阅读说明：本技术 大型外轮廓突变截面环件近净复合轧制成形方法 (Near-net composite rolling forming method for large-sized outer contour abrupt cross-section ring piece ) 是由 华林 邓加东 钱东升 兰箭 王丰 吴荣文 于 2021-08-05 设计创作，主要内容包括：本发明公开了一种大型外轮廓突变截面环件近净复合轧制成形方法,包括以下步骤：根据目标环形锻件的尺寸形状,将其做分割处理,确定出中间产物异形环坯的尺寸；紧接着,确定初始矩形截面环坯尺寸,在加工出初始矩形截面环坯后,将初始矩形截面环坯外侧安装凹模,初始矩形截面环坯内侧安装芯模,通过对矩形截面环坯进行连续局部径向挤压获得中间产物异形环坯；将中间产物异形环坯进行近净复合轧制,在近净复合轧制时,中间产物异形环坯外侧安装有主轧辊、副轧辊和导向辊,中间产物异形环坯内安装有芯辊。本大型外轮廓突变截面环件近净复合轧制成形方法,其尺寸精度高,材料利用率高,极大的减少了后期机加工成本,同时大大提高了产品的力学性能。(The invention discloses a near-net composite rolling forming method for a large-sized outer contour abrupt cross-section ring piece, which comprises the following steps of: according to the size and shape of the target annular forging, carrying out segmentation treatment on the target annular forging to determine the size of an intermediate product special-shaped annular blank; secondly, determining the size of an initial rectangular-section ring blank, after the initial rectangular-section ring blank is processed, installing a female die on the outer side of the initial rectangular-section ring blank, installing a core die on the inner side of the initial rectangular-section ring blank, and performing continuous local radial extrusion on the rectangular-section ring blank to obtain an intermediate product special-shaped ring blank; and (3) carrying out near-net composite rolling on the intermediate product special-shaped ring blank, wherein a main roller, an auxiliary roller and a guide roller are arranged on the outer side of the intermediate product special-shaped ring blank during the near-net composite rolling, and a core roller is arranged in the intermediate product special-shaped ring blank. The near-net composite rolling forming method for the large-sized ring piece with the abrupt change cross section of the outer contour is high in size precision and material utilization rate, greatly reduces the post machining cost, and greatly improves the mechanical property of a product.)

1. A near-net composite rolling forming method for large-sized outer contour abrupt cross-section ring pieces is characterized by comprising the following steps of:

according to the size and the shape of a target annular forging, carrying out segmentation treatment on the target annular forging, respectively designing ring blanks for each segmented component, combining the ring blanks of the components to determine the size of an intermediate product special-shaped ring blank suitable for near-net rolling forming, and determining the size of an initial rectangular section ring blank according to the size of the intermediate product special-shaped ring blank;

after an initial rectangular-section ring blank is processed according to the determined size of the initial rectangular-section ring blank, a female die is installed on the outer side of the initial rectangular-section ring blank, a core die is installed on the inner side of the initial rectangular-section ring blank, an intermediate product special-shaped ring blank is obtained by performing continuous local radial extrusion on the rectangular-section ring blank, the outer surface of the intermediate product special-shaped ring blank has a sudden change profile, and the size of the working surface of the female die is consistent with the size of the outer surface of the intermediate product special-shaped ring blank;

and performing near-net composite rolling on the intermediate product special-shaped ring blank, wherein a main roller, an auxiliary roller and a guide roller are arranged on the outer side of the intermediate product special-shaped ring blank during the near-net composite rolling, a core roller is arranged in the intermediate product special-shaped ring blank, a rolling working surface is formed by the main roller, the core roller and the auxiliary roller, and the guide roller is used for performing roundness control and rolling stability control to obtain the target annular forging.

2. The near-net composite rolling forming method of the large-sized ring piece with the outer contour and the abrupt change cross section as claimed in claim 1, wherein when an intermediate product is formed into an irregular ring blank, the female die reciprocates in the radial direction of the initial ring blank with the rectangular cross section, the core die axially penetrates through the initial ring blank with the rectangular cross section and drives the initial ring blank with the rectangular cross section to rotate, a local abrupt change profile of the ring blank is formed under the extrusion of the female die along with the extrusion, then the female die returns to the original position, and the core die drives the ring blank to rotate by a preset angle and then stops; and then repeating the extrusion process of the previous step in a circulating way until the abrupt contour of the outer surface of the ring blank is completely formed.

3. The near-net composite rolling forming method for the large-sized outer-contour ring with the sudden change of the cross section as claimed in claim 1, wherein the size of the intermediate product special-shaped ring blank is determined by adopting the following method:

when five steps are arranged on the outer surface of the target annular forging, the target annular forging is divided into a component A and a component B from an axial middle plane, ring blank design is respectively carried out on the divided components to obtain the sizes of the ring blank A and the ring blank B corresponding to the component A and the component B, and then the sizes of the intermediate product special-shaped ring blank are obtained by adding the sizes of the ring blank A and the ring blank B corresponding to the component A and the component B;

and according to the volume and the height of the divided target annular forging piece, the volume and the height of the components A and B always keep unchanged, and the following formula is satisfied:

