阅读说明：本技术 一种900MPa强度级别低成本钛合金材料及其制备方法 (900 MPa-strength-level low-cost titanium alloy material and preparation method thereof ) 是由 张利军 刘娣 吴天栋 周中波 张晨辉 卫娜 刘小花 薛祥义 于 2020-12-30 设计创作，主要内容包括：一种900MPa强度级别低成本钛合金材料及其制备方法,按照质量百分比为：Al：5.0％～7.0％,Fe：5.0％～8.0％,O：0.10％～0.30％,Si,0.01％～0.35％,C：≤0.05％,N：≤0.03％,H：≤0.015％,余量为Ti,进行混料,并压制为电极块；将电极块组焊为长条状电极；将条状电极作为自耗电极进行二次熔炼,获得二次锭；再进行开坯锻造即可。本发明采用低成本的Fe元素代替高成本的V、Mo元素作为合金强化剂,可降低合金制造成本10％至30％,并且制得的低成本钛合金材料的抗拉强度在900MPa～1050MPa、延伸率在10％～15％。(A900 MPa strength-level low-cost titanium alloy material and a preparation method thereof are disclosed, wherein the material comprises the following components in percentage by mass: al: 5.0% -7.0%, Fe: 5.0% -8.0%, O: 0.10-0.30%, Si 0.01-0.35%, C: less than or equal to 0.05 percent, N: less than or equal to 0.03%, H: less than or equal to 0.015 percent and the balance of Ti, mixing and pressing into an electrode block; assembling and welding the electrode blocks into strip-shaped electrodes; carrying out secondary smelting by taking the strip-shaped electrode as a consumable electrode to obtain a secondary ingot; and then cogging and forging. The invention adopts low-cost Fe element to replace high-cost V, Mo element as an alloy reinforcer, can reduce the manufacturing cost of the alloy by 10 to 30 percent, and the prepared low-cost titanium alloy material has the tensile strength of 900 to 1050MPa and the elongation of 10 to 15 percent.)

1. The 900 MPa-strength-level low-cost titanium alloy material is characterized in that the nominal component of the low-cost medium-strength titanium alloy is Ti-6Al-6Fe-0.2O, and the mass percentage is as follows:

Al：5.0％～7.0％；

Fe：5.0％～8.0％；

O：0.10％～0.30％；

Si：0.01％～0.35％；

C：≤0.05％；

N：≤0.03％；

H：≤0.015％；

the balance being Ti;

other elements: the single is less than or equal to 0.10 percent, and the sum is less than or equal to 0.40 percent.

2. A preparation method of a 900 MPa-strength-level low-cost titanium alloy material is characterized by comprising the following steps of:

1) the weight percentages are as follows: al: 5.0% -7.0%, Fe: 5.0% -8.0%, O: 0.10-0.30%, Si 0.01-0.35%, C: less than or equal to 0.05 percent, N: less than or equal to 0.03%, H: less than or equal to 0.015 percent and the balance of Ti, mixing and pressing into an electrode block;

2) assembling and welding the electrode blocks into strip-shaped electrodes;

3) smelting the strip electrode prepared in the step 2) as a consumable electrode to obtain a primary ingot;

4) inverting the primary ingot and performing secondary smelting by using the primary ingot as a consumable electrode to obtain a secondary ingot; cooling to obtain an ingot;

5) and heating the cast ingot at 1000-1200 ℃, and then cogging and forging to obtain the 900 MPa-strength-level low-cost titanium alloy material.

3. The method for preparing a 900MPa strength grade low cost titanium alloy material as claimed in claim 2, wherein in step 2), the electrode blocks are assembled and welded into the strip-shaped electrode by using vacuum plasma welding, argon shield plasma welding or vacuum electron beam welding.

4. The method for preparing the 900MPa strength grade low-cost titanium alloy material according to the claim 2, characterized in that in the step 3) and the step 4), smelting is carried out in a vacuum consumable arc furnace.

