Preparation method of high-strength pure titanium wire for dentistry

Abstract

The invention discloses a preparation method of a high-strength pure titanium wire for dentistry. The preparation method comprises the following steps: step 1, preparing a pure titanium cast ingot with uniform components by adopting vacuum arc melting; 2, the pure titanium cast ingot obtained in the step 1 is subjected to multi-heating-number forging and rolling to be machined into a coiled wire blank with the diameter being 6.5 mm to 18 mm; 3, the coiled wire blank obtained in the step 2 is subjected to drawing and rounding, the drawing amount ranges from 0.5 mm to 6 mm, and then surface defects are removed through machining and scaling by 0.5 mm; fourthly, the wire rod obtained in the third step is placed in a heat treatment furnace to be subjected to recrystallization heat treatment, and air cooling is conducted after the wire rod is discharged out of the furnace; and 5, the wire obtained in the step 4 is subjected to cold rolling or cold drawing deformation, the deformation amount ranges from 15.3% to 66.7%, and then the pure titanium wire with the specification ranging from phi 3.0 mm to phi 10.0 mm is obtained through finishing. By adopting the method, the high-strength pure titanium wire for the dentistry, which is relatively high in strength and good in plasticity, can be obtained.

Description

Technical Field

[0001] The invention belongs to the technical field of nonferrous metal material processing methods, and specifically relates to a method for preparing high-strength pure titanium wire for dentistry. Background Art

[0002] In the field of medical dental implants, pure titanium is close to human bone in density and strength, and has good biomechanical adaptability. In addition, the titanium surface oxide film (TiO X ) makes the implant have good biocompatibility, so that the connection and fit between the implant and the tooth alveolar are tighter, so pure titanium products are ideal orthopedic / dental replacement materials. However, the mechanical strength of traditional annealed pure titanium is low and the wear resistance is poor. Its fatigue performance is poor after implantation in the oral cavity. The mechanical strength of completely cold-processed pure titanium fluctuates greatly, the plasticity is poor, and the molding process is difficult. Pure titanium wires in the above two states cannot meet the requirements of implant use. Therefore, it is urgent to develop a preparation method for dental pure titanium wires that takes into account both strength and plasticity. Summary of the invention

[0003] The purpose of the present invention is to provide a method for preparing a high-strength pure titanium wire for dentistry, which can obtain a high-strength pure titanium wire for dentistry with high strength and good plasticity.

[0004] The technical solution adopted by the present invention is a method for preparing high-strength pure titanium wire for dentistry, which is specifically implemented according to the following steps: Step 1, preparing a pure titanium ingot with uniform composition by vacuum arc melting; Step 2, subjecting the pure titanium ingot obtained in step 1 to multi-fire forging and rolling to process into a coiled wire blank of Φ6.5 mm to Φ18 mm; Step 3, drawing the coiled wire blank obtained in step 2 to a round shape, the drawing amount is 0.5 mm to 6 mm, and then machine-stripping 0.5 mm to remove surface defects; Step 4, placing the coiled wire obtained in step 3 in a heat treatment furnace for recrystallization heat treatment, and air cooling after being taken out of the furnace; Step 5, cold rolling or cold drawing the wire obtained in step 4 to deform the wire by 15.3% to 66.7%, and then finishing to obtain pure titanium wire with a specification of Φ3.0 mm to Φ10.0 mm.

[0005] The present invention is also characterized in that: In step 1, the vacuum arc melting is performed at least twice.

[0006] The mass percentage contents of each element in the pure titanium ingot prepared in step 1 are: O content ≤0.40%, Fe content ≤0.50%, C content ≤0.08%, N content ≤0.05%, H content ≤0.015%, and the balance is Ti.

[0007] In step 2, the forging adopts multi-fire free forging or precision forging, and the rolling process adopts a horizontal rolling mill or a high-speed wire rolling mill.

[0008] In step 4, the temperature of the recrystallization heat treatment is 550°C to 750°C, and the holding time is 1h to 4h.

