Preparation method of high-performance titanium-zirconium alloy small-size rod for dental use

Abstract

The application discloses a preparation method of high-performance titanium-zirconium alloy small-specification rod for dentistry, and comprises the following steps: firstly, taking titanium-zirconium alloy cylindrical ingot with oxygen content less than 0.15% to perform hot forming isothermal forging; secondly, performing finish forging; thirdly, after warm rolling, performing cross rolling in square, circular, flat and flat hole type in turn and two-pass circular hole type rolling; fourthly, performing cold rotary forging; and fifthly, performing vacuum annealing. By limiting the oxygen content in the raw material ingot, combining with the isothermal forging, finish forging, warm rolling and cold rotary forging processes, the grain is fully refined, the raw material ingot is fully deformed, the rod organization uniformity and stability are improved, and therefore, the titanium-zirconium alloy small-specification rod with high purity, low oxygen content, high strength and plasticity and good matching property is obtained, and is suitable for the dentistry.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of titanium alloy material processing, and particularly relates to a preparation method of high-performance titanium-zirconium alloy small-specification rod for dentistry. BACKGROUND

[0002] Since the theory of self-bone combination was proposed, pure titanium and titanium alloy have been the first choice of materials for oral implants. Pure titanium has good biocompatibility, mechanical properties and corrosion resistance, and is an important material in the fields of dentistry, orthopedics, trauma and other medical devices, and is mainly used for oral implants, crowns, fixed bridges, denture supports and the like. In recent years, with the rapid development of the field of medical materials, in order to improve the safety and reliability of new dental instruments and prolong the service life, the design and development trend of medical materials is mainly aimed at better matching of higher strength and higher plasticity. At present, the strength and wear resistance of pure titanium used for implants are poor, and most of them need to be surface treated before clinical application. In view of this, a new type of titanium-zirconium alloy with high strength and high wear resistance has been developed. However, the strength and plasticity of the titanium-zirconium alloy rod obtained by the conventional hot working process cannot achieve good mechanical matching and quality stability, and most of them need to be oxygenated, so that the impurity oxygen content is increased to a relatively high value of 0.3%, so that the tensile strength of the alloy reaches 864 MPa, the yield strength reaches 735 MPa, and the Vickers hardness is 267. However, for the cleanliness and safety of oral implant instruments for the human body, the oxygenation method will increase the internal crystal defects of the material, thereby causing the risk of instantaneous fracture of the instrument. Therefore, hospitals and medical instrument companies generally require that the oxygen content of titanium-zirconium processing materials be below 0.15%. For such titanium-zirconium alloys with small impurity content, it is difficult to obtain high strength and high plasticity of dental titanium-zirconium rods according to the general conventional processing and preparation method. SUMMARY

[0003] The technical problem to be solved by the present application is to provide a preparation method of high-performance titanium-zirconium alloy small-specification rod for dentistry in view of the above-mentioned deficiencies of the prior art. The method limits the oxygen content in the raw material ingot, combines isothermal forging, precision forging and warm rolling, cold spinning process, fully refines the grains, promotes the deformation of the raw material ingot, and improves the uniformity and stability of the rod structure, so as to obtain a titanium-zirconium alloy small-specification rod with high purity, low oxygen content, high strength and plasticity, and good matching, thereby solving the problem that the titanium-zirconium alloy small-specification rod for dentistry cannot have low oxygen content and high strength and plasticity at the same time.

[0004] To solve the above technical problems, the technical scheme adopted by the present application is as follows: a preparation method of high-performance titanium-zirconium alloy small-specification rod for dentistry, characterized in that the method comprises the following steps:

[0005] Step one, the titanium-zirconium alloy cylindrical ingot with oxygen mass content less than 0.15% is placed on a hot forming equipment to perform hot forming isothermal forging, and is pressed along longitudinal Y axis, transverse X axis and transverse Z axis of the titanium-zirconium alloy cylindrical ingot in sequence according to three-dimensional coordinate system, and after the blanking, water cooling is performed to obtain a square bar blank;

[0006] Step two, the square bar blank obtained in step one is placed on a precision forging machine to perform precision forging, and a round forging bar blank is obtained;

[0007] Step three, the round forging bar blank obtained in step two is subjected to warm rolling by adopting a cross-bar rolling mill, and then is subjected to square, round, flat, flat pass cycle cross rolling, and then is subjected to two-pass round pass rolling, and after air cooling, a round rolling bar is obtained;

[0008] Step four, the round rolling bar obtained in step three is subjected to cold rotary forging by adopting a precision rotary forging machine, and a processing state small-size bar material is obtained;

[0009] Step five, the processing state small-size bar material obtained in step four is subjected to vacuum annealing, and a high-performance titanium-zirconium alloy small-size bar material for dentistry is obtained; the high-performance titanium-zirconium alloy small-size bar material for dentistry has A1 grade microstructure, and the mechanical properties are as follows: tensile strength 767 MPa-877 MPa, yield strength 638 MPa-782 MPa, elongation 15%-20%, and microhardness HV 254-268.

