Uniform-structure Haynes242 forge piece and forming method thereof

Abstract

The invention belongs to the technical field of aviation annular forge piece forming, and particularly discloses a Haynes 242 forge piece with a uniform structure and a forming method of the Haynes 242 forge piece, and the forming method comprises the following steps of blanking, upsetting and punching, trestle chambering and end face flattening, rolling and heat treatment. In the upsetting punching process, the blanked blank is heated to the first forging temperature of 1020-1060 DEG C; in the mandrel supporter chambering flat end face, the blank is heated to the second forging temperature of 1020-1060 DEG C, and the forging deformation is 10%-15%; rolling comprises prefabrication and finish rolling, in the pre-rolling process, heating is conducted till the third forging temperature ranges from 1020 DEG C to 1060 DEG C, rolling is conducted through at least one heating number, and the rolling deformation of each heating number is controlled to range from 10% to 20%; and the blank is heated to the fourth forging temperature in a step heating mode in the final rolling process, the fourth forging temperature ranges from 1030 DEG C to 1050 DEG C, the forging deformation ranges from 10% to 15%, the appearance shape of the obtained Haynes242 forged piece meets the part machining size requirement, cracks are few in the production process, and the uniform structure and mechanical performance meeting the standard requirement are obtained.

Description

Technical Field

[0001] The invention relates to the technical field of aviation ring forging forming, and in particular to a Haynes242 forging with uniform structure and a forming method thereof. Background Art

[0002] Haynes242 alloy is a new type of precipitation hardened nickel-based low expansion high temperature alloy with superior high temperature performance and good processability. High temperature low expansion alloys are widely used to make gas turbine and steam turbine sealing rings, shafts, casings, blades, fasteners and other structural components that require approximately constant dimensions in a certain high temperature environment. Therefore, Haynes242 alloy is widely used in high-quality structural components of civil aviation engines. It is estimated that for every 0.01 increase in the ratio of the gap distance from the fan blade to the seal to the blade height, the fuel efficiency of the turbine engine will decrease by about 0.8% to 1.2%, and the fuel consumption rate will increase by about 2%. In order to save fuel consumption, the organizational performance requirements of Haynes242 alloy structural components are relatively high. Therefore, it is necessary to study the relationship between the hot working parameters and the organization of Haynes242 alloy.

[0003] Haynes242 alloy structural parts are generally ring forgings, which are formed by ring rolling process. Ring rolling process is a local continuous forming process. There are many grades of high-temperature alloys, and each alloy grade has its own organizational and performance characteristics. Therefore, it is difficult to uniformly control the organizational homogenization through unified parameters. The forging temperature range of Haynes242 alloy is narrow. The forging temperature used in the existing Haynes242 alloy forming process is relatively low. The deformation resistance of the forging process is large, and the surface cracks of the material are serious. If the temperature is too high, it is easy to cause coarse grain size or organizational performance, which does not meet the forging specification requirements (Haynes242 grain size requires uniform 4 or finer, preferably between 4-6, with both good strength performance and good plasticity and durability), thus causing machining deformation, resulting in low forming efficiency of forgings, and reducing the service life of forgings. The organization and performance of Haynes242 alloy forgings are not easy to control, and there is no reference value between its forging parameters and the performance organizational law of the product. It is necessary to develop a forming method suitable for Haynes242 alloy. Summary of the invention

[0004] The purpose of the present invention is to overcome the problem of cracks generated during the forming process of the existing Haynes242 forgings and the resulting uneven structure, and to provide a Haynes242 forging with uniform structure and a forming method thereof.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions:

[0006] A forming method for a uniform Haynes 242 forging comprises the following steps in sequence: blanking, upsetting and punching, rack expansion and flat end surface, rolling and heat treatment;

[0007] During the upsetting and punching, the blank is heated to a first forging temperature, and the first forging temperature is 1020-1060°C;

[0008] The blank is heated to the second forging temperature in the flat end face of the horse frame expansion hole, the second forging temperature is 1020-1060°C, and the forging deformation is 10%-15%;

[0009] The rolling includes pre-rolling and final rolling. During the pre-rolling, the steel is heated to a third forging temperature, which is 1020-1060° C. The steel is rolled at least once, and the deformation of each rolling is controlled at 10%-20%.

