Surface treatment method for titanium and titanium alloy blocky recycled materials
By sorting and treating titanium and titanium alloy bulk materials, using the combination of alkali explosion, shot blasting and pickling, the problem of difficulty in taking into account low cost, high quality and high efficiency in the prior art is solved, and an efficient and low-cost surface treatment effect is achieved.
Patent Information
- Application Number
- CN202510518475.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2025-05-30
AI Technical Summary
Existing titanium alloy surface treatment technology is difficult to balance low cost, high quality and high efficiency, especially in large-scale industrial production.
By dividing titanium and titanium alloy bulk materials into two categories, using alkaline explosion treatment and shot blasting treatment combined with pickling treatment, the different types of materials are personalized to improve the surface treatment efficiency and quality.
It achieves efficient removal of oxide scale, improves the surface quality of block materials, reduces energy consumption and costs, and is suitable for large-scale industrial production.
Smart Images
Figure CN120060665A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of titanium alloy surface treatment, and particularly relates to a surface treatment method for titanium and titanium alloy bulk recycled materials. Background Art
[0002] With the substantial increase in the application scope and consumption of titanium and titanium alloys, the recycled materials in the product production process have gradually increased. Recycling the recycled materials after treatment has become an effective means of energy conservation and cost reduction. The recycled materials include ingot heads, billet heads, bar ends, etc. generated during production and processing such as melting, forging, and hot rolling. Their surface quality is poor, uneven, with severe cracks and oxidation, and the oxide scale on the surface is difficult to remove; the recycled materials also include the cut-off scraps during machining due to processing requirements, as well as products that do not meet the quality standards for various reasons; and the residual parts such as welding slag, welding heads, and welding tails generated during the welding process. The surfaces of these recycled materials all have varying degrees of oxide scale and oil stains. Therefore, when recycling titanium and titanium alloy bulk materials, it is necessary to process their surfaces to improve the performance of the bulk materials and facilitate subsequent processing.
[0003] Due to the different states of the titanium alloy oxide scale, such as thickness, composition, and compactness, there are various methods for the existing technology to remove the oxide scale. Common methods for removing the oxide scale include: Chemical pickling method: Using a mixed acid pickling solution of nitric acid and hydrofluoric acid can effectively remove the oxide scale, but there are risks of hydrofluoric acid toxicity and hydrogen embrittlement. Mechanical grinding method: Removing the oxide scale by mechanical force, but with low efficiency and large damage to the substrate. Electrochemical treatment method: Using an electrochemical reaction to remove the oxide scale, but the equipment is complex and the cost is high. Among these methods, the chemical pickling method has high efficiency, but cost and safety issues limit its wide application; while mechanical grinding and electrochemical treatment are relatively safe, but have low efficiency and are difficult to meet the requirements of large-scale industrial production. Therefore, the existing technology for removing the oxide scale has the problem that it is difficult to balance low cost, high quality, and high efficiency. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a surface treatment method for titanium and titanium alloy bulk recycled materials in view of the above deficiencies in the existing technology. The design is novel and reasonable, with high surface treatment quality and easy to promote and use.
