Free-cutting titanium alloy wire and preparation method thereof
By designing the components of titanium alloy ingots and combining forging, rolling and heat treatment processes, high-performance easy-to-cut titanium alloy wires are prepared, which solves the problem of poor cutting performance of titanium alloys and achieves cost reduction and accuracy improvement.
Patent Information
- Application Number
- CN202510098459.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-05-02
AI Technical Summary
The poor cutting performance of titanium alloys leads to high processing costs and unavailable accuracy, which limits its commercial application.
By designing the components of the titanium alloy ingot and combining with appropriate forging and rolling processes and heat treatment processes, easy-to-cut titanium alloy wires with tensile strength ≥770MPa, yield strength ≥700MPa, elongation ≥23%, and Brinell hardness ≥270 were prepared.
It significantly improves the cutting performance of titanium alloy wires, reduces processing costs, and ensures processing accuracy, and has far exceeded the TA4 index.
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Figure CN119913382A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of titanium alloy processing, and in particular, relates to a free-cutting titanium alloy wire and a preparation method thereof. Background Art
[0002] Titanium has the advantages of low density, high strength, good corrosion resistance and high specific strength. It is widely used in aerospace, shipbuilding, seawater power generation, chemical metallurgy, automobile, biomedicine, 3C and other fields. However, due to the poor cutting performance of titanium and titanium alloys, not only the processing cost is too high, but also the processing accuracy cannot be guaranteed, which limits the commercial application of titanium and its alloys. Therefore, how to improve the cutting performance of titanium alloy is an urgent problem to be solved. Summary of the invention
[0003] In order to overcome the defects of the above-mentioned prior art, the present application designs the composition of the titanium alloy ingot and matches the appropriate forging and rolling process and heat treatment process, so that the tensile strength of the titanium alloy wire is ≥770MPa, the yield strength is ≥700MPa, the elongation is ≥23%, the Brinell hardness is ≥270, and the cutting bending moment is 6% lower than that of the TA4 wire.
[0004] To achieve the above objectives, the present application provides a method for preparing a free-cutting titanium alloy wire, comprising:
[0005] Preparation of titanium alloy electrodes;
[0006] Performing vacuum consumable melting on titanium alloy electrodes to obtain ingots;
[0007] Forging the ingot to obtain a billet;
[0008] Rolling the billet to obtain a titanium alloy wire;
[0009] Preparation of titanium alloy electrodes, including:
[0010] According to the mass percentage of each element in the titanium alloy electrode, the total content of Cu, Al and Zr is 0.6-1.2%, the content of Fe is 0.34-0.50%, the content of O is 0.36-0.43%, the content of N is ≤0.05%, the content of H is ≤0.001%, the content of C is ≤0.02%, and the content of Ti is 98%≤≤98.5%.
[0011] Furthermore, the number of vacuum consumable melting is 2-3 times, the melting current fluctuation is ≤1000A / min, the melting voltage fluctuation is ≤2V / min, and the arc stabilizing current fluctuation is ≤1.5A / min.
[0012] Further, the ingot is forged, including:
[0013] The ingot is heated by controlling the temperature to be between 150° C. lower than the phase transition point of the titanium alloy and 200° C. higher than the phase transition point of the titanium alloy;
[0014] The heated ingot is subjected to drawing forging, with each pass deforming by 5% to 50%.
[0015] Further, heating the ingot includes: the cross-sectional thickness of the ingot is ≥600 mm, and the total heating time is ≥480 min;
[0016] For every 1.0 mm increase in the cross-sectional thickness of the ingot, the total heating time increases by 1.0-1.5 min.
[0017] Furthermore, after forging the ingot to obtain a billet, the process includes:
[0018] The blank is ground and inspected to eliminate surface defects.
[0019] Further, the billet is rolled, including:
[0020] The billet is heated and rolled at 100-150°C below the phase transition point of the titanium alloy, the cross-sectional thickness of the billet is ≥140mm, the heating time is ≥140min, and the heating time is increased by 1min for every increase of 1.0-2.0mm in the cross-sectional thickness of the billet;
[0021] The heated billet is rolled into titanium alloy wire at room temperature by multi-roll direct rolling or horizontal rolling.
[0022] Furthermore, after rolling the billet to obtain the titanium alloy wire, the process includes:
[0023] The titanium alloy wire is heat treated by controlling the temperature to be 100-500° C. lower than the phase transition point of the titanium alloy.
[0024] The present application also provides a free-cutting titanium alloy wire, which is produced by the above method.
