阅读说明：本技术 集成多接管的大型变截面筒体仿形锻造工艺 (Profiling forging process for large variable-section cylinder integrated with multiple connecting pipes ) 是由 沈国劬 毛闯 孙嫘 陈新倬 易泓宇 于 2021-10-18 设计创作，主要内容包括：本发明提供了集成多接管的大型变截面筒体仿形锻造工艺,包括：A、根据筒体零件结构特征设计锻件毛坯；B、将钢锭预处理后镦粗为圆饼状坯料,并在圆饼状坯料上冲中心通孔；C、将圆饼状坯料拔长,得到圆柱状坯料；D、对圆柱状坯料进行圆拔长,将中心通孔成形为阶梯孔；E、在圆柱状坯料表面拔出环带凸肩；F、在环带凸肩上锻造成形多个接管；G、对坯料进行扩孔。本发明先将坯料镦粗,再逐步拔长,逐步成形内部阶梯孔和外部的环带凸肩,坯料的外径逐渐减小,以实现在环带凸肩上成形接管时,环带凸肩及其两端的坯料外径尽可能处于最小尺寸,这样整个坯料的径向尺寸小,可以减小接管成形模具的规格,降低模具制造成本,提高接管的成形质量。(The invention provides a profile forging process for a large variable-section cylinder body integrating multiple connecting pipes, which comprises the following steps of: A. designing a forging blank according to the structural characteristics of the cylinder part; B. pre-treating the steel ingot, upsetting the steel ingot into a round cake-shaped blank, and punching a central through hole on the round cake-shaped blank; C. drawing out the cake-shaped blank to obtain a cylindrical blank; D. carrying out round drawing on the cylindrical blank to form a central through hole into a stepped hole; E. pulling out a shoulder of the ring belt on the surface of the cylindrical blank; F. forging and forming a plurality of connecting pipes on the shoulder of the ring belt; G. and (5) reaming the blank. The blank is upset firstly and then is drawn out gradually to form the inner stepped hole and the outer annular shoulder gradually, and the outer diameter of the blank is reduced gradually, so that when the connecting pipe is formed on the annular shoulder, the annular shoulder and the outer diameters of the blanks at the two ends of the annular shoulder are as minimum as possible, the radial size of the whole blank is small, the specification of a connecting pipe forming die can be reduced, the die manufacturing cost is reduced, and the forming quality of the connecting pipe is improved.)

1. A profile forging process for a large-scale variable-section cylinder body integrated with multiple connecting pipes is characterized by comprising

A. Designing a forging blank according to the structural characteristics of the cylinder part, wherein the forging blank comprises a flange section (1), a connecting pipe (2) arranged on the outer wall of the flange section (1) and a cylinder section (3) positioned at one end of the flange section (1); the outer diameter of the flange section (1) is D1, and the inner diameter is D1; the cylinder section (3) has an outer diameter D2 and an inner diameter D2;

B. pre-treating a steel ingot, upsetting the steel ingot into a round cake-shaped blank, punching a central through hole on the round cake-shaped blank, wherein the outer diameter of the round cake-shaped blank is D3;

C. drawing out the round cake-shaped blank to obtain a cylindrical blank, wherein the outer diameter of the cylindrical blank is D4, and D4 is less than D3;

D. circularly drawing a cylindrical blank, forming a central through hole into a stepped hole, wherein the diameter of a small hole section of the stepped hole is D6, the diameter of a large hole section of the stepped hole is D5, the outer diameter of the cylindrical blank is D5, and D5 is less than D4;

E. drawing a ring belt shoulder (4) on the surface of the cylindrical blank, wherein the outer diameter of the blank on two sides of the ring belt shoulder (4) is D6, D6 is more than D5, and D6²-d6²＝λ(D1²-d1²) Wherein λ is a coefficient of pore-enlarging dressing;

F. forging and forming a plurality of connecting pipes (2) on the annular belt shoulder (4), and directly forging the connecting pipes (2) to the designed size; the cylinder body stepped section is pulled out from the outer wall of the large hole section of the stepped hole, and the outer diameter of the cylinder body stepped section is D7 or D7²-d5²＝γ(D2²-d2²) And gamma is the coefficient of the reaming dressing;

G. the blank is reamed so that the diameter of the small hole section of the stepped hole is d1 and the diameter of the large hole section is d 2.