wherein, V_fAnd B_fRespectively the target annular forging volume and height, and B_f＝B_f1+B_f2+B_f3+B_f4+B_f5，V_Afand B_AfVolume and height, V, of the component A_BfAnd B_BfVolume and height of the component B, D_f1、D_f2、D_f3、D_f4、D_f5Respectively the outer diameter, B, of each step of the target annular forging from top to bottom_f1、B_f2、B_f3、B_f4、B_f5Respectively the height of each step from top to bottom of the target annular forging, d_fIs the inner diameter of the target annular forging;

the middle plane of the middle step of the component A is taken as a limiting surface, the metal of the upper part and the lower part of the limiting surface does not flow mutually, and the volume V of the lower end part of the limiting surface of the component A_AdWith its total volume V_AIs defined as:

according to the principle that the rolling ratio and the volume are unchanged and the height of the divided ring blank and the height of the member are unchanged, the relevant size of the ring blank A corresponding to the member A is calculated according to the following formula:

wherein d is_AIs the inner diameter of the ring blank A, B_AHeight of ring blank A, D_AIs the outer diameter of the step at the lower end of the ring blank A, D_ALIs the outer diameter of the step at the upper end of the ring blank A, B_ALThe height of the step at the upper end of the ring blank A, K is the equivalent rolling ratio, B_AfIs the height of the component A, V_AfIs a volume of component A, and

the middle plane of the middle step of the component B is taken as a limiting surface, the metal of the upper part and the lower part of the limiting surface do not flow mutually, and the volume V of the upper end part of the limiting surface of the component B_BuWith its total volume V_BIs defined as:

according to the principle that the volume is unchanged and the height of the divided ring blank and the height of the member are unchanged, the relevant size of the ring blank B corresponding to the member B is calculated according to the following formula:

wherein d is_BIs the inner diameter of ring blank B, B_BHeight of ring blank B, B_BLIs the height of the step at the lower end of the ring blank B, D_BIs the outer diameter of the step at the upper end of the ring blank B, D_BLIs the outer diameter of a step at the lower end of a ring blank B, B_BLIs the height of the step at the lower end of the ring blank B, B_BfIs the height of the member B, V_BfIs the volume of the member B, and

4. the near-net composite rolling forming method for the large-sized outer-profile ring with the sudden change of the cross section as claimed in claim 3, wherein the initial ring blank with the rectangular cross section is determined by adopting the following formula:

wherein D, B and D are respectively the inner diameter, height and outer diameter of the ring blank with the rectangular section.

5. The near-net composite roll forming method for the large-sized outer-contour ring with the abrupt change cross section as claimed in claim 3, wherein in the continuous local radial extrusion, the feeding displacement u of the female die is calculated according to the following formula:

u＝s+Δs；

wherein s is the extrusion feed amount of the female die after contacting the outer surface of the annular blank with the rectangular cross section, and Delta s is the maximum outer diameter D of the special-shaped annular blank of the intermediate product after extrusion_i-maxThe assembly gap between the die and the die;

in the continuous partial radial extrusion, the rotation angle θ of the core mold is calculated as follows:

wherein, B_cIs the width of the core mold, D_i-maxIs the maximum outer diameter of the special-shaped ring blank of the intermediate product after extrusion, and delta is the extrusion overlap angle.

6. The near-net composite rolling forming method of the large-sized outer contour ring with the sudden change section as claimed in claim 1, wherein in the near-net rolling forming process, the method is divided into three stages of a gripping stage, an expanding stage and a cross rolling stage; in the nip phase, the core roller is set at a speed v₁Feeding to meet the ring biting hole type condition; in the expanding stage, the core roller is at a speed v₂Feeding, wherein the inner diameter and the outer diameter of the ring piece are rapidly enlarged, and the two auxiliary rollers cling to the outer wall of the ring piece at a certain angle to move outwards; in the transverse rolling stage, after the auxiliary roller reaches the designed outer diameter position, the auxiliary roller does not move outwards so as to limit the increase of the radial size of the ring piece, and the core roller is at the speed v₃Feeding to continuously enlarge the inner diameter of the ring member, and combining the main roller and the two auxiliary rollersUnder the action, the profile of the abrupt change deep groove on the outer surface of the ring piece is gradually close to net shape.

7. The near-net composite rolling forming method for the large-sized ring piece with the outer contour and the abrupt change cross section as claimed in any one of claims 1 to 6, wherein the composite rolling adopts a closed rolling pass, and end baffles are arranged at two ends of a main roller to limit the maximum height of the ring piece in the near-net forming process of the composite rolling; the inner side of the end face baffle of the main roller is provided with a chamfer, and the geometric dimension of the working surface of the main roller is consistent with that of the outer surface of the target annular forging;

the two ends of the auxiliary roller are respectively provided with an end face baffle to limit the maximum height of the ring piece, the inner side of the end face baffle of the auxiliary roller is provided with a chamfer, and the outline size of the outer surface of the auxiliary roller is consistent with that of the target annular forging.

8. The near-net combined rolling forming method for the large-sized outer-contour ring with the sudden-change cross section as claimed in claim 3, wherein the outer diameter of the step at the thinnest part of the wall thickness of the target annular forging is D_fiTotal feed of core roll

9. The near-net composite rolling forming method for the large-sized outer-profile ring member with the sudden change of the cross section as claimed in claim 8, wherein the feeding speed v of the core roller is determined by the following formula:

v_min≤v≤v_max

wherein D is_q4For the fourth step of the main roller from top to bottomOuter diameter, n₁Main roll speed, D_CIs the outer diameter of the core roll, beta is the contact friction angle, v_minIs the minimum feed speed, v, of the core roller_maxMaximum feed speed of the core roller, D_BThe contact outer diameter of the intermediate product special-shaped ring blank when the rolling is started.

