A method of forming a thin-walled ring by stacking and rolling

Abstract

This invention discloses a method for forming thin-walled rings by stacking and rolling, relating to the field of material forming technology. The invention includes the following steps: S1: Fitting, designing and manufacturing an inner ring body, an outer ring body, and a composite layer, and assembling the inner ring body, outer ring body, and composite layer together; S2: Heating; S3: Rolling, placing the heated ring on a rolling mill for rolling; S4: Turning the end faces, cleaning the weld joints on the upper and lower end faces of the rolled ring; S5: Pressing out the ring, using a free forging hydraulic press to press the inner ring body out from the outer ring body; S6: Bulging; S7: Machining and delivery. This invention, through fitting, welding, heating, rolling, turning the end faces, pressing out, and bulging, can achieve the rolling and forming of rings with a wall thickness <30mm and a diameter >1000mm. It is particularly suitable for the production of thin-walled rings made of difficult-to-deform alloys such as titanium alloys and high-temperature alloys, solving the problems of low yield and high welding stress in existing ring forming methods for producing thin-walled rings with a wall thickness <30mm.

Description

Technical Field

[0001] This invention belongs to the field of material forming technology, and in particular relates to a method for stacking and rolling thin-walled rings. Background Technology

[0002] With the development of materials science in my country, the requirements for thinner wall thicknesses of large ring components in fields such as aerospace, chemical engineering, and weaponry are becoming increasingly stringent, and the technical requirements are becoming more demanding. Traditional processes such as ring rolling, free forging, and welding can no longer meet customer requirements in terms of yield, cost, and technical specifications, and have some specific drawbacks and problems:

[0003] (1) The microstructure of the material at the weld of the thin-walled ring formed by the roll welding process is different from that of other areas of the part, and the welding stress is large, making it easy to deform.

[0004] (2) Due to the influence of the rolling mill tonnage, the traditional rolling ring wall thickness is generally greater than 60mm. Therefore, when producing rings with a wall thickness of less than 30mm, the material processing allowance is large, the production cost is high, and the material utilization rate is low.

[0005] (3) Due to the influence of free forging press and forming process, free forging process generally produces ring parts with a diameter of less than 1000mm and a wall thickness of more than 100mm, and the single-sided machining allowance is greater than 15mm, making it almost impossible to produce ring parts of difficult-to-deform alloys such as titanium alloys and high-temperature alloys.

[0006] For alloys that are difficult to deform, such as titanium alloys and high-temperature alloys, a low-cost and efficient forming method is needed to produce thin-walled rings with a wall thickness of less than 30 mm and a diameter of more than 1000 mm. Therefore, this invention provides a stacking and rolling forming method for thin-walled rings to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a method for forming thin-walled rings by stacking and rolling. Through forming steps such as fitting, welding, heating, rolling, end face turning, extrusion, and bulging, it is possible to form rings with a wall thickness of <30mm and a diameter of >1000mm by stacking and rolling. It is especially suitable for the production of thin-walled rings made of difficult-to-deform alloys such as titanium alloys and high-temperature alloys. This method solves the problems of low yield and high welding stress in existing ring forming methods when producing thin-walled rings with a wall thickness of <30mm.

[0008] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution:

[0009] This invention relates to a method for stacking and rolling thin-walled rings, comprising the following steps:

[0010] S1: Matching, based on the weight and size of the final thin-walled ring, design and manufacture the inner ring body, outer ring body and composite layer according to the principle of constant weight and height, and assemble the inner ring body, outer ring body and composite layer together to form a complete ring;

[0011] S2: Heating, heating the assembled ring according to the heating process and keeping it at a certain temperature, the holding time is 30 to 60 minutes longer than the heating time of conventional materials;

[0012] S3: Ring rolling, the heated ring is placed on the rolling mill for rolling, and the thickness of the rolled ring is more than twice the wall thickness of the finished ring;

[0013] S4: Machine the end face, clean the weld joints on the upper and lower end faces of the rolled ring, so that the inner ring body and the outer ring body are separated in the longitudinal direction.

[0014] S5: Press out the ring part by using a free forging hydraulic press to press the inner ring body out from the outer ring body;

[0015] S6: Expansion forming, the inner and outer rings are preheated and expanded using an expansion forming machine to ensure that the inner and outer rings have the same dimensions, and then heat treatment is performed;

[0016] S7: Machining and delivery. Machining the inner and outer rings after bulging and heat treatment according to customer requirements to obtain two finished ring parts and delivering them.

[0017] Furthermore, after the inner ring, outer ring, and composite layer in S1 are assembled, the outer diameter of the inner ring is 0.5 to 1.5 mm larger than the inner diameter of the outer ring minus the thickness of the composite layer.

[0018] Furthermore, when preparing the composite layer in S1, based on the materials of the inner and outer rings, one of stainless steel plate, copper plate, aluminum plate or composite plate is selected, with a thickness of 3 to 5 mm, and refractory cement and graphite emulsion are evenly coated on both sides of the composite layer.

