NEAR-ISOTHERMAL HOT SPIN FORMING METHOD AND HEAT COMPLEMENTING METHOD FOR METAL WORKPIECE

Abstract

A near-isothermal hot spin forming method and a heat complementing method for a metal workpiece are provided. The forming method comprises: transferring and clamping a blank heated to a spin preheating temperature on a workbench, wherein the blank is located in an effective heat complementing zone provided by a heat complementing system; measuring a temperature of the blank to judge whether the temperature of the blank satisfies a pre-spinning temperature to determine whether the blank waits for temperature complement in the heat complementing system; and completing the near-isothermal hot spinning process in the heat complementing system according to the preset spinning program. During the spinning process, the heat complementing system continuously supplements the temperature of the blank and monitors the spinning temperature in real time to ensure that the fluctuation range of the spinning temperature does not exceed 20 C. from the beginning to the end of the spinning deformation.

Claims

1. A near-isothermal hot spin forming method for a metal workpiece, comprising steps of: heating a blank to a spin preheating temperature; transferring and clamping the heated blank on a workbench rotating with a main shaft of a spinning device, wherein a heat complementing system is mounted on a periphery of the workbench, and the blank is located in an effective heat complementing zone provided by the heat complementing system; measuring a blank temperature of the blank after clamping and fixing, and judging whether the blank temperature T.sub.blank meets a pre-spinning temperature T.sub.b spinning of the blank required by a near-isothermal hot spinning process; if T.sub.blankT.sub.b spinning, starting the spinning device to perform spinning; and if T.sub.blank<T.sub.b spinning, heating and temperature complementing the blank by the heat complementing system until T.sub.blankT.sub.b spinning is satisfied, and then starting the spinning device to perform spinning; and applying the near-isothermal hot spinning process in the spinning device to spinning form the blank; wherein during the near isothermal hot spinning process, the blank is actively heated and temperature complemented by the heat complementing system, and a spinning temperature is monitored in a spinning deformation zone of the blank in real time to ensure that a fluctuation range of the spinning temperature does not exceed 20 C. from the beginning of a spinning deformation to the end.

2. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein a time taken to complete the transferring and clamping of the heated blank on the workbench of the spinning device is taken as a transferring time which is required not to exceed 90 s.

3. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein the spinning device comprises a machine body, a heat complementing system and a spinning roller system; a workbench is mounted on a main shaft of the machine body; the spinning roller system comprises a spinning roller assembly; the heat complementing system comprises a furnace body and a temperature control system; the temperature control system comprises a furnace body temperature measurement module, a control module and a heating module; the heating module comprises a plurality of heating elements; a furnace cavity is formed in the furnace body, wherein the heating element is arranged on an inner wall of the furnace cavity for forming an effective temperature complementing zone in the furnace cavity; a spinning roller movement groove is provided on the furnace body, and the spinning roller assembly passes through the spinning roller movement groove for ensuring that the spinning roller assembly can move freely in a radial direction and a axial direction of the blank; the furnace body temperature measurement module is configured for detecting a temperature of the effective temperature complementing zone; and the furnace body temperature measurement module and the heating module are both electrically connected to the control module.

4. The near-isothermal hot spin forming method for the metal workpiece according to claim 3, wherein the spinning roller assembly comprises an inner spinning roller and an outer spinning roller; during a operation of the spinning roller assembly, all structures of the inner spinning roller and part of structures of the outer spinning roller are located in the effective temperature complementing zone of the heat complementing system; the inner spinning roller is located on an inner side of the blank and can abut against an inner wall of the blank of the workpiece; the outer spinning roller is located on an outer side of the blank and can abut against an outer wall of the blank of the workpiece; and the inner spinning roller and the outer spinning roller pass through the spinning roller movement groove and are located in the spinning roller movement groove, ensuring that the inner spinning roller and the outer spinning roller are free to move independently in the radial direction and the axial direction along the blank.