[0010] The titanium-zirconium alloy ingot is first converted into a round forging bar blank by hot forming isothermal forging and precision forging, and the grains are preliminarily refined, then large deformation is realized by warm rolling, and high content of martensite is generated, then further large deformation is realized by cold rotary forging, secondary martensite is generated in the large volume of martensite in the structure, and a large number of dislocation cell structures are generated around the primary martensite, nanometer and submicron size (~1 μm) grains are obtained, and the strength of the bar material is improved; then, by vacuum annealing, while ensuring that only the dislocation cells and other crystal defects in the structure are reduced, the grain size is uniformly reached to the critical equiaxed submicron crystal, the plasticity of the bar material is improved while the high strength of the bar material is maintained, and the two are well matched.

[0011] The preparation method of the high-performance titanium-zirconium alloy small-size bar material for dentistry has the characteristics that in step one, the specification diameter x height of the titanium-zirconium alloy cylindrical ingot is φ160 mm x 320 mm; in step two, the diameter of the round forging bar blank is φ50 mm; in step three, the diameter of the round rolling bar is φ14 mm-φ22.5 mm; and in step four, the diameter of the processing state small-size bar material is φ6 mm-φ10 mm.

[0012] The preparation method of the small-specification rod of the high-performance titanium-zirconium alloy for dental use has the characteristics that the heating temperature of the hot forming isothermal forging in the step one is 800-900 DEG C, the holding time is 60-90 min, and the deformation amount of each pass of the pressing is 50%, and the pressing speed is 0.3-0.4 mm / s.

[0013] The preparation method of the small-specification rod of the high-performance titanium-zirconium alloy for dental use has the characteristics that the temperature of the finish forging in the step two is 750-800 DEG C, and the holding time is 60 min.

[0014] The preparation method of the small-specification rod of the high-performance titanium-zirconium alloy for dental use has the characteristics that the deformation amount of each pass of the warm rolling in the step three is 15-25%, the total deformation amount is 80-92%, the temperature of the warm rolling is kept at 600-700 DEG C, and the holding time is 30-60 min.

[0015] The preparation method of the small-specification rod of the high-performance titanium-zirconium alloy for dental use has the characteristics that the total deformation amount of the cold rotary forging in the step four is 72-86%, and the annealing is carried out after each pass of the cold rotary forging, the annealing temperature of the cold rotary forging is 500-550 DEG C, and the holding time is 20-30 min.

[0016] The preparation method of the small-specification rod of the high-performance titanium-zirconium alloy for dental use has the characteristics that the temperature of the vacuum annealing in the step five is 600-700 DEG C, and the holding time is 10-30 min.

[0017] Compared with the prior art, the preparation method of the small-specification rod of the high-performance titanium-zirconium alloy for dental use has the following advantages:

[0018] 1. The titanium-zirconium alloy cylindrical ingot with the oxygen mass content less than 0.15% is selected as the raw material, so that the impurity elements of the titanium-zirconium alloy meet the clean requirement of the dental instruments, and the internal defects of the crystal caused by the trace impurity elements are effectively prevented, and the fracture failure of the dental end product is avoided.

[0019] 2. The isothermal forging is adopted to fully break the grains in the raw material to obtain the preliminary fine-grained structure, and then the finish forging process is adopted to perform the radial forging on the fine-grained square rod blank to obtain the round forging rod blank, so that the radial bearing of the square rod blank is uniformly extruded, the crack and the forging ratio are reduced, and the surface quality and the internal quality of the target product rod are improved.

[0020] 3. The temperature of the warm rolling process is controlled to be the recrystallization temperature of the titanium-zirconium alloy, the final uniform deformation of the internal structure of the rod is realized, the generation of the processing streamline is reduced, and the structure stability and the tensile strength of the target product rod are improved.

