The heat expansion shape method of alloy special-shaped titanium looping mill rolling spare
Technical field
The present invention relates to a kind of expanding method of ring, particularly related to the heat expansion shape method of alloy special-shaped titanium looping mill rolling spare.
Background technology
After alloy special-shaped titanium looping mill rolling spare (referring to that the longitudinal section is the looping mill rolling spare of non-rectangular cross-section) adopted looping mill rolling, owing to receive the influence of rolling mill practice and equipment limitation, its dimensional accuracy was generally not high; Only under the situation that the special-shaped ring shape of rolling piece is more satisfactory and equipment performance is more excellent; Its dimensional accuracy just can reach 3 ‰ of corresponding size~5 ‰ (3/1000ths to 5/1000ths); And the special-shaped ring rolled piece after rolling is because stress is bigger, if in the following process operation, control defectives such as bad easy generation warpage, distortion even cracking.
On February 18th, 2009, disclosed Chinese invention patent specification CN 101367104A disclosed a kind of turbine generator guard ring external fluid infusion hydraulic pressure expanding and reinforcing process; This process is through the peripheral hardware high-pressure pump and make the highly pressurised liquid of its generation pass through the passage in the high pressure cylinder; Inject fixing last prod cast and the mobile following prod cast and the enclosure space of retaining ring formation via the passage that subtracts in the power post in the mould part then; Make retaining ring that plastic deformation take place under the effect of fluid pressure and come the bulging retaining ring; The purpose that strengthen retaining ring to reach, improves the retaining ring forming accuracy can find out that from this patent specification accompanying drawing said retaining ring is the rectangle ring.This method is owing to be to lean on liquid to contact cold expanding shape rectangle ring with the flexibility of the inner peripheral surface of ring; Therefore; Can only be fit to the little material of some resistances of deformation, it mainly acts on is to strengthen ring, and for example titanium alloy and special-shaped ring are then inapplicable for the bigger material of resistance of deformation; And this method for how also discloses through the dimensional accuracy that bulging improves ring in detail; Just generally draw the purpose that can reach raising retaining ring forming accuracy, promptly this method can not solve the low problem of special-shaped ring workpiece measurement precision that exists in the prior art.
Summary of the invention
The technical problem that the present invention will solve provides a kind of heat expansion shape method that adopts the bulging piece to realize alloy special-shaped titanium looping mill rolling spare; This method is carried out bulging through continuous three small deformation amounts to said alloy special-shaped titanium looping mill rolling spare, has obtained the high bulging special-shaped ring rolled piece of dimensional accuracy.
For solving the problems of the technologies described above, the heat expansion shape method of alloy special-shaped titanium looping mill rolling spare according to the invention, its technical scheme may further comprise the steps:
Put into the bulging machine to hot rolling alloy special-shaped titanium looping mill rolling spare cover; Its inner ring surface is enclosed within through being preheating to the outer circumference surface periphery of 260 ℃~320 ℃ bulging piece; The outer circumference surface of said bulging piece has and the inner peripheral surface of the said special-shaped ring rolled piece consistent shape that matches; At this moment, radial slider is in and closes up state;
Starting the bulging machine applies axial tension F to the mandrel slide block and it is moved down vertically and along the endoporus conical surface extruding radial slide block of said radial slider each radial slider is radially spread with moved further; The bulging piece that is contained on the radial slider outer circumference surface radially pushes this looping mill rolling spare from the inner circumferential surface of special-shaped ring rolled piece; The plastic deformation of size expansion of inside and outside footpath and wall thickness reduction takes place in the special-shaped ring rolled piece, accomplishes bulging for the first time; In this bulging process, the bulging temperature of said special-shaped ring rolled piece is 790 ℃~850 ℃, and the bulging time is 14s~19s, and the dwell time is 11s~13s, and the bulging deflection is 0.3%~0.8%;
The bulging machine drives the mandrel slide block and in radial slider, moves up vertically; And the driving radial slider is radially closed up the special-shaped ring rolled piece that makes after the bulging piece breaks away from bulging with moved further; Deflector roll on the workbench of startup bulging machine makes it drive said special-shaped ring rolled piece along 45 ° of central axis rotations, accomplishes the rotation first time of looping mill rolling spare;
By above-mentioned first time bulging operation to carrying out the bulging second time through the special-shaped ring rolled piece behind the bulging for the first time; In this bulging process; The bulging temperature of said special-shaped ring rolled piece is 760 ℃~820 ℃; The bulging time is 14s~19s, and the dwell time is 11s~13s, and the bulging deflection is 0.5%~1%;
By the operation of above-mentioned first time of rotation to carrying out rotation second time through the special-shaped ring rolled piece behind the bulging for the second time, this rotation, said special-shaped ring rolled piece with the first time direction of rotation rotate 45 ° in the same way again;
By above-mentioned first time bulging operation to carrying out bulging for the third time through the special-shaped ring rolled piece behind the bulging for the second time; In this bulging process; The bulging temperature of said special-shaped ring rolled piece is 720 ℃~790 ℃; The bulging time is 18s~25s, and the dwell time is 15s~17s, and the bulging deflection is 0.7%~1%;
After bulging finished, the mandrel slide block that moves up closed up radial slider, took out the special-shaped ring rolled piece behind bulging.
