Background technology
Elbow is a weak link outstanding in the piping, and the reliability of pipeline is mainly determined by the ability to work of elbow.At present, a high pressure production method commonly used of bending has 3 kinds: pushing, bend and suppress.Pushing is modal production method, yet this process can't realize the shaping with straight end elbow; Bending method can make the wall thickness reduction of pipe, should not the less elbow of production radius of curvature.Supporting the press shaping die method in existing mainly is: the straight tube blank that diameter is equated with elbow is heated to 800 ℃, be placed on the counterdie, put into cushion block at the pipe inner chamber, simultaneously in the pipe two ends, place plug, in order to guarantee the position of cushion block and plug, main rely on manually-operated, after compacting is finished, carried out the ball set round with the inner chamber of steel ball by elbow.Therefore this press shaping die method has the following disadvantages: 1, mold attachment is many, and the compacting preliminary preparation is loaded down with trivial details, and production efficiency is low.2, generally need operating personnel more than two people, and longer in the following working time of hot environment.3, this method is not suitable for the production of the straight end of band elbow yet.
Summary of the invention
The purpose of this invention is to provide that a kind of mould is simple, easy to operate, production efficiency is high, can produce that various bands are directly held and do not bend and horizontal shaping methods with the high pressure elbow of straight end high pressure elbow.The present invention mainly adopts thermal flexure and hot tube reducing shaping.
Concrete grammar is as follows:
1, blanking:, get the circumferential compressed coefficient according to the dimensions of elbow product
, according to different corner dimensions,
Value between 0.05 ~ 0.09, so the pipe external diameter is the elbow nominal diameter
Doubly, wall thickness is identical with elbow.Obtain the physical dimension of pipe, blanking then according to above-mentioned numerical computations.Preferably pipe blanking longitudinal cross-section is trapezoidal, and wherein pipe longitudinal cross-section size calculates by the elbow development size.
2, thermal flexure: after the straight tube blank is heated to austenite structure, place on the die that is preheated to 200 ℃ of-300 ℃ of bending moulds,, make the inclined-plane, two ends upwards when pipe blanking longitudinal cross-section when being trapezoidal.Punch comes downwards to the punch-die closure with the press entablature, suppresses flexural deformation, and its cross section becomes elliptical shape when making the pipe integrally bending.Preferably after the bending mould closure, be ellipse perpendicular to the cross section, shape chamber of axis, long axis of ellipse is 1.2 times of elbow nominal diameter, and minor axis is 0.8 times of elbow nominal diameter; Subside with the punch contact area for fear of the pipe middle part, the bending radius at punch middle part is 1.5-2.0 a times of elbow radius.
3, hot tube reducing shaping: the pipe of preliminarily forming after the bending crouched to be put in the matrix cavity that is preheated to 200 ℃-300 ℃ and the cavity dimension shaping mould identical with the elbow outer wall dimension, and pipe cross section long axis of ellipse is identical with the direction of motion of shaping punch at this moment.Shaping mould is matched moulds up and down, makes pipe produce circumferentially compression, and the oval cross section of pipe is shaped to circular cross-section, and when pipe was filled the shaping mould die cavity, its local deformity just obtained repairing.
The present invention compared with prior art has the following advantages:
1, this method can be used for producing the straight end of band and not with the high pressure elbow of all size of straight end, has remedied the limitation of produced in conventional processes.
2, this method adopts bending and shaping two molds, does not use other annexes, and operation is simple, improved production efficiency.
3, the physical dimension of required shaping dies has realized parametrization in the whole process, has shortened the cycle of mould design and processing.
4, only need 1 ~ 2 operating personnel and do not need to be in the hot environment for a long time in the forming process.
Description of drawings
Fig. 1 partly cuts open the dimensions schematic diagram for elbow master of the present invention looks.
Fig. 2 partly cuts open the dimensions schematic diagram for blank master of the present invention looks.
Fig. 3 is a bending mould user mode schematic perspective view of the present invention.
Fig. 4 is the longitudinal profile schematic diagram after the bending mould closure of the present invention.
Fig. 5 is the A-A view of Fig. 4.
Fig. 6 looks schematic diagram for the pipe master of the present invention after bending.
Fig. 7 is the hot tube reducing shaping mould of a present invention user mode schematic perspective view.
Fig. 8 is the hot tube reducing shaping mould of a segmentation of the present invention user mode schematic perspective view.
The specific embodiment
Example 1
Among Fig. 1, the nominal diameter D=500mm of elbow 1 product, wall thickness t=75mm, elbow radius R=500mm, length l=100mm is directly held in angle of bend α=90 °.Get the circumferential compressed coefficient
=0.08, the pipe external diameter is 540mm, and wall thickness is identical with elbow.This pipe blanking longitudinal cross-section is trapezoidal, and as shown in Figure 2, wherein pipe longitudinal cross-section size calculates by the elbow development size.After the straight tube blank is heated to austenite structure, place on the
die 2 that is preheated to 200 ℃ of bending moulds, make the inclined-plane, two ends upwards, bending mould as shown in Figure 3.
Punch 3 comes downwards to the punch-die closure with the press entablature, suppresses flexural deformation, and its cross section becomes elliptical shape as shown in Figure 6 when making the pipe integrally bending.After the above-mentioned bending mould closure, be oval perpendicular to the cross section, shape chamber of axis, long axis of ellipse a=600mm, minor axis b=400mm; Subside the radius of curvature R in the middle part of the punch for fear of pipe middle part and punch contact area '=1.8R=900mm, the zone of R ' be 45 ° as shown in Figure 4 and Figure 5.The pipe of preliminarily forming after the bending crouched to be put in the matrix cavity that is preheated to 200 ℃ and the cavity dimension shaping mould identical with the elbow outer wall dimension, and pipe cross section long axis of ellipse is identical with the direction of motion of shaping punch, as shown in Figure 7.Shaping mould is matched moulds up and down, makes pipe produce circumferentially compression, and the oval cross section of pipe is shaped to circular cross-section, and when pipe was filled the shaping mould die cavity, its local deformity just obtained repairing.The required elbow of final acquisition.
Example 2
Because the pressure that needs in the shaping process is bigger, considers the restriction of plant produced condition, can use the segmentation shaping methods in shaping process, so just can reduce the requirement to equipment tonnage.Producing nominal diameter D=500mm, wall thickness t=75mm, radius R=500mm, angle [alpha]=90 °, directly holding the straight end elbow of not being with of length l=0 is example.Get the circumferential compressed coefficient
=0.08, the pipe external diameter is 540mm, and wall thickness is identical with elbow.This pipe blanking longitudinal cross-section is trapezoidal, and as shown in Figure 2, wherein pipe longitudinal cross-section size calculates by the elbow development size.The thermal flexure process is identical with parameter with example 1 process, as Fig. 3, Fig. 4, Fig. 5 and shown in Figure 6.The part of the pipe right-hand member 1/3rd of preliminarily forming after the bending crouched be put in the matrix cavity that is preheated to 300 ℃ and the cavity dimension shaping mould identical with the elbow outer wall dimension, shaping mould should be greater than 1/3rd of pipe along the axial length of pipe, the cross section long axis of ellipse is identical with the direction of motion of shaping punch, as shown in Figure 8.Shaping mould is matched moulds up and down, makes the part of pipe right-hand member 1/3rd obtain shaping.Mold lifts, and the part at pipe middle part 1/3rd is put into mould, carries out the middle part shaping; Finish the shaping of left end three/part at last.In this example, the whole shaping power of segmentation shaping force rate is little by about 2/3rds.