Preparation method and application of titanium alloy disc round wire resistant to high temperature of 650 DEG C

Abstract

The invention belongs to the technical field of titanium alloy machining, and relates to a preparation method and application of a titanium alloy disc round wire resistant to the high temperature of 650 DEG C. The method comprises the following steps: firstly, heating a prefabricated wire blank of which the chemical components and the microstructure are designed through combination of an induction heater and a tubular heating furnace, carrying out continuous rolling by utilizing a horizontally and vertically arranged continuous rolling mill, and obtaining a ten-square-section wire blank A of which the structure and the size meet requirements through hole pattern parameter design, induction heating and heat compensation between racks and control over pass deformation and accumulated deformation; then combined heating is conducted through an induction heater and a tubular heating furnace, hot drawing is conducted through a two-connection type roller die, and a round-section wire blank B is obtained; and heating by using an induction heater and a tubular heating furnace in a combined manner, controlling the heating temperature, peeling by using a peeling die to obtain a wire material with an accurate size, and finally polishing by using an abrasive belt polishing machine to obtain the target titanium alloy disc round wire material. The target titanium alloy disc round wire can be applied to high-temperature part fasteners of hypersonic aircrafts, aero-engines or airspace engines.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy processing, relates to a high-temperature titanium alloy coil wire, and specifically relates to a preparation method and application of a 650°C high-temperature resistant titanium alloy coil wire. Background Art

[0002] Hypersonic aircraft face severe performance challenges when operating in a thermal environment of 500℃~650℃. Not only must the strength of the fuselage be ensured, the aerodynamic shape be maintained, and the design be reusable and lightweight, but also the structural parts and fasteners of key parts such as the fuselage skin and aerodynamic leading edge are mostly made of high-temperature titanium alloys instead of high-temperature alloys to achieve weight reduction and high-temperature resistant design.

[0003] However, there is relatively little research on high-temperature resistant titanium alloy fasteners in China. The upper temperature limit of existing mature high-temperature titanium alloy wires generally does not exceed 600°C, which is difficult to meet the 650°C temperature requirement for high-temperature titanium alloy wires used in fasteners of new hypersonic aircraft. Therefore, the wires used for fasteners of new hypersonic aircraft can only be forced to use high-temperature alloys with a larger specific gravity. However, the thermal expansion coefficients of high-temperature alloys and titanium alloys differ by nearly one-fold, and there are also significant differences in thermal conductivity; under the action of thermal shock, the resulting thermal mismatch stress will seriously affect the service life of the fasteners, causing premature failure of the connection, posing a great threat to the service safety of the aircraft. Therefore, it is urgent to develop a high-temperature titanium alloy fastener wire with a temperature resistance level of 650°C.

[0004] There are two types of wire for fasteners: straight strips and coils. Compared with straight strips, coils have the advantages of good structural consistency, high material utilization, and high upsetting efficiency. At present, titanium alloy coils are usually prepared by drawing process. However, for high-temperature titanium alloys that can withstand 650°C, they have high high-temperature strength and low plasticity. If a large deformation is used for drawing, it is very easy to cause surface cracks, resulting in an increase in subsequent surface removal and a decrease in the wire yield. The traditional fixed die hot drawing method has the problems of high resistance to drawing deformation, easy scratching of the die, and easy cracking of the wire. In addition, the hot drawing deformation of high-temperature titanium alloys requires a higher heating temperature, while the traditional tubular furnace has a low heating efficiency and is difficult to meet the needs of efficient production.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a preparation method and application of a 650°C high-temperature titanium alloy coil wire, so as to solve the problems of drawing surface cracking, low yield and large mold loss in the existing high-temperature titanium alloy coil wire processing technology.

[0007] To achieve the above object, the present invention provides the following technical solutions: The method for preparing the 650°C high temperature resistant titanium alloy coil wire comprises the following steps: Step 1, rolling a wire billet A using a horizontal and vertical continuous rolling mill; Step 2, performing roller die hot drawing and rounding treatment on the wire blank A to obtain wire blank B; Step 3: hot stripping and polishing the wire blank B to obtain the target titanium alloy coil wire.