2. The process for forging the large-scale variable-section cylinder with integrated multi-adapter tube according to claim 1, wherein: in the step B, the steel ingot pretreatment process comprises the following steps: upsetting the steel ingot with the as-cast structure, drawing out the steel ingot after upsetting, wherein the upsetting and drawing-out times are at least 1 time.

3. The process for forging the large-scale variable-section cylinder with integrated multi-adapter tube according to claim 1, wherein: and step B, outwards protruding two end faces of the cake-shaped blank.

4. The process for forging the large-scale variable-section cylinder with integrated multi-joint pipe according to claim 1 or 3, wherein: and step C, enabling a mandrel to penetrate through the central through hole, enabling the diameter of the mandrel to be smaller than that of the central through hole, and then utilizing the upper flat anvil and the lower V-shaped anvil to carry out circular drawing.

5. The process for forging the large-scale variable-section cylinder with integrated multi-adapter tube according to claim 1, wherein: in the step D, a step-shaped bar is placed into the central through hole, the diameter of a thicker section of the step-shaped bar is D5, the diameter of a thinner section of the step-shaped bar is D6, D5-D6 is D2-D1, and the axial position of the step-shaped bar satisfies the following conditions: the weight of the blank corresponding to the thicker section of the step-shaped horse bar is matched with the weight of the blank of the cylinder section (3), and the weight of the blank corresponding to the thinner section of the step-shaped horse bar is matched with the weight of the blank of the flange section (1); and (3) carrying out round drawing by utilizing the upper flat anvil and the lower V-shaped anvil, reducing the outer diameter of the cylindrical blank from D4 to D5, and simultaneously contracting a thinner section of a corresponding central through hole of the step bar to be attached to the step bar.

6. The process for forging the large-scale variable-section cylinder with integrated multi-adapter tube according to claim 5, wherein: and step E, the step bumper is positioned in the stepped hole, the upper flat anvil and the lower V-shaped anvil are utilized to pull out the annular shoulder (4) on the surface of the cylindrical blank, the axial length of the annular shoulder (4) is greater than the designed outer diameter of the connecting pipe (2), and the height of the annular shoulder (4) is smaller than the designed height of the connecting pipe (2).

7. The process for forging large-scale variable-section cylinder body with integrated multi-joint pipe according to claim 1, 5 or 6, wherein: in the step F, the forging process of the connecting pipe (2) comprises the following steps: the blank is vertically placed, forging dies are arranged above and below the annular shoulder (4), the forging dies are sleeved on the blank at two ends of the annular shoulder (4), a press applies pressure to the forging dies, the pressure direction is the axial direction of the blank, the forging dies axially move under the guiding action of the blank at two ends of the annular shoulder (4) and extrude the annular shoulder (4), and the connecting pipe (2) is obtained.

8. The process for forging the large-scale variable-section cylinder with the integrated multi-joint pipe according to claim 7, wherein: the connecting pipe (2) is forged and formed firstly, and then the stepped section of the cylinder body is pulled out from the outer wall of the large hole section of the stepped hole.

9. The process for forging large-scale variable-section cylinder body with integrated multi-joint pipe according to claim 1, 5 or 6, wherein: in the step F, the process of pulling out the barrel stepped section from the outer wall of the stepped hole large hole section comprises the following steps: and putting a step bar into the stepped hole, wherein the diameter of a thicker section of the step bar is d5, the diameter of a thinner section of the step bar is d6, and the step section of the cylinder body is pulled out by utilizing an upper flat anvil and a lower V-shaped anvil.

10. The process for forging large-scale variable-section cylinder body with integrated multi-joint pipe according to claim 1, 5 or 6, wherein: step G, placing a step horse bar at the top of the stepped hole, wherein the outer diameter of the step horse bar is smaller than the diameter of the stepped hole, the height of the step surface of the step horse bar is equal to d2-d1, the step surface of the step horse bar is attached to the step surface of the stepped hole, and two ends of the step horse bar are erected on a horse frame; placing a hole-expanding upper anvil (5) at the top of the outer wall of the blank, wherein a first pressing surface, a groove, a second pressing surface and a third pressing surface are sequentially arranged at the bottom of the hole-expanding upper anvil (5), the first pressing surface and the second pressing surface are attached to the outer wall of the blank at two sides of a connecting pipe (2), the connecting pipe (2) is positioned in the groove, and a distance is reserved between the outer end of the connecting pipe (2) and the bottom of the groove; the third pressing surface is attached to the outer wall of the stepped section of the cylinder body; and pressing down the upper reaming anvil (5) to realize reaming.

