CN105363973A - Method for formation of beta-phase titanium alloy multi-step large profiled ring - Google Patents

Abstract

The invention discloses a method for forming a multi-step large-scale special-shaped ring of β-phase titanium alloy. The steps are as follows: firstly, a middle ring billet is assisted by drawing software, and the middle ring billet is put into a ring rolling mill for rolling. During rolling, Raise the working table where the intermediate ring blank is located by 5mm to 10mm, so that the main roller first contacts with the lower end of the intermediate ring blank, so as to ensure that the metal material starts to fill the mold cavity from bottom to top, and gradually completes the forming of each step, and then rolls The multi-step large-scale special-shaped ring is bulged. The method can realize multi-step large-scale special-shaped ring parts, and can effectively avoid the phenomenon of biased ribs or cross-string ribs when forming multi-step large-scale special-shaped ring parts, thereby improving the performance of forgings. The method is suitable for the forming of multi-step large special-shaped rings of β-phase titanium alloy.

Description

Forming method of multi-step large-scale special-shaped ring of β-phase titanium alloy

technical field

The invention relates to a method for forming a multi-step large-scale special-shaped ring, in particular to a method for forming a multi-step large-scale special-shaped ring of β-phase titanium alloy.

Background technique

Special-shaped ring forgings are designed according to the contour of the part, which can effectively improve the utilization rate of materials, obtain ideal performance and streamlines that match the contour of the part. However, in reality, the shape of parts is often strange, and it is difficult to design completely according to the outline of the part. It can only be designed as a special-shaped ring forging that is similar to the cross-section of the part and is relatively simple. Compared with the rectangular ring forging, this method uses more materials. Although the rate has increased, the amount of improvement is limited. At present, most of the special-shaped rings formed by rolling are simple special-shaped rings, for example, special-shaped rings with only one, two or three steps. However, for large-scale special-shaped rings with multiple steps (more than three), the cross-sectional changes are complex, and the design requirements for blanks and molds are very high. Few manufacturers at home and abroad can directly form them by rolling.

The Chinese invention patent specification CN102873511A published on January 16, 2013 discloses a method of radial rolling forming of a complex cross-section ring with three steps. After uniformly heating the material section from room temperature to austenite temperature and keeping it warm, it is rounded, upset and die forged to form a pre-forging with concave holes at both ends, and finally a ring for rolling is obtained by punching in the middle of the pre-forging and punching and connecting the skin. After the blank is returned to the furnace to be heated, when the temperature reaches the target temperature and kept warm, it is taken out, put into the radial ring rolling machine for rolling in the closed pass, and after multi-rotation rolling, it is deformed into a specified shape and size with three steps. The ring forgings with complex cross-sections are subjected to normalizing and tempering heat treatment to ensure the mechanical properties, and finally the forgings are cut and processed into finished rings. The three-step ring formed by this method is in plane contact with the mold during the rolling process, so the forming is relatively simple. For complex multi-step special-shaped rings, when this method is used to form, the forming effect will be seriously affected due to the unreasonable design of the blank or the mold, or the unreasonable matching of the blank and the mold during the rolling process.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for forming a multi-step large-scale special-shaped ring of β-phase titanium alloy. The method assists the drawing software to prepare the intermediate ring blank, and controls the rolling process and the bulging process. Forming of β-phase titanium alloy multi-step large-scale special-shaped ring.

In order to solve the above-mentioned technical problems, the forming method of the β-phase titanium alloy multi-step large-scale special-shaped ring according to the present invention, its technical solution includes the following steps:

According to the structural characteristics of β-phase titanium alloy multi-step large-scale special-shaped rings, with the help of drawing software, the forging cross-section is cut equidistantly from the height direction layer by layer, and the cross-sectional area data of multi-step large-scale special-shaped rings is obtained and made into a curve to obtain multi-step large-scale special-shaped The change relationship between the cross-sectional area and height of the ring; then according to the change trend of the cross-sectional area and height of the multi-step large-scale special-shaped ring, and the principle of equal volume, draw the change of the cross-sectional area and height of the intermediate ring blank by drawing points on the drawing software Relationship curve, so that the shape and size of the intermediate ring blank can be obtained;

Take a β-phase titanium alloy bar of a certain specification, heat it to the forging temperature, and then undergo upsetting, punching, and pre-rolling to form a rectangular ring blank; according to the shape and size of the intermediate ring blank, the intermediate ring blank is obtained through film forming;