[0019] Furthermore, when using the hot fitting process in S1, the outer ring body is first preheated to 200-600°C, then the composite layer is welded between the inner and outer ring bodies, and finally the upper and lower end faces of the welded inner and outer ring bodies are ground smooth.

[0020] Furthermore, in S3, the rolling deformation is 25% to 50%, and the rolling widthening speed is 1 mm / s to 15 mm / s.

[0021] Furthermore, the extrusion speed in S5 is 1 to 5 mm / s; during extrusion, three or more outer pads are evenly distributed around the circumference at the bottom of the outer ring, and three or more inner pads are evenly distributed around the circumference at the top of the inner ring.

[0022] Furthermore, the preheating temperature of the inner and outer rings in S6 is 40–60°C below the ring phase transformation temperature.

[0023] Furthermore, in S6, the bulging deformation of the inner ring is less than 3%, and the bulging deformation of the outer ring is less than 1%; the widening speed during bulging is 0.5 to 15 mm / s, the dimensional tolerance after bulging is less than 5 mm, and the dimensions of the inner and outer rings are consistent after bulging, with a tolerance of less than 5 mm.

[0024] The present invention has the following beneficial effects:

[0025] 1. This invention, through forming steps such as fitting, welding, heating, rolling, face turning, extrusion, and bulging, can achieve the rolling forming of rings with a wall thickness of <30mm and a diameter of >1000mm, and is especially suitable for the production of thin-walled rings made of difficult-to-deform alloys such as titanium alloys and high-temperature alloys.

[0026] 2. The forming method of the present invention increases the material yield by more than 25%, and the material processing allowance can be reduced to 7.5-9mm on one side, which solves the problems of low yield and high welding stress in the existing ring forming method when producing thin-walled rings with a wall thickness of <30mm. Attached Figure Description

[0027] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a structural diagram for assembly.

[0029] Figure 2 This is a schematic diagram of the structure after ring rolling;

[0030] Figure 3 This is a schematic diagram of the structure behind the end face of the vehicle;

[0031] Figure 4 This is a schematic diagram of the structure during the pressing of the ring.

[0032] The attached diagram lists the components represented by each number as follows:

[0033] 1. Inner ring; 2. Outer ring; 3. Composite layer; 4. Inner pad; 5. Outer pad. Detailed Implementation

[0034] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0035] Please see Figures 1 to 4 As shown, this invention is a method for stacking and rolling thin-walled rings. Taking the production of a P91 ring with a wall thickness of 30mm as an example, the method includes the following steps:

[0036] S1: Based on the final weight and dimensions of the thin-walled ring component, design and manufacture the inner ring body 1, outer ring body 2, and composite layer 3, adhering to the principle of constant weight and height. Assemble the inner ring body 1, outer ring body 2, and composite layer 3 together to form a complete ring component. Specifically, manufacture one P91 tube blank with dimensions Φ585 / Φ430*500mm for the inner ring body 1, and one P91 tube blank with dimensions Φ675 / Φ585*500mm for the outer ring body 2. The blank gap is 2.5mm, the chemical composition of P91 alloy meets ASTM requirements, a 3mm stainless steel plate is placed in the middle of the tube blank, one side of the stainless steel plate is evenly coated with refractory cement, and the other side is evenly coated with graphite lubricating emulsion, rolled into composite layer 3, and assembled using a hot fitting process. First, the outer ring body 2 is preheated to 200-600℃, then the composite layer 3 is welded between the inner ring body 1 and the outer ring body 2, and finally the upper and lower end faces of the welded inner ring body 1 and outer ring body 2 are ground flat.

[0037] S2: Heating, heating and holding the assembled ring according to the heating process, the holding time is 30-60 minutes longer than the heating time of conventional materials, specifically heating the tube blank to 1180℃ and holding for 120 minutes;

[0038] S3: Ring rolling. The heated ring is placed on a rolling mill for rolling. The thickness of the rolled ring is more than twice the wall thickness of the finished ring. The rolling deformation is 25% to 50%, and the rolling width expansion speed is 1 mm / s to 15 mm / s. Specifically, the ring is rolled on a 500T ring rolling mill to a wall thickness of 60 mm, i.e., the size is Φ1100 / Φ980*500 mm.

[0039] S4: Machine the end face, clean the weld joints on the upper and lower end faces of the rolled ring, so that the inner ring body 1 and the outer ring body 2 are separated in the longitudinal direction.

[0040] S5: Press out the ring parts. Using a free forging hydraulic press, press out the inner ring 1 from the outer ring 2 at a speed of 1-5 mm / s. During pressing, three or more outer pads 5 evenly distributed around the circumference are set at the bottom of the outer ring 2, and three or more inner pads 4 evenly distributed around the circumference are set at the top of the inner ring 1. Specifically, the inner ring 1 is pressed out from the outer ring 2 on a 260MN free forging hydraulic press to obtain two ring parts.