[0025] Technical effects and advantages of this application:
[0026] 1. The present application selects free-cutting elements and designs the composition ratio of titanium alloy, then uses 2-3 VAR smelting to control the uniformity of the composition, controls the temperature between 150°C below the phase transition point of the titanium alloy and 200°C above the phase transition point of the titanium alloy to heat the ingot, performs drawing forging, controls the temperature between 100-150°C below the phase transition point of the titanium alloy to heat the rolled wire, draws the material at room temperature, and controls the temperature between 100-500°C below the phase transition point of the titanium alloy for heat treatment, so as to obtain a titanium alloy wire with a uniform structure and performance far exceeding the TA4 performance indicators.
[0027] 2. The tensile strength of the titanium alloy wire produced in this application is ≥770MPa, the yield strength is ≥700MPa, the elongation is ≥23%, the Brinell hardness is ≥270, and the cutting bending moment is 6% lower than that of TA4.
[0028] Other features and advantages of the present application will be described in the following description, and partly become apparent from the description, or be understood by practicing the present application. The purpose and other advantages of the present application can be realized and obtained by the structures indicated in the description, claims and drawings. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 This is a flow chart of a method for preparing a free-cutting titanium alloy wire according to the present application. DETAILED DESCRIPTION
[0030] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.
[0031] like Figure 1 As shown, the present application provides a method for preparing a free-cutting titanium alloy wire, comprising:
[0032] 1. Prepare titanium alloy electrodes.
[0033] Titanium alloy electrodes are prepared by using titanium sponge with Brinell hardness ≤ 110, Al particles, iron filings, TiFe32, titanium dioxide, Cu, and zirconium sponge. According to the mass percentage of each element in the titanium alloy electrode, the total content of Cu, Al, and Zr is 0.6-1.2%, the Fe content is 0.34-0.50%, the O content is 0.36-0.43%, the N content is ≤ 0.05%, the H content is ≤ 0.001%, the C content is ≤ 0.02%, and the Ti content is 98% ≤ ≤ 98.5%. The cutting performance of titanium alloy can be effectively improved by selecting the free-cutting elements in the titanium alloy and designing the composition ratio.
[0034] 2. Perform vacuum consumable melting on the titanium alloy electrode to obtain an ingot.
[0035] Vacuum consumable furnace smelting is currently the main method for preparing titanium alloy ingots, which has the advantages of fast smelting speed and the ability to produce large ingots.
[0036] This application optimizes and adjusts the smelting parameters according to the composition ratio of step 1. The details are as follows:
[0037] When using a crucible with an inner diameter of Φ570 for smelting, the arc starting current is 2-4kA, the melting current is 12-20kA, the melting voltage is 30-40V, the arc stabilization current is 5-10A, the feeding time is 15-30min, and the feeding end current is ≤7kA;
[0038] When using a crucible with an inner diameter of Φ660 for smelting, the arc starting current is 2-4kA, the melting current is 18-25kA, the melting voltage is 30-40V, the arc stabilization current is 8-12A, the feeding time is 15-30min, and the feeding end current is ≤7kA;
[0039] When using a crucible with an inner diameter of Φ750 for smelting, the arc starting current is 2-4kA, the melting current is 20-30kA, the melting voltage is 30-40V, the arc stabilization current is 8-18A, the feeding time is ≥120min, and the feeding end current is ≤4kA;
[0040] The melting times of vacuum consumable melting are 2-3 times, the melting current fluctuation is ≤1000A / min, the melting voltage fluctuation is ≤2V / min, and the arc stabilization current fluctuation is ≤1.5A / min.
[0041] By optimizing the smelting parameters, the uniformity of each component in the titanium alloy ingot can be effectively controlled.
[0042] 3. Forging the ingot to obtain a billet.
[0043] The ingot is heated at a temperature controlled between 150°C lower than the phase transformation point of the titanium alloy and 200°C higher than the phase transformation point of the titanium alloy, for example, 800°C-1070°C. The total heating time is calculated according to the cross-sectional thickness of the ingot. If the cross-sectional thickness of the ingot is ≥600mm, the total heating time is ≥480min. For every 1.0mm increase in the cross-sectional thickness of the ingot, the total heating time increases by 1.0-1.5min.
[0044] The heated ingot is subjected to drawing forging, with each pass deforming by 5%-50%;
[0045] The blank is polished and inspected to eliminate surface defects such as cracks and folds.
[0046] 4. Roll the billet to obtain titanium alloy wire.
[0047] The temperature is controlled to be 100-150°C lower than the phase transition point of the titanium alloy, and the billet is heated and rolled, for example, 810-870°C. The heating time is calculated according to the cross-sectional thickness of the billet. If the cross-sectional thickness of the billet is ≥140mm, the heating time is ≥140min. For every increase of 1.0-2.0mm in the cross-sectional thickness of the billet, the heating time is increased by 1min.
