ERNiCrMo-3 corrosion-resistant alloy welding wire and preparation method thereof

Abstract

The invention relates to a corrosion-resistant alloy welding wire, in particular to an ERNi CrMo-3 corrosion-resistant alloy welding wire and a preparation method thereof. The steel comprises the following chemical components in percentage by mass: greater than or equal to 64% of Ni, 21%-23% of Cr, 8.5%-10% of Mo, less than or equal to 0.2% of Fe, 0.1%-0.3% of Ti, 0.1%-0.25% of Al, 3.5%-4.15% of Nb, less than or equal to 0.2% of Cu, less than or equal to 0.02% of C, less than or equal to 0.5% of Mn, less than or equal to 0.35% of S i, less than or equal to 0.005% of S and less than or equal to 0.005% of P. By adopting vacuum induction melting and electroslag remelting, the content of all elements in the alloy can be accurately controlled, the content of impurity elements (H, O, N, S, P and the like) is effectively reduced, the content of oxygen and nitrogen is controlled to be not larger than 20 ppm, alloy components are more uniform and stable, and therefore the corrosion resistance and the high-temperature mechanical property of the welding wire are improved.

Description

Technical Field

[0001] The invention relates to a corrosion-resistant alloy welding wire, in particular to an ERNiCrMo-3 corrosion-resistant alloy welding wire and a preparation method thereof. Background Art

[0002] ERNiCrMo-3 corrosion-resistant alloy welding wire is widely used in chemical, marine, aerospace and other fields due to its excellent corrosion resistance, stable high temperature performance and good welding performance.

[0003] However, in the smelting preparation process, it is difficult for traditional processes to keep impurity elements such as oxygen (O) and nitrogen (N) at a low level. The presence of these impurity elements will not only reduce the corrosion resistance of the welding wire, but also weaken its high-temperature mechanical properties. Therefore, in a high-temperature, high-pressure, and highly corrosive working environment, welded parts made of ERNiCrMo-3 welding wire are prone to corrosion, deformation, and even cracking.

[0004] Therefore, in order to improve the corrosion resistance and high-temperature mechanical properties of the welding wire, it is urgent to provide an ERNiCrMo-3 corrosion-resistant alloy welding wire and a preparation method thereof. Summary of the invention

[0005] The purpose of the present invention is to solve the technical problem that the existing welding wire has poor corrosion resistance and high temperature mechanical properties, and to provide an ERNiCrMo-3 corrosion-resistant alloy welding wire and a preparation method thereof.

[0006] To solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0007] An ERNiCrMo-3 corrosion-resistant alloy welding wire, whose chemical composition, measured by mass percentage, includes:

[0008] Ni≥64%, Cr: 21%~23%, Mo: 8.5%~10%, Fe≤0.2%, Ti: 0.1%~0.3%, Al: 0.1%~0.25%, Nb: 3.5%~4.15%, Cu≤0.2%, C≤0.02%, Mn≤0.5%, Si≤0.35%, S≤0.005%, P≤0.005%.

[0009] A method for preparing ERNiCrMo-3 corrosion-resistant alloy welding wire comprises the following steps:

[0010] S1. According to the chemical composition of ERNiCrMo-3 corrosion-resistant alloy welding wire, weigh the corresponding electrolytic nickel, metal chromium, molybdenum bar, titanium plate, aluminum ingot, niobium bar and carbon;

[0011] S2. Evacuate the melting chamber of the vacuum induction melting furnace to a vacuum level not greater than 5 Pa;

[0012] The metal chromium and carbon are wrapped by electrolytic nickel and molybdenum bars and then placed in a crucible of a vacuum induction melting furnace for heating and melting to obtain molten steel;

[0013] After the molten steel is melted, niobium bars are added for refining; after the refining is completed, aluminum ingots and titanium plates are added to the refined molten steel to obtain alloy liquid after full melting;

[0014] S3, pouring out of the furnace to obtain alloy billet;

[0015] S4, setting electroslag remelting parameters, and using the alloy billet as an electrode of the electroslag remelting furnace;

[0016] The alloy billet is electroslag remelted in an electroslag remelting furnace, the alloy billet is melted to form molten droplets which enter the crystallizer, and the electroslag remelted billet is obtained after the crystallizer is cooled;

[0017] S5, placing the electroslag remelting billet in an electric heating furnace and heating it to 1170-1190°C;

[0018] After heating, the electroslag remelting billet is subjected to multiple forgings, with a deformation of 30% and a drawing and pressing amount of 50 mm for each forging. The starting forging temperature is not less than 1080°C, and the final forging temperature is not less than 930°C.

[0019] After forging is completed, a forging billet is obtained;

[0020] S6. Place the forging blank in an electric heating furnace and heat it to 1180° C. for 30 minutes;

[0021] After heating, the forging billet is hot rolled, with the initial rolling temperature not lower than 1120°C and the final rolling temperature not lower than 950°C, and the billet is formed by one hot rolling. After hot rolling, a hot rolled billet is obtained.

[0022] S7, removing surface defects of hot rolled slab;

[0023] The hot rolled billet is roughly drawn into a welding wire billet with a diameter of 2.5 mm, and then continuously annealed;

[0024] After annealing, the wire blank is drawn to a size that meets product specifications, completing the preparation of the ERNiCrMo-3 corrosion-resistant alloy welding wire.

