CN106319286A - Low-cost titanium alloy and preparation method thereof - Google Patents

Abstract

The application provides a low-cost titanium alloy and a preparation method thereof. The titanium alloy uses titanium as the main element, and the α-stable element B and the β-stable element Fe as alloy elements. The content of each component of the titanium alloy is: Fe : 0.5‑5wt.%, B: 0.05‑0.2wt.%, the balance is titanium and unavoidable impurities. The preparation method is as follows: according to the designed alloy composition ratio, the raw materials are added to the cold crucible suspension melting furnace with argon gas, and the ingot is obtained after repeated melting. The ingot is opened and forged above the phase transition point, and the forged alloy is sampled for heat treatment. , and finally carry out structure and performance characterization. The titanium alloy provided by this application has a uniform alloy composition, a fine structure, a tensile strength of 750MPa-850MPa, and an elongation of 10-15%. The alloy has the advantage of low cost and can replace some more expensive titanium alloys in some fields .

Description

A kind of low-cost titanium alloy and preparation method thereof

technical field

The application relates to a low-cost titanium alloy and a preparation method thereof, belonging to the technical field of titanium alloy materials.

Background technique

Due to their low density, high specific strength, high temperature resistance, corrosion resistance, non-magnetic, biocompatibility and other excellent properties, titanium and titanium alloys have been widely used in aviation, aerospace, ships and other fields. However, the high cost of titanium limits the use of titanium. And the application scope of titanium alloy, especially in the civil field. At present, most of the alloying elements in industrial titanium alloys use precious metals such as V, Mo, Nb, Zr, Sn and Ta, which makes the cost of titanium alloys remain high and affects the scope of use of titanium alloys.

At present, the ways to reduce the cost of titanium alloys include: reducing the cost of raw materials by improving the production method of raw materials (titanium sponge), using cheap alloying elements, optimizing the processing technology of titanium alloys, and optimizing the processing technology of titanium products. For example, the publication number is CN102828058A, and the invention title is "A Preparation Method of Low-cost Titanium Alloy". The Chinese invention patent uses Mo-Fe master alloy powder and titanium powder to be evenly mixed, pressed and then vacuum sintered. The alloy composition is calculated by mass fraction. : Fe: 1.5wt.%, Mo: 2.5wt.%, improve the plasticity and fatigue properties of the alloy, the tensile strength reaches more than 850MPa, the elongation is not less than 15%, and the reduction of area is not less than 20%; however, the price of Mo It is still expensive, so the cost reduction is limited. Only cheap elements such as Fe, Al, Si, Cr, C, O, N and B can achieve the purpose of greatly reducing the cost of titanium alloys.

Contents of the invention

According to one aspect of the present application, a low-cost titanium alloy is provided, which uses Fe and B elements as alloying elements, so that the cost of the titanium alloy is significantly reduced, and at the same time, the tensile strength of the titanium alloy reaches 750MPa ～850MPa, elongation 10-15%, its comprehensive performance can meet the requirements of some engineering fields.

In order to achieve the above object, the application adopts the following technical solutions:

A low-cost titanium alloy, characterized in that the titanium alloy uses titanium as the main element, the α-stable element B and the β-stable element Fe as alloy elements, and the content of each component of the titanium alloy is: Fe: 0.5-5wt .%, B: 0.05-0.2wt.%, the balance is titanium and unavoidable impurities.

Preferably, the content of each component of the titanium alloy is: Fe: 2-5wt.%, B: 0.1-0.2wt.%, and the balance is titanium and unavoidable impurities.

Preferably, the content of each component of the titanium alloy is: Fe: 3-4wt.%, B: 0.1-0.15wt.%, and the balance is titanium and unavoidable impurities.

Preferably, titanium in the titanium alloy is provided by sponge titanium, boron is provided by Fe-B master alloy, and iron is provided by Fe-B master alloy and industrial pure iron.

Preferably, the inevitable impurities in the low-cost titanium alloy include O≤0.07wt.%, C≤0.03wt.%, N≤0.01wt.%, Si≤0.02wt.%, H≤0.004wt.%, The contents of other impurity elements are all ≤0.01wt.%.

According to still another aspect of the present application, a method for preparing a low-cost titanium alloy is provided.

