A method of forging a GH2901 alloy bar

Abstract

The application provides a GH2901 alloy bar forging method, which comprises the following steps: S1. weighing high-purity metals Cr, Ni, Mo, Al, Ti and graphite C, and adding the above raw materials into a smelting furnace to perform smelting, refining, pouring, and obtaining an electrode bar, and self-consumption remelting the electrode bar into a self-consumption ingot; S2. placing the self-consumption ingot in a heating furnace to perform homogenization high-temperature diffusion; S3. performing circumferential surface rolling and preheating of the self-consumption ingot; S4. axially forging the self-consumption ingot to obtain an alloy blank; S5. performing radial forging heat deformation and reheating of the alloy blank for 4-6 times to obtain an alloy round bar; S6. performing bright turning treatment of the alloy round bar; and S7. performing ultrasonic detection of the alloy round bar. The application reasonably optimizes the alloy component range; reduces element segregation of the self-consumption ingot through homogenization diffusion treatment; eliminates part of the as-cast structure through axial deformation; and forms fine and uniform grain structure through reasonable distribution of forging deformation rate and heating temperature.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high-temperature alloy, in particular to a GH2901 alloy bar forging method. BACKGROUND

[0002] The GH2901 alloy is a Fe-Ni-Cr-based deformed high-temperature alloy with Cr and Mo as solid solution strengthening elements and 3% Ti as aging strengthening element; the alloy is aged with [Ni3(Ti, Al)] phase, and trace Al element inhibits the conversion of γ' to η-Ni3Ti phase; the alloy has high yield strength and endurance strength below 650 DEG C, good oxidation resistance below 760 DEG C, stable long-term use structure, and can be used for rotating parts and fasteners of aero-engine and ground gas turbine; the existing forged bar has uneven grain size. SUMMARY

[0003] The present application aims to overcome the deficiencies in the prior art, and provides a GH2901 alloy bar forging method, which uses Φ508mm consumable ingot as raw material, and controls the grain size of the forged bar to be small and uniform through homogenization diffusion treatment, multi-fire step temperature heating and multi-fire matching forging deformation rate.

[0004] The technical scheme adopted by the present application is:

[0005] A GH2901 alloy bar forging method, wherein: by weight, the following components are included:

[0006] S1. The nickel-based high-temperature alloy cake includes the following components by mass fraction: C 0.02-0.04%, Cr 12.0-13.0%, Ni 42.0-43.0%, Mo 5.5-6.0%, Al 0.15-0.30%, Ti 2.90-3.05%, and the balance is inevitable impurity elements, the total of the above is 100%, high-purity metals Cr, Ni, Mo, Al, Ti and graphite C are weighed and added to a smelting furnace for smelting and vacuumizing, the vacuum degree is controlled to be less than or equal to 15Pa, after the ingredients are completely melted, the vacuum degree is controlled to be less than or equal to 5Pa for 1-10h of refining, then pouring to obtain an electrode rod, and welding a dummy electrode on the head of the electrode rod and placing it in a vacuum smelting furnace for consumable remelting into a consumable ingot;

[0007] S2. The consumable ingot is placed in a heating furnace for homogenization high-temperature diffusion;

[0008] The purpose of homogenization high-temperature diffusion is to reduce the dendritic segregation coefficient of Cr, Mo and Ti elements in the ingot structure and improve the diameter interval of the ingot internal as-cast.

[0009] S3. The consumable ingot after homogenization high-temperature diffusion in step S2 is subjected to circumferential surface roll grinding, and the roll-ground consumable ingot is preheated through a heating furnace;

[0010] The preheating purpose is to sufficiently heat the inside and outside of the consumable ingot, so that the material temperature of the consumable ingot is in the optimal recrystallization temperature range in the subsequent forging hot deformation process.