[0009] The beneficial effects of the present invention are: The method of the present invention adopts ingot melting, forging, rolling, drawing, recrystallization heat treatment, rolling or drawing strengthening, surface finishing and other means to finally obtain high-strength pure titanium wire with excellent comprehensive performance. The finished product specification range covers Φ3.0~Φ10mm, the grain size is better than grade 6.0, the tensile strength Rm is 750~930MPa, the yield strength Rp0.2≥500MPa, the cross-sectional shrinkage rate A≥12%, and the elongation Z≥35%, which well meets the application needs of high-strength pure titanium wire for dentistry. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 This is a high-magnification microstructure morphology of the high-strength pure titanium Φ3.0 mm wire prepared in Example 1 of the present invention; Figure 2 This is a high-magnification microstructure morphology of the high-strength pure titanium Φ5.0 mm wire prepared in Example 2 of the present invention; Figure 3 This is a high-magnification microstructure morphology of the high-strength pure titanium Φ8.0 mm wire prepared in Example 3 of the present invention; Figure 4 This is a high-magnification microstructure morphology of a high-strength pure titanium Φ10.0 mm wire prepared in Example 4 of the present invention; Figure 5 1 is a graph showing the room temperature mechanical properties test results of the high-strength pure titanium wires prepared in Examples 1-4 of the present invention. DETAILED DESCRIPTION

[0011] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0012] The method for preparing the high-strength pure titanium wire for dentistry of the present invention is specifically implemented according to the following steps: Step 1: Ingot smelting preparation A pure titanium ingot with uniform composition is prepared by vacuum arc melting for not less than 2 times, and the mass percentage contents of each element in the ingot are: O content ≤ 0.40%, Fe content ≤ 0.50%, C content ≤ 0.08%, N content ≤ 0.05%, H content ≤ 0.015%, and the balance is Ti.

[0013] Step 2: Billet forging and rolling The pure titanium ingot obtained in step 1 is subjected to multi-fire forging and rolling to be processed into a coiled wire blank of Φ6.5mm~Φ18mm. The forging can be performed by multi-fire free forging or fine forging, and the rolling process can be performed by a horizontal rolling mill or a high-speed wire rolling mill.

[0014] Step 3: Surface pulling and peeling The coiled wire blank obtained in step 2 is drawn and rounded, the drawing amount is 0.5 mm to 6 mm, and then machined and peeled by 0.5 mm to remove surface defects; Step 4: Recrystallization heat treatment The coiled wire obtained in step 3 is placed in a heat treatment furnace for recrystallization heat treatment at a temperature of 550°C to 750°C for 1h to 4h, and air-cooled after being taken out of the furnace. After heat treatment, the grain size of the high-magnification microstructure rating is ≥ 6.0.

[0015] Step 5: Drawing and finishing The wire obtained in step 4 is subjected to cold rolling / cold drawing deformation by a wire drawing machine or a cold rolling machine, with a deformation amount of 15.3% to 66.7%, and then is finished to obtain a high-strength pure titanium wire for dentistry with a specification of Φ3.0mm to Φ10.0mm.

[0016] Example 1 Step 1: Ingot smelting preparation Pure titanium ingots with uniform composition were prepared by two vacuum arc melting processes. The contents of each element at the head and tail of the prepared pure titanium ingots were: O content was 0.35% and 0.34%, Fe content was 0.36% and 0.35%, C content was 0.015% and 0.017%, N content was 0.020% and 0.018%, H content was 0.006% and 0.007%, and the balance was Ti.

[0017] Step 2: Billet forging and rolling The pure titanium ingot obtained in step 1 is subjected to multiple forging and rolling to prepare a Φ6.5 mm coiled wire blank; Step 3: Surface pulling and peeling The coiled wire blank obtained in step 2 is drawn and rounded to Φ6.0 mm, and then machined and peeled to Φ5.5 mm to remove surface defects; Step 4: Recrystallization heat treatment The Φ5.5 mm coiled wire obtained in step 3 is placed in a heat treatment furnace for recrystallization heat treatment at a temperature of 550° C. for 1 h, and then air-cooled after being taken out of the furnace.

[0018] Step 5: Drawing and finishing The wire that has undergone the recrystallization heat treatment in step 4 is drawn to Φ3.2 mm using a wire drawing machine with a deformation of 66.1%, and then refined to obtain a Φ3.0 mm high-strength pure titanium wire for dental use.

[0019] Example 2 Step 1: Ingot smelting preparation Pure titanium ingots with uniform composition were prepared by two vacuum arc melting processes. The contents of each element at the head and tail of the prepared pure titanium ingots were: O content was 0.33% and 0.31%, Fe content was 0.04% and 0.05%, C content was 0.020% and 0.018%, N content was 0.018% and 0.016%, H content was 0.004% and 0.005%, and the balance was Ti.

