阅读说明：本技术 一种薄壁镁合金环件的成形方法 (Forming method of thin-wall magnesium alloy ring piece ) 是由 夏祥生 肖寒 吴洋 万元元 彭菲菲 陈强 项运良 于 2021-08-27 设计创作，主要内容包括：本发明提供了一种薄壁镁合金环件的成形方法：将加热后的环扎坯圈转移至环轧机上就位,将低电压加热装置的正极导电部与负极导电部接入环扎坯圈,使正极导电部、负极导电部分别与环扎坯圈平稳接触；通电后,正极导电部、环扎坯圈、负极导电部和低电压加热装置共同形成加热回路；开启低电压加热装置,使环扎坯圈通过自身的电阻进行加热；当环扎坯圈的温度达到预设温度后,关闭低电压加热装置,并开始环形轧制；环扎过程中实时监测环件表面温度,一旦表面温度低于设定温度下限时立即开启加热装置,一旦环件表面温度高于预设温度上限时立即关闭低电压加热装置。本发明制备的环件表面质量优良,整个表面无开裂、表层拉裂等变形缺陷,力学性能好。(The invention provides a forming method of a thin-wall magnesium alloy ring piece, which comprises the following steps: transferring the heated ring rolling blank ring to a ring rolling machine to be in place, and connecting a positive electrode conductive part and a negative electrode conductive part of a low-voltage heating device into the ring rolling blank ring to enable the positive electrode conductive part and the negative electrode conductive part to be in stable contact with the ring rolling blank ring respectively; after the power is switched on, the positive electrode conducting part, the ring binder blank ring, the negative electrode conducting part and the low-voltage heating device form a heating loop together; starting a low-voltage heating device to heat the cerclage blank ring through the resistance of the cerclage blank ring; when the temperature of the ring rolling blank ring reaches the preset temperature, closing the low-voltage heating device and starting ring rolling; and monitoring the surface temperature of the ring piece in real time in the cerclage process, immediately starting the heating device once the surface temperature is lower than a set temperature lower limit, and immediately closing the low-voltage heating device once the surface temperature of the ring piece is higher than a preset temperature upper limit. The ring piece prepared by the method has the advantages of excellent surface quality, no deformation defects such as cracking and surface layer tension cracking on the whole surface, and good mechanical property.)

1. A forming method of a thin-wall magnesium alloy ring piece is characterized by comprising the following steps:

transferring the heated ring rolling blank ring to a ring rolling machine to be in place, and connecting a positive electrode conductive part (5) and a negative electrode conductive part (4) of a low-voltage heating device into the ring rolling blank ring to enable the positive electrode conductive part (5) and the negative electrode conductive part (4) to be in stable contact with the ring rolling blank ring respectively; after the power is switched on, the positive electrode conducting part (5), the ring binder blank ring, the negative electrode conducting part (4) and the low-voltage heating device form a heating loop together;

starting a low-voltage heating device to heat the cerclage blank ring through the resistance of the cerclage blank ring;

when the temperature of the ring rolling blank ring reaches the preset temperature, closing the low-voltage heating device and starting ring rolling; and in the cerclage process, the surface temperature of the ring piece (6) is monitored in real time, the heating device is immediately started once the surface temperature is lower than the set temperature lower limit, and the low-voltage heating device is immediately closed once the surface temperature of the ring piece (6) is higher than the preset temperature upper limit.

2. The method for forming the thin-wall magnesium alloy ring piece according to claim 1, wherein the method comprises the following steps: in the cerclage process, the positive electrode conducting part (5) and the negative electrode conducting part (4) are expanded along with the expansion of the diameter of the ring piece (6) and are reduced along with the reduction of the thickness of the ring piece (6).

3. The method for forming the thin-walled magnesium alloy ring according to claim 1 or 2, wherein: the positive electrode conductive part (5) and the negative electrode conductive part (4) are conductive wheels or conductive rollers.

4. The method for forming the thin-wall magnesium alloy ring piece according to claim 3, wherein the method comprises the following steps: the positive electrode conducting part (5) is attached to the inner side wall of the ring piece (6), and the negative electrode conducting part (4) is attached to the outer side wall of the ring piece (6).

5. The method for forming the thin-wall magnesium alloy ring piece according to claim 3, wherein the method comprises the following steps: the positive electrode conducting part (5) is attached to the upper surface of the ring piece (6), and the negative electrode conducting part (4) is attached to the lower surface of the ring piece (6).