[0011] S4. The preheated consumable ingot is axially forged by a free forging press to deform the consumable ingot in the axial direction, so as to eliminate part of the as-cast dendritic structure and simultaneously increase the radial cross-sectional area, to obtain an alloy blank;

[0012] S5. The alloy blank after step S4 is subjected to radial forging hot deformation and reheating for 4-6 heating times to obtain an alloy round bar;

[0013] S6. The alloy round bar is subjected to bright turning treatment;

[0014] S7. The alloy round bar is subjected to 100% contact method ultrasonic detection, and is stored after passing the detection.

[0015] Preferably, the GH2901 alloy bar forging method, wherein: the vacuum degree in step S1 is controlled to be ≤1 MPa.

[0016] Preferably, the GH2901 alloy bar forging method, wherein: the temperature of the homogenization high-temperature diffusion in step S2 is 1200℃±10℃, and the holding time is 48-50h.

[0017] Preferably, the GH2901 alloy bar forging method, wherein: the preheating temperature in step S3 is 1100℃±10℃, and the holding time is 7-10h.

[0018] Preferably, the GH2901 alloy bar forging method, wherein: the forging press in step S4 is axially forged at a deformation speed of 15-20mm / s, and the length ratio of the alloy blank to the consumable ingot is 62-70:100.

[0019] Preferably, the GH2901 alloy bar forging method, wherein: in step S5, the average deformation rate of 1-3 heating times of free forging is controlled to be 35%±2%, the heating temperature is controlled to be 1100℃±10℃, and the holding time is 30-90min, the average deformation rate of 4-6 heating times of free forging is controlled to decrease by 3-5% each time, the heating temperature is controlled to be 1020℃±10℃, and the holding time is 30-90min.

[0020] The radial forging hot deformation process can be divided into two stages: in the first stage, the average deformation rate is 35%±2% in the first 1-3 heating times, and the heating temperature is 1100℃±10℃, which aims to completely convert the residual as-cast group into coarse equiaxed crystal organization; in the second stage, the average deformation rate is decreased by 3-5% per heating time in the last 4-ultimate heating times, and the heating temperature is 1020℃±10℃, which aims to complete the dynamic recrystallization of the alloy material while uniformly forging hot deformation, so as to form a uniform and fine grain organization.

[0021] Preferably, the GH2901 alloy bar forging method, wherein: the depth of the step S6 is controlled to be 5-10% of the diameter of the alloy round bar to eliminate the edge oxidation layer, and the surface roughness of the alloy round bar is controlled to be ≤1.6μm.

[0022] Advantages of the present application:

[0023] (1) The GH2901 alloy bar forging method of the present application reasonably optimizes the alloy composition range; reduces the element segregation of the consumable ingot through homogenization diffusion treatment; eliminates part of the as-cast organization through axial deformation; forms a fine and uniform grain organization through reasonable allocation of forging deformation rate and heating temperature; the uniform grain organization provides more accurate sound wave reflection feedback for ultrasonic testing, which is beneficial to the discovery and elimination of defects. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 It is a grain size test graph of Example 1 of the present application.

[0025] Figure 2 It is a grain size test graph of Example 2 of the present application. DETAILED DESCRIPTION

[0026] The present application will be further described below in combination with specific drawings and examples.

[0027] Example 1

[0028] A GH2901 alloy bar forging method, characterized in that: the components include the following components by weight:

[0029] S1. The component content of the nickel-based high-temperature alloy cake material is shown in Table 1, high-purity metals Cr, Ni, Mo, Al, Ti, and graphite C are weighed, and the above raw materials are added to a smelting furnace for smelting and vacuumizing, the vacuum degree is controlled to be ≤15Pa, after the ingredients are completely melted, the vacuum degree is controlled to be ≤5Pa for refining for 6h, then pouring to obtain an electrode rod, and welding a dummy electrode on the head of the electrode rod and putting it into a vacuum smelting furnace for consumable remelting into a consumable ingot, and the vacuum degree of the consumable remelting is controlled to be ≤1MPa;

[0030] S2. The consumable ingot is placed in a heating furnace for homogenization high-temperature diffusion, the temperature of the homogenization high-temperature diffusion is 1210℃, and the holding time is 48.5h;