5. The near-isothermal hot spin forming method for the metal workpiece according to claim 3, wherein the furnace body comprises a furnace body I and a furnace body II, the furnace body I and the furnace body II are provided opposite to each other; the furnace body I and the furnace body II can be close to or away from the workbench; the furnace body I and the furnace body II are close to each other to form the furnace cavity, so that the blank is located in the effective temperature complementing zone of the furnace cavity; a first spinning roller movement groove is provided on the furnace body I; a second spinning roller movement groove is provided on the furnace body II; and the first spinning roller movement groove and the second spinning roller movement groove form the spinning roller movement groove.

6. The near-isothermal hot spin forming method for the metal workpiece according to claim 5, wherein the furnace body I and the furnace body II close the furnace body of the heat complementing system by approaching the workbench; the furnace body I and the furnace body II open the furnace body of the heat complementing system by being away from the workbench; a time taken for the furnace body to complete the closing is controlled within 15 s; and a time taken for the furnace body to complete the opening is controlled within 15 s.

7. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein the blank temperature T.sub.blank is measured on the blank after clamping and fixing, and compared with the pre-spinning temperature T.sub.b spinning required by the near-isothermal hot spinning process; if T.sub.blank<T.sub.b spinning, it starts and waits for the heat complementing system to heat and temperature complement the blank; the heat complementing system adjusts a heating power of a heating element to increase a temperature rising rate of the temperature complementing, actively complement and heat the blank within a specified heat complementing time of the near-isothermal hot spinning process, so that the blank temperature reaches the pre-spinning temperature, and then the spinning device is started for spinning the workpiece according to a predetermined spinning program; and if T.sub.blankT.sub.b spinning, the heat complementing system is started to temperature complement the blank; at the same time, it starts the spinning device to start spinning according to the predetermined spinning program; and the heat complementing system maintains the heating power of the heating element, so as to maintain the blank temperature within a spinning temperature range.

8. The near-isothermal hot spin forming method for the metal workpiece according to claim 7, wherein a temperature of the effective temperature complementing zone of the heat complementing system is not higher than the spin preheating temperature; if T.sub.blank<T.sub.b spinning, it starts the heat complementing system to heat and temperature complement the blank; and the heat complementing time of the heat complementing system does not exceed 5 min.

9. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein the spinning device is further provided with a blank temperature measurement module for detecting the blank temperature of the blank located in an effective temperature complementing zone to obtain the blank temperature or the spinning temperature; and the blank temperature measurement module is externally provided on the heat complementing system or a machine body of the spinning device.

10. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein during the near-isothermal spinning process, the blank is heated and temperature complemented by the heat complementing system, so as to ensure that the fluctuation range of the spinning temperature does not exceed 10 C. from the beginning of the spinning deformation to the end.

11. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein the spinning temperature is 900-1150 C. for the blank of high temperature alloy materials.

12. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein the spinning temperature is 700-900 C. for the blank of titanium alloy materials.

13. The near-isothermal hot spin forming method for the metal workpiece according to claim 1, wherein during the spin forming of the blank by the near-isothermal hot spinning process, a rotation speed of the blank is 50-300 r/min; an feed ratio of a spinning roller is 0.1-3 mm/r; a radius of a round corner of the spinning roller is 0.3 t-2.5 t, wherein t is a wall thickness of the blank; and a reduction rate of each pass does not exceed a limit reduction rate of a blank material, the reduction rate of the each pass being 10-40%.

14. A metal workpiece, wherein the metal workpiece is prepared by the near-isothermal hot spin forming method for the metal workpiece according to claim 1.

15. The metal workpiece according to claim 14, wherein the metal workpiece is one of a rectangular workpiece, a flange workpiece, an I-shaped workpiece, an L-shaped workpiece, a long cylindrical workpiece, a cone part, and an irregular part.

