CN112439855A - Large step wheel type part forming method - Google Patents

Abstract

The invention discloses a method for forming a large step wheel type part, which comprises the following steps: 1) treating a steel ingot; 2) performing primary forging; 3) finish forging; 4) rolling; 5) the method has the advantages that the method is smooth and punched, a near-net forming method combining forging and rolling is adopted, a formed blank prepared by the method is compact in structure, close to a finished product in shape, free of defects of folding and the like on the surface, small in machining allowance, and capable of greatly improving the finished product rate and the material utilization rate of the wheel.

Description

Large step wheel type part forming method

Technical Field

The invention belongs to the technical field of hot forming of wheel type forgings, and particularly relates to a forming method of a large step type wheel type forging.

Background

In the process of implementing the invention, the inventor finds that the prior art has at least the following problems:

a large, hollow and stepped wheel-shaped part (as shown in figure 1) is one of key parts for railway vehicles, the shape of the part is different from that of a conventional wheel and a conventional wheel rim, the center of the part is hollow, a spoke plate is stepped, no hub part exists, a rim tread can be in various forms such as straight lines, oblique lines and curves, and the outer diameter D range can reach phi 700-phi 1250 mm. Because the shape is special and the service condition is bad, the strict requirement on the manufacturing process is increased, and the manufacturing mode of the large parts mainly comprises the following steps: machining, casting, split welding, die forging, etc., but have the following major problems:

1) the mechanical processing method has high surface precision, but has low production efficiency and serious material waste; and the performance of each aspect of the product can not meet the requirement;

2) the casting method can be used for manufacturing parts with complex shapes, but the casting structure is thick, and the defects of cracks, sand holes and the like exist, so that the product quality is seriously influenced;

3) the welding method can generate defects such as cracks, air holes, impurities and the like, and the defects can seriously affect the fatigue performance of the structure, greatly reduce the structural strength and have huge potential safety hazards;

4) although the traditional die forging method can make up for the performance and manufacturing defects of the process to obtain the die forging with uniform and compact structure, the deformation resistance of the large parts is extremely high, and the requirement on forging equipment is high; and the sharp corners of each part of the forge piece are not fully filled, the machining allowance is large, the material waste is serious, and the forge piece is not suitable for mass production and manufacturing.

Disclosure of Invention

The invention aims to solve the technical problem of providing a large step wheel type part forming method which has compact structure of a prepared forming blank, has a shape close to a finished product, has no defects of folding and the like on the surface, has very small machining allowance and can greatly improve the finished product rate and the material utilization rate of wheels.

In order to solve the technical problems, the technical scheme adopted by the invention is as follows: a method for forming a large step wheel type part comprises the following steps:

1) treating a steel ingot; 2) performing primary forging; 3) finish forging; 4) rolling; 5) and flattening and punching.

In the step 2), the heated billet is placed on a primary forging lower die, and the billet is forged and deformed by a press machine; in the forging process, the billet metal flows along the horizontal direction to fill the primary forging die cavity, and a step type web plate is reserved, so that the metal pre-distribution of the rim and the step type web plate is realized.

And 3) forging and forming the preliminary forging stock by using a forming press to obtain a final forging stock, and forming a pressed spoke plate part of the wheel-shaped piece.

In the step 3), when the finish forging blank is designed, a boss is designed on the inner side of the stepped radial plate, so that metal at the radial plate part can flow when the finish forging is deformed.

In the step 3), the metal of the rim part of the primary forging stock is the finish forging stock rim plus the metal of the rolled spoke plate area.

In the above step 4), the vertical rolling mill for rolling includes: the main roller is in the same shape as the wheel type part tread, the left and right wheel disc rollers drive the wheel blank to rotate in the rolling process, the main roller horizontally moves so as to carry out rolling deformation on a rim area, and the other six rollers are used for the rolling stability of the wheel blank and do not participate in the deformation of a rolled piece.

In the step 5), the rolled blank after rolling and expanding is conveyed to a press machine, and a punch is used for punching the center of the rolled blank; and then, flattening the rim and the stepped radials to eliminate unevenness and distortion of all parts of the wheel-shaped part.

The step 1) comprises the following steps:

a) steel ingot cutting: according to the weight of the fed material of the wheel-shaped part, a disc cold saw or a band saw is adopted to cut the steel ingot to prepare a required steel billet, and the flatness of a cutting surface is ensured by the steel billet after ingot cutting; the feeding weight is equal to the weight of a wheel type part finished product, the processing residual weight, the heating burning loss weight and the punching block weight;

b) heating a steel billet: placing the cut steel billet in a heating furnace for heating to 1250-1300 ℃, wherein the heat preservation time is more than or equal to 4.0 h;

c) descaling: and descaling the heated steel billet by using a high-pressure water device or a mechanical device.

