr≤21.98%, 47.11%≤Ni≤ 48.46%, 3.41%≤Mo≤3.75%, 3.06%≤Nb≤3.97%, 1.88%≤Cu≤2.06%, 1.62%≤Ti≤1.98%, 0.208%≤Al≤0.424%, 0.0036%≤B≤0.0041% , 0.0107%≤Zr≤0.15%, the balance is Fe.

C, Si, and Mn in the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy are: C+Si+Mn<1%.

An electroslag remelting method for high-strength copper-containing Ni-Fe-Cr-based age-hardening type corrosion-resistant alloys has the following steps:

1) Vacuum melting and casting the alloy raw material into a round bar, and after finishing, a remelting electrode rod for high-strength copper-containing Ni-Fe-Cr-based age-hardening type corrosion-resistant alloy electroslag remelting is obtained;

The round bar first needs to be surface sanded, and after the scale is removed, finishing is carried out.

The weight percent of each component of the alloy raw material is: C≤0.03%, Si≤0.3%, Mn≤0.6%, 17%≤Cr≤22%, 46%≤Ni≤49%, 2.8%≤Mo≤5% , 2.8%≤Nb≤5%, 1.5%≤Cu≤3%, 0.5%≤Ti≤3%, 0.15%≤Al≤0.7%, B≤0.005%, Zr≤0.2%, the balance is Fe;

Preferably, the weight percent of each component of the alloy raw material is: C≤0.03%, Si≤0.3%, Mn≤0.46%, 18%≤Cr≤23%, 47%≤Ni≤49%, 3%≤Mo ≤4%, 3%≤Nb≤4%, 1.5%≤Cu≤3%, 1%≤Ti≤3%, 0.3%≤Al≤0.5%, B≤0.005%, 0.05%≤Zr≤0.15%, remainder The amount is Fe.

The boron content in the remelted electrode rod is ≤0.004%, and the zirconium content is ≤0.12%.

2) Take the components of the slag material, mix well, bake at 800°C for not less than 3 hours, and arc to melt the slag;

The parts by weight of the components of the slag are: CaF ₂ : 65-75 parts; CaO: 8-15 parts; Al ₂ O ₃ : 10-18 parts; MgO: 5-11 parts;

Preferably, the components of the slag system are CaF ₂ : 65-75 parts by weight; CaO: 10-12 parts; Al ₂ O ₃ : 10-18 parts; MgO: 5-7 parts.

The remelting electrode rod is slowly inserted into the slag pool in the molten state, and the voltage, current and chemical material are adjusted according to the diameter of the remelting electrode rod after the arc is energized;

When the diameter of the remelted electrode rod is 80-150mm, the current is (3-4)±0.5kA and the voltage is (40-45)±5V; when the diameter is 151-400mm, the current is (7-14)± 0.5kA, the voltage is (45~60)±2V, that is, the current and voltage values during the remelting process are adjusted according to the diameter of the remelting electrode rod.

That is, the slag material of electroslag remelting is mixed evenly, heated in a box-type resistance furnace to a temperature not lower than 800°C, dried for not less than 3 hours, and used in a cast iron crucible or crystallizer to energize and start an arc with a graphite electrode rod Heat to molten state.

Through the basic oxides such as CaO and MgO in the slag material, the increase of harmful elements such as P and S is controlled, so that the P content in the obtained electroslag ingot does not exceed 30 ppm, and the S content does not exceed 15 ppm.

3) Cooling and demoulding after remelting to obtain electroslag ingots;

The content of P in the electroslag ingot is not more than 30ppm, and the content of S is not more than 15ppm.

Usually, the electroslag ingot is obtained by thermal feeding before the end of the remelting, and the electroslag ingot is placed in a crystallizer to cool and then demoulded, and the cooling time is ≥ 30 minutes.

The thermal feeding adopts the power decreasing method, and the starting current of feeding is the ending current of electroslag remelting.

4) The electroslag ingot is hot-processed and forged into a bar, and after solid solution and aging treatment, a high-strength copper-containing Ni-Fe-Cr based age-hardening corrosion-resistant alloy is obtained.

The high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy has low-temperature impact energy ≥ 61J at an ambient temperature of -60°C, room temperature tensile strength ≥ 1030Mpa, yield strength ≥ 860Mpa, and elongation ≥ 19%, reduction of area ≥ 25%, Rockwell hardness 30-40HRC, grain size ≥ 2.5.