[0010] The final rolling adopts a step heating method to heat the blank to the fourth forging temperature, the fourth forging temperature is 1030-1050° C., and the forging deformation is 10%-15%.

[0011] In the technical solution of the present invention, the forming process comprises blanking, upsetting and punching, rack expansion and flat end surface, pre-rolling, final rolling and heat treatment. During the upsetting and punching, the blank after blanking is heated to the first forging temperature, and the first forging temperature is 1020-1060°C, which can improve the axial fluidity of the alloy material, thereby ensuring the uniformity of the blank deformation and material organization, preventing the local temperature of the ring blank from rising during the upsetting process, resulting in uneven grain growth, eliminating bulging and rounded corners during the forming process, reducing the generation of cracks, and improving the blank. Material consistency; the second forging temperature is heated to 1020-1060℃ during the horse frame expansion, and the forging deformation is controlled at 10%-15%. The second forging temperature is heated to 1020-1060℃ during prefabrication, and the forging deformation is controlled at 10%-20%. The rolling size and deformation are strictly controlled. The final forging is heated to 1030-1050℃ by step heating, and the forging deformation is controlled at 10%-15%, which can make the organization uniform and eliminate the uneven organization caused by the previous rolling.

[0012] The forming method of the present invention solves the problem of cracks generated during the forming process of Haynes242 forgings, and solves the problem of uneven grain size of Haynes242 forgings and easy deformation during machining. The ring forgings for Haynes242 civil aviation engines manufactured by the manufacturing method meet the requirements of the machining dimensions of the parts, have few cracks during the production process, and obtain uniform organization and mechanical properties that meet the standard requirements. The ring forgings for Haynes242 civil aviation engines manufactured by the manufacturing method can effectively reduce the weight of the forgings and reduce the cost. The yield rate of forging manufacturing is improved and the consumption of materials is reduced.

[0013] As a preferred solution of the present invention, the raw material Haynes242 is sawn according to certain specifications according to the forging specifications and the required surplus material. The raw material is a bar with a diameter of Φ150mm to Φ300mm and a height-to-diameter ratio of 2.0 to 3.5.

[0014] As a preferred embodiment of the present invention, in the upsetting and punching step, the blank is heated to the first forging temperature, and the upsetting deformation is 20% to 50%; the diameter of the punch used is 1 / 3 to 1 / 2 of the diameter of the blank after upsetting.

[0015] As a more preferred embodiment of the present invention, in the upsetting and punching step, closed upsetting and punching are used, and the upsetting ratio of the forging is 1.8 to 3. During the upsetting and punching, bulging will occur, and the end face will have a large fillet, which will affect the subsequent horse frame expansion and rolling billet quality. In addition, the material is prone to cracking. Therefore, closed upsetting and punching are used to strictly control the temperature and deformation during the upsetting and punching process, and the billet bulging is refined to improve the billet quality and product consistency, and reduce the generation of cracks. Specifically, the upsetting ratio of the ring forging is 2.

[0016] As a preferred embodiment of the present invention, the pre-rolling adopts multi-pass rolling, the number of passes is 2 to 4 passes.

[0017] As a preferred embodiment of the present invention, the rolling deformation in each round of pre-rolling is controlled within a range of 10% to 15%.

[0018] As a preferred solution of the present invention, the final rolling adopts a step heating method, which is: the ring blank is loaded into a heating furnace with a set temperature, and when the temperature reaches 1070-1110°C, it is kept at 1070-1110°C for 40-75 minutes, then the temperature is lowered to 1030-1050°C with the furnace, and kept at 1030-1050°C for 0-120 minutes. In the above technical solution, the final rolling forging adopts a new step heating method, so that a uniform structure is obtained and good mechanical properties are guaranteed.