[0025] Furthermore, in step S2, the specific method of encapsulating the metal chromium and carbon by electrolytic nickel and molybdenum strips is as follows:

[0026] Divide the electrolytic nickel into three parts, and place the first part of the electrolytic nickel in a crucible;

[0027] Divide the metal chromium and molybdenum strips into two equal parts, place the first part of metal chromium and carbon on the first part of electrolytic nickel, and place the first part of molybdenum strips and the second part of electrolytic nickel on the first part of metal chromium and carbon;

[0028] A second portion of metallic chromium is placed on the second portion of electrolytic nickel; a second portion of molybdenum strip and a third portion of electrolytic nickel are placed on the second portion of metallic chromium.

[0029] Furthermore, in step S2, the specific method of heating and smelting is:

[0030] Preheat the crucible with a preheating power of 200 kW;

[0031] After preheating, the power of the vacuum induction melting furnace is increased to 900kw to melt the raw materials in the crucible.

[0032] Furthermore, in step S2, the specific method of adding niobium bars for refining is:

[0033] Add niobium bars into the molten steel, raise the temperature to 1510-1530°C, and adjust the vacuum degree in the vacuum induction melting furnace to ≤2Pa;

[0034] Start refining, refining time is 60min, refining power is 750kw, vacuum degree is ≤2Pa during the whole refining period, and temperature cannot exceed 1500℃ during the refining process.

[0035] Further, in step S2, after refining is completed, an oxygen / nitrogen gas element content in the refined molten steel is detected using an oxygen and nitrogen analyzer;

[0036] If the gas element content of oxygen / nitrogen is less than or equal to 20ppm, add aluminum ingots and titanium plates to the refined molten steel, stir for 10 minutes after melting to obtain alloy liquid;

[0037] If the oxygen / nitrogen gas element content is greater than 20 ppm, refining is continued until the oxygen / nitrogen gas element content in the molten steel is less than or equal to 20 ppm.

[0038] Furthermore, step S3 is specifically as follows:

[0039] Fill the vacuum induction melting furnace with argon gas to make the pressure in the vacuum induction melting furnace 8000-9000Pa;

[0040] The alloy liquid in the crucible is poured into an alloy ingot mold at 1450-1470°C, and an alloy billet is obtained after cooling.

[0041] Furthermore, in step S4, the electroslag remelting parameters are set as follows:

[0042] The steady-state current of the electroslag remelting furnace was set to 10000 A, the voltage was set to 50 V, and the electroslag remelting rate was set to 5.5 kg / min.

[0043] Furthermore, in step S7, the specific method of continuous annealing is:

[0044] The welding wire blank is heated to 1020°C in a hydrogen protective atmosphere for annealing.

[0045] Compared with the prior art, the present invention has the following beneficial effects:

[0046] 1. The ERNiCrMo-3 corrosion-resistant alloy welding wire and the preparation method thereof provided by the present invention can improve the corrosion resistance and mechanical properties of the corrosion-resistant alloy welding wire by increasing the content of Ni element to ≥64%; by adopting the vacuum induction melting + electroslag remelting melting process, the content of impurity elements (O, N, S, P, etc.) can be effectively reduced, wherein the oxygen and nitrogen contents are controlled to be no more than 20 ppm, so that the alloy composition is more uniform and stable, thereby improving the corrosion resistance and high-temperature mechanical properties of the welding wire.

[0047] 2. The ERNiCrMo-3 corrosion-resistant alloy welding wire and the preparation method thereof provided by the present invention, since during the vacuum induction melting process, the raw materials are placed in a crucible for melting, the temperature at the bottom of the crucible is higher than the temperature at the top, and the metal chromium and carbon are wrapped by electrolytic nickel and molybdenum bars and then placed in the crucible of a vacuum induction melting furnace for heating and melting, the risk of metal chromium crusting due to uneven temperature and exposure to the vacuum induction melting furnace during the melting process can be avoided.

[0048] 3. The ERNiCrMo-3 corrosion-resistant alloy welding wire and its preparation method provided by the present invention optimize the internal organizational structure of the welding wire, refine the grains and make them evenly distributed during forging, hot rolling and cold drawing by reasonably controlling parameters such as heating temperature, holding time, deformation amount and intermediate heat treatment process, thereby improving the strength, toughness and plasticity of the welding wire, reducing the occurrence of internal defects and improving the quality and reliability of the product. DETAILED DESCRIPTION

[0049] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0050] The invention discloses an ERNiCrMo-3 corrosion-resistant alloy welding wire, whose chemical composition, measured by mass percentage, includes: Ni≥64%, Cr: 21%-23%, Mo: 8.5%-10%, Fe≤0.2%, Ti: 0.1%-0.3%, Al: 0.1%-0.25%, Nb: 3.5%-4.15%, Cu≤0.2%, C≤0.02%, Mn≤0.5%, Si≤0.35%, S≤0.005%, and P≤0.005%.

