A heat treatment method for improving corrosion performance of high-molybdenum tungsten nickel-based alloy plate

Abstract

The present application belongs to the field of metal material heat treatment, and discloses a heat treatment method for improving the corrosion performance of high-molybdenum tungsten nickel-based alloy plate. The method comprises the following steps: designing a heat treatment system according to the rolling compression ratio of the finished plate (finished plate thickness / blank thickness): when the compression ratio is less than or equal to 3, first heat preservation at 1200-1210 DEG C for 3 min, then cooling to 1180-1200 DEG C, and water cooling after heat preservation according to the plate thickness of 2 min / mm; when the compression ratio is 3-6, first heat preservation at 1210-1230 DEG C for 2-3 min, then cooling to 1180-1200 DEG C, and water cooling after heat preservation according to the plate thickness of 2 min / mm; when the compression ratio is greater than or equal to 6, first heat preservation at 1220-1230 DEG C for 2 min, then cooling to 1180-1200 DEG C, and water cooling after heat preservation according to the plate thickness of 2 min / mm. The present application solves the contradiction between high-melting-point precipitates and abnormal grain growth, makes the precipitates fully dissolve and controls the grain size, and significantly improves the comprehensive performance of the plate.

Description

Technical Field

[0001] This invention relates to the field of heat treatment technology for metallic materials, and specifically to a heat treatment method for improving the corrosion resistance of plates in high-molybdenum tungsten-nickel-based alloys. Background Technology

[0002] Nickel-based alloys are widely used in key fields such as petrochemicals, energy, environmental protection, and national defense due to their excellent high-temperature strength, good oxidation resistance, and corrosion resistance. Among them, high-molybdenum tungsten nickel-based alloys (Hastelloy alloys), represented by N10276, have excellent corrosion resistance, especially in oxidizing and reducing media, due to their high content of alloying elements such as molybdenum (Mo) and tungsten (W).

[0003] However, the production process of these alloys is complex and requires high quality. Significant technical challenges exist in the plate production process, especially in the heat treatment stage. Conventional solution heat treatment in existing technologies typically involves holding the material at a single temperature for an extended period. For high-molybdenum tungsten-nickel-based alloys, on the one hand, a large number of high-melting-point WC and MoC precipitates form in the microstructure. These precipitates require temperatures above 1200℃ for effective dissolution; insufficient dissolution will severely impair the corrosion resistance of the plate. On the other hand, holding the material at such high temperatures for extended periods can lead to abnormally coarse grain growth, potentially reaching a grain size of 00 grade. This not only significantly reduces the material's mechanical properties (such as yield strength and tensile strength) but also affects subsequent processing and forming.

[0004] Therefore, existing heat treatment processes cannot simultaneously meet the dual requirements of sufficient remelting of high-melting-point precipitates and effective control of grain size, resulting in large fluctuations in the corrosion performance data of high-molybdenum tungsten nickel-based alloy plates. It is difficult to achieve a good match between mechanical properties and corrosion performance, which seriously affects the long-term stable service of the product and the yield. Summary of the Invention

[0005] In view of the above problems, the present invention aims to solve the contradiction between the remelting of high-melting-point precipitates and abnormal grain growth during the heat treatment of high-molybdenum tungsten nickel-based alloy plates in the prior art, and to provide a heat treatment method to improve the corrosion resistance of high-molybdenum tungsten nickel-based alloy plates.

[0006] The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten nickel-based alloy plates according to embodiments of the present invention includes the following steps: A heat treatment process regime is designed and executed based on the rolling compression ratio of the finished plate: When the compression ratio is ≤3, the holding temperature of the first segment of the heat treatment curve is 1200-1210℃, the holding time is 3 min, then the temperature is lowered to 1180-1200℃, the holding time is 2 min / mm based on the plate thickness, followed by water cooling; When the compression ratio is between 3 and 6, the holding temperature of the first segment of the heat treatment curve is 1210-1230℃, the holding time is 2-3 min, then the temperature is lowered to 1180-1200℃, the holding time is 2 min / mm based on the plate thickness, followed by water cooling; When the compression ratio is ≥6, the holding temperature of the first segment of the heat treatment curve is 1220-1230℃, the holding time is 2 min, then the temperature is lowered to 1180-1200℃, the holding time is 2 min / mm based on the plate thickness, followed by water cooling. The rolling compression ratio of the finished plate is determined based on the ratio of the finished plate thickness to the billet thickness.

