阅读说明：本技术 一种万向复位螺钉座钛合金棒材的制备方法 (Preparation method of universal reset screw base titanium alloy bar ) 是由 柏春光 张志强 赵建 杨锐 于 2020-04-23 设计创作，主要内容包括：本发明属于医疗用钛合金材料加工技术领域,具体涉及一种万向复位螺钉座钛合金棒材的制备方法。钛合金的化学成分及质量百分比为：Al 5.9～6.4%,V 3.9～4.4%,Fe 0.15～0.22%,O 0.09～0.13%,C≤0.05%,H≤0.005%,N≤0.01%,余量为Ti；首先通过熔炼、锻造、轧制工序获得圆棒坯料；然后采用β单相区均匀化退火处理工艺,获得均匀的细晶针状马氏体组织,采用通电矫直和双曲线矫直复合工艺进行矫直,控制通电矫直温度在780℃以下,获得平衡的残余应力状态；最后进行去应力退火、无心磨削制备出成品棒材。本发明可以生产出基本无应力的医疗用Ti-6Al-4V合金棒材,并具备优异的疲劳寿命,为制造骨科医疗器械万向复位螺钉座提供合格原材料。(The invention belongs to the technical field of processing of medical titanium alloy materials, and particularly relates to a preparation method of a titanium alloy bar of a universal reset screw seat. The titanium alloy comprises the following chemical components in percentage by mass: 5.9 to 6.4 percent of Al, 3.9 to 4.4 percent of V, 0.15 to 0.22 percent of Fe, 0.09 to 0.13 percent of O, less than or equal to 0.05 percent of C, less than or equal to 0.005 percent of H, less than or equal to 0.01 percent of N, and the balance of Ti; firstly, obtaining a round bar blank through smelting, forging and rolling processes; then adopting a beta single-phase region homogenizing annealing treatment process to obtain a uniform fine-grained acicular martensite structure, adopting a power-on straightening and hyperbolic straightening composite process to straighten, and controlling the power-on straightening temperature to be below 780 ℃ to obtain a balanced residual stress state; finally, stress relief annealing and centerless grinding are carried out to prepare the finished bar. The method can produce the medical Ti-6Al-4V alloy bar material with basically no stress, has excellent fatigue life, and provides qualified raw materials for manufacturing the universal reset screw seat of the orthopedic medical instrument.)

1. The preparation method of the universal reset screw seat titanium alloy bar is characterized in that the universal reset screw seat titanium alloy bar comprises the following chemical components in percentage by mass: 5.9 to 6.4 percent of Al element, 3.9 to 4.4 percent of V element, 0.15 to 0.22 percent of Fe element, 0.09 to 0.13 percent of O element, less than or equal to 0.05 percent of C element, less than or equal to 0.005 percent of H element, less than or equal to 0.01 percent of N element, and the balance of Ti;

the method comprises the following steps:

step one, preparing a titanium alloy ingot by adopting vacuum consumable melting;

secondly, forging by adopting a quick forging machine and a precision forging machine, and carrying out homogenization annealing treatment;

step three, rolling by adopting a transverse rolling mill;

fourthly, drawing by adopting a chain type drawing machine;

fifthly, straightening by adopting an electrified tension straightening machine;

sixthly, stress relief annealing treatment is carried out on the electrically straightened bar;

seventhly, performing fine straightening by adopting a hyperbolic straightening machine;

step eight, stress relief annealing treatment is carried out on the bar after the hyperbolic curve straightening;

and step nine, performing centerless grinding on the bar to prepare the finished bar with the specification.

2. The preparation method of the titanium alloy bar of the universal reduction screw seat according to claim 1, wherein in the first step, titanium sponge, metal Al, intermediate alloy AlV, metal Fe and compound TiO are required₂And preparing materials according to the components of the titanium alloy, and smelting for three times by adopting vacuum consumable melting to obtain the titanium alloy ingot.

3. The preparation method of the titanium alloy bar for the universal reduction screw base according to claim 1, wherein in the second step, cogging forging is performed at 1050-1150 ℃, finish forging is performed at 900-1000 ℃, the heat preservation time is controlled to be 1.5-8 hours, and the deformation per firing is controlled to be 40-80%; and (3) carrying out homogenizing annealing treatment on the forged blank, wherein the homogenizing annealing treatment temperature is 30-50 ℃ above the beta transformation point of the titanium alloy, preserving the heat for 10-60 min, and carrying out water quenching to room temperature.

