CN100431775C - Fast precise semi-axle casing extruding formation process - Google Patents

Abstract

A new process of fast and precise forming of half-shaft casing is proposed. The process is to complete the whole forming task by going through four processes of upsetting, punching, piercing, forward extrusion and upsetting extrusion on the round bar heated to the forging temperature. The precision of the forgings reaches or exceeds the precision level specified in the national standard GB12362 "Steel Die Forgings Tolerance and Machining Allowance". Only four processes are used to complete the production of this kind of transparent hollow hard-to-form forgings, realizing the precision of the half shaft casing. Rapid forming of forgings. The present invention adopts a combined punch structure, and combines punching and skinning with forward extrusion into one process, realizes the hollow rod part formed by forward extrusion, and overcomes the large slenderness ratio of the punch in reverse extrusion, easy deformation, and low service life The disadvantages, improve production efficiency and material utilization, have a broad application prospect.

Description

A New Technology of Fast and Precise Extrusion Forming of Half-shaft Sleeve

technical field

The invention belongs to the field of metal plastic forming in material processing engineering. It is used to form the half-shaft sleeve (shaft head) and its similar hollow shaft forgings.

Background technique

Half shaft bushings are important parts that bear heavy loads on the rear axle of trucks. In order to save fuel consumption, the car is required to increase the load-to-weight ratio, so the lighter weight stamped and welded axle housing is gradually replacing the cast axle housing, and the forged axle sleeve is gradually replacing the cast axle sleeve, so that the axle sleeve and The axle housings are firmly welded together. This is why the demand for forged half-shaft casings has increased significantly year by year in recent years. It is difficult to form and improve the precision of such a slender relatively large hollow transparent forging. At present, there are two main forging processes: one is to use seamless steel pipes for upsetting and extruding on the flat forging machine, and the other is to use round bars for upsetting and extruding, and then set up a separate punching process or a separate end-cutting process to remove the continuous skin . Both of these processes have certain deficiencies. The upsetting and extrusion method of seamless steel pipe cannot form forgings with larger flanges at the end. In addition, the material price is high, the production cost is high, and the application range is shrinking. There are two main problems in the other process: one is that the forming inner hole adopts the reverse extrusion method, the extrusion punch is longer (not less than the height of the forging), the length is relatively large, it is easy to deform during work, and the service life is low. The punches need to be replaced frequently in production, which has become the main factor restricting the increase of productivity; secondly, after the extrusion process, the business needs to set up a separate process to remove the continuous skin left by the reverse extrusion, and sometimes it needs to set up the end cutting process, not only The process is long and the material utilization rate is low.

Contents of the invention

The invention proposes a new fast and precise forming process for the half-shaft casing. The process is to complete the entire forming task by going through the four processes of upsetting, punching, piercing, forward extrusion, and upsetting extrusion on the round bar heated to the forging temperature. . The precision of the forgings reaches or exceeds the precision level in the national standard GB12362 "Steel Die Forgings Tolerance and Machining Allowance". Only four processes are used to complete the production of this transparent hollow hard-to-form forging, realizing the precision of the half shaft casing Rapid forming of forgings.

One of the characteristics of the present invention is to adopt the positive extrusion method to form the hollow rod of the half-shaft sleeve. The positive extrusion punch is composed of an annular punch and a core rod surrounded by the annular punch. The annular punch exerts extrusion force, and the core The rod and the inner wall of the die control the metal flow to ensure the dimensional accuracy of the inner hole and outer wall of the rod. Compared with the reverse extrusion forming rod, the present invention greatly improves the stress state of the extrusion punch, and changes the large slenderness ratio reverse extrusion punch into an annular punch whose height dimension is smaller than the diameter dimension, and the service life of the punch is improved. Increased by more than 10 times, the length of the core rod whose size is similar to the diameter of the reverse extrusion punch is also shortened to about half of the reverse extrusion punch, and the extrusion force is no longer applied, so the wear is greatly reduced, the life is greatly improved, and the inner hole is guaranteed Forming accuracy improves productivity. Another feature of the present invention is that the punching and connecting process and the forward extrusion process are combined into one perforation and forward extrusion composite process, which shortens the process flow, eliminates the separately established punching and connecting process or end cutting process, and improves labor productivity. Improve material utilization, but also reduce production equipment and save investment.

