Preparation method of Ni-Cr-Fe-based high-temperature alloy radial forging bar

Abstract

The invention relates to the technical field of high-temperature alloys, and provides a preparation method of a Ni-Cr-Fe-based high-temperature alloy radial forging bar, which specifically comprises the following steps: S1, carrying out radial forging on a Ni-Cr-Fe-based high-temperature alloy blank; s2, the high-temperature alloy bar obtained after radial forging is heated and then subjected to heat preservation and standing treatment; s3, the obtained high-temperature alloy bar is subjected to pre-deformation shaping; s4, the obtained high-temperature alloy bar is subjected to low-temperature solid solution preheating treatment; and S5, the obtained high-temperature alloy bar is firstly subjected to solution treatment and then subjected to two-stage aging treatment, and the Ni-Cr-Fe-based high-temperature alloy radial forging bar is obtained. According to the method, in the preparation process of the radial forging bar, through a series of steps of constant-temperature standing, pre-deformation shaping, low-temperature solid solution and multi-stage standard heat treatment, the structure uniformity and precipitated phase precipitation of the Ni-Cr-Fe-based high-temperature alloy radial forging finished bar are controlled, and the high-stability structure and bar quality of the Ni-Cr-Fe-based high-temperature alloy are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature alloys, and in particular to a method for preparing a Ni-Cr-Fe based high-temperature alloy radial forging bar. Background Art

[0002] High-temperature alloy large bar products are typically produced using a combination of rapid forging and radial forging. Radial forging, due to its rapid deformation speed and minimal temperature drop, allows forging at lower billet heating temperatures. By adjusting the elongation coefficient and step size of each pass, varying forgeability can be achieved, controlling the bar's temperature rise, and easily achieving a fine-grained finished product with relatively uniform microstructure across all parts. This facilitates achieving a fine-grained structure, thereby improving the alloy's overall performance.

[0003] The structure and properties of Ni-Cr-Fe-based superalloys are extremely sensitive to thermal processing technology, which makes their thermal processing range narrow and the control of microstructure uniformity difficult. The conventional radial forging process for preparing Ni-Cr-Fe-based superalloys often results in uneven microstructure control and uncontrolled precipitation of precipitated phases. Therefore, the development of a more stable radial forging process with controlled microstructure uniformity can improve the quality of Ni-Cr-Fe-based superalloys and greatly reduce the scrap rate of Ni-Cr-Fe-based superalloy products. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a method for preparing Ni-Cr-Fe based high temperature alloy radial forging bars. The high temperature alloy bars prepared in the present application can achieve control of the uniformity of the structure and precipitation phase.

[0005] In view of this, the present application provides a method for preparing a Ni-Cr-Fe based high temperature alloy radial forging bar, comprising the following steps:

[0006] S1. Radial forging a Ni-Cr-Fe based high temperature alloy billet;

[0007] S2, heating the high-temperature alloy bar after radial forging and then keeping it at a temperature-insulated state;

[0008] S3, pre-deforming the high-temperature alloy rod obtained in step S2, wherein the pre-deforming frequency is 150-200 times / min, the shaping rate is 1.0-3.0 m / min, and the shaping deformation is less than 10%;

[0009] S4, performing a low-temperature solid solution preheating treatment on the high-temperature alloy rod obtained in step S3;

[0010] S5. The high-temperature alloy rod obtained in step S4 is first subjected to a solution treatment and then to a two-stage aging treatment to obtain a Ni-Cr-Fe based high-temperature alloy radial forging rod.

[0011] In some specific embodiments, in step S1, the radial forging is performed by heating in one pass and deforming in multiple passes.

[0012] In some specific embodiments, in step S1, the temperature of the first heating is 1000-1050° C., and the deformation of the radial forging is 30-50%.

[0013] In some specific embodiments, in step S2, the heating temperature is 990-1010° C., and the holding time is 60-200 min.