[0007] Furthermore, the composition of the high-molybdenum tungsten nickel-based alloy, by weight percentage, includes: C≤0.010%, Si≤0.08%, Mn≤1.00%, P≤0.040%, S≤0.030%, Cr 14.50-16.50%, Mo 15.00-17.00%, W 3.00-4.50%, Fe 4.00-7.00%, Co≤2.50%, V≤0.35%, with the balance being Ni and unavoidable impurities.

[0008] Furthermore, when the compression ratio is ≤3, the first stage insulation temperature is 1200℃.

[0009] Furthermore, when the compression ratio is between 3 and 6, the first stage of heat preservation time is 2 minutes.

[0010] Furthermore, when the compression ratio is ≥6, the holding temperature after the cooling step is 1190℃.

[0011] Furthermore, heat treatment methods to improve the corrosion resistance of high-molybdenum tungsten nickel-based alloy plates also include preparing billets by continuous casting before rolling and homogenizing the continuously cast billets.

[0012] Furthermore, after heat treatment, the grain size of the plate is grade 3-4.

[0013] Furthermore, after heat treatment, the corrosion resistance of the plate meets the following requirements: corrosion rate ≤ 3.95 mm / a for ASTM G28 A method and corrosion rate ≤ 1.12 mm / a for ASTM G28 B method.

[0014] Furthermore, after heat treatment, the mechanical properties of the sheet material meet the following requirements: yield strength ≥ 311 MPa, tensile strength ≥ 757 MPa, and elongation ≥ 68%.

[0015] Furthermore, the high-molybdenum tungsten nickel-based alloy is the N10276 alloy.

[0016] Compared with existing technologies that use single-temperature long-term solution treatment (e.g., holding at 1200℃ for 40 min) leading to grain coarsening to grade 0-2, or directly lowering the temperature (e.g., holding at 1180℃) leading to precipitate residue and significantly deteriorated corrosion performance (the corrosion rate of ASTM G28 A method is as high as 7.45-11.38 mm / a), the heat treatment method of the present invention for improving the corrosion performance of high-molybdenum tungsten nickel-based alloy medium plates solves the contradiction between precipitate remelting and grain refinement in the heat treatment of high-molybdenum tungsten nickel-based alloy medium plates by dynamically coupling the heat treatment process with the rolling compression ratio and adopting a segmented heat treatment strategy of high-temperature short-time remelting and medium-temperature controlled recrystallization. This method allows for the complete redissolution of high-melting-point precipitates such as WC and MoC, reducing the corrosion rate by over 60% (down to 3.07 mm / a using the ASTM G28A method). Simultaneously, it precisely controls the grain size to grade 3-4, avoiding the mechanical property degradation caused by grain coarsening, and achieves an excellent strength-ductility balance of yield strength ≥311 MPa, tensile strength ≥757 MPa, and elongation ≥68%. This heat treatment method for improving the corrosion resistance of high-molybdenum tungsten nickel-based alloy plates not only significantly enhances the overall corrosion resistance and mechanical properties of the product, but also improves the process adaptability and stability through compression ratio correlation. This provides a guarantee for the long-life, high-reliability application of high-molybdenum tungsten nickel-based alloys in harsh environments such as petrochemicals, marine engineering, and national defense. Attached Figure Description

[0017] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the embodiments of this application. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 A flowchart of a heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to the present invention is shown. Detailed Implementation

[0018] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

[0019] Figure 1 A heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to an embodiment of the present invention is shown. For example... Figure 1 As shown, the method may include the following steps: Designing and implementing a heat treatment process based on the rolling compression ratio of the finished plate: When the compression ratio is ≤3, the first segment of the heat treatment curve has a holding temperature of 1200-1210℃ for 3 minutes, followed by cooling to 1180-1200℃ for 2 minutes per mm of plate thickness, and then water cooling; when the compression ratio is between 3 and 6, the first segment of the heat treatment curve has a holding temperature of 1210-1230℃ for 2-3 minutes, followed by cooling to 1180-1200℃ for 2 minutes per mm of plate thickness, and then water cooling; when the compression ratio is ≥6, the first segment of the heat treatment curve has a holding temperature of 1220-1230℃ for 2 minutes, followed by cooling to 1180-1200℃ for 2 minutes per mm of plate thickness, and then water cooling. The rolling compression ratio of the finished plate is determined based on the ratio of the finished plate thickness to the billet thickness.

