A gh4169 alloy and a vacuum smelting method thereof

Abstract

The application provides a vacuum smelting method of GH4169, which comprises the following steps: S1, leaving molten steel in a vacuum induction furnace, wherein the molten steel comprises one or more of pure iron, metal nickel, SUS316, GH4080A and GH4169, and the vacuum induction furnace is kept in a state of being powered and heated and being vacuumized; S2, pretreating raw materials, wherein the returned materials of GH4169 and nickel plates, pure iron, aluminum blocks and titanium plates are subjected to rust removal treatment, and the returned materials are cut to complete the pretreatment of the raw materials; S3, batching, wherein the elements of the GH4169 alloy, the steel type composition and the quality of the molten steel in the step S1 are used for accurate batching; and S4, charging and S5, alloy melting. The vacuum hot charging technology used in the application improves the loose bulk density of the furnace charge of the vacuum induction furnace, can avoid the "bridge" phenomenon in the smelting process, is beneficial to the smooth running of the smelting process, and reduces the smelting time.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature alloy smelting, in particular to a GH4169 alloy and a vacuum smelting method thereof. BACKGROUND

[0002] GH4169 is a precipitation-strengthened nickel-based wrought superalloy, the matrix of which is a Ni-Cr solid solution, containing more than 50% of Ni by mass, and can withstand high temperatures of about 650 DEG C. It is similar to the American brand Inconel718, has good comprehensive performance in the temperature range of-253 DEG C to 650 DEG C, and has the highest yield strength below 650 DEG C among wrought superalloys, and also has good fatigue resistance, radiation resistance, oxidation resistance, corrosion resistance, and good processing performance and welding performance. The chemical composition of the alloy is mainly divided into three categories: ordinary composition, high-quality composition, and high-purity composition, as shown in Table 1. High-quality and high-purity GH4169 puts forward higher requirements for oxygen, nitrogen and trace harmful elements in the alloy. The GH4169 alloy for nuclear energy application needs to control the content of boron (other element compositions remain unchanged), and the specific content is determined by negotiation between the supplier and the demander. When the content of boron is less than or equal to 0.0020wt.%, in order to distinguish from the GH4169 alloy used in the aerospace industry, the alloy brand is GH4169A.

[0003] Vacuum induction melting (VIM for short) is a process in which the coil is energized to produce eddy current to melt the metal under closed vacuum conditions, and can be used to smelt high-purity metals and alloys. Because of the smelting under vacuum, it is easy to remove nitrogen, hydrogen, oxygen and carbon in the molten steel and alloy to a much lower level than smelting under normal pressure. In addition, for impurity elements (copper, zinc, lead, antimony, bismuth, tin and arsenic, etc.) whose vapor pressure is higher than that of the base metal at the smelting temperature, they can be removed by volatilization, and the composition of active elements such as aluminum, titanium, boron and zirconium which need to be added in the alloy can be easily controlled. Therefore, the vacuum induction furnace plays a crucial role in accurately controlling the content level of gas, non-metallic inclusions and trace harmful impurities in steel.

[0004] In order to avoid the reaction and absorption of high-temperature solid raw materials and bare liquid steel with oxygen and nitrogen in the air, the air in the smelting cavity must be removed as much as possible during the vacuum induction furnace smelting process, and the vacuum degree of the smelting cavity is generally required to be less than or equal to 20 Pa before power heating is allowed. If the vacuum is broken, the smelting cavity must be evacuated before power heating, and the evacuation time is generally about one hour.

[0005] Compared with the technologies of patents CN108517427A, CN112524950A, CN1137275C, CN111455199A, CN115305404A and CN106222460B, all of which adopt vacuum induction furnace smelting of high-temperature alloy, but none of which adopts vacuum hot charging method for charging and smelting. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a vacuum smelting method of GH4169 to solve the problem that conventional methods need to be vacuumized in advance in vacuum smelting.

[0007] To solve the above problems, the present application provides a vacuum smelting method of GH4169, comprising the following steps:

[0008] S1: holding molten steel: holding the molten steel in the vacuum induction furnace, the molten steel comprising one or more of pure iron, metal nickel, SUS316, GH4080A and GH4169, and keeping the vacuum induction furnace in the state of being powered and heated and being vacuumized;

[0009] S2: raw material pretreatment: selecting GH4169 and return materials of nickel plate, pure iron, aluminum block and titanium plate for rust removal treatment, and cutting the return materials to complete the pretreatment of raw materials;

[0010] S3: batching: according to the element types of GH4169 alloy and the steel grade composition and quality of the molten steel in step S1, accurate batching is performed, and the chemical composition of the GH4169 alloy comprises:

[0011] C: ≤0.080%; Cr: 17.0%-21.0%; Ni: 50.0%-55.0%; Co: ≤1.0%; Mo: 2.80%-3.30%; Al: 0.30%-0.70%; Ti: 0.75%-1.15%; Nb: 4.75%-5.50%; the balance is iron and other unavoidable impurities;

[0012] S4: charging: under the premise of not damaging the vacuum of the vacuum induction furnace, according to the batching result of step S3, raw materials are charged from the top charging bin and side charging bin of the vacuum induction furnace, the raw materials comprising one or more of the return materials of step S2 and high-purity graphite block, pure iron, metal chromium, metal nickel, metal molybdenum, metal niobium, metal aluminum, metal titanium plate, boron iron, phosphorus iron and nickel-magnesium alloy, and the vacuum induction furnace is powered and heated and vacuumized during the charging process;

[0013] S5: alloy melting: the remaining molten steel melts the raw materials of the charging in step S4 into a metal liquid by physical heat conduction. After mixing, the alloy liquid is formed, and the raw materials are continuously heated by the vacuum induction furnace in a small to large step power mode to complete the vacuum smelting.

[0014] As a preferred solution, in step S2, the cutting condition is that the return material is cut to a size of less than or equal to 200mmx200mmx200mm.

[0015] As a preferred solution, in step S3, the chemical composition of the GH4169 alloy includes:

[0016] C: 0.015%-0.060%; Cr: 17.0%-21.0%; Ni: 50.0%-55.0%; Co: ≤1.0%;

[0017] Mo: 2.80%-3.30%; Al: 0.30%-0.70%; Ti: 0.75%-1.15%; Nb: 5.00%-5.50%; the balance is iron and other inevitable impurities.

[0018] As a preferred solution, the chemical composition of the GH4169 alloy includes:

[0019] C: 0.012%-0.036%; Cr: 17.0%-19.0%; Ni: 52.0%-55.0%; Co: ≤1.0%;

[0020] Mo: 2.80%-3.15%; Al: 0.35%-0.65%; Ti: 0.75%-1.15%; Nb: 5.20%-5.50%; Fe: 16.0%-19.0%, the balance is other inevitable impurities.

[0021] As a preferred solution, in step S4, the charging sequence is: high-melting-point raw materials are added first, and raw materials are added to the vacuum induction furnace in order from large to small according to the size of the raw materials.

[0022] As a preferred solution, in step S5, the weight of the remaining molten steel is 15%-60% of the mass of the alloy liquid.

[0023] As a preferred solution, the weight of the molten steel is 20%-50% of the mass of the alloy liquid.

[0024] Another technical problem to be solved by the present application is to provide a GH4169 alloy prepared by the above method.

[0025] In order to solve the above problems, the application provides a GH4169 alloy prepared by the above preparation method.

[0026] Compared with the prior art, the application has the following advantages:

[0027] 1) Since the charging process does not destroy the high vacuum state (generally less than 20 Pa) of the upper furnace, the vacuum degree requirement for power-on smelting is met. Compared with the method of destroying the vacuum for charging, the smelting cavity does not need to be vacuumed before power-on heating, but is directly powered on during the charging process, thereby shortening the smelting time by more than 1 hour.

[0028] 2) Since the upper furnace hot molten steel of 15-60% of the total charging amount of the furnace is left, a large amount of physical heat is brought in by the hot molten steel, and power is already on during the charging process, so a relatively stable metal molten pool can be quickly formed during the smelting process, thereby accelerating the melting speed of the solid charge, significantly shortening the smelting cycle, reducing the power consumption per ton of steel, and improving the labor productivity.

[0029] 3) Since the liquid molten steel is left, after the refractory metal (such as molybdenum metal) and the large block charge (such as the return material, pure iron, and nickel plate) are preferentially added, the liquid molten steel can flow and fill in the gaps of the charge. On the one hand, the lower charge of the crucible is compacted to meet the scientific charging requirement of "tight at the bottom and loose at the top" of the vacuum induction furnace; on the other hand, since the liquid molten steel flows and fills in the gaps of the charge, the loose density of the charge of the vacuum induction furnace is improved, and other remaining charges do not need to be added during the smelting process; and thirdly, the "bridge" phenomenon of the large-size charge during the smelting process is avoided, which is beneficial to the smooth progress of the smelting process and reduces the smelting time.

[0030] 4) Since the liquid molten steel is left and power is on at the same time as the charging under the vacuum state, compared with the method of destroying the vacuum for charging, the refractory material is always at a high temperature, and the temperature drop is significantly reduced, thereby greatly reducing the tendency of cracks in the refractory material due to rapid cooling and heating, which is beneficial to improving the service life of the refractory material and reducing the smelting cost. DETAILED DESCRIPTION

[0031] The technical solutions of the application will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor fall within the protection scope of the application.