[0051] The preparation method of the above ERNiCrMo-3 corrosion resistant alloy welding wire is as follows:

[0052] 1) According to the chemical composition of ERNiCrMo-3 corrosion-resistant alloy welding wire, weigh the corresponding electrolytic nickel, metal chromium, molybdenum bar, titanium plate, aluminum ingot, niobium bar and carbon;

[0053] 2) evacuating the melting chamber of the vacuum induction melting furnace to a vacuum of no more than 5 Pa; wrapping the metal chromium and carbon with electrolytic nickel and molybdenum bars and then placing them in the crucible of the vacuum induction melting furnace for heating and melting to obtain molten steel;

[0054] The specific method of encapsulating metal chromium and carbon through electrolytic nickel and molybdenum strips is as follows:

[0055] The electrolytic nickel is divided into three parts, and the first part of the electrolytic nickel is placed in a crucible; the metal chromium and the molybdenum bar are divided into two parts, and the first part of the metal chromium and carbon are placed on the first part of the electrolytic nickel, and the first part of the molybdenum bar and the second part of the electrolytic nickel are placed on the first part of the metal chromium and carbon; the second part of the metal chromium is placed on the second electrolytic nickel; the second part of the molybdenum bar and the third part of the electrolytic nickel are placed on the second part of the metal chromium;

[0056] By placing the first portion of electrolytic nickel in the crucible, the second portion of electrolytic nickel on the first portion of metallic chromium, and the third portion of electrolytic nickel on the second portion of metallic chromium, the metallic chromium can be wrapped in the crucible, thereby preventing the metallic chromium from crusting on the surface due to uneven temperatures above and below the crucible and direct exposure of the metallic chromium to the vacuum induction melting furnace.

[0057] The specific method of heating and melting is:

[0058] The crucible is preheated with a preheating power of 200 kW; after the preheating is completed, the power of the vacuum induction melting furnace is increased to 900 kW to melt the raw materials in the crucible;

[0059] After the molten steel is melted, niobium bars are added for refining; since metallic niobium is an element that is prone to segregation, adding it after the molten steel is melted can reduce segregation.

[0060] The specific method of adding niobium bars for refining is:

[0061] Add niobium bars into the molten steel, raise the temperature to 1510-1530℃, adjust the vacuum degree in the vacuum induction melting furnace to ≤2Pa; start refining, the refining time is 60min, the refining power is 750kw, the vacuum degree is ≤2Pa during the whole refining period, and the temperature cannot exceed 1500℃ during the refining process;

[0062] After refining, an oxygen / nitrogen analyzer is used to detect the oxygen / nitrogen gas element content in the refined molten steel;

[0063] If the gas element content of oxygen / nitrogen is less than or equal to 20ppm, add aluminum ingots and titanium plates to the refined molten steel, stir for 10 minutes after melting to obtain alloy liquid;

[0064] Aluminum ingots and titanium plates are added after refining is completed and the gas element content is qualified because aluminum and titanium are active metals and burning may occur if added too early. If they are added after refining is completed and the gas element content is qualified, they can be taken out of the furnace after melting, which reduces the burning of aluminum and titanium.

[0065] If the oxygen / nitrogen gas element content is greater than 20 ppm, continue refining until the oxygen / nitrogen gas element content in the molten steel is less than or equal to 20 ppm;

[0066] Before leaving the furnace, the specific composition of the alloy liquid can be detected, and combined with the chemical composition of the ERNiCrMo-3 corrosion-resistant alloy welding wire, it can be determined whether to add corresponding raw materials; if additional raw materials are needed, add and melt them and stir for 10 minutes to complete the fine adjustment of the alloy liquid composition;

[0067] The material is added using a hopper to ensure that the vacuum induction melting furnace will not break the vacuum during the addition process;

[0068] 3) filling the vacuum induction melting furnace with argon gas to make the pressure in the vacuum induction melting furnace 8000-9000Pa; pouring the alloy liquid in the crucible into the alloy ingot mold at 1450-1470°C, and obtaining the alloy billet after cooling;

[0069] 4) The steady-state current of the electroslag remelting furnace is set to 10000A, the voltage is set to 50V, and the electroslag remelting rate is set to 5.5kg / min; the electroslag slag material of the electroslag remelting furnace is E50;

[0070] The alloy billet is used as an electrode of an electroslag remelting furnace; the shrinkage hole at the head of the electrode is directed downward to prevent the shrinkage hole from forming on the top due to excessive melting speed during the shrinkage compensation period of the electroslag remelting process;

[0071] The alloy billet is electroslag remelted in an electroslag remelting furnace, the alloy billet is melted to form molten droplets which enter the crystallizer, and the electroslag remelted billet is obtained after the crystallizer is cooled;

[0072] 5) placing the electroslag remelting billet in an electric heating furnace and heating it to 1170-1190°C;

[0073] After heating, the electroslag remelting billet is subjected to multiple forgings, with a deformation of 30% and a drawing and pressing amount of 50 mm for each forging. The starting forging temperature is not less than 1080°C, and the final forging temperature is not less than 930°C.

[0074] After forging is completed, a forging billet is obtained;

[0075] 6) Place the forging blank in an electric heating furnace and heat it to 1180°C for 30 minutes;

[0076] After heating, the forging billet is hot rolled, with the initial rolling temperature not lower than 1120°C and the final rolling temperature not lower than 950°C, and the billet is formed by one hot rolling. After hot rolling, a hot rolled billet is obtained.

[0077] 7) Remove surface defects of hot rolled billets;

[0078] Rough drawing the hot rolled billet into a welding wire billet with a diameter of 2.5 mm;

[0079] The welding wire blank is heated to 1020°C in a hydrogen protective atmosphere for annealing;

[0080] After annealing, the wire blank is drawn to a size that meets product specifications, completing the preparation of the ERNiCrMo-3 corrosion-resistant alloy welding wire.

[0081] Specific examples are given below.