[0014] In some specific embodiments, in step S3, the shaping frequency is 160-180 times / min, the shaping rate is 1.5-2.5 m / min, and the shaping deformation is 5-7%.

[0015] In some specific embodiments, in step S4, in the low-temperature solid solution preheating treatment, the heating temperature is 950-980° C., the holding time is 60-90 min, and the cooling method is air cooling.

[0016] In some specific embodiments, in step S5, the temperature of the solution treatment is 900-1000°C.

[0017] In some specific embodiments, in step S5, the primary aging treatment temperature is 700-750° C., and the time is 6-10 h, and the secondary aging treatment temperature is 600-650° C., and the time is 6-10 h.

[0018] In some specific embodiments, the composition of the Ni-Cr-Fe based high temperature alloy, in percentage by mass, includes: Ni: 50-55%, Cr: 17-21%, Nb: 5-5.5%, Mo: 2.8-3.3%, Al: 0.2-0.8%, Ti: 0.65-1.15%, and Fe: balance.

[0019] In some specific embodiments, the size of the Ni-Cr-Fe based high temperature alloy radial forging bar is φ200~φ400 mm.

[0020] The present application provides a method for preparing a Ni-Cr-Fe based high temperature alloy radial forging bar, which firstly subjects the Ni-Cr-Fe based high temperature alloy billet to radial forging main deformation, and then subjects it to constant temperature static state with heating and heat preservation. The combination of radial forging main deformation and constant temperature static state promotes the full completion of recrystallization of the Ni-Cr-Fe based high temperature alloy billet and uniform radial forging structure. Then, the billet is subjected to a pre-forming micro-shaping treatment to obtain built-in stress. Finally, the billet is subjected to low temperature solid solution + multi-stage solid solution and aging treatment to further stabilize the radial forging structure and obtain uniform grain control and uniform precipitation phase precipitation control, thereby realizing the uniformity control of the structure and precipitation phase of the Ni-Cr-Fe based high temperature alloy bar. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 Figure 1 is a metallographic photograph of a Ni-Cr-Fe-based superalloy rod prepared in Example 1 of the present invention. Figure a is a metallographic photograph of the center of the rod, Figure b is a metallographic photograph of the rod within the radius range, and Figure c is a metallographic photograph of the edge of the rod.

[0022] Figure 2 Figure 1 is a metallographic photograph of a Ni-Cr-Fe-based superalloy rod prepared in Comparative Example 1 of the present invention. Figure a is a metallographic photograph of the center of the rod, Figure b is a metallographic photograph of the radius of the rod, and Figure c is a metallographic photograph of the edge of the rod.

[0023] Figure 3 Figure 2 is a metallographic photograph of a Ni-Cr-Fe-based superalloy rod prepared in Example 2 of the present invention. Figure a is a metallographic photograph of the center of the rod, Figure b is a metallographic photograph of the rod within the radius, and Figure c is a metallographic photograph of the edge of the rod.

[0024] Figure 4 These are metallographic photographs of the Ni-Cr-Fe based high temperature alloy rod prepared in Comparative Example 2 of the present invention. Figure a is a metallographic photograph of the center of the rod, Figure b is a metallographic photograph of the radius range of the rod, and Figure c is a metallographic photograph of the edge of the rod. DETAILED DESCRIPTION

[0025] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0026] In order to improve the microstructure uniformity and phase precipitation control during the radial forging process of Ni-Cr-Fe-based high-temperature alloy bars, the present application provides a method for preparing Ni-Cr-Fe-based high-temperature alloy radial forging bars, which adopts a combination of constant temperature static + pre-deformation shaping + low-temperature solid solution + multi-stage standard heat treatment to achieve the microstructure uniformity and precipitation control of the radial forging bars, thereby improving the high-stability microstructure and bar quality of the Ni-Cr-Fe-based high-temperature alloy. Specifically, the embodiment of the present invention discloses a method for preparing Ni-Cr-Fe-based high-temperature alloy radial forging bars, comprising the following steps:

[0027] S1. Radial forging a Ni-Cr-Fe based high temperature alloy billet;