Put the intermediate ring blank into the core roller of the ring rolling mill, raise the working table where the intermediate ring blank is located by 5mm to 10mm, and release it until the intermediate ring blank is completely bitten in, so that the intermediate ring blank is in a tilted state; drive the main roll Close to the middle ring billet, make the main roller contact with the lower end of the middle ring billet first; start the ring rolling mill for rolling, the metal material starts to fill the mold cavity, and gradually completes the forming of each step from bottom to top. During this process, The intermediate ring billet is restored from the tilted state to the normal state, and special-shaped ring rolling pieces are obtained;

Put the special-shaped ring rolling piece into the bulging machine. The target size of the bulging is based on the inner diameter of the lower end of the multi-step large special-shaped ring piece, and the special-shaped ring rolling piece is bulged. After reaching the target size, keep it for 20s~30s to get more Large shaped ring piece for steps.

The profile of the main roll is made according to the outer diameter profile of a multi-step large special-shaped ring, the height H ₁ of the main roll = H _forging × (1+Φ) + ρ ₁ , where H _forging is a multi-step large special-shaped Ring height, Φ is the thermal shrinkage rate of the material, ρ ₁ is the height compensation amount of the main roller; ρ ₁ is evenly distributed on the upper and lower ends of the main roller.

The profile of the core roll is made according to the inner diameter profile of a multi-step large-scale special-shaped ring, the height of the core roll H ₂ =H _forging ×(1+Φ)+ρ ₂ , where H _forging is a multi-step large-scale special-shaped ring Φ is the thermal shrinkage rate of the material, ρ ₂ is the height compensation of the core roller; ρ ₂ is evenly distributed on the upper and lower ends of the core roller.

The outer diameter R'=R-ε of the special-shaped ring rolling piece, in the formula, R is the outer diameter of the multi-step large-scale special-shaped ring piece, and ε is the amount of subsequent bulging deformation; the inner diameter r' of the special-shaped ring rolling piece= r-ε, where r is the outer diameter of the multi-step large special-shaped ring, and ε is the amount of subsequent bulging deformation.

The target size of the bulge is r ₂ =r ₁ ×(1+Φ)+δ, where r ₁ is the inner diameter of the lower end of the multi-step large shaped ring, Φ is the thermal shrinkage rate of the material, and δ is the springback compensation quantity.

The β-phase titanium alloy is a TB2 alloy, and its heat shrinkage rate Φ is 0.6%.

Compared with the prior art, the beneficial effects of the present invention are as follows:

The forming method of the β-phase titanium alloy multi-step large-scale special-shaped ring in the present invention uses drawing software to assist in the design of the intermediate ring blank, so that the cross-sectional area of the intermediate ring blank is basically consistent with the cross-sectional area of the multi-step large-scale special-shaped ring, which overcomes the The multi-step large-scale special-shaped ring has many abrupt changes in cross-section and is difficult to form.

During the rolling process, the working table where the intermediate ring billet is located is raised by 5mm to 10mm, so that the main roller first contacts the lower end of the intermediate billet, so as to ensure that the steps of the multi-step large special-shaped ring are filled smoothly from bottom to top, and there will be no Phenomena such as biased tendons and strings. Compensation amounts of ρ ₁ and ρ ₂ are respectively added to the main roll and the core roll to prevent roll climbing during the rolling of special-shaped rings, resulting in partial ribs or cross ribs. Compared with the multi-step large-scale special-shaped ring, the inner and outer diameters of the rolled special-shaped ring are smaller than ε, leaving a margin for subsequent bulging.

During the bulging process, a springback compensation amount of δ size is left, which ensures the size of the final formed β-phase titanium alloy multi-step large special-shaped ring.

Take the β-phase titanium alloy multi-step large-scale special-shaped ring with the brand name TB2 as an example:

After testing the alloy multi-step large-scale special-shaped ring parts have defects such as partial ribs or string ribs, and the overall dimensions are complete.

After testing the room temperature tensile properties of the alloy multi-step large special-shaped ring, its tensile strength is 1411Mpa ~ 1451Mpa (greater than the 1345Mpa required for use), and its tensile strength is 1056MPa (greater than 1023.3MPa for the design use requirement). The length is 10% (more than 9% of the design requirements).

The test results of the high-temperature tensile endurance test of the alloy multi-step large-scale special-shaped ring parts also meet the technical requirements.

The above test results show that all the performance indicators of the TB2 multi-step large-scale special-shaped ring formed by the forming method meet the requirements.

Description of drawings

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments.

Fig. 1 is a structural schematic diagram of a multi-step large-scale special-shaped ring.

