Titanium alloy wire and preparation method thereof

Abstract

The invention discloses a titanium alloy wire and a preparation method thereof, and belongs to the technical field of titanium alloy processing. The preparation method of the titanium alloy wire comprises the following steps: preparing a titanium alloy electrode; smelting the titanium alloy electrode to obtain a cast ingot; forging the cast ingot to obtain a blank; rolling the blank to obtain a titanium alloy wire; the titanium alloy electrode comprises the following chemical components in percentage by mass: 0.1%-1.5% of Sn, Al and Si, 0.3%-0.4% of Fe, 0.25%-0.38% of O, less than or equal to 0.05% of N, less than or equal to 0.001% of H, less than or equal to 0.02% of C and 98%-99% of Ti. Through design of components of the titanium alloy cast ingot and matching of a heat treatment process, the tensile strength of the prepared titanium alloy wire is larger than or equal to 720 MPa, the yield strength is larger than or equal to 670 MPa, the ductility is larger than or equal to 22%, and the Brinell hardness is larger than or equal to 260.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy processing, and in particular to a titanium alloy wire and a preparation method thereof. Background Art

[0002] With the rapid development of 3C consumer electronics, new requirements have been put forward for the performance indicators and process costs of titanium and titanium alloy materials. However, since conventional processes focus on the comprehensive performance of titanium and titanium alloy products and do not make too many requirements on processing performance and process costs, the application of titanium and titanium alloys in the field of 3C consumer electronics has been restricted.

[0003] TA4, as a medium-strength and low-cost (relative to TC4 titanium alloy) titanium alloy, has been used in sports and leisure, digital products, and consumer electronics. However, its strength, hardness, and processing performance restrict its widespread application. Summary of the invention

[0004] The purpose of the present invention is to provide a titanium alloy wire and a preparation method thereof, so as to solve the technical problem that the titanium alloy in the prior art has poor processing performance when applied in the 3C field.

[0005] To achieve the above object, an embodiment of the present invention provides a method for preparing a titanium alloy wire, comprising the following steps:

[0006] Preparation of titanium alloy electrodes;

[0007] Melting the titanium alloy electrode to obtain an ingot;

[0008] Forging the ingot to obtain a billet;

[0009] Rolling the billet to obtain a titanium alloy wire;

[0010] The titanium alloy electrode includes the following chemical components in mass percentage: the total content of Sn, Al and Si is 0.1%-1.5%, the content of Fe is 0.3%-0.4%, the content of O is 0.25%-0.38%, 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%-99%.

[0011] One of the preferred schemes of the present invention is to melt the titanium alloy electrode to obtain an ingot, including: performing vacuum consumable melting on the titanium alloy electrode, the melting times are 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] One of the preferred solutions of the present invention is to forge the ingot to obtain a blank, comprising:

[0013] heating the ingot at a temperature of 150° C. below the phase transformation point of the titanium alloy to 100° C. above the phase transformation point of the titanium alloy;

[0014] The heated ingot is subjected to drawing forging.

[0015] One of the preferred schemes of the present invention is to heat the ingot at a temperature of 150°C below the phase transformation point of the titanium alloy to 100°C above the phase transformation point of the titanium alloy, including: calculating the total heating time based on the cross-sectional size of the ingot, and the total heating time increases by 1.2mm-1.5mm when the cross-sectional size increases by 1min.

[0016] One of the preferred solutions of the present invention is to perform stretching forging on the heated ingot, including: the deformation amount of each pass is 5%-50%.

[0017] According to one of the preferred solutions of the present invention, the blank is subjected to finishing, grinding and flaw detection before rolling.

[0018] One of the preferred schemes of the present invention is to roll the billet to obtain titanium alloy wire, including: heating the billet at a temperature between 150°C below the phase transformation point of the titanium alloy and 50°C above the phase transformation point of the titanium alloy, and rolling the heated billet by multi-roll direct rolling or horizontal rolling.

[0019] One of the preferred solutions of the present invention is to calculate the total heating time based on the cross-sectional size of the blank. When the cross-sectional size increases by 1.0 mm, the total heating time increases by 1.0 min to 2.0 min.

[0020] According to one of the preferred solutions of the present invention, after obtaining the titanium alloy wire, the titanium alloy wire is heat treated at a temperature of 100° C. to 380° C., which is lower than the phase transition point of the titanium alloy.

[0021] The invention also discloses a titanium alloy wire material, which is prepared by adopting the above preparation method.