The present invention includes the following beneficial effects: the Ni, Cr and Fe elements in the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy are the basic elements of the nickel-based alloy, so that the nickel-based corrosion-resistant alloy has austenitic body matrix and corrosion resistance.

At present, the Ni content in the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy system is usually 53%, and the high-strength copper-containing Ni-Fe-Cr-based age-hardenable corrosion-resistant alloy prepared by the present invention contains The Ni content is 46%≤Ni≤49%, less than 53%. Part of the nickel is replaced by Cu and Nb to ensure its mechanical properties and corrosion resistance. However, excessive Cu will reduce the thermoplasticity of the alloy and affect the hot workability. Therefore, when the corrosion-resistant alloy is prepared in the present invention, the Cu content in the alloy raw material is limited within the range of 1.5%≤Cu≤3%, so as to avoid the above problems.

Nb, Ti and Al are the main constituents of the strengthening precipitate phases γ' and γ" phases of precipitated hard alloys. If the addition amount is too large, the hot workability will be reduced, and if the addition amount is too low, the performance will be insufficient. The corrosion-resistant alloy prepared by the present invention When, the Nb content in the alloy raw material is limited in the range of 2.8%≤Nb≤5%.

Ti and Al are elements that are easy to segregate and burn. Due to the addition of too much Ti and Al during the electroslag remelting smelting process, the composition of the prepared electroslag ingot will be seriously segregated, which is not conducive to the later thermal processing and stability. Material performance, so when preparing the corrosion-resistant alloy in the present invention, the Ti content in the alloy raw material is 0.5%≤Ti≤3%, and the Al content is 0.15%≤Al≤0.7%.

Mo and Nb are solid solution strengthening elements for nickel-based alloys. Mo element is the main compounding element of M ₆ C, and excessive amount is easy to form grain boundary carbide coating film, topological close-packed phase, and reduces alloy toughness, and its content needs to be properly controlled, so when the present invention prepares corrosion-resistant alloys, the alloy The Mo content in the raw material is 2.8%≤Mo≤5%.

C, Si, and Mn elements can deoxidize and refine alloys, improve the fluidity of liquid metal, and improve the casting performance of metals, but these elements are easy to form TCP phases equal to LAVES, and are easy to segregate grain boundaries, resulting in a decrease in the grain boundary strength of the alloy. The weight percentages of the three elements in the alloy should meet the following conditions:

w(C)+w(Si)+w(Mn)＜1%

In the formula, w(C) is the weight percentage of C in the prepared alloy, w(Si) is the weight percentage of Si in the prepared alloy, and w(Mn) is the weight percentage of Mn in the prepared alloy .

The content of boron in the remelted electrode rod is less than or equal to 0.004%. In nickel-based corrosion-resistant alloys, the usual content of alloying element boron is only a few dozen ppm. Strong, easy to cause cracking along grain boundaries during forging.

The content of zirconium in the remelted electrode rod is less than or equal to 0.12%. Zirconium improves the morphology of alloy carbides and the hot cracking tendency of the alloy, and too much zirconium affects the toughness of the alloy.

When the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy with a nickel content of 46%≤Ni≤49% is prepared, if the slag according to the present invention is not used, the flaw detection after forging is unqualified, and internal cracks, Metallography shows that there is a lot of porosity, and the number of Nb-rich phases is obviously large; if the slag material according to the present invention is used for electroslag remelting production, after forging, the flaw detection is qualified, and the metallography shows that the structure is uniform and there is no harmful phase. The rate is higher.

The applicant has verified through experiments that the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy described in the present invention has low-temperature impact energy ≥ 61J and room temperature tensile strength ≥ 1030Mpa when the ambient temperature is -60°C , Yield strength ≥ 860Mpa, elongation ≥ 19%, reduction of area ≥ 25%, Rockwell hardness 30 ~ 40HRC, grain size ≥ 2.5.

The high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy described in the present invention is suitable for applications in the chemical, marine and energy industries that require economic cost, material strength, high temperature and corrosion resistance, and is especially suitable for making simultaneous It is a load-bearing member for the exploitation of deep-sea oil and gas environments containing high CO ₂ , H ₂ S , Cl- and elemental S.

Description of drawings

Fig. 1 is the metallographic diagram of the alloy prepared in embodiment 1 of the present invention;

Fig. 2 is the metallographic structure diagram of the alloy prepared by using other electroslag materials.

