Process for regulating the size and morphology of carbides in the interior of a sheet of stellite 6b alloy

Abstract

The present application relates to the technical field of high-temperature alloy material, in particular to a process for regulating and controlling the size and morphology of carbide in Stellite 6B alloy plate. The process comprises the following steps: multi-union melting of Stellite 6B alloy, high-temperature homogenization treatment, hot rolling, temperature control heat treatment, pickling and other processes. The carbide in the Stellite 6B alloy plate prepared by the process is mainly spherical, with a size of 3-10 μm, and is dispersedly distributed in the grain boundary and the grain of the alloy, thereby realizing the optimized matching of the strength and plasticity of the Stellite 6B alloy, and the wear resistance is more excellent, and the use requirements of wear resistance and long service life of the material are further met.

Description

Technical Field

[0001] This invention relates to the field of high-temperature alloy materials technology, and more specifically, to a process for controlling the size and morphology of carbides inside Stellite 6B alloy plates. Background Technology

[0002] Stellite 6B alloy sheet is a cobalt-based superalloy sheet with cobalt as the main element. Its typical composition is cobalt-30Cr-4.5W-1.2C (Co-30Cr-4.5W-1.2C). It is manufactured into sheet form through casting or machining processes and possesses high density, high melting point, and excellent high-temperature strength. Its superior high-temperature wear resistance, thermal fatigue resistance, and corrosion resistance make it a core material for critical high-temperature wear-resistant components in aerospace, chemical, hot-dip galvanizing, and mold industries. The core performance of this alloy lies in its carbide-dominated strengthening mechanism; therefore, the content, size, morphology, and distribution of carbides directly determine the final service performance and formability of the sheet.

[0003] Currently, the preparation of sheet metal aimed at leveraging the superior properties of Stellite 6B alloy generally faces prominent contradictions arising from the inherent characteristics of the alloy: on the one hand, the alloy relies on high-hardness, high-volume-fraction carbides such as M23C6 to ensure wear resistance; on the other hand, these brittle carbides precipitated along grain boundaries and distributed in a lath-like pattern are prone to becoming crack initiation points during hot working, resulting in difficulties in sheet metal forming and low yield.

[0004] In-depth research into its solidification and phase transformation processes reveals that the root of this contradiction lies in the formation and evolution mechanism of carbides. During solidification, primary MC and M7C3 carbides precipitate sequentially. Among them, the metastable M7C3 transforms in situ into stable M23C6 during cooling via a reaction (23M7C3→7M23C6+27C), mainly forming a lath-like eutectic structure along grain boundaries. This inherent precipitation path makes it difficult to optimize the morphology and distribution of carbides.

[0005] Therefore, how to effectively control the size, morphology and distribution of carbides, especially M23C6, through innovative process interventions while ensuring the high wear resistance of the alloy, in order to improve the forging formability of the alloy and enhance the overall performance and reliability of the plate, has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0006] The purpose of this invention is to solve the prominent contradiction in the preparation of Stellite 6B alloy plates, which is caused by the lath-like precipitation of high-hardness carbides along the grain boundaries, resulting in easy cracking during hot working, difficult forming, and low yield. Existing processes have limited ability to control the size, morphology and distribution of carbides, are ineffective and costly, and are difficult to significantly improve the forgeability and overall service reliability of the alloy while maintaining its excellent high-temperature wear resistance and corrosion resistance.

[0007] The purpose of this invention is to provide a process for controlling the size and morphology of carbides inside Stellite 6B alloy plates. Through multi-stage synergistic control, the distribution of carbides is optimized, thereby significantly improving the hot workability, mechanical properties and service reliability of the alloy while ensuring its inherent high wear resistance and corrosion resistance.

[0008] To achieve the above objectives, the present invention aims to provide a process for controlling the size and morphology of carbides inside Stellite 6B alloy plates, comprising the following steps:

[0009] Step S1: Prepare alloy ingots using a dual process of vacuum induction melting and vacuum arc remelting;

[0010] The ingots are placed in a high-temperature furnace for high-temperature homogenization treatment, and then cooled with the furnace.

[0011] Step S2: Use a high-speed forging machine to forge the ingot into a slab with dimensions and shape that meet the requirements of subsequent rolling. Then, mill or grind the surface of the slab to remove surface defects.

[0012] Subsequently, the slab is cut into sections, and then the slab is hot rolled in multiple passes to an intermediate thickness of 10-20mm.

[0013] Step S3: Perform a two-stage temperature-controlled heat treatment on the plate that has reached the intermediate thickness.