10. The near-net composite roll forming method for the large-sized outer-profile ring with the sudden-change cross section as claimed in claim 7, wherein the core roll feeding speed is fed according to three stages of an initial rolling biting stage, a rolling reaming stage and a cross rolling filling stage:

feeding amount in rolling and biting stage: Δ H₁＝(0.1～0.25)ΔH；

Feeding speed in the rolling biting stage:

feeding amount in a hole expanding stage: Δ H₂＝(0.6～0.8)ΔH；

Feeding speed in a hole expanding stage:

feed amount in the cross rolling filling stage: Δ H₃＝ΔH-ΔH₁-ΔH₂；

Feeding speed in the cross rolling filling stage:

Technical Field

The invention relates to the technical field of rolling methods, in particular to a near-net composite rolling forming method for a large-sized outer contour abrupt cross-section ring piece.

Background

The large-sized outer contour abrupt cross-section ring member is an annular member with the diameter of more than one meter, a straight wall on the inner surface and a plurality of abrupt deep groove step characteristics on the outer surface. The ring piece is widely applied to key components of important equipment in the fields of aerospace, petrochemical industry, steamships and the like, and has higher requirements on the comprehensive performance of products. The ring rolling is an advanced special manufacturing technology with high efficiency, high quality, low material consumption and low energy consumption, and is a technological method for producing high-quality seamless rings through continuous plastic deformation of blanks. However, for the blank required for rolling the ring with the deep groove abrupt structure on the outer surface, the volume distribution of the ring blank needs to be reasonably designed, otherwise, incomplete filling, folding and other adverse phenomena are easy to occur in the rolling process. At present, the complex annular component is mainly formed by rolling a ring piece to form a ring piece with a rectangular section, and then an outer surface deep groove mutation structure is processed by a cutting method. Although the method can manufacture the components, the method also causes a great deal of waste of raw materials and reduces the processing efficiency; moreover, the machining damages the integrity of the original metal streamline of the component and weakens the mechanical property of the ring piece. Therefore, it is urgently needed to develop a forming process method suitable for large-sized ring pieces with abrupt-change outer profiles, so that the ring pieces are formed with low consumption and high efficiency, the distribution integrity of metal flow lines is improved, and the comprehensive mechanical properties of products are improved.

Disclosure of Invention

The invention mainly aims to provide a near-net composite rolling forming method for a large-sized outer contour abrupt cross-section ring piece, which aims to reduce the machining process and provide the mechanical property of a product.

In order to achieve the aim, the invention provides a near-net composite rolling forming method for a large-sized outer-contour abrupt-change cross-section ring piece, which comprises the following steps of:

according to the size and the shape of a target annular forging, carrying out segmentation treatment on the target annular forging, respectively designing ring blanks for each segmented component, combining the ring blanks of the components to determine the size of an intermediate product special-shaped ring blank suitable for near-net rolling forming, and determining the size of an initial rectangular section ring blank according to the size of the intermediate product special-shaped ring blank;

after an initial rectangular-section ring blank is processed according to the determined size of the initial rectangular-section ring blank, a female die is installed on the outer side of the initial rectangular-section ring blank, a core die is installed on the inner side of the initial rectangular-section ring blank, an intermediate product special-shaped ring blank is obtained by performing continuous local radial extrusion on the rectangular-section ring blank, the outer surface of the intermediate product special-shaped ring blank has a sudden change profile, and the size of the working surface of the female die is consistent with the size of the outer surface of the intermediate product special-shaped ring blank;

and performing near-net composite rolling on the intermediate product special-shaped ring blank, wherein a main roller, an auxiliary roller and a guide roller are arranged on the outer side of the intermediate product special-shaped ring blank during the near-net composite rolling, a core roller is arranged in the intermediate product special-shaped ring blank, a rolling working surface is formed by the main roller, the core roller and the auxiliary roller, and the guide roller is used for performing roundness control and rolling stability control to obtain the target annular forging.

Preferably, when the intermediate product special-shaped ring blank is formed, the female die reciprocates in the radial direction of the initial rectangular-section ring blank, the core die axially penetrates through the initial rectangular-section ring blank and drives the initial rectangular-section ring blank to rotate, a local sudden change profile of the ring blank is formed under the extrusion of the female die along with the extrusion, then the female die returns to the original position, and the core die drives the ring blank to rotate by a preset angle and then stops; and then repeating the extrusion process of the previous step in a circulating way until the abrupt contour of the outer surface of the ring blank is completely formed.

Preferably, the size of the intermediate product shaped ring blank is determined in the following manner:

when five steps are arranged on the outer surface of the target annular forging, the target annular forging is divided into a component A and a component B from an axial middle plane, ring blank design is respectively carried out on the divided components to obtain the sizes of the ring blank A and the ring blank B corresponding to the component A and the component B, and then the sizes of the intermediate product special-shaped ring blank are obtained by adding the sizes of the ring blank A and the ring blank B corresponding to the component A and the component B;

and according to the volume and the height of the divided target annular forging piece, the volume and the height of the components A and B always keep unchanged, and the following formula is satisfied:

wherein, V_fAnd B_fRespectively the target annular forging volume and height, and B_f＝B_f1+B_f2+B_f3+B_f4+B_f5，V_Afand B_AfVolume and height, V, of the component A_BfAnd B_BfVolume and height of the component B, D_f1、D_f2、D_f3、D_f4、D_f5Respectively the outer diameter, B, of each step of the target annular forging from top to bottom_f1、B_f2、B_f3、B_f4、B_f5Respectively the height of each step from top to bottom of the target annular forging, d_fIs the inner diameter of the target annular forging;

in the component A, the middle plane of the middle step is taken as a limiting surface, and the metal of the upper part and the lower part of the limiting surface do not flow mutually, so the component AThe member A limiting the volume V of the lower part of the face_AdWith its total volume V_AIs defined as:

according to the principle that the rolling ratio and the volume are unchanged and the height of the divided ring blank and the height of the member are unchanged, the relevant size of the ring blank A corresponding to the member A is calculated according to the following formula:

wherein d is_AIs the inner diameter of the ring blank A, B_AHeight of ring blank A, D_AIs the outer diameter of the step at the lower end of the ring blank A, D_ALIs the outer diameter of the step at the upper end of the ring blank A, B_ALThe height of the step at the upper end of the ring blank A, K is the equivalent rolling ratio, B_AfIs the height of the component A, V_AfIs a volume of component A, and

similarly, the middle plane of the middle step of the component B is also used as a limiting surface, the metal of the upper part and the metal of the lower part of the limiting surface do not flow mutually, and therefore, the volume V of the upper end part of the limiting surface of the component B_BuWith its total volume V_BIs defined as:

according to the principle that the volume is unchanged and the height of the divided ring blank and the height of the member are unchanged, the relevant size of the ring blank B corresponding to the member B is calculated according to the following formula:

wherein d is_BIs the inner diameter of ring blank B, B_BHeight of ring blank B, B_BLIs the height of the step at the lower end of the ring blank B, D_BIs the outer diameter of the step at the upper end of the ring blank B, D_BLIs the outer diameter of a step at the lower end of a ring blank B, B_BLIs the height of the step at the lower end of the ring blank B, B_BfIs the height of the component B, K_BuLimiting the volume V of the upper end portion of the face for the member B_BuWith its total volume V_BRatio of (V)_BfIs the volume of the member B, and

preferably, the initial rectangular-section ring blank is determined using the following formula:

wherein D, B and D are respectively the inner diameter, height and outer diameter of the ring blank with the rectangular section.

Preferably, in the continuous partial radial extrusion, the feed displacement u of the die is calculated as follows:

u＝s+Δs；

wherein s is the extrusion feed amount of the female die after contacting the outer surface of the annular blank with the rectangular cross section, and Delta s is the maximum outer diameter D of the special-shaped annular blank of the intermediate product_i-maxThe assembly gap between the die and the die;

in the continuous partial radial extrusion, the rotation angle θ of the core mold is calculated as follows:

wherein, B_cIs the width of the core mold, D_i-maxFor intermediate product abnormityThe maximum outer diameter of the ring blank, delta, is the extrusion overlap angle.

Preferably, in the near net rolling forming process, the method is divided into three stages, namely a biting stage, an expanding stage and a cross rolling stage; in the nip phase, the core roller is set at a speed v₁Feeding to meet the ring biting hole type condition; in the expanding stage, the core roller is at a speed v₂Feeding, wherein the inner diameter and the outer diameter of the ring piece are rapidly enlarged, and the two auxiliary rollers cling to the outer wall of the ring piece at a certain angle to move outwards; in the transverse rolling stage, after the auxiliary roller reaches the designed outer diameter position, the auxiliary roller does not move outwards so as to limit the increase of the radial size of the ring piece, and the core roller is at the speed v₃And feeding to continuously enlarge the inner diameter of the ring piece, and gradually forming the sudden change deep groove profile of the outer surface of the ring piece close to net shape under the combined action of the main roller and the two auxiliary rollers.

Preferably, the composite rolling adopts a closed rolling pass, and end face baffles are arranged at two ends of the main roller to limit the maximum height of the ring piece in the near-net forming process of the composite rolling; the inner side of the end face baffle of the main roller is provided with a chamfer, and the geometric dimension of the working surface of the main roller is consistent with that of the outer surface of the target annular forging;

the two ends of the auxiliary roller are respectively provided with an end face baffle to limit the maximum height of the ring piece, the inner side of the end face baffle of the auxiliary roller is provided with a chamfer, and the outline size of the outer surface of the auxiliary roller is consistent with that of the target annular forging.

Preferably, the outer diameter of the step at the thinnest wall thickness of the target annular forging is D_fiThe diameter of the intermediate product special-shaped ring blank is d_ATotal feed of core roll

Preferably, the feeding speed v of the core roller is determined by the following formula:

v_min≤v≤v_max

wherein D is_q4The outer diameter of the fourth step of the main roller from top to bottom, n₁Main roll speed, D_CIs the outer diameter of the core roll, beta is the contact friction angle, v_minIs the minimum feed speed, v, of the core roller_maxMaximum feed speed of the core roller, D_BThe contact outer diameter of the intermediate product special-shaped ring blank when the rolling is started.