[0008] Specifically, the rolling process of step 1 is: The prefabricated wire billet is first heated by an induction heater combined with a tubular heating furnace, and then the heated prefabricated wire billet is continuously rolled by a horizontally arranged continuous rolling mill. The cumulative deformation during the continuous rolling process is 48.37%~77.56%; the induction heater is arranged between the frames of the continuous rolling mill to ensure the consistency of the final rolling temperature.

[0009] Furthermore, the induction heater adopts a high-frequency induction heater with a heating frequency of 20kHz~70kHz and a heating temperature of 850℃~950℃; the heating temperature of the tubular heating furnace is 900℃~1010℃; the temperature of each frame of the continuous rolling mill after rolling is 900℃~1010℃.

[0010] Specifically, the hole profile adopted by the continuous rolling mill is a homogeneous hole profile; preferably, the hole profile adopts a decagonal hole profile, the central angle α corresponding to each edge of the decagonal hole profile is 36°, the chamfer of the current hole profile is (1 / 4~1 / 3)d0, d0 is the diameter of the equivalent circular area of ​​the current hole profile after rolling, and the height H of the current hole profile can ensure that the cross-sectional area after rolling and the equivalent circular area are approximately equal (the area difference is less than or equal to 8%).

[0011] Furthermore, during the continuous rolling process, the deformation of the last pass is 5%~14%, and the deformation of each of the remaining passes is 9%~14%.

[0012] Specifically, the specific process of step 2 is: The obtained wire blank A is first subjected to induction heating, and then heated by a tubular heating furnace, and finally drawn by a two-continuous roller die (with an elliptical-circular hole type); wherein, Induction heating uses a high-frequency induction heater with a heating frequency of 20kHz~70kHz, an induction heating temperature of 850℃~910℃, and a tubular heating furnace with a heating temperature of 950℃~1010℃; The deformation of the two-pass roller die drawing is 12.89%~19.56%, and the temperature after drawing is greater than or equal to 900℃.

[0013] Specifically, in step 3, before hot peeling the wire blank B, the wire blank B is heated by using an induction heater and a tubular heating furnace; wherein, The induction heater adopts a high-frequency induction heater, and the heating frequency of the high-frequency induction heater is 20kHz~70kHz, and the heating temperature is 840℃~900℃; the heating temperature of the tubular heating furnace is 900℃~960℃.

[0014] Furthermore, in step 3, a belt polisher is used for polishing to ensure that the surface roughness Ra≤1.6 μm.

[0015] Specifically, in terms of mass percentage, the composition of each element in the prefabricated wire blank is as follows: Al: 5.3%~6.5%, Mo: 0.3%~0.8%, Nb: 0.2%~0.7%, Sn: 3.0%~4.5%, Ta: 0.5%~3.0%, Zr: 3.2%~5.2%, W: 0.9%~2.4%, C: 0.03%~0.08%, Si: 0.2%~0.5%, Fe≤0.01%, H≤0.005%, N≤0.02, O: 0.06%~0.10%, and the rest are Ti and unavoidable impurities; the β transformation temperature of the alloy is 1030℃~1060℃. Among them, in order to improve the thermal stability and surface oxidation resistance of the alloy, the content of O element is precisely controlled (0.06%~0.10%); and the content of W element is 0.9%~2.4%. Increasing the content of W element can significantly increase the high-temperature yield strength and tensile strength of the alloy. At the same time, the total content of impurity elements such as Fe, Ni, Cr, V, Cu, H, and N is strictly controlled not to exceed 0.1% to improve creep resistance and durability.

[0016] In addition, the present invention also provides an application of a 650°C high-temperature resistant titanium alloy coil wire. The 650°C high-temperature resistant titanium alloy coil wire prepared by part or all of the preparation method described above is used in fasteners in high-temperature parts such as hypersonic aircraft, aircraft engines, and aerospace engines.