[0082] Example 1

[0083] (1) Raw material preparation:

[0084] Electrolytic nickel, metallic chromium, molybdenum bars, niobium bars, titanium plates, aluminum ingots and carbon with industrial high purity standards are selected as raw materials, and the proportions are accurately matched according to the standard chemical composition requirements of ERNiCrMo-3 alloy to control the content of each element within the specified range, among which Ni ≥ 64%, Cr: 21% ~ 23%, Mo: 8.5% ~ 10%, Fe ≤ 0.2%, Ti: 0.1% ~ 0.3%, Al: 0.1% ~ 0.25%, Nb: 3.5% ~ 4.15%, Cu ≤ 0.2%, C ≤ 0.02%, Mn ≤ 0.5%, Si ≤ 0.35%, S ≤ 0.005%, and P ≤ 0.005%.

[0085] (2) Feeding method:

[0086] During the charging process, the vacuum in the melting chamber of the vacuum induction melting furnace must not be broken, and a charging hopper is used to add materials.

[0087] (3) The order of adding materials is:

[0088] ① Set aside some electrolytic nickel and add the rest;

[0089] ② Add metallic chromium and all carbon in two batches, and add molybdenum strips and electrolytic nickel on each batch of metallic chromium;

[0090] ③ Leave all titanium plates, aluminum ingots, and niobium bars;

[0091] ④ Add niobium bars after the molten steel is melted;

[0092] ⑤ After the oxygen and nitrogen gas element content is qualified after refining, add aluminum ingots and titanium plates;

[0093] (4) Melting period:

[0094] Preheating the crucible of the vacuum induction melting furnace with a preheating power of 200 kW;

[0095] After preheating, increase the power of the vacuum induction melting furnace to 900kw to enter the melting period; add materials in time during the melting process, and no molten steel can be seen during the addition; if splashing occurs during the melting process, reduce the power in time to prevent bridging.

[0096] (5) Refining period:

[0097] Add niobium bars into the molten steel, raise the temperature to 1510-1530°C, and adjust the vacuum degree in the vacuum induction melting furnace to ≤2Pa;

[0098] Start refining, refining time is 60min, refining power is 750kw, vacuum degree is ≤2Pa during the whole refining period, and temperature cannot exceed 1500℃ during the refining process.

[0099] (6) Fine-tuning the periodization:

[0100] According to the chemical composition test results of the alloy liquid and the chemical composition of the ERNiCrMo-3 corrosion-resistant alloy welding wire, it is determined whether to add raw materials. If additional raw materials are added, stir them for 10 minutes after adding and melting.

[0101] (7) Pouring out of the furnace:

[0102] Fill the vacuum induction melting furnace with argon gas to make the pressure in the vacuum induction melting furnace 8000-9000Pa; pour the alloy liquid in the crucible into the alloy ingot mold at 1450-1470°C.

[0103] (8) Electroslag remelting:

[0104] The alloy billet is used as a consumable electrode in an electroslag remelting furnace;

[0105] The surface of the electrode rod and the dummy electrode (copper) should be ground clean, and the shrinkage hole of the electrode head should be facing downward to prevent the shrinkage hole from forming on the top due to excessive melting speed during the shrinkage compensation period of the electroslag process;

[0106] The current setting value in the stable period is 10000A, the voltage setting value is 50V, the electroslag remelting speed is set to 5.5kg / min, and the slag material is E50.

[0107] (9) Forging:

[0108] The heating temperature is 1180±10℃, and the steel is taken out of the furnace for forging after reaching the temperature. The transfer time is not more than 60s, the start forging temperature is not less than 1080℃, and the final forging temperature is not less than 930℃. The transfer speed should be fast. The deformation amount of each fire is most appropriately controlled at 30%, and the drawing pressure is controlled at 50mm.

[0109] The drawing process is adopted, and the specific forging process is as follows:

[0110]

[0111]

[0112] (10) Hot rolling:

[0113] The forged billet is put into the furnace and heated to 1180℃, the heating time is 30min, the transfer time is no more than 60s, the initial forging temperature is 1120℃, the final forging temperature is 950℃, and it is rolled into shape in one fire, hot rolled from Φ160mm to Φ10mm.

[0114] (11) Continuous annealing:

[0115] Annealing temperature: 1020°C, annealing in hydrogen atmosphere;

[0116] (12) Cold rolling:

[0117] The incoming material is first surface treated, then rough drawn to a specification of Φ2.5mm, continuously annealed, and fine drawn to the final finished product specification.

[0118] Comparative Example 1

[0119] (1) Raw material preparation:

[0120] Electrolytic nickel, metallic chromium, molybdenum bars, niobium bars, titanium plates, aluminum ingots and carbon with industrial high purity standards are selected as raw materials, and the proportions are accurately matched according to the standard chemical composition requirements of ERNiCrMo-3 alloy to control the content of each element within the specified range, among which Ni ≥ 64%, Cr: 21% ~ 23%, Mo: 8.5% ~ 10%, Fe ≤ 0.2%, Ti: 0.1% ~ 0.3%, Al: 0.1% ~ 0.25%, Nb: 3.5% ~ 4.15%, Cu ≤ 0.2%, C ≤ 0.02%, Mn ≤ 0.5%, Si ≤ 0.35%, S ≤ 0.005%, and P ≤ 0.005%.

[0121] (2) Feeding method:

[0122] During the charging process, the vacuum in the melting chamber of the vacuum induction melting furnace must not be broken, and a charging hopper is used to add materials.

