Method of manufacturing hr120 alloy ring forgings for aerospace gas turbines

Abstract

The application discloses a manufacturing method of an HR120 alloy ring forge piece for aerospace steam turbines, and the technical scheme comprises the following steps: step S1, preparing an alloy ingot; step S2, blanking; step S3, heating: the electroslag ingot is loaded into a furnace at a temperature of less than or equal to 600 DEG C, then heated to 910 DEG C, kept for a period of time, and heated to 1180 DEG C and kept for a period of time; step S4, forging: the forging blank is transferred to a press by a forging loading machine for forging, the last axial deformation of the forging is greater than or equal to 4, and the tangential deformation is greater than or equal to 1.5, and the forging comprises the following working steps: a first working step of upsetting the forging blank; a second working step of hole expanding of the forging blank; a third working step of first ring rolling of the forging blank; a fourth working step of rounding the sharp edges of the forging blank; a fifth working step of second ring rolling of the forging blank; step S5, cooling after forging: water cooling to obtain the forging piece; and step S6, performance heat treatment: the forging piece is subjected to solid solution, and the forging piece is uniformly deformed to obtain uniformly fine directional grains, so that the mechanical properties and grain size requirements of the product are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of alloy manufacturing technology, and particularly relates to a manufacturing method of HR120 alloy ring forge piece for aerospace gas turbine. BACKGROUND

[0002] With the development of economy and industrial level, the heavy gas turbine is the highest efficiency heat-power conversion equipment so far, and the gas turbine is widely used in the field of aerospace. Since the design and manufacturing of the gas turbine are extremely difficult, the gas turbine reflects the industrial level of a country. The internal working temperature of the current gas turbine can reach above 1300 degrees Celsius, and the alloy for manufacturing the gas turbine is required to have better high-temperature performance.

[0003] The HR120 alloy is a solid solution strengthened heat-resistant alloy, has excellent strength at high temperature, and has good resistance to carburization. The oxidation resistance of the alloy is equivalent to other widely used Fe-Ni-Cr materials, and the outstanding feature of the alloy is that the alloy still has outstanding structural strength at a temperature as high as 2500°F (1371°C). Therefore, the alloy is favored by researchers.

[0004] The current processing technology of the HR120 alloy forge piece is cold deformation, blanking of the ingot, upsetting, piercing, upsetting, multiple ring rolling, and rolling to the process size without special treatment process in the middle. There is no problem in using the traditional process to prepare small-size ring forge pieces, but now a large-size forge piece needs to be processed, and the following problems exist.

[0005] 1. Although the HR120 alloy has good strength, it also means that the machinability of the HR120 alloy is insufficient. To reach the process size, piercing, upsetting, and ring rolling need to be performed multiple times to reach the target size. The inner hole after piercing needs to be cleaned, the inner hole after upsetting needs to be cleaned, and the inner hole after each ring rolling needs to be cleaned. On the one hand, multiple cleanings result in serious weight loss of raw materials and damage to the alloy structure, and in severe cases, the product may even be scrapped.

[0006] 2. Multiple cleanings of the large ring forge piece also result in a prolonged production cycle.

[0007] 3. The large ring forge piece needs to undergo multiple deformation processes, and inevitably has errors in each deformation process. After multiple deformations, the errors are accumulated, resulting in uneven deformation of the forge piece, inability to obtain uniformly fine and directional grains, coarse grains of the forge piece, low grain size, and further affecting the mechanical properties of the product, and the product cannot meet the strict requirements of the gas turbine. SUMMARY

[0008] Aiming at the defects of the prior art, the aerospace steam turbine HR120 alloy ring forging manufacturing method has the advantages that a small amount of deformation process is adopted, heat preservation measures are matched during ring rolling, and a suitable performance heat treatment system is adopted, so that the forging is uniformly deformed to obtain uniformly fine directional grains, the problem of insufficient process performance is solved, and the mechanical performance and grain size requirements of the product are met.

[0009] The above technical purpose of the application is realized by the following technical scheme:

[0010] An aerospace steam turbine HR120 alloy ring forging manufacturing method comprises the following steps:

[0011] Step S1, alloy ingot preparation: raw materials are put into a furnace to smelt electroslag ingots;

[0012] Step S2, blanking: the feeding end and the electrode plate end of the electroslag ingot are cut off;

[0013] Step S3, heating: the electroslag ingot is loaded into a furnace at ≤600 ℃, then the temperature is raised to 910 ℃, then heat preservation is performed, and finally the temperature is raised to 1180 ℃ for heat preservation, to obtain a forging blank;

[0014] Step S4, forging, the forging blank is transferred to a press by a forging loading machine for forging, the last axial deformation amount of the forging is controlled to be ≥4, and the tangential deformation amount is ≥1.5, including the following working steps:

[0015] First working step: the forging blank is upset, then punched, and then returned to the furnace for heat preservation, the heat preservation time T3 is equal to the maximum effective section diameter of the steel ingot multiplied by 0.3 min / mm, and the contact surfaces of the upper and lower toolings of the equipment and the product need to be isolated by using heat preservation cotton;

[0016] Second working step: the forging blank is expanded by a mandrel, and one heating is completed, and the forging ratio is 1.6;

[0017] Third working step: the first heating of the ring rolling of the forging blank, the forging blank is wrapped with heat preservation cotton before ring rolling and then heated, the heat preservation time is 7-8 h, the heating and heat preservation coefficient is 1.5 min / mm, and the final forging temperature is controlled to be ≥900 ℃;

[0018] Fourth working step: the sharp edges of the inner and outer circles and the upper and lower end faces of the forging blank are rounded;

[0019] Fifth working step: the second heating of the ring rolling of the forging blank, the working procedure is the same as that of the first heating of the ring rolling, and the forging blank needs to be wrapped with heat preservation cotton before being loaded into the furnace, and the heat preservation time needs to be controlled to be 7-8 h;

[0020] Step S5, post-forging cooling: water cooling, to obtain a forging;

[0021] Step S6, performance heat treatment: the forging is solid-solved, and the solid-solution system is as follows: ≤600 DEG C is loaded into a furnace, the temperature is increased to 1200 DEG C ± 10 DEG C at a rate of ≤80 DEG C / h, and the temperature is kept for 6-8 h.

[0022] Further, in step S2, the feeding end of the electroslag ingot is removed by 3%-5%, the electrode plate end is removed by 5%-7%, the size of the electroslag ingot is φ600*1043 mm, and the weight of the electroslag ingot is 2.7T.

[0023] Further, in step S3, the holding time of the electroslag ingot at the stage of 910 DEG C is T1=the maximum effective cross section diameter of the electroslag ingot*0.3 min / mm, and the holding time of the electroslag ingot at the stage of 1180 DEG C is T2=the maximum effective cross section diameter of the electroslag ingot*0.6 min / mm.

[0024] Further, in step S3, the electroslag ingot is increased to 1180 DEG C at a rate of ≤70 DEG C / h.

[0025] Further, in the first working step of step S4, the upsetting of the forging blank is to Punching Reverberatory holding is kept for 135 min.

[0026] Further, in the second working step of step S4, the hole expanding of the forging blank is to

[0027] Further, in the third working step of step S4, the first ring rolling of the forging blank is to the size of φ2213 mm / φ1800 mm*210 mm.

[0028] Further, in the fourth working step of step S4, the rounding of the sharp edge of the forging blank is ≥10 mm.

[0029] Further, in the fifth working step of step S4, the second ring rolling of the forging blank is to the size of φ2900 mm / φ2534 mm*180 mm.

[0030] Further, in step S1, the chemical composition of the electroslag ingot comprises Ni: 35.0-39.0, Cu ≤0.5, Mn ≤1.5, C: 0.02-0.10, Si ≤1.0, S ≤0.03, Cr: 23.0-27.0, A1 ≤0.4, Ti ≤0.2, Nb and Ta: 0.4-0.9, Mo ≤1.00, P ≤0.04, W ≤0.50, Co ≤3.0, N: 0.15-0.30, and the rest is Fe.

[0031] According to the application, the following beneficial effects are achieved:

[0032] 1. After forging, two temperature gradient heat treatments are carried out, the heating temperature and holding time of the alloy are selected to improve the deformation ability of HR120 alloy, solve the difficulty of insufficient processability of HR120 alloy, so as to reduce the deformation times of the forged piece in the subsequent forging process, reduce the damage to the matrix of the forged piece, and be beneficial to improve the qualified rate of the forged piece.

[0033] 2. In the process of forging, the last axial deformation amount of the forging is controlled to be ≥4; the tangential deformation amount is ≥1.5, so that the forging is uniformly deformed in the axial and tangential directions, and uniform and fine directional grains are obtained, which meet the requirements of product mechanical properties and grain size.

[0034] 3. The blank before the product ring rolling must be wrapped with thermal insulation cotton, and the corner must be rounded between two ring rollings, and the product ring rolling is controlled within two fires to avoid the lack of product weight due to multiple deformations, and to avoid the increase of fire times which not only wastes energy consumption, but also is not conducive to the realization of product performance and grain size. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a step schematic diagram of the HR120 alloy ring forging manufacturing method for aerospace gas turbine.