[0032] The application provides a vacuum smelting method of GH4169, comprising the following steps:

[0033] S1: holding molten steel: holding molten steel in a vacuum induction furnace, the molten steel including one or more of pure iron, metal nickel, SUS316, GH4080A and GH4169, and keeping the vacuum induction furnace in a state of being powered and heated and being vacuumized;

[0034] S2: raw material pretreatment: selecting GH4169 and nickel plate, pure iron, aluminum block, titanium plate return materials for rust removal treatment, and cutting the return materials to complete the pretreatment of raw materials;

[0035] S3: batching: according to the element types of GH4169 alloy and the steel grade composition and quality of the molten steel in step S1, accurate batching is performed, and the chemical composition of the GH4169 alloy includes:

[0036] C: ≤0.080%; Cr: 17.0%-21.0%; Ni: 50.0%-55.0%; Co: ≤1.0%; Mo: 2.80%-3.30%; Al: 0.30%-0.70%; Ti: 0.75%-1.15%; Nb: 4.75%-5.50%; the balance is iron and other unavoidable impurities;

[0037] S4: charging: under the premise of not damaging the vacuum of the vacuum induction furnace, according to the batching result of step S3, raw materials including one or more of the return materials of step S2 and high-purity graphite blocks, pure iron, metal chromium, metal nickel, metal molybdenum, metal niobium, metal aluminum, metal titanium plate, boron iron, phosphorus iron and nickel-magnesium alloy are charged from the top charging bin and side charging bin of the vacuum induction furnace, and the vacuum induction furnace is kept powered and heated and vacuumized during the charging process;

[0038] S5: alloy melting: the held molten steel melts the raw materials charged in step S4 into a metal liquid by physical heat conduction. After mixing, an alloy liquid is formed, and the raw materials are continuously heated by the vacuum induction furnace in a small to large step-up power mode to complete vacuum smelting.

[0039] Preferably, in step S2, the cutting conditions are that the return materials are cut to a size of less than or equal to 200mm x 200mm x 200mm.

[0040] Preferably, in step S3, the chemical composition of the GH4169 alloy includes:

[0041] C: 0.015%-0.060%; Cr: 17.0%-21.0%; Ni: 50.0%-55.0%; Co: ≤1.0%;

[0042] Mo: 2.80%-3.30%; Al: 0.30%-0.70%; Ti: 0.75%-1.15%; Nb: 5.00%-5.50%; balance iron and other inevitable impurities.

[0043] Preferably, the chemical composition of the GH4169 alloy comprises:

[0044] C: 0.012%-0.036%; Cr: 17.0%-19.0%; Ni: 52.0%-55.0%; Co: ≤1.0%;

[0045] Mo: 2.80%-3.15%; Al: 0.35%-0.65%; Ti: 0.75%-1.15%; Nb: 5.20%-5.50%; Fe: 16.0%-19.0%, balance other inevitable impurities.

[0046] Preferably, in the step S4, the sequence of charging is that the high melting point raw materials are preferentially added, and the raw materials are sequentially added into the vacuum induction furnace from large to small according to the size of the raw materials.

[0047] Preferably, in the step S5, the weight of the retained liquid steel is 15%-60% of the mass of the alloy liquid.

[0048] Preferably, the weight of the liquid steel is 20%-50% of the mass of the alloy liquid.

[0049] The application also provides a GH4169 alloy prepared by the above preparation method, and the GH4169 alloy comprises the following components:

[0050] Table 1 Chemical composition of GH4169 series products

[0051]

[0052] The application is described in more detail below by combining the type, composition and weight of the retained liquid steel with examples. These examples are only used to describe the preferred embodiments of the application and do not limit the scope of the application in any way.

[0053] Example 1:

[0054] S1: Retain an appropriate amount of liquid steel:

[0055] The furnace is charged with 305.031 kg of liquid pure iron.

[0056] Retained liquid pure iron for producing GH4169 series products

[0057] S2: Raw material pretreatment:

[0058] The nickel plate, aluminum block, titanium plate and the like required for smelting GH4169 series products are subjected to rust removal treatment. In addition, the nickel plate is subjected to sawing and shearing division, and the size is less than or equal to 200 mm x 200 mm x 200 mm.

[0059] S3: batching:

[0060] According to the composition and weight of the pure molten iron left in the upper furnace, combined with the composition control requirements of the GH4169 series products and the tapping amount of the present furnace, batching is performed, and the batching sheet is shown in Table 2. The liquid molten iron accounts for 20.21% of the total loading amount of the present furnace.

