A large-size titanium-based composite sheet resistant to 750℃ and its cladding and rolling method

Abstract

This invention discloses a method for rolling a large-size titanium-based composite material sheet resistant to 750℃ and its cladding. The method involves obtaining a large-size titanium-based composite material ingot through vacuum arc melting, followed by annealing and machining to obtain a forging billet. Multi-directional forging technology is used for forging, and the forged billet is annealed and machined to obtain a rolled billet of the required specifications. By rationally designing the ratio of billet thickness to cladding material thickness and hot rolling process parameters, including deformation per pass, rolling temperature, and rolling rate, a high-quality large-size titanium-based composite material sheet is finally obtained. The method provided by this invention is simple and stable, and can well meet the requirements of industrial production. Simultaneously, it effectively improves the matching between the billet and cladding materials, avoiding problems such as sheet deformation and cracking. Furthermore, the cladding rolling effectively suppresses hydrogen and oxygen absorption and promotes rapid heat dissipation, ensuring that the mechanical properties of the sheet remain at a high level.

Description

Technical Field

[0001] This invention belongs to the field of high-temperature titanium-based composite material sheet manufacturing, and specifically relates to a large-size titanium-based composite material thin sheet resistant to 750℃ and its cladding and rolling method. Background Technology

[0002] The development of sheet metal fabrication processes has driven the progress of the titanium alloy industry. In 2004, the global economic recovery further propelled the development of the titanium alloy industry, with demand for titanium alloy sheets, especially high-performance thin sheets and high-precision wide sheets, continuing to grow. In 2020, with the completion of structural adjustments and transformation and upgrading in my country's titanium processing industry, the demand for titanium alloy sheets in mid-to-high-end fields such as aerospace, marine engineering, and shipbuilding significantly increased. However, in recent years, the service environment in the aerospace field has become increasingly demanding, especially the construction of integrated aerospace equipment, which places higher requirements on materials used in high Mach number aircraft. This has significantly limited the service life of traditional titanium alloy sheets. The emergence of titanium-based composite materials, characterized by low density, high specific strength, high specific modulus, excellent high-temperature mechanical properties, and corrosion resistance, provides a new approach to overcoming these service barriers.

[0003] Although titanium-based composites have excellent high-temperature service performance, their hot deformation capacity is significantly low, making the preparation of large-size titanium-based composite plates particularly difficult. This is mainly related to the following four aspects: (1) Compared with other types of titanium alloys, near-α type high-temperature titanium alloys have a narrower hot working window and higher sensitivity to hot working parameters; (2) The addition of reinforcing phases such as TiB and TiC further increases their hot deformation activation energy, resulting in a significant reduction in the plastic deformation capacity of the composite material; (3) Traditional hot rolling processes, especially when the rolling deformation is large, are accompanied by severe hydrogen and oxygen absorption, which further increases the difficulty of plate preparation and leads to serious deterioration of plate performance; (4) The large-size thin plate rolling process causes severe heat dissipation, resulting in easy deformation and cracking, and low plate forming rate. At present, there are few reports on the research of large-size titanium-based composite plates abroad; and the high-temperature mechanical properties are difficult to meet the requirements of many key aerospace components. Therefore, based on the characteristics of high-temperature titanium-based composites, this invention adopts the cladding and stacking rolling technology to effectively suppress hydrogen absorption, oxygen absorption and heat dissipation, thereby preparing large-size titanium-based composite thin plates with excellent performance. Summary of the Invention

[0004] This invention addresses the problems of severe hydrogen and oxygen absorption and heat dissipation during the rolling process of large-size titanium-based composite material thin plates that can withstand temperatures above 650℃, which lead to easy deformation, cracking, low plate forming rate, and severe deterioration of mechanical properties. It provides a method for preparing large-size high-performance titanium-based composite material thin plates by cladding and rolling.

