A high width-thickness ratio plate hot rolling and heat treatment process of a difficult-to-deform alloy
By optimizing the composition and using a multi-stage temperature-controlled rolling process, the problems of cracking, uneven microstructure, and performance fluctuations in GH4099 alloy medium-thick plates during the rolling process were solved, and stable production of high-temperature components was achieved.
Patent Information
- Application Number
- CN202610649944.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-12
- Publication Date
- 2026-08-25
AI Technical Summary
The rolling process of GH4099 alloy medium and thick plates presents problems such as high risk of rolling cracks, difficulty in controlling temperature and deformation, uneven microstructure and large performance fluctuations, which leads to difficulties in the production of high-temperature components for aero engines.
The process employs composition optimization, multi-stage temperature-controlled rolling, and precise deformation control, including billet heating, hot rolling, and heat treatment. By setting appropriate heating temperatures and deformation amounts, combined with surface quality inspection and grinding, the uniform microstructure and stable performance of the sheet metal are ensured.
High-quality rolling of GH4099 alloy medium-thick plates has been achieved, ensuring the stability of plate surface quality and mechanical properties, and meeting the requirements for use in high-temperature components of aero-engines.
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Figure CN122629282A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of alloy material preparation technology, specifically relating to a hot rolling and heat treatment process for a high aspect ratio plate of a difficult-to-deform alloy. Background Technology
[0002] GH4099 alloy has a Ni and Cr matrix, with Al, Ti, W, Co, Mo, B, and Mg as strengthening elements. This alloy is a highly alloyed, difficult-to-deform, age-hardening nickel-based superalloy. Due to its excellent comprehensive properties, it can operate at temperatures up to approximately 1000℃ and is widely used in high-temperature plate welded structural components, stiffeners, baffles, and blades in aero-engines, such as combustion chambers and afterburners. With the continuous development and upgrading of aero-engines, the quality requirements for large plate structural components made of GH4099 are becoming increasingly stringent.
[0003] GH4099 alloy possesses high thermal strength, capable of long-term stable operation at 900℃ and even withstanding short-term temperatures up to 1000℃. However, this alloy faces a series of common industry-wide technical challenges during rolling: First, its high deformation resistance leads to a high risk of rolling cracking. Due to the high content of elements such as Al and Ti in the alloy, the γ' phase has a significant strengthening effect, making the alloy's deformation resistance during rolling 2-3 times that of ordinary alloys. This easily leads to the formation of crack initiation points at grain boundaries, resulting in a rolling cracking rate as high as 15%-20%. Second, the alloy is extremely sensitive to processing temperature and deformation amount. Rolling temperature deviations exceeding ±20℃ or improper deformation control can easily lead to microstructural defects such as grain coarsening and mixed grains. Experimental data shows that when the solution temperature exceeds 1100℃, the grain size significantly increases from ASTM grade 5 to grade 7, while the γ' phase at grain boundaries... 23 The C6 carbides are distributed in a chain-like pattern, which seriously affects the alloy's 900℃ creep strength and fatigue resistance. Finally, the existing process parameter window is narrow and unstable, making it difficult to ensure the consistency of performance between batches. This results in the final product performance fluctuating by as much as 10%-15%, which cannot meet the stringent requirements of aero-engines for key components.
[0004] Currently, the rolling process for GH4099 alloy mainly focuses on cold-rolled thin plates (δ≤5mm) and hot-rolled bars. However, for the rolling process of medium-thick plates (20-70mm thick) required for large structural components of aero-engines, the industry has long faced two major technical bottlenecks: First, the challenge of precisely controlling temperature and deformation during the rolling process. Due to the complex alloy composition and low thermal conductivity (approximately 10.5 W / (m·K)), it is difficult to achieve uniform deformation and microstructure control throughout the entire thickness direction. Second, the challenge of ensuring dimensional stability and surface quality of the plate. Traditional rolling processes easily lead to uneven plate thickness, surface scratches, and internal defects, affecting the reliability and service life of the final product in high-temperature environments. Regrettably, despite extensive research by domestic and international research institutions and enterprises, as of the date of this application, no systematic technical solutions for the rolling process of medium-thick plates of GH4099 alloy have been publicly reported. This technological gap severely restricts the independent production of key high-temperature components for aero-engines in China.