[0048] The heated billet is rolled into titanium alloy wire at room temperature by multi-roll direct rolling or horizontal rolling;
[0049] After the titanium alloy wire is obtained, the temperature is controlled to be 100-500° C. lower than the phase transition point of the titanium alloy to perform heat treatment on the titanium alloy wire, for example, 500-750° C.
[0050] Among them, the cross-sectional thickness is measured as a rectangular cross-section, and the length of the short side of the rectangle is the cross-sectional thickness.
[0051] This application designs the composition of the titanium alloy ingot and matches the appropriate forging and rolling process and heat treatment process based on the composition of the titanium alloy ingot, so that the tensile strength of the titanium alloy wire is ≥770MPa, the yield strength is ≥700MPa, the elongation is ≥23%, the Brinell hardness is ≥270, and the cutting bending moment is 6% lower than that of TA4.
[0052] The present application also provides a free-cutting titanium alloy wire, which is produced by the above method.
[0053] In order to better illustrate the present invention, the following examples are provided.
[0054] Example 1
[0055] S1. Prepare titanium alloy electrodes.
[0056] The electrode blocks were pressed using titanium sponge with a Brinell hardness of 100, Al particles, iron filings, TiFe32, titanium dioxide, Cu, and zirconium sponge as raw materials. The composition of the obtained titanium alloy electrode blocks is shown in Table 1.
[0057] Table 1 Composition of titanium alloy electrode block in Example 1
[0058]
[0059] S2. Perform vacuum consumable melting on the titanium alloy electrode to obtain an ingot.
[0060] The number of vacuum consumable melting is 3 times. During the melting process, the melting current fluctuation is controlled to be ≤1000A / min, the melting voltage fluctuation is ≤2V / min, and the arc stabilizing current fluctuation is ≤1.5A / min.
[0061] A titanium alloy ingot with a diameter of φ750 mm was obtained, and the phase transition point of the titanium alloy was detected to be 904°C by metallographic method.
[0062] S3. Forging the ingot to obtain a billet.
[0063] Three-stage heating is adopted in the electric heating furnace. The high-temperature deformation heating process is as follows: keep the temperature at 810℃ for 120min, heat it to 980±10℃ for 180min, and then keep it for 240min; complete two upsetting and drawing with a deformation amount of 45% in one fire, and draw the ingot to a cross-sectional length of 400mm*400mm. Return to the furnace to cool to 954℃ and keep it for 90min, then draw and forge it into a billet with a cross-sectional length of 200mm*200m.
[0064] The blank was milled and polished as a whole to eliminate surface cracks, and then colored and subjected to penetrant testing to obtain a blank with a cross-sectional side length of 190 mm*190 mm.
[0065] S4. Rolling the blank to obtain a titanium alloy wire.
[0066] The billet with a cross-sectional side length of 190mm*190m is heated at 820±10℃ in a walking beam heating furnace, and the holding time is calculated at 1.0-2.0mm / min. After heating, it is cooled to room temperature and rolled into φ8.5mm titanium alloy wire by multi-roll direct rolling or horizontal rolling.
[0067] The φ8.5 mm titanium alloy wire was heated at 650° C. for 2 h, then air-cooled to room temperature, and then heated at 500° C. for 5 hours to obtain a heat-treated titanium alloy wire.
[0068] Example 2
[0069] S1. Prepare titanium alloy electrodes.
[0070] The electrode block was pressed using titanium sponge with a Brinell hardness of 90, Al particles, iron filings, titanium dioxide, Cu, and zirconium sponge as raw materials. The composition of the obtained titanium alloy electrode block is shown in Table 2.
[0071] Table 2 Composition of titanium alloy electrode block in Example 2
[0072]
[0073] S2. Perform vacuum consumable melting on the titanium alloy electrode to obtain an ingot.
[0074] The number of vacuum consumable melting is 3 times. During the melting process, the melting current fluctuation is controlled to be ≤1000A / min, the melting voltage fluctuation is ≤2V / min, and the arc stabilizing current fluctuation is ≤1.5A / min.
[0075] A titanium alloy ingot with a diameter of φ750 mm was obtained, and the phase transition point of the titanium alloy was detected to be 918°C by metallographic method.
[0076] S3. Forging the ingot to obtain a billet.