Preferably, the feeding speed of the core roller is fed according to three stages of an initial rolling biting stage, a rolling reaming stage and a cross rolling filling stage:

feeding amount in rolling and biting stage: Δ H₁＝(0.1～0.25)ΔH；

Feeding speed in the rolling biting stage:

feeding amount in a hole expanding stage: Δ H₂＝(0.6～0.8)ΔH；

Feeding speed in a hole expanding stage:

feed amount in the cross rolling filling stage: Δ H₃＝ΔH-ΔH₁-ΔH₂；

Feeding speed in the cross rolling filling stage:

the near-net composite rolling forming method for the large-sized outer contour sudden change cross section ring piece is suitable for the special-shaped ring blank required by the large-sized outer contour sudden change cross section ring piece composite rolling forming through reasonable design, the near-net rolling forming of the ring piece is guaranteed, the preparation of the special-shaped ring blank is realized through a continuous local radial extrusion method, the equipment capacity is smaller, and the ring blank forming effect is good. And then, the composite rolling is adopted to limit the growth of the outer contour of the ring piece and promote the metal to fill the shape of the outer contour along the radial direction, so that the near-net forming of the large-sized outer contour abrupt cross-section ring piece can be realized, the forming size precision is high, the material utilization rate is high, the later machining cost is greatly reduced, a product with complete metal streamline distribution can be obtained, and the mechanical property of the product is greatly improved.

Drawings

FIG. 1 is a schematic size diagram of a target ring-shaped forging in the near-net composite roll forming method of the large-sized outer-contour abrupt-change cross-section ring piece of the invention;

FIG. 2a is a schematic size diagram of a target annular forging component A in the near-net combined rolling forming method of the large-sized outer-contour abrupt-change cross-section ring piece of the invention;

FIG. 2B is a schematic size diagram of a target annular forging component B in the near-net composite roll forming method of the large-sized outer-contour abrupt-change cross-section ring piece of the invention;

FIG. 3a is a schematic size diagram of a ring blank A corresponding to a target ring-shaped forging component A in the near-net composite rolling forming method for the large-sized outer-contour abrupt-change-section ring piece of the invention;

FIG. 3B is a schematic size diagram of a ring blank B corresponding to a target ring-shaped forging component B in the near-net combined rolling forming method for the large-sized outer-contour abrupt-change-section ring piece of the invention;

FIG. 4 is a schematic size diagram of an intermediate product special-shaped ring blank in the near-net composite rolling forming method of the large-sized outer contour abrupt cross-section ring piece of the invention;

FIG. 5 is a schematic flow chart of the near-net composite roll forming method of the large-sized outer contour abrupt cross-section ring piece (continuous local radial extrusion forming on the left side, near-net composite roll forming on the right side);

FIG. 6a is a front view of the near-net combined roll forming method for the large-sized outer-profile ring with a sudden change in cross section at the beginning of continuous local radial extrusion forming according to the present invention;

FIG. 6b is a schematic cross-sectional view taken along line A-A of FIG. 6 a;

FIG. 7a is a front view of the near-net combined roll forming method for the large-sized outer-profile ring with a sudden change in cross section at the end of continuous local radial extrusion forming according to the present invention;

FIG. 7b is a schematic cross-sectional view taken along line A-A of FIG. 7 a;

FIG. 8a is a schematic sectional view of the near-net combined roll forming method of the large-sized outer contour abrupt cross-section ring piece at the initial moment when continuous local radial extrusion forming is performed;

FIG. 8b is a schematic cross-sectional view of the near-net combined roll forming method of the large-sized outer-profile abrupt-change-section ring piece after one-time extrusion in the continuous local radial extrusion forming process;

FIG. 8c is a schematic view of a core mold rotation cross section in the continuous local radial extrusion forming process of the near-net combined roll forming method for the large-sized outer contour ring with a sudden change in cross section of the invention;

FIG. 8d is a schematic sectional view of the near-net combined roll forming method of the large-sized outer-profile abrupt-change cross-section ring piece at the end time of continuous local radial extrusion forming according to the present invention;

FIG. 9a is a schematic structural diagram of a main roller in the near-net clad-rolling forming method of the large-sized outer-contour abrupt-change cross-section ring piece according to the present invention;

FIG. 9b is a schematic structural diagram of a secondary roller in the near-net clad-rolling forming method of the large-sized outer-contour abrupt-change-section ring piece according to the present invention;

FIG. 10a is a schematic structural diagram of the near-net clad-rolling forming method of the large-sized outer-profile abrupt-change cross-section ring piece at the initial rolling stage during near-net clad-rolling according to the present invention;

FIG. 10b is a schematic structural diagram of the near-net clad-rolling forming method of the large-sized outer-profile abrupt-change cross-section ring piece at the rolling end stage during near-net clad-rolling according to the present invention;

FIG. 11 is a schematic diagram of a core roller feeding curve during near-net clad-rolling in the near-net clad-rolling forming method of the large-sized outer-profile ring with a sudden change in cross section.

In the figure, 1-concave die, 2-ring blank, 3-core die, 4-main roller, 5-guide roller, 6-core roller, 7-ring piece and 8-auxiliary roller.

The implementation, functional features and advantages of the objects of the present invention will be further explained with reference to the accompanying drawings.

