25Cr2MoVA thin plate for airplane braking and preparation method of 25Cr2MoVA thin plate

Abstract

The invention relates to a 25Cr2MoVA thin plate, in particular to a 25Cr2MoVA thin plate for airplane braking and a preparation method of the 25Cr2MoVA thin plate. The steel comprises the following chemical components in percentage by mass: 0.25 to 0.30 percent of C, 0.10 to 0.40 percent of S i, 0.40 to 0.70 percent of Mn, 1.50 to 1.80 percent of Cr, 0.25 to 0.35 percent of Mo, 0.15 to 0.30 percent of V, 0.03 to 0.05 percent of N i, 0.007 to 0.011 percent of A l, less than or equal to 0.015 percent of P, less than or equal to 0.005 percent of S and the balance of Fe. According to the 25Cr2MoVA thin plate for airplane braking, the content of carbon is properly increased, and the processes of electric arc furnace + LF + VD smelting, electroslag remelting, forging, hot rolling and solution annealing are adopted, so that the content of harmful elements P and S is obviously reduced; compared with an existing 25Cr2MoVA thin plate, the tensile strength, the yield strength and the grain size are all improved, and non-metallic inclusions are obviously reduced.

Description

Technical Field

[0001] The present invention relates to 25Cr2MoVA thin plates, and particularly to a 25Cr2MoVA thin plate for aircraft braking and a preparation method thereof. Background Art

[0002] 25Cr2MoVA is a medium-carbon heat-resistant steel widely used in the aerospace, petrochemical, machinery manufacturing, and automotive industries. It has good strength, toughness, and wear resistance. Especially in the aviation field, due to its high strength and excellent wear resistance, 25Cr2MoVA has become an ideal brake pad material in aircraft braking systems.

[0003] However, for 25Cr2MoVA thin plates, their technical indicators have strict requirements for hardness and strength levels. In particular, it is necessary to achieve a good match between strength and hardness, that is, high strength and low annealing hardness. Traditional composition designs have difficulties in achieving such good comprehensive mechanical properties, and at the same time, the existing production process guidance effects are also limited, making it difficult to meet the matching requirements of hardness and strength. Summary of the Invention

[0004] The purpose of the present invention is to solve the technical problem of the mismatch between the hardness and strength of existing 25Cr2MoVA thin plates, and to provide a 25Cr2MoVA thin plate for aircraft braking and a preparation method thereof.

[0005] To solve the above technical problems, the technical solution provided by the present invention is as follows:

[0006] A 25Cr2MoVA thin plate for aircraft braking, in terms of mass percentage, its chemical composition includes:

[0007] C: 0.25 - 0.30%, Si: 0.10 - 0.40%, Mn: 0.40 - 0.70%, Cr: 1.50 - 1.80%, Mo: 0.25 - 0.35%, V: 0.15 - 0.30%, Ni: 0.03 - 0.05%, Al: 0.007 - 0.011%, P ≤ 0.015%, S ≤ 0.005%, and the balance is Fe.

[0008] Further, in terms of mass percentage, its chemical composition includes:

[0009] C: 0.29 - 0.30%, Si: 0.10 - 0.20%, Mn: 0.40 - 0.70%, Cr: 1.50 - 1.80%, Mo: 0.25 - 0.35%, V: 0.15 - 0.30%, Ni: 0.03 - 0.05%, Al: 0.007 - 0.011%, P ≤ 0.015%, S ≤ 0.005%, and the balance is Fe.

[0010] A preparation method of 25Cr2MoVA thin plate for aircraft actuation, comprising the following steps:

[0011] S1. Prepare the furnace charge, melt it through an electric arc furnace + LF + VD, and obtain an alloy ingot that meets the chemical composition after cooling;

[0012] S2. Remove the defects on the surface of the alloy ingot, and perform electroslag remelting on the alloy ingot to obtain an electroslag ingot;

[0013] S3. Remove the defects on the surface of the electroslag ingot, heat the electroslag ingot to 1200 °C and hold for 6 - 10 h;

[0014] After heat preservation, forge the electroslag ingot with a deformation amount of 20% - 30%, and the deformation amount increases slowly with an increasing rate;