[0019] As a more preferred embodiment of the present invention, in the step heating method, the time calculation method for the insulation treatment at 1030-1050°C is the first effective wall thickness × 0.5-0.8 min / mm + (5-15) min, and the first effective wall thickness is the effective wall thickness of the Haynes242 forging before final rolling.

[0020] As a preferred embodiment of the present invention, the heat treatment method is: subjecting the Haynes242 alloy forging to solution heat treatment at 1030-1090°C for 30-100 minutes; and then subjecting the forging to aging heat treatment at 600-700°C for 40-60 hours.

[0021] As a preferred embodiment of the present invention, the forming method specifically comprises the following steps:

[0022] Step 1, cutting: sawing the Haynes242 bar according to the specifications;

[0023] Step 2, upsetting and punching: heating the Haynes242 bar to a first forging temperature of 1020-1060° C., upsetting and punching the heated and heat-insulated Haynes242 bar to form a first ring blank;

[0024] Step 3, horse rack reaming flat end face: heating the first ring blank to a second forging temperature of 1020-1060° C., using a horse bar and a horse rack reaming device to reaming the hole, and controlling the forging deformation amount to 10%-15% to form a second ring blank;

[0025] Step 4, pre-rolling: heating the second ring blank to a third forging temperature of 1020-1060° C., pre-rolling the heated and heat-insulated second ring blank through at least one fire, with the rolling deformation amount of each fire being controlled at 10%-15%, to form a third ring blank;

[0026] Step 5, final rolling: heating the third ring blank by a step heating method, the step heating method is: loading the ring blank into a heating furnace with a set temperature, when the temperature reaches 1070-1110° C., heat preservation treatment is performed for 40-75 minutes, then the temperature is lowered to 1030-1050° C. with the furnace, and heat preservation treatment is performed for 0-120 minutes at 1030-1050° C., the third ring blank is final rolled, and the forging deformation is controlled at 10%-15% to form a fourth ring blank;

[0027] Step 6, subjecting the fourth ring blank to heat treatment to obtain a Haynes 242 forging.

[0028] Another aspect of the present invention provides a uniformly organized Haynes 242 forging, which is prepared by the forming method of the uniformly organized Haynes 242 forging.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The present invention provides a forming method for Haynes242 forgings. In the blank making process of the upsetting punching and the rack expansion steps, the forging temperature and deformation are strictly controlled to refine the grains and reduce the generation of cracks. The intermediate rolling stage of the pre-rolling step adopts a forging temperature of 1020-1060° C., and the deformation of each rolling is controlled by 10%-20%. The final rolling process adopts a step heating method to heat to 1030-1050° C. and control the deformation by 10%-15%, so that the grains are kept from growing during the forging process. After rolling, heat treatment is performed, and the prepared Haynes242 forgings have good mechanical properties, fatigue resistance and creep resistance, overcome crack defects, improve manufacturing efficiency, and greatly reduce scrap rate. The grains of the forgings are relatively uniform, at levels 4-7, and no obvious segregation of fine grain areas and coarse grain areas is observed. Under the premise of ensuring the mechanical properties of the forgings, the uniformity of the organization of the forgings is improved.

[0031] 2. In the forming process of the present invention, the pre-rolling adopts multi-fire rolling. By controlling the deformation temperature and deformation amount during the pre-rolling and final rolling processes, the ring blank is transferred to both ends, so that the special-shaped ring blank is closer to the target forging, making the Haynes242 material easier to roll and reducing the difficulty of rolling forming. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 Schematic diagram of the structure of the Haynes242 forging in Example 1;

[0033] Figure 2 Schematic diagram of the step heating method in the forming method of Example 1;

[0034] Figure 3 This is the microstructure diagram of the Haynes242 forging in Example 1 under a high-power microscope;

[0035] Figure 4 This is the microstructure diagram of the Haynes242 forging in Example 2 under a high-power microscope;

[0036] Figure 5 This is the microstructure diagram of the Haynes242 forging in Comparative Example 1 under a high-power microscope;