[0028] S2, heating the high-temperature alloy bar after radial forging and then keeping it at a temperature-insulated state;

[0029] S3, pre-deforming the high-temperature alloy rod obtained in step S2, wherein the pre-deforming frequency is 150-200 times / min, the shaping rate is 1.0-3.0 m / min, and the shaping deformation is less than 10%;

[0030] S4, performing a low-temperature solid solution preheating treatment on the high-temperature alloy rod obtained in step S3;

[0031] S5. The high-temperature alloy rod obtained in step S4 is first subjected to a solution treatment and then to a two-stage aging treatment to obtain a Ni-Cr-Fe based high-temperature alloy radial forging rod.

[0032] In the preparation process of Ni-Cr-Fe-based high-temperature alloy radial forging bar, the Ni-Cr-Fe-based high-temperature alloy billet is first radially forged. The Ni-Cr-Fe-based high-temperature alloy billet is specifically an intermediate billet for rapid forging of Ni-Cr-Fe-based high-temperature alloy. The preparation of the intermediate billet for rapid forging of Ni-Cr-Fe-based high-temperature alloy is well known to those skilled in the art and is not particularly limited in this application. The radial forging adopts a single-fire heating and multi-pass deformation method; the heating temperature is 1000-1050°C, and the deformation amount of the deformation is 30-50%. More specifically, the heating temperature is 1000-1020°C, and the deformation amount of the deformation is 35-43%. More specifically, the heating temperature is 1010-1020°C, and the deformation amount of the deformation is 38-40%.

[0033] This application then subjects the radially forged high-temperature alloy intermediate bar to a constant temperature static treatment, i.e., the radially forged intermediate bar is hot fed into a heating furnace, the furnace temperature is pre-set to 990-1010°C, and the bar is kept warm for 60-200 minutes to achieve recrystallization structure reconstruction of the radially forged bar structure, establish a distortion-free structure of the bar, and eliminate the forging stress of the bar; specifically, the holding time is 70-180 minutes, more specifically, the holding time is 90-150 minutes, and more specifically, the holding time is 100-120 minutes.

[0034] According to the present invention, after radial forging, the high-temperature alloy intermediate bar is subjected to constant temperature static treatment and then removed from the furnace for pre-deformation shaping, using high-frequency, slow, small-deformation radial forging shaping to establish uniform preset internal stress in the bar. The pre-deformation shaping frequency is 150-200 times / min, the shaping rate is 1.0-3.0 m / min, and the shaping deformation is less than 10%; specifically, the shaping frequency is 160-190 times / min, the shaping rate is 1.5-2.5 m / min, and the shaping deformation is 5-7%; more specifically, the shaping frequency is 170-180 times / min, the shaping rate is 1.5-2.0 m / min, and the shaping deformation is 5-6%; more specifically, the shaping rate is 1.7-1.8 m / min.

[0035] After completing the above-mentioned pre-deformation and shaping, the rod is subjected to low-temperature solid solution preheating treatment to control the precipitation of the precipitated phase. The temperature of the low-temperature solid solution preheating treatment is 950~980℃, the holding time is 60~90min, and the cooling method is air cooling. Specifically, the temperature of the low-temperature solid solution preheating treatment is 960~970℃, and the time is 70~80min.

[0036] The present application finally performs a multi-stage heat treatment, which specifically includes a solution treatment and a two-stage aging treatment to control the precipitation of the precipitated phase; the temperature of the solution treatment is 900-1000°C, the primary aging temperature of the aging treatment is 700-750°C, the time is 6-10h, and the secondary aging temperature is 600-650°C, and the time is 6-10h; specifically, the temperature of the solution treatment is 950-980°C, the primary aging temperature of the aging treatment is 720-740°C, the time is 7-8h, and the secondary aging temperature is 620-640°C, and the time is 7-8h.