[0015] The starting forging temperature is ≥1100 °C, and the final forging temperature is ≥800 °C; after forging, air cool to obtain a forging blank;

[0016] S4. Grind the forging blank to remove the scale on the surface of the forging blank; heat the forging blank to 1150 - 1200 °C and hold for 2 - 3 h;

[0017] After heat preservation, perform hot rolling on the forging blank, the starting rolling temperature is ≥1100 °C, and the final rolling temperature is ≥900 °C;

[0018] After hot rolling, air cool to obtain a hot - rolled thin plate;

[0019] S5. Heat the hot - rolled thin plate to 660 °C - 720 °C, and perform annealing treatment on the hot - rolled thin plate, and the annealing treatment duration is 60 - 240 min;

[0020] After annealing, complete the preparation of the 25Cr2MoVA thin plate for aircraft actuation.

[0021] Furthermore, in step S1, the furnace charge consists of carbon steel, CrMo scrap steel, and nickel - containing scrap steel.

[0022] Furthermore, in step S2, the specific steps for performing electroslag remelting on the alloy ingot are as follows:

[0023] Load the alloy ingot as a consumable electrode into the electroslag remelting furnace;

[0024] Select NEU - E50F as the electroslag material, place it at the bottom of the mold, and at the same time, set the remelting rate of electroslag remelting to 6.0 kg / min, the remelting power to 450 KW, and the swing parameter to 0.35 - 0.40;

[0025] Start the electroslag remelting furnace, the consumable electrode melts to form droplets and enters the mold, and after being cooled in the mold for 2 h, demold to obtain a preliminary electroslag ingot;

[0026] After demoulding, the preliminary electroslag ingot is heated to 650°C - 700°C and held for 15 hours.

[0027] After the holding is completed, it is cooled in the furnace. When the temperature of the preliminary electroslag ingot drops to 500°C, it is taken out of the furnace and air-cooled to obtain the electroslag ingot.

[0028] Further, step S3 is specifically as follows:

[0029] Remove the defects on the surface of the electroslag ingot.

[0030] Place the electroslag ingot in an electric furnace and heat the electroslag ingot at a heating rate not greater than 100°C / h.

[0031] After the heating temperature reaches 1200°C, hold the electroslag ingot for 6 - 10 hours.

[0032] After the holding is completed, forge the electroslag ingot with a deformation amount of 20% - 30%. The rate is gradually increased. The starting forging temperature ≥ 1100°C and the final forging temperature ≥ 800°C.

[0033] After forging is completed, air-cool to obtain the forged billet.

[0034] Further, step S4 is specifically as follows:

[0035] Place the forged billet in an electric furnace and heat it at a heating temperature of 1150 - 1200°C for 5 hours.

[0036] After the heating is completed, hold for 2 - 3 hours and perform hot rolling on the forged billet. The starting rolling temperature ≥ 1050°C and the final rolling temperature ≥ 800°C.

[0037] After hot rolling is completed, air-cool to obtain the hot-rolled thin plate.

[0038] Further, step S5 is specifically as follows:

[0039] Load the hot-rolled thin plate into the furnace cavity of the electric furnace at room temperature and place charcoal on both sides in the furnace cavity.

[0040] Heat the hot-rolled thin plate by raising the temperature of the electric furnace to 660°C - 720°C, and the heating duration is 60 - 240 minutes.

[0041] After the heating is completed, cool it in the furnace. When the temperature of the electric furnace drops to 300°C, take it out of the furnace and air-cool to complete the preparation of the 25Cr2MoVA thin plate for aircraft use and obtain the 25Cr2MoVA thin plate for aircraft use.

[0042] Further, the thickness of the 25Cr2MoVA thin plate for aircraft use is 3.0 - 9.0 mm.

[0043] Furthermore, the tensile strength of the 25Cr2MoVA thin plate for aircraft actuation is ≥1080 MPa, the yield strength is ≥1000 MPa, the elongation after fracture is ≥12%, the reduction of area is ≥55%, the impact energy absorption is ≥63 J, the Brinell hardness is ≤241, the grain size is ≥8.0 grade, the non-metallic inclusions are ≤0.5 grade, and the single-sided decarburized layer is ≤2.5%.