[0005] This invention addresses the aforementioned technical challenges by providing an innovative process for rolling medium-thick plates of GH4099 nickel-based high-temperature alloy. Through key technologies such as composition optimization, multi-stage temperature-controlled rolling, and precise control of rolling deformation, this process effectively solves problems such as cracking, uneven microstructure, and performance fluctuations during the rolling of GH4099 alloy medium-thick plates, providing reliable technical support for the domestic production of high-temperature components for aero-engines. Summary of the Invention
[0006] The purpose of this invention is to provide a hot rolling and heat treatment process for high aspect ratio alloy plates that are difficult to deform. By adjusting the heating temperature, deformation amount, and multiple rolling processes, the required performance indicators can be achieved, and the plate can have a good surface quality.
[0007] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:
[0008] A hot rolling and heat treatment process for high aspect ratio alloy plates that are difficult to deform, comprising forging billet heating, hot rolling, and heat treatment; the specific process is as follows:
[0009] 1) Heating of forging billets: The heating temperature of both forging billets and intermediate billets is 1120~1160℃, and the holding time is 1.5~2h;
[0010] 2) Hot rolling:
[0011] Plates with a finished thickness h of 70mm≤h≤90mm are rolled in one pass, that is, after the billet exits the furnace, it is rolled with a single pass reduction of 0.5 to 7mm until the required size is reached;
[0012] Plates with a finished thickness h of 40mm≤h<70mm are rolled in two passes. The first pass should allow for 35% to 50% of the deformation for the final pass.
[0013] For plates with a finished thickness h of 20mm≤h<39mm, three-stage rolling is required. The deformation of the final rolling stage must be 35%~50%. The first two rolling stages can be evenly or appropriately distributed according to the actual site conditions.
[0014] 3) Heat treatment: The finished board is solution treated at 1050-1100℃ for 1-2 min / mm, air cooled, and then aged at 800℃ for 8-10 h.
[0015] The chemical composition and mass percentage of the difficult-to-deform alloy described in this invention are as follows: C≤0.08%, Cr: 17.00~20.00%, W: 5.00~7.00%, Mo: 3.50~4.50%, Ti: 1.10~1.50%, Al: 1.70~2.30%, Co: 5.00~8.00%, Fe≤2.00%, with the balance being Ni and other unavoidable impurities.
[0016] The thickness of the difficult-to-deform alloy described in this invention is 20-70 mm.
[0017] The hot rolling process described in this invention includes grinding. After each rolling cycle, the slab is air-cooled and then the surface quality is checked. If there are cracks, grinding is required, with a grinding amount of 0.1 to 1 mm.
[0018] The forging blank of the present invention has a size of 130-160mm, a width of ≥800mm, and a length of 1990-2220mm.
[0019] The mechanical properties of the difficult-to-deform alloy described in this invention after heat treatment are as follows: room temperature properties: tensile strength ≥1080MPa, yield strength ≥650MPa, elongation after fracture ≥20%, reduction of area ≥32%.
[0020] The mechanical properties of the difficult-to-deform alloy described in this invention after heat treatment are as follows: 900℃ properties: tensile strength ≥400MPa, elongation after fracture ≥15%, reduction of area ≥30%.
[0021] The mechanical properties of the difficult-to-deform alloy described in this invention after heat treatment are: 900℃, 98MPa, creep rupture: not less than 24h.
[0022] The beneficial effects of adopting the above technical solution are as follows: 1. This invention sets the heating temperature of the forging billet and intermediate billet to 1120~1160℃, lower than the forging heating temperature, in order to achieve low-temperature rolling, avoid excessive grain growth caused by high heating temperature, and refine the grains in conjunction with large deformation, thereby ensuring the mechanical properties. 2. This invention determines the rolling passes according to different finished plate thicknesses, rationally allocates the deformation amount, and inspects the surface of the intermediate billet. If cracks are found, they are ground to eliminate crack sources for subsequent rolling passes, ensuring the surface quality of the finished plate and preventing crack propagation during the rolling process. 3. The solution treatment time of this invention is calculated at 1~2 min / mm based on the thickness of the finished plate. Different solution treatment times are used for different specifications of plates, thereby ensuring the quality stability of plates of various specifications. Attached Figure Description
[0023] Figure 1 The metallographic structure of the GH4099 alloy in Example 1 is shown below.
[0024] Figure 2 Metallographic diagram of GH4099 alloy in Example 2;
[0025] Figure 3 The metallographic structure of the GH4099 alloy in Example 3 is shown below.
[0026] Figure 4 The image shows the metallographic structure of the GH4099 alloy in Example 4. Detailed Implementation
[0027] The present invention will now be described in further detail with reference to specific embodiments.