Detailed ways

As shown in Figures 1 to 2, a high-strength copper-containing Ni-Fe-Cr based age-hardening corrosion-resistant alloy, the weight percentage of each component of the alloy is: C≤0.03%, Si≤0.3%, Mn≤ 0.5%, 18%≤Cr≤23%, 46%≤Ni≤49%, 2.8%≤Mo≤4%, 2.8%≤Nb≤4%, 1.5%≤Cu≤3%, 1%≤Ti≤3% , 0.15%≤Al≤0.5%, B≤0.005%, Zr≤0.15%, and the balance is Fe.

Preferably, the weight percentage of each component of the alloy is: 0.012%≤C≤0.023%, 0.182%≤Si≤0.232%, 0.472%≤Mn≤0.496%, 21.71%≤Cr≤21.98%, 47.11%≤Ni≤ 48.46%, 3.41%≤Mo≤3.75%, 3.06%≤Nb≤3.97%, 1.88%≤Cu≤2.06%, 1.62%≤Ti≤1.98%, 0.208%≤Al≤0.424%, 0.0036%≤B≤0.0041% , 0.0107%≤Zr≤0.15%, the balance is Fe.

C, Si, and Mn in the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy are: C+Si+Mn<1%, that is, the three elements C, Si, and Mn are in the alloy The percentage by weight should meet the following conditions:

w(C)+w(Si)+w(Mn)＜1%

In the formula, w(C) is the weight percentage of C in the prepared alloy, w(Si) is the weight percentage of Si in the prepared alloy, and w(Mn) is the weight percentage of Mn in the prepared alloy .

The electroslag remelting method for preparing the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy has the following steps:

1) Vacuum melting and casting the alloy raw material into a round bar, and after finishing, a remelting electrode rod for high-strength copper-containing Ni-Fe-Cr-based age-hardening type corrosion-resistant alloy electroslag remelting is obtained;

The round bar first needs to be surface sanded, and after the scale is removed, finishing is carried out.

The weight percent of each component of the alloy raw material is: C≤0.03%, Si≤0.3%, Mn≤0.6%, 17%≤Cr≤22%, 46%≤Ni≤49%, 2.8%≤Mo≤5% , 2.8%≤Nb≤5%, 1.5%≤Cu≤3%, 0.5%≤Ti≤3%, 0.15%≤Al≤0.7%, B≤0.005%, Zr≤0.2%, the balance is Fe;

Preferably, the weight percent of each component of the alloy raw material is: C≤0.03%, Si≤0.3%, Mn≤0.46%, 18%≤Cr≤23%, 47%≤Ni≤49%, 3%≤Mo ≤4%, 3%≤Nb≤4%, 1.5%≤Cu≤3%, 1%≤Ti≤3%, 0.3%≤Al≤0.5%, B≤0.005%, 0.05%≤Zr≤0.15%, remainder The amount is Fe.

The boron content in the remelted electrode rod is ≤0.004%, and the zirconium content is ≤0.12%.

2) Take the components of the slag material, mix well, bake at 800°C for not less than 3 hours, and arc to melt the slag;

The parts by weight of the components of the slag are: CaF ₂ : 65-75 parts; CaO: 8-15 parts; Al ₂ O ₃ : 10-18 parts; MgO: 5-11 parts;

Preferably, the components of the slag system are CaF ₂ : 65-75 parts by weight; CaO: 10-12 parts; Al ₂ O ₃ : 10-18 parts; MgO: 5-7 parts.

The remelting electrode rod is slowly inserted into the slag pool in the molten state, and the voltage, current and chemical material are adjusted according to the diameter of the remelting electrode rod after the arc is energized;

When the diameter of the remelted electrode rod is 80-150mm, the current is (3-4)±0.5kA and the voltage is (40-45)±5V; when the diameter is 151-400mm, the current is (7-14)± 0.5kA, the voltage is (45~60)±2V, that is, the current and voltage values during the remelting process are adjusted according to the diameter of the remelting electrode rod.

That is, the slag material of electroslag remelting is mixed evenly, heated in a box-type resistance furnace to a temperature not lower than 800°C, dried for not less than 3 hours, and used in a cast iron crucible or crystallizer to energize and start an arc with a graphite electrode rod Heat to molten state.

Through the basic oxides such as CaO and MgO in the slag material, the increase of harmful elements such as P and S is controlled, so that the P content in the obtained electroslag ingot does not exceed 30 ppm, and the S content does not exceed 15 ppm.

3) Cooling and demoulding after remelting to obtain electroslag ingots;

The content of P in the electroslag ingot is not more than 30ppm, and the content of S is not more than 15ppm.