In order to achieve the above object, the application adopts the following technical solutions:

A method for preparing a low-cost titanium alloy, characterized in that the method comprises the steps of:

(1) Calculate the amount of required sponge titanium, Fe-B master alloy and industrial pure iron according to the content of each component of the titanium alloy, and weigh according to the calculation results;

(2) put the weighed titanium sponge, Fe-B master alloy and industrial pure iron into the water-cooled copper crucible of the cold crucible suspension smelting furnace for smelting to obtain an ingot;

(3) making the ingot obtained in step (2) into a bar after being billeted and forged at 50-150° C. above the phase transformation point;

(4) Sampling the rod obtained in step (3) and performing heat treatment to characterize its structure and properties.

Preferably, said step (2) specifically includes:

Put the weighed sponge titanium, Fe-B intermediate alloy and industrial pure iron into the water-cooled copper crucible of the cold crucible suspension melting furnace, vacuumize the furnace body of the cold crucible suspension melting furnace, and then pass high-purity argon gas into it , at high temperature for the first smelting; after the ingot is fully cooled, turn the ingot upside down and put it into a water-cooled copper crucible for re-smelting, repeating this for 3-4 times until.

Preferably, the first smelting at high temperature refers to the first smelting at 1500-1800° C. for 10-20 minutes, and the temperature and time for re-smelting are the same as the first smelting; preferably the first smelting at 1600° C. for 15 minutes.

Preferably, in step (2), high-purity argon gas is introduced after the furnace body is evacuated, and the high-purity argon gas refers to argon gas with a purity of 99.999%, and the input volume is 0.5-0.7×10 ⁵ Pa.

Preferably, the heat treatment described in step (4) refers to heating the bar to 800-850°C for 0.5-2h and air cooling, then air cooling at 400-600°C for 0.5-2h; preferably heating the bar to Keep warm at 810-840°C for 1-1.5h, then air cool, then keep warm at 500°C for 1h, then air cool.

The beneficial effect that this application can produce comprises:

1) A low-cost titanium alloy provided by this application, the content of each component: Fe: 0.5-5wt.%, B: 0.05-0.2wt.%, the balance is titanium and unavoidable impurities; low-cost titanium alloy The unavoidable impurity content is: O ≤ 0.07wt.%, C ≤ 0.03wt.%, N ≤ 0.01wt.%, Si ≤ 0.02wt.%, H ≤ 0.004wt.%, other impurity elements are ≤ 0.01wt. .%, total impurity content ≤ 0.2wt.%.

The titanium alloy provided by this application has uniform alloy composition, fine structure, tensile strength of 750MPa-850MPa, and elongation of 10-15%. The alloy has the advantage of low cost and can replace some more expensive titanium alloys in some fields .

In this application, Fe is a β stable element of titanium alloy, and its market price is low. Adding Fe to β titanium alloy can speed up the aging response speed of the alloy, and the time required to reach the peak aging strength is also shorter; when the Fe content is too much, it is easy to occur Segregation forms "β spots"; adding B element to titanium can effectively refine the as-cast structure and hinder the growth of refined grains in the subsequent processing process, thereby reducing the number of deformation fires and achieving the purpose of reducing costs.

2) The preparation method of a kind of low-cost titanium alloy provided by the application, its preparation raw material adopts sponge titanium, Fe-B master alloy, industrial pure iron; Master alloy cost is as shown in table 1, and Fe-B master alloy cost Lower than the cost of other master alloys, the cost of Fe-B master alloy is shown in Table 2.

Table 1. Costs of several master alloys in recent years

Table 2. Fe-B master alloy composition

Description of drawings

Fig. 1 is the microstructure figure of the low-cost titanium alloy obtained in embodiment 1;

Fig. 2 is the microstructure figure of the low-cost titanium alloy obtained in embodiment 2;

FIG. 3 is a microstructure diagram of the low-cost titanium alloy obtained in Example 3.

detailed description

The present application is described in detail below in conjunction with the examples, but the present application is not limited to these examples.

Unless otherwise specified, the raw materials in the examples of the present application were purchased through commercial channels.