4. The preparation method of the titanium alloy bar for the universal reduction screw seat according to claim 1, wherein in the third step, the rolling temperature is controlled to be 880-930 ℃, the temperature is kept for 1-2 hours, and the deformation of each pass is controlled to be within 15%.

5. The preparation method of the titanium alloy bar of the universal reduction screw seat according to claim 1, wherein in the fourth step, the drawing temperature is controlled to be 700-800 ℃, the speed of the chain type drawing machine is 1-1.5 m/min, and the deformation is 20-40%.

6. The preparation method of the titanium alloy bar of the universal reduction screw seat according to claim 1, wherein in the fifth step, the electrified current is controlled to be 150-200A, and the temperature of the bar in the straightening process is less than 780 ℃.

7. The preparation method of the titanium alloy bar for the universal reduction screw seat according to claim 1, wherein in the sixth step, a box-type resistance furnace is selected for stress relief annealing treatment, the annealing temperature is 700-800 ℃, the heat preservation time is 2-4 hours, and the furnace is cooled to room temperature.

8. The preparation method of the titanium alloy bar of the universal reset screw seat according to claim 1, wherein the seventh step is to ensure that the bending degree of the bar after straightening is less than 0.3mm/m and the surface temperature of the bar during straightening is less than 70 ℃.

9. The preparation method of the titanium alloy bar for the universal reduction screw seat according to claim 1, wherein in the eighth step, a box-type resistance furnace is selected for stress relief annealing treatment, the annealing temperature is controlled to be 600-700 ℃, the heat preservation time is 2-4 hours, and the bar is air-cooled to room temperature.

10. The method for preparing the titanium alloy bar of the universal reduction screw seat according to claim 1, wherein in the ninth step, the centerless grinding amount is less than 0.06mm each time, and the surface of the finished product is polished.

Technical Field

The invention belongs to the technical field of processing of medical titanium alloy materials, and particularly relates to a preparation method of a titanium alloy bar of a universal reset screw seat.

Background

The titanium alloy has excellent biocompatibility and corrosion resistance, is nonmagnetic and nontoxic, and is widely used in the medical field. The Ti-6Al-4V alloy is widely applied to production and preparation of medical products, and titanium alloy rod wires produced by the prior art have large internal stress, so that stress imbalance can be caused by processing modes such as opening and the like in the subsequent machining process of the universal reset screw seat, the opening is expanded or contracted, and the precision of the medical products is damaged.

Disclosure of Invention

The residual stress of the Ti-6Al-4V alloy in the processing process causes the problem of flaring or necking of the universal reset screw seat bar during the production of medical products. The invention aims to solve the technical problem of providing a method for preparing a titanium alloy bar of a universal reset screw seat, and aims to solve the problem of flaring or necking of a Ti-6Al-4V alloy bar during production of medical products.

The technical scheme adopted by the invention is as follows:

a preparation method of a universal reset screw seat titanium alloy bar comprises the following chemical components in percentage by mass: 5.9 to 6.4 percent of Al element, 3.9 to 4.4 percent of V element, 0.15 to 0.22 percent of Fe element, 0.09 to 0.13 percent of O element, less than or equal to 0.05 percent of C element, less than or equal to 0.005 percent of H element, less than or equal to 0.01 percent of N element, and the balance of Ti;

the method comprises the following steps:

step one, preparing a titanium alloy ingot by adopting vacuum consumable melting;

secondly, forging by adopting a quick forging machine and a precision forging machine, and carrying out homogenization annealing treatment;

step three, rolling by adopting a transverse rolling mill;

fourthly, drawing by adopting a chain type drawing machine;

fifthly, straightening by adopting an electrified tension straightening machine;

sixthly, stress relief annealing treatment is carried out on the electrically straightened bar;

seventhly, performing fine straightening by adopting a hyperbolic straightening machine;

step eight, stress relief annealing treatment is carried out on the bar after the hyperbolic curve straightening;

and step nine, performing centerless grinding on the bar to prepare the finished bar with the specification.

The preparation method of the universal reset screw seat titanium alloy bar comprises the step one, wherein sponge titanium, metal Al, intermediate alloy AlV, metal Fe and compound TiO are required to be adopted₂And preparing materials according to the components of the titanium alloy, and smelting for three times by adopting vacuum consumable melting to obtain the titanium alloy ingot.

In the second step, cogging and forging are required to be carried out at 1050-1150 ℃, finish forging is carried out at 900-1000 ℃, the heat preservation time is controlled to be 1.5-8 hours, and the deformation per firing is controlled to be 40-80%; and (3) carrying out homogenizing annealing treatment on the forged blank, wherein the homogenizing annealing treatment temperature is 30-50 ℃ above the beta transformation point of the titanium alloy, preserving the heat for 10-60 min, and carrying out water quenching to room temperature.