[0037] Figure 6 This is the microstructure diagram of the Haynes242 forging in Comparative Example 2 under a high-power microscope;

[0038] Marking in the figure: 1-forging. DETAILED DESCRIPTION

[0039] In order to more clearly describe the invention purpose, technical scheme and technical effect advantages in the specific implementation case of the present invention, the scheme in the specific embodiment will be described in detail in combination with the drawings of the specification of the present invention. The specific technical scheme involved in the following specific embodiments is only for a clear and complete description of the innovative technical scheme of the present invention. It is only a part of the specific implementation scheme that can be adopted by the present invention, not all embodiments, and should not be understood as a limitation on the innovative scheme of the present invention. Any scheme adopting the same inventive concept of the present invention should be included in the protection scope of the present invention.

[0040] Secondly, the description of the drawings in the specific embodiments of the present invention is only for the convenience of technical personnel to understand the solution of the present invention. The partial details in the drawings are for the convenience of clearly presenting the technical solution. It should not be considered that all technical features in the drawings must be included in the specific implementation cases, and the detailed features in the drawings should not be identified as additional limitations on the innovative technical solution of the present invention. The components in the various embodiments described and shown in the drawings can be combined and arranged according to different configurations, and these changes in combination and arrangement should be identified as part of the entire embodiment of the innovative solution of the present invention and included in the scope of protection of the present invention.

[0041] In summary, the schemes or descriptions presented in the specific embodiments and drawings of the present invention are not intended to limit the scope of protection claimed, but are merely selected embodiments / cases to help technicians understand the relevant innovative solutions. Based on these embodiments, all other equivalent or parallel embodiments obtained by those skilled in the art without creative work are within the scope of protection claimed by the present invention.

[0042] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific parameters.

[0043] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be 3, 4, 5, 6, 7, 8, 9, etc., or even more than 9.

[0044] The Hayness242 alloy used in the embodiment of the present invention is a high temperature low expansion Ni-Mo-Cr alloy, and its chemical composition is molybdenum (Mo): 24.00-26.00%; chromium (Cr): 7.00-9.00%; iron (Fe): ≤2.00%; cobalt (Co): ≤2.50%; manganese (Mn): ≤0.80%; silicon (Si): ≤0.80%; aluminum (Al): ≤0.50%; carbon (C): ≤0.03%; boron (B): ≤0.006%; copper (Cu): ≤0.50%. The operating temperature of Haynes242 is limited to about 650°C.

[0045] Typical ring forging dimensions for Haynes 242 are as follows Figure 1 As shown, the inner diameter is Φ300~Φ500mm, the height is 80~180mm, and the wall thickness is 30~60mm.

[0046] Example 1

[0047] In this embodiment, Haynes 242 forgings are prepared. Forging 1 has a rectangular cross section. Figure 1 As shown, the inner diameter is Φ400mm, the height is 100mm, the wall thickness is 30mm, and the forming method includes the following steps:

[0048] Step 1, cutting: Cut the Haynes242 bar into specified lengths on a sawing machine;

[0049] Step 2, upsetting and punching: the Haynes242 bar is heated to a first forging temperature of 1020-1040° C. in an electric furnace, and the holding time is: the effective thickness of the bar blank×6 min / 10 mm. The heated and held Haynes242 bar is subjected to closed upsetting on a fast forging machine, and the upsetting ratio is 2. The upsetting bar is punched with a punch so that the center is opened to form a first ring blank;

[0050] Step 3, horse rack expansion and flat end surface: the first ring blank is heated to the second forging temperature of 1020-1040°C by an electric furnace, the heated first ring blank is placed on a horse bar, and the outer cylindrical surface of the ring is pressed with a hammer to expand the hole on the horse rack, so that the inner and outer diameters of the blank are increased, the wall thickness is reduced, and the forging deformation is controlled at 10%-15%, so that the forging can reach the minimum size required by the rolling mill, and the second ring blank is formed;