Technical Field

The invention relates to the technical field of integral forging of large-sized cylinders, in particular to a profiling forging process of a large-sized variable cross-section cylinder integrated with multiple connecting pipes.

Background

The invention relates to a variable cross-section cylinder which is a core component of a nuclear reactor pressure vessel, and the structure of the variable cross-section cylinder comprises a flange section 1, a connecting pipe section and a cylinder section 3, wherein the outer wall of the connecting pipe section is provided with a plurality of uniformly or non-uniformly distributed connecting pipes 2, and as shown in fig. 1 and 2, when an angle alpha is equal to an angle beta, the connecting pipes 2 are uniformly distributed at an angle; when alpha is not equal to beta, the connecting pipe 2 is in non-uniform angle distribution. The side wall of the flange section 1 is thick, the side wall of the cylinder section 3 is thin, steps are arranged on an inner hole and an outer circle, a plurality of evenly or unevenly distributed connecting pipes 2 are integrated on the outer circle of the flange section, the outline size of the cylinder body exceeds phi 5m multiplied by 5m, and the cylinder body belongs to an ultra-large special-shaped cylinder body.

In the disclosed forging technology, a large-sized integrated cylinder body with a complicated structure is disclosed, and the integral forging forming technology for the cylinder body is very few.

CN105033154A discloses an integral forging method of an integrated pipe joint section with a pipe joint and a flange, which designs the size of a blank on the basis of determining the characteristic size of the integrated pipe joint section; locally upsetting and punching a steel ingot into a hollow blank with a central ring belt; prepressing the concave gear by a specially manufactured triangular anvil to finish the formation of the connecting pipe boss; reaming by using a door-shaped hammer head and a feed bar to obtain a blank forging; then, the blank is roughly machined, turned over to form a pipe nozzle, and finally, finish machining is carried out to obtain an integrated pipe connecting section finished product. Compared with the structure of the integrated cylinder body of the invention which lacks a cylinder body section 3, the integrated joint pipe section blank forging piece of the method has the advantages of more complex structure, larger size and larger forging difficulty. Due to the extremely complex structure, the blank making method of the key step in the forging process is of great importance, and the feasibility of the profiling forging and the accuracy of the dimension control are concerned, and the content is not described in detail in the method.

CN110090914A discloses an integral forging forming method for a flange connecting pipe section of a reactor pressure vessel cylinder, the flange connecting pipe section of the cylinder has no obvious variable cross-section characteristic and the structural complexity is not the same as that of the integrated cylinder body.

CN108705023A discloses a profiling forging process of an integrated pipe joint segment forging, which forges a blank into a cylinder blank with a raised belt; arranging an internal supporting structure at a position corresponding to the barrel blank convex belt, and forming a nozzle blank on the convex belt by using a nozzle forming anvil; the nozzle is formed on the basis of the nozzle blank. The nozzle is formed by selecting the variable cross-section cylinder after forging, although the position and the angle of a nozzle blank can be prevented from changing, the size and the specification of the cylinder after reaming are overlarge, the specification of a die required by forming the nozzle is naturally large, the traditional enveloping or semi-enveloping forging method cannot forge, and the operation difficulty and the manufacturing cost are increased.

The invention application No. 201210236488.9 discloses a forming method and a forming device for a pipe structure having a nozzle boss, which is obtained by directly pressing a cylinder to a nipple, and which is suitable only for small-sized equipment.

Disclosure of Invention

The invention aims to solve the technical problem of providing a large variable-section cylinder profile forging process integrating multiple connecting pipes, solving the problem of full-profile forging forming of an integrated cylinder with a complex structure under extreme conditions, greatly improving the material utilization rate and breaking through the limitation that the traditional enveloping or semi-enveloping forging method cannot forge due to overweight of steel ingots.