6. The method for forming the thin-wall magnesium alloy ring piece according to claim 5, wherein the method comprises the following steps: an insulating spring is arranged between the positive electrode conductive part (5) and the negative electrode conductive part (4), the upper end of the insulating spring is fixedly connected with the positive electrode conductive part (5) through an insulating spring connecting piece, the lower end of the insulating spring is fixedly connected with the negative electrode conductive part (4) through an insulating spring connecting piece, the thickness of the ring rolling blank ring is equal to the length of the insulating spring in a free state, the thickness of a finished ring (6) is equal to the length of the insulating spring pressed to a limit position by the positive electrode conductive part (5), and the limit position is the maximum position of the insulating spring pressed by the gravity of the positive electrode conductive part (5).

7. The method for forming the thin-walled magnesium alloy ring according to claim 6, wherein: and the two sides of the cerclage blank ring are provided with insulating springs which comprise a first insulating spring (3) and a second insulating spring (7).

8. The method for forming the thin-wall magnesium alloy ring piece according to claim 7, wherein the method comprises the following steps: when the upper surface of the thin-wall magnesium alloy ring piece is an inclined plane, a balancing weight is arranged on the insulating spring close to the low point side of the inclined plane, so that the positive electrode conducting part (5) is always attached to the surface of the ring piece (6).

9. The method for forming the thin-walled magnesium alloy ring according to claim 8, wherein: the finished product of the thin-wall magnesium alloy ring piece has the inner diameter of 500-600mm, the outer diameter of 700-900mm and the thickness of 19-30 mm.

Technical Field

The invention relates to the technical field of manufacturing of magnesium alloy rings, in particular to a forming method of a thin-wall magnesium alloy ring.

Background

Prior document CN105728604A discloses a forging forming method of a large-outer-diameter magnesium alloy annular forging, which mainly comprises the following steps: cutting a magnesium alloy extrusion rod with a corresponding length or an ingot casting multiple-length material section with a dead head removed, heating the material section, upsetting and forging, manufacturing a ring blank, punching a center, preheating, taking out the material section from a furnace, putting the material section on a ring rolling machine for ring rolling, and discontinuously lubricating working surfaces of a rolling roller, a rolling wheel and a holding roller during the ring rolling process to finish forging and forming of the magnesium alloy annular forging.

However, thin-walled (wall thickness not greater than 35mm) magnesium alloy ring pieces prepared by the method or by the conventional multi-pass ring rolling process have the problems of large-area cracks on the surface of the ring piece, poor mechanical properties of the ring piece and even deformation failure.

Disclosure of Invention

The invention aims to provide a forming method of a thin-wall magnesium alloy ring piece, which is used for solving the technical problems of large-area cracking on the surface of the thin-wall magnesium alloy ring piece prepared by the existing process and poor mechanical property of the ring piece.

In order to achieve the above object, the present invention adopts the following technical solutions.

A forming method of a thin-wall magnesium alloy ring piece is characterized by comprising the following steps:

transferring the heated ring rolling blank ring to a ring rolling machine to be in place, and connecting a positive electrode conductive part and a negative electrode conductive part of a low-voltage heating device into the ring rolling blank ring to enable the positive electrode conductive part and the negative electrode conductive part to be in stable contact with the ring rolling blank ring respectively; after the power is switched on, the positive electrode conducting part, the ring binder blank ring, the negative electrode conducting part and the low-voltage heating device form a heating loop together;

starting a low-voltage heating device to heat the cerclage blank ring through the resistance of the cerclage blank ring;

when the temperature of the ring rolling blank ring reaches the preset temperature, closing the low-voltage heating device and starting ring rolling; and in the cerclage process, monitoring the surface temperature of the ring piece in real time, immediately starting the heating device once the surface temperature is lower than a set temperature lower limit, and immediately closing the low-voltage heating device once the surface temperature of the ring piece is higher than a preset temperature upper limit. In the invention, the blank ring before being subjected to ring rolling is called a ring rolling blank ring, and the blank ring in the ring rolling process is called a ring piece.

Further, in the ring binding process, the positive electrode conducting part and the negative electrode conducting part are expanded along with the expansion of the diameter of the ring piece, and are reduced along with the reduction of the thickness of the ring piece.

In order to improve the flexibility in the ring rolling process, the positive electrode conductive part and the negative electrode conductive part are conductive wheels or conductive rollers.

In a preferred embodiment of the present invention, the positive conductive part abuts against an inner side wall of the ring, and the negative conductive part abuts against an outer side wall of the ring.