[0020] When using the heat treatment method for improving the corrosion resistance of high-molybdenum tungsten nickel-based alloy plates according to embodiments of the present invention, firstly, the rolling compression ratio (the ratio of the finished plate thickness to the billet thickness) of the high-molybdenum tungsten nickel-based alloy plate to be treated is determined. Then, the corresponding heat treatment regime is selected according to the range of the compression ratio. By directly linking the heat treatment process regime with the rolling compression ratio of the finished plate, differentiated treatment of plates with different deformation histories is achieved. The first stage of holding at a high temperature (1200-1230℃) ensures rapid re-dissolution of high-melting-point precipitates such as WC and MoC; the second stage of cooling followed by holding at a high temperature (1180-1200℃) inhibits abnormal grain growth and promotes uniform recrystallization. This method simultaneously resolves the contradiction between residual precipitates damaging corrosion resistance and grain coarsening reducing mechanical properties, significantly improving the overall performance of the plate.

[0021] The core advantage of the heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates in this invention lies in dynamic matching and segmented control. Dynamic matching refers to the variation of heat treatment parameters with the compression ratio, ensuring that the plates under different deformation and energy storage conditions can obtain the optimal heat treatment response. Segmented control refers to using a first stage of high temperature for a short time to achieve rapid dissolution of precipitates, and using a second stage of medium temperature holding to achieve controllable grain growth. Compared with traditional single-temperature long-time solution treatment, the heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates in this invention effectively solves the inherent contradiction between the need for high temperature for precipitate dissolution and the need to avoid high temperature for long time for grain refinement in high-molybdenum tungsten-nickel-based alloys. This significantly reduces the corrosion rate of the plates, refines the grain size, and achieves or even improves the overall mechanical properties, resulting in a substantial improvement in comprehensive performance.

[0022] According to the present invention, the composition of the high-molybdenum tungsten nickel-based alloy, by weight percentage, may include: C≤0.010%, Si≤0.08%, Mn≤1.00%, P≤0.040%, S≤0.030%, Cr 14.50-16.50%, Mo 15.00-17.00%, W 3.00-4.50%, Fe 4.00-7.00%, Co≤2.50%, V≤0.35%, with the balance being Ni and unavoidable impurities. In this composition system, the Mo and W contents are extremely high, making the redissolution of precipitates difficult. The heat treatment method for improving the corrosion resistance of the high-molybdenum tungsten nickel-based alloy plate according to the embodiments of the present invention is specifically designed for this system, ensuring the feasibility and repeatability of the method.

[0023] Preferably, the high-molybdenum tungsten nickel-based alloy can be N10276 alloy.

[0024] In a preferred embodiment, when the compression ratio is ≤3, the first stage holding temperature is 1200℃. This preferred value can minimize the heat treatment temperature while ensuring sufficient re-dissolution of precipitates, thereby reducing energy consumption and the risk of grain coarsening, and enabling the low compression ratio plate to obtain a more stable fine-grained structure.

[0025] Furthermore, when the compression ratio is between 3 and 6, the first holding time is 2 minutes. This minimum holding time ensures rapid re-dissolution of precipitates at high temperatures while maximally limiting the growth time of grains at extreme high temperatures, thus achieving the best balance between precipitate re-dissolution and grain refinement in medium compression ratio plates.

[0026] Furthermore, when the compression ratio is ≥6, the holding temperature after the cooling step is 1190℃. This temperature is in the middle to high range of 1180-1200℃, which is conducive to the full release of the high deformation energy stored in the high compression ratio plate, making the recrystallized structure more uniform, while avoiding excessive grain growth and obtaining fine recrystallized grains.

[0027] According to the present invention, the heat treatment method for improving the corrosion resistance of high-molybdenum tungsten nickel-based alloy plates may further include preparing a billet by continuous casting before rolling, and performing homogenization treatment on the continuously cast billet. Continuous casting can reduce the segregation of Mo and W elements, and homogenization treatment further eliminates the compositional inhomogeneity inside the ingot, providing a billet with a uniform microstructure for subsequent rolling and heat treatment, fundamentally improving the consistency and stability of the final plate properties.