The technical scheme adopted by the invention for solving the technical problems is as follows: a profiling forging process for a large-scale variable-section cylinder integrated with multiple connecting pipes comprises

A. Designing a forging blank according to the structural characteristics of the cylinder part, wherein the forging blank comprises a flange section, a connecting pipe arranged on the outer wall of the flange section and a cylinder section positioned at one end of the flange section; the outer diameter of the flange section is D1, and the inner diameter is D1; the cylinder section has an outer diameter D2 and an inner diameter D2;

B. pre-treating a steel ingot, upsetting the steel ingot into a round cake-shaped blank, punching a central through hole on the round cake-shaped blank, wherein the outer diameter of the round cake-shaped blank is D3;

C. drawing out the round cake-shaped blank to obtain a cylindrical blank, wherein the outer diameter of the cylindrical blank is D4, and D4 is less than D3;

D. circularly drawing a cylindrical blank, forming a central through hole into a stepped hole, wherein the diameter of a small hole section of the stepped hole is D6, the diameter of a large hole section of the stepped hole is D5, the outer diameter of the cylindrical blank is D5, and D5 is less than D4;

E. drawing a ring belt shoulder on the surface of the cylindrical blank, wherein the outer diameter of the blank on two sides of the ring belt shoulder is D6, D6 is more than D5, and D6²-d6²λ, where λ is the reaming dressing coefficient;

F. forging and forming a plurality of connecting pipes on the shoulder of the ring belt, and directly forging the connecting pipes to the designed size; the cylinder body stepped section is pulled out from the outer wall of the large hole section of the stepped hole, and the outer diameter of the cylinder body stepped section is D7 or D7²-d5²Gamma is the coefficient of the reaming dressing;

G. the blank is reamed so that the diameter of the small hole section of the stepped hole is d1 and the diameter of the large hole section is d 2.

Further, in the step B, the steel ingot pretreatment process comprises the following steps: upsetting the steel ingot with the as-cast structure, drawing out the steel ingot after upsetting, wherein the upsetting and drawing-out times are at least 1 time.

Further, in the step B, two end faces of the cake-shaped blank are protruded outwards.

And step C, a mandrel penetrates through the central through hole, the diameter of the mandrel is matched with that of the central through hole, and circular drawing is carried out by utilizing the upper flat anvil and the lower V-shaped anvil.

Further, in step D, a step-shaped bar is placed in the central through hole, the diameter of the thicker section of the step-shaped bar is D5, the diameter of the thinner section of the step-shaped bar is D6, and D5-D6-D2-D1, and the axial position of the step-shaped bar satisfies the following conditions: the weight of the blank corresponding to the thicker section of the step horse bar is matched with that of the blank of the cylinder section, and the weight of the blank corresponding to the thinner section of the step horse bar is matched with that of the flange section; and (3) carrying out round drawing by utilizing the upper flat anvil and the lower V-shaped anvil, reducing the outer diameter of the cylindrical blank from D4 to D5, and simultaneously contracting a thinner section of a corresponding central through hole of the step bar to be attached to the step bar.

Furthermore, in the step E, the step bumper is positioned in the stepped hole, the upper flat anvil and the lower V-shaped anvil are utilized to pull out the shoulder of the ring belt on the surface of the cylindrical blank, the axial length of the shoulder of the ring belt is greater than the designed outer diameter of the connecting pipe, and the height of the shoulder of the ring belt is smaller than the designed height of the connecting pipe.

Further, in step F, the forging process of the adapter tube is as follows: the blank is vertically placed, forging dies are arranged above and below the shoulder of the girdle and sleeved on the blank at two ends of the shoulder of the girdle, a press applies pressure to the forging dies, the pressure direction is the axial direction of the blank, and the forging dies axially move under the guiding action of the blank at two ends of the shoulder of the girdle and extrude the shoulder of the girdle to obtain the connecting pipe.

Further, the connecting pipe is forged and formed, and then the stepped section of the cylinder body is pulled out from the outer wall of the large hole section of the stepped hole.

Further, in the step F, the process of pulling out the barrel step section from the outer wall of the step hole large hole section is as follows: and putting a step bar into the stepped hole, wherein the diameter of a thicker section of the step bar is d5, the diameter of a thinner section of the step bar is d6, and the step section of the cylinder body is pulled out by utilizing an upper flat anvil and a lower V-shaped anvil.

Step G, placing a step bar on the top of the stepped hole, wherein the outer diameter of the step bar is smaller than the diameter of the stepped hole, the height of the step surface of the step bar is equal to d2-d1, the step surface of the step bar is attached to the step surface of the stepped hole, and two ends of the step bar are erected on the horse frame; placing a hole-expanding upper anvil at the top of the outer wall of the blank, wherein a first pressing surface, a groove, a second pressing surface and a third pressing surface are sequentially arranged at the bottom of the hole-expanding upper anvil, the first pressing surface and the second pressing surface are attached to the outer wall of the blank on two sides of a connecting pipe, the connecting pipe is positioned in the groove, and the outer end of the connecting pipe is spaced from the bottom of the groove; the third pressing surface is attached to the outer wall of the stepped section of the cylinder body; and pressing the upper reaming anvil downwards to realize reaming.