[0021] 4. By controlling the cold forging process, this invention ensures that the deformation amount reaches the processing deformation limit of small-diameter bars, and improves the straightness and accuracy of the processed small-diameter bars, providing a good foundation for subsequent annealing.

[0022] 5. The titanium-zirconium alloy small-sized rods prepared by this invention have high cleanliness, low oxygen content, fine and uniform microstructure, high strength and plasticity. The tensile strength can usually reach more than 700 MPa required for dental implants, and the elongation can reach more than 15%. Moreover, the two are well matched and are suitable for dental use.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] Figure 1 This is a microstructure diagram of the high-performance titanium-zirconium alloy small-diameter rods prepared in Example 1 of the present invention.

[0025] Figure 2 This is a microstructure diagram of the high-performance titanium-zirconium alloy small-diameter rods prepared in Example 2 of the present invention.

[0026] Figure 3 This is a microstructure diagram of the high-performance titanium-zirconium alloy small-diameter rods prepared in Example 3 of the present invention.

[0027] Figure 4 This is a microstructure diagram of the high-performance titanium-zirconium alloy small-diameter rods prepared in Example 4 of the present invention. Detailed Implementation

[0028] Example 1

[0029] This embodiment includes the following steps:

[0030] Step 1: Take a titanium-zirconium alloy cylindrical ingot with an oxygen content of less than 0.15% and a diameter × height of φ160mm × 320mm and place it on a 630T hot forming equipment for hot forming isothermal forging. The heating temperature is 800℃ and the holding time is 90min. Press the ingot sequentially along the longitudinal Y-axis, transverse X-axis and transverse Z-axis of the titanium-zirconium alloy cylindrical ingot according to the three-dimensional coordinate system. The deformation amount of each pressing pass is 50% and the pressing speed is 0.3mm / s. After the ingot is formed, it is water-cooled to obtain a square bar ingot.

[0031] Step 2: Place the square bar billet obtained in Step 1 on a precision forging machine for precision forging. The precision forging temperature is 750℃ and the holding time is 60min to obtain a round forging billet with a diameter of φ50mm.

[0032] Step three, the round forging bar blank obtained in step two is warm-rolled by adopting a transverse rod rolling mill, the pass deformation is 15%, the total deformation is 80%, the warm-rolling temperature is kept at 600 DEG C, and the holding time is 30 min, then the round bar is cross-rolled through square, round, flat, and flat passings in turn, and then is rolled through two passings of round passings, and the diameter of the round bar obtained after air cooling is φ22.5 mm;

[0033] Step four, the round bar obtained in step three is cold rotary forged by adopting a DH7-4 precision rotary forging machine, the total deformation of the cold rotary forging is 80%, the annealing temperature of the cold rotary forging is 500 DEG C, and the holding time is 20 min, and the diameter of the processed small-size rod obtained is φ10 mm;

[0034] Step five, the processed small-size rod obtained in step four is vacuum annealed, the vacuum annealing temperature is 600 DEG C, and the holding time is 30 min, and the high-performance titanium-zirconium alloy small-size rod for dentistry is obtained.

[0035] Example 2

[0036] The embodiment comprises the following steps:

[0037] Step one, a titanium-zirconium alloy cylindrical ingot blank with an oxygen mass content less than 0.15% and a specification diameter x height of φ160 mm x 320 mm is placed on a 630T hot forming equipment to perform hot forming isothermal forging, the heating temperature is 850 DEG C, the holding time is 70 min, and the blank is pressed along the longitudinal Y axis, the transverse X axis, and the transverse Z axis of the titanium-zirconium alloy cylindrical ingot blank in turn according to a three-dimensional coordinate system, the pass deformation of the pressing is 50% respectively, the pressing speed is 0.3 mm / s, the blank is water-cooled after pressing, and a square bar blank is obtained;

[0038] Step two, the square bar blank obtained in step one is placed on a precision forging machine to perform precision forging, the precision forging temperature is 780 DEG C, and the holding time is 60 min, and a round forging bar blank with a diameter of φ50 mm is obtained;

[0039] Step three, the round forging bar blank obtained in step two is warm-rolled by adopting a transverse rod rolling mill, the pass deformation is 20%, the total deformation is 85%, the warm-rolling temperature is kept at 650 DEG C, and the holding time is 50 min, then the round bar is cross-rolled through square, round, flat, and flat passings in turn, and then is rolled through two passings of round passings, and the diameter of the round bar obtained after air cooling is φ19 mm;

[0040] Step four, the round bar obtained in step three is cold rotary forged by adopting a DH7-4 precision rotary forging machine, the total deformation of the cold rotary forging is 72%, the annealing temperature of the cold rotary forging is 550 DEG C, and the holding time is 25 min, and the diameter of the processed small-size rod obtained is φ10 mm;

[0041] Step five, vacuum annealing the processed small-size rod obtained in step four, the vacuum annealing temperature is 650℃, the holding time is 20min, to obtain the high-performance titanium-zirconium alloy small-size rod for dentistry.