[0017] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects: 1) The present invention focuses on the preparation of high-temperature titanium alloy coil wire and the characteristics of microstructure control, and selects a horizontal and vertical continuous rolling mill to carry out wire billet rolling; the rolling temperature is effectively controlled by designing hole parameters, controlling the rolling heating temperature, controlling the rolling cumulative deformation, controlling the pass deformation, and adding induction heating. On the one hand, the control of the rolled microstructure is achieved, and on the other hand, the rolling crack problem caused by low rolling temperature and excessive deformation resistance is avoided; 2) The present invention adopts roller die hot drawing, which utilizes a deformation method combining drawing and rolling, thereby avoiding the problem of easy scratching of the die and cracking of the wire surface caused by the large deformation resistance of the high-temperature titanium alloy wire drawn by the traditional fixed die; 3) The present invention utilizes induction heating combined with tubular heating furnace heating (induction heating has high efficiency and tubular heating furnace has uniform heating), which not only improves the heating efficiency of high-temperature titanium alloy, but also achieves temperature uniformity, effectively reduces the thickness of the surface oxide layer and contamination layer introduced during the heating process, reduces the surface cracking tendency of the high-temperature titanium alloy wire due to the surface oxide layer, and improves the stripping efficiency of the high-temperature titanium alloy wire. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The drawings herein are incorporated into the specification and constitute a part of the specification, and together with the specification are used to explain the principle of the present invention. In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings required for use in the embodiments or the prior art description will be briefly introduced below.

[0019] Figure 1 A flow chart of a method for preparing a 650°C high temperature resistant titanium alloy coil wire provided by the present invention; Figure 2 A transverse organization diagram of the prefabricated wire blank provided by the present invention; Figure 3 A rolling pass diagram of a continuous rolling mill provided by the present invention; Figure 4 This is a physical picture of the wire blank A during the preparation process of the coiled wire material in Example 1 of the present invention; Figure 5 This is a physical picture of the wire blank B during the preparation process of the coiled wire in Example 1 of the present invention; Figure 6 This is a photo of the finished product after peeling during the preparation of the coiled wire material in Example 1 of the present invention; Figure 7 This is a transverse high-magnification microstructure diagram of the target titanium alloy disc wire prepared in Example 1 of the present invention; Figure 8 This is a transverse high-magnification microstructure diagram of the target titanium alloy disc wire prepared in Example 2 of the present invention; Fig. 9 This is a transverse high-magnification microstructure diagram of the target titanium alloy disc wire obtained in Example 3 of the present invention. Fig.10 This is a high-magnification microstructure diagram of the coiled wire obtained in Example 1 of the present invention after solution aging heat treatment; Fig.11 This is a high-magnification microstructure diagram of the coiled wire obtained in Example 2 of the present invention after solution aging heat treatment; Fig.12This is a high-magnification microstructure diagram of the coiled wire obtained in Example 3 of the present invention after solution aging heat treatment. DETAILED DESCRIPTION

[0020] Here, exemplary embodiments will be described in detail, and the embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Instead, they are only examples consistent with some aspects of the present invention described in detail in the appended claims.