5. The method for preparing the 900 MPa-strength-level low-cost titanium alloy material according to claim 2, wherein in the step 3), the smelting current is 5-20 KA, and the smelting voltage is controlled to be 26-40V.

6. The method for preparing the 900MPa strength grade low-cost titanium alloy material according to the claim 2, characterized in that in the step 4), the temperature is cooled to be below 400 ℃.

7. The method for preparing the 900 MPa-strength-level low-cost titanium alloy material according to claim 2, wherein in the step 4), the smelting current is 8-23 KA, and the smelting voltage is controlled to be 26-40V.

8. The method for preparing the 900MPa strength grade low-cost titanium alloy material according to claim 2, characterized by further comprising the following steps:

6) heating the 900 MPa-strength-level low-cost titanium alloy material, and forging the heated material into a bar or a plate blank by multiple fire times;

7) and heating the bar and forging the bar into a forge piece, or heating the plate blank and rolling the plate.

9. The method for preparing the 900MPa strength grade low-cost titanium alloy material according to claim 8, wherein in the step 6), the blank is heated at 900-1100 ℃ and then forged into a bar or a slab for multiple times;

in the step 6), the diameter of the bar is 20-500 mm, and the thickness of the plate blank is 80-200 mm.

10. The method for preparing the 900MPa strength grade low-cost titanium alloy material according to claim 8, wherein in the step 7), the bar is heated at 900-1050 ℃ and then forged into a forge piece, and the slab is heated at 900-1050 ℃ and then rolled into a plate with the thickness of 2-50 mm.

Technical Field

The invention belongs to the field of titanium alloy material manufacturing, and relates to a 900 MPa-strength-level low-cost titanium alloy material and a preparation method thereof.

Background

The titanium alloy material with excellent performance is an ideal metal material for structures used in the aviation, aerospace, ship and weapon industries, and is widely used in the high-end industries of aviation, aerospace and the like. In order to obtain good performance, alloying elements such as Al, Mo, V, Zr, and Nb are generally used in titanium alloys. The cost of the raw materials containing Mo, V, Zr, Nb and other elements is high, so that the cost of the titanium alloy material is high, the application of the titanium alloy material in the industries of ships, weapons, chemical engineering, energy and the like is severely restricted, the price rise of the Al-V intermediate alloy further increases the manufacturing cost by about 20 percent by taking the Ti-6Al-4V titanium alloy which is most widely used at present as an example, and the adverse effect is generated on the large-scale popularization and application of the titanium alloy material.

Therefore, it is necessary to develop a low-cost titanium alloy material. In the related reports, some titanium alloy materials with higher performance and price ratio, such as SP-700, are developed in Japan through reducing the cost of titanium sponge, adopting cheap alloy elements to reduce the cost of alloy raw materials, adopting a low-cost process to reduce the processing cost and the like. A great deal of research and engineering application work is carried out in the aspect of low-cost military titanium alloy in the United states, for example, Timet company develops Timetal 62S low-cost titanium alloy by replacing expensive Al-Mo intermediate alloy with low-cost Al-Fe intermediate alloy, and the cost is reduced by 15 to 20 percent compared with Ti-6Al-4V under the same performance level.

Disclosure of Invention

In order to overcome the problems in the prior art, the invention aims to provide a 900 MPa-strength-level low-cost titanium alloy material and a preparation method thereof.

In order to achieve the purpose, the invention adopts the technical scheme that:

a900 MPa strength level low-cost titanium alloy material comprises the nominal components of Ti-6Al-6Fe-0.2O in percentage by mass:

Al：5.0％～7.0％；

Fe：5.0％～8.0％；

O：0.10％～0.30％；

Si：0.01％～0.35％；

C：≤0.05％；

N：≤0.03％；

H：≤0.015％；

the balance being Ti;

other elements: the single is less than or equal to 0.10 percent, and the sum is less than or equal to 0.40 percent.