[0014] After temperature-controlled heat treatment, the sheet metal is immediately subjected to large deformation rolling, and rolled directly to the target thickness of the finished product in one go;

[0015] Step S4: Anneal the treated sheet material;

[0016] The annealed sheet is cut to the specified size, and then the surface oxide scale is removed to obtain the finished sheet.

[0017] As a further improvement to this technical solution, in step S1, vacuum arc remelting is carried out under a vacuum degree of less than 1 Pa, and the melting rate is precisely controlled at 2-4 kg / min during the stable melting stage.

[0018] As a further improvement to this technical solution, in step S1, the process parameters for homogenization treatment are 1180-1200℃ for 4-6 hours.

[0019] As a further improvement to this technical solution, in step S2, the multi-pass hot rolling involves heating the slab to 1170-1190℃ and holding it at that temperature for 30-60 minutes, followed by hot rolling.

[0020] Furthermore, during the entire multi-pass hot rolling process, when the plate temperature is below 1000℃, it is returned to the furnace for reheating to the specified temperature and held for 5-15 minutes before the next rolling pass is performed. This process is repeated until the plate is rolled to the intermediate thickness.

[0021] As a further improvement to this technical solution, in step S3, the two-stage temperature-controlled heat treatment involves holding the plate at 1190-1210℃ for 30-60 minutes, then lowering the temperature to 1100-1140℃ and holding it at that temperature for another 20-40 minutes.

[0022] Furthermore, immediately after temperature-controlled heat treatment, the sheet is subjected to rolling with a large deformation of 30-35% per pass.

[0023] As a further improvement to this technical solution, in step S4, the annealing process parameters are: holding at 1200-1240℃ for 10-15 minutes, followed by shutting down the furnace and cooling to room temperature.

[0024] As a further improvement to this technical solution, in step S4, pickling solution is used to remove the surface oxide scale, and after pickling, the surface is thoroughly rinsed with water and dried.

[0025] Preferably, the pickling solution is composed of: 50-70 g / L hydrochloric acid + 60-70 g / L hydrogen peroxide + 10-20 g / L hydrofluoric acid, with the balance being water.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] In the process of controlling the size and morphology of carbides inside Stellite 6B alloy plates, a two-stage temperature-controlled heat treatment of high-temperature reversible transformation and medium-temperature restabilization is used to actively induce a reversible phase transformation in some M23C6 carbides, effectively refining the carbide phase and improving its distribution morphology. Immediately afterwards, a large deformation rolling of 30-35% per pass is applied to thoroughly break up the potential network carbide structure through strong plastic deformation, forcing it to disperse. Finally, a short-time high-temperature annealing at 1200-1240℃ is used to further spheroidize and stabilize the carbides, and distribute them evenly in the matrix.

[0028] This invention, through the sequential synergy of phase transformation induction, large deformation crushing, and high-temperature spheroidization, deeply couples units such as smelting, hot working, and heat treatment. This not only achieves precise control over the morphology and distribution of carbides, but also simultaneously overcomes the industry bottlenecks in traditional processes, such as easy cracking during hot working, low yield, and difficulty in further improving wear resistance due to poor carbide distribution. This provides a technical path with controllable microstructure, excellent performance, and economic feasibility for the stable preparation of high-performance Stellite 6B alloy plates. Attached Figure Description

[0029] Figure 1This is a process flow diagram of the present invention;

[0030] Figure 2 This is a schematic diagram of the microstructure of the Stellite 6B alloy sheet prepared according to the present invention. Figure 1 ;

[0031] Figure 3 This is a schematic diagram of the microstructure of the Stellite 6B alloy sheet prepared according to the present invention. Figure 2 . Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] High-temperature alloys typically have complex compositions. Appropriate processing techniques can control the quantity and morphology of precipitated phases, thereby optimizing the alloy microstructure and ultimately improving material properties. Stellite 6B is a cobalt-based, carbide-strengthened high-temperature alloy. Besides cobalt, its composition includes nickel, chromium, tungsten, carbon, and small amounts of molybdenum, niobium, tantalum, titanium, and iron. This alloy possesses excellent high-temperature performance and wear resistance, while also exhibiting oxidation and corrosion resistance. It is widely used in aerospace, chemical, hot-dip galvanizing, instrumentation, and mold industries, commonly used in the manufacture of high-temperature, high-pressure valves, fluid valve seats, bearings, guide rollers, extrusion dies, as well as saw teeth, spiral push rods, screws, lead screws, and fiber cutters—various components operating in high-temperature, wear-resistant, and corrosion-resistant environments.