[0028] Furthermore, after heat treatment, the grain size grade of the plate is 3-4. This grain size index reflects the precise control of grain size by the heat treatment method of the present invention for improving the corrosion resistance of high molybdenum tungsten nickel-based alloy plates. It avoids the defect of grain coarsening to grade 0 or even grade 00 caused by single-temperature heat treatment in the prior art, and ensures that the material has excellent strength-plasticity matching.

[0029] Furthermore, after heat treatment, the corrosion resistance of the plate meets the following requirements: corrosion rate ≤ 3.95 mm / a for ASTM G28 A method and corrosion rate ≤ 1.12 mm / a for ASTM G28 B method. These quantitative indicators directly demonstrate the significant improvement in corrosion resistance achieved by the heat treatment method of this invention, which enhances the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates. Compared to single-temperature heat treatment or direct low-temperature treatment in existing technologies, the corrosion rate is reduced by approximately 60% or more, resulting in a substantial improvement in the product's corrosion resistance.

[0030] Furthermore, after heat treatment, the mechanical properties of the plate meet the following requirements: yield strength ≥ 311 MPa, tensile strength ≥ 757 MPa, and elongation ≥ 68%. These indicators demonstrate that the heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates in this embodiment of the invention does not sacrifice mechanical properties while improving corrosion resistance; on the contrary, it results in yield strength and elongation that are superior to conventional processes, achieving a synergistic improvement in corrosion resistance, strength, and plasticity.

[0031] The following are specific embodiments of the heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy medium plates according to the present invention: Example 1 This embodiment provides a heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates, specifically including the following steps: (1) Billet preparation: N10276 alloy slabs were prepared by continuous casting process, and their actual chemical composition is shown in Table 1 below. The continuous casting billets were homogenized to reduce the segregation of Mo and W elements.

[0032] (2) Finished product rolling: The homogenized slab is hot rolled to obtain finished medium plate with a specification of 20mm×2000mm×6000mm. The rolling compression ratio is 2.8 (≤3).

[0033] (3) Heat treatment process: According to the compression ratio ≤3, the following heat treatment system shall be implemented: the first stage heat treatment temperature is 1200℃ and the heat treatment time is 3min; then the temperature is reduced to 1180℃ and the heat treatment time is calculated according to the plate thickness 2min / mm, that is, 20mm×2min / mm=40min; then the temperature is cooled to room temperature by water.

[0034] (4) Performance test: The finished plate after heat treatment was subjected to comprehensive performance test. The results are as follows: Mechanical properties: yield strength 311MPa, tensile strength 770MPa, elongation 69%; grain size: grade 4; corrosion resistance: corrosion rate of ASTM G28 A method 3.48mm / a, corrosion rate of ASTM G28 B method 1.07mm / a.

[0035] Table 1

[0036] Comparative Example 1-1 The same sheet material as in Example 1 was used, but the material was kept at a single temperature of 1200℃ for 40 minutes and then water-cooled. The test results were: yield strength 285MPa, tensile strength 671MPa, elongation 67%, grain size grade 2, corrosion rate of 3.52mm / a under ASTM G28 A method, and corrosion rate of 1.05mm / a under ASTM G28 B method.

[0037] Comparative Examples 1-2 The same sheet material as in Example 1 was used, but the material was kept at a single temperature of 1180℃ for 40 minutes and then water-cooled. The test results were: yield strength 325MPa, tensile strength 769MPa, elongation 62%, grain size grade 4, corrosion rate of 7.45mm / a under ASTM G28 A method, and corrosion rate of 2.18mm / a under ASTM G28 B method.

[0038] As can be seen from the comparison, the corrosion performance of Example 1 is far superior to that of Comparative Examples 1-2, and its mechanical properties are superior to those of Comparative Example 1-1, achieving a good match between corrosion and mechanical properties.

[0039] Example 2 This embodiment provides another heat treatment method to improve the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates. The specific steps are as follows: (1) Billet preparation: The same continuous casting billet and composition as in Example 1 (same as Table 1) were used.