[0077] Three-stage heating is adopted in the electric heating furnace. The high-temperature deformation heating process is to keep the temperature at 830℃ for 120min, heat it to 1000±10℃ for 180min, and then keep it for 240min. Two upsetting and drawing with a deformation amount of 45% are completed in one fire, and the ingot is drawn to a cross-sectional length of 400mm*400mm. After returning to the furnace to cool to 968℃ and keeping it for 90min, it is drawn and forged into a billet with a cross-sectional length of 200mm*200mm.
[0078] The blank is milled and polished as a whole, and after surface cracks are eliminated, it is colored and subjected to penetrant testing to obtain a blank with a cross-sectional side length of 190mm*190mm.
[0079] S4. Rolling the blank to obtain a titanium alloy wire.
[0080] The φ190mm billet is heated at 835±10℃ in a walking beam heating furnace, and the holding time is calculated as 1.0-2.0mm / min. After heating, it is cooled to room temperature and rolled into φ10mm titanium alloy wire by multi-roll direct rolling or horizontal rolling.
[0081] The φ10 mm titanium alloy wire was heated at 650° C. for 2 h, then air-cooled to room temperature, and then heated at 500° C. for 5 h to obtain a heat-treated titanium alloy wire.
[0082] Example 3
[0083] S1. Prepare titanium alloy electrodes.
[0084] The electrode blocks were pressed using titanium sponge with a Brinell hardness of 100, Al particles, iron filings, TiFe32, titanium dioxide, Cu, and zirconium sponge as raw materials. The composition of the obtained titanium alloy electrode blocks is shown in Table 3.
[0085] Table 3 Composition of titanium alloy electrode block in Example 3
[0086]
[0087] S2. Perform vacuum consumable melting on the titanium alloy electrode to obtain an ingot.
[0088] The number of melting times of vacuum consumable melting is 2 times. During the melting process, the melting current fluctuation is controlled to be ≤1000A / min, the melting voltage fluctuation is ≤2V / min, and the arc stabilizing current fluctuation is ≤1.5A / min.
[0089] A titanium alloy ingot with a diameter of φ660 mm was obtained, and the phase transition point of the titanium alloy was detected to be 971°C by metallographic method.
[0090] S3. Forging the ingot to obtain a billet.
[0091] Three-stage heating is adopted in the electric heating furnace. The high-temperature deformation heating process is as follows: keep the temperature at 830℃ for 120min, heat it to 1050±10℃ for 180min, and then keep it for 240min; complete two upsetting and drawing with a deformation amount of 5% in one fire, and draw the ingot to a cross-sectional length of 400mm*400mm. Return to the furnace to cool to 1010℃ and keep it for 90min, then draw and forge it into a billet with a cross-sectional length of 200mm*200mm.
[0092] The blank was milled and polished as a whole to eliminate surface cracks, and then colored and subjected to penetrant testing to obtain a blank with a cross-sectional side length of 190 mm*190 mm.
[0093] S4. Rolling the blank to obtain a titanium alloy wire.
[0094] The billet with a cross-sectional side length of 190mm*190mm is heated at 860±10℃ in a walking beam heating furnace, and the holding time is calculated as 1.0-2.0mm / min. After the heating is completed, it is cooled to room temperature and rolled into φ8.5mm titanium alloy wire by multi-roll direct rolling or horizontal rolling.
[0095] The φ8.5 mm titanium alloy wire was heated at 750° C. for 2 h, then air-cooled to room temperature, and then heated at 550° C. for 5 hours to obtain a heat-treated titanium alloy wire.
[0096] Example 4
[0097] S1. Prepare titanium alloy electrodes.
[0098] The electrode blocks were pressed using titanium sponge with a Brinell hardness of 90, Al particles, iron filings, titanium dioxide, Cu, and zirconium sponge as raw materials. The composition of the obtained titanium alloy electrode blocks is shown in Table 4.
[0099] Table 4 Composition of titanium alloy electrode block in Example 4
[0100]
[0101] S2. Perform vacuum consumable melting on the titanium alloy electrode to obtain an ingot.
[0102] The number of melting times of vacuum consumable melting is 2 times. During the melting process, the melting current fluctuation is controlled to be ≤1000A / min, the melting voltage fluctuation is ≤2V / min, and the arc stabilizing current fluctuation is ≤1.5A / min.
[0103] A titanium alloy ingot with a diameter of φ660 mm was obtained, and the phase transition point of the titanium alloy was detected to be 965.5°C by metallographic method.
[0104] S3. Forging the ingot to obtain a billet.