[0051] Step 4, pre-rolling: the second ring blank is heated to the third forging temperature of 1020-1040°C by an electric furnace, and the holding time is: the effective thickness of the second ring blank × 6min / 10mm, and pre-rolled in a CNC radial axis ring rolling machine through two fires, and the rolling deformation of each fire is controlled at 10%-15%, and the rolling size of each fire is strictly controlled to form a third ring blank; after rolling, shot peening and coloring inspection are carried out to ensure that defects such as cracks are completely eliminated before transferring to the next step;

[0052] Step 5, final rolling: The third ring blank is heated by step heating, and the heating temperature is Figure 2 The step heating method is as follows: the ring blank is loaded into a heating furnace at 1070-1110°C. When the temperature reaches 1070-1110°C, it is heat-insulated at 1070-1110°C for 40-75min, then cooled to 1030-1050°C with the furnace, and heat-insulated at 1030-1050°C for 0-120min. The heated and heat-insulated third ring blank is final rolled in a CNC radial axis ring rolling machine, and the forging deformation is controlled at 10%-15% to form a fourth ring blank. After rolling, shot peening and coloring inspection are carried out to ensure that defects such as cracks are completely eliminated before proceeding to the next step.

[0053] Step 6, subjecting the fourth ring blank to solution heat treatment and aging heat treatment to obtain a Haynes 242 forging.

[0054] Example 2

[0055] In this embodiment, Haynes 242 forgings are prepared. Forging 1 is a forging with a flange ring, with an inner diameter of Φ600 mm, a height of 180 mm, and a wall thickness of 25 mm. The forming method includes the following steps:

[0056] Step 1, cutting: Cut the Haynes242 bar into specified lengths on a sawing machine;

[0057] Step 2, upsetting and punching: the Haynes242 bar is heated to a first forging temperature of 1030-1060° C. in an electric furnace, and the holding time is: effective thickness of the bar blank×6 min / 10 mm. The heated and held Haynes242 bar is subjected to closed upsetting on a fast forging machine, and the upsetting ratio is 2. The upsetting bar is punched with a punch to make the center of the bar open to form a first ring blank;

[0058] Step 3, horse rack expansion and flat end surface: the first ring blank is heated to the second forging temperature of 1030-1060°C by an electric furnace, the heated first ring blank is placed on a horse bar, and the outer cylindrical surface of the ring is pressed with a hammer to expand the hole on the horse rack, so that the inner and outer diameters of the blank are increased, the wall thickness is reduced, and the forging deformation is controlled at 10%-15%, so that the forging can reach the minimum size required by the rolling mill, and the second ring blank is formed;

[0059] Step 4, pre-rolling: heating the second ring blank to a third forging temperature of 1030-1060° C. in an electric furnace, holding the second ring blank for an effective thickness of 6-8 min / 10 mm, and pre-rolling the second ring blank in a CNC radial axis ring rolling machine to form a rectangular cross-section ring blank, with the rolling deformation controlled at 10%-15%;

[0060] The rectangular cross-section ring blank is heated again to the third forging temperature of 1030-1060°C and kept warm, and the ring blank is rolled in the CNC radial axis ring rolling machine with the core roller die and the main roller die, and the rolling deformation is controlled at 10%-15% to form the third ring blank with a special cross-section; after rolling, shot peening and coloring inspection are carried out to ensure that defects such as cracks are completely eliminated before moving to the next step;

[0061] Step 5, final rolling: the third ring blank is heated by a step heating method, the step heating method is: the ring blank is loaded into a 1070-1110°C heating furnace, when the temperature reaches 1070-1110°C, it is heat-insulated for 50-60min at 1070-1110°C, then cooled to 1030-1050°C with the furnace, and heat-insulated for 60-80min at 1030-1050°C, the heated and heat-insulated third ring blank is rolled in a CNC radial shaft ring rolling machine with the core roller mold and the main roller mold, the forging deformation is controlled at 10%-15%, and a fourth ring blank with a flange is formed, and after rolling, shot peening and coloring inspection are performed to ensure that defects such as cracks are completely eliminated before proceeding to the next step.