A preparation method of a 900 MPa-strength-level low-cost titanium alloy material comprises the following steps:

1) the weight percentages are as follows: al: 5.0% -7.0%, Fe: 5.0% -8.0%, O: 0.10-0.30%, Si 0.01-0.35%, C: less than or equal to 0.05 percent, N: less than or equal to 0.03%, H: less than or equal to 0.015 percent and the balance of Ti, mixing and pressing into an electrode block;

2) assembling and welding the electrode blocks into strip-shaped electrodes;

3) smelting the strip electrode prepared in the step 2) as a consumable electrode to obtain a primary ingot;

4) inverting the primary ingot and performing secondary smelting by using the primary ingot as a consumable electrode to obtain a secondary ingot; cooling to obtain an ingot;

5) and heating the cast ingot at 1000-1200 ℃, and then cogging and forging to obtain the 900 MPa-strength-level low-cost titanium alloy material.

The further improvement of the invention is that in the step 2), the electrode blocks are assembled and welded into the strip-shaped electrodes by adopting vacuum plasma welding, argon protection plasma welding or vacuum electron beam welding.

The further improvement of the invention is that in the step 3) and the step 4), smelting is carried out in a vacuum consumable arc furnace.

The further improvement of the invention is that in the step 3), the smelting current is 5-20 KA, and the smelting voltage is controlled to be 26-40V.

In a further development of the invention, in step 4), the cooling is carried out to below 400 ℃.

The further improvement of the invention is that in the step 4), the smelting current is 8-23 KA, and the smelting voltage is controlled to be 26-40V.

The invention is further improved in that the method also comprises the following steps:

6) heating the 900 MPa-strength-level low-cost titanium alloy material, and forging the heated material into a bar or a plate blank by multiple fire times;

7) and heating the bar and forging the bar into a forge piece, or heating the plate blank and rolling the plate.

The further improvement of the invention is that in the step 6), the blank is heated at 900-1100 ℃ and then forged into a bar or a plate blank by multiple times of fire;

in the step 6), the diameter of the bar is 20-500 mm, and the thickness of the plate blank is 80-200 mm.

The further improvement of the invention is that in the step 7), the bar is heated at 900-1050 ℃ and then forged into a forge piece, and the plate blank is heated at 900-1050 ℃ and then rolled into a plate with the thickness of 2-50 mm.

Compared with the prior art, the invention has the following beneficial effects: the invention adopts low-cost Fe element to replace high-cost V, Mo element as an alloy reinforcer, can reduce the manufacturing cost of the alloy by 10 to 30 percent, and the prepared low-cost titanium alloy material has the tensile strength of 900 to 1050MPa and the elongation of 10 to 15 percent, thereby providing a low-cost titanium alloy material which can be popularized and used in a large range for the industries of ship manufacturing, weapon equipment manufacturing, electronic instrument manufacturing, chemical energy manufacturing and the like in China.

Furthermore, the alloy can be prepared into bars, plates or forgings, and meets the requirements of different industries.

Detailed Description

The present invention is described in further detail below with reference to examples:

the nominal component of the low-cost medium-strength titanium alloy is Ti-6Al-6Fe-0.2O, and the low-cost medium-strength titanium alloy comprises the following components in percentage by mass:

ti: a base (balance);

Al：5.0％～7.0％；

Fe：5.0％～8.0％；

O：0.10％～0.30％；

Si：0.01％～0.35％；

C：≤0.05％；

N：≤0.03％；

H：≤0.015％；

other elements: the single is less than or equal to 0.10 percent, and the sum is less than or equal to 0.40 percent.

The invention provides a 900MPa strength-level low-cost titanium alloy material and a preparation method of a bar, a plate and a forge piece thereof, which comprises the following steps:

1) mixing materials according to the component content, and pressing the materials into an electrode block by using a press machine and a die;

2) adopting vacuum plasma welding, argon protection plasma welding or vacuum electron beam welding to assemble and weld the pressed electrode blocks into strip electrodes;

3) smelting the strip-shaped electrode prepared in the step 2) in a vacuum consumable electric arc furnace by taking the strip-shaped electrode as a consumable electrode to obtain a primary ingot;

4) inverting the primary ingot and performing secondary smelting in a vacuum consumable electrode arc furnace to obtain a secondary ingot;

5) cooling the cast ingot to below 400 ℃ and discharging.