16. A heat complementing method for the near-isothermal hot spin forming method according to claim 1, wherein the heat complementing method comprises steps below: after the heated blank is transferred and clamped on the workbench rotating with the main shaft of the spinning device, the blank is located in an effective temperature complementing zone of the heat complementing system, and the heat complementing system is configured for heating and temperature complementing the blank; by setting a target complement temperature and a heating rate of the heat complementing system, the blank temperature T.sub.blank reaches the pre-spinning temperature T.sub.b spinning required by the near-isothermal hot spinning process, and a calculation formula of the pre-spinning temperature T.sub.b spinning is as follows: $T_{b\mathrm{spinning}}=T_{\mathrm{spinning}}-T$ where T.sub.spinning is the spinning temperature measured in the spinning deformation zone during the spinning process of the workpiece; T is a temperature rise caused by the heat generated by the spinning deformation; after the blank temperature T.sub.blank reaches the pre-spinning temperature T.sub.b spinning required by the near-isothermal hot spinning process, the spinning device is started to perform spinning according to a pre-spinning program; and at the same time, the heating complementing system is started to heat and temperature complement the blank so that the spinning temperature is controlled within a range required by the near-isothermal hot spinning process, with the fluctuation range not exceeding 20 C. from the beginning to the end of the spinning deformation.

17. The heat complementing method according to claim 16, wherein a calculation formula of T is as follows: $T=\frac{Q}{mC}$ where Q is a heat generated by plastic deformation; m is a mass of the blank; and C is a specific heat capacity of a blank material.

18. The heat complementing method according to claim 17, wherein a calculation formula of the heat Q generated by the plastic deformation is as follows: $Q=*\stackrel{}{}*\stackrel{}{}$ where is a deformation thermal effect coefficient; is an equivalent stress at a deformation temperature; and {dot over ()} is an equivalent strain rate of the spinning deformation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0067] FIG. 1 is a schematic cross-sectional view of a blank prepared in Example 1.

[0068] FIG. 2 is a schematic cross-sectional view of a workpiece prepared in Example 1.

[0069] FIG. 3 is a schematic view showing a structure of a heat complementing system and a spinning roller system of a spinning device of the present invention.

[0070] FIG. 4 is a schematic cross-sectional view showing opening and closing states of the heat complementing system of the spinning device according to the present invention.

[0071] FIG. 5 is a schematic top view of the heat complementing system and the spinning roller system of the spinning device according to the present invention.

[0072] FIG. 6 is a schematic cross-sectional view of a blank prepared according to Example 2.

[0073] FIG. 7 is a schematic cross-sectional view of a workpiece prepared in Example 2.

REFERENCE NUMERALS

[0074] 1machine body, 2workbench, 31furnace body I, 32furnace body II, 41outer spinning roller, 42inner spinning roller, 5blank, 6workpiece.

DETAILED DESCRIPTION OF THE INVENTION

[0075] In order to more clearly describe the objects, technical solutions and advantages of the present invention in specific embodiments thereof, the solutions in specific embodiments is described below in detail in combination with the accompanying drawings of the invention. The specific examples described below are intended only to provide a clear and complete description of the inventive aspects of the present invention, which are only a part of the specific examples that can be adopted by the invention, not all embodiments, and are not to be construed as limiting the inventive aspects of the present invention in any way. Any solution employing the same inventive concept of the present invention should be included in the scope of the present invention.

[0076] Secondly, the description related to the drawings in the specific examples of the present invention is merely for the convenience of a person skilled in the art to understand the solution of the present invention, and some details are shown in the drawings for the purpose of facilitating the clear presentation of the technical solution. It should not be considered that all the technical features in the drawings must be included in the specific examples, and the detailed features in the drawings may not be considered as additional limitations on the technical solution of the present invention. The components of the various examples described and illustrated in the figures may be combined in various configurations, and variations of such combinations are considered to be part of all examples of the inventive solutions and are intended to be within the scope of the invention.

[0077] In summary, the solutions or descriptions presented in the specific examples and figures of the present invention are not intended to limit the scope of the claims, but merely represent selected examples/cases that help the skilled person understand the relevant innovative solutions. Based on these examples, all other equivalent or parallel examples obtained by a person skilled in the art without inventive effort fall within the scope of the claimed invention.