[0061] Table 2 Batching sheet of Example 1

[0062]

[0063] S4: charging:

[0064] Under the premise of not breaking the vacuum, according to the batching results of step 3, 44.913 kg of metallic molybdenum, 77.969 kg of metallic niobium, 0.488 kg of high-purity graphite block and 296.012 kg of metallic chromium are added from the top charging bin of the vacuum induction furnace. 756.559 kg of metallic nickel is added from the side charging bin. Other raw materials 8.617 kg of metallic aluminum, 15.886 kg of metallic titanium plate, 0.269 kg of boron iron and 3.551 kg of nickel-magnesium alloy are added from the top charging bin during the smelting and refining period. During the charging process, the high-melting-point metal molybdenum is preferentially added to the furnace. The vacuum induction furnace continues to be vacuumed during the charging period.

[0065] S5: alloy melting:

[0066] The vacuum degree of the vacuum induction furnace at the initial stage of charging is 15 Pa, which meets the technical requirements of smelting power-on. Under the condition of power-on, 44.913 kg of metallic molybdenum, 77.969 kg of metallic niobium, 0.488 kg of high-purity graphite block and 296.012 kg of metallic chromium are first added from the top charging bin of the vacuum induction furnace. 756.559 kg of metallic nickel is added from the side charging bin. The power-on power during the charging period is 150 KW, and the addition time of the first batch of materials is 30 minutes. After the first batch of materials is added, the heating power is increased to 400 KW, and after 60 minutes, the first batch of materials has been completely melted. Subsequently, the heating power is increased to 500 KW, and after heating for about 60 minutes, the temperature has risen to 1520℃, meeting the requirements of the smelting and refining period. Finally, according to the smelting curve requirements, other raw materials 8.617 kg of metallic aluminum, 15.886 kg of metallic titanium plate, 0.269 kg of boron iron and 3.551 kg of nickel-magnesium alloy are added from the top charging bin during the smelting and refining period.

[0067] The refining period lasts for about 240 minutes, and the composition of the molten steel meets the requirements of GH4169 series products through sampling analysis. The whole melting time of the furnace is 390 minutes, which is 150 minutes shorter than the melting time of 540 minutes of the cold-charged vacuum breaking method, and the time reduction ratio is 27.8%, which is more efficient than the vacuum hot charging method.

[0068] Example 2

[0069] Production of GH4169 series products by retaining liquid pure nickel water

[0070] S1: Retain an appropriate amount of molten steel:

[0071] 450.000 kg of liquid pure nickel water is retained in the furnace.

[0072] S2: Raw material preparation:

[0073] The pure iron, nickel plate, aluminum block, titanium plate and other materials required for melting GH4169 series products are subjected to rust removal treatment. In addition, the pure iron and nickel plate are sawn and cut into pieces with a size of less than or equal to 200mm x 200mm x 200mm.

[0074] S3: Precise batching:

[0075] According to the composition and weight of the retained pure nickel water in the furnace, combined with the composition control requirements of GH4169 series products and the tapping amount of the furnace, the batching is carried out, and the batching sheet is shown in Table 3. The liquid pure nickel water accounts for 29.82% of the total charging amount of the furnace.

[0076] Table 3 Batching sheet of Example 2

[0077] Raw material name Amount added, kg C Si P S Cr Ni Mo Nb Al Ti B Mg Fe Liquid state J-Ni 450.000 99.50 0.50 Pure iron 305.031 0.010 0.10 0.020 0.002 99.87 J-Ni 306.559 99.50 0.50 J-Cr 296.012 0.007 99.00 0.15 0.84 J-Mo 44.913 0.005 99.96 0.04 J-Nb 77.969 99.80 0.20 Graphite carbon 0.488 100 0.00 J-Al 8.617 99.90 0.10 J-Ti 15.886 0.020 99.76 0.22 Fe-B22C0.05 0.269 0.040 0.90 0.045 0.009 1.30 22.42 75.29 Ni-Mg 3.551 82.00 17.00 1.00 Batch weight and composition 1509.296 0.036 0.02 0.004 0.000 19.42 50.07 2.97 5.16 0.60 1.05 0.0040 0.0400 20.63

[0078] S4: Charging:

[0079] Under the premise of not breaking the vacuum, according to the batching results of step 3, 44.913 kg of molybdenum, 77.969 kg of niobium, 0.488 kg of high-purity graphite block and 296.012 kg of chromium are added from the top charging bin of the vacuum induction furnace. 306.559 kg of nickel and 305.031 kg of pure iron are added from the side charging bin. Other raw materials, 8.617 kg of aluminum, 15.886 kg of titanium plate, 0.269 kg of boron iron and 3.551 kg of nickel-magnesium alloy, are added from the top charging bin during the melting and refining period. During the charging process, high-melting-point molybdenum is preferentially added to the furnace. The vacuum induction furnace continues to be vacuumed during the charging period.