[0021] See also Figure 1 This embodiment provides a method for preparing a 650°C high temperature resistant titanium alloy coil wire, which specifically comprises the following steps: Step 1: Use a horizontal and vertical continuous rolling mill to roll the prefabricated wire billet to obtain wire billet A: The prefabricated wire blank is a coiled wire blank obtained by designing the chemical composition and microstructure; the elements in the prefabricated wire blank are as follows by mass percentage: Al: 5.3%~6.5%, Mo: 0.3%~0.8%, Nb: 0.2%~0.7%, Sn: 3.0%~4.5%, Ta: 0.5%~3.0%, Zr: 3.2%~5.2%, W: 0.9%~2.4%, C: 0.03~0.08%, Si: 0.2%~0.5%, Fe≤0.01%, H≤0.005%, N≤0.02, O: 0.06%~0.10%, and the rest are Ti and unavoidable impurities; its transverse structure is a uniform and fine α+β structure, see for details Figure 2 ; Furthermore, the 650°C high temperature resistant titanium alloy provided in this embodiment has a β transformation temperature of 1030°C to 1060°C, and a uniform and fine α+β structure in the transverse structure. The prefabricated wire blank used for rolling is heated by a high-frequency induction heater with a heating frequency of 20kHz to 70kHz and a temperature of 850°C to 950°C; after induction heating, it is uniformly heated by a tubular heating furnace with a heating temperature of 900°C to 1010°C, and then the heated prefabricated wire blank is hot-rolled by a hot rolling mill with a ten-square hole arrangement, see Figure 3 . Among them, the central angle α corresponding to each hole edge is 36°, the hole chamfer is (1 / 4~1 / 3)d0, d0 is the diameter of the equivalent circular area of ​​the hole after rolling, and the hole height H should ensure that the cross-sectional area after rolling is approximately equal to the equivalent circular area (the area difference does not exceed 8%). Induction heaters are arranged between the hot rolling stands. The rolling speed and induction heating temperature are used to control the temperature of each stand after rolling to between 900℃~1010℃. During the continuous rolling process, the deformation of the last pass is 5%~14%, and the deformation of each of the remaining passes is 9%~14%. The cumulative deformation of hot rolling is 48.37%~77.56%, and a wire billet with a square cross section is obtained after rolling.

[0022] Step 2: Perform roller die hot drawing and rounding treatment on the wire blank A to obtain wire blank B: The wire blank A with a square cross section obtained in step 1 is first heated with a high-frequency induction heater with a heating frequency of 20kHZ~70kHZ and a heating temperature of 850℃~910℃; after induction heating, it is evenly heated with a tubular heating furnace with a tubular heating temperature of 950℃~1010℃; finally, a two-stage roller die with an elliptical-circular hole shape is used for drawing, the deformation per pass is 12.89%~19.56%, and the temperature after drawing is greater than or equal to 900℃.

[0023] Step 3: hot stripping and polishing the wire blank B to obtain the target titanium alloy coil wire: The wire blank B is heated by a high-frequency induction heater, the heating frequency is 20kHz~70kHz, the heating temperature is 840℃~900℃, and after induction heating, it is heated by a tubular heating furnace, the heating temperature of the tubular heating furnace is 900℃~960℃, and the wire blank is peeled by a peeling die, and then polished by a belt polisher, and the surface roughness Ra≤1.6μm; Through the above three steps, a 650°C high-temperature resistant titanium alloy coil wire can be prepared whose surface, structure, room temperature performance and high temperature performance all meet the requirements.

[0024] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. Example 1 (Φ8.5 mm wire)

[0025] This embodiment provides a method for preparing a 650° C. high temperature resistant titanium alloy coil wire, which specifically comprises the following steps: Step 1: Use a horizontal and vertical continuous rolling mill to roll the prefabricated wire billet to obtain wire billet A: The prefabricated wire blank is a coiled wire blank obtained by designing the chemical composition and microstructure; the composition of each element in the prefabricated wire blank is as follows by mass percentage: Al: 5.3%, Mo: 0.3%, Nb: 0.7%, Sn: 4.5%, Ta: 0.5%, Zr: 4.0%, W: 2.4%, C: 0.03-0.05%, Si: 0.20-0.25%, Fe≤0.01%, H≤0.005%, N≤0.02, O: 0.10%, and the rest is Ti and unavoidable impurities; Furthermore, the prefabricated wire blank (Φ13.5 mm) used for rolling in this embodiment is heated by a high-frequency induction heater, the heating frequency is 20kHz~70kHz, and the heating temperature is 850°C; after induction heating, it is evenly heated by a tubular heating furnace, and the heating temperature is 900°C. The heated prefabricated wire blank is placed on a horizontally arranged hot rolling stand, and hot rolling is performed using a ten-square pass. Among them, the center angle α corresponding to each pass edge is 36°, the pass chamfer is 1 / 3d0, d0 is the diameter of the equivalent circular area after the pass is rolled, and the pass height H should ensure that the cross-sectional area after rolling is approximately equal to the equivalent circular area (the area difference does not exceed 7%). Induction heaters are arranged between the hot rolling stands. The rolling speed and induction heating temperature are used to control the temperature of each stand after rolling to be between 900℃ and 950℃. The deformation of each pass (excluding the deformation of the last pass) is controlled within the range of 9% to 14%. The deformation of the last pass of continuous rolling is 5%. The cumulative deformation during the hot rolling process is 48.37%. After rolling, a wire billet A with a square cross-section (equivalent circle Φ9.7mm) is obtained.