[0078] It should be noted that in the description of the specific examples of the present invention, the terms upper, lower, left, right, center, inner, outer, etc. designate directions or positional relationships, unless specifically stated otherwise, based on the expressions of the directions or positional relationships shown in the drawings, or the directions or positional relationships in which the product/device/apparatus of the present invention is conventionally used. These terms of orientation or positional relationship are merely used to facilitate the description of solutions of the present invention or to simplify the description of specific examples for the skilled artisan to quickly understand aspects, and do not indicate or imply that a particular device/component/element must have a particular orientation or be constructed and operated in a particular positional relationship, and thus should not be construed as limiting the present invention.

[0079] In addition, in the description of the technical solution of the present invention, unless explicitly stipulated/defined/limited otherwise, where the terms providing, mounting, connecting, connecting, and providing appear, it should be understood in a broad sense. For example, it may be a fixed connection, or a detachable connection, or an integral connection, and may be a connection means commonly used in the art, such as welding, riveting, bolting, screwing and the like. This connection may be a mechanical connection, or may be an electrical connection or a communication connection. They may be connected directly or indirectly via an intermediate medium, and may be in communication internal to two elements.

Embodiment 1

[0080] The material of the blank is a high-temperature alloy GH4169. The initial wall thickness of the blank 5 before spinning is 15 mm, as shown in FIG. 1. The minimum wall thickness of the workpiece 6 after spinning is designed to be 10.5 mm, as shown in FIG. 2. The spinning reduction rate is 30%. According to the production experience of hot spinning of nickel-based high-temperature alloy, the limit single-pass reduction rate of the workpiece is generally 50-60%, and the maximum reduction rate of the workpiece is less than the limit reduction rate. The single-pass spin forming can be used. In the spinning design, it is made to 10.5 mm by one-pass spinning, with the deformation of 30%, and the length of the spinning section increased from 145 mm to 200 mm. The near-isothermal hot spinning is applied in the spinning of the workpiece, and the spinning is performed in the spinning device.

[0081] As shown in FIGS. 3 and 4, the spinning device integrates a heat complementing system and a spinning roller system. A workbench 2 is mounted on a main shaft of a spinning device body 1. The main shaft may drive the workbench 2 to rotate. The heat complementing system comprises a furnace body and a temperature control system. The temperature control system comprises a furnace body temperature measurement module, a control module and a heating module, and the heating module comprises several heating rods. The structure of the furnace body is a semi-closed movable split-type structure. A furnace cavity is formed in the furnace body. A heating rod is arranged on the inner wall of the furnace cavity for forming an effective temperature complementing zone in the furnace cavity. The furnace body comprises a furnace body I 31 and a furnace body II 32, which are semi-cylindrical cavity structures. The furnace body I 31 and the furnace body II 32 are arranged opposite to each other. The furnace body I 31 and the furnace body II 32 may approach or move away from the workbench 2. The furnace cavity I is formed in the furnace body I 31, the furnace cavity II is formed in the furnace body II 32, and the blank 5 is located in the effective temperature complementing zone when the furnace body I 31 and the furnace body II 32 approach the workbench 1. The furnace body I 31 is provided with a first spinning roller movement groove. The furnace body II 32 is provided with a second spinning roller movement groove. The first spinning roller movement groove and the second spinning roller movement groove form a spinning roller movement groove. The spinning roller system comprises an inner spinning roller 42 and an outer spinning roller 41. When the spinning roller assembly is in operation, all the structures of the inner spinning roller 42 and part of the structures of the outer spinning roller 41 are located in an effective temperature complementing zone of the heat complementing system. The inner spinning roller 42 is located at the inner side of the blank 5 and can abut against the inner wall of the blank 5 of the workpiece. The outer spinning roller 41 is located at the outer side of the blank 5, and the outer spinning roller 41 can abut against the outer wall of the blank 5 of the workpiece. The inner spinning roller 42 and the outer spinning roller 41 pass through the spinning roller movement groove and are located in the spinning roller movement groove. The inner spinning roller 42 and the outer spinning roller 41 may freely move in a radial direction and an axial direction along the blank. The blank radial direction refers to a direction perpendicular to the central axis of the blank. The axial direction of the blank refers to the direction parallel to the central axis of the blank workpiece. The diameter and width of the spinning roller movement groove shall be greater than the diameter of the inner spinning roller and outer spinning roller. The spinning roller movement groove is C-shaped, as shown in FIG. 5, so as to prevent the interference of spinning process.