[0005] To solve the above technical problems, the technical solution adopted by the present invention is: A surface treatment method for titanium and titanium alloy bulk recycled materials, the method comprising the following steps: Step 1: Classify the bulk materials to be treated into the first type of materials and the second type of materials according to the surface state of the bulk materials. The first type of materials has oxide scale on the surface and the oxide scale has bottom-reaching cracks or cavities, and the second type of materials has oxide scale on the surface and the oxide scale has no bottom-reaching cracks and cavities; Step 2: Shot peening treatment is carried out on the second type of material. The first type of material and the second type of material after shot peening treatment are respectively hung on different workpiece racks; the first type of material is successively subjected to alkali explosion treatment and pickling treatment; the second type of material is subjected to pickling treatment; The process of the alkali explosion treatment is as follows: soak the massive material in the alkali solution at the first temperature, and start air stirring, lasting for 6 min to 12 min, raise the temperature to the second temperature, and keep it for 10 min to 30 min, then perform water explosion on the massive material to complete the alkali explosion operation; observe the degree of alkali explosion of the oxide scale on the massive material, perform the alkali explosion operation again on the massive material that does not meet the alkali explosion requirements, and perform circulating water washing on the massive material that meets the alkali explosion requirements; the second temperature is higher than the first temperature; The process of the pickling treatment is as follows: soak the massive material in the first acid solution at the third temperature, and start air stirring and keep it for 1 min to 3 min to complete the first pickling. Soak the massive material in the second acid solution at the third temperature, and start air stirring and keep it for 3 min to 10 min to complete the second pickling. Soak the massive material in the third acid solution at the fourth temperature for 2 min to 6 min to complete the third pickling, and then perform circulating water washing on the massive material. Observe whether the oxide scale on the surface of the massive material is completely removed. If the oxide scale on the surface of the massive material is completely removed, proceed to the next step; otherwise, repeat the pickling treatment once; Step 3: Dry the massive material, and the drying temperature is 60 °C to 150 °C. Then remove the massive material from the workpiece rack and recycle and store it according to the first type of material and the second type of material respectively.
[0006] Further, in Step 2, the first temperature is 60 °C to 80 °C, the second temperature is 420 °C to 530 °C, and the alkali solution is prepared according to the first volume ratio from a sodium hydroxide solution with a volume concentration of 80% to 90% and a sodium nitrate solution with a volume concentration of 5% to 15%; the first volume ratio is 100: (5 - 10).
[0007] Further, in Step 2, the first acid solution is prepared according to the second volume ratio from a hydrofluoric acid solution with a volume concentration of 1% to 7% and a nitric acid solution with a volume concentration of 10% to 30%, or is a hydrochloric acid solution with a volume concentration of 5% to 9%; the second acid solution is prepared according to the second volume ratio from a hydrofluoric acid solution with a volume concentration of 1% to 7% and a nitric acid solution with a volume concentration of 10% to 30%; the third acid solution is a sulfuric acid solution with a volume concentration of 3% to 6%; the second volume ratio is 1: (6 - 10).
[0008] Further, in step 2, before pickling treatment, the thickness of the oxide layer of the bulk material is detected. When the thickness of the oxide layer of the bulk material is less than or equal to 1 μm, the volume concentration of the hydrofluoric acid solution in the first acid solution and the second acid solution is 1% - 3%. When the thickness of the oxide layer of the bulk material is greater than 1 μm, the volume concentration of the hydrofluoric acid solution in the first acid solution and the second acid solution is 3% - 7%.
[0009] Further, in step 2, the third temperature is 15°C - 35°C, and the fourth temperature is 15°C - 25°C.
[0010] Further, after shot blasting treatment, the surface of the bulk material is purged by a high-pressure blower.
[0011] Further, the bulk material to be processed includes the casting risers and corner pieces of titanium and titanium alloys. The diameter of the casting riser is 100 mm - 1000 mm, and the thickness is 10 mm - 50 mm. The length of the corner piece is 500 mm - 2500 mm, the width is 20 mm - 1000 mm, and the thickness is 5 mm - 100 mm.
[0012] The present invention has the following advantages compared with the prior art: By classifying the surfaces of the bulk materials into two categories and adopting different treatment methods for bulk materials with different pollution degrees, the present invention improves the surface treatment efficiency and optimizes the surface quality. Specifically, for bulk materials with less surface pollution and easy to process (the first type of materials), alkali explosion treatment is adopted; the surface quality after this method is relatively high. For bulk materials with heavier surface pollution (the second type of materials), shot blasting treatment is adopted; this method has higher treatment efficiency, but the surface after treatment is relatively rough. By selecting a suitable treatment method for the bulk materials, the present invention improves the surface treatment efficiency while optimizing the surface quality. During the alkali explosion treatment, first, a low-temperature alkali solution is used to gently treat the surface of the bulk material, and then a high-temperature alkali solution is used for efficient treatment. This staged treatment method gives full play to the mildness of the low-temperature treatment and the high efficiency of the high-temperature treatment, while optimizing the surface quality of the bulk material and reducing energy consumption and costs. In addition, after alkali explosion or shot blasting treatment, the present invention also adds pickling treatment as a subsequent fine treatment step. By first removing most of the oxide layer and then pickling, the overall process efficiency is higher; it solves the problem in the prior art that it is difficult to balance low cost, high quality, and high efficiency.