In another preferred embodiment of the present invention, the positive electrode conductive part abuts against the upper surface of the ring, and the negative electrode conductive part abuts against the lower surface of the ring.

In order to improve the stability in the ring rolling process, an insulating spring is arranged between the positive electrode conductive part and the negative electrode conductive part, the upper end of the insulating spring is fixedly connected with the positive electrode conductive part through an insulating spring connecting piece, the lower end of the insulating spring is fixedly connected with the negative electrode conductive part through an insulating spring connecting piece, the thickness of a ring rolling blank ring is equal to the length of the insulating spring in a free state, the thickness of a finished ring is equal to the length of the insulating spring when the insulating spring is pressed down to a limit position by the positive electrode conductive part, and the limit position is the maximum position where the insulating spring is pressed down only through the gravity of the positive electrode conductive part.

In order to further improve the stability in the ring rolling process, insulating springs are arranged on two sides of the ring rolling blank ring and comprise a first insulating spring and a second insulating spring.

Further, when the upper surface of the thin-wall magnesium alloy ring piece is an inclined plane, a balancing weight is arranged on the insulating spring close to the low point side of the inclined plane, so that the positive electrode conducting part is always attached to the surface of the ring piece. In this way, the rolling method is particularly suitable for rolling the opposite ring piece with the upper surface being a bevel.

As a preferable scheme of the invention, the finished product of the thin-wall magnesium alloy ring piece has the inner diameter of 500-600mm, the outer diameter of 700-900mm and the thickness of 19-30 mm.

Has the advantages that: the thin-wall magnesium alloy ring prepared by the method has the advantages of good surface quality, no deformation defects such as cracking and surface layer tension cracking on the whole surface, good mechanical property and high production efficiency; the method for preparing the thin-wall magnesium alloy ring piece only needs to be simply improved on the basis of the existing ring rolling equipment, has low implementation cost and simple operation, and is suitable for large-scale industrial production.

Drawings

FIG. 1 is a schematic view of a ring rolling state in the example;

FIG. 2 is a schematic view of a conductive portion in the ring rolling process in example 1;

FIG. 3 is a schematic view of a conductive portion in the ring rolling process in example 2;

FIG. 4 is a schematic view of a conductive portion in the ring rolling process in example 3;

FIG. 5 is a schematic view showing a ring rolling state in example 4.

Detailed Description

The present invention will be further described with reference to the accompanying drawings and specific embodiments, but the following embodiments are only used for understanding the principle of the present invention and the core idea thereof, and do not limit the scope of the present invention. It should be noted that modifications to the invention as described herein, which do not depart from the principles of the invention, are intended to be within the scope of the claims which follow.

Example 1

A forming method of a thin-wall magnesium alloy ring piece is characterized in that the thin-wall magnesium alloy ring piece is made of AZ80 magnesium alloy, the inner diameter of a finished thin-wall magnesium alloy ring piece is 500mm, the outer diameter of the finished thin-wall magnesium alloy ring piece is 700mm, and the thickness (height) of the finished thin-wall magnesium alloy ring piece is 22mm, and the method comprises the following concrete preparation steps:

as shown in fig. 1 and 2, the hot (heated to 350 ℃) cerclage blank ring is transferred to a cerclage mill to be in place, and a positive conductive part 5 and a negative conductive part 4 of a low-voltage heating device are connected into the cerclage blank ring, so that the positive conductive part 5 and the negative conductive part 4 are respectively in stable contact with the cerclage blank ring; after electrifying, the positive electrode conducting part 5, the ring binder blank ring, the negative electrode conducting part 4 and the low-voltage heating device form a heating loop together;

the positive electrode conductive part 5 and the negative electrode conductive part 4 are conductive wheels, the positive electrode conductive part 5 is attached to the upper surface of the ring member 6, and the negative electrode conductive part 4 is attached to the lower surface of the ring member 6; two insulating springs are arranged between the positive electrode conductive part 5 and the negative electrode conductive part 4 and comprise a first insulating spring 3 and a second insulating spring 7, the upper ends of the two insulating springs are fixedly connected with the positive electrode conductive part 5 through an insulating spring connecting piece, the lower ends of the two insulating springs are fixedly connected with the negative electrode conductive part 4 through an insulating spring connecting piece, the thickness of the ring rolling blank ring is equal to the length of the insulating spring in a free state, and the thickness of the finished ring 6 is equal to the length of the insulating spring pressed to the limit position by the positive electrode conductive part 5; the adopted spring connecting piece is provided with a circular ring which can be sleeved and fixed on the conductive wheel so as to be convenient for the fixed connection of the insulating spring and the conductive wheel;