[0040] (2) Finished product rolling: hot rolling to obtain finished medium plate with specifications of 16mm×2500mm×8000mm. The rolling compression ratio is 2.5 (≤3).

[0041] (3) Heat treatment process: According to the compression ratio ≤3, the following heat treatment system shall be implemented: First stage heat treatment temperature: 1200℃, heat treatment time: 3min; then cool down to 1180℃, heat treatment time is calculated according to the plate thickness 2min / mm, that is, 16mm×2min / mm=32min; then water cooling.

[0042] (4) Performance test: Test results: Mechanical properties: Yield strength 327MPa, tensile strength 781MPa, elongation 68%; Grain size: Grade 4; Corrosion resistance: ASTM G28 A corrosion rate 3.95mm / a, ASTM G28 B corrosion rate 1.12mm / a.

[0043] Comparative Example 2-1 Using the same sheet material, the material was held at 1200℃ for 32 minutes and then water-cooled. Test results: Yield strength 301MPa, tensile strength 685MPa, elongation 62%, grain size 2.5, corrosion rate 4.17mm / a for ASTM G28 A method, and corrosion rate 1.15mm / a for ASTM G28 B method.

[0044] Comparative Example 2-2 Using the same sheet material, the material was held at 1180℃ for 32 minutes and then water-cooled. Test results: Yield strength 331MPa, tensile strength 780MPa, elongation 57%, grain size grade 4, corrosion rate 8.45mm / a under ASTM G28 A method, and corrosion rate 2.35mm / a under ASTM G28 B method.

[0045] The corrosion performance of Example 2 is improved by more than 50% compared with Comparative Example 2-2, and its mechanical properties are better than those of Comparative Example 2-1.

[0046] Example 3 This embodiment provides another heat treatment method to improve the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates. The specific steps are as follows: (1) Billet preparation: The same continuous casting billet and composition as in Example 1 were used.

[0047] (2) Finished product rolling: hot rolling to obtain finished medium plate with specifications of 12mm×2000mm×8000mm. The rolling compression ratio is 5 (between 3 and 6).

[0048] (3) Heat treatment process: According to the compression ratio of 3-6, the following heat treatment system shall be implemented: First stage heat treatment temperature: 1220℃, heat treatment time: 2min; then cool down to 1180℃, heat treatment time is calculated according to the plate thickness 2min / mm, that is, 12mm×2min / mm=24min; then water cooling.

[0049] (4) Performance test: Test results: Mechanical properties: Yield strength 318MPa, tensile strength 757MPa, elongation 71%; Grain size: 3-4 grade; Corrosion resistance: ASTM G28 A method corrosion rate 3.13mm / a, ASTM G28 B method corrosion rate 1.01mm / a.

[0050] Comparative Example 3-1 Using the same sheet material, the material was kept at 1220℃ for 24 minutes and then water-cooled. Test results: Yield strength 274MPa, tensile strength 669MPa, elongation 57%, grain size grade 0, corrosion rate 4.49mm / a under ASTM G28 A method, and corrosion rate 1.75mm / a under ASTM G28 B method.

[0051] Comparative Example 3-2 Using the same sheet material, the material was kept at 1180℃ for 24 minutes and then water-cooled. Test results: Yield strength 341MPa, tensile strength 797MPa, elongation 52%, grain size grade 5, corrosion rate 9.01mm / a under ASTM G28 A method, and corrosion rate 2.79mm / a under ASTM G28 B method.

[0052] The corrosion performance of Example 3 is far superior to that of Comparative Example 3-2, and its grain size and mechanical properties are significantly better than those of Comparative Example 3-1.

[0053] Example 4 This embodiment provides another heat treatment method to improve the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates. The specific steps are as follows: (1) Billet preparation: The same continuous casting billet and composition as in Example 1 were used.

[0054] (2) Finished product rolling: hot rolling to obtain finished medium plate with specifications of 8mm×2100mm×6000mm. The rolling compression ratio is 9 (≥6).

[0055] (3) Heat treatment process: According to the compression ratio ≥6, the following heat treatment system shall be implemented: First stage heat treatment temperature: 1230℃, heat treatment time: 2min; then cool down to 1190℃, heat treatment time is calculated according to the plate thickness 2min / mm, that is, 8mm×2min / mm=16min; then water cooling.