One of the technical schemes has the advantages or beneficial effects that a near-net forming method combining forging and rolling is adopted, the formed blank prepared by the method has compact structure, the shape is close to a finished product, the surface has no defects of folding and the like, the machining allowance is very small, and the finished product rate and the material utilization rate of the wheel can be greatly improved.

Drawings

FIG. 1 is a schematic structural view of a large stepped wheel profile according to the present invention;

FIG. 2 is a schematic view of a roll forming process of the wheel profile of the present invention;

FIG. 3 is a schematic drawing of a wheel form forging die configuration according to the present invention;

FIG. 4 is a schematic representation of a wheel form finish forging die of the present invention;

FIG. 5 is a schematic view of a rolling and expanding structure of the wheel type part;

FIG. 6 is a schematic structural view of a wheel type part flattening and punching die according to the present invention.

The labels in the above figures are: 21. the method comprises the following steps of a primary forging upper die, 22, a primary forging blank, 23, a primary forging lower die, 31, a final forging upper die, 32, a final forging blank, 33, a final forging lower die, 41, a rolling blank, 42, a left web roller, 43, a main roller, 44, a right web roller, 45, a rolling mill central line, 51, a punch, 52, a leveling upper die, 53, a forming blank, 54, a leveling lower die, 55, a jacking sleeve, 56 and a punching block.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Referring to fig. 1-6, a composite forming method of forging and rolling mainly comprises the following steps: the method comprises four working procedures of initial forging, final forging, rolling and flat punching, and comprises the following specific working procedures:

(1) steel ingot cutting: according to the weight of the fed material of the wheel-shaped part, a disc cold saw or a band saw is adopted to cut the steel ingot to prepare the required steel billet, and the flatness of the cut surface of the steel billet after ingot cutting needs to be ensured. The feeding weight is equal to the weight of a wheel type part finished product, the processing residual weight, the heating burning loss weight and the punching block weight;

(2) heating a steel billet: placing the cut steel billet in a high-temperature heating furnace for heating to 1250-1300 ℃, wherein the heat preservation time is more than or equal to 4.0h, so that the steel is completely burnt to reduce the plastic deformation resistance of the wheel-shaped part;

(3) descaling: the heated billet steel needs to be descaled by a high-pressure water device or a mechanical device, the descaling effect is ensured, and the iron oxide scale is prevented from influencing the rolling forming quality of the wheel profile;

(4) initial forging: placing the descaled steel billet on a lower primary forging die by using a manipulator, centering the billet by using a centering device, pressing down by using a press to compress and deform the steel billet, filling a rim part with metal in a horizontal flowing manner, and manufacturing a primary forging blank as shown in 1) in the figure 2, wherein the specific structure of a primary forging die can be seen in figure 3;

and placing the heated billet on a primary forging lower die, and forging and deforming the billet by using a press machine. In the forging process, the billet metal flows along the horizontal direction to fill the primary forging die cavity, and a step type web plate is reserved, so that the metal pre-distribution of the rim and the step type web plate is realized.

(5) Finish forging: placing the primary forging blank in the middle of the finish forging lower die by using a manipulator, centering again, and pressing down the finish forging upper die to fill the rim cavity with the primary forging blank; preparing a finish forging blank as 2) in the figure 2), wherein the inner and outer inner diameters of the finish forging blank are D1 pressure and D2 pressure respectively, and the specific structure of the finish forging die is shown in the figure 4;

and the initial forging stock is forged and formed by a forming press to obtain a final forging stock, so that the pressed spoke plate part of the wheel-shaped part is formed, the metal distribution of the rim is reasonable and sufficient, and the subsequent rolling and expanding are facilitated. When the finish forging blank is designed, a small boss is designed on the inner side of the stepped radial plate, so that metal at the radial plate can flow when the finish forging is deformed, and the resistance to finish forging deformation is greatly reduced, specifically, refer to 2) finish forging blank in fig. 2.

When designing the primary forging and final forging processes, the wheel rim spoke plates can be reasonably distributed according to the capacity of forging equipment. Reasonably designing a forming process, which is beneficial to smooth pressing of a forming press to obtain a perfect outer diameter size of the rim and finish the finish forging; but also is beneficial to the stable rolling forming of the wheel parison in the vertical rolling mill. Namely, the smaller the tonnage of the press, the smaller the deformation of the initial forging and the final forging can be set, and the larger the deformation left on the rolling mill.

Note: and (3) the metal of the rim part of the primary forging blank is the metal of the rim of the final forging blank plus the metal of the rolled spoke plate area.

(6) Rolling and expanding diameter: the structure of the rolling process is shown in fig. 5, and 1 main roller and 2 spoke plate rollers roll and expand the diameter of the finish forging billet. When the expansion amount is L, rolling D1 to D1 + L, and rolling D2 to D2 + L;

when the tonnage of the press is smaller, the D1 pressing and the D2 pressing are set to be smaller, the diameter expansion L is set to be larger when the rolling process is designed, and the capability of forging and pressing equipment can meet the requirements of the rolling process.