The above-mentioned titanium alloy preferred material trade mark is the titanium alloy of TC4.
The axial tension F that said bulging machine applies the mandrel slide block is calculated as follows definite:
F=ξ×σ
0.2×S
In the formula:
ξ---bulging machine bulge coefficient, the present invention gets 1.26~1.52;
σ
0.2---the yield strength of titanium alloy material (MPa) under the bulging temperature, the TC4 alloy is got 300MPa~450MPa;
Longitudinal section area (the mm of S---special-shaped ring rolled piece
2);
Said looping mill rolling spare calculates by following formula at the bulging size under hot to be confirmed:
D=D
0(1+β
t)+d
In the formula:
D---special-shaped ring rolled piece is through being in the internal diameter size (mm) under hot behind the bulging;
D
0---the special-shaped ring rolled piece is through being in the final products internal diameter size (mm) under the cold conditions behind the bulging;
β
t---the temperature compensation coefficient (%) of special-shaped ring rolled piece under the bulging temperature, the TC4 alloy gets 0.5%~0.9%;
D---the springback capacity (mm) of internal diameter size behind the special-shaped ring rolled piece bulging, the TC4 alloy is got 3mm~5mm.
Adopt the alloy special-shaped titanium looping mill rolling spare of heat expansion shape method bulging according to the invention, its internal diameter size scope is Ф 400mm~Ф 4500mm, and wall thickness is 10mm~200mm, highly is 40mm~750mm.
Compared with prior art, beneficial effect of the present invention is following:
The present invention carries out rigidity through bulging piece on the bulging machine and alloy special-shaped titanium looping mill rolling spare and contacts direct bulging; Can carry out bulging to the bigger difficult wrought titanium alloy material of resistance of deformation, and can obtain needed bulging size and help improving dimensional accuracy.
The present invention carries out bulging through three small deformation amounts; And through selecting suitable technological parameters such as bulging temperature, bulging time and dwell time; Thereby can guarantee that alloy special-shaped titanium looping mill rolling spare can not produce dynamic recrystallization in the bulging process; Can the tissue of special-shaped ring rolled piece not exerted an influence, the spalling phenomenon can not occur, can also make behind each bulging the springback capacity of special-shaped ring rolled piece less; And in the bulging process through rotating 45 ° to said special-shaped ring rolled piece for twice in the same way; The vestige that gap in the time of can eliminating the bulging piece and radially spread bulging between the adjacent bulging piece forms special-shaped ring rolled piece inner peripheral surface, thus help carrying out smoothly and obtaining the higher bulging special-shaped ring rolled piece of dimensional accuracy of bulging process; In whole bulging process; Because the bulging piece is the springback capacity of internal diameter size behind situation of change and the each bulging of measurement ring rolled piece internal diameter size in real time; And in time be sent to measurement data on the display of bulging machine, thereby when bulging the accurate bulging size of control loop rolled piece.In sum, adopt the looping mill rolling spare of the method for the invention bulging can obtain the higher final products size of dimensional accuracy.