[0026] Step 2: Perform roller die hot drawing and rounding treatment on the wire blank A to obtain wire blank B: The wire blank A with a square cross-section obtained in step 1 is first heated with a high-frequency induction heater with a heating frequency of 20kHZ~70kHZ and a heating temperature of 850°C; after induction heating, it is evenly heated with a tubular heating furnace with a tubular heating temperature of 950°C; finally, a two-stage roller die with an elliptical-circular hole shape is used for drawing to obtain a wire blank B with a diameter of Φ8.7mm, a deformation of 19.56%, and a temperature greater than or equal to 900°C after drawing.

[0027] Step 3: hot stripping and polishing the wire blank B to obtain the target titanium alloy coil wire: The wire blank B is heated by a high-frequency induction heater with a heating frequency of 20kHz~70kHz and a heating temperature of 840℃. After induction heating, it is heated by a tubular heating furnace with a heating temperature of 900℃. It is stripped to Φ8.5mm with a stripping die and polished with a belt polisher after stripping, with a surface roughness Ra≤1.6μm. Example 2 (Φ5.0 mm wire)

[0028] This embodiment provides a method for preparing a 650° C. high temperature resistant titanium alloy coil wire, which specifically comprises the following steps: Step 1: Use a horizontal and vertical continuous rolling mill to roll the prefabricated wire billet to obtain wire billet A: The prefabricated wire blank is a coiled wire blank obtained by designing the chemical composition and microstructure; the composition of each element in the prefabricated wire blank is as follows by mass percentage: Al: 6.0%, Mo: 0.8%, Nb: 0.2%, Sn: 4.0%, Ta: 1.5%, Zr: 3.2%, W: 1.8%, C: 0.06-0.08%, Si: 0.30-0.35%, Fe≤0.01%, H≤0.005%, N≤0.02, O: 0.08%, and the rest is Ti and unavoidable impurities; Furthermore, the prefabricated wire blank (Φ10 mm) used for rolling in this embodiment is heated by a high-frequency induction heater, the heating frequency is 20kHz~70kHz, and the temperature of the induction heater is 890°C; after induction heating, it is evenly heated by a tubular heating furnace, the heating temperature is 950°C, and the heated prefabricated wire blank is placed on a horizontally arranged hot rolling mill stand, and hot rolling is performed using a ten-square pass. Among them, the central angle α corresponding to each pass edge is 36°, the pass chamfer is 1 / 3d0, d0 is the diameter of the equivalent circular area of ​​the pass after rolling, and the pass height H should ensure that the cross-sectional area after rolling is approximately equal to the equivalent circular area (the area difference does not exceed 6%). Induction heaters are arranged between the hot rolling stands. The rolling speed and induction heating temperature are used to control the temperature of each stand after rolling to be between 950℃ and 980℃. The deformation of each pass (excluding the deformation of the last pass) is controlled within the range of 9% to 14%. The deformation of the last pass of continuous rolling is 7%, and the cumulative deformation of hot rolling is 67.51%. After rolling, a wire billet A with a square cross-section (equivalent circle Φ5.7mm) is obtained.