[0042] Example 3

[0043] This example includes the following steps:

[0044] Step one, the titanium-zirconium alloy cylindrical ingot with oxygen content less than 0.15% and size diameter x height of φ160mm x 320mm is placed on the 630T hot forming equipment to perform hot forming isothermal forging, the heating temperature is 900℃, the holding time is 90min, and the pressing is performed along the longitudinal Y axis, transverse X axis and transverse Z axis of the titanium-zirconium alloy cylindrical ingot in sequence according to the three-dimensional coordinate system, the deformation amount of each pass is 50%, the pressing speed is 0.4mm / s, and the water cooling is performed after the billet preparation to obtain a square bar blank;

[0045] Step two, the square bar blank obtained in step one is placed on the precision forging machine to perform precision forging, the precision forging temperature is 800℃, the holding time is 60min, and a round forging bar blank with a diameter of φ50mm is obtained;

[0046] Step three, the round forging bar blank obtained in step two is warm rolled by using a transverse rod rolling mill, the deformation amount of each pass is 25%, the total deformation amount is 90%, and the warm rolling temperature is kept at 700℃, the holding time is 60min, then the square, round, flat, flat pass is circularly crossed and rolled, and then two passes of round pass rolling are performed, and the air cooling is performed to obtain a round rolling rod with a diameter of φ16mm;

[0047] Step four, the round rolling rod obtained in step three is cold rotary forged by using a DH7-4 precision rotary forging machine, the total deformation amount of cold rotary forging is 86%, the annealing temperature of cold rotary forging is 550℃, and the holding time is 30min, to obtain a processed small-size rod with a diameter of φ6mm;

[0048] Step five, vacuum annealing the processed small-size rod obtained in step four, the vacuum annealing temperature is 700℃, the holding time is 10min, to obtain the high-performance titanium-zirconium alloy small-size rod for dentistry.

[0049] Example 4

[0050] This example includes the following steps:

[0051] Step one, the titanium-zirconium alloy cylindrical ingot with an oxygen mass content less than 0.15% and a specification diameter x height of φ160 mm x 320 mm is placed on a 630T hot forming equipment to perform hot forming isothermal forging, a heating temperature is 880°C, a holding time is 80 min, and the titanium-zirconium alloy cylindrical ingot is sequentially pressed along a longitudinal Y-axis, a transverse X-axis and a transverse Z-axis direction according to a three-dimensional coordinate system, a deformation amount of each pass is 50%, a pressing speed is 0.3 mm / s, and after the billet is prepared, water cooling is performed to obtain a square bar blank;

[0052] Step two, the square bar blank obtained in step one is placed on a precision forging machine to perform precision forging, a precision forging temperature is 780°C, a holding time is 60 min, and a circular forging bar blank with a diameter of φ50 mm is obtained;

[0053] Step three, the circular forging bar blank obtained in step two is subjected to warm rolling by adopting a cross-bar rolling mill, a deformation amount of each pass is 22%, a total deformation amount is 92%, a warm rolling temperature is kept at 680°C, a holding time is 60 min, then the bar is sequentially and crossly rolled through square, circular, flat and flat-shaped grooves, and then is rolled through two passes of circular grooves, and after air cooling, a circular rolling bar with a diameter of φ14 mm is obtained;

[0054] Step four, the circular rolling bar obtained in step three is subjected to cold rotary forging by adopting a DH7-4 precision rotary forging machine, a total deformation amount of cold rotary forging is 82%, an annealing temperature of cold rotary forging is 550°C, and a holding time is 30 min, and a processing state small-specification bar with a diameter of φ6 mm is obtained;

[0055] Step five, the processing state small-specification bar obtained in step four is subjected to vacuum annealing, a vacuum annealing temperature is 600°C, a holding time is 20 min, and a high-performance titanium-zirconium alloy small-specification bar for dentistry is obtained.