In order to make the purpose, technical solution and advantages of the present application clearer, the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that these descriptions are exemplary only, and are not intended to limit the scope of the present invention.

Example 1

1. The element ratios of the alloy composition design of the present application are shown in Table 3.

2. Proportion the purchased sponge titanium, Fe-B intermediate alloy and industrial pure iron according to the ratio of 1.5kg per ingot, and then put them into the water-cooled copper crucible of the cold crucible suspension melting furnace, vacuumize the furnace body and pass Argon gas with a purity of 99.999% and high-purity argon gas with an amount of 0.5×10 ⁵ Pa were injected, and the alloy was melted for the first time at 1500° C. for 20 minutes.

3. After the ingot is fully cooled, turn the ingot upside down and put it into a water-cooled copper crucible for re-melting to homogenize the alloy composition, and repeat this for 3-4 times.

4. According to the GB/T23605-2009 method for measuring the beta transition temperature of titanium alloys, the phase transition temperature of the obtained alloy was measured.

5. The ingot is forged at 50-150°C above the phase transition point and then made into a bar.

6. After sampling the bar, heat it at 840°C for 1 hour and then air-cool it, then carry out the heat treatment system of holding it at 500°C for 1 hour and then air-cool it.

7. Perform microstructure characterization of the alloy after heat treatment, as shown in Figure 1, and perform mechanical property tests in accordance with the requirements of the national standard GB/T228.1-2010, and see Table 4 for properties.

Table 3. The proportioning composition of alloy in embodiment 1

Table 4. Mechanical properties of rods in Example 1

Example 2

(1) Table 5 shows the element ratios of the alloy composition design of the present application.

(2) Proportion the purchased sponge titanium, Fe-B intermediate alloy, and industrial pure iron according to the ratio of 1.5kg per ingot, and then put them into the water-cooled copper crucible of the cold crucible suspension melting furnace, and vacuumize the furnace body Argon with a purity of 99.999% and high-purity argon with an amount of 0.6×10 ⁵ Pa was introduced, and the alloy was melted for the first time at 1800° C. for 10 minutes.

(3) After the ingot is fully cooled, turn the ingot upside down and put it into a water-cooled copper crucible for re-melting to homogenize the alloy composition, and repeat this process for 3-4 times.

(4) According to the GB/T 23605-2009 method for measuring the β-transition temperature of titanium alloys, the phase transition temperature of the obtained alloy was measured.

(5) The ingot is forged at 50-150°C above the phase transition point and then made into a bar.

(6) After the bar is sampled, it is heat-treated at 810°C for 1 hour and then air-cooled, and then at 500°C for 1 hour and then air-cooled.

(7) Perform microstructure characterization of the alloy after heat treatment, as shown in Figure 2, and perform mechanical property tests in accordance with the requirements of the national standard GB/T228.1-2010, and see Table 6 for properties.

Table 5. Proportioning composition of alloy in embodiment 2

Table 6. Mechanical properties of rods in Example 2

Example 3

(1) Table 7 shows the element ratios of the alloy composition design of the present application.

(2) Proportion the purchased sponge titanium, Fe-B intermediate alloy, and industrial pure iron according to the ratio of 1.5kg per ingot, and then put them into the water-cooled copper crucible of the cold crucible suspension melting furnace, and vacuumize the furnace body Argon gas with a purity of 99.999% and high-purity argon gas with an amount of 0.5×10 ⁵ Pa was introduced, and the alloy was melted for the first time at 1600° C. for 15 minutes.

(3) After the ingot is fully cooled, turn the ingot upside down and put it into a water-cooled copper crucible for re-melting to homogenize the alloy composition, and repeat this process for 3-4 times.

(4) According to the GB/T 23605-2009 method for measuring the β-transition temperature of titanium alloys, the phase transition temperature of the obtained alloy was measured.

(5) The ingot is forged at 50-150°C above the phase transition point and then made into a bar.

(6) After the bar is sampled, it is heat-treated at 810°C for 1 hour and then air-cooled, and then at 500°C for 1 hour and then air-cooled.

(7) Perform microstructural characterization of the alloy after heat treatment, as shown in Figure 3, and perform mechanical performance tests in accordance with the requirements of the national standard GB/T228.1-2010, and see Table 8 for the properties.