[0020] Step 2: Billet forging and rolling The pure titanium ingot obtained in step 1 is subjected to multiple forging and rolling to prepare a Φ10.0 mm coiled wire blank; Step 3: Surface pulling and peeling The coiled wire blank obtained in step 2 is drawn and rounded to Φ8.0 mm, and then machined and peeled to Φ7.5 mm to remove surface defects; Step 4: Recrystallization heat treatment The Φ7.5 mm coiled wire obtained in step 3 is placed in a heat treatment furnace for recrystallization heat treatment at a temperature of 750° C. for 2 h, and then air-cooled after being taken out of the furnace.

[0021] Step 5: Drawing and finishing The wire that has undergone the recrystallization heat treatment in step 4 is rolled to Φ5.3 mm using a cold rolling mill with a deformation of 50.1%, and then refined to obtain a Φ5.0 mm high-strength pure titanium wire for dental use.

[0022] Example 3 Step 1: Ingot smelting preparation Pure titanium ingots with uniform composition were prepared by two vacuum arc melting processes. The contents of each element at the head and tail of the prepared pure titanium ingots were: O content was 0.30% and 0.28%, Fe content was 0.14% and 0.15%, C content was 0.008% and 0.007%, N content was 0.010% and 0.009%, H content was 0.007% and 0.005%, and the balance was Ti.

[0023] Step 2: Billet forging and rolling The pure titanium ingot obtained in step 1 is subjected to multiple forging and rolling to prepare a Φ14.0 mm coiled wire blank; Step 3: Surface pulling and peeling The coiled wire blank obtained in step 2 is drawn and rounded to Φ12.0 mm, and then machined and peeled to Φ11.5 mm to remove surface defects; Step 4: Recrystallization heat treatment The Φ11.5 mm coiled wire obtained in step 3 is placed in a heat treatment furnace for recrystallization heat treatment at a temperature of 680° C. for 3 h, and then air-cooled after being taken out of the furnace.

[0024] Step 5: Drawing and finishing The wire that has undergone the recrystallization heat treatment in step 4 is drawn to Φ9.4 mm using a wire drawing machine with a deformation of 33.2%, and then refined to obtain a Φ8.0 mm high-strength pure titanium wire for dental use.

[0025] Example 4 Step 1: Ingot smelting preparation Pure titanium ingots with uniform composition were prepared by two vacuum arc melting processes. The contents of each element at the head and tail of the prepared pure titanium ingots were: O content was 0.28% and 0.29%, Fe content was 0.22% and 0.23%, C content was 0.012% and 0.011%, N content was 0.015% and 0.014%, H content was 0.006% and 0.006%, and the balance was Ti.

[0026] Step 2: Billet forging and rolling The pure titanium ingot obtained in step 1 is subjected to multiple forging and rolling to prepare a Φ18.0 mm coiled wire blank; Step 3: Surface pulling and peeling The coiled wire blank obtained in step 2 is drawn and rounded to Φ12.0 mm, and then machined and peeled to Φ11.5 mm to remove surface defects; Step 4: Recrystallization heat treatment The Φ11.5 mm coiled wire obtained in step 3 is placed in a heat treatment furnace for recrystallization heat treatment at a temperature of 650° C. for 4 h, and then air-cooled after being taken out of the furnace.

[0027] Step 5: Drawing and finishing The wire that has undergone the recrystallization heat treatment in step 4 is drawn to Φ10.4 mm using a wire drawing machine with a deformation of 15.3%, and then refined to obtain a Φ10.0 mm high-strength pure titanium wire for dental use.

[0028] The high-strength pure titanium Φ3.0 mm, Φ5.0 mm, Φ8.0 mm, and Φ10.0 mm wires obtained in Examples 1-4 were tested, and their high-magnification microstructure morphology was analyzed using an optical microscope. The results are as follows: Figure 1~Figure 4 The tensile strength and yield strength of the finished wire are tested by strength testing equipment, and the elongation and cross-sectional expansion ratio are tested by elongation tester. The test results are shown in Figure 5 shown.

[0029] Depend on Figure 1~Figure 4 It can be seen that the grain size of the finished wire prepared by the method of the present invention can reach level 6 to level 10. Figure 5 It can be seen that the tensile strength Rm of the finished wire is 750~930MPa, the yield strength Rp0.2≥500MPa, the cross-sectional shrinkage rate A≥12%, and the elongation Z≥35%, which can well meet the application requirements of high-strength pure titanium wire for dentistry.

[0030] Comparative Example 1 This comparative example is basically the same as Example 1, except that the drawing deformation in step 5 is 70.1%. The specific steps are: Steps 1 to 4 are the same as those in Example 1.