[0034] Unlike nickel-based and iron-based superalloys, Stellite 6B primarily relies on carbides for strengthening. Due to the high hardness of the carbides and their distribution within the relatively soft cobalt matrix, the alloy exhibits significant wear resistance. Under high-temperature loads and sliding conditions, adhesive wear occurs at the contact surfaces between the alloy and mating parts, forming an oxide film. This film slows heat conduction in the contact area and reduces subsurface softening, further enhancing wear resistance. Even at high temperatures, Stellite 6B maintains a high hardness of 350–500 HV, demonstrating excellent wear resistance, thermal fatigue resistance, and corrosion resistance, making it a key material for high-temperature wear-resistant applications. Clearly, the content, size, morphology, and distribution of carbides have a significant impact on the forgeability and wear resistance of the alloy and its components.

[0035] Carbon-containing cobalt-based superalloys precipitate various primary carbides during solidification, such as MC, M7C3, M23C6, and M6C. Under long-term high-temperature use conditions, these primary carbides further decompose and degrade. Stellite 6B alloy has a carbon content exceeding 1 wt%. Studies show its solidification process is as follows: above 1330℃, it is in a fully liquid state; below this temperature, austenite begins to precipitate; with further cooling to 1290℃, primary carbides MC precipitate directly from the liquid phase; at 1240℃, the liquid phase completely disappears, and the solidified structure consists of austenite and primary carbides M7C3; at a further decrease to 1080℃, the precipitation of M7C3 reaches its peak. M7C3 has an orthorhombic structure and is a metastable phase; as the temperature decreases, it transforms in situ into the face-centered cubic structure of M23C6, completing the transformation at 1000℃. During long-term high-temperature service, some M23C3 can continue to degrade into M6C carbides. The content of carbides such as M23C6 and M6C in Stellite 6B can reach 10%. While this high carbide content ensures excellent wear resistance, the carbides are also prone to becoming crack initiation points during hot working, leading to easy cracking during forging and rolling. Therefore, this alloy is difficult to hot work and form. Research shows that the reaction formula for the decomposition of M7C3 to form M23C6 in Stellite 6B is: 23M7C3→7M23C6+27C. The generated M23C6 mainly precipitates along grain boundaries, alternating with the austenite matrix in lath-like forms to form a eutectic structure. The carbon released in the reaction combines with chromium to form Cr23C6.

[0036] Although previous studies have covered the effects of composition and heat treatment on the microstructure and properties of cobalt-based superalloys, current research on the control of carbide size and morphology in Stellite 6B alloy wear-resistant plates is still relatively limited.

[0037] Therefore, regarding the problems encountered in the production of Stellite 6B alloy plates used in chemical, nuclear power, and major equipment industries, such as easy cracking, uneven carbide distribution, and abnormal morphology, which affect the service life of the plates, please refer to [link / reference needed]. Figure 1 As shown, the purpose of this invention is to provide a process for controlling the size and morphology of carbides inside Stellite 6B alloy plates, including the following steps:

[0038] Step S1:

[0039] (1) Multi-stage melting: First, alloy ingots are prepared using a dual process of vacuum induction melting (VIM) and vacuum arc remelting (VAR). Vacuum induction melting ensures precise proportioning and initial purification of alloying elements; subsequent vacuum arc remelting is carried out under vacuum conditions below 1 Pa, with the melting rate precisely controlled at 2-4 kg / min during the stable melting stage. This step aims to further remove gases and low-melting-point impurities, obtaining dense ingots with uniform composition and few metallurgical defects, laying the foundation for subsequent microstructure control.

[0040] (2) Homogenization treatment: The ingot is placed in a high-temperature furnace for high-temperature homogenization treatment. The process parameters are 1180-1200℃ and held for 4-6 hours, followed by furnace cooling. The core purpose of this step is twofold: First, to promote the partial dissolution or passivation and spheroidization of the coarse, skeletal primary carbides M7C3 distributed along the grain boundaries in the as-cast structure, so as to enhance the grain boundary bonding strength, improve the alloy plasticity, and effectively prevent cracking during subsequent billet forging; Second, to eliminate residual stress inside the ingot.

[0041] Step S2:

[0042] (3) Forging: The homogenized ingot is forged using a high-speed forging machine to form a slab with dimensions and shape that meet the requirements of subsequent rolling, thereby achieving initial densification and deformation of the microstructure.