As an important process step in the production of the wheel-shaped part, the method has the main functions of rolling and expanding the finish forging blank, enabling the metal at the rim part to flow to the step type wheel disk part, extending the step type wheel disk and finishing the accurate forming of the rim and the wheel disk part. The vertical rolling mill for rolling mainly comprises: the main rollers are in the shape consistent with the shape of the tread of the wheel type part (can be straight lines, curves, oblique lines and the like), the left and right wheel disc rollers drive a wheel blank to rotate, the main rollers horizontally move so as to roll and deform a wheel rim area, and the other 6 rollers are mainly used for the rolling stability of the wheel blank and do not directly participate in the deformation of a rolled piece.

(7) Leveling and punching: as shown in fig. 6, the flat punching die structure is used for carrying out flat and accurate forming on each surface of a rolled blank after rolling and expanding; and punching the rolled blank by using a punch to remove the central block.

Conveying the rolled blank subjected to rolling and expanding to a press machine because the central area of the billet contains more casting defects, and punching the center of the rolled blank by using a punch; and then, flattening the rim and the stepped radial plate to eliminate slight unevenness and distortion of each part of the wheel-shaped part.

The forging and pressing deformation resistance is effectively reduced while the high compactness of the forging and pressing part tissue and the good metal streamline are maintained; the formability is good, and the shape of a formed blank is close to that of a finished product; the machining allowance is very small, and the material utilization rate is greatly improved; the method is suitable for producing and manufacturing large-scale wheel parts with high batch and high efficiency.

By adopting a near-net forming method combining forging and rolling, the formed blank prepared by the method has compact structure, close shape to a finished product, no defects of folding and the like on the surface, very small machining allowance and can greatly improve the finished product rate and the material utilization rate of the wheel.

After the scheme is adopted, the method has the following advantages: (1) the sharp corners of all parts are full, and the shape of the formed blank is close to that of a finished product; (2) the allowance of each part is uniform; (3) the cutting allowance is very small, and the utilization rate of metal materials is greatly improved; (4) the single piece has low manufacturing cost and is suitable for mass production and manufacturing.

The invention has been described above with reference to the accompanying drawings, it is obvious that the invention is not limited to the specific implementation in the above-described manner, and it is within the scope of the invention to apply the inventive concept and solution to other applications without substantial modification.

Claims (8)

1. A method for forming a large step wheel type part is characterized by comprising the following steps:

1) treating a steel ingot; 2) performing primary forging; 3) finish forging; 4) rolling; 5) and flattening and punching.

2. The method of forming a large step wheel type product according to claim 1, wherein in the step 2), the heated billet is placed on a lower die for preliminary forging, and the billet is subjected to forging deformation by a press; in the forging process, the billet metal flows along the horizontal direction to fill the primary forging die cavity, and a step type web plate is reserved, so that the metal pre-distribution of the rim and the step type web plate is realized.

3. A method for forming a large stepped wheel type member as claimed in claim 2, wherein in said step 3), said preliminary forging is press formed by a forming press to obtain a final forging, and said press formed web portion of said wheel type member is formed.

4. A method for forming a large stepped wheel type member as claimed in claim 3, wherein in said step 3), a boss is formed on the inner side of the stepped web in the design of the finish forged blank, so that the metal in the web portion can flow during the finish forging deformation.

5. A method for forming a large step wheel type member as recited in claim 4, wherein in said step 3), the rim portion metal of the preliminary forging is finish forging rim + rolled plate area metal.

6. A method of forming a large stepped wheel profile as claimed in claim 5, wherein in said step 4), the vertical rolling mill for rolling comprises: the main roller is in the same shape as the wheel type part tread, the left and right wheel disc rollers drive the wheel blank to rotate in the rolling process, the main roller horizontally moves so as to carry out rolling deformation on a rim area, and the other six rollers are used for the rolling stability of the wheel blank and do not participate in the deformation of a rolled piece.

7. A method for forming a large stepped wheel profile as claimed in claim 6, wherein in said step 5), the rolled blank after rolling and expanding the diameter is transferred to a press, and the center of the rolled blank is punched by a punch; and then, flattening the rim and the stepped radials to eliminate unevenness and distortion of all parts of the wheel-shaped part.

8. The method of forming a large step wheel type member as claimed in claim 7, wherein said step 1) comprises the steps of:

a) steel ingot cutting: according to the weight of the fed material of the wheel-shaped part, a disc cold saw or a band saw is adopted to cut the steel ingot to prepare a required steel billet, and the flatness of a cutting surface is ensured by the steel billet after ingot cutting; the feeding weight is equal to the weight of a wheel type part finished product, the processing residual weight, the heating burning loss weight and the punching block weight;

b) heating a steel billet: placing the cut steel billet in a heating furnace for heating to 1250-1300 ℃, wherein the heat preservation time is more than or equal to 4.0 h;

c) descaling: and descaling the heated steel billet by using a high-pressure water device or a mechanical device.

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