[0044] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0045] 1. The 25Cr2MoVA thin plate for aircraft actuation provided by the present invention and its preparation method. By appropriately increasing the carbon content and using the processes of electric arc furnace + LF + VD melting, electroslag remelting, forging, hot rolling and solution annealing to prepare the 25Cr2MoVA thin plate for aircraft actuation, the contents of harmful elements P and S are significantly reduced. Moreover, for the 25Cr2MoVA thin plate for aircraft actuation with the same specifications, compared with the existing 25Cr2MoVA thin plate, while maintaining a relatively low hardness level, the tensile strength, yield strength and grain size are all significantly improved, so that the matching degree of hardness and strength meets the requirements.

[0046] 2. The 25Cr2MoVA thin plate for aircraft actuation provided by the present invention and its preparation method. The tensile strength of the 25Cr2MoVA thin plate for aircraft actuation prepared according to the chemical composition of the present invention and using the processes of electric arc furnace + LF + VD melting, electroslag remelting, forging, hot rolling and solution annealing is ≥1080 MPa, the yield strength is ≥1000 MPa, the elongation after fracture is ≥12%, the reduction of area is ≥55%, the impact energy absorption is ≥63 J, the Brinell hardness is ≤241, the grain size is ≥8.0 grade, and the single-sided decarburized layer is ≤2.5%. Specific Embodiments

[0047] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without making creative efforts shall fall within the protection scope of the present invention.

[0048] A 25Cr2MoVA thin plate for aircraft actuation, in terms of mass percentage, its chemical composition includes: C: 0.25 - 0.30%, Si: 0.10 - 0.40%, Mn: 0.40 - 0.70%, Cr: 1.50 - 1.80%, Mo: 0.25 - 0.35%, V: 0.15 - 0.30%, Ni: 0.03 - 0.05%, Al: 0.007 - 0.011%, P ≤ 0.015%, S ≤ 0.005%, and the balance is Fe.

[0049] Alternatively, C: 0.29 - 0.30%, Si: 0.10 - 0.20%, Mn: 0.40 - 0.70%, Cr: 1.50 - 1.80%, Mo: 0.25 - 0.35%, V: 0.15 - 0.30%, Ni: 0.03 - 0.05%, Al: 0.007 - 0.011%, P ≤ 0.015%, S ≤ 0.005%, and the balance is Fe.

[0050] The preparation method of the above-mentioned 25Cr2MoVA thin plate for aircraft use is specifically as follows:

[0051] 1) Prepare the furnace charge, melt it through an electric arc furnace + LF + VD, and obtain an alloy ingot meeting the chemical composition after cooling;

[0052] The furnace charge consists of carbon steel, CrMo scrap steel, and nickel-containing scrap steel;

[0053] The tapping temperature of the electric arc furnace is 1650 - 1700°C, the end-point carbon is 0.10% - 0.15%, the decarburization amount is ≥ 0.4%, and the end-point phosphorus is ≤ 0.003%;

[0054] In the early stage of the electric arc furnace smelting, reduce the content of harmful elements through processes such as slag-making and slag-skimming.

[0055] In the later stage of the electric arc furnace smelting, adjust the carbon content through in-furnace sampling to increase the carbon content.

[0056] During LF refining, ensure full blowing of Ar throughout the process, the white slag holding time is 30 - 35 min, and use a mixture of C powder and ferrosilicon powder for diffusion deoxidation during refining;

[0057] During VD vacuum refining, ensure the actual flow rate is 60 NL / min, the vacuum degree is below 67 Pa and maintained for 15 minutes, and the ladle temperature is: 1550 - 1560°C.

[0058] 2) Remove the defects on the surface of the alloy ingot, and perform electroslag remelting on the alloy ingot to obtain an electroslag ingot;

[0059] The specific steps for performing electroslag remelting on the alloy ingot are as follows:

[0060] Load the alloy ingot as a consumable electrode into the electroslag remelting furnace;

[0061] Select NEU-E50F as the electroslag material, place it at the bottom of the mold, and at the same time, set the remelting rate of electroslag remelting to 6.0 kg / min, the remelting power to 450 KW, and the swing parameter to 0.35 - 0.40;

[0062] Start the electroslag remelting furnace, the consumable electrode melts to form droplets and enters the mold, and after cooling in the mold for 2 h, demold to obtain a preliminary electroslag ingot;

[0063] After demoulding, heat the preliminary electroslag ingot to 650°C - 700°C and hold for 15 h;

[0064] After the heat preservation is completed, cool it in the furnace. When the temperature of the preliminary electroslag ingot drops to 500°C, take it out of the furnace and air-cool it to obtain the electroslag ingot.