[0123] (3) The order of adding materials is:

[0124] ① Set aside some electrolytic nickel and add the rest;

[0125] ② Add metallic chromium and all carbon in two batches, and add molybdenum strips and electrolytic nickel on each batch of metallic chromium;

[0126] ③ Leave all titanium plates, aluminum ingots, and niobium bars;

[0127] ④ Add niobium bars after the molten steel is melted;

[0128] ⑤ After the oxygen and nitrogen gas element content is qualified after refining, add aluminum ingots and titanium plates;

[0129] (4) Melting period:

[0130] Preheating the crucible of the vacuum induction melting furnace with a preheating power of 200 kW;

[0131] After preheating, increase the power of the vacuum induction melting furnace to 900kw to enter the melting period; add materials in time during the melting process, and no molten steel can be seen during the addition; if splashing occurs during the melting process, reduce the power in time to prevent bridging.

[0132] (5) Refining period:

[0133] Add niobium bars into the molten steel, raise the temperature to 1510-1530°C, and adjust the vacuum degree in the vacuum induction melting furnace to ≤2Pa;

[0134] Start refining, refining time is 60min, refining power is 750kw, vacuum degree is ≤2Pa during the whole refining period, and temperature cannot exceed 1500℃ during the refining process.

[0135] (6) Fine-tuning the periodization:

[0136] According to the chemical composition test results of the alloy liquid and the chemical composition of the ERNiCrMo-3 corrosion-resistant alloy welding wire, it is determined whether to add raw materials. If additional raw materials are added, stir them for 10 minutes after adding and melting.

[0137] (7) Pouring out of the furnace:

[0138] Fill the vacuum induction melting furnace with argon gas to make the pressure in the vacuum induction melting furnace 8000-9000Pa; pour the alloy liquid in the crucible into the alloy ingot mold at 1450-1470°C.

[0139] (8) Forging:

[0140] The heating temperature is 1180±10℃, and the steel is taken out of the furnace for forging after reaching the temperature. The transfer time is not more than 60s, the start forging temperature is not less than 1080℃, and the final forging temperature is not less than 930℃. The transfer speed should be fast. The deformation amount of each fire is most appropriately controlled at 30%, and the drawing pressure is controlled at 50mm.

[0141] The drawing process is adopted, and the specific forging process is as follows:

[0142]

[0143] (9) Hot rolling:

[0144] The forged billet is put into the furnace and heated to 1180℃, the heating time is 30min, the transfer time is no more than 60s, the initial forging temperature is 1120℃, the final forging temperature is 950℃, and it is rolled into shape in one fire, hot rolled from Φ160mm to Φ10mm.

[0145] (10) Continuous annealing: annealing temperature 1020°C, annealing in hydrogen atmosphere;

[0146] (11) Cold rolling: The incoming material is first surface treated, then rough drawn to a specification of Φ2.5mm, continuously annealed, and fine drawn to the final finished product specification.

[0147] Comparative Example 2:

[0148] (1) Raw material preparation:

[0149] Electrolytic nickel, metallic chromium, molybdenum bars, niobium bars, titanium plates, aluminum ingots and carbon with industrial high purity standards are selected as raw materials, and the proportions are accurately matched according to the standard chemical composition requirements of ERNiCrMo-3 alloy to control the content of each element within the specified range, among which Ni ≥ 64%, Cr: 21% ~ 23%, Mo: 8.5% ~ 10%, Fe ≤ 0.2%, Ti: 0.1% ~ 0.3%, Al: 0.1% ~ 0.25%, Nb: 3.5% ~ 4.15%, Cu ≤ 0.2%, C ≤ 0.02%, Mn ≤ 0.5%, Si ≤ 0.35%, S ≤ 0.005%, and P ≤ 0.005%.

[0150] (2) Feeding method:

[0151] During the charging process, the vacuum in the melting chamber of the vacuum induction melting furnace must not be broken, and a charging hopper is used to add materials.

[0152] (3) The order of adding materials is:

[0153] ① Set aside some electrolytic nickel and add the rest;

[0154] ② Add metallic chromium and all carbon in two batches, and add molybdenum strips and electrolytic nickel on each batch of metallic chromium;

[0155] ③ Leave all titanium plates, aluminum ingots, and niobium bars;

[0156] ④ Add niobium bars after the molten steel is melted;

[0157] ⑤ After the oxygen and nitrogen gas element content is qualified after refining, add aluminum ingots and titanium plates;

[0158] (4) Melting period:

[0159] Preheating the crucible of the vacuum induction melting furnace with a preheating power of 200 kW;

[0160] After preheating, increase the power of the vacuum induction melting furnace to 900kw to enter the melting period; add materials in time during the melting process, and no molten steel can be seen during the addition; if splashing occurs during the melting process, reduce the power in time to prevent bridging.

[0161] (5) Refining period:

[0162] Add niobium bars into the molten steel, raise the temperature to 1510-1530°C, and adjust the vacuum degree in the vacuum induction melting furnace to ≤2Pa;

[0163] Start refining, refining time is 60min, refining power is 750kw, vacuum degree is ≤2Pa during the whole refining period, and temperature cannot exceed 1500℃ during the refining process.

[0164] (6) Fine-tuning the periodization:

[0165] According to the chemical composition test results of the alloy liquid and the chemical composition of the ERNiCrMo-3 corrosion-resistant alloy welding wire, it is determined whether to add raw materials. If additional raw materials are added, stir them for 10 minutes after adding and melting.