Fig. 2 is the relationship curve of the cross-sectional area-height of the multi-step large-scale special-shaped ring and the intermediate ring blank.

Fig. 3 is a schematic diagram of the first tire membrane forging.

Fig. 4 is a schematic diagram of the second tire film forging.

Fig. 5 is a schematic diagram of the rolling forming process.

Fig. 6 is a structural schematic diagram of a special-shaped ring rolling piece.

detailed description

Implementing the forming method of the β-phase titanium alloy multi-step large-scale special-shaped ring according to the present invention requires the provision of forging heating furnaces, presses, ring rolling machines, bulging machines, manipulators and other equipment. The specific implementation of the method will be described in detail below by taking the β-phase titanium alloy whose material grade is TB2 in my country as an example:

The main chemical element content (percentage by weight) of the alloy is: 4.7%-5.7% Mo content, 4.7%-5.7% V content, 7.5%-8.5% Cr content, 2.5%-3.5% Al content, Fe content ≤ 0.30%, C content ≤ 0.05, N content ≤ 0.04%, H content 0.015%, O content 0.15%, the balance being Ti, and the sum of other elements ≤ 0.40.

The steps of this method are as follows:

Step 1: Prepare intermediate ring blank

As shown in Figure 1, according to the structural characteristics of the β-phase titanium alloy multi-step large-scale special-shaped ring 1, the cross-section of the forging is cut equidistantly from the height direction layer by layer with the help of drawing software, and the cross-sectional area data of the multi-step large-scale special-shaped ring 1 is obtained and produced. curve 2, as shown in Figure 2, so as to obtain the variation relationship between the cross-sectional area and height of the multi-step large-scale special-shaped ring piece 1; Points are drawn on the drawing software, and the relationship curve 3 between the cross-sectional area and the height of the intermediate ring blank 5 is drawn, so that the shape and size of the intermediate ring blank 5 can be obtained.

Take a β-phase titanium alloy bar of a certain specification, heat it to the forging temperature, and then undergo upsetting, punching, and pre-rolling to form a rectangular ring billet 4; put the rectangular ring billet 4 into the tire film 7, as shown in Figure 3 , take the small punch 8 to squeeze the rectangular ring blank 4 for the first time; then take out the punch 8, put the cushion block 10 at the bottom of the tire membrane 7, as shown in Figure 4, take the replacement big punch 9 to carry out Extruding for the second time, the intermediate ring blank 5 is obtained.

Step 2: Roll Forming

Insert the intermediate ring blank 5 into the core roll 12 of the ring rolling mill. The profile of the core roll 12 is made according to the inner diameter profile of the multi-step large-scale special-shaped ring 1. The height H ₂ of the core roll 12 = H _forging × (1+ Φ)+ρ ₂ , (where, H _forging is the height of the multi-step large shaped ring, Φ is the thermal shrinkage rate of the material, ρ ₂ is the height compensation of the core roll); ρ ₂ is evenly distributed on the top and bottom of the core roll 12 Both ends; raise the working table where the middle ring blank 5 is located by 5 mm to 10 mm until the middle ring blank 5 is completely bitten in and release it, so that the middle ring blank 5 is in a tilted state; drive the main roller 11 close to the middle ring blank 5, The main roll 11 is first contacted with the lower end of the intermediate ring blank 5; the profile of the main roll 11 is made according to the outer diameter profile of the multi-step large-scale special-shaped ring 1, and the height H ₁ of the main roll 11 = H _forging × (1+ Φ)+ρ ₁ , (where, H _forging is the height of the multi-step large-scale special-shaped ring, Φ is the heat shrinkage rate of the material, ρ ₁ is the height compensation amount of the main roll); ρ ₁ is evenly distributed on the top and bottom of the main roll 11 ends. Start the ring rolling mill and carry out rolling, the metal material begins to fill the mold cavity, and the forming of each step is gradually completed from bottom to top. 6. Outer diameter R' of special-shaped ring rolling piece 6 = R-ε, (in the formula, R is the outer diameter of multi-step large-scale special-shaped ring piece, and ε is the amount of subsequent bulging deformation), and the inner diameter of special-shaped ring rolling piece r' =r-ε, (where r is the outer diameter of the multi-step large-scale special-shaped ring, and ε is the amount of subsequent bulging deformation).