[0065] 3) Remove the defects on the surface of the electroslag ingot;

[0066] Place the electroslag ingot in an electric furnace and heat the electroslag ingot at a heating rate not exceeding 100°C / h;

[0067] After the heating temperature reaches 1200°C, hold the electroslag ingot for 6 - 10 h;

[0068] After the heat preservation is completed, forge the electroslag ingot with a deformation amount of 20% - 30%. The rate gradually increases. The starting forging temperature ≥ 1100°C and the final forging temperature ≥ 800°C;

[0069] After forging is completed, air-cool it to obtain the forged blank.

[0070] 4) Place the forged blank in an electric furnace and heat it at a heating temperature of 1150 - 1200°C for 5 h;

[0071] After the heating is completed, hold for 2 - 3 h and perform hot rolling on the forged blank. The starting rolling temperature ≥ 1050°C and the final rolling temperature ≥ 800°C;

[0072] After hot rolling is completed, air-cool it to obtain the hot-rolled thin plate.

[0073] 5) Load the hot-rolled thin plate into the furnace cavity of the electric furnace at room temperature and place charcoal on both sides in the furnace cavity;

[0074] Heat the electric furnace to 660°C - 720°C to heat the hot-rolled thin plate, and the heating duration is 60 - 240 min;

[0075] After the heating is completed, cool it in the furnace; when the temperature of the electric furnace drops to 300°C, take it out of the furnace and air-cool it to complete the preparation of the 25Cr2MoVA thin plate for aircraft use and obtain the 25Cr2MoVA thin plate for aircraft use with a thickness of 3.0 - 9.0 mm.

[0076] The physical properties of the 25Cr2MoVA thin plate for aircraft use obtained according to the above preparation method of the 25Cr2MoVA thin plate for aircraft use are as follows: tensile strength ≥ 1080 MPa, yield strength ≥ 1000 MPa, elongation after fracture ≥ 12%, reduction of area ≥ 55%, impact energy absorption ≥ 63 J, Brinell hardness ≤ 241, grain size ≥ 8.0 grades, non-metallic inclusions ≤ 0.5 grades, single-sided decarburized layer ≤ 2.5%.

[0077] Specific examples are given below.

[0078] Example 1

[0079] A preparation method of 25Cr2MoVA thin plate for aircraft actuation, specifically:

[0080] 1) Prepare the furnace charge, which consists of carbon steel, CrMo scrap steel and nickel-containing scrap steel;

[0081] The furnace charge is melted by an electric arc furnace + LF + VD, and an alloy ingot meeting the chemical composition is obtained after cooling;

[0082] The tapping temperature of the electric arc furnace smelting is 1670 °C, the end point carbon is 0.10% - 0.15%, the decarburization amount is ≥ 0.4%, and the end point phosphorus is ≤ 0.003%;

[0083] Ar is blown throughout the LF refining process, the white slag holding time is 30 min, and C powder and ferrosilicon powder are used for mixed diffusion deoxidation in the refining diffusion deoxidation;

[0084] The actual flow rate during the VD vacuum refining process is 60 NL / min, the vacuum degree is maintained below 67 Pa for 15 minutes, and the ladle hanging temperature is 1550 °C;

[0085] 2) Remove the defects on the surface of the alloy ingot, and perform electroslag remelting on the alloy ingot to obtain an electroslag ingot;

[0086] The specific steps for performing electroslag remelting on the alloy ingot are as follows:

[0087] Load the alloy ingot as a consumable electrode into the electroslag remelting furnace;

[0088] Select NEU-E50F as the electroslag material, place it at the bottom of the mold, and at the same time, set the remelting rate of the electroslag remelting to 6.0 kg / min, the remelting power to 450 KW, and the swing parameter to 0.37;

[0089] Start the electroslag remelting furnace, the consumable electrode melts to form droplets and enters the mold, and after being cooled in the mold for 2 h, it is demolded to obtain a preliminary electroslag ingot;

[0090] After demolding, heat the preliminary electroslag ingot to 660 °C and keep it warm for 15 h;

[0091] After the heat preservation is completed, it is cooled with the furnace. When the temperature of the preliminary electroslag ingot drops to 500 °C, it is taken out of the furnace and air-cooled to obtain an electroslag ingot.