Description of drawings

Accompanying drawing 1 is a kind of semi-shaft sleeve pipe forging figure.

Accompanying drawing 2 is a kind of semi-shaft casing forming process flowchart of the present invention.

Among them 1)-upsetting, 2)-punching, 3)-piercing and forward extrusion, 4)-upsetting extrusion

Accompanying drawing 3 is the die and formwork diagram of perforating and positive extrusion composite process.

Detailed ways

The following examples illustrate the implementation process of the present invention, and further illustrate the technical characteristics of the present invention.

Figure 1 is a diagram of a half-shaft casing forging. The precision grade is the precision grade in GB12362 "Steel Die Forging Tolerance and Machining Allowance". The height of the forging is 380mm, and the head has a flange. Extrusion is used, and the working stroke of the press should be at least twice the height of the workpiece. This is because in addition to the stroke required for extrusion, the stroke required to remove the workpiece after it is ejected from the die must also be considered. In addition to the height of the mold system, the opening height of the press should be greater than 4 times the height of the workpiece. General mechanical presses cannot meet this requirement, but hydraulic presses are easier to meet this requirement, so it is more reasonable to choose hydraulic presses. The four processes of forming forgings can be arranged on three hydraulic presses, and the molds are respectively installed on three sets of mold bases with good guiding precision. Among them, one equipment is used for upsetting and punching, and one equipment is used for piercing, positive extrusion compound process and upsetting extrusion process. Round bar upsetting provides a blank with the right size for the punching process and removes the scale generated by heating at the same time. Closed punching is adopted to ensure the accurate positioning of the blank in the next process and provide good conditions for the forming of the rod. When the piercing and positive extrusion composite process is working, the core rod in the combined punch first removes the punching skin, and the skin falls on the bottom of the die and is blown away by the compressed air, and then the ring punch contacts the blank and applies extrusion force , Through positive extrusion molding, all through the inner hole and outer contour of the rod. Finally, the head flange is formed by upsetting and extruding. Fig. 2 is the process flow, and Fig. 3 is the mold and formwork diagram of the perforating and positive extrusion composite process. The technical features of the present invention are embodied in the perforation and positive extrusion compounding process. Figure 3 clearly shows the working principle of this process. The ring punch exerts extrusion force, and the core rod is responsible for the dual tasks of punching the skin and controlling the flow of metal. Compared with the reverse extrusion punch, the length of the core rod is much shorter and does not bear the extrusion force, but mainly bears the tensile stress caused by friction during work, so the accuracy loss is slower and the service life is longer.

Using a 1250-ton hydraulic press as the main machine and two hydraulic presses with a smaller tonnage to form a production line, it can produce flanges with a diameter of 300 mm, an outer diameter of the rod part of 110 mm, an inner hole of the rod part of 60 mm, and a forging height of 400 mm or less. Half shaft casing. The production cycle is 30 seconds, the shift production can reach 800 pieces, the average weight of forgings is 20 kg, and the shift production of forgings is 16 tons. The material utilization rate of forgings is more than 97%, and the precision of forgings reaches the national standard precision level. The invention is an advanced and practical technology for forging half-shaft casings, and has very broad application prospects.

Claims (2)

1. A new fast and precise extrusion process for half-shaft casing forgings, which is characterized in that the hot-rolled round bar is heated to the forging temperature, and there is no need to set up a separate punching process or head cutting process on the hydraulic press, and the precise and rapid forming is transparent. The process of hole and outer contour is: upsetting-punching-piercing and forward extrusion-upsetting extrusion, the punching is a closed punching, and the piercing and forward extrusion are one process. 2. The new process according to claim 1, characterized in that, in the perforating and forward extrusion process, firstly, the core rod with an appropriate length is used to remove the continuous skin after the closed punching, and then use the forward extrusion Press forming the inner hole, in order to achieve this purpose, a combined punch structure is designed, which is composed of a ring punch and a core rod, the ring punch applies extrusion force, and the core rod is used to form the inner hole.

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