The invention has the beneficial effects that: the invention firstly carries out pre-treatment on a steel ingot and then carries out upsetting to form a round cake-shaped blank with larger diameter, then the blank is gradually drawn out, an inner stepped hole and an outer annular shoulder are gradually formed in the drawing-out process, and the outer diameter of the blank is gradually reduced, so that when a connecting pipe is formed on the annular shoulder, the outer diameters of the annular shoulder and the blanks at two ends of the annular shoulder are as minimum as possible, thus the radial dimension of the whole blank is small, on one hand, the specification of a connecting pipe forming die can be reduced, the manufacturing cost of the die is reduced, on the other hand, the forming control difficulty of the connecting pipe can be reduced, the forming precision of a pipe nozzle is improved, and the forming quality of the connecting pipe is improved.

Drawings

FIG. 1 is a design drawing of a large variable cross-section cylinder of the present invention;

FIG. 2 is a schematic cross-sectional view A-A of FIG. 1;

FIG. 3 is a schematic illustration of a forging blank;

FIG. 4 is a schematic cross-sectional view A-A of FIG. 3;

FIG. 5 is a schematic view of a pie-shaped blank;

FIG. 6 is a schematic drawing of a pancake shaped billet to provide a cylindrical shaped billet;

FIG. 7 is a schematic illustration of the formation of a stepped bore of a cylindrical blank;

FIG. 8 is a schematic view of a cylindrical billet stepped bore after formation;

FIG. 9 is a schematic view after the shoulder of the band has been pulled out of the surface of the cylindrical blank;

FIG. 10 is a schematic view of the nozzle after it has been formed;

FIG. 11 is a schematic view of the outer wall of the stepped bore large bore section after the barrel step section has been pulled out;

fig. 12 is a schematic reaming view.

Reference numerals: 1-flange section; 2, pipe connection; 3-barrel section; 4-annular belt shoulder; and 5, reaming and hammering.

Detailed Description

The invention is further illustrated with reference to the following figures and examples.

The invention discloses a profile forging process for a large variable cross-section cylinder body integrating multiple connecting pipes, which comprises the following steps of

A. Designing a forging blank according to the structural characteristics of the cylinder part, wherein the design principle is a conformal design, and as shown in fig. 3 and 4, the forging blank comprises a flange section 1, a connecting pipe 2 arranged on the outer wall of the flange section 1 and a cylinder section 3 positioned at one end of the flange section 1; the outer diameter of the flange section 1 is D1, and the inner diameter is D1; the outer diameter of the cylinder section 3 is D2, the inner diameter is D2, the length of the flange section 1 is L1, the length of the cylinder section 3 is L2, the outer diameter of the connecting pipe 2 is D0, the height of the connecting pipe is L0, the corresponding central angles of the two adjacent connecting pipes 2 are respectively alpha and beta, the sizes D0, L0, alpha and beta of the connecting pipe 2 are the same as the designed sizes, namely the connecting pipe is directly formed into a finished size through forging, the appearance, the angle and the like are not adjusted through machining, and the manufacturing efficiency is improved. Because the central hole of the connecting pipe 2 is a slender hole, the forging forming difficulty is high, therefore, the connecting pipe 2 is formed into a solid pipeline during forging, and the central hole is machined after the forging is finished.

B. And (3) upsetting the steel ingot after pretreatment to obtain a round cake-shaped blank, wherein the outer diameter of the round cake-shaped blank is D3, and punching a central through hole on the round cake-shaped blank, wherein the diameter of the central through hole is D3. Specifically, the steel ingot pretreatment process comprises the following steps: upsetting the steel ingot with the as-cast structure, drawing out the steel ingot after upsetting, wherein the upsetting and drawing times are at least 1, and the upsetting and drawing times or the forging ratio depend on the quality requirement of the part. After the upsetting and drawing-out is completed, the head and tail are cut off, and the part with better quality is taken out, so that a cylindrical blank is usually obtained. And upsetting the cylindrical blank to obtain a round cake-shaped blank in order to obtain a blank with a large diameter for preparing subsequent forming. In order to avoid the defect of concave center during the subsequent splitting and drawing of the large-section round cake-shaped blank, the upper and lower concave panels are preferably adopted for upsetting, so that the two end surfaces of the round cake-shaped blank are protruded outwards, and the whole round cake-shaped blank is in a round drum shape, as shown in fig. 5. And punching a central through hole on the round cake-shaped blank to facilitate subsequent hollow drawing.