[0080] S5: Alloy melting:

[0081] The vacuum degree of the vacuum induction furnace at the initial stage of charging is 10 Pa, which meets the technical requirements of melting and power supply. Under the condition of power supply, 44.913 kg of metal molybdenum, 77.969 kg of metal niobium, 0.488 kg of high-purity graphite block and 296.012 kg of metal chromium are first added from the top charging bin of the vacuum induction furnace. 306.559 kg of metal nickel and 305.031 kg of pure iron are added from the side charging bin. The power supply power during charging is 150 KW, and the addition time of the first batch of materials is 25 minutes. After the first batch of materials is added, the heating power is increased to 400 KW, and after 50 minutes, the first batch of materials has been completely melted. Subsequently, the heating power is increased to 500 KW, and after heating for about 40 minutes, the temperature has risen to 1520℃, which meets the requirements of the smelting and refining period. Finally, according to the smelting curve requirements, 8.617 kg of metal aluminum, 15.886 kg of metal titanium plate, 0.269 kg of boron iron and 3.551 kg of nickel-magnesium alloy are added from the top charging bin during the smelting and refining period.

[0082] The refining period lasts for about 240 minutes, and after sampling analysis, the composition meets the requirements of GH4169 series products, and the steel is timely tapped. The whole smelting time of the furnace is 355 minutes, which is 185 minutes shorter than the smelting time of 540 minutes by the method of breaking vacuum and cold charging, and the time reduction ratio is 34.3%, and the vacuum hot charging method is more efficient.

[0083] Example 3

[0084] Production of GH4169 series products by retaining SUS316 liquid steel

[0085] S1: Retain an appropriate amount of molten steel:

[0086] 431.442 kg of SUS316 liquid steel is retained in the furnace.

[0087] S2: Preparation of raw materials:

[0088] The nickel plate, aluminum block, titanium plate and other materials required for smelting GH4169 series products are subjected to rust removal treatment. In addition, the nickel plate is cut and divided into pieces with a size of less than or equal to 200 mm x 200 mm x 200 mm.

[0089] S3: Accurate batching:

[0090] According to the composition and weight of the SUS316 liquid steel retained in the furnace, combined with the composition control requirements of GH4169 series products and the tapping amount of the furnace, the batching is carried out, and the batching list is shown in Table 4. The SUS316 liquid steel accounts for 28.58% of the total charging amount of the furnace.

[0091] Table 4 Batching list of Example 3

[0092] Raw material name Amount added, kg C Si P S Cr Ni Cu Mn Mo Nb Al Ti B Mg Fe Liquid state SUS316 431.442 0.060 0.55 0.035 0.003 17.00 10.00 0.50 1.00 2.00 68.85 J-Ni 713.178 99.50 0.50 J-Cr 221.918 0.007 99.00 0.15 0.84 J-Mo 36.279 0.005 99.96 0.04 J-Nb 77.967 99.80 0.20 Graphite carbon 0.266 100.000 0.00 J-Al 8.729 99.90 0.10 J-Ti 15.888 0.020 99.76 0.22 Fe-B22C0.05 0.269 0.040 0.9 0.045 0.009 1.30 22.42 75.29 Ni-Mg 3.552 82.00 17 1.00 Tap weight and composition 1509.487 0.036 0.16 0.010 0.0009 19.41 50.06 0.14 0.29 2.97 5.15 0.60 1.05 0.004 0.04 20.07

[0093] S4: Charging:

[0094] Without breaking the vacuum, 36.279 kg of metal molybdenum, 77.967 kg of metal niobium, 0.266 kg of high-purity graphite block and 221.918 kg of metal chromium were added from the top charging bin of the vacuum induction furnace according to the charging result of step 3. 713.178 kg of metal nickel was added from the side charging bin. Other raw materials 8.729 kg of metal aluminum, 15.888 kg of metal titanium plate, 0.269 kg of boron iron and 3.552 kg of nickel-magnesium alloy were added from the top charging bin during the smelting and refining period. The high-melting-point metal molybdenum was preferentially added to the furnace during the charging process. The vacuum induction furnace continued to be vacuumed during the charging period.

[0095] S5: Alloy melting:

[0096] The vacuum degree of the vacuum induction furnace at the beginning of charging was 12 Pa, meeting the technical requirements for smelting power-on. Under the condition of power-on, 36.279 kg of metal molybdenum, 77.967 kg of metal niobium, 0.266 kg of high-purity graphite block and 221.918 kg of metal chromium were first added from the top charging bin of the vacuum induction furnace. 713.178 kg of metal nickel was added from the side charging bin. The power during the charging period was 150 KW, and the addition time of the first batch of materials was 30 minutes. After the first batch of materials was added, the heating power was increased to 400 KW, and after 30 minutes, the first batch of materials had been completely melted. Subsequently, the heating power was increased to 500 KW, and after about 30 minutes, the temperature had risen to 1520℃, meeting the requirements of the smelting and refining period. Finally, other raw materials 8.729 kg of metal aluminum, 15.888 kg of metal titanium plate, 0.269 kg of boron iron and 3.552 kg of nickel-magnesium alloy were added from the top charging bin during the smelting and refining period according to the smelting curve requirements.