[0028] Example 1
[0029] A hot rolling and heat treatment process for high aspect ratio GH4099 alloy plates that are difficult to deform, comprising forging billet heating, hot rolling, and heat treatment; the specific process for rolling GH4099 alloy plates of 90mm*1000mm*1000mm is as follows:
[0030] (1) Heating of forging billet: Use a forging billet of 160mm*821mm*2220mm, heat it to 1120℃ in the furnace, and hold it for 1.5h;
[0031] (2) Hot rolling: The billet is rolled in one pass after it is taken out of the furnace. The billet is rolled with a single pass reduction of 0.5~7mm until the thickness is 90mm. If there are cracks, they need to be repaired by grinding, with a grinding amount of 0.1~1mm.
[0032] (3) Heat treatment: The finished board is solution treated at 1100℃, the heat treatment time is 1min / mm, water cooled, and then aged at 800℃ for 10h.
[0033] After heat treatment, a sample was taken from the end of the plate, and the metallographic structure was as follows. Figure 1 As shown in Table 1, the chemical composition and its mass percentage are presented. The microstructure after solution treatment and aging is fine and uniform, with a uniform distribution of carbides. Its mechanical properties meet the standards, as follows:
[0034]
[0035] Example 2
[0036] A hot rolling and heat treatment process for high aspect ratio alloy plates that are difficult to deform, comprising forging billet heating, hot rolling, and heat treatment; and rolling GH4099 alloy plates of 70mm*1000mm*2000mm, the specific process is as follows:
[0037] (1) Heating of forging billet: Use a forging billet of 130mm*814mm*1990mm, heat it to 1160℃ in the furnace, and hold it for 1.5h;
[0038] (2) Hot rolling: The billet is rolled in one pass after it is taken out of the furnace. The billet is rolled with a single pass reduction of 0.5~7mm until the thickness is 70mm. If there are cracks, they need to be repaired by grinding, with a grinding amount of 0.1~1mm.
[0039] (3) Heat treatment: The finished board is solution treated at 1050℃ for 2 min / mm, then water cooled, and then aged at 800℃ for 8 h.
[0040] After heat treatment, a sample was taken from the end of the plate, and the metallographic structure was as follows. Figure 2 As shown in Table 1, the chemical composition and its mass percentage are presented. The microstructure after solution treatment and aging is fine and uniform, with a uniform distribution of carbides. Its mechanical properties meet the standards, as follows:
[0041]
[0042] Example 3
[0043] A hot rolling and heat treatment process for high aspect ratio alloy plates that are difficult to deform, comprising forging billet heating, hot rolling, and heat treatment; and rolling GH4099 alloy plates of 50mm*1000mm*2000mm, the specific process is as follows:
[0044] (1) Heating of forging billet: Use a forging billet of 148mm*815mm*2080mm, heat it to 1150℃ in the furnace and hold it for 2 hours;
[0045] (2) Hot rolling: The billet is rolled in two passes. After exiting the furnace, it is rolled with a single pass reduction of 0.5~7mm until it reaches a thickness of 90mm. After cooling, the surface of the intermediate billet is inspected. If there are cracks, they need to be ground. The grinding amount is 0.1~1mm. After grinding, it is loaded into the furnace and heated to 1120℃ and held for 1.5h. It is then rolled with a single pass reduction of 0.5~7mm until it reaches a thickness of 50mm.
[0046] (3) Heat treatment: The finished board is solution treated at 1070℃ for 1.5 min / mm, water cooled, and then aged at 800℃ for 9 h.
[0047] After heat treatment, a sample was taken from the end of the plate, and the metallographic structure was as follows. Figure 3 As shown in Table 1, the chemical composition and its mass percentage are presented. The microstructure after solution treatment and aging is fine and uniform, with a uniform distribution of carbides. Its mechanical properties meet the standards, as follows:
[0048]
[0049] Example 4
[0050] A hot rolling and heat treatment process for high aspect ratio alloy plates that are difficult to deform, comprising forging billet heating, hot rolling, and heat treatment; and rolling GH4099 alloy plates of 20mm*1000mm*2000mm, the specific process is as follows:
[0051] (1) Heating of forging billet: Use a forging billet of 148mm*818mm*2090mm, heat it to 1140℃ in the furnace, and hold it for 1.8h;
[0052] (2) Hot rolling: The billet is formed by two passes. After exiting the furnace, it is rolled with a single pass reduction of 0.5~7mm until it reaches a thickness of 80mm. It is then air-cooled. After cooling, the surface of the intermediate billet is inspected. If there are cracks, they need to be ground. After grinding, it is loaded into the furnace and heated to 1120℃ and held for 1.5h. It is then rolled with a single pass reduction of 0.5~7mm until it reaches a thickness of 45mm. After cooling, the surface of the intermediate billet is inspected. If there are cracks, they need to be ground. The grinding amount is 0.1~1mm. After grinding, it is loaded into the furnace and heated to 1120℃ and held for 1.5h. It is then rolled with a single pass reduction of 0.5~7mm until it reaches a thickness of 20mm.