[0037] In the method for preparing a Ni-Cr-Fe-based high-temperature alloy radial forging bar provided herein, the Ni-Cr-Fe-based high-temperature alloy comprises, by mass percentage, the following: Ni: 50-55%, Cr: 17-21%, Nb: 5-5.5%, Mo: 2.8-3.3%, Al: 0.2-0.8%, Ti: 0.65-1.15%, and Fe: the balance. Specifically, the Ni-Cr-Fe-based high-temperature alloy comprises, by mass percentage, the following: Ni: 51-53%, Cr: 18-20%, Nb: 5.2-5.4%, Mo: 2.9-3.1%, Al: 0.4-0.6%, Ti: 1.00-1.10%, and Fe: the balance. The preparation method provided herein can produce bars with a size of φ200-φ400 mm, specifically, φ250-φ300 mm.

[0038] The present application provides a preparation method of Ni-Cr-Fe based high temperature alloy radial forging bars, which adopts the radial forging main deformation + constant temperature static method to eliminate the forming stress of the radial forging bars and promote the full completion of recrystallization, solve the problem of uncontrolled grain structure of conventional radial forging products in post-forging heat treatment, and prepare a more uniform initial structure for structure regulation; the subsequent pre-forming and shaping process, through high-speed micro-deformation shaping, improves the surface quality of the product while uniformly generating residual stress inside the product, solves the problem of uneven stress distribution after conventional radial forging, which causes uneven grain growth; the subsequent low-temperature solution treatment can control the precipitation of the second phase, strengthen the grain size structure, stabilize the uniform grain structure, and solve the problem of uneven structure evolution in standard heat treatment after conventional forging. In summary, the bar material after the main deformation pass of radial forging in this application is subjected to constant temperature static treatment, which can eliminate the forging stress and complete the static recrystallization of the structure. After pre-deformation and shaping, a uniform preset internal stress of the bar material is established, and then a low-temperature solid solution preheat treatment is performed to control the pre-precipitation of the precipitated phase and stabilize the structure. Finally, a multi-stage standard heat treatment is completed to control the uniform precipitation of the precipitated phase and ensure the uniformity of the structure of the Ni-Cr-Fe based high-temperature alloy bar material.

[0039] In order to further understand the present invention, the preparation method of the Ni-Cr-Fe based high temperature alloy radial forging bar provided by the present invention is described in detail below with reference to the examples. The protection scope of the present invention is not limited by the following examples.

[0040] Example 1: A Ni-Cr-Fe based high temperature alloy bar product with a forging specification requirement of Φ250mm

[0041] Step 1: The main components of the Ni-Cr-Fe-based high-temperature alloy, in terms of mass percentage, include: Ni: 53.47%, Cr: 18.52%, Nb: 5.39%, Mo: 3.03%, Al: 0.59%, Ti: 1.02%, Fe: Bal. During the radial forging process, the radial forging process adopts single-fire heating and multi-pass deformation, the heating temperature is 1010°C ± 10°C, and the radial forging deformation is 40%;

[0042] Step 2: The intermediate bar obtained in step 1 is returned to the furnace hot and placed in a constant temperature static treatment, the furnace temperature is controlled at 1000℃±10℃, and after being heated, it is placed in a static insulation for 60 minutes;

[0043] Step 3: The intermediate bar obtained in step 2 is taken out of the furnace and transferred to the radial forging platform for hot pre-deformation shaping. The shaping frequency is 180 times / min, the shaping speed is 1.5m / min, and the shaping deformation is 5%.

[0044] Step 4: The rod obtained in step 3 is sent to a heating furnace for low-temperature solution preheating treatment. The furnace temperature is pre-set to 960°C ± 10°C. After the rod is heated, it is kept warm for 60 minutes and air-cooled.

[0045] Step 5: The rod obtained in step 4 is first subjected to a solution treatment at 980°C, and then subjected to a two-stage aging heat treatment at 720°C for 8h+620°C for 8h to control the precipitation of the precipitated phase.