[0043] (4) Machining: The surface of the forged slab is milled or ground to thoroughly remove surface defects such as oxide scale, pits, and inclusions. Subsequently, the slab is cut into pieces to obtain regular dimensions suitable for the rolling process.

[0044] (5) Multi-pass hot rolling: The slab is heated to 1170-1190℃ and held for 30-60 minutes, then hot rolled. Throughout the multi-pass rolling process, the plate temperature is strictly monitored. If the plate temperature drops below 1000℃, it is immediately returned to the furnace for reheating to the specified temperature and held for 5-15 minutes before the next rolling pass. This process is repeated until the plate is rolled to an intermediate thickness of 10-20 mm. This temperature-controlled rolling stage aims to avoid a surge in deformation resistance and the risk of cracking at low temperatures.

[0045] Step S3:

[0046] (6) Temperature-controlled heat treatment: A key two-stage temperature-controlled heat treatment is performed on the plate that has reached the intermediate thickness: first, it is held at 1190-1210℃ for 30-60 minutes, then the temperature is precisely reduced to 1100-1140℃ and held for another 20-40 minutes, after which it is quickly removed from the furnace for large deformation rolling. The core mechanism of this heat treatment lies in using phase transformation to regulate carbides: at a high temperature of 1200℃, some stable face-centered cubic M23C6 carbides will inversely transform into metastable orthogonal M7C3; then, during the intermediate temperature holding at 1120℃, this part of M7C3 will partially transform back into M3C6. This cyclic process refines the carbide phase, creating favorable microstructure conditions for subsequent large deformation.

[0047] (7) Rolling with large deformation

[0048] After temperature-controlled heat treatment, the sheet is immediately subjected to rolling with a large deformation of 30-35% per pass, directly rolling to the target thickness in one pass. The main purpose of the large deformation is to fully break down any remaining continuous or network carbide structure, forcing the carbides to disperse in the matrix; at the same time, it eliminates the notch sensitivity of the material through strong plastic deformation and significantly improves the overall mechanical properties.

[0049] Step S4:

[0050] (8) High-temperature annealing: The rolled finished sheet undergoes final high-temperature annealing at 1200-1240℃ for 10-15 minutes, followed by furnace cooling to room temperature (air cooling). This step aims to further spheroidize and stabilize the carbides (mainly M23C6, with a small amount of M7C3) through short-term high-temperature diffusion, and to distribute them evenly at grain boundaries and within grains. The final result is a carbide microstructure with a size of 3-10 micrometers, predominantly spherical and dispersed, thus achieving an optimized balance between alloy strength and plasticity.

[0051] (9) Pickling; Cut the annealed sheet to the specified size and remove the surface oxide scale using a pickling solution with a specific ratio. The pickling solution consists of: 50-70 g / L hydrochloric acid + 60-70 g / L hydrogen peroxide + 10-20 g / L hydrofluoric acid, with the balance being water. After pickling, rinse thoroughly with clean water and air dry.

[0052] (10) Inspection: Conduct comprehensive mechanical property tests (such as hardness and strength) and microstructure analysis (such as carbide morphology, distribution and size statistics) on the finished Stellite 6B alloy plates after final processing to ensure that all indicators meet the requirements of product design and end application.

[0053] The following specific embodiments will further illustrate the process for controlling the size and morphology of carbides inside Stellite 6B alloy plates provided by the present invention.

[0054] Example 1

[0055] Step S1: First, an alloy ingot is prepared using a dual process of vacuum induction melting followed by vacuum arc remelting. Vacuum induction melting ensures precise alloy element proportions and preliminary purification; subsequent vacuum arc remelting is carried out under a vacuum of 0.1 Pa, with the melting rate precisely controlled at 2 kg / min during the stable melting stage. The ingot is then placed in a high-temperature furnace for high-temperature homogenization treatment, with the process parameters being 1180℃ and held for 6 hours, followed by furnace cooling.

[0056] Step S2: The homogenized ingot is forged using a high-speed forging mill into a slab with dimensions and shape meeting the requirements of subsequent rolling. The surface of the forged slab is then milled or ground to thoroughly remove surface defects such as oxide scale, pits, and inclusions. Subsequently, the slab is cut into sections to obtain regular dimensions suitable for the rolling process. The slab is heated to 1170℃ and held for 60 minutes, then hot-rolled. Throughout the multi-pass rolling process, the plate temperature is strictly monitored. If the plate temperature drops below 1000℃, it is immediately reheated to the specified temperature and held for 15 minutes before the next rolling pass. This process is repeated until the plate is rolled to an intermediate thickness of 20mm.