[0022] In summary, the beneficial effects of the present invention are:

[0023] 1. The present invention selects strengthening elements and free-cutting elements of titanium alloy and designs the composition ratio, then adopts 2-3 times of VAR smelting to control the uniformity of the composition, heats the ingot at 150°C below the phase transition point of the titanium alloy and 100°C above the phase transition point of the titanium alloy, performs drawing forging, heats the rolled wire at 150°C below the phase transition point of the titanium alloy and 50°C above the phase transition point of the titanium alloy, draws the wire at room temperature, and performs heat treatment at 100°C-380°C below the phase transition point of the titanium alloy. The titanium alloy wire with uniform organization and performance far exceeding the TA4 performance index can be obtained. The whole process has strong operability and is easy to realize industrial production. The obtained titanium alloy wire can be widely used in the field of 3C consumer electronics.

[0024] 2. The present invention designs the composition of the titanium alloy ingot and matches the heat treatment process so that the tensile strength of the prepared titanium alloy wire is ≥720MPa, the yield strength is ≥670MPa, the elongation is ≥22%, and the Brinell hardness is ≥260.

[0025] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by implementing the present invention. The purpose and other advantages of the present invention can be described by the effects described in the description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of a method for preparing a titanium alloy wire of the present invention;

[0027] Figure 2 The grain structure diagram of the titanium alloy wire prepared in Example 1 of the present invention;

[0028] Figure 3 This is a grain structure diagram of the titanium alloy wire prepared in Example 2 of the present invention. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The endpoints and any values ​​of the ranges disclosed in the present invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0031] The present invention provides a method for preparing a titanium alloy wire, such as Figure 1 As shown, the following steps are included:

[0032] Step (1): preparing a titanium alloy electrode; specifically, using titanium sponge with HBW (Brinell hardness) ≤ 110, Al particles, iron filings, TiFe32, titanium dioxide, TiSn80, and AlSi11 to prepare the titanium alloy electrode, the titanium alloy electrode comprising the following chemical components in mass percentage: the total content of Sn, Al, and Si is 0.1%-1.5%, the content of Fe is 0.3%-0.4%, the content of O is 0.25%-0.38%, 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%-99%;

[0033] Step (2): melting the titanium alloy electrode to obtain an ingot; specifically, the titanium alloy electrode is melted in a vacuum consumable furnace, the melting times are 2-3 times, and the power parameters of the melting are performed according to Table 1. The parameters need to be adjusted in the normal melting stage, and the melting current fluctuation should be ≤1000A / min, the melting voltage fluctuation should be ≤2V / min, and the arc stabilizing current fluctuation should be ≤1.5A / min;

[0034] Table 1: Ingot melting process

[0035]

[0036] Step (3): forging the ingot to obtain a blank; specifically, comprising:

[0037] Step (301): heating the ingot at a temperature of 150°C below the phase transition point of the titanium alloy and 100°C above the phase transition point of the titanium alloy; at a temperature of 150°C below the phase transition point of the titanium alloy and 100°C above the phase transition point of the titanium alloy, such as 820°C-1050°C, the total heating time is calculated according to the cross-sectional size of the ingot, the total heating time increases by 1.2min-1.5min as the cross-sectional size increases by 1mm, and the shortest total heating time is ≥480min, wherein the high temperature section insulation time accounts for 50-70%;

[0038] Step (302): performing stretch forging on the heated ingot; specifically, performing stretch forging on the heated ingot, with each pass of deformation being 5%-50%, and performing finishing, grinding, and flaw detection on the blank to eliminate defects such as surface cracks and folds;

[0039] Step (4): rolling the billet to obtain a titanium alloy wire; specifically, heating the billet at a temperature between 150°C below the phase transition point of the titanium alloy and 50°C above the phase transition point of the titanium alloy, such as 820°C-1020°C, and calculating the total heating time according to the cross-sectional size of the billet. The total heating time increases by 1.0min-2.0min when the cross-sectional size increases by 1.0mm, and the shortest total heating time is ≥120min, of which the insulation time accounts for ≥80%; rolling the heated billet by multi-roll direct rolling or horizontal rolling to obtain a titanium alloy wire, and after obtaining the titanium alloy wire, heat treating the titanium alloy wire at a temperature of 100°C-380°C below the phase transition point of the titanium alloy, such as 500°C-800°C.

[0040] The invention also discloses a titanium alloy wire material, which is prepared by adopting the above preparation method.

[0041] By designing the composition of the titanium alloy ingot and matching the heat treatment process, the present invention can make the titanium alloy wire have a tensile strength of ≥720MPa, a yield strength of ≥670MPa, an elongation of ≥22%, and a Brinell hardness of ≥260; the titanium alloy wire prepared by the present invention has performance far exceeding the TA4 performance index, has uniform structure and strong operability, is easy to realize industrial production, and can be widely used in the 3C consumer electronics field.

[0042] In order to better illustrate the present invention, the following examples are provided.