[0092] 3) Remove the defects on the surface of the electroslag ingot;

[0093] Place the electroslag ingot in an electric furnace and heat the electroslag ingot at a heating rate not greater than 100 °C / h;

[0094] After the heating temperature reaches 1200 °C, keep the electroslag ingot warm for 6 - 10 h;

[0095] After the heat preservation is completed, the electroslag ingot is forged with a deformation amount of 20%-30%, and the rate is gradually increased. The starting forging temperature is ≥1100°C, and the final forging temperature is ≥800°C;

[0096] After forging is completed, air cooling is carried out to obtain a forging blank.

[0097] 4) Place the forging blank in an electric furnace and heat it at a heating temperature of 1190°C for 5 h;

[0098] After the heating is completed, heat preservation is carried out for 2-3 h, and then hot rolling is carried out on the forging blank. The starting rolling temperature is ≥1050°C, and the final rolling temperature is ≥800°C;

[0099] After hot rolling is completed, air cooling is carried out to obtain a hot-rolled thin plate.

[0100] 5) Load the hot-rolled thin plate into the furnace cavity of an electric furnace at room temperature, and place charcoal on both sides in the furnace cavity;

[0101] Heat the hot-rolled thin plate by raising the temperature of the electric furnace to 660°C, and the heating duration is 60 min;

[0102] After the heating is completed, cool it with the furnace; when the temperature of the electric furnace drops to 300°C, take it out of the furnace and air cool it to complete the preparation of the 25Cr2MoVA thin plate for aircraft use, and obtain a 25Cr2MoVA thin plate for aircraft use with a thickness of 3.0 mm.

[0103] Example 2

[0104] A preparation method of a 25Cr2MoVA thin plate for aircraft use, specifically:

[0105] 1) Prepare furnace charges, and the furnace charges are composed of carbon steel, CrMo scrap steel and nickel-containing scrap steel;

[0106] The furnace charges are melted by an electric arc furnace + LF + VD, and an alloy ingot meeting the chemical composition is obtained after cooling;

[0107] The tapping temperature of the electric arc furnace is 1680°C, the end point carbon is 0.10%-0.15%, the decarburization amount is ≥0.4%, and the end point phosphorus is ≤0.003%;

[0108] Ar is blown throughout the LF refining process, the white slag holding time is 32 min, and C powder and ferrosilicon powder are used for mixed diffusion deoxidation in the refining diffusion deoxidation;

[0109] The actual flow rate during the VD vacuum refining process is 60 NL / min, the vacuum degree is maintained below 67 Pa for 15 minutes, and the ladle hanging temperature is 1555°C;

[0110] 2) Remove the defects on the surface of the alloy ingot, and carry out electroslag remelting on the alloy ingot to obtain an electroslag ingot;

[0111] The specific steps for electroslag remelting of the alloy ingot are as follows:

[0112] Load the alloy ingot as a consumable electrode into the electroslag remelting furnace;

[0113] Select NEU-E50F as the electroslag material and place it at the bottom of the crystallizer. At the same time, set the remelting rate of electroslag remelting to 6.0 kg / min, the remelting power to 450 KW, and the swing parameter to 0.37;

[0114] Start the electroslag remelting furnace. The consumable electrode melts to form droplets and enters the crystallizer. After cooling in the crystallizer for 2 h, demold to obtain a preliminary electroslag ingot;

[0115] After demolding, heat the preliminary electroslag ingot to 700 °C and hold for 15 h;

[0116] After holding, cool it in the furnace. When the temperature of the preliminary electroslag ingot drops to 500 °C, take it out of the furnace and air-cool to obtain the electroslag ingot.