[0056] According to GB / T 13810-2017 "Titanium and Titanium Alloy for Surgical Implants" and GB / T 228.1-2021 "Room Temperature Bar Tensile Test Sample", the room temperature performance of the high-performance titanium-zirconium alloy small-specification bar for dentistry prepared in Example 1 to Example 4 of the application is tested, and the results are shown in Table 1.

[0057] Table 1 Performance of the high-performance titanium-zirconium alloy small-specification bar for dentistry prepared in Example 1 to Example 4 of the application

[0058]

[0059] As shown in Table 1, the dental high-performance titanium-zirconium alloy small-size rod prepared by the embodiments 1-6 has fine microstructure, the tensile strength is 767-877 MPa, the yield strength is 638-782 MPa, the elongation is 15-20%, and the microhardness HV is 254-268, which indicates that the dental titanium-zirconium rod prepared by the method has high strength, high plasticity and fine and stable microstructure. The performance of the dental high-performance titanium-zirconium alloy small-size rod prepared by the embodiments 1-4 is compared with that of the currently clinically commonly used pure titanium TA4 rod, the microstructure of the dental high-performance titanium-zirconium alloy small-size rod reaches A1 grade microstructure, and thus the tensile strength, yield strength, elongation and microhardness are all superior to those of the commonly used TA4 rod.

[0060] The above description is only the preferred embodiments of the present application, and does not limit the present application in any way. Any simple modification, change and equivalent change made according to the technical essence of the present application to the above embodiments are still within the protection scope of the technical scheme of the present application.

Claims

1. A method for preparing small-diameter high-performance titanium-zirconium alloy rods for dental use, characterized in that, The method includes the following steps: Step 1: Take a titanium-zirconium alloy cylindrical ingot with an oxygen content of less than 0.15% and place it on a hot forming equipment for hot forming isothermal forging. Press it sequentially along the longitudinal Y-axis, transverse X-axis, and transverse Z-axis of the titanium-zirconium alloy cylindrical ingot according to the three-dimensional coordinate system. After the ingot is formed, it is water-cooled to obtain a square bar ingot. Step 2: Place the square bar billet obtained in Step 1 on a precision forging machine for precision forging to obtain a round forged bar billet; Step 3: The round forged billet obtained in Step 2 is warm rolled using a transverse bar mill, and then sequentially rolled through square, round, flat, and flat passes in a cyclic cross-rolling process, followed by two passes through a round pass. After air cooling, a round rolled bar is obtained. The deformation per pass of the warm rolling is 15%~25%, the total deformation is 80%~92%, and the temperature of the warm rolling is maintained at 600℃~700℃ for 30min~60min. Step 4: Use a precision rotary forging machine to perform cold rotary forging on the round rolled bar obtained in Step 3 to obtain a small-sized bar in the processed state; the total deformation of the cold rotary forging is 72%~86%, and annealing is performed after each cold rotary forging pass. The annealing temperature of the cold rotary forging is 500℃~550℃, and the holding time is 20min~30min. Step 5: Vacuum anneal the processed small-diameter bars obtained in Step 4 to obtain high-performance titanium-zirconium alloy small-diameter bars for dental use; the microstructure of the high-performance titanium-zirconium alloy small-diameter bars for dental use is A1 grade, and the mechanical properties are: tensile strength 767MPa~877MPa, yield strength 638MPa~782MPa, elongation 15%~20%, and microhardness HV 254~268.

2. The method for preparing a small-diameter high-performance titanium-zirconium alloy bar for dental use according to claim 1, characterized in that, The diameter × height of the titanium-zirconium alloy cylindrical ingot in step one is φ160mm × 320mm; the diameter of the round forged bar in step two is φ50mm; the diameter of the round rolled bar in step three is φ14mm~φ22.5mm; and the diameter of the processed small-sized bar in step four is φ6mm~φ10mm.

3. The method for preparing a small-diameter high-performance titanium-zirconium alloy bar for dental use according to claim 1, characterized in that, The heating temperature for the hot forming isothermal forging in step one is 800℃~900℃, the holding time is 60min~90min, the deformation amount of each pressing pass is 50%, and the pressing speed is 0.3mm / s~0.4mm / s.

4. The method for preparing a small-diameter high-performance titanium-zirconium alloy bar for dental use according to claim 1, characterized in that, The precision forging temperature in step two is 750℃~800℃, and the holding time is 60min.

5. The method for preparing a small-diameter high-performance titanium-zirconium alloy bar for dental use according to claim 1, characterized in that, The vacuum annealing temperature in step five is 600℃~700℃, and the holding time is 10min~30min.

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