C. And drawing out the disk-shaped blank to obtain a cylindrical blank, wherein the outer diameter of the cylindrical blank is D4, D4 is less than D3, and the diameter of the central through hole is D4, D4 is less than D3. During drawing, a mandrel penetrates through the central through hole, the diameter of the mandrel is smaller than that of the central through hole, and circular drawing is performed by using the upper flat anvil and the lower V-shaped anvil, as shown in fig. 6. The mandrel can be used for auxiliary positioning and plays a role in axial guiding, and the shape precision of the blank during drawing is ensured.

D. The method is characterized in that cylindrical blanks are subjected to circular drawing, a central through hole is formed into a stepped hole, the diameter of a small hole section of the stepped hole is d6, the diameter of a large hole section is d5, and d5-d6 is d2-d1, so that the hole diameter difference of the stepped hole is equal to the hole diameter difference of a forging blank, the hole diameter difference does not need to be adjusted at the later stage, and the forging process is reduced. At this time, the outer diameter of the cylindrical billet was D5, D5 < D4.

In order to accurately control the diameter difference between the small hole section and the large hole section of the stepped hole, a stepped horse bar is placed in the central through hole, as shown in fig. 7, the stepped horse bar has two sections, the diameter of the thicker section is d5, d5-d 4, the diameter of the thinner section is d6, and d5-d 6-d 2-d1, and the axial position of the stepped horse bar satisfies the following conditions: the weight of the blank corresponding to the thicker section of the step-shaped horse bar is matched with that of the barrel section 3, and the weight of the blank corresponding to the thinner section of the step-shaped horse bar is matched with that of the flange section 1. The thick section of step horse thick corresponds the barrel section 3 of forging blank, the thin section of step horse thick corresponds the flange section 1 of forging blank, the boundary between barrel section 3 and flange section 1 is located the ladder face of shoulder hole, and the ladder face of shoulder hole and the ladder face coincidence of step horse thick stick, therefore, the position of strict control step horse thick stick ladder face can be so that the blank weight distribution of ladder face both sides satisfies flange section 1 and barrel section 3's shaping needs, thereby guarantee the forging quality, avoid appearing the defective products.

After the position of the step bar is determined, the upper flat anvil and the lower V-shaped anvil are used for circular drawing, the outer diameter of the cylindrical blank is reduced from D4 to D5, and meanwhile, a section of the thinner step bar corresponding to the central through hole is contracted to be attached to the step bar, as shown in FIG. 8. Because the outer diameter difference d5-d6 of the step-shaped bar is d2-d1, when the step-shaped bar is drawn out, after the inner wall of the cylindrical blank is completely attached to the step-shaped bar, the aperture difference of the formed step hole is also equal to d2-d1, and the accuracy of the aperture difference is ensured.

E. Drawing out a ring belt shoulder 4 on the surface of the cylindrical blank, wherein the outer diameter of the blank on two sides of the ring belt shoulder 4 is D6, D6 is more than D5, and D6²-d6²＝λD1²-d1²Wherein λ is the coefficient of the reaming dressing. After the step D is finished, the step horse bar is not taken out, and the step horse bar is continuously positioned on the stepIn the ladder hole, the upper flat anvil and the lower V-shaped anvil are utilized to pull out the annular shoulder 4 on the surface of the cylindrical blank, as shown in FIG. 9, the axial length of the annular shoulder 4 is greater than the designed outer diameter of the connecting pipe 2, and the height of the annular shoulder 4 is less than the designed height of the connecting pipe 2, so that the connecting pipe 2 can be formed to the designed size in the following process.