[0013] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings
[0014] Figure 1 It is a schematic diagram of the surface treatment process of the first type of materials in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 2 Schematic diagram of the surface treatment process of the second type of material in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 3 Schematic diagram of the surface morphology of the first type of material before treatment in Example 1 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 4 Schematic diagram of the surface morphology of the first type of material after treatment in Example 1 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 5 Schematic diagram of the surface morphology of the second type of material before treatment in Example 1 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 6 Schematic diagram of the surface morphology of the second type of material after treatment in Example 1 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 7 Schematic diagram of the surface morphology of the first type of material before treatment in Example 2 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 8 Schematic diagram of the surface morphology of the first type of material after treatment in Example 2 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 9 Schematic diagram of the surface morphology of the second type of material before treatment in Example 2 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention; Figure 10 Schematic diagram of the surface morphology of the second type of material after treatment in Example 2 in the embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials of the present invention. Detailed implementation manners
[0015] Embodiment of the surface treatment method for titanium and titanium alloy bulk recycled materials: As Figure 1 、 Figure 2 shown, in step 1, the bulk materials to be treated are divided into the first type of material and the second type of material according to the surface state of the bulk materials. The first type of material is the one with scale on the surface and bottom-reaching cracks or cavities in the scale, and the second type of material is the one with scale on the surface and no bottom-reaching cracks and cavities.
[0016] The above-mentioned bulk materials to be treated include the casting risers and corner block materials of titanium and titanium alloy. The diameter of the above-mentioned casting risers is 100 mm to 1000 mm, and the thickness is 10 mm to 50 mm; the length of the above-mentioned corner block materials is 500 mm to 2500 mm, the width is 20 mm to 1000 mm, and the thickness is 5 mm to 100 mm. The bulk materials also include plates, rods, tubes, titanium alloy parts, ingot heads, etc.
[0017] Step 2: Shot blast the second type of material, and hang the first type of material and the shot-blasted second type of material on different workpiece racks respectively; successively perform alkaline explosion treatment and pickling treatment on the first type of material; perform pickling treatment on the second type of material. After shot blasting, use a high-pressure blower to blow the surface of the massive material. During shot blasting, generally, manual inspection is carried out to check whether the shot blasting is qualified, and only after passing the inspection can it enter the next step.
[0018] The process of the above alkaline explosion treatment is as follows: Immerse the massive material in the alkaline solution at the first temperature, and start air stirring for 6 min to 12 min. Then raise the temperature to the second temperature and keep it for 10 min to 30 min. Subsequently, perform water explosion on the massive material to be treated to complete the alkaline explosion operation; observe the degree of alkaline explosion of the oxide scale on the massive material, and perform the alkaline explosion operation again on the massive material that does not meet the alkaline explosion requirements. For the massive material that meets the alkaline explosion requirements, perform circulating water washing; the second temperature is higher than the first temperature. By air stirring, the alkaline solution can be fully contacted with the surface of the massive material to accelerate the reaction. In addition, it can also make the composition of the alkaline solution uniform, thereby improving the efficiency of alkaline explosion treatment. Through the reaction between the alkaline solution and the surface of the titanium alloy, the surface oxide layer expands and peels off rapidly at high temperature, so as to achieve the purpose of cleaning and activating the surface.
[0019] To ensure the efficiency of alkaline explosion treatment, the first temperature is 60°C to 80°C, the second temperature is 420°C to 530°C, and the above alkaline solution is prepared by mixing sodium hydroxide solution with a volume concentration of 80% to 90% and sodium nitrate solution with a volume concentration of 5% to 15% according to the first volume ratio; the first volume ratio is 100:(5 - 10). By adding sodium nitrate to the alkaline solution, the surface activity of the alkaline solution can be changed, and the reaction can be promoted in the direction beneficial to peeling off the oxide layer. The reaction rate between the alkaline solution and the surface of the titanium alloy is moderate, which can not only effectively remove the oxide layer but also better control the reaction degree.