[0041] S6: Expansion forming. The inner ring 1 and outer ring 2 are preheated at a temperature 40-60°C below the phase transformation temperature of the rings. They are then expanded using an expansion forming machine to ensure that the inner ring 1 and outer ring 2 have consistent dimensions. After expansion, they are subjected to heat treatment. The expansion deformation of the inner ring 1 is less than 3%, and the expansion deformation of the outer ring 2 is less than 1%. The expansion speed is 0.5-15 mm / s. The dimensional tolerance after expansion is less than 5 mm. Specifically, the inner ring 1 and outer ring 2 are preheated to 1000°C and then expanded to Φ1110 / 1050*420 mm using an expansion forming machine before heat treatment.

[0042] S7: Machining and delivery. Machining the inner ring 1 and outer ring 2 after bulging and heat treatment according to customer requirements to obtain two finished ring parts and delivering them. Specifically, machining the inner ring 1 and outer ring 2 to the finished size of Φ1095 / 1065*410mm.

[0043] This invention enables the rolling forming of rings with a wall thickness of <30mm and a diameter of >1000mm through forming steps such as fitting, welding, heating, rolling, end face turning, extrusion, and bulging. It is especially suitable for the production of thin-walled rings made of difficult-to-deform alloys such as titanium alloys and high-temperature alloys. It solves the problems of low yield and high welding stress in the production of thin-walled rings with a wall thickness of <30mm by existing ring forming methods.

[0044] The above are merely preferred embodiments of the present invention and do not limit the present invention. Any modifications, equivalent substitutions, or improvements made to the technical solutions described in the foregoing embodiments, or to some of the technical features, shall fall within the protection scope of the present invention.

Claims

1. A method for forming thin-walled rings by stacking and rolling, characterized in that, Includes the following steps: S1: Matching, according to the weight and size of the final thin-walled ring, design and manufacture the inner ring body (1), outer ring body (2) and composite layer (3) according to the principle of constant weight and height, and assemble the inner ring body (1), outer ring body (2) and composite layer (3) together to form a complete ring; S2: Heating, heating the assembled ring according to the heating process and keeping it at a certain temperature, the holding time is 30 to 60 minutes longer than the heating time of conventional materials; S3: Ring rolling, the heated ring is placed on the rolling mill for rolling, and the thickness of the rolled ring is more than twice the wall thickness of the finished ring; S4: Machine the end face, clean the weld joints on the upper and lower end faces of the rolled ring, so that the inner ring body (1) and the outer ring body (2) are separated in the longitudinal direction. S5: Press out the ring part by using a free forging hydraulic press to press out the inner ring (1) from the outer ring (2); S6: Expansion forming, preheating the inner ring (1) and outer ring (2) and expanding them through an expansion forming machine to make the inner ring (1) and outer ring (2) have the same size, and then heat treatment is performed; S7: Machining and delivery. Machining the inner ring (1) and outer ring (2) after bulging and heat treatment according to customer requirements, and delivering the two finished ring parts.

2. A method of forming a thin-walled ring by co-rolling of a ring blank according to claim 1, characterized in that After the inner ring (1), outer ring (2) and composite layer (3) in S1 are assembled, the outer diameter of the inner ring (1) is 0.5 to 1.5 mm larger than the inner diameter of the outer ring (2) minus the thickness of the composite layer (3).

3. A method of forming a thin-walled ring by co-rolling of a ring blank according to claim 1, characterized in that When the composite layer (3) in S1 is made, based on the material of the inner ring (1) and the outer ring (2), one of stainless steel plate, copper plate, aluminum plate or composite plate is selected, and the thickness is 3 to 5 mm. Refractory cement and graphite emulsion are evenly coated on both sides of the composite layer (3).

4. A method of forming a thin-walled ring by co-rolling of a ring blank according to claim 1, characterized in that When the hot fitting process is used in S1, the outer ring body (2) is first preheated to 200-600°C, and then the composite layer (3) is welded between the inner ring body (1) and the outer ring body (2). Finally, the upper and lower end faces of the welded inner ring body (1) and outer ring body (2) are polished flat.

5. A method of forming a thin-walled ring by co-rolling of a ring blank according to claim 1, wherein The rolling deformation in S3 is 25% to 50%, and the rolling widthening speed is 1 mm / s to 15 mm / s.

6. A method of forming a thin-walled ring by co-rolling of a blank according to claim 1, wherein The extrusion speed in S5 is 1-5 mm / s; During extrusion, three or more outer pads (5) are evenly distributed along the circumference at the bottom of the outer ring (2), and three or more inner pads (4) are evenly distributed along the circumference at the top of the inner ring (1).

7. A method of forming a thin-walled ring by co-rolling of a ring blank according to claim 1, wherein The preheating temperature of the inner ring (1) and outer ring (2) in S6 is 40-60°C lower than the ring phase transformation temperature.

8. A method of forming a thin-walled ring by co-rolling of a ring blank according to claim 1, characterized in that The bulging deformation of the inner ring (1) in S6 is less than 3%, and the bulging deformation of the outer ring (2) is less than 1%. The expansion speed during bulging is 0.5 to 15 mm / s, and the dimensional tolerance after bulging is less than 5 mm. The inner ring (1) and outer ring (2) have the same dimensions after bulging, and the tolerance is less than 5 mm.

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