[0043] Example 1

[0044] Production specification Φ8.5mm wire

[0045] (1) Preparation of titanium alloy electrodes:

[0046] Sponge titanium with HBW (Brinell hardness) 110, Al particles, TiFe32, titanium dioxide, TiSn80, AlSi11, etc. are used as raw materials to prepare and press electrode blocks, and the composition of the obtained titanium alloy electrode is shown in Table 2;

[0047] Table 2: Composition of titanium alloy electrode in Example 1

[0048]

[0049] Where SUM is the sum of Sn, Al and Si elements;

[0050] (2) Smelting the titanium alloy electrode to obtain an ingot:

[0051] After vacuum plasma welding, two VAR (consumable electrode melting furnace) smeltings were carried out to produce titanium ingots with a diameter of Φ660mm. The phase change point was detected by metallographic method to be 971.5℃;

[0052] (3) Forging the ingot to obtain a billet:

[0053] ① In the electric heating furnace, three-stage heating is adopted. The high-temperature deformation heating process is kept at 850±10℃ for 120min, heated to 1020±10℃ for 180min, and then kept for 300min; two upsettings with a deformation amount of 45% are completed in one fire, and the titanium ingot is drawn into a rectangle of 400*400*Lmm, returned to the furnace to cool to 960±10℃ and kept for 90min, and then drawn and forged into a billet with a length of 200*200*4500-6000mm;

[0054] ② Mill and polish the entire blank, eliminate surface cracks, and then perform coloring and penetration testing;

[0055] (4) Rolling the billet to obtain a titanium alloy wire:

[0056] The billet with a size of 190*190*4500-6000mm is heated at 860±10°C in a walking beam heating furnace, the holding time is calculated at 1.0-2.0mm / min, and the billet is rolled into a titanium alloy wire with a diameter of Φ8.5mm by multi-roll direct rolling or horizontal rolling;

[0057] The Φ8.5mm titanium alloy wire was kept at 700±10℃ for 2h, then air-cooled to room temperature, and then kept at 500±10℃ for 5h to obtain the heat-treated titanium alloy wire. The microstructure and performance of the heat-treated titanium alloy wire were tested. The detected grain structure is as follows: Figure 2 shown.

[0058] It can be seen from Example 1 that when producing wires with a specification of Φ8.5mm, 2 VAR smelting is adopted according to the impurity elements introduced into the raw materials such as 1.15% of the sum of Sn, Al and Si elements, 0.34% of Fe, 0.36% of O, C / H / N, etc.; the ingot is first heated at 150°C below the phase transition point of the titanium alloy and 100°C above the phase transition point of the titanium alloy, and the drawing forging is carried out, and the deformation amount per pass is 5%-50%, and then the billet is finely ground and inspected to eliminate defects such as surface cracks and folds; then, it is heated at 150°C below the phase transition point of the titanium alloy and 50°C above the phase transition point of the titanium alloy, and the billet of 190*190*4500-6000m is rolled into a wire of Φ8.5mm by a multi-roll direct rolling method; the wire of Φ8.5mm is annealed and the performance is tested, and the tensile strength is ≥720MPa, the yield strength is ≥670MPa, the elongation is ≥22%, and the Brinell hardness is ≥260.

[0059] Example 2

[0060] Production specification Φ12mm wire

[0061] (1) Preparation of titanium alloy electrodes:

[0062] Sponge titanium with HBW (Brinell hardness) of 110, Al particles, iron filings, titanium dioxide, TiSn80, AlSi11, etc. are used as raw materials to prepare and press electrode blocks, and the composition of the obtained titanium alloy electrode is shown in Table 3;

[0063] Table 3: Composition of titanium alloy electrode in Example 3

[0064]

[0065] Where SUM is the sum of Sn, Al and Si elements;

[0066] (2) Smelting the titanium alloy electrode to obtain an ingot:

[0067] After vacuum plasma welding, two VAR (consumable electrode melting furnace) smeltings were carried out to produce titanium ingots with a diameter of Φ660mm. The phase transition point was 968.5℃ detected by metallographic method.

[0068] (3) Forging the ingot to obtain a billet:

[0069] ① In the electric heating furnace, three-stage heating is adopted. The high-temperature deformation heating process is kept at 820±10℃ for 120min, heated to 1050±10℃ for 180min, and then kept for 300min; two upsetting and drawing with a deformation amount of 45% are completed in one fire, and a rectangle of 400*400*Lmm is forged. After returning to the furnace to cool to 960±10℃ and keeping for 90min, the billet is drawn and forged into 200*200*4500-6000mm;

[0070] ② Mill and grind the entire blank, eliminate surface cracks, and then perform coloring and penetration testing;

[0071] (4) Rolling the billet to obtain a titanium alloy wire:

[0072] The billet with a size of 190*190*4500-6000mm is heated at 840±10°C in a walking beam heating furnace, the holding time is calculated at 1.0-2.0mm / min, and the billet is rolled into a titanium alloy wire with a diameter of Φ12mm by multi-roll direct rolling or horizontal rolling;

[0073] The Φ12mm titanium alloy wire was kept at 650±10℃ for 2h, then air-cooled to room temperature, and then kept at 500±10℃ for 5h to obtain the heat-treated titanium alloy wire. The microstructure and performance of the heat-treated titanium alloy wire were tested. The detected grain structure is as follows: Figure 3 shown.

