CN103464674B - A kind of hot forging forming method of duplex fork forging - Google Patents

Abstract

The invention relates to a hot forging forming method of double fork forgings. The good blank is placed on the flat die for upsetting, and the upsetting amount is 15%-25% of the height; the pre-forging is placed in the final forging cavity for final forging; the final forging is placed in the punching and trimming die , punching and trimming to obtain the final forging. The beneficial effects of the present invention are: compared with the welding process after reforming from two standard universal joint yokes, the present invention has short technological process, high material utilization, high production efficiency and low manufacturing cost; compared with casting and forging process , the double-joint fork obtained in the present invention has better mechanical properties due to plastic deformation; compared with the forward split extrusion process, the present invention has simple mold structure, low mold cost and convenient process implementation.

Description

A hot forging forming method for double fork forgings

technical field

The invention relates to the field of metal hot forging forming manufacturing, in particular to a hot forging forming method of a double fork forging.

Background technique

Double fork is a kind of fork-shaped part with complex shape. There are fork-shaped structures with a certain height on both sides of the part. The traditional double-joint fork structure needs to be welded after welding with two standard universal joint forks. The waste of raw materials is serious, the production process is many, the efficiency is low, and the manufacturing cost is high. Zhang Jiali et al. pointed out in the paper "Experimental Analysis of the Improvement of the Transmission Shaft of the Double Fork Structure" (Agricultural Engineering, 2012, 2(2), 90-92) that the casting and forging process is used to form the double fork at one time, which not only increases the strength but also improves the Improve the accuracy and shorten the manufacturing cycle. In the paper "Research on Forward Split Extrusion Technology of Drive Shaft Fork" (Forging Technology, 1991, 16(4), 15-18), Xia Juchen and others proposed to adopt the forward split extrusion process, heating to The bar blank at the initial forging temperature is placed in the closed die chamber of the divisible die, and the bar blank is extruded into a universal joint fork under the action of the punch. This process improves the utilization rate of materials, but it does not involve double fork forgings; moreover, the separable die used has a complicated mold structure. Manufacturing is very difficult.

Contents of the invention

The present invention aims to solve the above-mentioned shortcomings of the prior art, and provides a hot forging forming method for double-fork forgings with high material utilization rate, simple structure of abrasive tools, and stable batch production.

The technical solution adopted by the present invention to solve its technical problem: the hot forging forming method of this double fork forging, the steps are as follows:

(1) Cutting: use round bar sawing and cutting, and the height-to-diameter ratio of the billet is not greater than 1.5;

(2) Preheating the mold: heating the pre-forging mold and the final forging mold to maintain the mold temperature at 200°C to 300°C;

(3) Heating the billet: place the billet in an intermediate frequency furnace and heat it to 1100 ° C ~ 1150 ° C;

(4) Flat die upsetting: put the heated billet on the flat die for upsetting, the amount of upsetting is 15%-25% of the height;

(5) Final forging of flash grooves with unequal height sections: place the pre-forging in the final forging cavity for final forging;

(6) Punching and trimming: the final forging is placed in the punching and trimming die, and punching and trimming are performed to obtain the final forging.

Both the upper die and the lower die of the pre-forging upsetting die have a horizontal section.

The final forging die adopts a vertical mold splitting method. The final forging punch and the final forging die have the same shape and are arranged symmetrically. The flash groove structure of the final forging die adopts the form of flash grooves with unequal cross sections. The edge thickness is larger than the flash edge thickness on one side of the connecting part. The junction of the two unequal height sections adopts a slope transition. The shape and size of the final forging die chamber match the shape and size of the pre-designed double fork final forging hot forging.

The beneficial effects of the present invention are: compared with the welding process after reforming from two standard universal joint yokes, the present invention has short technological process, high material utilization, high production efficiency and low manufacturing cost; compared with casting and forging process , the double-joint fork obtained in the present invention has better mechanical properties due to plastic deformation; compared with the forward split extrusion process, the present invention has simple mold structure, low mold cost and convenient process implementation.

Description of drawings

Fig. 1 is a front view of a forging of a double fork;

Fig. 2 is a side view of a forging of a double fork;

Fig. 3 is the front view of the final forging die of the present invention;

Fig. 4 is a side view of the final forging die of the present invention;

Fig. 5 is a top view of the final forging die of the present invention;

Fig. 6 is a schematic diagram of the unequal section transition of the present invention.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing:

As shown in the figure, the specific steps of the hot forging forming method of this double fork forging are as follows:

(1) Cutting: use round bar sawing and cutting, and the height-to-diameter ratio of the billet is not greater than 1.5;

(2) Preheating the mold: heating the pre-forging mold and the final forging mold to maintain the mold temperature at 200°C to 300°C;

(3) Heating the billet: place the billet in an intermediate frequency furnace and heat it to 1100 ° C ~ 1150 ° C;

(4) Flat die upsetting: put the heated billet on the flat die for upsetting, the amount of upsetting is 15%-25% of the height;

(5) Final forging of flash grooves with unequal height sections: place the pre-forging in the final forging cavity for final forging;

(6) Punching and trimming: the final forging is placed in the punching and trimming die, and punching and trimming are performed to obtain the final forging.