[0031] S3. The consumable ingot after the homogenization high-temperature diffusion in step S2 is subjected to circumferential surface roll grinding, and the consumable ingot after the roll grinding is preheated through a heating furnace, the preheating temperature is 1100℃, and the holding time is 7h;

[0032] S4. The preheated consumable ingot is forged along the axial direction by a free forging press to deform the consumable ingot in the axial direction, the forging press is used to forge at a deformation linear velocity of 18.5mm / s in the axial direction, the length ratio of the alloy blank and the consumable ingot is 68:100, and an alloy blank is obtained;

[0033] S5. The alloy blank after the treatment in step S4 is subjected to radial forging heat deformation and reheating for 5 heating times, the average deformation rate is controlled to be 35% in free forging for 1-3 heating times, the heating temperature is controlled to be 1100℃, and the holding time is 60min, the average deformation rate is controlled to be decreased by 3% per heating time in free forging for 4-5 heating times, the heating temperature is controlled to be 1020℃, and the holding time is 60min, and an alloy round bar is obtained;

[0034] S6. The alloy round bar is subjected to bright turning treatment, the bright turning depth accounts for 8% of the radial direction of the alloy round bar, and the surface roughness of the alloy round bar is controlled to be ≤1.6μm;

[0035] S7. The alloy round bar is subjected to contact method 100% ultrasonic detection, and is stored after passing the detection.

[0036] Example 2

[0037] A GH2901 alloy bar forging method, wherein: the components include the following components by weight parts:

[0038] S1. The component content of the nickel-based high-temperature alloy cake material is shown in Table 1, high-purity metals Cr, Ni, Mo, Al, Ti, and graphite C are weighed, the above raw materials are added into a smelting furnace for smelting and vacuumizing, the vacuum degree is controlled to be ≤15Pa, after the ingredients are completely melted, the vacuum degree is controlled to be ≤5Pa for refining for 6h, then pouring is performed to obtain an electrode rod, the electrode rod head is welded with a dummy electrode, and the electrode rod is placed into a vacuum smelting furnace for consumable remelting into a consumable ingot, and the consumable remelting is controlled at a vacuum degree of ≤1MPa;

[0039] S2. The consumable ingot is placed in a heating furnace for homogenization high-temperature diffusion, the temperature of the homogenization high-temperature diffusion is 1210℃, and the holding time is 50h;

[0040] S3. The consumable ingot after homogenization and high temperature diffusion in step S2 is subjected to circumferential surface roll grinding, and the roll-ground consumable ingot is preheated through a heating furnace, the preheating temperature being 1100℃, and the holding time being 8h;

[0041] S4. The preheated consumable ingot is axially forged by a free forging press to make the consumable ingot axially deform, the forging press is forged at a deformation linear velocity of 20mm / s in the axial direction, the length ratio of the alloy blank and the consumable ingot being 66:100, to obtain an alloy blank;

[0042] S5. The alloy blank after step S4 is subjected to radial forging heat deformation and reheating for 6 times, the average deformation rate being controlled to be 35% in the free forging for 1-3 times, the heating temperature being controlled to be 1100℃, and the holding time being 60min, the average deformation rate being controlled to be decreased by 3% per time in the free forging for 4-6 times, the heating temperature being controlled to be 1020℃, and the holding time being 60min, to obtain an alloy round bar;

[0043] S6. The alloy round bar is subjected to bright turning treatment, the bright turning depth being controlled to be 5% of the diameter of the alloy round bar, and the surface roughness of the alloy round bar being controlled to be ≤1.6μm;

[0044] S7. The alloy round bar is subjected to 100% contact ultrasonic detection, and is stored after being qualified.

[0045] The component content of the nickel-based high-temperature alloy disc material of examples 1-2 is shown in table 1

[0046] Table 1 Element composition wt% of examples 1-2

[0047]

[0048]

[0049] Test:

[0050] 1. Grain size test: the bright turned bars of examples 1-2 with diameters of Φ250mm and Φ200mm respectively, the grain sizes are 7 and 7.5 respectively, see Figure 1 .