[0082] The spinning device is provided with a control system for controlling the operation of the heat complementing system and the spinning system. The spinning device is further provided with a blank temperature measurement module, which is externally arranged on the heat complementing system, and the blank temperature measurement module is an infrared temperature measurement sensor for detecting the temperature of the blank located in the effective temperature complementing zone, so as to obtain the blank temperature T.sub.blank or the spinning temperature T.sub.spinning.

[0083] In the spinning process, only when the temperature of the blank reaches the pre-spinning temperature required by the process can the spinning be started. The pre-spinning temperature is obtained empirically or obtained by the calculation formula. The calculation formula of the pre-spinning temperature T.sub.b spinning is as follows:

[00006]$T_{b\mathrm{spinning}}=T_{\mathrm{spinning}}-T$ [0084] where T.sub.spinning is the spinning temperature measured in the spinning deformation zone during the spinning process of the workpiece, in the unit of C.; the spinning temperature can be obtained according to the corresponding thermal processing map of workpiece material; for the spinning temperature of specific metal material as range value, it can be obtained by the material manual or thermal simulation test; T is the temperature rise in C. caused by the heat generated by spinning deformation, and the calculation formula of T is as follows:

[00007]$T=\frac{Q}{mC}$ [0085] where Q is the heat generated by plastic deformation, in the unit of J; m is the mass of blank, in the unit of kg; C is the specific heat capacity of the blank material, in the unit of J/(kg.Math. C.); the calculation formula for the heat Q generated by plastic deformation is as follows:

[00008]$Q=*\stackrel{}{}*\stackrel{}{}$ [0086] where is the thermal effect coefficient of deformation, and 0.9 is generally taken in the plastic deformation of metals; is the equivalent stress at the deformation temperature, and it is convenient to calculate the yield strength s of material at the deformation temperature; {dot over ()} is the equivalent strain rate of spinning deformation;

[00009]$\stackrel{}{}=\frac{n}{2}\ln \left(\frac{1}{1-}\right)$ [0087] where n is the rotational speed of the main shaft of the spinning, in the unit of r/min; is the spinning reduction rate; and

[00010]$=\frac{t_0-t_f}{t_0},$ t0 and tf are the thickness of the blank before and after the spinning, respectively, in the unit of mm.

[0088] The near-isothermal hot spin forming process comprises the following steps. [0089] (1) The blank is heated to a spinning preheat temperature of 1000 C. by a heating device. In the heating process, the set heating temperature of the heating device is 1000 C., and the blank is placed in the heating device and is required to be kept warm. The temperature-holding time is calculated according to the wall thickness of the blank by 0.4-0.8 min/mm, so that the temperature of the blank reaches 1000 C. [0090] (2) The target complement temperature after the furnace body of the heat complementing system is closed is consistent with the spinning temperature required by the process. When the blank is to be placed into the workbench, the furnace body I and the furnace body II of the heat complementing system are away from the workbench to a certain distance to open the furnace body, and the time for opening the furnace body is controlled within 15 s.