[0097] The refining period lasted for about 240 minutes, and after sampling analysis, the composition met the requirements of GH4169 series products and the steel was tapped in time. The entire smelting time of the furnace was 330 minutes, which was 210 minutes shorter than the smelting time of 540 minutes by the breaking-vacuum cold charging method, with a time reduction ratio of 38.9%, and the vacuum hot charging method was more efficient.

[0098] Example 4:

[0099] Leaving GH4080A liquid steel to produce GH4169 series products

[0100] S1: Leaving an appropriate amount of molten steel:

[0101] 555.242 kg of GH4080A liquid steel was left in the furnace.

[0102] S2: Raw material preparation:

[0103] The pure iron, nickel plate, aluminum block, titanium plate and other materials required for melting GH4169 series products are subjected to rust removal treatment. In addition, the nickel plate and pure iron are subjected to sawing and shearing division, and the size is less than or equal to 200 mm x 200 mm x 200 mm.

[0104] S3: Precise batching

[0105] According to the composition and weight of the GH4080A liquid steel retained in the upper furnace, combined with the composition control requirements of the GH4169 series products and the tapping amount of the present furnace, batching is performed, and the batching sheet is shown in Table 5. The GH4080A liquid steel accounts for 36.79% of the total charging amount of the present furnace.

[0106] Table 5 Batching sheet of Example 4

[0107] Raw material name Amount added, kg C Si P S Cr Ni Co Mo Nb Al Ti B Mg Fe Liquid state GH4080A 555.242 0.063 0.05 0.004 0.003 19.36 76.52 0.08 1.58 2.31 0.0050 0.00 Pure iron 307.335 0.010 0.1 0.02 0.002 99.87 J-Ni 329.548 99.50 0.50 J-Cr 187.429 0.007 99.00 0.15 0.84 J-Mo 44.912 0.005 99.96 0.04 J-Nb 77.969 99.80 0.20 Graphite carbon 0.149 100 0.00 J-Al 0 99.90 0.10 J-Ti 3.029 0.020 99.76 0.22 Fe-B22C0.05 0.145 0.040 0.9 0.045 0.009 1.30 22.4200 75.29 Ni-Mg 3.551 82.00 17.00 1.00 Batch weight and composition 1509309 0.036 0.04 0.006 0.0015 19.42 50.07 0.03 2.97 5.16 0.60 1.05 0.0040 0.0400 20.57

[0108] S4: Charging

[0109] Under the premise of not breaking the vacuum, according to the batching results of step 3, 44.912 kg of metallic molybdenum, 77.969 kg of metallic niobium, 0.149 kg of high-purity graphite block and 187.429 kg of metallic chromium are added from the top charging bin of the vacuum induction furnace. 329.548 kg of metallic nickel and 307.335 kg of pure iron are added from the side charging bin. Other raw materials 3.029 kg of metallic titanium plate, 0.145 kg of boron iron and 3.551 kg of nickel-magnesium alloy are added from the top charging bin during the melting and refining period. During the charging process, the high-melting-point metal molybdenum is preferentially added to the furnace. The vacuum induction furnace continues to be vacuumed during the charging period.

[0110] S5: Alloy melting

[0111] The vacuum degree of the vacuum induction furnace at the initial stage of charging is 10 Pa, which meets the technical requirements of melting power-on. Under the condition of power-on, 44.912 kg of metallic molybdenum, 77.969 kg of metallic niobium, 0.149 kg of high-purity graphite block and 187.429 kg of metallic chromium are first added from the top charging bin of the vacuum induction furnace. 329.548 kg of metallic nickel and 307.335 kg of pure iron are added from the side charging bin. The power-on power during the charging period is 150 KW, and the addition time of the first batch of materials is 20 minutes. After the first batch of materials is added, the heating power is increased to 400 KW, and after 20 minutes, the first batch of materials has been completely melted. Subsequently, the heating power is increased to 500 KW, and after about 20 minutes, the temperature has risen to 1520℃, which meets the requirements of the melting and refining period. Finally, according to the melting curve requirements, other raw materials 3.029 kg of metallic titanium plate, 0.145 kg of boron iron and 3.551 kg of nickel-magnesium alloy are added from the top charging bin during the melting and refining period.