[0051] 2. Ultrasonic detection results

[0052] The bars of examples 1-2 are detected according to GB / T 4162 equivalent flat bottom hole Ф1.2mm and are qualified.

[0053] 3. Mechanical properties

[0054] All the mechanical property samples are heat treated: 1090℃*2h water cooling + 775℃*2h air cooling + 712℃*24h air cooling

[0055] 3.1 Room temperature tensile properties are shown in table 2.

[0056] Table 2

[0057]

[0058] 3.2 575℃ tensile properties as shown in Table 3.

[0059] Table 3

[0060]

[0061] 3.2 575℃ creep properties as shown in Table 4.

[0062] Table 4

[0063]

[0064] From Tables 2-4, it can be seen that the GH2901 alloy bar forging method prepared by the present application meets the common industry standards, and has good room temperature tensile properties, 575℃ tensile properties and 575℃ creep properties, and is very competitive in the market.

[0065] Finally, it should be noted that the above specific embodiments are merely used to illustrate the technical solutions of the present application and not to limit the present application. Although the present application has been described in detail with reference to the examples, it should be understood by those skilled in the art that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, and all should be covered in the scope of the claims of the present application.

Claims

1. A method of forging a GH2901 alloy bar, characterized by: By weight parts, including the following components: S1. By mass fraction, the nickel-based superalloy cake material includes the following components: C 0.02-0.04%, Cr 12.0-13.0%, Ni 42.0-43.0%, Mo 5.5-6.0%, Al 0.15-0.30%, Ti 2.90-3.05, the rest is inevitable impurity elements, the total of the above is 100%, high-purity metals Cr, metal Ni, metal Mo, metal Al, metal Ti, graphite C are weighed, and the raw materials are added to a smelting furnace for smelting and vacuumizing, the vacuum degree is controlled to be less than or equal to 15 Pa, after the ingredients are completely melted, the vacuum degree is controlled to be less than or equal to 5 Pa for refining for 1-10 h, then pouring, obtaining an electrode stick, and welding a dummy electrode on the head of the electrode stick and putting it into a vacuum smelting furnace for consumable remelting into a consumable ingot; S2. The consumable ingot is placed in a heating furnace for homogenization high-temperature diffusion; S3. The consumable ingot after homogenization high-temperature diffusion in step S2 is circumferential surface roll ground, and the roll-ground consumable ingot is preheated through a heating furnace; S4. The preheated consumable ingot is axially forged by a free forging press to deform the consumable ingot axially, obtaining an alloy billet; S5. The alloy billet after step S4 is processed for radial forging heat deformation and reheating for 4-6 heats, obtaining an alloy round bar; 1-3 heats of free forging control the average deformation rate to be 35%±2%, the heating temperature is controlled to be 1100℃±10℃, and the holding time is 30-90 min, 4-6 heats of free forging control the average deformation rate to decrease by 3-5% per heat, the heating temperature is controlled to be 1020℃±10℃, and the holding time is 30-90 min; S6. The alloy round bar is subjected to bright turning treatment; S7. The alloy round bar is subjected to contact method 100% ultrasonic detection, and is stored after passing the detection; The temperature of step S2 homogenization high-temperature diffusion is 1200℃±10℃, and the holding time is 48-50 h; In step S4, the forging press is forged along the axial direction at a deformation line speed of 15-20 mm / s, and the length ratio of the alloy billet to the consumable ingot is 62-70:

100.

2. The GH2901 alloy bar forging method of claim 1, characterized by: In step S1, the vacuum degree of consumable remelting is controlled to be less than or equal to 1 MPa.

3. The GH2901 alloy bar forging method of claim 1, characterized by: In step S3, the preheating temperature is 1100℃±10℃, and the holding time is 7-10 h.

4. The GH2901 alloy bar forging method of claim 1, characterized by: In step S6, the bright turning depth accounts for 5-10% of the radial direction of the alloy round bar, and the surface roughness of the alloy round bar is controlled to be less than or equal to 1.6 μm.

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