[0029] Step 2: Perform roller die hot drawing and rounding treatment on the wire blank A to obtain wire blank B: The wire blank A with a square cross section obtained in step 1 is first heated with a high-frequency induction heater with a frequency of 20kHZ~70kHZ and an induction heating temperature of 890°C; after induction heating, it is evenly heated with a tubular heating furnace with a tubular heating temperature of 990°C; finally, a two-stage roller die with an elliptical-circular hole shape is used for drawing to obtain a Φ5.2mm wire blank B with a deformation of 16.77%, and a temperature greater than or equal to 900°C after drawing.

[0030] Step 3: hot stripping and polishing the wire blank B to obtain the target titanium alloy coil wire: The wire blank B is heated by a high-frequency induction heater with a frequency of 20kHz~70kHz and an induction heating temperature of 880°C. After induction heating, it is heated by a tubular heating furnace with a heating temperature of 940°C. It is stripped to Φ5.0mm by a stripping die and polished by a belt polisher after stripping, with a surface roughness Ra≤1.6μm. Example 3 (Φ4.0 mm wire)

[0031] This embodiment provides a method for preparing a 650° C. high temperature resistant titanium alloy coil wire, which specifically comprises the following steps:

[0032] Step 1: Use a horizontal and vertical continuous rolling mill to roll the prefabricated wire billet to obtain wire billet A: The prefabricated wire blank is a coiled wire blank obtained by designing the chemical composition and microstructure; the composition of each element in the prefabricated wire blank is as follows by mass percentage: Al: 6.5%, Mo: 0.5%, Nb: 0.5%, Sn: 3.0%, Ta: 3.0%, Zr: 5.2%, W: 0.9%, C: 0.05-0.07%, Si: 0.45-0.5%, Fe≤0.01%, H≤0.005%, N≤0.02, O: 0.06%, and the rest is Ti and unavoidable impurities; Furthermore, the prefabricated wire blank (Φ9.5 mm) used for rolling in this embodiment is heated by a high-frequency induction heater, the heating frequency is 20kHz~70kHz, and the temperature of the induction heater is 950°C; after induction heating, it is evenly heated by a tubular heating furnace, the heating temperature is 1010°C, and the heated prefabricated wire blank is placed on a horizontal hot rolling stand, and hot rolling is performed using a ten-square pass. Among them, the center angle α corresponding to each pass edge is 36°, the pass chamfer is 1 / 4d0, d0 is the diameter of the equivalent circular area after the pass is rolled, and the pass height H should ensure that the cross-sectional area after rolling is approximately equal to the equivalent circular area (the area difference does not exceed 5%). Induction heaters are arranged between the stands of the hot rolling mill. The temperature of each stand after rolling is between 980℃ and 1000℃. The deformation of each pass (excluding the deformation of the last pass) is controlled in the range of 9% to 14%. The deformation of the last pass of the continuous rolling is 10%. The cumulative deformation of the hot rolling is 77.56%. After rolling, a wire billet A with a square cross-section (equivalent circle Φ4.5mm) is obtained.

[0033] Step 2: Perform roller die hot drawing and rounding treatment on the wire blank A to obtain wire blank B: The wire blank A with a square cross-section obtained in step 1 is first heated with a high-frequency induction heater with a frequency of 20kHZ~70kHZ and an induction heating temperature of 910°C; after induction heating, it is evenly heated with a tubular heating furnace with a tubular heating temperature of 1010°C; finally, a two-stage roller die with an elliptical-circular hole shape is used for drawing to obtain a wire blank B with a diameter of Φ4.2mm, a deformation per pass of 12.89%, and a temperature after drawing greater than or equal to 900°C.

[0034] Step 3: hot stripping and polishing the wire blank B to obtain the target titanium alloy coil wire: The wire blank B is heated by a high-frequency induction heater with a frequency of 20kHz~70kHz and an induction heating temperature of 900°C. After induction heating, it is heated by a tubular heating furnace with a heating temperature of 960°C. It is stripped to Φ4.0mm by a stripping die and polished by a belt polisher after stripping, with a surface roughness Ra≤1.6μm.