[0056] (4) Performance test: Test results: Mechanical properties: Yield strength 334MPa, tensile strength 781MPa, elongation 68%; Grain size: Grade 4; Corrosion resistance: ASTM G28 A corrosion rate 3.07mm / a, ASTM G28 B corrosion rate 1.12mm / a.

[0057] Comparative Example 4-1 Using the same sheet material, the material was kept at 1230℃ for 16 minutes and then water-cooled. Test results: Yield strength 251MPa, tensile strength 661MPa, elongation 47%, grain size grade 00, corrosion rate 8.08mm / a under ASTM G28 A method, and corrosion rate 1.67mm / a under ASTM G28 B method.

[0058] Comparative Example 4-2 Using the same sheet material, the material was held at 1190℃ for 16 minutes and then water-cooled. Test results: Yield strength 379MPa, tensile strength 834MPa, elongation 61%, grain size 5-6, corrosion rate 11.38mm / a for ASTM G28 A method, and corrosion rate 3.75mm / a for ASTM G28 B method.

[0059] The corrosion performance of Example 4 is improved by about 70% compared with Comparative Example 4-2, and its mechanical properties are far superior to those of Comparative Example 4-1.

[0060] The four embodiments above correspond to three operating conditions: compression ratio ≤3, 3-6, and ≥6, respectively. All four embodiments achieved excellent corrosion resistance and mechanical properties through the segmented heat treatment method of the high-molybdenum tungsten-nickel-based alloy medium plate of this invention. Compared with the comparative examples, the heat treatment method of the high-molybdenum tungsten-nickel-based alloy medium plate of this invention effectively controls the grain size while ensuring sufficient dissolution of precipitates, thus achieving a significant improvement in the overall performance of the high-molybdenum tungsten-nickel-based alloy medium plate.

[0061] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered within the scope of the claims and specification of the present invention. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. The present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates, characterized in that, Includes the following steps: The heat treatment process is designed and implemented based on the rolling compression ratio of the finished plate. When the compression ratio is ≤3, the first section of the heat treatment curve is held at 1200-1210℃ for 3 minutes, then cooled to 1180-1200℃ for 2 minutes per mm of plate thickness, followed by water cooling. When the compression ratio is between 3 and 6, the first section of the heat treatment curve should be held at 1210-1230℃ for 2-3 minutes, then cooled to 1180-1200℃ for 2 minutes per mm of plate thickness, followed by water cooling. When the compression ratio is ≥6, the first segment of the heat treatment curve should be held at 1220-1230℃ for 2 minutes, then cooled to 1180-1200℃ for 2 minutes per mm of plate thickness, followed by water cooling. The finished plate rolling compression ratio is determined based on the ratio of the finished plate thickness to the billet thickness.

2. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, The composition of the high-molybdenum tungsten nickel-based alloy, by weight percentage, includes: C≤0.010%, Si≤0.08%, Mn≤1.00%, P≤0.040%, S≤0.030%, Cr 14.50-16.50%, Mo 15.00-17.00%, W 3.00-4.50%, Fe 4.00-7.00%, Co≤2.50%, V≤0.35%, with the balance being Ni and unavoidable impurities.

3. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, When the compression ratio is ≤3, the first stage insulation temperature is 1200℃.

4. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, When the compression ratio is between 3 and 6, the first stage of heat preservation time is 2 minutes.

5. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, When the compression ratio is ≥6, the holding temperature after the cooling step is 1190℃.

6. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten nickel-based alloy plates also includes preparing billets by continuous casting before rolling and homogenizing the continuously cast billets.

7. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, After the heat treatment process described above, the grain size grade of the plate is 3-4.

8. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, After the heat treatment process described above, the corrosion resistance of the plate meets the following requirements: corrosion rate ≤ 3.95 mm / a for ASTM G28 A method and corrosion rate ≤ 1.12 mm / a for ASTM G28 B method.

9. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, After the heat treatment process, the mechanical properties of the sheet material meet the following requirements: yield strength ≥ 311 MPa, tensile strength ≥ 757 MPa, and elongation ≥ 68%.

10. The heat treatment method for improving the corrosion resistance of high-molybdenum tungsten-nickel-based alloy plates according to claim 1, characterized in that, The high-molybdenum tungsten-nickel-based alloy is N10276 alloy.

Images