starting a low-voltage heating device to heat the cerclage blank ring through the resistance of the cerclage blank ring;

when the temperature of the ring rolling blank ring reaches the preset temperature, the preset heating temperature is 360 ℃, the low-voltage heating device is closed, and ring rolling is started; in the cerclage process, the positive electrode conducting part 5 and the negative electrode conducting part 4 are expanded along with the expansion of the diameter of the ring 6 and are reduced along with the reduction of the thickness of the ring 6; and in the cerclage process, the surface temperature of the ring 6 is monitored in real time, the heating device is immediately started once the surface temperature is lower than the set temperature lower limit, and the low-voltage heating device is immediately closed once the surface temperature of the ring 6 is higher than the preset temperature upper limit.

Example 2

A forming method of a thin-wall magnesium alloy ring piece is characterized in that the thin-wall magnesium alloy ring piece is made of AZ80 magnesium alloy, the inner diameter of a finished thin-wall magnesium alloy ring piece is 55mm, the outer diameter of the finished thin-wall magnesium alloy ring piece is 800mm, and the thickness (height) of the finished thin-wall magnesium alloy ring piece is 25mm, and the method comprises the following concrete preparation steps:

as shown in fig. 1 and fig. 3, the hot (heated to 330 ℃) cerclage blank ring is transferred to a cerclage mill to be in place, and a positive conductive part 5 and a negative conductive part 4 of a low-voltage heating device are connected into the cerclage blank ring, so that the positive conductive part 5 and the negative conductive part 4 are respectively in stable contact with the cerclage blank ring; after electrifying, the positive electrode conducting part 5, the ring binder blank ring, the negative electrode conducting part 4 and the low-voltage heating device form a heating loop together;

the positive electrode conductive part 5 and the negative electrode conductive part 4 are conductive rollers, the positive electrode conductive part 5 is attached to the upper surface of the ring member 6, and the negative electrode conductive part 4 is attached to the lower surface of the ring member 6;

starting a low-voltage heating device to heat the cerclage blank ring through the resistance of the cerclage blank ring;

when the temperature of the ring rolling blank ring reaches the preset temperature, the preset heating temperature is 365 ℃, the low-voltage heating device is closed, and ring rolling is started; in the cerclage process, the positive electrode conducting part 5 and the negative electrode conducting part 4 are expanded along with the expansion of the diameter of the ring 6 and are reduced along with the reduction of the thickness of the ring 6; and in the cerclage process, the surface temperature of the ring 6 is monitored in real time, the heating device is immediately started once the surface temperature is lower than the set temperature lower limit, and the low-voltage heating device is immediately closed once the surface temperature of the ring 6 is higher than the preset temperature upper limit.

Example 3

A forming method of a thin-wall magnesium alloy ring piece is characterized in that the thin-wall magnesium alloy ring piece is made of AZ80 magnesium alloy, the inner diameter of a finished thin-wall magnesium alloy ring piece is 600mm, the outer diameter of the finished thin-wall magnesium alloy ring piece is 900mm, the thickness (height) of the finished thin-wall magnesium alloy ring piece is 30mm, the upper surface of the thin-wall magnesium alloy ring piece is an inclined plane, and the method comprises the following specific preparation steps:

as shown in fig. 1 and 4, the hot (heated to 340 ℃) cerclage blank ring is transferred to a cerclage mill to be in place, and a positive conductive part 5 and a negative conductive part 4 of a low-voltage heating device are connected into the cerclage blank ring, so that the positive conductive part 5 and the negative conductive part 4 are respectively in stable contact with the cerclage blank ring; after electrifying, the positive electrode conducting part 5, the ring binder blank ring, the negative electrode conducting part 4 and the low-voltage heating device form a heating loop together;

the positive electrode conductive part 5 and the negative electrode conductive part 4 are conductive wheels, the positive electrode conductive part 5 is attached to the upper surface of the ring member 6, and the negative electrode conductive part 4 is attached to the lower surface of the ring member 6; two insulating springs are arranged between the positive electrode conductive part 5 and the negative electrode conductive part 4 and comprise a first insulating spring 3 and a second insulating spring 7, the upper ends of the two insulating springs are fixedly connected with the positive electrode conductive part 5 through an insulating spring connecting piece, the lower ends of the two insulating springs are fixedly connected with the negative electrode conductive part 4 through an insulating spring connecting piece, the thickness of the ring rolling blank ring is equal to the length of the insulating spring in a free state, and the thickness of the finished ring 6 is equal to the length of the insulating spring pressed to the limit position by the positive electrode conductive part 5; a balancing weight is arranged on the insulating spring close to one side of the low point of the inclined plane, and the positive electrode conductive part 5 is attached to the surface of the ring piece 6 all the time;