[0020] The process of this pickling treatment is as follows: Immerse the massive material in the first pickling solution at the third temperature and start air stirring for 1 min to 3 min to complete the first pickling. Then immerse the massive material in the second pickling solution at the third temperature and start air stirring for 3 min to 10 min to complete the second pickling. Then immerse the massive material in the third pickling solution at the fourth temperature for 2 min to 6 min to complete the third pickling. Subsequently, perform circulating water washing on the massive material, and observe whether the oxide scale on the surface of the massive material is removed cleanly. If the oxide scale on the surface of the massive material is removed cleanly, it enters the next step; otherwise, repeat the pickling treatment once; the above third temperature is 15°C to 35°C, and the fourth temperature is 15°C to 25°C. It is equivalent to performing pickling three times.
[0021] The first acid solution is prepared from a hydrofluoric acid solution with a volume concentration of 1% - 7% and a nitric acid solution with a volume concentration of 10% - 30% according to a second volume ratio, or is a hydrochloric acid solution with a volume concentration of 5% - 9%. Both of these acid solutions can be used for the first pickling. The second acid solution is prepared from a hydrofluoric acid solution with a volume concentration of 1% - 7% and a nitric acid solution with a volume concentration of 10% - 30% according to the second volume ratio. The second volume ratio is 1:(6 - 10). This mixed acid solution can effectively remove the oxide layer, impurities, etc. on the surface of the titanium alloy, and nitric acid can, to a certain extent, inhibit the excessive corrosion of the hydrofluoric acid on the titanium alloy.
[0022] The third acid solution is a sulfuric acid solution with a volume concentration of 3% - 6%. Sulfuric acid can enhance the ability of the acid solution to remove the oxide layer on the surface of the titanium alloy. The composition of the oxide layer on the surface of the titanium alloy is relatively complex, and sulfuric acid can react with some of the oxides therein to dissolve them, thereby effectively removing the oxide layer. In the mixed acid system, sulfuric acid can adjust the overall activity of the acid solution. The sulfuric acid aqueous solution can be used to clean the impurities remaining on the surface of the titanium alloy during alkali washing or other processing.
[0023] To further reduce the cost of pickling treatment, for a slightly oxidized layer, a hydrofluoric acid solution with a relatively small volume concentration can be selected, and for a relatively thick oxidized layer, a hydrofluoric acid solution with a relatively high volume concentration can be selected. When the thickness of the oxide layer of the bulk material is less than or equal to 1 μm, the volume concentration of the hydrofluoric acid solution in the first acid solution and the second acid solution is 1% - 3%, and when the thickness of the oxide layer of the bulk material is greater than 1 μm, the volume concentration of the hydrofluoric acid solution in the first acid solution and the second acid solution is 3% - 7%. The thickness of the oxide layer of this bulk material can be measured by a handheld coating thickness gauge using the sensitive eddy current method, which is a non-destructive measurement method; or an X-ray fluorescence thickness gauge can be selected to measure the thickness of the oxide layer of the bulk material. Hydrofluoric acid has strong corrosiveness and toxicity, so being able to reduce the addition amount of the hydrofluoric acid solution can ensure the safety of the surface treatment of the bulk material.
[0024] Step 3: Dry the bulk material at a drying temperature of 60°C - 150°C, and then remove the bulk material from the workpiece hanger and store it separately according to the first type of material and the second type of material.
[0025] Taking the treatment of corner bulk materials as an example, treat them according to the above surface treatment method for titanium and titanium alloy bulk recycled materials; first, divide the bulk materials to be treated into the first type of material and the second type of material according to the surface conditions. Since basically all the materials in the same batch are the first type of material or the second type of material, in this embodiment, the first type of material and the second type of material are respectively selected from two batches of materials.