[0036] Figure 2 It is a metallographic detection diagram of the HR120 alloy product. DETAILED DESCRIPTION

[0037] In order to make the purpose, technical scheme and advantages of the present application clearer, the following will make further detailed description of the scheme of the present application combined with the drawings and specific embodiments. According to the following description, the advantages and characteristics of the present application will be clearer.

[0038] EMBODIMENT:

[0039] A HR120 alloy ring forging manufacturing method for aerospace gas turbine, as shown in Figure 1 , comprises the following steps:

[0040] Step S1, preparing alloy ingot: raw materials are put into the furnace to smelt electroslag ingot. The chemical composition of the electroslag ingot includes Ni: 35.0-39.0, Cu≤0.5, Mn≤1.5, C: 0.02-0.10, Si≤1.0, S≤0.03, Cr: 23.0-27.0, Al≤0.4, Ti≤0.2, Nb and Ta: 0.4-0.9, Mo≤1.00, P≤0.04, W≤0.50, Co≤3.0, N: 0.15-0.30, and the rest is Fe.

[0041] Step S2, blanking. A weight of 2.7T electroslag ingot is prepared, and the diameter of the electroslag ingot is φ600mm. Then the feeding end and the electrode plate end of the electroslag ingot are cut off, 3%-5% of the feeding end is removed, 5%-7% of the electrode plate end is removed, and the blanking size is φ600mm*1043mm.

[0042] Step S3, heating. The electroslag ingot is ≤600℃ loaded into the furnace, heated to 910℃ according to the power, and kept for T1 (T1=the maximum effective cross-sectional diameter of the electroslag ingot*0.3min / mm), the holding time is 3h, and then heated to 1180℃ at a rate of ≤70℃ / h, and kept for T2 (T2=the maximum effective cross-sectional diameter of the electroslag ingot*0.6min / mm), the holding time is 6h.

[0043] Step S4, forging. The forging blank is transferred to the press by the forging loading machine for forging, including the following working steps:

[0044] The first working step: the forging blank is upset to φ1280mm*230mm, punched to φ380mm, and returned to the furnace for 135min of heat preservation.

[0045] The second working step: the forging blank is expanded to φ1590mm / φ1000mm*230mm, completed in one fire, and the forging ratio is 1.6, so as to ensure that the product has sufficient tangential deformation.

[0046] The third working step: the forging blank is rolled to the size of φ2213mm / φ1800mm*210mm in the first fire (pre-rolling), before the forging blank is loaded into the furnace, it must be wrapped with heat preservation cotton, and the heat preservation time needs to be 7-8h, and the deformation degree of the first fire needs to be strictly controlled, the first fire cannot be rolled too much, and the ring cannot be continued to be rolled because no cracks appear. In addition, the final forging temperature of the forging blank is guaranteed to be ≥900℃.

[0047] The fourth working step: the forging blank is transferred from the press to the metalworking equipment, and the sharp edge of the forging blank is rounded, the rounding size is R≥10mm, so as to avoid the product from the sharp edge of the workpiece to produce cracks in the second rolling ring.

[0048] The fifth working step: the forging blank is rolled to φ2900mm / φ2534mm*180mm in the second fire (final rolling), and this process is the same as the first fire, the product needs to be wrapped with heat preservation cotton before the ring blank is loaded into the furnace, and the heat preservation time needs to be controlled in 7-8h, and it is noted that the product must be completed within two fires.

[0049] In the whole forging process, the last axial deformation of the forging blank is ≥4; the tangential deformation is ≥1.5. The forging piece is guaranteed to have sufficient deformation in the axial and tangential directions, and uniform and fine directional grains are obtained.

[0050] Step S5, cooling after forging. The forging blank is cooled to room temperature in the water cooling mode to obtain the forged piece.

[0051] Step S6, performance heat treatment: the forging is solution treated, and the solution treatment system is as follows: ≤600℃ into the furnace, heated to 1200℃±10℃ at a rate of ≤80℃ / h, and kept for 6-8h.

[0052] Step S7, surface detection. First, the roughness of the forging is detected, and the roughness of the four sides of the forging is required to be at least Ra6.3. Ultrasonic detection is performed, and the product is detected according to the "attenuation of direct rear wall reflection not exceeding 20%" specified in SA388 to determine whether it is qualified.

[0053] Step S8, physical and chemical detection: a test ring is taken from one end of the forging for mechanical property, grain size, and hardness detection.

[0054] Comprehensive mechanical property test of the forging:

[0055] The staff respectively performed comprehensive mechanical experiments on the two groups of samples, and the detailed detection results are shown in Table 1.

[0056]

[0057] Table 1

[0058] Metallographic detection of the forging:

[0059] Experimental preparation: product samples are taken from Example 1, and are respectively recorded as Sample 1.