The implementation process requires a set of pre-forging upsetting dies and a set of final forging forming dies. Both the upper die and the lower die of the pre-forging upsetting die have horizontal sections. The final forging die adopts a vertical split mode. The final forging punch and the final forging die have the same shape and are symmetrically arranged. The flash groove structure of the final forging die adopts the form of flash grooves with unequal cross-sections. The thickness of the flash on one side of the fork-shaped forging The thickness of the flash on one side of the connection part is larger, that is, the thickness of the flash on the fork-shaped side of the forging is 4mm to 6mm, which is 2mm to 3mm larger than the thickness of the flash on the side of the connection part. 35mm to 40mm, the shape and size of the final forging die cavity match the shape and size of the pre-designed double fork final forging hot forging.

Example 1

A certain type of transmission shaft double fork, the material is SAE1141 alloy steel, the processing equipment is a 25000kN hot die forging press, and the process is as follows:

1. Blanking: using sharp cutting and blanking method, the blank size is Φ70×100mm;

2. Preheating the mold: heat the upper and lower die chambers of the pre-forging die and the final forging die, and heat the die to 220°C;

3. Heating the billet: place the billet in an intermediate frequency furnace and heat it to 1100°C;

4. Flat die upsetting: Upsetting the heated round bar-shaped blank on the flat die, the amount of upsetting is 20mm.

5. Final forging and forming: place the pre-forging in the final forging die cavity for final forging and forming. The thickness of the flash on one side of the fork is 5mm, and the thickness of the flash on the side of the connecting part is 3mm. The unequal sections of the two flashes adopt a slope transition, and the horizontal width of the slope is 40mm;

6. Punching and trimming: place the final forging in the punching and trimming die, and perform punching and trimming to obtain the final forging.

The forgings obtained in this embodiment are fully filled and high in strength, and no cracks are found after magnetic particle testing.

Example 2

A certain type of transmission shaft double fork, the material is 45 steel, the processing equipment is 25000kN hot die forging press, and the process is as follows:

1. Blanking: using sharp cutting and blanking method, the blank size is Φ70×100mm;

2. Preheating the mold: heating the upper and lower die chambers of the pre-forging die and the final forging die, and heating the die to 250°C;

3. Heating the billet: place the billet in an intermediate frequency furnace and heat it to 1150°C;

4. Flat die upsetting: Upsetting the heated round bar-shaped blank on the flat die, the amount of upsetting is 20mm;

5. Final forging and forming: place the pre-forging in the final forging die cavity for final forging and forming. The thickness of the flash on one side of the fork is 5mm, and the thickness of the flash on the side of the connecting part is 3mm. The unequal sections of the two flashes adopt a slope transition, and the horizontal width of the slope is 40mm;

6. Punching and trimming: place the final forging in the punching and trimming die, and perform punching and trimming to obtain the final forging.

The forgings obtained in this embodiment are fully filled and high in strength, and no cracks are found after magnetic particle testing.

Example 3

A certain type of transmission shaft double fork, the material is SAE1141 alloy steel, the processing equipment is a 25000kN hot die forging press, and the process is as follows:

1. Blanking: using sharp cutting and blanking method, the blank size is Φ70×100mm;

2. Preheating the mold: heating the upper and lower die chambers of the pre-forging die and the final forging die, and heating the die to 250°C;

3. Heating the billet: place the billet in an intermediate frequency furnace and heat it to 1120°C;

4. Flat die upsetting: Upsetting the heated round bar-shaped blank on the flat die, the amount of upsetting is 18mm;

5. Final forging and forming: place the pre-forging in the final forging die cavity for final forging and forming. The thickness of the flash on one side of the fork is 5mm, and the thickness of the flash on the side of the connecting part is 3mm. The unequal sections of the two flashes adopt a slope transition, and the horizontal width of the slope is 40mm;

6. Punching and trimming: place the final forging in the punching and trimming die, and perform punching and trimming to obtain the final forging.

The forgings obtained in this embodiment are fully filled and high in strength, and no cracks are found after magnetic particle testing.

In addition to the above-mentioned embodiments, the present invention can also have other implementations. All technical solutions formed by equivalent replacement or equivalent transformation fall within the scope of protection required by the present invention.

Claims (1)

1. A hot forging forming method of double fork forgings is characterized in that: the specific steps are as follows: (1) Cutting: use round bar sawing and cutting, and the ratio of height to diameter of the blank is not greater than 1.5; (2) Preheating the mold: heating the pre-forging mold and the final forging mold to keep the mold temperature at 200°C to 300°C; (3) Heating the billet: place the billet in an intermediate frequency furnace and heat it to 1100°C to 1150°C; (4) Flat die upsetting: place the heated blank on the flat die for upsetting, the amount of upsetting is 15%-25% of the height, and the upper die and lower die of the pre-forging die all have a horizontal section; (5) Final forging forming of flash grooves with different height sections: the pre-forging is placed in the final forging die cavity for final forging; The dies have the same shape and symmetrical arrangement. The flash groove structure of the final forging die adopts the form of flash grooves with unequal cross-sections. Bevel transition, the shape and size of the final forging die cavity match the shape and size of the pre-designed double fork final forging hot forging; (6) Punching and trimming: the final forging is placed in a punching and trimming die, and punching and trimming are performed to obtain the final forging.