[0031] Step 5: Drawing and finishing The wire that has undergone the recrystallization heat treatment in step 4 is drawn to Φ3.0 mm using a wire drawing machine with a deformation amount of 70.2%, and then refined to obtain a Φ2.8 mm pure titanium wire.

[0032] The performance of the pure titanium wire obtained in this comparative example was tested, and the tensile strength Rm was measured to be 955 / 961MPa, the yield strength Rp0.2 was 866 / 872MPa, the cross-sectional shrinkage A was 11.0% / 10.5%, and the elongation Z was 33% / 34%. It can be seen that after using this deformation, the tensile strength of the material is significantly increased and the plasticity is significantly reduced, which does not meet the application requirements. Therefore, the upper limit of the drawing deformation should be strictly controlled.

[0033] Comparative Example 2 This comparative example is basically the same as Example 1, except that the drawing deformation in step 5 is 14.0%. The specific steps are: Steps 1 to 4 are the same as those in Example 1.

[0034] Step 5: Drawing and finishing The wire that has undergone the recrystallization heat treatment in step 4 is drawn to Φ5.1 mm using a wire drawing machine with a deformation of 14.0%, and then refined to obtain a Φ4.5 mm pure titanium wire.

[0035] The performance of the pure titanium wire obtained in this comparative example was tested, and the tensile strength Rm was 745 / 740MPa, the yield strength Rp0.2 was 636 / 642MPa, the cross-sectional shrinkage A was 24.0% / 25.0%, and the elongation Z was 54% / 54%. It can be seen that after using this deformation, the tensile strength of the material is significantly reduced and does not meet the application requirements. Therefore, the lower limit of the drawing deformation should be strictly controlled.

[0036] Comparative Example 3 This comparative example is basically the same as Example 1, except that the recrystallization heat treatment temperature in step 4 is 770°C. The specific steps are: Steps 1 to 3 are the same as those in Example 1.

[0037] Step 4: Recrystallization heat treatment The Φ5.5 mm coiled wire obtained in step 3 is placed in a heat treatment furnace for recrystallization heat treatment at a temperature of 770° C. for 1 h, and then air-cooled after being taken out of the furnace.

[0038] Step 5 is the same as in Example 1.

[0039] The wire obtained in step 4 of this comparative example was graded for grain size, and the grain size of the material was measured to be 5-5.5, which does not meet the application requirements. It can be seen that too high a recrystallization heat treatment temperature will affect the grain size of the material. Only within the temperature range limited by the method of the present invention can a wire with a grain size that meets the requirements be obtained.

Claims

1. A method for preparing high-strength pure titanium wire for dentistry, characterized in that: Follow the steps below to implement it: Step 1, preparing a pure titanium ingot with uniform composition by vacuum arc melting; Step 2, subjecting the pure titanium ingot obtained in step 1 to multi-fire forging and rolling to process into a coiled wire blank of Φ6.5 mm to Φ18 mm; Step 3, drawing the coiled wire blank obtained in step 2 to a round shape, the drawing amount is 0.5 mm to 6 mm, and then machine-stripping 0.5 mm to remove surface defects; Step 4, placing the coiled wire obtained in step 3 in a heat treatment furnace for recrystallization heat treatment, and air cooling after being taken out of the furnace; Step 5, cold rolling or cold drawing the wire obtained in step 4 to deform the wire by 15.3% to 66.7%, and then finishing to obtain pure titanium wire with a specification of Φ3.0 mm to Φ10.0 mm.

2. The method for preparing high-strength pure titanium wire for dentistry according to claim 1, characterized in that: In step 1, the vacuum arc melting is performed at least twice.

3. The method for preparing high-strength pure titanium wire for dentistry according to claim 1, characterized in that: The mass percentage contents of each element in the pure titanium ingot prepared in step 1 are: O content ≤0.40%, Fe content ≤0.50%, C content ≤0.08%, N content ≤0.05%, H content ≤0.015%, and the balance is Ti.

4. The method for preparing high-strength pure titanium wire for dentistry according to claim 1, characterized in that: In step 2, the forging adopts multi-fire free forging or precision forging, and the rolling process adopts a horizontal rolling mill or a high-speed wire rolling mill.

5. The method for preparing high-strength pure titanium wire for dentistry according to claim 1, characterized in that: In step 4, the temperature of the recrystallization heat treatment is 550°C to 750°C, and the holding time is 1h to 4h.

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