[0117] 3) Remove the defects on the surface of the electroslag ingot;

[0118] Place the electroslag ingot in the electric furnace and heat the electroslag ingot at a heating rate not exceeding 100 °C / h;

[0119] After the heating temperature reaches 1200 °C, hold the electroslag ingot for 6 - 10 h;

[0120] After holding, forge the electroslag ingot with a deformation amount of 20% - 30%, and the rate gradually increases. The starting forging temperature ≥ 1100 °C, and the final forging temperature ≥ 800 °C;

[0121] After forging, air-cool to obtain the forged billet.

[0122] 4) Place the forged billet in the electric furnace and heat it at a heating temperature of 1190 °C for 5 h;

[0123] After heating, hold for 2 - 3 h, and perform hot rolling on the forged billet. The starting rolling temperature ≥ 1050 °C, and the final rolling temperature ≥ 800 °C;

[0124] After hot rolling, air-cool to obtain the hot-rolled thin plate.

[0125] 5) Load the hot-rolled thin plate into the furnace cavity of the electric furnace at room temperature and place charcoal on both sides in the furnace cavity;

[0126] Heat the hot-rolled thin plate by raising the temperature of the electric furnace to 690 °C, and the heating duration is 150 min;

[0127] After the heating is completed, it is cooled in the furnace; when the temperature of the electric furnace drops to 300 °C, it is taken out of the furnace and air-cooled to complete the preparation of the 25Cr2MoVA thin plate for aircraft use, and a 25Cr2MoVA thin plate with a thickness of 6.0 mm for aircraft use is obtained.

[0128] Example 3

[0129] A preparation method of a 25Cr2MoVA thin plate for aircraft use, specifically:

[0130] 1) Prepare the furnace charge, which consists of carbon steel, CrMo scrap steel and nickel-containing scrap steel;

[0131] The furnace charge is melted by an electric arc furnace + LF + VD, and an alloy ingot meeting the chemical composition is obtained after cooling;

[0132] The tapping temperature of the electric arc furnace is 1700 °C, the end point carbon is 0.10% - 0.15%, the decarburization amount is ≥ 0.4%, and the end point phosphorus is ≤ 0.003%;

[0133] Ar is blown throughout the LF refining process, the white slag holding time is 35 min, and the refining diffusion deoxidation is carried out by mixing C powder and ferrosilicon powder for diffusion deoxidation;

[0134] The actual flow rate during the VD vacuum refining process is 60 NL / min, the vacuum degree is maintained below 67 Pa for 15 minutes, and the ladle hanging temperature is 1556 °C;

[0135] 2) Remove the defects on the surface of the alloy ingot, and carry out electroslag remelting on the alloy ingot to obtain an electroslag ingot;

[0136] The specific steps for carrying out electroslag remelting on the alloy ingot are as follows:

[0137] Load the alloy ingot as a consumable electrode into the electroslag remelting furnace;

[0138] Select NEU-E50F as the electroslag material, place it at the bottom of the mold, and at the same time, set the remelting rate of electroslag remelting to 6.0 kg / min, the remelting power to 450 KW, and the swing parameter to 0.37;

[0139] Start the electroslag remelting furnace, the consumable electrode melts to form droplets and enters the mold, and after being cooled in the mold for 2 h, it is demolded to obtain a preliminary electroslag ingot;

[0140] After demolding, heat the preliminary electroslag ingot to 690 °C and keep it warm for 15 h;

[0141] After the heat preservation is completed, it is cooled in the furnace. When the temperature of the preliminary electroslag ingot drops to 500 °C, it is taken out of the furnace and air-cooled to obtain an electroslag ingot.

[0142] 3) Remove the defects on the surface of the electroslag ingot;

[0143] Place the electroslag ingot in an electric furnace and heat the electroslag ingot at a heating rate not exceeding 100 °C / h;

[0144] After the heating temperature reaches 1200 °C, keep the electroslag ingot insulated for 6 - 10 h;

[0145] After the insulation is completed, forge the electroslag ingot with a deformation amount of 20% - 30%, and the rate gradually increases. The starting forging temperature ≥ 1100 °C, and the final forging temperature ≥ 800 °C;

[0146] After forging is completed, air cool to obtain a forged blank.