[0166] (7) Pouring out of the furnace:

[0167] Fill the vacuum induction melting furnace with argon gas to make the pressure in the vacuum induction melting furnace 8000-9000Pa; pour the alloy liquid in the crucible into the alloy ingot mold at 1450-1470°C.

[0168] (8) Electroslag remelting:

[0169] The alloy billet is used as a consumable electrode in an electroslag remelting furnace;

[0170] The surface of the electrode rod and the dummy electrode (copper) should be ground clean, and the shrinkage hole of the electrode head should be facing downward to prevent the shrinkage hole from forming on the top due to excessive melting speed during the shrinkage compensation period of the electroslag process;

[0171] The current setting value in the stable period is 10000A, the voltage setting value is 50V, the electroslag remelting speed is set to 5.5kg / min, and the slag material is E50.

[0172] (9) Forging: Heating temperature is 1150±10℃, and the steel is taken out of the furnace for forging after reaching the temperature. The transfer time is not more than 60s, the start forging temperature is not less than 1050℃, and the final forging temperature is not less than 900℃. The transfer speed should be fast. The deformation of each fire is most appropriately controlled at 30%, and the drawing pressure is controlled at 50mm.

[0173] The drawing process is adopted, and the specific forging process is as follows:

[0174]

[0175] (10) Hot rolling: The forged billet is placed in a furnace and heated to 1180°C for 30 min, with a transfer time of no more than 60 s, an initial forging temperature of 1120°C, a final forging temperature of 950°C, and one-fire rolling forming, from Φ160 mm to Φ10 mm.

[0176] (11) Continuous annealing: annealing temperature 1020°C, annealing in hydrogen atmosphere;

[0177] (12) Cold rolling: The incoming material is first surface treated, then rough drawn to a specification of Φ2.5mm, continuously annealed, and fine drawn to the final finished product specification.

[0178] Comparative Example 3:

[0179] (1) Raw material preparation:

[0180] Electrolytic nickel, metallic chromium, molybdenum bars, niobium bars, titanium plates, aluminum ingots and carbon with industrial high purity standards are selected as raw materials, and the proportions are accurately matched according to the standard chemical composition requirements of ERNiCrMo-3 alloy to control the content of each element within the specified range, among which Ni ≥ 64%, Cr: 21% ~ 23%, Mo: 8.5% ~ 10%, Fe ≤ 0.2%, Ti: 0.1% ~ 0.3%, Al: 0.1% ~ 0.25%, Nb: 3.5% ~ 4.15%, Cu ≤ 0.2%, C ≤ 0.02%, Mn ≤ 0.5%, Si ≤ 0.35%, S ≤ 0.005%, and P ≤ 0.005%.

[0181] (2) Feeding method:

[0182] During the charging process, the vacuum in the melting chamber of the vacuum induction melting furnace must not be broken, and a charging hopper is used to add materials.

[0183] (3) The order of adding materials is:

[0184] ① Set aside some electrolytic nickel and add the rest;

[0185] ② Add metallic chromium and all carbon in two batches, and add molybdenum strips and electrolytic nickel on each batch of metallic chromium;

[0186] ③ Leave all titanium plates, aluminum ingots, and niobium bars;

[0187] ④ Add niobium bars after the molten steel is melted;

[0188] ⑤ After the oxygen and nitrogen gas element content is qualified after refining, add aluminum ingots and titanium plates;

[0189] (4) Melting period:

[0190] Preheating the crucible of the vacuum induction melting furnace with a preheating power of 200 kW;

[0191] After preheating, increase the power of the vacuum induction melting furnace to 900kw to enter the melting period; add materials in time during the melting process, and no molten steel can be seen during the addition; if splashing occurs during the melting process, reduce the power in time to prevent bridging.

[0192] (5) Refining period:

[0193] Add niobium bars into the molten steel, raise the temperature to 1510-1530°C, and adjust the vacuum degree in the vacuum induction melting furnace to ≤2Pa;

[0194] Start refining, refining time is 60min, refining power is 750kw, vacuum degree is ≤2Pa during the whole refining period, and temperature cannot exceed 1500℃ during the refining process.

[0195] (6) Fine-tuning the periodization:

[0196] According to the chemical composition test results of the alloy liquid and the chemical composition of the ERNiCrMo-3 corrosion-resistant alloy welding wire, it is determined whether to add raw materials. If additional raw materials are added, stir them for 10 minutes after adding and melting.

[0197] (7) Pouring out of the furnace:

[0198] Fill the vacuum induction melting furnace with argon gas to make the pressure in the vacuum induction melting furnace 8000Pa; pour the alloy liquid in the crucible into the alloy ingot mold at 1450-1470°C.

[0199] (8) Electroslag remelting:

[0200] The alloy billet is used as a consumable electrode in an electroslag remelting furnace;

[0201] The surface of the electrode rod and the dummy electrode (copper) should be ground clean, and the shrinkage hole of the electrode head should be facing downward to prevent the shrinkage hole from forming on the top due to excessive melting speed during the shrinkage compensation period of the electroslag process;

[0202] The current setting value in the stable period is 10000A, the voltage setting value is 50V, the electroslag remelting speed is set to 5.5kg / min, and the slag material is E50.