[0005] A method for preparing a large-size titanium-based composite thin plate resistant to 750℃, specifically comprising the following steps:

[0006] Step 1, Ingot Smelting: This invention uses near-α high-temperature titanium alloy as the matrix, and TiB and TiC as reinforcing phases. After pressing all raw materials into electrodes, they are smelted three times in a vacuum arc remelting furnace to obtain the required large-size titanium-based composite material ingots, which are then annealed and machined.

[0007] Step 2, Rolled Billet Preparation: Multi-directional forging technology is used for forging the billet, with a total deformation of 40%–70%, ultimately obtaining a forged plate of the required specifications. After air cooling to 300℃–500℃, stress-relief annealing is performed. Subsequently, the oxide scale and edge cracks on the surface of the forged billet are removed, and the surface finish of the billet is controlled at Ra6–Ra8; simultaneously, the forged billet is rounded to obtain a rolled billet of the required specifications.

[0008] Step 3, First rolling pre-coating: The billet obtained in Step 2 is coated with a sleeve made of stainless steel or titanium alloy. A heat-resistant glass anti-oxidation coating is applied between the sleeve material and the titanium-based composite forging billet. The ratio of the billet thickness to the sleeve material thickness is 3 to 6.

[0009] Step 4, First rolling pass: The billet described in Step 3 is placed in a heating furnace and heated to 20°C–50°C above the β-phase transformation temperature, and held for 2.0h–4.0h. Subsequently, the billet is placed on a rolling mill for rolling at a rolling speed of 0.05m / s–0.5m / s, with a deformation per pass of 10%–50% and a total deformation of 60%–80%, followed by air cooling to room temperature.

[0010] Step 5: Remove the cladding from the first rolling pass: Remove the cladding from the rolled sheet obtained in Step 4 using machining methods to obtain a titanium-based composite material rolled sheet. Simultaneously, prepare the billet for the next rolling pass using machining methods.

[0011] Step 6, cladding before the second rolling: The rolled billet obtained in Step 5 is clad, and the cladding material is stainless steel or titanium alloy. A heat-resistant glass anti-oxidation coating is applied between the cladding material and the rolled billet. The ratio of the thickness of the rolled plate to the thickness of the cladding material is 0.5 to 3.

[0012] Step 7, Second rolling: The billet described in Step 6 is placed in a heating furnace and heated to 10°C–30°C below the β-phase transformation temperature, and held for 1.0h–3.0h. Subsequently, the billet is placed on a rolling mill for rolling at a rolling speed of 0.05m / s–0.5m / s, with a deformation per pass of 10%–45% and a total deformation of 50%–80%, followed by air cooling to room temperature.

[0013] Step 8, Remove the cladding from the second rolling pass: Remove the cladding from the rolled sheet obtained in Step 7 using machining methods to obtain a titanium-based composite material rolled sheet. Simultaneously, prepare the billet for the next rolling pass using machining methods.

[0014] Step nine: Repeat steps six, seven, and eight until the plate thickness is less than 10mm-20mm. Considering the mechanical properties and cost of the plate, the number of rolling passes should generally not exceed four.

[0015] Step 10, Pre-rolling cladding treatment: Simultaneously clad the 2 to 4 billets obtained in Step 9. The cladding material is stainless steel or titanium alloy. A heat-resistant glass anti-oxidation coating is applied between the cladding material and the titanium-based composite material. Mo sheets are selected as the isolation material between the titanium-based composite materials. The ratio of the total thickness of the billet to the thickness of the cladding material is 0.5 to 2.

[0016] Step 11, Encasing Rolling: The billet described in Step 10 is placed in a heating furnace and heated to 10°C–30°C below the β-phase transformation temperature, and held for 1.5–2.0 hours. Subsequently, the billet is placed on a rolling mill for rolling at a rolling speed of 0.05 m / s–0.5 m / s, with a deformation per pass of 10%–45% and a total deformation of 50%–80%, followed by air cooling to room temperature.