[0026] Example 1: Such as Figures 3 - 6As shown, the first type of material is subjected to alkali explosion treatment and pickling treatment, and the second type of material is subjected to shot peening treatment and pickling treatment. First, the first type of material is subjected to alkali explosion treatment. The massive material is immersed in an alkali solution at 60°C for 6 minutes, the temperature is raised to 480°C and maintained for 10 minutes, and then transferred to a water explosion tank for water explosion treatment, followed by circulating water washing; the alkali solution is prepared from a sodium hydroxide solution with a volume concentration of 80% and a sodium nitrate solution with a volume concentration of 10% in a volume ratio of 100:5. At the same time, the second type of material is subjected to shot peening treatment.
[0027] The thickness of the oxide layer of the massive material after alkali explosion treatment or shot peening treatment is detected, and its thickness is less than 1 μm.
[0028] Then, the first type of material and the second type of material are subjected to pickling treatment. It is treated in the first pickling solution at 20°C for 3 minutes, then treated in the second pickling solution at 20°C for 3 minutes, and then treated in a sulfuric acid solution with a volume concentration of 4% at 25°C; among them, both the first pickling solution and the second pickling solution are prepared from a hydrofluoric acid solution with a volume concentration of 3% and a nitric acid solution with a volume concentration of 20% in a volume ratio of 1:6.
[0029] The massive material is dried at a drying temperature of 80°C, and then the massive material is recycled and stored separately according to the first type of material and the second type of material; the drying is carried out by hot air blowing.
[0030] Example 2: As Figures 7 - 10 shown, the first type of material is subjected to alkali explosion treatment and pickling treatment, and the second type of material is subjected to shot peening treatment and pickling treatment. First, the first type of material is subjected to alkali explosion treatment. The massive material is immersed in an alkali solution at 80°C for 6 minutes, the temperature is raised to 420°C and maintained for 12 minutes, and then transferred to a water explosion tank for water explosion treatment, followed by circulating water washing; the alkali solution is prepared from a sodium hydroxide solution with a volume concentration of 85% and a sodium nitrate solution with a volume concentration of 5% in a volume ratio of 100:8. At the same time, the second type of material is subjected to shot peening treatment.
[0031] The thickness of the oxide layer of the massive material after alkali explosion treatment or shot peening treatment is detected, and its thickness is less than 1 μm.
[0032] Then, the first type of material and the second type of material are subjected to pickling treatment. It is treated in the first pickling solution at 20°C for 3 minutes, then treated in the second pickling solution at 20°C for 3 minutes, and then treated in a sulfuric acid solution with a volume concentration of 4% at 25°C; among them, both the first pickling solution and the second pickling solution are prepared from a hydrofluoric acid solution with a volume concentration of 3% and a nitric acid solution with a volume concentration of 10% in a volume ratio of 1:10.
[0033] The bulk materials are dried at a temperature of 100 °C, and then the bulk materials are respectively recycled and stored according to the first-class materials and the second-class materials; the drying is carried out by hot air blowing.
[0034] Observe the surface morphologies of the bulk materials after being processed in Example 1 and Example 2, as Figures 3 - 10 shown, the surface presents a metallic luster and there is no obvious oxide residue. Among them, Figure 3 and Figure 7 are schematic diagrams of the bulk materials when they are not hung, and Figure 5 and Figure 9 are schematic diagrams of the bulk materials when they are hung. Hanging refers to: in order to facilitate the treatment of the surface of the bulk materials, the bulk materials are suspended on the conveying device of the production line through a jig.
[0035] By means of the process of first treating with low-temperature lye and then treating with high-temperature lye, the mildness of the low-temperature treatment and the high efficiency of the high-temperature treatment can be fully exerted. At the same time, the surface quality is optimized, the energy consumption and cost are reduced, and the adaptability and flexibility of the process are improved. This phased treatment method has significant advantages in industrial production, especially suitable for the treatment of bulk materials with high surface quality requirements. The above are only the preferred embodiments of the present invention, and do not impose any limitations on the present invention. Any simple modifications, changes, and equivalent structural changes made to the above embodiments according to the technical essence of the present invention still fall within the protection scope of the technical solution of the present invention.