[0203] (9) Forging: Heating temperature is 1150±10℃, and the steel is taken out of the furnace for forging after reaching the temperature. The transfer time is not more than 60s, the start forging temperature is not less than 1050℃, and the final forging temperature is not less than 930℃. The transfer speed should be fast. The deformation of each fire is most appropriately controlled at 30%, and the drawing pressure is controlled at 50mm.

[0204] The drawing process is adopted, and the specific forging process is as follows:

[0205]

[0206] (10) Hot rolling:

[0207] The forged billet is put into the furnace and heated to 1180℃, the heating time is 30min, the transfer time is no more than 60s, the initial forging temperature is 1120℃, the final forging temperature is 950℃, and it is rolled into shape in one fire, hot rolled from Φ160mm to Φ10mm.

[0208] (11) Continuous annealing:

[0209] Annealing temperature: 1020℃, annealing in atmosphere;

[0210] (12) Cold rolling:

[0211] The incoming material is first surface treated, then rough drawn to a specification of Φ2.5mm, annealed, and fine drawn to the final finished product specification.

[0212] When the raw materials and chemical composition contents are the same, compared with Example 1, Example 1 adopts single vacuum melting for melting and then directly forging, and in the forging process of Example 2, the forging temperature is reduced to 1150°C and the start forging temperature is reduced to 1050°C; and in the annealing process of the welding wire in Example 3, annealing is performed under atmospheric conditions.

[0213] In addition, a conventional (Ni content ≥ 58%) ERNiCrMo-3 corrosion-resistant alloy welding wire on the market was selected as comparative example 4.

[0214] The chemical compositions of the ERNiCrMo-3 corrosion-resistant alloy welding wires of Example 1 and Comparative Examples 1-4 were tested, and the test results are shown in Table 1.

[0215] Table 1: Chemical composition comparison table (unit: %)

[0216]

[0217] The non-metallic inclusion grade and mechanical properties (such as tensile strength and yield strength) of the ERNiCrMo-3 corrosion-resistant alloy welding wires prepared in Example 1 and Comparative Examples 1-4 were tested. The test results are shown in Table 2.

[0218] Table 2: Mechanical properties comparison table

[0219]

[0220] Comparative Example 1: A single vacuum induction melting method is adopted, and forging is directly performed without electroslag remelting after vacuum induction melting; the prepared welding wire has serious component segregation, high inclusion content, and poor mechanical properties.

[0221] Comparative Example 2: During the forging process, the forging temperature was reduced to 1150°C and the start forging temperature was reduced to 1050°C; the internal structure of the bar after forging was uneven, the mechanical properties decreased, cracks were easily generated during the subsequent rolling and cold drawing processes, and the yield rate was reduced.

[0222] Comparative Example 3: During the annealing process of the welding wire, annealing was performed under atmospheric conditions. After annealing, the surface was severely oxidized, spatter was severe during welding, and the welding effect was poor.

[0223] Comparative Example 4 is a conventional (Ni content ≥ 58%) ERNiCrMo-3 corrosion-resistant alloy welding wire on the market.

[0224] It is not difficult to see from Table 1 that the contents of harmful impurity elements: S, P, O, and N in the ERNiCrMo-3 corrosion-resistant alloy welding wire prepared in Example 1 are all lower than the contents of harmful impurity elements in the ERNiCrMo-3 corrosion-resistant alloy welding wire prepared in Comparative Examples 1-4.

[0225] Therefore, by adopting the vacuum induction melting + electroslag remelting process + forging process with an initial forging temperature of not less than 1080°C and a final forging temperature of not less than 930°C + hydrogen atmosphere annealing in Example 1, an ERNiCrMo-3 corrosion-resistant alloy welding wire with a low content of harmful impurity elements can be obtained.

[0226] It is not difficult to see from Table 2 that the level of non-metallic inclusions in the ERNiCrMo-3 corrosion-resistant alloy welding wire prepared in Example 1 is lower than the content of harmful impurity elements in the ERNiCrMo-3 corrosion-resistant alloy welding wire prepared in Comparative Example 1.

[0227] At the same time, the tensile strength and yield strength of the ERNiCrMo-3 corrosion-resistant alloy welding wire prepared in Example 1 are higher than the tensile strength and yield strength of the ERNiCrMo-3 corrosion-resistant alloy welding wire prepared in Comparative Examples 1-4.

[0228] Moreover, compared with the ERNiCrMo-3 corrosion-resistant alloy welding wire of comparative example 4, Example 1 can increase the Ni element content while adopting a preparation process of vacuum induction melting + electroslag remelting process + a forging process with an initial forging temperature of not less than 1080°C and a final forging temperature of not less than 930°C + hydrogen atmosphere annealing to double the tensile strength and yield strength.

[0229] Therefore, the preparation method of the present invention can effectively reduce the content of harmful impurity elements S, P, O, and N in the ERNiCrMo-3 corrosion-resistant alloy welding wire, and improve the mechanical properties (tensile strength and yield strength) of the ERNiCrMo-3 corrosion-resistant alloy welding wire, which has significant advantages.

[0230] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An ERNiCrMo-3 corrosion-resistant alloy welding wire, characterized in that: In terms of mass percentage, its chemical composition includes: Ni≥64%, Cr: 21%~23%, Mo: 8.5%~10%, Fe≤0.2%, Ti: 0.1%~0.3%, Al: 0.1%~0.25%, Nb: 3.5%~4.15%, Cu≤0.2%, C≤0.02%, Mn≤0.5%, Si≤0.35%, S≤0.005%, P≤0.005%.