[0017] Step 12: Annealing of the rolled plate: Anneal the rolled plate of the target size obtained in Step 11, as follows: heat to 600℃~900℃ at a heating rate of 10℃ / min~20℃ / min, hold for 1.0h~3.0h and then furnace cool to room temperature.

[0018] Step 13: Remove the cladding from the rolled sheet: Remove the cladding from the rolled sheet obtained in Step 12 using a machining method to obtain the target titanium-based composite material rolled sheet.

[0019] The advantages and beneficial effects of this invention are as follows:

[0020] I. This invention provides a method for preparing large-size titanium-based composite material thin plates resistant to 750℃ by cladding and rolling. By scientifically designing the ratio of billet thickness to cladding material thickness and hot rolling process parameters, the matching between billet and cladding material is significantly improved, thereby avoiding problems such as plate deformation and cracking, and greatly increasing the forming rate of large-size thin plates.

[0021] Second, the sheathing rolling process can effectively suppress hydrogen absorption, oxygen absorption, and severe heat dissipation, ensuring that the mechanical properties of the sheet are at a high level.

[0022] Third, the hot rolling process for large-size thin plates provided by this invention is simple and stable, and can efficiently produce high-quality large-size titanium-based composite material thin plates, thus better meeting the requirements of industrial production. Attached Figure Description

[0023] Figure 1 The macroscopic morphology of the slab before removing the cladding after cladding stacking in Example 1;

[0024] Figure 2 This is the macroscopic morphology of the sheet material after the cladding was removed following the cladding stacking in Example 1. Detailed Implementation

[0025] To further illustrate the advantages, technical solutions, and objectives of the present invention, the following detailed description, in conjunction with specific embodiments, further explains the solutions of the present invention. It should be noted that the specific embodiments of the present invention are merely illustrative and not limited to the following examples. Any person skilled in the art, after understanding the embodiments of the present invention, can make changes and modifications based on the techniques taught in the present invention, without departing from the spirit and scope of the present invention.

[0026] Example 1:

[0027] A method for preparing large-size, high-performance titanium-based composite thin plates by cladding and rolling is specifically carried out according to the following steps:

[0028] I. Ingot Smelting: This invention uses near-α high-temperature titanium alloy as the matrix, and TiB and TiC as reinforcing phases. After pressing all raw materials into electrodes, they are smelted three times in a vacuum arc remelting furnace to obtain... Large-sized titanium-based composite material ingots, weighing approximately 180 kg, were produced. The volume ratio of TiB to TiC was 1:1, with a combined volume fraction of 2.5%. Subsequently, annealing and machining were performed to ensure complete removal of large macroscopic pores on the ingot surface. The ingot annealing process was as follows: the temperature was increased to 800℃ at a rate of 15℃ / min, held at that temperature for 24 hours, and then furnace cooled to room temperature.

[0029] II. Preparation of Rolled Billet: Multi-directional forging technology was used for forging the billet, with a total deformation of 50%, ultimately obtaining a forged plate of the required specifications. After air cooling to approximately 300℃, stress-relief annealing was performed. The stress-relief annealing process for the forged billet was as follows: heating to 700℃ at a rate of 15℃ / min, holding at that temperature for 12 hours, and then furnace cooling to room temperature. Subsequently, the oxide scale and edge cracks on the surface of the forged billet were removed, and the surface finish of the billet was approximately Ra6. Simultaneously, the forged billet was rounded, ultimately obtaining a rolled billet of 683mm × 240mm × 104mm.

[0030] Third, the billet before the first rolling: The billet obtained in step two is wrapped with a 304 stainless steel liner. A heat-resistant glass anti-oxidation coating is applied between the liner material and the titanium-based composite forging billet. The ratio of the billet thickness to the liner material thickness is 5.

[0031] IV. First rolling pass: The billet described in step five is placed in a heating furnace and heated to 1060°C, and held for 4.0 hours. Subsequently, the billet is placed on a rolling mill for rolling at a rolling speed of 0.1 m / s, with a deformation per pass of 15% to 30% and a total deformation of 76%. It is then air-cooled to room temperature.