[0053] (3) Heat treatment: The finished board is solution treated at 1050℃ for 1.2 min / mm, water cooled, and then aged at 800℃ for 9.5 h.
[0054] After heat treatment, a sample was taken from the end of the plate, and the metallographic structure was as follows. Figure 4As shown in Table 1, the chemical composition and its mass percentage are presented. The microstructure after solution treatment and aging is fine and uniform, with a uniform distribution of carbides. Its mechanical properties meet the standards, as follows:
[0055]
[0056] Table 1 Chemical composition and mass percentage of alloy steels in Examples 1-4
[0057]
[0058] The above embodiments are only used to illustrate and not limit the technical solutions of the present invention. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the present invention without departing from the spirit and scope of the present invention. Any modifications or partial substitutions should be covered within the scope of the claims of the present invention.
Claims
1. A hot rolling and heat treatment process for high aspect ratio steel plates made of difficult-to-deform alloys, characterized in that, The process involves heating the forging billet, hot rolling, and heat treatment; the specific process is as follows: 1) Heating of forging billets: The heating temperature of both forging billets and intermediate billets is 1120~1160℃, and the holding time is 1.5~2h; 2) Hot rolling: Plates with a finished thickness h of 70mm≤h≤90mm are rolled in one pass, that is, after the billet exits the furnace, it is rolled with a single pass reduction of 0.5 to 7mm until the required size is reached; Plates with a finished thickness h of 40mm≤h<70mm are rolled in two passes. The first pass should allow for 35% to 50% of the deformation for the final pass. For plates with a finished thickness h of 20mm≤h<39mm, three-stage rolling is required. The deformation of the final rolling stage must be 35%~50%. The first two rolling stages can be evenly or appropriately distributed according to the actual site conditions. 3) Heat treatment: The finished board is solution treated at 1050-1100℃ for 1-2 min / mm, then water cooled, and finally aged at 800℃ for 8-10 h.
2. The hot rolling and heat treatment process for a difficult-to-deform alloy high aspect ratio plate according to claim 1, characterized in that, The chemical composition and mass percentage of the difficult-to-deform alloy are as follows: C≤0.08%, Cr: 17.00~20.00%, W: 5.00~7.00%, Mo: 3.50~4.50%, Ti: 1.10~1.50%, Al: 1.70~2.30%, Co: 5.00~8.00%, Fe≤2.00%, with the balance being Ni and other unavoidable impurities.
3. The hot rolling and heat treatment process for a difficult-to-deform alloy high aspect ratio plate according to claim 1, characterized in that, The thickness of the difficult-to-deform alloy is 20-70 mm.
4. The hot rolling and heat treatment process for a difficult-to-deform alloy high aspect ratio plate according to claim 1, characterized in that, The hot rolling process includes grinding. After each rolling cycle, the slab is air-cooled and then the surface quality is checked. If there are cracks, grinding is required, with a grinding amount of 0.1 to 1 mm.
5. The hot rolling and heat treatment process for a difficult-to-deform alloy high aspect ratio plate according to any one of claims 1-4, characterized in that, The forging billet has dimensions of 130–160 mm, a width of ≥800 mm, and a length of 1990–2220 mm.
6. The hot rolling and heat treatment process for a difficult-to-deform alloy high aspect ratio plate according to any one of claims 1-4, characterized in that, The mechanical properties of the difficult-to-deform alloy after heat treatment are as follows: room temperature properties: tensile strength ≥1080MPa, yield strength ≥650MPa, elongation after fracture ≥20%, reduction of area ≥32%.
7. The hot rolling and heat treatment process for a difficult-to-deform alloy high aspect ratio plate according to any one of claims 1-4, characterized in that, The mechanical properties of the difficult-to-deform alloy after heat treatment are as follows: 900℃ properties: tensile strength ≥400MPa, elongation after fracture ≥15%, reduction of area ≥30%.
8. The hot rolling and heat treatment process for a difficult-to-deform alloy high aspect ratio plate according to any one of claims 1-4, characterized in that, The mechanical properties of the difficult-to-deform alloy after heat treatment are: 900℃, 98MPa, creep rupture: not less than 24h.