[0147] 4) Place the forged blank in an electric furnace and heat it at a heating temperature of 1200 °C for 5 h;

[0148] After the heating is completed, keep it insulated for 2 - 3 h, and perform hot rolling on the forged blank. The starting rolling temperature ≥ 1050 °C, and the final rolling temperature ≥ 800 °C;

[0149] After hot rolling is completed, air cool to obtain a hot-rolled thin plate.

[0150] 5) Place the hot-rolled thin plate into the furnace cavity of an electric furnace at room temperature, and place charcoal on both sides in the furnace cavity;

[0151] Heat the hot-rolled thin plate by raising the temperature of the electric furnace to 720 °C, and the heating duration is 240 min;

[0152] After the heating is completed, cool it in the furnace; when the temperature of the electric furnace drops to 300 °C, take it out of the furnace and air cool to complete the preparation of the 25Cr2MoVA thin plate for aircraft use, and obtain a 25Cr2MoVA thin plate for aircraft use with a thickness of 9.0 mm.

[0153] Detect the chemical compositions of the 25Cr2MoVA thin plates for aircraft use prepared in Examples 1 - 3 and those prepared by the electric arc furnace smelting process. The detection results are shown in Table 1.

[0154] Table 1: Chemical composition table of 25Cr2MoVA thin plates for aircraft use

[0155]

[0156] Detect the room temperature tensile strength, room temperature yield strength, room temperature elongation, and hardness of the 25Cr2MoVA thin plates for aircraft use prepared in Examples 1 - 3 and those prepared by the electric arc furnace smelting process respectively. The detection results are shown in Table 2.

[0157] Table 2: Performance detection table

[0158]

[0159]

[0160] Combined with Table 1 and Table 2, it is not difficult to see that the 25Cr2MoVA thin plate for aircraft braking prepared by the present invention by appropriately increasing the carbon content and adopting the processes of electric arc furnace + LF + VD melting, electroslag remelting, forging, hot rolling and solution annealing has significantly reduced contents of harmful elements P and S;

[0161] Moreover, for the 25Cr2MoVA thin plate for aircraft braking with the same specification thickness, compared with the comparative example, the tensile strength, yield strength and grain size are all improved, and the non-metallic inclusions are significantly reduced.

[0162] As mentioned above, the above are only the specific embodiments 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 covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A 25Cr2MoVA thin plate for aircraft actuation, characterized in that, In terms of mass percentage, its chemical composition includes: C: 0.25 - 0.30%, Si: 0.10 - 0.40%, Mn: 0.40 - 0.70%, Cr: 1.50 - 1.80%, Mo: 0.25 - 0.35%, V: 0.15 - 0.30%, Ni: 0.03 - 0.05%, Al: 0.007 - 0.011%, P ≤ 0.015%, S ≤ 0.005%, and the balance is Fe.

2. The 25Cr2MoVA thin plate for aircraft actuation according to claim 1, wherein In terms of mass percentage, its chemical composition includes: C: 0.29 - 0.30%, Si: 0.10 - 0.20%, Mn: 0.40 - 0.70%, Cr: 1.50 - 1.80%, Mo: 0.25 - 0.35%, V: 0.15 - 0.30%, Ni: 0.03 - 0.05%, Al: 0.007 - 0.011%, P ≤ 0.015%, S ≤ 0.005%, and the balance is Fe.

3. A preparation method of 25Cr2MoVA thin plate for aircraft actuation, characterized in that, It includes the following steps: S1. Prepare the furnace charge, melt it through an electric arc furnace + LF + VD, and obtain an alloy ingot that meets the chemical composition after cooling. S2. Remove the defects on the surface of the alloy ingot, and perform electroslag remelting on the alloy ingot to obtain an electroslag ingot. S3. Remove the defects on the surface of the electroslag ingot, heat the electroslag ingot to 1200 °C and hold for 6 - 10 h. After the holding is completed, forge the electroslag ingot with a deformation amount of 20% - 30%, and the deformation amount increases slowly and the rate gradually accelerates. The starting forging temperature is ≥1100 °C, and the final forging temperature is ≥800 °C; after forging is completed, air-cool to obtain a forged blank. S4. Grind the forged blank to remove the scale on the surface of the forged blank; heat the forged blank to 1150 - 1200 °C and hold for 2 - 3 h. After the holding is completed, perform hot rolling on the forged blank, the starting rolling temperature is ≥1100 °C, and the final rolling temperature is ≥900 °C. After hot rolling is completed, air-cool to obtain a hot-rolled thin plate. S5. Heat the hot-rolled thin plate to 660 °C - 720 °C, and perform annealing treatment on the hot-rolled thin plate, and the annealing treatment duration is 60 - 240 min. After annealing is completed, complete the preparation of the 25Cr2MoVA thin plate for aircraft braking.