[0060] Detection specification: X1000, 10μm

[0061] Detection results:

[0062] Sample 1 is detected for forging grain size according to ASTM E112-13, and the detection result is 6.0 grade, which meets the acceptance standard (≥3.0 grade), the grain structure is fine, and there is no pitting, porosity, crack, and other defects.

[0063] Each technical feature of the above-described embodiments can be combined arbitrarily, and in order to make the description simple, each technical feature in the above-described embodiments is not described in all possible combinations, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the description.

[0064] The above-described embodiments only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the protection scope of the patent of the present application should be subject to the appended claims.

Claims

1. A method of manufacturing a HR120 alloy ring forging for aerospace gas turbine engines, characterized by, The method comprises the following steps: Step S1, preparing an alloy ingot: raw materials are put into a furnace to smelt an electroslag ingot; Step S2, cutting: the feeding end and the electrode plate end of the electroslag ingot are cut off; the feeding end of the electroslag ingot is removed by 3%-5%, and the electrode plate end is removed by 5%-7%; the size of the electroslag ingot after cutting is φ600*1043mm, and the weight of the electroslag ingot is 2.7T; Step S3, heating: the electroslag ingot is put into a furnace at ≤600℃, then the temperature is raised to 910℃, then the temperature is kept constant, finally the temperature is raised to 1180℃ and kept constant, so that a forging blank is obtained; the holding time of the electroslag ingot at 910℃ is T1=the maximum effective cross-sectional diameter of the electroslag ingot*0.3min / mm, the holding time of the electroslag ingot at 1180℃ is T2=the maximum effective cross-sectional diameter of the electroslag ingot*0.6min / mm, and the electroslag ingot is raised to 1180℃ at a rate of ≤70℃ / h; Step S4, forging, the forging blank is transferred to a press by a forging loading machine for forging, the last axial deformation of the forging is controlled to be ≥4, and the tangential deformation is controlled to be ≥1.5, which comprises the following working steps: The first working step is upsetting of the forging blank, then punching, and returning to the furnace for heat preservation; the upsetting of the forging blank is to φ1280mm*230mm, the punching is φ380mm, and the heat preservation time in the furnace is 135min; The second working step is to expand the hole of the forging blank, which is completed in one heating, and the forging ratio is 1.6; The third working step is to roll the ring of the forging blank in the first heating, before rolling the ring, the forging blank is wrapped with heat preservation cotton for heating, and the heat preservation time is 7-8h, and the final forging temperature is controlled to be ≥900℃; The fourth working step is to round the sharp edges of the inner and outer circles and the upper and lower end faces of the forging blank; The fifth working step is to roll the ring of the forging blank in the second heating, the working procedure is the same as that in the first heating, and the forging blank needs to be wrapped with heat preservation cotton before being put into the furnace, and the heat preservation time needs to be controlled to be 7-8h; Step S5, cooling after forging: water cooling, so that a forged piece is obtained; Step S6, performance heat treatment: the forged piece is subjected to solid solution, and the solid solution system is as follows: ≤600℃ is put into a furnace, the temperature is raised to 1200℃±10℃ at a rate of ≤80℃ / h, and the heat preservation time is 6-8h.

2. A method of manufacturing a HR120 alloy ring forge for aerospace gas turbine engines as defined in claim 1, wherein: In the second working step of step S4, the hole expanding size of the forging blank is φ1590mm / φ1000mm*230mm.

3. A method of manufacturing a HR120 alloy ring forge for aerospace gas turbine engines as defined in claim 2 wherein: In the third working step of step S4, the first heating of the forging blank is rolled to the size of φ2213mm / φ1800mm*210mm.

4. A method of manufacturing a HR120 alloy ring forge for aerospace gas turbine engines as defined in claim 3 wherein: In the fourth working step of step S4, the rounding size of the sharp edges of the forging blank is ≥10mm.

5. A method of manufacturing a HR120 alloy ring forge for aerospace gas turbine engines as defined in claim 4 wherein: In the fifth working step of step S4, the second heating of the forging blank is rolled to the size of φ2900mm / φ2534mm*180mm.

6. A method of manufacturing a HR120 alloy ring forge for aerospace gas turbine engines as recited in claim 1, characterized by: In step S1, the chemical composition of the electroslag ingot comprises Ni: 35.0-39.0, Cu≤0.5, Mn≤1.5, C: 0.02-0.10, Si≤1.0, S≤0.03, Cr: 23.0-27.0, Al≤0.4, Ti≤0.2, Nb and Ta: 0.4-0.9, Mo≤1.00, P≤0.04, W≤0.50, Co≤3.0, N: 0.15-0.30, and the rest is Fe.

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