Detailed Description

It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1 to 10b, a near-net composite rolling forming method for a large-sized outer-profile abrupt-change cross-section ring piece comprises the following steps:

step S10, according to the size and shape of the target annular forging, carrying out segmentation treatment on the target annular forging, respectively designing ring blanks for each segmented component, combining the ring blanks of the components to determine the size of an intermediate product special-shaped ring blank suitable for near-net rolling forming, and determining the size of an initial rectangular section ring blank according to the size of the intermediate product special-shaped ring blank;

step S20, after processing an initial rectangular-section ring blank according to the determined size of the initial rectangular-section ring blank, installing a female die 1 on the outer side of the initial rectangular-section ring blank, installing a core die 3 on the inner side of the initial rectangular-section ring blank, and obtaining an intermediate product special-shaped ring blank by performing continuous local radial extrusion on the rectangular-section ring blank, wherein the outer surface of the intermediate product special-shaped ring blank has a sudden change profile, and the size of the working surface of the female die 1 is consistent with the size of the outer surface of the intermediate product special-shaped ring blank;

and step S30, performing near-net composite rolling on the intermediate product special-shaped ring blank, wherein during the near-net composite rolling, a main roller 4, an auxiliary roller 8 and a guide roller 5 are installed on the outer side of the intermediate product special-shaped ring blank, a core roller 6 is installed in the intermediate product special-shaped ring blank, a rolling working surface is formed by the main roller 4, the core roller 6 and the auxiliary roller 8, and roundness control and rolling stability control are performed by the guide roller 5 to obtain the target annular forging.

In step S20, when the intermediate product is formed into a special-shaped ring blank, the female die 1 (provided with an upper female die and a lower female die 1) reciprocates in the radial direction of the initial rectangular-section ring blank, the core die 3 axially penetrates through the initial rectangular-section ring blank and drives the initial rectangular-section ring blank to rotate, a local sudden change profile of the ring blank is formed under the extrusion of the female die 1 along with the extrusion, then the female die 1 returns to the original position, and the core die 3 drives the ring blank to rotate by a preset angle and then stops; and then repeating the extrusion process of the previous step in a circulating way until all the mutation profiles on the outer surface of the ring blank are formed, thereby obtaining the intermediate product of the special-shaped ring blank.

In step S10, referring to fig. 1 to 4, the size of the intermediate product special-shaped ring blank is determined in the following manner:

when five steps are arranged on the outer surface of the target annular forging, the target annular forging is divided into a component A and a component B from an axial middle plane, ring blank design is respectively carried out on the divided components to obtain the sizes of the ring blank A and the ring blank B corresponding to the component A and the component B, and then the sizes of the intermediate product special-shaped ring blank are obtained by adding the sizes of the ring blank A and the ring blank B corresponding to the component A and the component B;

and according to the volume and the height of the divided target annular forging piece, the volume and the height of the components A and B always keep unchanged, and the following formula is satisfied:

wherein, V_fAnd B_fIs the volume and height of the annular forging, and B_f＝B_f1+B_f2+B_f3+B_f4+B_f5，V_Afand B_AfIs the volume and height, V, of the component A_BfAnd B_BfIs the volume and height of the component B, D_f1、D_f2、D_f3、D_f4、D_f5Respectively the outer diameter, B, of each step of the target annular forging from top to bottom_f1、B_f2、B_f3、B_f4、B_f5Respectively the height of each step from top to bottom of the target annular forging, d_fIs the inner diameter of the target annular forging;

the middle plane of the middle step of the component A is taken as a limiting surface, the metal of the upper part and the lower part of the limiting surface does not flow mutually, and therefore, the volume V of the lower end part of the limiting surface of the component A_AdWith its total volume V_AIs defined as:

according to the principle that the rolling ratio and the volume are unchanged, and the height of the ring blank after being divided is unchanged with the height of the member, the relevant size of the ring blank A of the member A is calculated according to the following formula:

wherein d is_AIs the inner diameter of the ring blank A, B_AHeight of ring blank A, D_AIs the outer diameter of the step at the lower end of the ring blank A, D_ALIs the outer diameter of the step at the upper end of the ring blank A, B_ALThe height of the step at the upper end of the ring blank A, K is the equivalent rolling ratio, B_AfIs the height of the component A, K_AuLimiting the volume V of the lower end part of the surface for the component A_AdWith its total volume V_ARatio of (V)_AfIs a volume of component A, and

similarly, the middle plane of the middle step of the component B is also used as a limiting surface, the metal of the upper part and the metal of the lower part of the limiting surface do not flow mutually, and therefore, the volume V of the upper end part of the limiting surface of the component B_BuWith its total volume V_BIs defined as:

according to the principle that the volume is constant and the height of the ring blank is constant with the height of the member after being divided, the relative size of the ring blank B of the member B is calculated according to the following formula, assuming that no axial flow of the metal of the member B from the middle step of the member B can occur:

wherein d is_BIs the inner diameter of ring blank B, B_BHeight of ring blank B, B_BLIs the height of the step at the lower end of the ring blank B, D_BIs the outer diameter of the step at the upper end of the ring blank B, D_BLIs the outer diameter of a step at the lower end of a ring blank B, B_BLIs the height of the step at the lower end of the ring blank B, B_BfIs the height of the component B, K_BuLimiting the volume V of the upper end portion of the face for the member B_BuWith its total volume V_BRatio of (V)_BfIs the volume of the member B, and

the initial ring blank with a rectangular cross section is determined by the following formula:

wherein D, B and D are respectively the inner diameter, height and outer diameter of the ring blank with the rectangular section.

In continuous partial radial extrusion, the feed displacement u of the die 1 is calculated as follows:

u＝s+Δs；

wherein s is the extrusion feed amount of the female die 1 after contacting the outer surface of the annular blank with the rectangular cross section, and Delta s is the maximum outer diameter D of the special-shaped annular blank of the intermediate product_i-maxThe assembling clearance between the die and the die is generally 5-20 mm;

in the continuous partial radial extrusion, the rotation angle θ of the core mold 3 is calculated as follows:

wherein, B_cIs the width of the core mold 3, D_i-maxThe maximum outer diameter of the intermediate product special-shaped ring blank is delta, the extrusion overlap angle is delta, and the value is generally 1-4 degrees.