Step 3: Bulging Forming

Put the special-shaped ring rolling piece 6 into the bulging machine. The target size of the bulging is based on the inner diameter of the lower end of the multi-step large special-shaped ring piece 1, and carry out bulging on the special-shaped ring rolling piece 6. After reaching the target size, keep it for 20s~30s , to obtain a multi-step large-scale special-shaped ring piece 1 . The target size of the bulge r ₂ =r ₁ ×(1+Φ)+δ, (where r ₁ is the inner diameter of the lower end of the multi-step large-scale special-shaped ring, Φ is the thermal shrinkage rate of the material, and δ is the springback compensation amount).

The aforementioned β-phase titanium alloy is a TB2 alloy, and its heat shrinkage rate Φ is 0.6%.

Claims (6)

1. A method for forming a multi-step large-scale special-shaped ring of β-phase titanium alloy, characterized in that, comprising the following steps: According to the structural characteristics of β-phase titanium alloy multi-step large-scale special-shaped rings, with the help of drawing software, the forging cross-section is cut equidistantly from the height direction layer by layer, and the cross-sectional area data of multi-step large-scale special-shaped rings is obtained and made into a curve to obtain multi-step large-scale special-shaped The change relationship between the cross-sectional area and height of the ring; then according to the change trend of the cross-sectional area and height of the multi-step large-scale special-shaped ring, and the principle of equal volume, draw the change of the cross-sectional area and height of the intermediate ring blank by drawing points on the drawing software Relationship curve, so that the shape and size of the intermediate ring blank can be obtained; Take a β-phase titanium alloy bar of a certain specification, heat it to the forging temperature, and then undergo upsetting, punching, and pre-rolling to form a rectangular ring blank; according to the shape and size of the intermediate ring blank, the intermediate ring blank is obtained through film forming; Put the intermediate ring blank into the core roller of the ring rolling mill, raise the working table where the intermediate ring blank is located by 5mm to 10mm, and release it until the intermediate ring blank is completely bitten in, so that the intermediate ring blank is in a tilted state; drive the main roll Close to the middle ring billet, make the main roller contact with the lower end of the middle ring billet first; start the ring rolling mill for rolling, the metal material starts to fill the mold cavity, and gradually completes the forming of each step from bottom to top. During this process, The intermediate ring billet is restored from the tilted state to the normal state, and special-shaped ring rolling pieces are obtained; Put the special-shaped ring rolling piece into the bulging machine. The target size of the bulging is based on the inner diameter of the lower end of the multi-step large special-shaped ring piece, and the special-shaped ring rolling piece is bulged. After reaching the target size, keep it for 20s~30s to get more Large shaped ring piece for steps. 2. The method for forming a multi-step large shaped ring of β-phase titanium alloy according to claim 1, wherein the β-phase titanium alloy is a TB2 alloy, and its heat shrinkage rate Φ is 0.6%. 3. The forming method of the β-phase titanium alloy multi-step large-scale special-shaped ring according to claim 1 or 2, wherein the profile of the main roll is made according to the outer diameter profile of the multi-step large-scale special-shaped ring, The height of the main roll H ₁ =H _forging ×(1+Φ)+ρ ₁ , where, H _forging is the height of the multi-step large special-shaped ring, Φ is the heat shrinkage rate of the material, and ρ ₁ is the height compensation amount of the main roll ; ρ ₁ evenly distributed in the upper and lower ends of the main roller. 4. The forming method of the multi-step large-scale special-shaped ring of β-phase titanium alloy according to claim 1 or 2, wherein the profile of the core roll is made according to the internal diameter profile of the multi-step large-scale special-shaped ring, and the core Roller height H ₂ =H _forging ×(1+Φ)+ρ ₂ , where H _forging is the height of multi-step large shaped ring, Φ is the heat shrinkage rate of the material, and ρ ₂ is the height compensation of the core roll; ρ ₂ is evenly distributed on the upper and lower ends of the core roll. 5. The forming method of the multi-step large special-shaped ring of β-phase titanium alloy according to claim 1 or 2, characterized in that, the outer diameter R'=R-ε of the special-shaped ring rolled piece, in the formula, R is The outer diameter of the multi-step large-scale special-shaped ring, ε is the amount of subsequent bulging deformation; the inner diameter of the special-shaped ring rolled piece r'=r-ε, where r is the outer diameter of the multi-step large-scale special-shaped ring, and ε is Subsequent bulging deformation. 6. The method for forming a multi-step large-scale special-shaped ring of β-phase titanium alloy according to claim 1 or 2, characterized in that, the target size of the bulge is r ₂ =r ₁ ×(1+Φ)+δ, In the formula, _r1 is the inner diameter of the lower end of the multi-step large special-shaped ring, Φ is the thermal shrinkage rate of the material, and δ is the springback compensation amount.