In the bulging process, because bulging machine axial tension F that the mandrel slide block is applied is by YIELD STRENGTH (σ under the bulge coefficient (ξ) of bulging machine, the bulging temperature
0.2) and the longitudinal section area (S) of special-shaped ring rolled piece confirm; Therefore; The special-shaped ring rolled piece that can be directed against different bulging machines and different materials, size is confirmed the size of axial tension F; Make that the special-shaped ring rolled piece is stressed in the bulging process more evenly rationally can to guarantee carrying out smoothly of bulging process, avoid exerting oneself excessively causing spalling or the too small motionless phenomenon that expands that causes of exerting oneself takes place.
The hot bulging internal diameter size (D) of said bulging special-shaped ring rolled piece by the special-shaped ring rolled piece through being in the final products internal diameter size (D under the cold conditions behind the bulging
0), the temperature compensation coefficient (β of special-shaped ring rolled piece under the bulging temperature
t) and special-shaped ring rolled piece bulging after the springback capacity (d) of internal diameter size calculate definite; Thereby when bulging, can accurately control the thermal state sizes of special-shaped ring rolled piece, and the high cold conditions size of acquisition dimensional accuracy is the final products size of special-shaped ring rolled piece behind bulging after the cooling of bulging special-shaped ring rolled piece.
The present invention just from the looping mill the alloy special-shaped titanium looping mill rolling spare of roll forming be rolled while hot; Not only its waste heat energy enough satisfies the needs of bulging temperature; And can avoid the cooling of special-shaped ring rolled piece to shrink the phenomenon that back stress further increases, bulging helps before special-shaped ring rolled piece stress increases, reducing the influence of stress to special-shaped ring workpiece measurement precision while hot.Bulging can also reduce the operation that reheats while hot, energy savings with raise labour productivity.And, preheating bulging piece, temperature reduces too fastly in the time of can also avoiding said special-shaped ring rolled piece bulging, influences the bulging temperature parameter.
The alloy special-shaped titanium looping mill rolling spare that with the trade mark is TC4 is an example, and the cold conditions size of this alloy special-shaped ring rolled piece after detecting bulging is the final products sizes, has reached 1 ‰ of corresponding size~2 ‰; Through detecting the interior tissue of this special-shaped ring rolled piece, any variation does not take place, and do not have defectives such as distortion, warpage.
Description of drawings
Below in conjunction with the accompanying drawing and the specific embodiment the present invention is done further explain.
Fig. 1 is the profilograph of hot rolling special-shaped ring rolled piece along its center line.
Fig. 2 is the structure diagram of bulging machine.
Fig. 3 is the installation sketch map of hot rolling special-shaped ring rolled piece.
Fig. 4 is the heat expansion shape process sketch map of hot rolling special-shaped ring rolled piece.
Fig. 5 is the sketch map of the special-shaped ring rolled piece behind the bulging piece disengaging bulging.
The specific embodiment
The heat expansion shape method of the described alloy special-shaped titanium of embodiment of the present invention looping mill rolling spare need provide equipment such as bulging machine, manipulator.Be that the titanium alloy of TC4 is the specific embodiment that example specifies this method with China's material trademark below:
The main chemical elements content (percentage by weight) of this alloy is: contain Al amount 5.50~6.80%, V content 3.50~4.50%, contain Fe amount≤0.30%, C content≤0.10%, contain N amount≤0.05%, contain H amount≤0.015%, contain O amount≤0.20%, other elements add up to≤0.30, surplus is Ti.