In the near net rolling forming process, the method is divided into three stages, namely a gripping stage, an expanding stage and a cross rolling stage; in the nip phase, the core roller 6 is at a speed v₁Feeding (low-speed feeding) to meet the ring biting hole type condition; in the expanding phase, the core roller 6 is at a speed v₂Feeding (high speed feeding v)₂Greater than v₁) The inner diameter and the outer diameter of the ring piece are rapidly enlarged, and the two auxiliary rollers 8 cling to the outer wall of the ring piece at a certain angle to move outwards; in the transverse rolling stage, after the secondary roller 8 reaches the designed outer diameter position, the secondary roller does not move outwards so as to limit the increase of the radial size of the ring, and the core roller 6 is at the speed v₃And feeding to continuously enlarge the inner diameter of the ring piece, and gradually forming the sudden change deep groove profile of the outer surface of the ring piece close to net shape under the combined action of the main roller 4 and the two auxiliary rollers 8.

The composite rolling adopts a closed rolling pass, and end face baffles are arranged at two ends of a main roller 4 to limit the maximum height of the ring piece in the near-net forming process of the composite rolling; the inner side of the end face baffle of the main roller 4 is provided with a chamfer (generally taking 2-4 degrees), and the geometric dimension of the working surface of the main roller 4 is consistent with that of the outer surface of the target annular forging;

end face baffles are arranged at two ends of the auxiliary roller 8 to limit the maximum height of the ring piece, chamfers are arranged on the inner sides of the end face baffles of the auxiliary roller 8, and the outline size of the outer surface of the auxiliary roller 8 is consistent with that of a target annular forging.

The outer diameter of the step at the thinnest part of the wall thickness of the target annular forging is D_fiThe diameter of the intermediate product special-shaped ring blank is d_ATotal feed of the core roll 6

In step S30, the feed speed v of the core roller 6 is determined by the following equation:

v_min≤v≤v_max

wherein D is_q4The outer diameter of the fourth step from top to bottom of the main roller, n₁At a main roll 4 rotation speed, D_CThe outer diameter of the core roll 6, beta is the contact friction angle, v_minIs the minimum feed speed, v, of the core roll 6_maxMaximum feed speed of the core roller 6, D_BThe contact outer diameter of the intermediate product special-shaped ring blank when the rolling is started.

Referring to fig. 11, the core roll 6 is fed at a speed in three stages of an initial rolling bite stage, a rolling broaching stage, and a cross rolling filling stage:

feeding amount in rolling and biting stage: Δ H₁＝(0.1～0.25)ΔH；

Feeding speed in the rolling biting stage:

feeding amount in a hole expanding stage: Δ H₂＝(0.6～0.8)ΔH；

Feeding speed in a hole expanding stage:

feed amount in the cross rolling filling stage: Δ H₃＝ΔH-ΔH₁-ΔH₂；

Feeding speed in the cross rolling filling stage:

the roll forming method is described below with a large ring with a sudden change in outer profile. The size of the target annular forging is as follows: d_f＝3720mm,D_f1＝4640mm，B_f1＝200mm,D_f2＝4240mm,B_f2＝240mm， D_f3＝4600mm,B_f3＝180mm，D_f4＝4240mm，B_f4＝220mm，D_f5＝4740mm,B_f5The method comprises the following steps of rolling the alloy material to form a near-net shape with the thickness of 200 mm:

(1) shape and size design of intermediate product special-shaped ring blank

As shown in fig. 1, the target annular forging is divided into two components, component a and component B, from an axial mid-plane section L-L, as shown in fig. 2, wherein the dimensions of component a are: d_f＝3720mm, D_f1＝4640mm，B_f1＝200mm,D_f2＝4240mm,B_f2＝240mm，D_f3＝4600mm,The dimensions of member B are: d_f＝3720mm，D_f3＝4600mm,D_f4＝4240mm，B_f4＝220mm， D_f5＝4740mm,B_f5The ring blank design is carried out on the divided components respectively for 200mm, the sizes of the ring blanks of the components A and B are obtained, and then the sizes of the special-shaped ring blanks of the intermediate products are obtained according to the sizes of the ring blanks of the components A and B, as shown in figure 4.

And sequentially calculating the size of the ring blank of the component according to the fact that the volume and the height of the ring piece are kept unchanged all the time after the ring piece is cut. The dimensions of the ring blank a of the component a are: d_A＝2600mm,D_A＝3500mm，B_A＝530mm，D_AL＝3690mm， B_AL200 mm. The dimensions of the ring blank B of the component B are: d_B＝2600mm,D_B＝3510mm,B_B＝510mm， D_BL＝3820mm，B_BL200mm as shown in figure 3.

According to the sizes of the ring blanks of the components A and B, obtaining an intermediate product special-shaped ring blank ruler as follows: d_A＝2600mm， D_A＝3500mm，B_A＝530mm，D_AL＝3690mm，B_AL＝200mm，d_B＝2600mm，D_B＝3510mm， B_B＝510mm，D_BL＝3820mm，B_BL200mm as shown in figure 4.