[0062] Step 6, subjecting the fourth ring blank to solution heat treatment and aging heat treatment to obtain a Haynes 242 forging.

[0063] Comparative Example 1

[0064] The Haynes242 forging of this embodiment 1 is the same as that of embodiment 1, with an inner diameter of Φ400 mm, a height of 100 mm, and a wall thickness of 30 mm. The forming method is different from that of embodiment 1. The main difference is that the step heating method is not used during the final rolling. The forming method of this embodiment includes the following steps:

[0065] Step 1, cutting: Cut the Haynes242 bar into specified lengths on a sawing machine;

[0066] Step 2, upsetting and punching: the Haynes242 bar is heated to 1020-1060° C. in an electric furnace, and the holding time is: effective thickness of the bar blank×6 min / 10 mm. The heated and held Haynes242 bar is subjected to closed upsetting on a fast forging machine, and the upsetting ratio is 2. The upsetting bar is punched with a punch to make the center of the bar open, thereby forming a first ring blank.

[0067] Step 3, horse rack expansion and flat end surface: the first ring blank is heated to 1020-1060°C in an electric furnace, the heated first ring blank is placed on a horse bar, and the outer cylindrical surface of the ring is pressed with a hammer to expand the hole on the horse rack, so that the inner and outer diameters of the blank are increased, the wall thickness is reduced, and the forging deformation is controlled at 10%-15%, so that the forging can reach the minimum size required by the rolling mill, and the second ring blank is formed;

[0068] Step 4, pre-rolling: the second ring blank is heated to the third forging temperature of 1020-1060°C by an electric furnace, and the holding time is: the effective thickness of the second ring blank × 6min / 10mm, and pre-rolled in a CNC radial axis ring rolling machine through two fires, and the rolling deformation of each fire is controlled at 10%-15%, and the rolling size of each fire is strictly controlled to form a third ring blank; after rolling, shot peening and coloring inspection are carried out to ensure that defects such as cracks are completely eliminated before transferring to the next step;

[0069] Step 5, final rolling: the third ring blank is heated to 1050-1080°C in an electric furnace, and the holding time is: the effective thickness of the third ring blank × 6min / 10mm. The heated and held third ring blank is final rolled in a CNC radial axis ring rolling machine, and the forging deformation is controlled at 10%-15% to form a fourth ring blank. After rolling, shot peening and coloring inspection are carried out to ensure that defects such as cracks are completely eliminated before proceeding to the next step.

[0070] Step 6, subjecting the fourth ring blank to solution heat treatment and aging heat treatment to obtain a Haynes 242 forging.

[0071] Comparative Example 2

[0072] The Haynes242 forging of this embodiment 1 is the same as that of embodiment 1, with an inner diameter of Φ400 mm, a height of 100 mm, and a wall thickness of 30 mm. The forming method is different from that of embodiment 1. The main difference is that the forging temperature is different and the step heating method is not used during the final forging. The forming method of this embodiment includes the following steps:

[0073] Step 1, cutting: Cut the Haynes242 bar into specified lengths on a sawing machine;

[0074] Step 2, upsetting and punching: the Haynes242 bar is heated to a first forging temperature of 1050-1080° C. in an electric furnace, and the holding time is: effective thickness of the bar blank×6 min / 10 mm. The heated and held Haynes242 bar is subjected to closed upsetting on a fast forging machine, and the upsetting ratio is 2. The upsetting bar is punched with a punch so that the center is opened to form a first ring blank;

[0075] Step 3, horse rack expansion and flat end surface: the first ring blank is heated to the second forging temperature of 1050-1080°C by an electric furnace, the heated first ring blank is placed on a horse bar, and the outer cylindrical surface of the ring is pressed with a hammer to expand the hole on the horse rack, so that the inner and outer diameters of the blank are increased, the wall thickness is reduced, and the forging deformation is controlled at 10%-15%, so that the forging can reach the minimum size required by the rolling mill, and the second ring blank is formed;