[0112] The refining period lasts for about 240 minutes, and the composition of the GH4169 series product is analyzed by sampling and meets the composition requirements of the GH4169 series product and the molten steel is tapped in time. The entire melting time of the furnace is 300 minutes, which is 240 minutes shorter than the melting time of 540 minutes by the cold-state charging method without breaking the vacuum, and the time reduction ratio is 44.4%, and the vacuum hot charging method is more efficient.

[0113] Example 5

[0114] Production of GH4169 series products from the GH4169 liquid molten steel

[0115] S1: Leave a proper amount of molten steel:

[0116] 755.000 kg of GH4169 liquid molten steel is left in the furnace.

[0117] S2: Raw material preparation:

[0118] The pure iron, nickel plate, aluminum block, titanium plate, etc. required for melting the GH4169 series product are subjected to rust removal treatment. In addition, the nickel plate and pure iron are sawn and cut into pieces with a size of less than or equal to 200mm x 200mm x 200mm.

[0119] S3: Precise batching:

[0120] According to the composition and weight of the GH4169 liquid molten steel left in the furnace, combined with the composition control requirements of the GH4169 series product and the tapping amount of the furnace, the batching is carried out, and the batching sheet is shown in Table 6, and the GH4169 liquid molten steel accounts for 50.02% of the total charging amount of the furnace.

[0121] Table 6 Batching sheet of Example 5

[0122] Raw material name Amount added, kg C Si P S Cr Ni Mo Nb Al Ti B Mg Fe Liquid state GH4169 755.000 0.028 0.06 0.009 0.002 18.51 53.31 2.97 5.18 0.53 0.99 0.0038 0.0029 18.29 Pure iron 168.979 0.010 0.10 0.020 0.002 99.87 J-Ni 352.143 99.50 0.50 J-Cr 154.846 0.007 99.00 0.15 0.84 J-Mo 22.478 0.005 99.96 0.04 J-Nb 38.781 99.80 0.20 Graphite carbon 0.300 100 0.00 J-Al 4.825 99.90 0.10 J-Ti 8.393 0.020 99.76 0.22 Fe-B22C0.05 0.141 0.040 0.90 0.045 0.009 1.30 22.42 75.29 Ni-Mg 3.423 82.00 17.00 1.00 Batch weight and composition 1509311 0.036 0.04 0.007 0.001 19.42 50.07 2.97 5.16 0.60 1.05 0.0040 0.0400 20.55

[0123] S4: Charging:

[0124] Under the premise of not breaking the vacuum, according to the batching results of step 3, 22.478 kg of metallic molybdenum, 38.781 kg of metallic niobium, 0.300 kg of high-purity graphite block and 154.846 kg of metallic chromium are added from the top charging bin of the vacuum induction furnace. 352.143 kg of metallic nickel and 168.979 kg of pure iron are added from the side charging bin. Other raw materials such as 8.393 kg of metallic titanium plate, 0.141 kg of boron iron and 3.423 kg of nickel-magnesium alloy are added from the top charging bin during the melting and refining period. During the charging process, high-melting-point metal molybdenum is preferentially added to the furnace. The vacuum induction furnace continues to be vacuumed during the charging period.

[0125] S5: Alloy melting:

[0126] The vacuum degree of the vacuum induction furnace at the initial stage of charging is 8 Pa, satisfying the technical requirements of melting and power supply. Under the condition of power supply, 22.478 kg of metallic molybdenum, 38.781 kg of metallic niobium, 0.300 kg of high-purity graphite block and 154.846 kg of metallic chromium are first added from the top charging bin of the vacuum induction furnace. 352.143 kg of metallic nickel and 168.979 kg of pure iron are added from the side charging bin. The power supply power during the charging period is 150 KW, and the addition time of the first batch of materials is 10 minutes. After the first batch of materials is added, the heating power is increased to 400 KW, and after 5 minutes, the first batch of materials has been completely melted. Subsequently, the heating power is increased to 500 KW, and after about 5 minutes, the temperature has been increased to 1520 DEG C, satisfying the requirements of the smelting and refining period. Finally, according to the requirements of the smelting curve, 8.393 kg of metallic titanium plate, 0.141 kg of boron iron and 3.423 kg of nickel-magnesium alloy are added from the top charging bin during the smelting and refining period.

[0127] The refining period lasts for about 240 minutes, and after sampling analysis, the composition satisfies the requirements of GH4169 series products and the steel is discharged in time. The whole smelting time of the furnace is 260 minutes, which is shortened by 280 minutes compared with the smelting time of 540 minutes by the broken vacuum cold charging method, and the time reduction ratio is 51.9%, and the vacuum hot charging method is more efficient.