[0032] 5. Removal of the first rolling mill cladding: The cladding on the rolled plate obtained in step 4 is removed by machining to obtain a titanium-based composite material rolled plate of 1100mm × 870mm × 25mm. Simultaneously, a billet for the next rolling mill is prepared, with specific dimensions of 968mm × 860mm × 24mm.

[0033] VI. Encasing before the second rolling: The rolled billet obtained in step 5 is encased in a 304 stainless steel liner. A heat-resistant glass anti-oxidation coating is applied between the liner material and the titanium-based composite material plate. The ratio of the plate thickness to the liner material thickness is 2.

[0034] VII. Second rolling: The billet described in step VI is placed in a heating furnace and heated to 1010℃, held for 2.0 hours. Subsequently, the billet is placed on a rolling mill for rolling at a rolling speed of 0.1 m / s, with a deformation per pass of 11% to 40% and a total deformation of 75%, and then air-cooled to room temperature.

[0035] 8. Removal of the cladding from the second rolling pass: The cladding on the rolled sheet obtained in step 9 is removed by machining to obtain a 3300mm×970mm×6.5mm titanium-based composite material rolled sheet. Simultaneously, the obtained rolled sheet is divided into four pieces to prepare the billet for the next rolling pass, with specific dimensions of 700mm×680mm×6mm.

[0036] 9. Encasing before stacking: The three rolled billets obtained in step 8 are simultaneously encased. The encasing material is 304 stainless steel. A heat-resistant glass anti-oxidation coating is applied between the encasing material and the titanium-based composite material. Mo sheets are selected as the isolation material between the titanium-based composite materials. The ratio of the thickness of the rolled plate to the thickness of the encasing material is 0.5.

[0037] 10. Encasing and Rolling: The billet encased in titanium-based composite material as described in step 9 is placed in a heating furnace and heated to 1010°C, held for 2.0 hours. Subsequently, the billet is placed on a rolling mill for rolling at a rolling speed of 0.1 m / s, with a per-pass deformation of 15%–40% and a total deformation of 65%, and then air-cooled to room temperature.

[0038] XI. Annealing treatment of the target rolled plate: The rolled plate obtained in step ten is annealed as follows: the temperature is increased to 700℃ at a heating rate of 15℃ / min, held at that temperature for 1.5h, and then furnace cooled to room temperature.

[0039] 12. Remove the cladding from the rolled sheet: Remove the cladding from the rolled sheet obtained in step 11 using a machining method to obtain a titanium-based composite material rolled sheet with the target dimensions: 2060mm×680mm×2.0mm.

[0040] The macroscopic morphology of the slab before and after removing the cladding after cladding stacking is as follows: Figure 1 and Figure 2 As shown.