Claims
1. A surface treatment method for titanium and titanium alloy block recycled materials, characterized in that: The method comprises the following steps: Step 1, dividing the bulk material to be processed into a first type of material and a second type of material according to the surface state of the bulk material, the first type of material having oxide scale on the surface and the oxide scale having bottom-viewing cracks or cavities, and the second type of material having oxide scale on the surface and the oxide scale having no bottom-viewing cracks and cavities; Step 2, shot blasting the second type of material, hanging the first type of material and the second type of material after shot blasting on different workpiece hangers respectively; performing alkali explosion treatment and pickling treatment on the first type of material in turn; performing pickling treatment on the second type of material; The alkali explosion treatment process is as follows: soaking the block material in an alkali solution at a first temperature, and starting air stirring for 6 to 12 minutes, raising the temperature to a second temperature for 10 to 30 minutes, and then water-exploding the block material to complete the alkali explosion operation; observing the alkali explosion degree of the block material oxide scale, performing alkali explosion operation again on the block material that does not meet the alkali explosion requirements, and performing circulating water washing on the block material that meets the alkali explosion requirements; the second temperature is greater than the first temperature; The pickling process is as follows: immersing the block material in a first acid solution at a third temperature, and turning on air stirring for 1 to 3 minutes to complete the first pickling, immersing the block material in a second acid solution at the third temperature, and turning on air stirring for 3 to 10 minutes to complete the second pickling, immersing the block material in a third acid solution at a fourth temperature for 2 to 6 minutes to complete the third pickling, and then washing the block material with circulating water to observe whether the oxide scale on the surface of the block material is completely removed. If the oxide scale on the surface of the block material is completely removed, proceed to the next step, otherwise, repeat the pickling process once; Step 3: Dry the block material at a temperature of 60°C to 150°C, then remove the block material from the workpiece rack and recycle and store it separately according to the first type of material and the second type of material.
2. A surface treatment method for titanium and titanium alloy block recycled materials according to claim 1, characterized in that: In step 2, the first temperature is 60°C to 80°C, the second temperature is 420°C to 530°C, and the alkali solution is prepared by a first volume ratio of a sodium hydroxide solution with a volume concentration of 80% to 90% and a sodium nitrate solution with a volume concentration of 5% to 15%; the first volume ratio is 100:(5-10).
3. A surface treatment method for titanium and titanium alloy block recycled materials according to claim 1, characterized in that: In step 2, the first acid solution is prepared by a hydrofluoric acid solution with a volume concentration of 1% to 7% and a nitric acid solution with a volume concentration of 10% to 30% according to a second volume ratio, or is a hydrochloric acid solution with a volume concentration of 5% to 9%; the second acid solution is prepared by a hydrofluoric acid solution with a volume concentration of 1% to 7% and a nitric acid solution with a volume concentration of 10% to 30% according to a second volume ratio; the third acid solution is a sulfuric acid solution with a volume concentration of 3% to 6%; the second volume ratio is 1:(6-10).
4. A method for surface treatment of titanium and titanium alloy block recycled materials according to claim 3, characterized in that: In step 2, before the pickling treatment, the thickness of the oxide layer of the block material is detected. When the thickness of the oxide layer of the block material is less than or equal to 1 μm, the volume concentration of the hydrofluoric acid solution in the first acid solution and the second acid solution is 1% to 3%. When the thickness of the oxide layer of the block material is greater than 1 μm, the volume concentration of the hydrofluoric acid solution in the first acid solution and the second acid solution is 3% to 7%.
5. A surface treatment method for titanium and titanium alloy block recycled materials according to claim 1, characterized in that: In step 2, the third temperature is 15°C to 35°C, and the fourth temperature is 15°C to 25°C.
6. A surface treatment method for titanium and titanium alloy block recycled materials according to claim 1, characterized in that: After the shot blasting, the surface of the block material is purged by a high-pressure blower.
7. A method for surface treatment of titanium and titanium alloy block recycled materials according to claim 1, characterized in that: The block materials to be processed include casting heads and corner blocks of titanium and titanium alloys. The diameter of the casting heads is 100mm to 1000mm and the thickness is 10mm to 50mm; the length of the corner blocks is 500mm to 2500mm, the width is 20mm to 1000mm, and the thickness is 5mm to 100mm.