starting a low-voltage heating device to heat the cerclage blank ring through the resistance of the cerclage blank ring;

when the temperature of the ring rolling blank ring reaches the preset temperature, the preset heating temperature is 360 ℃, the low-voltage heating device is closed, and ring rolling is started; in the cerclage process, the positive electrode conducting part 5 and the negative electrode conducting part 4 are expanded along with the expansion of the diameter of the ring 6 and are reduced along with the reduction of the thickness of the ring 6; and in the cerclage process, the surface temperature of the ring 6 is monitored in real time, the heating device is immediately started once the surface temperature is lower than the set temperature lower limit, and the low-voltage heating device is immediately closed once the surface temperature of the ring 6 is higher than the preset temperature upper limit.

Example 4

A forming method of a thin-wall magnesium alloy ring piece is characterized in that the thin-wall magnesium alloy ring piece is made of AZ80 magnesium alloy, the inner diameter of a finished thin-wall magnesium alloy ring piece is 520mm, the outer diameter of the finished thin-wall magnesium alloy ring piece is 720mm, and the thickness (height) of the finished thin-wall magnesium alloy ring piece is 30mm, and the method comprises the following concrete preparation steps:

as shown in fig. 5, the hot (heated to 340 ℃) cerclage blank ring is transferred to a cerclage mill to be in place, and the positive conductive part 5 and the negative conductive part 4 of the low-voltage heating device are connected into the cerclage blank ring, so that the positive conductive part 5 and the negative conductive part 4 are respectively in stable contact with the cerclage blank ring; after electrifying, the positive electrode conducting part 5, the ring binder blank ring, the negative electrode conducting part 4 and the low-voltage heating device form a heating loop together;

the positive electrode conductive part 5 and the negative electrode conductive part 4 are conductive wheels, the positive electrode conductive part 5 is attached to the inner side wall of the ring member 6, and the negative electrode conductive part 4 is attached to the outer side wall of the ring member 6;

starting a low-voltage heating device to heat the cerclage blank ring through the resistance of the cerclage blank ring;

when the temperature of the ring rolling blank ring reaches the preset temperature, the preset heating temperature is 360 ℃, the low-voltage heating device is closed, and ring rolling is started; in the cerclage process, the positive electrode conducting part 5 and the negative electrode conducting part 4 are expanded along with the expansion of the diameter of the ring 6 and are reduced along with the reduction of the thickness of the ring 6; and in the cerclage process, the surface temperature of the ring 6 is monitored in real time, the heating device is immediately started once the surface temperature is lower than the set temperature lower limit, and the low-voltage heating device is immediately closed once the surface temperature of the ring 6 is higher than the preset temperature upper limit.

In each example: specific parameters of the ring rolling process are calculated, selected and determined by technicians in the field according to the specification of the thin-wall magnesium alloy ring piece; the positive electrode conductive part 5 is connected with the fixed shaft 1, the negative electrode conductive part 4 is connected with the fixed shaft 2, and the fixed shaft 1 and the fixed shaft 2 are both connected with a heating arm (mechanical arm) which can adjust the position and the angle of a working end according to rolling requirements. For example, in embodiment 3, the inclination angle of the working end of the heating arm corresponding to the fixed shaft 2 needs to be consistent with the inclination angle of the inclined surface of the ring 6.

The thin-wall magnesium alloy ring piece prepared in the example is subjected to apparent detection and mechanical property detection, and the result is shown in table 1.

TABLE 1 apparent condition and mechanical properties of thin-walled magnesium alloy ring

The thin-wall magnesium alloy ring piece prepared by the method has the advantages of excellent surface quality, no deformation defects such as cracking and surface layer tension cracking on the whole surface, good mechanical property, room-temperature tensile strength of the prepared thin-wall magnesium alloy ring piece above 349MPa, and elongation after fracture above 8.5%. The thin-wall magnesium alloy ring prepared by the method has high production efficiency, and the production efficiency can be at least improved by several times compared with that of the conventional hot tapping.