[0076] Step 4, pre-rolling: the second ring blank is heated to the third forging temperature of 1050-1080°C by an electric furnace, and the holding time is: the effective thickness of the second ring blank × 6min / 10mm, and pre-rolled in a CNC radial axis ring rolling machine through two fires, and the rolling deformation of each fire is controlled at 10%-15%, and the rolling size of each fire is strictly controlled to form a third ring blank; after rolling, shot peening and coloring inspection are carried out to ensure that defects such as cracks are completely eliminated before transferring to the next step;

[0077] Step 5, final rolling: the third ring blank is heated to 1050-1080°C in an electric furnace, and the holding time is: the effective thickness of the third ring blank × 6min / 10mm. The heated and held third ring blank is final rolled in a CNC radial axis ring rolling machine, and the forging deformation is controlled at 10%-15% to form a fourth ring blank. After rolling, shot peening and coloring inspection are carried out to ensure that defects such as cracks are completely eliminated before proceeding to the next step.

[0078] Step 6, subjecting the fourth ring blank to solution heat treatment and aging heat treatment to obtain a Haynes 242 forging.

[0079] The grain size test of Haynes 242 forgings of Examples 1-3 and Comparative Examples 1-3 was performed using an optical microscope. The standard method for mechanical property testing was ASTM E8 / E8M. The test results are shown in Tables 1 and 2 below.

[0080] Table 1 Mechanical properties test results of Haynes 242 forgings of Examples 1-3 and Comparative Examples 1-3

[0081]

[0082] Table 2 Grain size test results of Haynes 242 forgings of Examples 1-3 and Comparative Examples 1-3

[0083] project Grain size Standard requirements Uniform 4 or finer Example 1 Level 4.5 Example 2 Level 4.5 Comparative Example 1 5+7.5(20%), uneven Comparative Example 2 7.5+3 (60%), mixed crystal, and coarse crystal over 4 levels

[0084] From the mechanical property test results of the forgings, it can be seen that the Haynes242 forgings prepared using the parameters specified in the present invention have good mechanical properties. Although the forgings of Comparative Examples 1 and 2 also meet the mechanical property standards of forgings, the elongation and shrinkage after fracture of the forgings of Comparative Example 1 are close to the lower limit values ​​required by the standard, and the plastic extension strength and hardness of the forgings of Comparative Example 2 are close to the lower limit values ​​required by the standard. The microstructure diagrams of the forgings of Example 1-2 and Comparative Example 1-2 under a high-power microscope are shown in FIG. Figure 3-Figure 6As shown, the grain size of the Haynes242 forging prepared by the parameters specified in the present invention is relatively uniform, which is level 4.5. Although the grain size of the forging of Example 1 is fine, the structure is uneven. The forging of Example 2 is mixed crystal, and the coarse grain exceeds level 4, and the structure is uneven. The forgings of Examples 1 and 2 are uneven in structure, which is not conducive to the subsequent machining of the forgings and is easy to cause deformation of the parts.

[0085] For those skilled in the art, when understanding the solutions described in the specific embodiments of the present invention, they can refer to the conventional technical manuals in the field. At the same time, for the places where the above-mentioned terms appear, they can make appropriate understandings or adjustments for reference, and deduce the implementation of the same or similar technical solutions without paying any creative work.

[0086] The above embodiments describe only the basic principles, main features and / or advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and the invention content of the specification only describe the principles or specific cases of the present invention. Without departing from the essence of the innovative idea of ​​the present invention, the innovative scheme of the present invention may be subject to various changes and improvements, and these changes and improvements all fall within the scope of protection required by the present invention.