[0046] Example 2: A Ni-Cr-Fe based high temperature alloy bar product with a forging specification requirement of Φ300mm

[0047] Step 1: The main components of the Ni-Cr-Fe-based high-temperature alloy, in terms of mass percentage, include: Ni: 53.10%, Cr: 18.11%, Nb: 5.21%, Mo: 3.09%, Al: 0.57%, Ti: 1.01%, and Fe: Bal. During the radial forging process, the radial forging process adopts single-fire heating and multi-pass deformation, the heating temperature is 1010°C ± 10°C, and the radial forging deformation is 38%;

[0048] Step 2: Return the intermediate bar obtained in step 1 to the furnace and place it in a constant temperature static treatment. The furnace temperature is controlled at 1000℃±10℃. After being heated, place it in a static temperature preservation state for 70 minutes.

[0049] Step 3: The bar obtained in step 2 is taken out of the furnace and transferred to the radial forging platform for hot pre-deformation shaping. The shaping frequency is 180 times / min, the shaping speed is 1.8m / min, and the shaping deformation amount is 6%.

[0050] Step 4: The rod obtained in step 3 is sent to a heating furnace for low-temperature solution preheating treatment. The furnace temperature is pre-set to 960°C ± 10°C. After the rod is heated, it is kept warm for 60 minutes and air-cooled.

[0051] Step 5: subject the rod obtained in step 4 to a solution treatment at 980°C, and then to a two-stage aging heat treatment at 720°C for 8h + 620°C for 8h to control the precipitation of the precipitated phase.

[0052] Comparative Example 1: A Ni-Cr-Fe based high temperature alloy bar product with a forging specification requirement of Φ250mm

[0053] Step 1: The main components of the Ni-Cr-Fe-based high-temperature alloy, in terms of mass percentage, include: Ni: 53.47%, Cr: 18.52%, Nb: 5.39%, Mo: 3.03%, Al: 0.59%, Ti: 1.02%, and Fe: Bal. During the radial forging process, the radial forging process adopts single-fire heating and multi-pass deformation, the heating temperature is 1010°C ± 10°C, and the main radial forging deformation is 35%;

[0054] Step 2: directly perform radial forging on the intermediate bar obtained in step 1, with a shaping frequency of 180 times / min, a shaping speed of 1.5 m / min, and a shaping deformation of 3%;

[0055] Step three, subjecting the rod obtained in step two to a solution treatment at 980°C, and then to a two-stage aging heat treatment at 720°C for 8h + 620°C for 8h to control the precipitation of the precipitated phase.

[0056] Comparative Example 2: A Ni-Cr-Fe based high temperature alloy bar product with a forging specification requirement of Φ300

[0057] Step 1: The main components of the Ni-Cr-Fe-based high-temperature alloy, in terms of mass percentage, include: Ni: 53.10%, Cr: 18.11%, Nb: 5.21%, Mo: 3.09%, Al: 0.57%, Ti: 1.01%, and Fe: Bal. During the radial forging process, the radial forging process adopts single-fire heating and multi-pass deformation, the heating temperature is 1010°C ± 10°C, and the main deformation amount of the radial forging is 38%;

[0058] Step 2: The intermediate bar obtained in step 1 is directly subjected to radial forging with a shaping frequency of 180 times / min, a shaping speed of 1.5 m / min, and a shaping deformation of 2%.

[0059] Step 3: The rod obtained in step 2 is first subjected to a solution treatment at 980°C, and then subjected to a two-stage aging heat treatment at 720°C for 8h+620°C for 8h to control the precipitation of the precipitated phase.

[0060] Figure 1 This is a metallographic photograph of the Ni-Cr-Fe based high temperature alloy rod prepared in Example 1 of the present invention; Figure 1It can be seen that the Ni-Cr-Fe based high temperature alloy rod prepared in Example 1 has a highly uniform grain structure with a step difference of less than 1 from the radius to the center, the surface grains are equiaxed, and the precipitated phases at the grain boundaries are continuously and evenly distributed.