Table 7. Proportioning composition of alloy in embodiment 3

Table 8. Mechanical properties of rods in Example 3

The above are only a few embodiments of the application, and do not limit the application in any form. Although the application is disclosed as above with preferred embodiments, it is not intended to limit the application. Any skilled person familiar with this field, Without departing from the scope of the technical solution of the present application, any changes or modifications made using the technical content disclosed above are equivalent to equivalent implementation cases, and all belong to the scope of the technical solution.

Claims (10)

1. a low-cost titanium alloy, it is characterised in that described titanium alloy is with titanium as main element, steady with α stable element B and β Determining element of Fe is alloying element, and each component content of described titanium alloy is: Fe:0.5-5wt.%, B:0.05-0.2wt.%, remaining Amount is titanium and inevitable impurity.

Low-cost titanium alloy the most according to claim 1, it is characterised in that each component content of described titanium alloy is: Fe: 2-5wt.%, B:0.1-0.2wt.%, surplus is titanium and inevitable impurity.

Low-cost titanium alloy the most according to claim 2, it is characterised in that each component content of described titanium alloy is: Fe: 3-4wt.%, B:0.1-0.15wt.%, surplus is titanium and inevitable impurity.

4. according to the low-cost titanium alloy described in any one in claim 1-3, it is characterised in that the titanium in described titanium alloy Being thered is provided by titanium sponge, boron is provided by Fe-B intermediate alloy, and ferrum is provided by Fe-B intermediate alloy and ingot iron.

5. according to the low-cost titanium alloy described in any one in claim 1-3, it is characterised in that described low-cost titanium alloy In inevitably impurity include O≤0.07wt.%, C≤0.03wt.%, N≤0.01wt.%, Si≤0.02wt.%, H≤ 0.004wt.%, other impurity content all≤0.01wt.%.

6. the preparation method of the low-cost titanium alloy as described in any one in claim 1-5, it is characterised in that described Method comprises the steps:

(1) calculate required titanium sponge, Fe-B intermediate alloy and the amount of ingot iron by each component content of described titanium alloy, and press Weigh according to result of calculation；

(2) the water-cooled copper earthenware of cold crucible levitation melting stove put into by titanium sponge, Fe-B intermediate alloy and the ingot iron after weighing Crucible carries out melting, obtains ingot casting；

(3) ingot casting of step (2) gained is made bar after the above 50-150 DEG C of cogging of transformation temperature is forged into；

(4) bar to step (3) gained carries out the sign of structure and performance after carrying out heat treatment after sampling.

The preparation method of low-cost titanium alloy the most according to claim 6, it is characterised in that described step (2) is specifically wrapped Include:

The water jacketed copper crucible of cold crucible levitation melting stove put into by titanium sponge, Fe-B intermediate alloy and ingot iron after weighing In, it is passed through high-purity argon gas after the body of heater evacuation to described cold crucible levitation melting stove, at high temperature carries out pill heat；Wait After ingot casting is sufficiently cool, ingot casting turned upside down is put into water jacketed copper crucible carries out melting again, after 3-4 time be the most repeatedly Only.

The preparation method of low-cost titanium alloy the most according to claim 7, it is characterised in that described at high temperature carry out head Secondary melting, refers to carry out the pill heat of 10-20min when 1500-1800 DEG C, again the temperature and time of melting with melt first Refine identical；At 1600 DEG C, preferably carry out the pill heat of 15min.

9. according to the preparation method of the low-cost titanium alloy described in claim 6 or 7, it is characterised in that in step (2), to stove Being passed through high-purity argon gas after body evacuation, described high-purity argon gas refers to the argon that purity is 99.999%, intake be 0.5-0.7 × 10⁵Pa。

10. according to the preparation method of the low-cost titanium alloy described in claim 6 or 7 or 8, it is characterised in that institute in step (4) The heat treatment stated, refers to bar is heated to air cooling after 800-850 DEG C of insulation 0.5-2h, then carries out 400-600 DEG C of insulation 0.5- Air cooling after 2h；Preferably bar is heated to air cooling after 810-840 DEG C of insulation 1-1.5h, then carries out air cooling after 500 DEG C of insulation 1h.