The preparation method of the titanium alloy bar of the universal reset screw seat comprises the third step of controlling the rolling temperature to be 880-930 ℃, preserving heat for 1-2 hours and controlling the deformation of each pass to be within 15%.

The preparation method of the universal reset screw seat titanium alloy bar comprises the fourth step of controlling the drawing temperature to be 700-800 ℃, the speed of the chain type drawing machine to be 1-1.5 m/min and the deformation to be 20-40%.

In the fifth step of the preparation method of the titanium alloy bar of the universal reset screw seat, the electrified current is controlled to be 150-200A, and the temperature of the bar is less than 780 ℃ in the straightening process.

In the sixth step, a box-type resistance furnace is selected for stress relief annealing treatment, the annealing temperature is 700-800 ℃, the heat preservation time is 2-4 hours, and the furnace is cooled to the room temperature.

The preparation method of the titanium alloy bar of the universal reset screw seat comprises the seventh step of ensuring that the bending degree of the straightened bar is less than 0.3mm/m and the surface temperature of the bar is less than 70 ℃ in the straightening process.

And in the eighth step, a box-type resistance furnace is selected for stress relief annealing treatment, the annealing temperature is controlled to be 600-700 ℃, the heat preservation time is 2-4 hours, and the titanium alloy bar is air-cooled to room temperature.

In the ninth step, the centerless grinding amount is less than 0.06mm each time, and the surface of a finished product is polished.

The design idea of the invention is as follows:

the alloy comprises the following components in percentage by mass: 5.9 to 6.4 percent of Al element, 3.9 to 4.4 percent of V element, 0.15 to 0.22 percent of Fe element, 0.09 to 0.13 percent of O element, less than or equal to 0.05 percent of C element, less than or equal to 0.005 percent of H element, less than or equal to 0.01 percent of N element, and the balance of Ti; the design idea of the components is as follows: the high residual stress caused by the fact that the strength is improved by accumulating excessive deformation amount is reduced by improving the content of impurity elements Fe and O in the TC4 alloy and improving the strength of the low-clearance TC4 alloy.

The invention adopts a special processing technology, firstly, round bar blanks are obtained through the working procedures of smelting, forging and rolling; then adopting a beta single-phase region homogenizing annealing treatment process to obtain a uniform and fine acicular martensite structure, adopting a power-on straightening and hyperbolic straightening composite process to straighten, and controlling the power-on straightening temperature to be below 780 ℃ to obtain a balanced residual stress state; finally, stress relief annealing and centerless grinding are carried out to prepare the finished bar. The design idea of the processing technology is as follows: fine acicular martensite is formed in the alloy through single-phase zone annealing water quenching, and effective refinement of grain size can be realized under the subsequent small drawing deformation; then, when the electric straightening is carried out at a higher temperature, the growth of the tissue is limited, and the residual stress can be effectively reduced; after subsequent stress relief annealing, the alloy structure and performance can meet the standard requirements, the residual stress is low, and the problems of closing in and the like can not occur in the use of orthopedics.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the invention adopts the vacuum consumable furnace to carry out three times of smelting, thereby ensuring the uniformity and consistency of the material.

2. The invention can obtain uniform, fine and equiaxial tissues by homogenizing annealing treatment and combining large-deformation multi-heat forging, and meets the a-level standard.

3. According to the invention, by adopting the modes of electrified tension straightening, stress relief annealing and hyperbolic straightening and stress relief annealing, the tensile stress and the compressive stress introduced in the production process of the bar are effectively eliminated, and the problem of flaring or necking of the Ti-6Al-4V alloy bar in the production of universal reset screw seat products is solved.

4. The invention has simple required equipment and processing technology and can meet the requirement of batch production.

Drawings

FIG. 1 shows the metallographic results of a 18.0mm diameter Ti-6Al-4V alloy bar prepared in example 1.

FIG. 2 shows the metallographic results of a 16.0mm diameter Ti-6Al-4V alloy bar prepared in example 2.

FIG. 3 shows the metallographic results of a 14.0mm diameter Ti-6Al-4V alloy bar prepared in example 3.

FIG. 4 shows the metallographic results of a 12.0mm diameter Ti-6Al-4V alloy bar prepared in example 4.

Detailed Description

The present invention will be further described with reference to the following examples.