Claims

1. A method for forming a uniform Haynes 242 forging, comprising the following steps in sequence: blanking, upsetting and punching, rack expansion and flat end surface, rolling and heat treatment; characterized in that: During the upsetting and punching, the blank is heated to a first forging temperature, and the first forging temperature is 1020-1060°C; The blank is heated to the second forging temperature in the flat end surface of the horse frame expansion hole, the second forging temperature is 1020-1060°C, and the forging deformation is 10%-15%; The rolling includes pre-rolling and final rolling. During the pre-rolling, the steel is heated to a third forging temperature, which is 1020-1060° C. The steel is rolled at least once, and the deformation of each rolling is controlled at 10%-20%. The final rolling adopts a step heating method to heat the blank to the fourth forging temperature, the fourth forging temperature is 1030-1050° C., and the forging deformation is 10%-15%.

2. The forming method of a uniformly structured Haynes 242 forging according to claim 1, characterized in that: Cutting is to saw Haynes242 raw material according to certain specifications based on forging specifications and required surplus materials. The raw materials are bars with a diameter of Φ150mm~Φ300mm and a height-to-diameter ratio of 2.0~3.

5.

3. The forming method of a uniformly structured Haynes 242 forging according to claim 1, characterized in that: In the upsetting and punching step, the blank is heated to the first forging temperature, and the upsetting deformation is 20% to 50%; the diameter of the punch used is 1 / 3 to 1 / 2 of the diameter of the blank after upsetting.

4. The forming method of a uniformly structured Haynes 242 forging according to claim 3, characterized in that: In the upsetting and punching steps, closed upsetting and punching are adopted, and the upsetting ratio of the forging is 1.8 to 3.

5. The forming method of a uniformly structured Haynes 242 forging according to claim 1, characterized in that: The pre-rolling adopts multi-pass rolling, the number of passes is 2 to 4.

6. The forming method of a uniformly structured Haynes 242 forging according to claim 5, characterized in that: The rolling deformation in each round of pre-rolling is controlled at 10% to 15%.

7. The forming method of a uniformly structured Haynes 242 forging according to claim 1, characterized in that: The final rolling adopts a step heating method, which is: the ring billet is loaded into a heating furnace with a set temperature. When the temperature reaches 1070-1110°C, it is kept at 1070-1110°C for 40-75 minutes, then cooled to 1030-1050°C with the furnace, and kept at 1030-1050°C for 0-120 minutes.

8. The forming method of a uniformly structured Haynes 242 forging according to claim 1, characterized in that: The heat treatment method is: subjecting the Haynes242 alloy forging to a solution heat treatment at 1030-1090°C for a holding time of 30-100 minutes; and then subjecting the forging to an aging heat treatment at 600-700°C for a time of 40-60 hours.

9. A method for forming a uniformly structured Haynes 242 forging according to any one of claims 1 to 8, characterized in that: The forming method specifically comprises the following steps: Step 1, cutting: sawing the Haynes242 bar according to the specifications; Step 2, upsetting and punching: heating the Haynes242 bar to a first forging temperature of 1020-1060° C., upsetting and punching the heated and heat-insulated Haynes242 bar to form a first ring blank; Step 3, horse rack reaming flat end face: heating the first ring blank to a second forging temperature of 1020-1060° C., using a horse bar and a horse rack reaming device to reaming the hole, and controlling the forging deformation amount to 10%-15% to form a second ring blank; Step 4, pre-rolling: heating the second ring blank to a third forging temperature of 1020-1060° C., pre-rolling the heated and heat-insulated second ring blank through at least one fire, with the rolling deformation amount of each fire being controlled at 10%-15%, to form a third ring blank; Step 5, final rolling: heating the third ring blank by a step heating method, the step heating method is: loading the ring blank into a heating furnace with a set temperature, when the temperature reaches 1070-1110° C., heat preservation treatment is performed for 40-75 minutes, then the temperature is lowered to 1030-1050° C. with the furnace, and heat preservation treatment is performed for 0-120 minutes at 1030-1050° C., the third ring blank is final rolled, and the forging deformation is controlled at 10%-15% to form a fourth ring blank; Step 6, subjecting the fourth ring blank to heat treatment to obtain a Haynes 242 forging.

10. A uniform Haynes 242 forging, characterized in that: The forging is prepared by the forming method of a uniformly structured Haynes 242 forging as described in any one of claims 1 to 9.

Images