Usually, the electroslag ingot is obtained by thermal feeding before the end of the remelting, and the electroslag ingot is placed in a crystallizer to cool and then demoulded, and the cooling time is ≥ 30 minutes.

The thermal feeding adopts the power decreasing method, and the starting current of feeding is the ending current of electroslag remelting.

4) The electroslag ingot is hot-processed and forged into a bar, and after solid solution and aging treatment, a high-strength copper-containing Ni-Fe-Cr based age-hardening corrosion-resistant alloy is obtained.

The high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy has low-temperature impact energy ≥ 61J at an ambient temperature of -60°C, room temperature tensile strength ≥ 1030Mpa, yield strength ≥ 860Mpa, and elongation ≥ 19%, reduction of area ≥ 25%, Rockwell hardness 30-40HRC, grain size ≥ 2.5.

Do the following examples according to the above method, and prepare high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloys with different properties:

Example 1

a) Preparation of remelted electrode rod

Calculated on the basis of 60 kg of total alloy weight per furnace, the weight percentages of each component of the remelted electrode rod ingredients for preparing the high-strength copper-containing Ni-Fe-Cr-based age-hardening type corrosion-resistant alloy are as follows: Ni is 48%, and Cr is 22% %, Ti 2%, Al 0.5%, Mo 4%, Cu 2%, Mn 0.4%, Si 0.2%, Nb 3.6%, C 0.02%, B 0.004%, Zr 0.01 %, Fe is the balance, after vacuum induction melting, casting into a Ф100mm round rod, after the surface is sanded and finished, it is the remelting electrode rod used in electroslag remelting, the length of the remelting electrode rod is 95mm.

b) Electroslag remelting

①The slag is calculated according to the amount of 5kg per furnace, and the parts by weight of each component are as follows: 65 parts of _CaF2 , ₁₈ parts of _Al2O3 , 10 parts of CaO, and 7 parts of MgO. After drying at 800°C for 3 hours, the above-mentioned slag was heated to a molten state in a cast iron crucible through a graphite electrode rod.

② Slowly drop the prepared remelting electrode rod into the molten electroslag remelting slag material. After the arc is energized, adjust the remelting voltage to 45V±5V, and gradually adjust the current to (3~4)±0.5kA;

③The remelted electrode rod is slowly melted by resistance heat, and the melted remelted electrode rod droplet passes through the molten slag material layer to undergo a chemical reaction with the slag material to be purified, and recrystallized at the bottom of the crystallizer to obtain a Ф160mm electrode Slag ingot.

After testing, the harmful elements S<11ppm and P<12ppm in the electroslag ingot, the content of P and S are qualified.

c) Alloy performance test

The electroslag ingot is hot-forged into a rod, and after solid solution and aging treatment, the weight percentages of the components of the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy obtained are as follows: C is 0.023%, Si is 0.232%, Mn is 0.472%, Cr is 21.98%, Ni is 48.46%, Mo is 3.75%, Nb is 3.97%, Cu is 2.06%, Ti is 1.98%, Al is 0.424%, B is 0.0041%, Zr is 0.0107%, and the balance is Fe; when the ambient temperature is -60°C, the low-temperature impact energy is 64J, and the room temperature tensile strength is 1368MPa, the yield strength is 926MPa, the elongation is 26.5%, and the reduction of area is 28%, Rockwell hardness: 38HRC, grain size 4 grade.

Example 2

a) Preparation of remelted electrode rod

Calculated on the basis of 450kg of the total weight of each furnace alloy, the weight percentages of each component of the remelted electrode rod ingredients for preparing the high-strength copper-containing Ni-Fe-Cr-based age-hardening type corrosion-resistant alloy are as follows: Ni is 47%, and Cr is 22% %, Ti 1.5%, Al 0.3%, Mo 3.2%, Cu 1.5%, Mn 0.3%, Si 0.15%, Nb 3%, C 0.015%, B 0.003%, Zr 0.15 %, Fe is the balance, after vacuum induction melting, casting into a round rod of Ф260mm, after the surface is sanded and finished, it is the remelting electrode rod used in electroslag remelting, the length of the remelting electrode rod It is 1800mm.

b) Electroslag remelting

1. The slag is calculated as 25kg according to the amount per furnace, and the parts by weight of each component are as follows: 75 parts of CaF, ₁₀ parts of _Al2O3 , 10 parts of CaO, _and 5 parts of MgO. The slag material of electroslag remelting is mixed evenly, heated in a box-type resistance furnace to no less than 800°C and dried for no less than 3 hours, and the graphite electrode rod is used to energize the arc in the crystallizer and heated to a molten state, the crystallizer and the bottom plate All use water cooling.