[0128] In summary, the vacuum hot charging technology adopted by the present application, in the process of smelting GH4169 series products in a vacuum induction furnace, since the vacuum state of the furnace is not destroyed, compared with the broken vacuum charging method, the time for vacuumizing the smelting cavity is saved, and during the charging process, power is directly supplied, which also reduces the heat loss of refractory materials and high-temperature molten steel, which is beneficial to improve the thermal efficiency and shorten the smelting time. Since the retained hot molten steel brings a large amount of physical heat, a relatively stable metal molten pool can be quickly formed during the smelting process, which accelerates the melting speed of solid furnace charges, and is also beneficial to reduce the smelting time, reduce the power consumption per ton of steel, and improve the labor productivity.

[0129] In addition, due to the retained liquid molten steel, which can flow and fill in the gaps of the furnace charges, the lower part of the furnace charges is compacted, the loose density of the furnace charges in the vacuum induction furnace is improved, the "bridging" phenomenon during the smelting process can be avoided, which is beneficial to the smooth progress of the smelting process and reduces the smelting time. In addition, the refractory materials of the vacuum hot charging method are always at a relatively high temperature, and the temperature drop is significantly reduced, which reduces the tendency of cracks in the refractory materials due to rapid cooling and heating, which is beneficial to improve the service life of the refractory materials and reduce the smelting cost.

[0130] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present disclosure.

Claims

1. A vacuum melting method of GH4169, characterized in that, The method comprises the following steps: S1: holding molten steel in a vacuum induction furnace, the molten steel comprising one or more of pure iron, metal nickel, SUS316, GH4080A and GH4169, and keeping the vacuum induction furnace in a state of being powered and vacuumized; S2: raw material pretreatment: rust removal treatment is performed on returned materials of GH4169 and nickel plate, pure iron, aluminum block and titanium plate, and the returned materials are cut to complete the pretreatment of the raw materials; S3: batching: accurate batching is performed according to the types of elements of the GH4169 alloy and the steel grade composition and quality of the molten steel in the step S1, the chemical composition of the GH4169 alloy comprising: C: ≤0.080%; Cr: 17.0%-21.0%; Ni: 50.0%-55.0%; Co: ≤1.0%; Mo: 2.80%-3.30%; Al: 0.30%-0.70%; Ti: 0.75%-1.15%; Nb: 4.75%-5.50%; the balance being iron and other inevitable impurities; S4: charging: under the premise of not damaging the vacuum of the vacuum induction furnace, raw materials are charged from the top charging bin and the side charging bin of the vacuum induction furnace according to the batching result of the step S3, the raw materials comprising one or more of the returned materials of the step S2 and high-purity graphite blocks, pure iron, metal chromium, metal nickel, metal molybdenum, metal niobium, metal aluminum, metal titanium plate, boron iron, phosphorus iron and nickel-magnesium alloy, and the vacuum induction furnace is kept powered and vacuumized during the charging process; S5: alloy melting: the raw materials charged in the step S4 are melted into a metal liquid by physical heat conduction in a manner that the held molten steel mixes with the raw materials to form an alloy liquid, and the raw materials are continuously heated by the vacuum induction furnace in a small-to-large stepwise power increasing manner to complete vacuum smelting; In the step S5, the weight of the held molten steel is 15%-60% of the mass of the alloy liquid; In the step S4, the charging sequence is: high-melting-point raw materials are preferentially added, and the raw materials are sequentially added to the vacuum induction furnace in a size order from large to small.

2. The vacuum melting method of GH4169 according to claim 1, characterized in that, In the step S2, the cutting condition is that the returned materials are cut to a size of less than or equal to 200mm×200mm×200mm.

3. The vacuum melting method of GH4169 according to claim 1, characterized in that, In the step S3, the chemical composition of the GH4169 alloy comprises: C: 0.015%-0.060%; Cr: 17.0%-21.0%; Ni: 50.0%-55.0%; Co: ≤1.0%; Mo: 2.80%-3.30%; Al: 0.30%-0.70%; Ti: 0.75%-1.15%; Nb: 5.00%-5.50%; the balance being iron and other inevitable impurities.

4. The vacuum melting method of GH4169 according to claim 3, characterized in that, The chemical composition of the GH4169 alloy comprises: C: 0.012% - 0.036%; Cr: 17.0% - 19.0%; Ni: 52.0% - 55.0%; Co: < 1.0%; Mo: 2.80% - 3.15%; Al: 0.35% - 0.65%; Ti: 0.75% - 1.15%; Nb: 5.20% - 5.50%; Fe: 16.0% - 19.0%, the balance being other unavoidable impurities.

5. The vacuum melting method of GH4169 according to claim 1, wherein, The weight of the molten steel is 20% - 50% of the mass of the alloy liquid.

6. A GH4169 alloy characterized by, The GH4169 alloy is prepared by the method of any one of claims 1 - 5.

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