[0035] Through analysis, it can be known that the rolled wire blank A, the drawn wire blank B, and the target titanium alloy coil wire obtained by peeling and polishing in the above Examples 1 to 3 are all efficient, stable, and crack-free, and can meet the preparation requirements of 650°C high-temperature resistant titanium alloy coil wire, and the process applicability is good. Here, taking Example 1 as an example, in the preparation process of coil wire of Example 1 of the present invention, the actual photos of wire blank A, wire blank B, and the finished product after peeling correspond to Figure 4 , Figure 5 , Figure 6 shown.

[0036] In order to further verify whether the internal structure and performance of the 650°C high temperature resistant titanium alloy wire prepared in Examples 1 to 3 above meet the use requirements of high temperature titanium alloys, samples were cut from Φ8.5mm, Φ5.0mm, and Φ4.0mm wires, respectively, and the room temperature and high temperature properties of the corresponding wires were tested: ① Cut samples of Φ8.5mm wire and test their room temperature and high temperature properties. After solution aging treatment, the test results are as follows: the room temperature tensile strength is 1120MPa~1185MPa, the yield strength is 1022MPa~1049MPa, the elongation is 9.0%~16.5%, the cross-sectional shrinkage is 16%~30%, and the shear strength is 652MPa~694MPa. At a high temperature of 650℃, the tensile strength is 630MPa~675MPa, the yield strength is 508MPa~542MPa, the elongation is 23.0%~28.5%, and the cross-sectional shrinkage is 26%~48%. The residual strain measured at 650℃, 100MPa, and 100h was 0.137%~0.187%; there was no fracture at 650℃, 200MPa, and more than 101h. After heat exposure at 650℃, the room temperature elongation was 5.7%~8.3%, and the area reduction was 7%~16%.

[0037] ② Cut samples of Φ5.0mm wire and test their room temperature and high temperature properties. After solution aging treatment, the test results are as follows: the room temperature tensile strength is 1130MPa~1192MPa, the yield strength is 1019MPa~1055MPa, the elongation after fracture is 9.5%~18.5%, the cross-sectional shrinkage is 23%~36%, and the shear strength is 666MPa~704MPa. At a high temperature of 650℃, the tensile strength is 633MPa~684MPa, the yield strength is 515MPa~548MPa, the elongation after fracture is 23.2%~32.5%, and the cross-sectional shrinkage is 28%~45%. The residual strain measured at 650℃, 100MPa, and 100h is 0.148%~0.192%; at 650℃, 200MPa, and more than 101h, it did not break.

[0038] ③ Samples were cut from Φ4.0mm wire to test its room temperature and high temperature properties. After solution aging treatment, the test results are as follows: the room temperature tensile strength is 1135MPa~1196MPa, the yield strength is 1033MPa~1059MPa, the elongation after fracture is 9.0%~17.5%, the cross-sectional shrinkage is 18%~32%, and the shear strength is 663MPa~695MPa. At a high temperature of 650℃, the tensile strength is 642MPa~687MPa, the yield strength is 512MPa~563MPa, the elongation after fracture is 25.7%~33.5%, and the cross-sectional shrinkage is 32%~56%. The residual strain measured at 650℃, 100MPa, and 100h is 0.143%~0.188%; at 650℃, 200MPa, and more than 101h, it did not break.

[0039] Figure 7~Figure 9 The transverse high-magnification structures of the 650°C high-temperature resistant titanium alloy wires obtained in Example 1, Example 2, and Example 3 of the present invention respectively correspond to the following; Figure 10~Figure 12 The high-magnification structures of the coiled wires obtained in Example 1, Example 2, and Example 3 of the present invention after solution aging heat treatment are shown. Figure 7 to Figure 12 It can be seen that the target titanium alloy disc wire prepared by the preparation method provided by the present invention has fine and evenly distributed grains, evenly distributed phases, and no obvious defects.