4. The preparation method of the 25Cr2MoVA thin plate for aircraft actuation according to claim 3, characterized in that: In step S1, the furnace charge consists of carbon steel, CrMo scrap steel, and nickel-containing scrap steel.

5. The preparation method of the 25Cr2MoVA thin plate for aircraft actuation according to claim 3, characterized in that: In step S2, the specific steps for performing electroslag remelting on the alloy ingot are as follows: Load the alloy ingot as a consumable electrode into the electroslag remelting furnace. Select NEU-E50F as the electroslag material, place it at the bottom of the mold, and at the same time, set the remelting rate of electroslag remelting to 6.0 kg / min, the remelting power to 450 KW, and the swing parameter to 0.35 - 0.

40. Start the electroslag remelting furnace, the consumable electrode melts to form droplets and enters the mold, and after cooling in the mold for 2 h, demold to obtain a preliminary electroslag ingot. After demolding, heat the preliminary electroslag ingot to 650 °C - 700 °C and hold for 15 h. After the holding is completed, cool it in the furnace. When the temperature of the preliminary electroslag ingot drops to 500 °C, take it out of the furnace and air-cool to obtain an electroslag ingot.

6. The preparation method of the 25Cr2MoVA thin plate for aircraft actuation according to claim 3, characterized in that, Step S3 is specifically as follows: Remove the defects on the surface of the electroslag ingot. Place the electroslag ingot in an electric furnace and heat the electroslag ingot at a heating rate not greater than 100 °C / h. After the heating temperature reaches 1200 °C, keep the electroslag ingot insulated for 6 - 10 h; After the insulation is completed, forge the electroslag ingot with a deformation amount of 20% - 30%, and the rate gradually increases. The starting forging temperature ≥ 1100 °C, and the final forging temperature ≥ 800 °C; After forging is completed, air cool to obtain a forged billet.

7. The preparation method of the 25Cr2MoVA thin plate for aircraft use according to claim 3, characterized in that, Step S4 is specifically as follows: Place the forged billet in an electric furnace and heat it at a heating temperature of 1150 - 1200 °C for 5 h; After heating is completed, keep it insulated for 2 - 3 h, and perform hot rolling on the forged billet. The starting rolling temperature ≥ 1050 °C, and the final rolling temperature ≥ 800 °C; After hot rolling is completed, air cool to obtain a hot-rolled thin plate.

8. The preparation method of the 25Cr2MoVA thin plate for aircraft actuation according to claim 3, characterized in that, Step S5 is specifically as follows: Load the hot-rolled thin plate into the furnace cavity of the electric furnace at room temperature, and place charcoal on both sides in the furnace cavity; Heat the hot-rolled thin plate by raising the temperature of the electric furnace to 660 °C - 720 °C, and the heating duration is 60 - 240 min; After heating is completed, cool it in the furnace; when the temperature of the electric furnace drops to 300 °C, take it out and air cool to complete the preparation of the 25Cr2MoVA thin plate for aircraft use, and obtain the 25Cr2MoVA thin plate for aircraft use.

9. The preparation method of the 25Cr2MoVA thin plate for aircraft use according to claim 8, characterized in that, The thickness of the 25Cr2MoVA thin plate for aircraft use is 3.0 - 9.0 mm.

10. The preparation method of the 25Cr2MoVA thin plate for aircraft actuation according to claim 8, characterized in that, The tensile strength of the 25Cr2MoVA thin plate for aircraft use ≥ 1080 MPa, yield strength ≥ 1000 MPa, elongation after fracture ≥ 12%, reduction of area ≥ 55%, impact energy absorption ≥ 63 J, Brinell hardness ≤ 241, grain size ≥ 8.0 grades, non-metallic inclusions ≤ 0.5 grades, single-sided decarburized layer ≤ 2.5%.

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