[0074] It can be seen from Example 2 that when producing wires with a specification of Φ12mm, the ingredients are prepared according to the sum of Sn, Al and Si elements of 1.02%, Fe of 0.36%, and O of 0.38%, C / H / N and other impurity elements introduced by the raw materials, and two VAR smeltings are adopted; the ingot is first heated at 150°C below the phase transition point of the titanium alloy and 100°C above the phase transition point of the titanium alloy, and the drawing forging is carried out, and the deformation amount per pass is 5%-50%, and then the billet is finely ground and inspected to eliminate defects such as surface cracks and folds; then the billet is heated at 150°C below the phase transition point of the titanium alloy and 50°C above the phase transition point of the titanium alloy, and the billet of 190*190*4500-6000m is rolled into a wire of Φ12mm by a multi-roll direct rolling method; the wire of Φ12mm is annealed, and the performance is tested, and the tensile strength is ≥740MPa, the yield strength is ≥670MPa, the elongation is ≥23%, and the Brinell hardness is ≥265.

[0075] The performance of the titanium alloy wires prepared in Example 1 and Example 2 was tested, and the test results are shown in Table 4;

[0076] Table 4: Properties of titanium alloy wires prepared in Example 1 and Example 2

[0077]

[0078] It can be seen from Table 4 that the wire produced by the present invention has a strength and toughness that is better than the TA4 wire technical standard requirements of GB / T2965-2007, and has medium strength and toughness, and can be widely used in 3C field products.

[0079] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering and technical personnel in the field should all fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing a titanium alloy wire, characterized in that: The following steps are involved: Preparation of titanium alloy electrodes; Melting 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 titanium alloy electrode comprises the following chemical components in mass percentage: the total content of Sn, Al and Si is 0.1%-1.5%, the content of Fe is 0.3%-0.4%, the content of O is 0.25%-0.38%, 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%-99%.

2. The method for preparing a titanium alloy wire according to claim 1, characterized in that: The titanium alloy electrode is melted to obtain an ingot, comprising: vacuum consumable melting of the titanium alloy electrode, the melting times are 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 method for preparing a titanium alloy wire according to claim 1, characterized in that: The method of forging the ingot to obtain a blank comprises: heating the ingot at a temperature of 150° C. below the phase transformation point of the titanium alloy to 100° C. above the phase transformation point of the titanium alloy; The heated ingot is subjected to drawing forging.

4. The method for preparing a titanium alloy wire according to claim 3, characterized in that: The heating of the ingot at a temperature of 150°C below the phase transition point of the titanium alloy to 100°C above the phase transition point of the titanium alloy includes: calculating the total heating time according to the cross-sectional size of the ingot, and the total heating time increases by 1.2mm-1.5mm when the cross-sectional size increases by 1min.

5. The method for preparing a titanium alloy wire according to claim 3, characterized in that: The stretching forging of the heated ingot includes: the deformation amount of each pass is 5%-50%.

6. The method for preparing a titanium alloy wire according to claim 1, characterized in that: Before rolling the billet, the billet is subjected to finishing, grinding and flaw detection.

7. The method for preparing a titanium alloy wire according to claim 1, characterized in that: The method of rolling the billet to obtain the titanium alloy wire comprises: heating the billet at a temperature between 150°C lower than the phase transition point of the titanium alloy and 50°C higher than the phase transition point of the titanium alloy, and rolling the heated billet by multi-roll direct rolling or horizontal rolling.

8. The method for preparing a titanium alloy wire according to claim 7, characterized in that: The total heating time is calculated based on the cross-sectional dimensions of the blank. If the cross-sectional dimensions increase by 1.0 mm, the total heating time will increase by 1.0 min to 2.0 min.

9. The method for preparing a titanium alloy wire according to claim 1, characterized in that: After the titanium alloy wire is obtained, the titanium alloy wire is heat treated at a temperature of 100° C. to 380° C., which is lower than the phase transition point of the titanium alloy.

10. A titanium alloy wire, characterized in that: The method is prepared by the method according to any one of claims 1 to 9.

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