[0061] Figure 2 This is a metallographic photograph of the Ni-Cr-Fe based high temperature alloy rod prepared in Comparative Example 1 of the present invention; Figure 2 It can be seen that the Ni-Cr-Fe based high temperature alloy rod prepared in Comparative Example 1 has individual large grains in the core, mixed crystals in the radius, poor grain structure uniformity, ultrafine grain areas at the edge, and poor distribution of precipitated phases.

[0062] Figure 3 This is a metallographic photograph of the Ni-Cr-Fe based high temperature alloy rod prepared in Example 2 of the present invention; Figure 3 It can be seen that the Ni-Cr-Fe-based high-temperature alloy rod prepared in Example 2 has a highly uniform grain structure with a level difference from the radius to the center of almost 0, an equiaxed distribution of surface grains, and a continuous and uniform distribution of precipitated phases at grain boundaries.

[0063] Figure 4 This is a metallographic photograph of the Ni-Cr-Fe based high temperature alloy rod prepared in Comparative Example 2 of the present invention; Figure 4 It can be seen that the radius of the Ni-Cr-Fe based high temperature alloy rod prepared in Comparative Example 2 has obvious mixed crystals, the grain structure uniformity from the center to the radius is poor, and the ultrafine grain area at the edge has poor distribution of precipitated phases.

[0064] The above embodiments are only intended to help understand the method and core concept of the present invention. It should be noted that, without departing from the principles of the present invention, a number of improvements and modifications may be made to the present invention by those skilled in the art, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

[0065] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a Ni-Cr-Fe based high temperature alloy radial forging bar, comprising the following steps: S1. Radial forging a Ni-Cr-Fe based high temperature alloy billet; S2, heating the high-temperature alloy bar after radial forging and then keeping it at a temperature-insulated state; S3, pre-deforming the high-temperature alloy rod obtained in step S2, wherein the pre-deforming frequency is 150-200 times / min, the shaping rate is 1.0-3.0 m / min, and the shaping deformation is less than 10%; S4, performing a low-temperature solid solution preheating treatment on the high-temperature alloy rod obtained in step S3; S5. The high-temperature alloy rod obtained in step S4 is first subjected to a solution treatment and then to a two-stage aging treatment to obtain a Ni-Cr-Fe based high-temperature alloy radial forging rod.

2. The preparation method according to claim 1, characterized in that In step S1, the radial forging is performed by heating in one pass and deforming in multiple passes.

3. The preparation method according to claim 2, characterized in that In step S1, the temperature of the first heating is 1000-1050° C., and the deformation of the radial forging is 30-50%.

4. The preparation method according to claim 1, characterized in that In step S2, the heating temperature is 990-1010° C., and the holding time is 60-200 min.

5. The preparation method according to claim 1, characterized in that In step S3, the shaping frequency is 160-180 times / min, the shaping rate is 1.5-2.5 m / min, and the shaping deformation is 5-7%.

6. The preparation method according to claim 1, characterized in that In step S4, in the low-temperature solid solution preheating treatment, the heating temperature is 950-980° C., the holding time is 60-90 min, and the cooling method is air cooling.

7. The preparation method according to claim 1, characterized in that In step S5, the temperature of the solution treatment is 900-1000°C.

8. The preparation method according to claim 7, characterized in that In step S5, the primary aging temperature of the aging treatment is 700-750° C., and the time is 6-10 hours, and the secondary aging temperature is 600-650° C., and the time is 6-10 hours.

9. The preparation method according to any one of claims 1 to 8, characterized in that The composition of the Ni-Cr-Fe based high temperature alloy, in terms of mass percentage, includes: Ni: 50-55%, Cr: 17-21%, Nb: 5-5.5%, Mo: 2.8-3.3%, Al: 0.2-0.8%, Ti: 0.65-1.15%, and Fe: balance.

10. The preparation method according to any one of claims 1 to 8, characterized in that The size of the Ni-Cr-Fe based high temperature alloy radial forging bar is φ200-φ400 mm.

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