[0057] Step S3: Perform a critical two-stage temperature-controlled heat treatment on the plate that has reached the intermediate thickness: First, hold at 1190℃ for 60 minutes, then precisely reduce the temperature to 1110℃ and hold for another 30 minutes, after which it is quickly removed from the furnace for large deformation rolling. Immediately after the temperature-controlled heat treatment, apply large deformation rolling of 30% per pass to the plate, directly rolling it to the target finished thickness in one pass.

[0058] Step S4: Perform final high-temperature annealing on the rolled finished sheet material. The process parameters are: hold at 1200℃ for 10 minutes, then turn off the furnace and cool to room temperature (air cooling). Cut the annealed sheet material to the specified size and remove the surface oxide scale using a pickling solution with a specific ratio. The pickling solution composition is: 50g / L hydrochloric acid + 60g / L hydrogen peroxide + 20g / L hydrofluoric acid, with the balance being water. After pickling, rinse thoroughly with clean water and air dry.

[0059] Example 2

[0060] Step S1: First, an alloy ingot is prepared using a dual process of vacuum induction melting followed by vacuum arc remelting. Vacuum induction melting ensures precise alloy element proportions and preliminary purification; subsequent vacuum arc remelting is carried out under a vacuum of 0.3 Pa, with the melting rate precisely controlled at 4 kg / min during the stable melting stage. The ingot is then placed in a high-temperature furnace for high-temperature homogenization treatment, with the process parameters being 1200℃ and held for 4 hours, followed by furnace cooling.

[0061] Step S2: The homogenized ingot is forged using a high-speed forging mill into a slab with dimensions and shape meeting the requirements of subsequent rolling. The surface of the forged slab is then milled or ground to thoroughly remove surface defects such as oxide scale, pits, and inclusions. Subsequently, the slab is cut into sections to obtain regular dimensions suitable for the rolling process. The slab is heated to 1190℃ and held for 30 minutes, then hot-rolled. Throughout the multi-pass rolling process, the plate temperature is strictly monitored. When the plate temperature drops below 1000℃, it is immediately reheated to the specified temperature and held for 15 minutes before the next rolling pass. This process is repeated until the plate is rolled to an intermediate thickness of 10mm.

[0062] Step S3: Perform a critical two-stage temperature-controlled heat treatment on the plate that has reached the intermediate thickness: First, hold at 1200℃ for 60 minutes, then precisely reduce the temperature to 1120℃ and hold for another 30 minutes, after which it is quickly removed from the furnace for large deformation rolling. Immediately after the temperature-controlled heat treatment, apply large deformation rolling of 35% per pass to the plate, directly rolling it to the target thickness of the finished product in one pass.

[0063] Step S4: Perform final high-temperature annealing on the rolled finished sheet material. The process parameters are: hold at 1240℃ for 15 minutes, then turn off the furnace and cool to room temperature (air cooling). Cut the annealed sheet material to the specified size and remove the surface oxide scale using a pickling solution with a specific ratio. The pickling solution composition is: 70g / L hydrochloric acid + 70g / L hydrogen peroxide + 20g / L hydrofluoric acid, with the balance being water. After pickling, rinse thoroughly with clean water and air dry.

[0064] In summary, this invention addresses the problems of easy cracking and low yield during hot working of Stellite 6B alloy due to poor carbide distribution in plate preparation. It proposes a composite process method that can precisely control the size, morphology, and distribution of carbides within the alloy, aiming to meet the stringent requirements of high wear resistance and long service life for its components. Specifically, this invention integrates multi-stage melting and purification, high-temperature homogenization, temperature-controlled multi-pass hot rolling, phase transformation-induced heat treatment, large deformation rolling, and final high-temperature annealing, constructing a closed-loop process for full-process control of carbide "melting-precipitation-fragmentation-spheroidization". The key lies in the creative use of a two-stage temperature-controlled heat treatment of "high-temperature reverse transformation + medium-temperature restabilization" to actively intervene in the carbide phase transformation path. At a high temperature stage of approximately 1200℃, some stable M23C6 carbides are reverse-transformed into metastable M7C3; subsequently, at a medium temperature stage of approximately 1120℃, this portion of M7C3 partially re-transforms into M23C6. This controlled phase transformation cycle effectively refines the carbide phase, creating favorable initial microstructure conditions for the subsequent complete disruption of its network distribution through large deformation rolling.