[0040] In summary, the applicant combined the above tests and analyzed the test results to find that the 650°C high-temperature resistant titanium alloy coil wire prepared by the present invention has good room temperature performance and high temperature performance, can meet the preparation requirements of 650°C high-temperature resistant titanium alloy fasteners, and has good application prospects.

[0041] The above description is only a specific embodiment of the present invention, so that those skilled in the art can understand or implement the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention.

[0042] It should be understood that the present invention is not limited to what has been described above and that various modifications and changes may be made without departing from its scope. The scope of the present invention is limited only by the appended claims.

Claims

1. A method for preparing a 650°C high temperature resistant titanium alloy coil wire, characterized in that: The following steps are involved: Step 1: rolling the prefabricated wire billet using a horizontal and vertical continuous rolling mill to obtain wire billet A; Step 2, performing roller die hot drawing and rounding treatment on the wire blank A to obtain wire blank B; Step 3: hot stripping and polishing the wire blank B to obtain the target titanium alloy coil wire.

2. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 1, characterized in that: The rolling process of step 1 is: The prefabricated wire billet is first heated by an induction heater combined with a tubular heating furnace, and then the heated prefabricated wire billet is continuously rolled by a horizontally arranged continuous rolling mill. The cumulative deformation during the continuous rolling process is 48.37%~77.56%; the induction heater is arranged between the frames of the continuous rolling mill.

3. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 2, characterized in that: The induction heater adopts a high-frequency induction heater, the heating frequency is 20kHz~70kHz, and the heating temperature is 850℃~950℃; the heating temperature of the tubular heating furnace is 900℃~1010℃.

4. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 2, characterized in that: The temperature of each continuous rolling mill frame after rolling is 900℃~1010℃.

5. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 2, characterized in that: During the continuous rolling process, the deformation of the last pass is 5%~14%, and the deformation of each of the remaining passes is 9%~14%.

6. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 1, characterized in that: The specific process of step 2 is: The obtained wire blank A is firstly subjected to induction heating, then heated by a tubular heating furnace, and finally drawn by a two-continuous roller die; wherein, Induction heating uses a high-frequency induction heater with a heating frequency of 20kHz~70kHz and a heating temperature of 850℃~910℃; the heating temperature of the tubular heating furnace is 950℃~1010℃; The deformation of the two-pass roller die drawing is 12.89%~19.56%, and the temperature after drawing is greater than or equal to 900℃.

7. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 1, characterized in that: In step 3, before hot peeling the wire blank B, the wire blank B is heated by using an induction heater and a tubular heating furnace; wherein, The induction heater adopts a high-frequency induction heater, and the heating frequency of the high-frequency induction heater is 20kHz~70kHz, and the heating temperature is 840℃~900℃; the heating temperature of the tubular heating furnace is 900℃~960℃.

8. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 1, characterized in that: In step 3, a belt polisher is used for polishing to ensure that the surface roughness Ra is ≤ 1.6 μm.

9. The method for preparing the 650°C high temperature resistant titanium alloy coil wire according to claim 1, characterized in that: In step 1, the composition of each element in the prefabricated wire blank is as follows, calculated by mass percentage: Al: 5.3%~6.5%, Mo: 0.3%~0.8%, Nb: 0.2%~0.7%, Sn: 3.0%~4.5%, Ta: 0.5%~3.0%, Zr: 3.2%~5.2%, W: 0.9%~2.4%, C: 0.03%~0.08%, Si: 0.2%~0.5%, Fe≤0.01%, H≤0.005%, N≤0.02, O: 0.06%~0.10%, and the rest is Ti and unavoidable impurities.

10. An application of a 650°C high temperature resistant titanium alloy coil wire, characterized in that: Application of 650°C high temperature resistant titanium alloy coil wire prepared by the preparation method according to any one of claims 1 to 9 in fasteners for hypersonic aircraft, aeroengines or aerospace engines.

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