[0105] Three-stage heating is adopted in the electric heating furnace. The high-temperature deformation heating process is to keep the temperature at 850℃ for 120min, heat it to 1100℃ for 180min, and then keep it for 240min. Two upsetting and drawing with a deformation amount of 15% are completed in one fire, and the ingot is drawn to a cross-sectional length of 400mm*400mm. After returning to the furnace to cool to 1050℃ and keeping it for 90min, it is drawn and forged into a billet with a cross-sectional length of 200mm*200mm.
[0106] The blank is milled as a whole, ground to eliminate surface cracks, and then colored and subjected to penetrant testing to obtain a blank with a cross-sectional length of 190mm*190mm.
[0107] S4. Rolling the blank to obtain a titanium alloy wire.
[0108] The billet with a cross-sectional side length of 190mm*190mm is heated at 860±10℃ in a walking beam heating furnace, and the holding time is calculated at 1.0-2.0mm / min. After heating, it is cooled to room temperature and rolled into φ10mm titanium alloy wire by multi-roll direct rolling or horizontal rolling.
[0109] The φ10 mm titanium alloy wire was heated at 750°C for 2 hours, then air-cooled to room temperature, and then heated at 550°C for 5 hours to obtain a heat-treated titanium alloy wire.
[0110] The titanium alloy wires prepared in Examples 1-4 were subjected to room temperature mechanical property tests and bending moment tests. The test results of the room temperature mechanical property tests are shown in Table 6. The test was performed using a 62-degree 4mm tungsten steel end mill, and the bending moment value of the TA4 titanium alloy wire was used as the standard. The results of the bending moment test are shown in Table 7. The titanium alloy rods and wires prepared in the present application have a tensile strength of ≥770MPa, a yield strength of ≥700MPa, an elongation of ≥23%, a Brinell hardness (HB) of ≥270, and a cutting bending moment of 6% lower than that of the TA4 wire.
[0111] Table 6 Room temperature mechanical properties test results
[0112]
[0113] Table 7 Bending moment test results
[0114]
[0115] Finally, it should be noted that the above is only a preferred embodiment of the present application and is not intended to limit the present application. Although the present application has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.
Claims
1. A method for preparing a free-cutting titanium alloy wire, characterized in that: include: Preparation of titanium alloy electrodes; Performing vacuum consumable melting on the titanium alloy electrode to obtain an ingot; Forging the ingot to obtain a billet; Rolling the billet to obtain a titanium alloy wire; The method for preparing the titanium alloy electrode comprises: In the titanium alloy electrode, according to the mass percentage of each element, the total content of Cu, Al and Zr is 0.6-1.2%, the content of Fe is 0.34-0.50%, the content of O is 0.36-0.43%, the content of N is ≤0.05%, the content of H is ≤0.001%, the content of C is ≤0.02%, and the content of Ti is 98%≤≤98.5%.
2. The preparation method according to claim 1, characterized in that: The vacuum consumable melting process is repeated 2-3 times, the melting current fluctuation is ≤1000A / min, the melting voltage fluctuation is ≤2V / min, and the arc stabilizing current fluctuation is ≤1.5A / min.
3. The preparation method according to claim 1, characterized in that: The forging of the ingot comprises: The ingot is heated by controlling the temperature to be between 150° C. lower than the phase transformation point of the titanium alloy and 200° C. higher than the phase transformation point of the titanium alloy; The heated ingot is subjected to drawing forging, with each pass having a deformation amount of 5% to 50%.
4. The preparation method according to claim 3, characterized in that: The heating of the ingot comprises: the cross-sectional thickness of the ingot is ≥600 mm, and the total heating time is ≥480 min; The total heating time increases by 1.0-1.5 min for every 1.0 mm increase in the cross-sectional thickness of the ingot.
5. The preparation method according to claim 1, characterized in that: After forging the ingot to obtain a billet, the method comprises: The blank is ground and inspected to eliminate surface defects.
6. The preparation method according to claim 1, characterized in that: The step of rolling the blank comprises: The temperature is controlled to be 100-150° C. lower than the phase transformation point of the titanium alloy, and the billet is heated and rolled, wherein the cross-sectional thickness of the billet is ≥140 mm, and the heating time is ≥140 min. The heating time increases by 1 min for every increase of 1.0-2.0 mm in the cross-sectional thickness of the billet; The heated blank is rolled into titanium alloy wire at room temperature by multi-roller direct rolling or horizontal rolling.
7. The preparation method according to claim 1, characterized in that: After rolling the billet to obtain the titanium alloy wire, the method comprises: The titanium alloy wire is heat treated by controlling the temperature to be 100-500° C. lower than the phase transition point of the titanium alloy.
8. A free-cutting titanium alloy wire, characterized in that: The titanium alloy wire is prepared by the method according to any one of claims 1 to 7.