②Slowly lower the prepared remelting electrode rod into the molten electroslag remelting slag material, and adjust the remelting voltage to 53V±2V and the current to (7～14)±0.5kA after the arc is energized;

③The remelted electrode rod is slowly melted by the resistance heat, and the molten remelted electrode rod droplet passes through the molten slag layer to react with the slag material to be purified, and recrystallized at the bottom of the crystallizer to obtain Φ320mm electroslag ingot. After testing, the contents of harmful elements sulfur and phosphorus in the prepared alloy are as follows: S=10ppm, P=18ppm; the contents of sulfur and phosphorus are qualified.

c) Alloy performance test

After the electroslag ingot is heat-treated by high-temperature uniform diffusion annealing, it is heated and forged into a rod, and after solid solution and aging treatment, the weight percentage of each component of the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy obtained As follows: C is 0.012%, Si is 0.182%, Mn is 0.496%, Cr is 21.71%, Ni is 47.11%, Mo is 3.41%, Nb is 3.06%, Cu is 1.88%, Ti is 1.62%, Al is 0.208 %, B is 0.0036%, Zr is 0.15%, and the balance is Fe; when the ambient temperature is -60°C, the low-temperature impact energy is 89J, and the room temperature tensile strength is 1135MPa, the yield strength is 885MPa, and the elongation is 28.5%, reduction of area 44%, Rockwell hardness: 38.5HRC, grain size 4.5.

The above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any changes made by those skilled in the art to the present invention fall within the protection scope of the present invention without departing from the spirit of the present invention.

Claims (7)

1. A high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy, characterized in that the weight percentage of each component of the alloy is: 0.012%≤C≤0.023%, 0.182%≤Si≤0.232% , 0.472%≤Mn≤0.496%, 21.71%≤Cr≤21.98%, 47.11%≤Ni≤48.46%, 3.41%≤Mo≤3.75%, 3.06%≤Nb≤3.97%, 1.88%≤Cu≤2.06%, 1.62 %≤Ti≤1.98%, 0.208%≤Al≤0.424%, 0.0036%≤B≤0.0041%, 0.0107%≤Zr≤0.15%, and the balance is Fe. 2. an electroslag remelting method of alloy as claimed in claim 1, is characterized in that, has the following steps: 1) The alloy raw material is vacuum melted and cast into a round bar, and after finishing, a remelted electrode rod for electroslag remelting of a high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy is obtained; 2) Take the components of the slag material, mix well, bake at 800°C for not less than 3 hours, and arc to melt the slag; The remelting electrode rod is inserted into the slag pool, and the voltage, current and chemical material are adjusted according to the diameter of the remelting electrode rod after the arc is energized; 3) Cooling and demoulding after remelting to obtain electroslag ingots; 4) The electroslag ingot is hot-processed and then forged into a bar. After solid solution and aging treatment, a high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy is obtained. 3. The method according to claim 2, characterized in that: the parts by weight of the components of the slag are: CaF ₂ : 65-75 parts; CaO: 8-15 parts; Al ₂ O ₃ : 10-18 parts parts; MgO: 5-11 parts. 4. The method according to claim 3, characterized in that: the parts by weight of the components of the slag are: CaF ₂ : 65-75 parts; CaO: 10-12 parts; Al ₂ O ₃ : 10-18 parts parts; MgO: 5-7 parts. 5. The method according to claim 2, characterized in that: the content of P in the electroslag ingot is not more than 30ppm, and the content of S is not more than 15ppm. 6. The method according to claim 2, characterized in that: when the diameter of the remelted electrode rod in step 2) is 80-150mm, the current is (3-4)±0.5kA, the voltage is (40-45 )±5V; when the diameter is 151~400mm, the current is (7~14)±0.5kA, and the voltage is (45~60)±2V. 7. The method according to claim 2, characterized in that: the high-strength copper-containing Ni-Fe-Cr-based age-hardening corrosion-resistant alloy has a low-temperature impact energy ≥ 61J when the ambient temperature is -60°C, and the room temperature Tensile strength ≥ 1030MPa, yield strength ≥ 860MPa, elongation ≥ 19%, reduction of area ≥ 25%, Rockwell hardness 30-40HRC, grain size ≥ 2.5.

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