The structure diagram of bulging machine that is used for the said heat expansion shape of embodiment of the present invention method is as shown in Figure 2, and this bulging machine mainly is made up of mandrel slide block 1, radial slider 2, bulging piece 3, workbench 4 and guide rail 5.Mandrel slide block 1 is conical and is sleeved in the radial slider 2 and cooperates with the taper inner peripheral surface of radial slider 2, and mandrel slide block 1 can be driven by the hydraulic cylinder of bulging machine and in radial slider 2, move up and down vertically and extruding radial slide block 2; Radial slider 2 is installed on the guide rail 5 of bulging machine and can radially moves around along guide rail 5; Radial slider 2 is overlooked direction from Fig. 2 and is seen it is 12 secter pat shapes of separating; Be installed with bulging piece 3 on the outer circumference surface of each secter pat respectively, can form a toroidal with bulging piece 3 when each secter pat closes up; When mandrel slide block 1 moves down in radial slider 2 vertically, can make each radial slider 2 radially make bulging piece 3 reach the purpose of bulging ring with moved further diffusion, the bulging machine can drive each radial slider 2 and radially closes up the ring that makes after bulging piece 3 breaks away from bulgings with moved further when mandrel slide block 1 moves up in radial slider 2 vertically; In addition, on the workbench 4 of this bulging machine, can drive the deflector roll (not shown) of ring in addition in this workbench upper edge central axis rotation.
This alloy is following from being rolled into the processing step that carries out heat expansion shape behind the special-shaped ring rolled piece:
Step 1: installation.
As shown in Figure 3; Earlier be preheating to 260 ℃~320 ℃ to the bulging piece 3 on the bulging machine, again just from the looping mill the TC4 alloy special-shaped ring rolled piece 10 as shown in Figure 1 of roll forming overlap threading bulging machine while hot, make its inner ring surface be enclosed within the outer circumference surface periphery of bulging piece 3; The outer circumference surface of bulging piece 3 has and the inner peripheral surface of the special-shaped ring rolled piece 10 consistent shape that matches; Its bottom surface lie in workbench 4 above, at this moment, radial slider 2 is in closes up state.The shipment of workpiece is mainly accomplished through Robot actions during installation.
Step 2: bulging for the first time.
As shown in Figure 4, start the bulging machine its mandrel slide block 1 is axially moved down along it, mandrel slide block 1 radially spreads each radial slider 2 along its taper surface extruding radial slide block 2 in radial slider 2 with moved further; The outer circumference surface of the bulging piece 3 on the radial slider 2 contacts with the inner circumferential surface of special-shaped ring rolled piece 10; And, make special-shaped ring rolled piece 10 from the inner circumferential surface to the external peripheral surface, receive radial compression power from bulging piece 3 along the inner circumferential surface of special-shaped ring rolled piece 10 extruding special-shaped ring rolled piece 10, cause the inner peripheral surface of special-shaped ring rolled piece 10 radially to enlarge; Inside and outside footpath size takes place and enlarges in special-shaped ring rolled piece 10; The plastic deformation of wall thickness reduction, special-shaped ring rolled piece 10 is by bulging piece bulging 3 first time, the axial tension F that the hydraulic cylinder of bulging machine applies mandrel slide block 1 during bulging; The bulging temperature of special-shaped ring rolled piece 10 is 790 ℃~850 ℃; The bulging time is 14s~19s, and the dwell time is 11s~13s, and the bulging deflection of special-shaped ring rolled piece 10 is 0.3%~0.8%.
The said bulging time is the time after special-shaped ring rolled piece 10 is finished to bulging by bulging from the beginning; The said dwell time is meant that special-shaped ring rolled piece 10 is reached by bulging and no longer deforms behind the deflection and remain to the time that bulging finishes always.
Step 3: rotation for the first time.
As shown in Figure 5; Making the bulging machine drive mandrel slide block 1 moves up in radial slider 2 vertically; And driving radial slider 2 is radially closed up the special-shaped ring rolled piece 10 that makes after bulging piece 3 breaks away from bulgings with moved further; Start deflector roll on the workbench 4 of bulging machine and make it drive special-shaped ring rolled piece 10 clockwise or be rotated counterclockwise 45 °, thereby accomplish the rotation first time of special-shaped ring rolled piece 10 at this workbench upper edge central axis.
Step 4: bulging for the second time.