6) Peeling the cast ingot, detecting a flaw, sawing a dead head, and simultaneously sampling to test chemical components.

7) And heating the cast ingot at 1000-1200 ℃ and then cogging and forging.

8) Heating the blank at 900-1100 ℃ and forging the blank by multiple timesDiameter bar, slab with thickness delta 80-delta 200.

9)The method comprises the steps of heating a bar with the diameter at 900-1050 ℃, forging the bar into a forging piece with a required specification shape, heating a plate blank with the thickness of delta 80-delta 200 at 900-1050 ℃, and rolling the plate blank into a plate with the thickness of delta 2-delta 50.

In the step 3), the smelting current is 5-20 KA, and the smelting voltage is controlled to be 26-40V.

In the step 4), the smelting current is 8-23 KA, and the smelting voltage is controlled to be 26-40V.

The following are specific examples.

Example 1

Preparing a 300 kg-grade titanium alloy ingot and a small-size bar material thereof:

(1) material preparation and electrode pressing:

nominal composition: ti-6Al-6Fe-0.2O

According to the component range, 300Kg of first-grade sponge titanium, Fe filings or Ti-Fe intermediate alloy, Al beans, titanium dioxide and the like are selected and mixed, and the mixture is pressed into a single block electrode with the weight of 10Kg by a press machine.

(2) Preparing an electrode:

and welding the pressed electrode blocks into a strip-shaped electrode by adopting a vacuum plasma welding machine.

(3) Preparation of Primary ingot

And (3) smelting the electrode prepared in the last step as a consumable electrode in a vacuum consumable arc furnace to obtain a primary ingot, wherein the smelting current is 5KA, and the smelting voltage is 26-33V.

(4) Preparation of ingot

And inverting the primary ingot and performing secondary smelting in a vacuum consumable electrode arc furnace to obtain a finished product ingot, wherein the smelting current is 8KA, and the smelting voltage is 28-35V.

(5) Cooling down

After the smelting is finished, the ingot is required to be cooled to below 400 ℃ and discharged, and the defects of oxidation and the like of the uncooled ingot after being discharged are avoided.

(6) Peeling, cutting riser and sampling

After the head of the ingot is flatheaded and skinned by a lathe, ultrasonic flaw detection is carried out to determine the position of the riser of the ingot, the riser is sawn, and simultaneously, block-shaped and chip-shaped samples are taken from the head, the upper part, the middle part and the lower part of the ingot for component analysis, and the chemical component analysis results are shown in a table 1-1:

TABLE 1-1 chemical composition of 300kg grade titanium alloy ingot

(7) Cogging of cast ingot

Heating the polished and sawed cast ingot to 1150 ℃, preserving heat for 3 hours, discharging the cast ingot out of the furnace, cogging and forging, performing two-stage upsetting and two-stage drawing:

namely, a bar material with the diameter of 280mm and the length of 560mm is upset to a square with the cross section of 325mm side length and a square billet with the length of 325mm, then the square billet is drawn to a square with the cross section of 255mm side length and a square billet with the length of 520mm, then the square with the cross section of 325mm side length and the square billet with the length of 325mm are upset, and finally the blank with the cross section of 255mm side length and the blank with the length of 520mm is drawn.

(8) Forging of intermediate stock

Heating the blank at 1050 ℃ for 3 hours, discharging and forging:

□ 255 × 520 pull → □ 150 × 1502 hot cut pull → □ 150 × 500;

heating the blank at 1000 ℃ for 2 hours, discharging and forging:

(9) forging large-size rods and wires

Heating the blank at 980 ℃ for 1.5 hours, discharging and forging:

(10) heat treatment and Performance testing

The bars were kept at 850 ℃ for 1.5 hours, and samples were taken for mechanical property testing, as shown in tables 1-2.