[0091] The mechanical arm rapidly transfers and clamps the heated blank and fixes same on the working platform of the spinning device, and the furnace body I and the furnace body II of the heat complementing system are close to the working platform after the clamping, so that the furnace bodies are quickly closed, and the time for the furnace bodies to be closed is controlled within 15 s. [0092] (3) The infrared temperature measurement sensor detects the temperature of the blank at this time, and the control system compares the temperature T.sub.blank of the blank with the calculated pre-spinning temperature T.sub.b spinning. If T.sub.blank

[0094] The formed part was inspected, and the wall thickness of the formed workpiece was uniform without crack defects. According to the mechanical property test standard for the workpiece of high-temperature alloy material, the mechanical properties of the workpiece meet the requirements in a plurality of test results. The grain size of the formed workpiece can reach Grades 7-9 after the test, indicating that the forming accuracy of the forming method of the present invention is very high, and the quality of the workpiece can be ensured, so as to meet the requirements of reliability and durability of the workpiece in various engineering applications.

Embodiment 2

[0095] The material of the blank is Ti64 titanium alloy. The initial wall thickness of the blank 5 before spinning is 26 mm, as shown in FIG. 6. After spinning, the wall thickness of the workpiece 6 is designed to be 15 mm, and the workpiece is a workpiece with a flange, as shown in FIG. 7. The spinning reduction rate is 42%, and it is made to 15 mm by two passes of spinning in the spinning design. The spinning of the workpiece is performed by the near-isothermal hot spinning. The spinning of this example is performed in the spinning device of Example 1.

[0096] The pre-spinning temperature of the Ti64 titanium alloy blank is obtained according to experience or is calculated according to the relationship between the spinning deformation temperature and the deformation temperature rise. In this embodiment, referring to the hot working drawing of Ti64 alloy and in combination with the production experience, the spinning temperature T.sub.spinning is 30-50 C. below the phase transition point. In this embodiment, T.sub.spinning is selected to be 900 C. According to this calculation, the pre-spinning temperature T.sub.b spinning of the blank is about 870 C. The near-isothermal hot spin forming method comprises the following steps. [0097] (1) The blank is heated to a spinning pre-heating temperature of 900 C. by the heating device. In the heating process, the set heating temperature of the heating device is 900 C., and the blank is placed in the heating device and is required to be kept warm. The temperature-holding time is calculated according to the wall thickness of the blank by 0.6-0.8 min/mm. [0098] (2) The target complement temperature after the furnace body of the heat complementing system is closed is consistent with the spinning temperature required by the process. When the blank is to be placed into the workbench, the furnace body I and the furnace body II of the heat complementing system are away from the workbench to a certain distance to open the furnace body, and the time for opening the furnace body is controlled within 15 s.

[0099] The mechanical arm rapidly transfers and clamps the heated blank and fixes same on the working platform of the spinning device, and the furnace body I and the furnace body II of the heat complementing system are close to the working platform after the clamping, so that the furnace bodies are quickly closed, and the time for the furnace bodies to be closed is controlled within 15 s. [0100] (3) The infrared temperature measurement sensor detects the temperature of the blank at this time, and the control system compares the temperature T.sub.blank of the blank with the calculated pre-spinning temperature T.sub.b spinning. If T.sub.blank

[0102] The above steps are repeated to complete two spinning passes until the blank reaches the design size of the workpiece. According to the mechanical property test standard for the titanium alloy workpiece, the mechanical properties of the workpiece meet the requirements in a plurality of test results, and the grain size of the formed workpiece can reach Grades 7-9.

[0103] For a person skilled in the art, when understanding the solutions described in the specific embodiments of the present invention, reference can be made to conventional technical manuals in the art. The reference can be made to make an appropriate understanding or adjustment in those places where the above-mentioned terms appear, and the same or similar technical solutions can be achieved without involving any inventive effort.

[0104] While the above-described embodiments illustrate only the basic principles, main features and/or advantages of the present invention, it will be understood by those skilled in the art that the present invention is not limited to the above-described embodiments, and that the above-described embodiments and the summary of the invention are merely illustrative of the principles and embodiments of the invention. Without deviating from the essence of the innovative idea of the invention, the innovative solution of the invention has various changes and improvements, which fall within the scope of protection required by the invention.