The bulging process of repeating step 1 makes 3 pairs of special-shaped ring rolled pieces of bulging piece 10 carry out the bulging second time; The hydraulic cylinder of bulging machine applies axial tension F to mandrel slide block 1 during bulging; The bulging temperature of special-shaped ring rolled piece 10 is 760 ℃~820 ℃; The bulging time is 14s~19s, and the dwell time is 11s~13s, and the bulging deflection of special-shaped ring rolled piece 10 is 0.5%~1%.
Step 5: rotation for the second time.
Repeating step 3 makes the deflector roll of bulging machine drive special-shaped ring rolled piece 10 and rotates 45 ° in the same way again with direction of rotation for the first time, thereby accomplishes the rotation second time of special-shaped ring rolled piece 10.
Step 6: bulging for the third time.
The bulging process of repeating step 1 makes 3 pairs of special-shaped ring rolled pieces of bulging piece 10 carry out bulging for the third time; The axial tension F that the hydraulic cylinder of bulging machine applies mandrel slide block 1 during bulging; The bulging temperature of special-shaped ring rolled piece 10 is 720 ℃~790 ℃; The bulging time is 18s~25s, and the dwell time is 15s~17s, and the bulging deflection of special-shaped ring rolled piece 10 is 0.7%~1%.
After three times bulging finished, the mandrel slide block 1 that moves up closed up radial slider 2 and makes bulging piece 3 break away from special-shaped ring rolled piece 10, accomplishes the bulging process thereby take out special-shaped ring rolled piece 10 with manipulator.
Special-shaped ring rolled piece 10 is in the bulging process, and said axial tension F is calculated as follows:
F=ξ×σ
0.2×S
In the formula:
ξ---bulging machine bulge coefficient, the present invention gets 1.26~1.52;
σ
0.2---the yield strength of titanium alloy material (MPa) under the bulging temperature, the present invention gets 300MPa~450MPa;
Longitudinal section area (the mm of S---special-shaped ring rolled piece 10
2);
The computational methods of the bulging deflection of said special-shaped ring rolled piece 10 are: bulging deflection=[the middle footpath size of special-shaped ring rolled piece 10 before (the middle footpath size of the preceding special-shaped ring rolled piece 10 of the middle footpath size-bulging of special-shaped ring rolled piece 10 behind the bulging)/bulging] * 100%.
The middle footpath size of said special-shaped ring rolled piece 10=(outside dimension of the internal diameter size of special-shaped ring rolled piece 10+special-shaped ring rolled piece 10) ÷ 2
For guaranteeing that said special-shaped ring rolled piece 10 can access the final size of product requirement behind bulging, special-shaped ring rolled piece 10 calculates by following formula at the bulging size under hot:
D=D
0(1+β
t)+d
In the formula:
D---special-shaped ring rolled piece 10 is through being in the internal diameter size (mm) under hot behind the bulging;
D
0---special-shaped ring rolled piece 10 is through being in the final products internal diameter size (mm) under the cold conditions behind the bulging;
β
t---the temperature compensation coefficient (%) of special-shaped ring rolled piece 10 under the bulging temperature, different for the temperature compensation coefficient of material different under different temperatures, the present invention gets 0.5%~0.9%;
D---the springback capacity (mm) of internal diameter size behind special-shaped ring rolled piece 10 bulgings, the present invention gets 3mm~5mm.
Above-mentioned size has comprised the size of any corresponding point on special-shaped ring rolled piece 10 longitudinal sections, during practical operation, for simplicity, generally only measures the size of the big end surface of special-shaped ring rolled piece 10, and said big end surface is the bottom face of special-shaped ring rolled piece 10 among Fig. 1.
Adopt the alloy special-shaped titanium looping mill rolling spare of said method bulging, its internal diameter size scope is: Ф 400mm~Ф 4500mm, wall thickness are 10mm~200mm, highly are 40mm~750mm.
The present invention is not limited to above-mentioned special-shaped ring rolled piece 10; For the special-shaped ring rolled piece of different cross section as long as correspondingly be processed into the corresponding to shape of shape with the inner peripheral surface of special-shaped ring rolled piece to the outer circumference surface shape of bulging piece 3, but adopt method of the present invention just bulging go out the special-shaped ring rolled piece of different cross section.