2. A method for preparing ERNiCrMo-3 corrosion-resistant alloy welding wire, characterized in that: The steps include: S1. According to the chemical composition of ERNiCrMo-3 corrosion-resistant alloy welding wire, weigh the corresponding electrolytic nickel, metal chromium, molybdenum bar, titanium plate, aluminum ingot, niobium bar and carbon; S2. Evacuate the melting chamber of the vacuum induction melting furnace to a vacuum level not greater than 5 Pa; The metal chromium and carbon are wrapped by electrolytic nickel and molybdenum bars and then placed in a crucible of a vacuum induction melting furnace for heating and melting to obtain molten steel; After the molten steel is melted, niobium bars are added for refining; after the refining is completed, aluminum ingots and titanium plates are added to the refined molten steel to obtain alloy liquid after full melting; S3, pouring out of the furnace to obtain alloy billet; S4, setting electroslag remelting parameters, and using the alloy billet as an electrode of the electroslag remelting furnace; The alloy billet is electroslag remelted in an electroslag remelting furnace, the alloy billet is melted to form molten droplets which enter the crystallizer, and the electroslag remelted billet is obtained after the crystallizer is cooled; S5, placing the electroslag remelting billet in an electric heating furnace and heating it to 1170-1190°C; After heating, the electroslag remelting billet is subjected to multiple forgings, with a deformation of 30% and a drawing and pressing amount of 50 mm for each forging. The starting forging temperature is not less than 1080°C, and the final forging temperature is not less than 930°C. After forging is completed, a forging billet is obtained; S6. Place the forging blank in an electric heating furnace and heat it to 1180° C. for 30 minutes; After heating, the forging billet is hot rolled, with the initial rolling temperature not lower than 1120°C and the final rolling temperature not lower than 950°C, and the billet is formed by one hot rolling. After hot rolling, a hot rolled billet is obtained. S7, removing surface defects of hot rolled slab; The hot rolled billet is roughly drawn into a welding wire billet with a diameter of 2.5 mm, and then continuously annealed; After annealing, the welding wire blank is finely drawn to a size that meets product specifications, completing the preparation of ERNiCrMo-3 corrosion-resistant alloy welding wire.

3. The method for preparing the ERNiCrMo-3 corrosion-resistant alloy welding wire according to claim 2, characterized in that: In step S2, the specific method of encapsulating metal chromium and carbon by electrolytic nickel and molybdenum strips is as follows: Divide the electrolytic nickel into three parts, and place the first part of the electrolytic nickel in a crucible; Divide the metal chromium and molybdenum strips into two equal parts, place the first part of metal chromium and carbon on the first part of electrolytic nickel, and place the first part of molybdenum strips and the second part of electrolytic nickel on the first part of metal chromium and carbon; A second portion of metallic chromium is placed on the second portion of electrolytic nickel; a second portion of molybdenum strip and a third portion of electrolytic nickel are placed on the second portion of metallic chromium.

4. The method for preparing the ERNiCrMo-3 corrosion-resistant alloy welding wire according to claim 2, characterized in that: In step S2, the specific method of heating and melting is: Preheat the crucible with a preheating power of 200 kW; After preheating, the power of the vacuum induction melting furnace is increased to 900kw to melt the raw materials in the crucible.

5. The method for preparing the ERNiCrMo-3 corrosion-resistant alloy welding wire according to claim 2, characterized in that: In step S2, the specific method of adding niobium bars for refining is: Add niobium bars into the molten steel, raise the temperature to 1510-1530°C, and adjust the vacuum degree in the vacuum induction melting furnace to ≤2Pa; Start refining, refining time is 60min, refining power is 750kw, vacuum degree is ≤2Pa during the whole refining period, and temperature cannot exceed 1500℃ during the refining process.

6. The method for preparing the ERNiCrMo-3 corrosion resistant alloy welding wire according to claim 2, characterized in that: In step S2, after refining is completed, an oxygen / nitrogen gas element content in the refined molten steel is detected using an oxygen and nitrogen analyzer; If the gas element content of oxygen / nitrogen is less than or equal to 20ppm, add aluminum ingots and titanium plates to the refined molten steel, stir for 10 minutes after melting to obtain alloy liquid; If the oxygen / nitrogen gas element content is greater than 20 ppm, refining is continued until the oxygen / nitrogen gas element content in the molten steel is less than or equal to 20 ppm.

7. The method for preparing the ERNiCrMo-3 corrosion-resistant alloy welding wire according to claim 2, characterized in that: Step S3 is specifically as follows: Fill the vacuum induction melting furnace with argon gas to make the pressure in the vacuum induction melting furnace 8000-9000Pa; The alloy liquid in the crucible is poured into an alloy ingot mold at 1450-1470°C, and an alloy billet is obtained after cooling.

8. The method for preparing the ERNiCrMo-3 corrosion-resistant alloy welding wire according to claim 2, characterized in that: In step S4, the electroslag remelting parameters are set as follows: The steady-state current of the electroslag remelting furnace was set to 10000 A, the voltage was set to 50 V, and the electroslag remelting rate was set to 5.5 kg / min.

9. The method for preparing the ERNiCrMo-3 corrosion-resistant alloy welding wire according to claim 2, characterized in that: In step S7, the specific method of continuous annealing is: The welding wire blank is heated to 1020°C in a hydrogen protective atmosphere for annealing.

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