Tables 1 to 2Room temperature mechanical property of diameter titanium alloy bar

Example 2

Preparing a 300 kg-grade titanium alloy ingot and a bar thereof:

(1) material preparation and electrode pressing:

nominal composition: ti-6Al-6Fe-0.2O

According to the component range, 300Kg of first-grade sponge titanium, Fe filings or Ti-Fe intermediate alloy, Al beans, titanium dioxide and the like are selected and mixed, and the mixture is pressed into a single block electrode with the weight of 10Kg by a press machine.

(2) Preparing an electrode:

and welding the pressed electrode blocks into a strip-shaped electrode by adopting a vacuum plasma welding machine.

(3) Preparation of Primary ingot

And (3) smelting the electrode prepared in the last step as a consumable electrode in a vacuum consumable arc furnace to obtain a primary ingot, wherein the smelting current is 6KA, and the smelting voltage is 26-33V.

(4) Preparation of ingot

And inverting the primary ingot and performing secondary smelting in a vacuum consumable electrode arc furnace to obtain a finished product ingot, wherein the smelting current is 8KA, and the smelting voltage is 28-35V.

(5) Cooling down

After the smelting is finished, the ingot is required to be cooled to below 400 ℃ and discharged, and the defects of oxidation and the like of the uncooled ingot after being discharged are avoided.

(6) Peeling, cutting riser and sampling

After the head of the ingot is flatheaded and skinned by a lathe, ultrasonic flaw detection is carried out to determine the position of the riser of the ingot, the riser is sawn, and simultaneously, block-shaped and chip-shaped samples are taken from the head, the upper part, the middle part and the lower part of the ingot for component analysis, and the chemical component analysis results are shown in a table 2-1:

TABLE 2-1 chemical composition of 300kg grade titanium alloy ingot

(7) Cogging of cast ingot

Heating the polished and sawed cast ingot to 1150 ℃, preserving heat for 3 hours, discharging the cast ingot out of the furnace, cogging and forging, performing two-stage upsetting and two-stage drawing:

(8) forging of intermediate stock

Heating the blank at 1050 ℃ for 3 hours, discharging and forging:

□ 255 × 520 pull → □ 150 × 1502 hot cut pull → □ 150 × 500;

heating the blank at 1000 ℃ for 2 hours, discharging and forging:

heating the blank at 980 ℃ for 1.5 hours, discharging and forging:

(9) rolling of small-size rods and wires

Heating the blank at 960 ℃ for 1 hour, discharging and rolling:

(10) heat treatment and Performance testing

The bars were kept at 850 ℃ for 1.5 hours, and samples were taken for mechanical property testing, see Table 2-2.

Tables 2 to 2Room temperature mechanical property of diameter titanium alloy bar

Example 3

Preparing 1000 kg-grade titanium alloy ingots and forgings thereof:

(1) material preparation and electrode pressing:

nominal composition: ti-6Al-6Fe-0.2O

According to the component range, 1000Kg of first-grade sponge titanium, Fe filings or Ti-Fe intermediate alloy, Al beans, titanium dioxide and the like are selected and mixed, and the mixture is pressed into a single block electrode with the weight of 50Kg by a press machine.

(2) Preparing an electrode:

and welding the pressed electrode blocks into a strip-shaped electrode by adopting a vacuum plasma welding machine.

(3) Preparation of Primary ingot

And (3) smelting the electrode prepared in the last step as a consumable electrode in a vacuum consumable arc furnace to obtain a primary ingot, wherein the smelting current is 9KA, and the smelting voltage is 28-35V.

(4) Preparation of ingot

And inverting the primary ingot and performing secondary smelting in a vacuum consumable electrode arc furnace to obtain a finished product ingot, wherein the smelting current is 12KA and the smelting voltage is 30-38V.

(5) Cooling down

After the smelting is finished, the ingot is required to be cooled to below 400 ℃ and discharged, and the defects of oxidation and the like of the uncooled ingot after being discharged are avoided.