[0065] In terms of microstructure and performance control, this process establishes a synergistic mechanism of "thermal-mechanical-phase transformation". Large deformation rolling is carried out immediately after a specific phase transformation window, using intense plastic deformation to force the carbide to disperse and eliminate the material's notch sensitivity; the final high-temperature short-time annealing promotes further spheroidization and stabilization of the carbides. This sequential and precise coordination of force and heat transforms material preparation from passive deformation processing to active microstructure design.

[0066] This invention is based on the material properties of high-carbon Stellite 6B alloy, and its core lies in the design of a synergistic process integrating temperature-controlled heat treatment and large-deformation rolling. By precisely controlling the heat treatment temperature and holding time, and planning a specific rolling deformation program, the smooth progress of the sheet preparation process is effectively ensured. This process promotes the formation of an ideal combination within the sheet, dominated by stable face-centered cubic M23C6 carbides and supplemented by a small amount of orthorhombic M7C3 carbides. See the microstructure of the sheets prepared in Examples 1-2 (see...). Figure 2-3 As shown in the figure, after this temperature-controlled heat treatment, the morphology of the carbides was optimized to be spherical, with the size controlled between 3-10 μm, and a uniformly dispersed distribution was achieved at the grain boundaries and within the grains. This successfully avoided the formation of harmful network carbides, thus achieving an optimized match between the alloy's strength and plasticity.

[0067] Compared with traditional rolling processes, this invention not only significantly improves the wear resistance of Stellite 6B alloy plates, but also greatly increases their yield.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for controlling the size and morphology of carbides inside Stellite 6B alloy plates, characterized in that, Includes the following steps: Step S1: Prepare alloy ingots using a dual process of vacuum induction melting and vacuum arc remelting; The ingots are placed in a high-temperature furnace for high-temperature homogenization treatment, and then cooled with the furnace. Step S2: Use a high-speed forging machine to forge the ingot into a slab with dimensions and shape that meet the requirements of subsequent rolling. Then, mill or grind the surface of the slab to remove surface defects. Subsequently, the slab is cut into sections, and then the slab is hot rolled in multiple passes to an intermediate thickness of 10-20mm. Step S3: Perform a two-stage temperature-controlled heat treatment on the plate that has reached the intermediate thickness. After temperature-controlled heat treatment, the sheet metal is immediately subjected to large deformation rolling, and rolled directly to the target thickness of the finished product in one go; Step S4: Anneal the treated sheet material; The annealed sheet is cut to the specified size, and then the surface oxide scale is removed to obtain the finished sheet. In step S1, the process parameters for homogenization treatment are: heat preservation at 1180-1200℃ for 4-6 hours. In step S3, the two-stage temperature-controlled heat treatment involves holding the plate at 1190-1210℃ for 30-60 minutes, then lowering the temperature to 1100-1140℃ and holding it at that temperature for another 20-40 minutes. Immediately after temperature-controlled heat treatment, the sheet metal is subjected to rolling with a large deformation of 30-35% per pass. In step S4, the annealing process parameters are: holding at 1200-1240℃ for 10-15 minutes, followed by cooling the furnace to room temperature after power is turned off.

2. The process for controlling the size and morphology of carbides inside Stellite 6B alloy plates according to claim 1, characterized in that: In step S1, vacuum arc remelting is carried out under a vacuum level of less than 1 Pa, and the melting rate is precisely controlled at 2-4 kg / min during the stable smelting stage.

3. The process for controlling the size and morphology of carbides inside Stellite 6B alloy plates according to claim 1, characterized in that: In step S2, the multi-pass hot rolling involves heating the slab to 1170-1190℃ and holding it at that temperature for 30-60 minutes before hot rolling.

4. The process for controlling the size and morphology of carbides inside Stellite 6B alloy plates according to claim 3, characterized in that: During the entire multi-pass hot rolling process, when the plate temperature is below 1000℃, it is returned to the furnace for reheating to the specified temperature and held for 5-15 minutes before the next rolling pass. This process is repeated until the plate is rolled to the intermediate thickness.

5. The process for controlling the size and morphology of carbides inside Stellite 6B alloy plates according to claim 1, characterized in that: In step S4, pickling solution is used to remove the surface oxide scale, and after pickling, the surface is thoroughly rinsed with water and dried.

6. The process for controlling the size and morphology of carbides inside Stellite 6B alloy plates according to claim 5, characterized in that: The pickling solution consists of: 50-70 g / L hydrochloric acid + 60-70 g / L hydrogen peroxide + 10-20 g / L hydrofluoric acid, with the remainder being water.

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