(2) Continuous local radial extrusion forming of ring blank with rectangular section

And continuously and locally extruding the annular blank with the rectangular section in the radial direction by a continuous and locally radial extruding forming method to obtain the special-shaped annular blank with the abrupt change profile on the outer surface. In the continuous local radial extrusion forming, the concave die 1 reciprocates in the radial direction of the ring blank, and the core die 3 axially penetrates through the ring blank and drives the ring blank to rotate. With the extrusion, under the extrusion of the female die 1, the local sudden change profile of the ring blank at the forming part; then, the female die 1 returns to the original position, and the core die 3 drives the ring blank to rotate by a preset angle and then stops. And then repeating the extrusion process of the previous step in the cycle until the abrupt contour of the outer surface of the ring blank is completely formed, as shown in figures 6, 7 and 8, and obtaining the intermediate product of the special-shaped ring blank.

In the continuous local radial extrusion, the inner diameter, the height and the outer diameter of the extruded rectangular section ring blank are respectively as follows: d is 2600mm, B is 1040mm, and D is 3610 mm.

In continuous local radial extrusion, the feed displacement u of the die 1 is: 125 mm. Wherein, the maximum outer diameter D of the die 1 and the ring blank abrupt change profile₅The gap Δ s therebetween was taken to be 15 mm.

In the continuous partial radial extrusion, the rotation angle θ of the core mold 3 is: -48 °. Wherein the extrusion overlap angle δ takes 3 °.

(3) Composite rolling forming of large-sized outer contour abrupt cross section ring piece

In the near-net composite rolling forming process, a rolling working surface is formed by the main roller 4, the core roller 6 and the auxiliary roller 8, and roundness control and rolling stability control are performed by the guide roller 5. The whole near-net rolling forming process is divided into three stages, namely a gripping stage, an expanding stage and a cross rolling stage. In the bite stage, the core roll 6 is fed at a low speed to satisfy the ring bite pass condition. In the expanding stage, the core roller 6 is fed at a high speed, the inner diameter and the outer diameter of the ring are rapidly expanded, and the two auxiliary rollers 8 cling to the outer wall of the ring at a certain angle to move outwards. In the transverse rolling stage, after the auxiliary roller 8 reaches the designed outer diameter position, the auxiliary roller does not move outwards, so that the increase of the radial size of the ring piece is limited; at the moment, the feeding speed of the core roller 6 is reasonably regulated, the inner diameter of the ring piece is continuously enlarged, and under the combined action of the main roller 4 and the two auxiliary rollers 8, the profile of the sudden change deep groove on the outer surface of the ring piece is gradually close to net forming, as shown in figure 10.

In the scheme, the closed rolling pass is adopted in the composite rolling, and the main roller 4 is provided with the end face baffle plate so as to ensure that the axial height of the ring piece is basically kept unchanged in the near-net forming process of the composite rolling. In consideration of demoulding, the inner sides of the two end surfaces of the main roller 4 are provided with chamfers, and the chamfers are 3 degrees. In addition, the geometry of the working surface of the main roll 4 is consistent with the geometry of the outer surface of the ring forging, ensuring that the component is rolled accurately to near net shape, as shown in fig. 9 a.

In the scheme, the auxiliary roller 8 for the composite rolling near-net forming is also provided with an end face baffle plate and is also used for limiting the axial metal movement of the ring piece in the rolling process. The end face baffle is also provided with a chamfer angle, and the chamfer angle is 3 degrees. The height of the working surface of the secondary roller 8 is basically consistent with the height of the forging, and the outline dimension of the outer surface is basically consistent with the outline dimension of the forging, as shown in fig. 9 b.

In the scheme, the outer diameter of the step at the thinnest part of the wall thickness of the target annular forging piece is D_f2＝D_f44240mm, the diameter of the inner hole of the ring blank formed by extruding the large-sized outer contour sudden change cross section ring piece is d_AWhen 2600mm, the total feed amount Δ H of the core roller 6 becomes 195 mm.

The feeding speed of the core roller 6 is planned according to three stages of an initial rolling biting stage, a rolling reaming stage and a cross rolling filling stage, as shown in fig. 11:

the feeding amount in the rolling and biting stage is 30mm, and the initial rolling feeding speed is 1 mm/s;

the feeding amount in the reaming stage is 156mm, and the feeding speed in the main rolling stage is 2 mm/s;

the feeding amount in the transverse rolling filling stage is 9mm, and the feeding speed in the transverse rolling stage is 1.2 mm/s;

the near-net composite rolling forming method for the large-sized outer contour abrupt cross-section ring piece is suitable for the special-shaped ring blank required by the large-sized outer contour abrupt cross-section ring piece composite rolling forming through reasonable design, the near-net rolling forming of the ring piece is guaranteed, the preparation of the special-shaped ring blank is realized through a continuous local radial extrusion method, the equipment capacity is smaller, and the ring blank forming effect is good. And then, the composite rolling is adopted to limit the growth of the outer contour of the ring piece and promote the metal to fill the shape of the outer contour along the radial direction, so that the near-net forming of the large-sized outer contour abrupt cross-section ring piece can be realized, the forming size precision is high, the material utilization rate is high, the later machining cost is greatly reduced, a product with complete metal streamline distribution can be obtained, and the mechanical property of the product is greatly improved.

The above description is only for the preferred embodiment of the present invention and is not intended to limit the scope of the present invention, and all equivalent structural changes made by using the contents of the present specification and the drawings, or any other related technical fields, are intended to be covered by the scope of the present invention.