(6) Peeling, cutting riser and sampling

After the head of the ingot is flatheaded and skinned by a lathe, ultrasonic flaw detection is carried out to determine the position of the riser of the ingot, the riser is sawn, and simultaneously, block-shaped and chip-shaped samples are taken from the head, the upper part, the middle part and the lower part of the ingot for component analysis, and the chemical component analysis results are shown in a table 3-1:

TABLE 3-1 chemical composition of 1000kg grade titanium alloy ingot prepared

(7) Cogging of cast ingot

Heating the polished and sawed cast ingot to 1150 ℃, preserving heat for 5 hours, discharging the cast ingot out of a furnace, cogging and forging, performing two-stage upsetting and two-stage drawing:

(8) forging of intermediate stock

Heating the blank at 1050 ℃ for 4 hours, discharging and forging:

□ 360 × 730 upset → □ 460 × 450 pull → □ 360 × 730 pull → □ 250 × L;

heating the blank at 1000 ℃ for 3 hours, discharging and forging:

(9) rolling of ring forgings

Heating the blank at 980 ℃ for 3 hours, discharging and rolling:

heating the blank at 960 ℃ for 2 hours, discharging and rolling:

(10) heat treatment and Performance testing

The forgings were held at 850 ℃ for 1.5 hours, and samples were taken for mechanical property testing, as shown in Table 3-2.

TABLE 3-2Room temperature mechanical property of standard titanium alloy ring forging

Example 4

3000 kg-level titanium alloy ingot casting and plate preparation:

(1) material preparation and electrode pressing:

nominal composition: ti-6Al-6Fe-0.2O

According to the component range, 3000Kg of first-grade sponge titanium, Fe filings or Ti-Fe intermediate alloy, Al beans, titanium dioxide and the like are selected and mixed, and the mixture is pressed into a single block electrode with the weight of 100Kg by a press machine.

(2) Preparing an electrode:

and welding the pressed electrode blocks into a strip-shaped electrode by adopting a vacuum plasma welding machine.

(3) Preparation of Primary ingot

And (3) smelting the electrode prepared in the last step as a consumable electrode in a vacuum consumable arc furnace to obtain a primary ingot, wherein the smelting current is 20KA, and the smelting voltage is 28-38V.

(4) Preparation of ingot

And inverting the primary ingot and performing secondary smelting in a vacuum consumable electrode arc furnace to obtain a finished product ingot, wherein the smelting current is 23KA and the smelting voltage is 30-40V.

(5) Cooling down

After the smelting is finished, the ingot is required to be cooled to below 400 ℃ and discharged, and the defects of oxidation and the like of the uncooled ingot after being discharged are avoided.

(6) Peeling, cutting riser and sampling

After the head of the ingot is flatheaded and skinned by a lathe, ultrasonic flaw detection is carried out to determine the position of the riser of the ingot, the riser is sawn, and simultaneously, block-shaped and chip-shaped samples are taken from the head, the upper part, the middle part and the lower part of the ingot for component analysis, and the chemical component analysis results are shown in a table 4-1:

TABLE 4-1 chemical composition of 3000kg grade titanium alloy ingot prepared

(7) Cogging of cast ingot

Heating the polished and sawed cast ingot to 1150 ℃, preserving heat for 6 hours, discharging the cast ingot out of the furnace, cogging and forging, performing two-stage upsetting and two-stage drawing:

(8) forging of intermediate stock

Heating the blank at 1050 ℃ for 4 hours, discharging and forging:

□ 360 × 850 → δ 120 × 950 × 950;

(9) rolling of sheet material

Heating the blank at 980 ℃ for 2 hours, discharging and rolling:

δ 120 × 950 × 950 rolling → δ 25 × 950 × 4560 split → δ 25 × 950 × 1100 (fire cut is 4 knots);

heating the blank at 970 ℃ for 0.5 hour, discharging and rolling:

δ 25 × 1100 × 950 rolling → δ 8 × 1100 × 3000;

(10) heat treatment and Performance testing

The samples of the panels were incubated at 850 ℃ for 1 hour for mechanical property testing, see Table 4-2.

TABLE 4-2 delta 8 thickness titanium alloy sheet room temperature mechanical properties