Claims

1. A method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃, characterized in that, Follow these steps: Step 1, Ingot smelting: Near-α high-temperature titanium alloy is selected as the matrix, and TiB and TiC are used as reinforcing phases; after all raw materials are pressed into electrodes, they are smelted three times in a vacuum arc furnace to obtain the required large-size titanium-based composite material ingots, which are then annealed and machined. Step 2, Preparation of rolled billet: The ingot is forged and opened, and then stress-relief annealing is performed; then, the oxide scale and edge cracks on the surface of the forging billet are removed, and the forging billet is rounded to obtain the rolled billet of the required specifications. The ingot forging process employs multi-directional forging technology, with a total deformation of 40% to 70%, ultimately yielding a forged billet of the required specifications. After air cooling to 300°C to 500°C, stress-relief annealing is performed. The surface finish of the billet is controlled at Ra6 to Ra8. Step 3, First rolling pre-coating: The billet obtained in Step 2 is coated with a sleeve made of stainless steel or titanium alloy. A heat-resistant glass anti-oxidation coating is applied between the sleeve material and the titanium-based composite forging billet. Step 4, First rolling: The billet described in Step 3 is placed in a heating furnace and heated. Then, the billet is placed on a rolling mill for rolling. Step 5, Remove the first rolling sleeve: Remove the sleeve from the rolled plate with sleeve obtained in Step 4 using a machining method to obtain a titanium-based composite material rolled plate; at the same time, prepare the billet for the next rolling process using a machining method. Step 6, Encasing before the second rolling: The rolled billet obtained in Step 5 is encased in a sleeve made of stainless steel or titanium alloy, and a heat-resistant glass anti-oxidation coating is applied between the sleeve material and the rolled billet. Step 7, Second rolling: The billet described in Step 6 is placed in a heating furnace and heated. Then, the billet is placed on a rolling mill for rolling. Step 8, Remove the cladding from the second rolling pass: Remove the cladding from the rolled plate obtained in Step 7 using machining methods to obtain a titanium-based composite material rolled plate; at the same time, prepare the billet for the next rolling pass using machining methods. Step 9: Repeat steps 6, 7, and 8 until the plate thickness is less than 10mm~20mm; considering the mechanical properties and cost of the plate, the number of rolling passes should generally not exceed 4. Step 10, Pre-rolling cladding treatment: The multiple billets obtained in Step 9 are clad simultaneously. The cladding material is stainless steel or titanium alloy. A heat-resistant glass anti-oxidation coating is applied between the cladding material and the titanium-based composite material. Mo sheets are selected as the isolation material between the titanium-based composite materials. Step 11, Encasing and Rolling: The billet described in Step 10 is placed in a heating furnace and heated. Then, the billet is placed on a rolling mill for rolling. Step 12: Annealing of the rolled plate: Anneal the rolled plate of the target dimensions obtained in Step 11; Step 13: Remove the cladding from the rolled sheet: Remove the cladding from the rolled sheet obtained in Step 12 using a machining method to obtain the target titanium-based composite material rolled sheet.

2. The method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃ according to claim 1, characterized in that, In step three, the ratio of the billet thickness to the thickness of the cladding material before the first rolling is 3 to 6.

3. The method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃ according to claim 1, characterized in that, In step four, the billet is placed in a heating furnace and heated to 20°C to 50°C above the β phase transformation temperature, and held for 2.0h to 4.0h; the rolling speed is 0.05m / s to 0.5m / s, the deformation per pass is 10% to 50%, the total deformation is 60% to 80%, and it is air-cooled to room temperature.

4. The method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃ according to claim 1, characterized in that, In step six, the ratio of the billet thickness to the thickness of the cladding material before the second rolling is 0.5 to 3.

5. The method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃ according to claim 1, characterized in that, In step seven, the furnace temperature is raised to 10°C to 30°C below the β-phase transformation temperature and held for 1.0h to 3.0h. Subsequently, the billet is placed on a rolling mill for rolling at a rolling speed of 0.05m / s to 0.5m / s, with a deformation per pass of 10% to 45% and a total deformation of 50% to 80%. The billet is then air-cooled to room temperature.

6. The method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃ according to claim 1, characterized in that, In step ten, 2 to 4 billets are simultaneously encased, and the ratio of the total thickness of the billets to the thickness of the encasing material is 0.5 to 2.

7. The method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃ according to claim 1, characterized in that, In step eleven, the cladding and stacking billet is heated in the furnace to 10℃~30℃ below the β phase transformation temperature and held for 1.5h~2.0h; the rolling speed is 0.05m / s~0.5m / s, the deformation per pass is 10%~45%, the total deformation is 50%~80%, and it is air-cooled to room temperature.

8. The method for cladding and laminating large-size titanium-based composite thin plates resistant to 750℃ according to claim 1, characterized in that, In step twelve, the annealing temperature of the thin plate is 600℃~900℃, and the holding time is 1.0h~3.0h.

9. A large-size titanium-based composite material thin plate resistant to 750℃, characterized in that, The method of cladding and rolling as described in claim 1.

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