The invention firstly carries out pre-treatment on a steel ingot and then carries out upsetting to form a round cake-shaped blank with larger diameter, then the blank is gradually drawn out, an inner stepped hole and an outer annular shoulder are gradually formed in the drawing-out process, and the outer diameter of the blank is gradually reduced, so that when a connecting pipe is formed on the annular shoulder, the annular shoulder and the outer diameters of the blanks at two ends of the annular shoulder are as minimum as possible, thus the radial dimension of the whole blank is small, on one hand, the specification of a connecting pipe forming die can be reduced, the manufacturing cost of the die is reduced, on the other hand, the forming quality of the connecting pipe can be improved, on the third hand, when the outer diameter of the blank is smaller, the deformation resistance of the forming connecting pipe is reduced, a plurality of even all connecting pipes can be formed at one time, the requirement on the load of a press device is reduced, and the forming efficiency is improved.

F. A plurality of connecting pipes 2 are forged and formed on the ring belt shoulder 4, and the connecting pipes 2 are directly forged to the designed size, as shown in figure 10.

The forming process of the connecting pipe 2 comprises the following steps: firstly, the annular belt convex shoulder 4 is divided to obtain a plurality of nozzle blanks, and then the nozzle blanks are subjected to die forging by using a die to form the connecting pipe 2. The nozzle blank can be formed by adopting the prior art, such as CN105033154A, CN110090914A, CN108705023A and the like, CN105033154A, CN110090914A, CN108705023A adopt a nozzle forming anvil, a triangular knife and the like with a cross section similar to a triangle to press the nozzle blank for forming the nozzle on the convex belt, the nozzle forming anvil, the triangular anvil and the triangular knife move along the radial direction of the convex belt and divide the convex belt during pressing, and the whole barrel body needs to be horizontally placed because the pressure of a large-scale pressing device is generally vertical downwards, and the fixing is troublesome because the shape is circular. In addition, the movement directions of the nozzle forming anvil, the triangular anvil and the triangular knife are difficult to accurately control, and may deviate from the radial direction of the convex belt, so that the metal amount of the obtained nozzle blank has larger deviation from the design value, and the size of the subsequently formed nozzle is easily lower than the design value or has more allowance; in addition, the existing cutter can only form one or two nozzle blanks at one time, and the efficiency is low. In order to solve the problems, the invention adopts a cutting die to form a nozzle blank, the cutting die comprises an annular upper pressing plate and an annular lower baffle plate, the diameter of the central hole of the upper pressing plate and the diameter of the central hole of the lower baffle plate are matched with the outer diameter of the blank at two ends of the annular shoulder 4, the lower surface of the upper pressing plate is provided with a plurality of cutting knives, the length direction of the cutting knives is the radial direction of the upper pressing plate, when the nozzle blank is formed, the blank is vertically placed, the lower baffle plate is fixed on the lower surface of the annular shoulder 4, the upper pressing plate is sleeved on the blank above the annular shoulder 4, downward acting force is applied to the upper pressing plate by using a press to push the upper pressing plate to move downwards, and the cutting knives divide the annular shoulder 4 into a plurality of nozzle blanks. By adopting the mode, the blank is vertically placed, so that the fixing is more convenient; the upper pressing plate is in sliding fit with the blank above the annular belt shoulder 4, the blank can play a role in guiding, the moving direction of the dividing cutter is ensured to be vertically downward, and the metal content of the obtained nozzle blank is the same as the design value; and all nozzle blanks can be formed at one time, so that the efficiency is high.

The process of die forging the nozzle blank into the adapter tube 2 by using the die comprises the following steps: the blank is vertically placed, the forging dies are arranged above and below the annular shoulder 4, each forging die is provided with a plurality of forming cavities, the size of each forming cavity is the same as the design size of the connecting pipe 2, and each forming cavity is aligned to one nozzle blank. The forging die is sleeved on the blanks at the two ends of the annular shoulder 4, the press presses the forging die, the pressure direction is the axial direction of the blanks, and the forging die moves axially under the guiding action of the blanks at the two ends of the annular shoulder 4 and extrudes the annular shoulder 4 to obtain the connecting pipe 2. By adopting the forging mode, all the connecting pipes 2 can be formed at one time, and the blank at the two ends of the annular belt shoulder 4 plays a role in guiding to ensure the forming quality.

The cylinder body step is pulled out from the outer wall of the large hole section of the stepped hole, as shown in fig. 11, the outer diameters of the cylinder body step are D7 and D7²-d5²＝γD2²-d2²And gamma is the coefficient of the reaming dressing, and the lambda is generally more than or equal to 1.05, but the gamma is not too large to cause material waste. At the outer wall of the big hole section of the stepped holeThe process of getting out of the barrel step section is as follows: and D, putting a step horse bar into the stepped hole, wherein the diameter of a thicker section of the step horse bar is D5, and the diameter of a thinner section of the step horse bar is D6, and the step horse bar in the step D can be directly adopted. And the step section of the cylinder body is pulled out by using the upper flat anvil and the lower V-shaped anvil.

The stepped section of the cylinder body can be formed firstly, and then the connecting pipe 2 is formed, but in order to facilitate the utilization of the outer wall of the large hole section of the stepped hole as the guide column of the forging die, the connecting pipe 2 is formed by forging firstly, and then the stepped section of the cylinder body is pulled out from the outer wall of the large hole section of the stepped hole.

G. And (3) reaming the blank to ensure that the diameter of the small hole section of the stepped hole is d1 and the diameter of the large hole section is d2, so as to obtain the forging blank.

The broaching can be performed by adopting various existing broaching equipment, preferably, as shown in fig. 12, a step bar is placed at the top of the stepped hole, the outer diameter of the step bar is smaller than the diameter of the stepped hole, the height of the step surface of the step bar is equal to d2-d1, the step surface of the step bar is attached to the step surface of the stepped hole, and two ends of the step bar are erected on a horse frame; the upper reaming anvil 5 is placed at the top of the outer wall of the blank, a first pressing surface, a groove, a second pressing surface and a third pressing surface are sequentially arranged at the bottom of the upper reaming anvil 5, the first pressing surface and the second pressing surface are attached to the outer wall of the blank on two sides of the connecting pipe 2, the depth of the groove is larger than the height of the connecting pipe 2, and the width of the groove is equal to the outer diameter of the connecting pipe 2. The connecting pipe 2 is positioned in the groove, and a distance is reserved between the outer end of the connecting pipe 2 and the groove bottom of the groove; the third pressing surface is attached to the outer wall of the stepped section of the cylinder body; and (3) pressing the upper reaming anvil 5 downwards to realize reaming, and rotating the blank for a certain angle to continue pressing downwards for reaming every time the pressing is finished. The rotation angle and the deformation of the blank are ensured to be uniform in the reaming process, and the angle deviation of the angle of the connecting pipe 2 due to non-uniform deformation in the reaming process is prevented.

Examples

The forging of the integrated barrel is a multi-fire process, and the heating temperature of blanks at each fire time is required to reach 1100-1250 ℃. The method comprises the steps of selecting a steel ingot made of a low alloy steel as a steel ingot material, heating the steel ingot to 1250 ℃, upsetting, drawing out and deforming, forging and compacting an original thick cast-state structure of the steel ingot thoroughly, cutting the head and removing the tail, and taking a middle section blank with good quality to form an integrated barrel. The cylindrical blank after blanking is upset into a cake-shaped blank with two bulged end faces by using a concave panel, and a through hole is punched in the center, as shown in figure 5. And (3) penetrating a mandrel with the same diameter into an inner hole of the blank, and performing round drawing by using an upper flat V-shaped anvil and a lower flat V-shaped anvil to eliminate the bulging degree of the blank after upsetting, so that the shape of the blank is more regular, as shown in figure 6. The equal-diameter mandrel is replaced by a step-shaped cross bar, and the position of the step-shaped cross bar in the inner hole of the blank is determined through calculation, and the step-shaped cross bar is shown in figure 7. And performing round drawing by using the upper flat V-shaped anvil and the lower flat V-shaped anvil again to manufacture an inner step hole of the blank, as shown in figure 8. The outer circle is further drawn out to form an outer circular ring with a shoulder, thereby producing a nozzle-forming intermediate blank, see fig. 9. The finished nozzle is extruded by using a special die for nozzle forming, and the finished nozzle is shown in figure 10. The inner hole of the blank penetrates into a step horse bar, and the step IV of the excircle is pulled out by utilizing an upper flat V-shaped anvil and a lower V-shaped anvil to prepare an intermediate blank before reaming, which is shown in figure 11. And finally, placing the blank penetrating into the step horse bar on the horse frames at the two ends, and reaming by utilizing a reaming upper anvil matched with the surface of the excircle, wherein the turning angle of the blank is controlled to be uniform in the reaming process, the reduction is controlled to be uniform, and finally, the integrated cylinder body which is formed by profiling with full structural characteristics, meets the requirements of all parts in size and has good surface quality is obtained.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.