Disclosure of Invention
The invention aims to provide a forging process of a besides-star wheel with a handle, which can uniformly radiate a forged piece and reduce the possibility of cracks of the forged piece.
The technical purpose of the invention is realized by the following technical scheme:
the forging process of the outer star wheel with the handle is used for carrying out sectional cooling treatment on a forged piece and comprises the following processing steps:
firstly, placing a forged forging piece in a cooling box, wherein two rows of fan sets are uniformly arranged on one side of the cooling box in the length direction, and three fans are arranged at equal intervals on each fan set; the models of the six fans are the same;
preliminarily cooling the forge piece, starting a fan positioned at the middle in each exhaust unit, exhausting air in the cooling box for 6-7min, and preserving heat for 2min after exhausting air;
after primary cooling, performing middle-section cooling on the forging, closing fans positioned in the middle of each exhaust unit, opening two fans positioned on the outermost sides of each exhaust unit, exhausting for 4-6min, and preserving heat for 2min after exhausting;
and continuing to cool the rear section of the forging, starting the six fans, exhausting for 3-4min, and keeping the temperature for 2min after exhausting.
By adopting the technical scheme, the forged forging is cooled in sections, so that the internal temperature of the forging can tend to be consistent, the generation of internal stress is reduced, and the possibility of cracks generated in the forging is reduced. The method comprises the following steps that firstly, the fan at the middle is started, the fans at the middle in the two rows of fan sets are close to the upper side and the lower side of a forge piece respectively, through air draft, air flow in a cooling box can be accelerated, the temperature of the surface of the forge piece is taken away, and the two fans can enable air flow passing through the surface of the forge piece to be uniform, so that the temperature of the surface of the forge piece is reduced uniformly. The two fans are insulated after working for 6-7min, the temperature of the outer surface of the forge piece is reduced by a certain range, the temperature inside the forge piece can be transmitted to the surface of the forge piece, and the stress generated inside the forge piece due to overlarge difference of the temperature difference inside and outside the forge piece is avoided. And then the fans on the two sides of the two rows of fan units are opened, the air speed in the cooling box is increased by increasing the number of the fans, so that the cooling speed can be gradually increased, and the cooling effect on the forge piece is further improved. And finally, the wind speed is increased to the maximum, and because the temperature inside and outside the forge piece tends to lower after the forge piece is cooled for the first two times, the wind speed is increased, the forge piece cannot generate stress defect, the cooling speed can be increased, and the working efficiency is improved.
The present invention in a preferred example may be further configured to: before the forging is subjected to cooling treatment, the method further comprises the following steps:
blanking, namely cutting the blank into blanks with required lengths by a shearing machine;
heating, namely heating the blank at the temperature of 980-1000 ℃;
performing sub-hot extrusion, namely performing sub-hot extrusion forming on the forging by adopting a single-point press machine to enable the blank to be processed into the required shape of the forging;
further comprising after the cooling treatment:
and cold finishing, namely performing cold finishing treatment on the forging.
By adopting the technical scheme, the outer star wheel is forged by adopting a sub-hot extrusion means, and the forming temperature is controlled between warm forming and hot forming, so that the method has the advantages of simplifying the process and saving energy. In the forging process, because the heating temperature is low, the process of single normalizing treatment can be eliminated, and the formed product can be cooled by utilizing the preheating control, thereby obtaining excellent internal structure and higher comprehensive mechanical property. The allowance and the oxide skin on the surface of the forged piece are removed by machining after the hot forming in the original process, and the cold-static finishing is adopted at present, so that the flow can be simplified, the deformation of the forged piece is uniform, and cracks are not easy to generate.
The present invention in a preferred example may be further configured to: the wind speed of the fan is kept at a constant speed and is 2-8 m/s.
By adopting the technical scheme, the air flow is uniform due to the uniform air speed, and the heat dissipation effect on the surface of the forging piece is uniform.
The present invention in a preferred example may be further configured to: the gas pumped into the cooling box by the fan is inert gas.
Through adopting above-mentioned technical scheme, let in inert gas in the cooler bin, not only can take away the heat on the forging surface in the cooler bin through the flow of gas, can also reduce the possibility that the oxidation takes place in the forging surface, simplified the process.
The present invention in a preferred example may be further configured to: a first scavenging air box and a second scavenging air box are respectively arranged on two sides of the cooling box; the first air exchange box is communicated with an air inlet of the cooling box; the second air exchange box is communicated with an air outlet of the cooling box; the first air exchange box is connected with the second air exchange box through an air duct; the gas guide pipe is provided with a heat exchanger.
Through adopting above-mentioned technical scheme, set up first scavenging box and second scavenging box, be favorable to realizing cooling gas's circulation for the air current takes away the heat on forging surface, and sets up the heat exchanger on the air duct, can carry out the heat transfer with the gas through the cooler bin, reduces cooling gas's temperature, and the gas temperature when making next circulative cooling can reduce, plays better cooling effect, can also recycle the heat in the cooler bin, environmental protection more.
The present invention in a preferred example may be further configured to: the step of sub-hot extrusion comprises the following specific steps:
in the preforming stage, the blank is processed through a press machine, a convex die and a concave die are arranged on the press machine, when the blank is preformed, the blank is firstly placed in the concave die, the blank is subjected to pre-forging extrusion through the convex die, and the initial forging temperature of the preforming is 950-;
and in the final forging forming stage, the blank is extruded and punched through a male die, so that the blank forms a forging piece with a required shape, the extrusion starting temperature is 910-.
By adopting the technical scheme, the composite forming of the outer star wheel is basically divided into two stages, namely firstly upsetting the head part and reversely extruding the cup part, and then positively extruding the rod part to finally finish the deformation. In the initial cup backward extrusion stage, the blank also moves along with the movement of the male die at the outlet of the taper angle of the female die, when the deformation is carried out to a certain degree, the cup backward extrusion and the stem forward extrusion exist simultaneously, and in the final stage, the deformation is mainly represented as the stem forward extrusion due to the limitation of the male die. In the latter phase of the deformation, the temperature drop is greater due to the contact of the edge of the cup with the punch, the surface temperature being about 774 ℃ at the end of the deformation. Since the metal of the part is not deformed and only moves rigidly, the lower temperature does not have a great influence on the whole deformation. The core of the blank has high deformation speed, the male die has less heat dissipation, and the plastic deformation enables the temperature to rise to some extent, about above 850 ℃, so that better deformation can be ensured. The sub-thermal compound extrusion can achieve the forming effect of parts, and can combine two processes of forward extrusion head and backward extrusion rod into one process, thereby simplifying the process, and achieving the purposes of saving energy, reducing cost and improving efficiency.
The present invention in a preferred example may be further configured to: the inert gas is nitrogen.
Through adopting above-mentioned technical scheme, nitrogen gas is a colorless tasteless gas under the general condition, and nitrogen gas accounts for 78.08% of atmosphere total amount, is one of the principal ingredients of air for because the inertia of nitrogen gas for the difficult oxidation that takes place in forging surface, in addition, nitrogen gas is heat absorption type gas, can take away the heat on forging surface more effectively, reduces the temperature of forging.
The present invention in a preferred example may be further configured to: and in the heating step, a medium-frequency induction heating furnace is adopted to heat the blank.
By adopting the technical scheme, the intermediate frequency heating furnace is used for placing the blank into an inductor, and the inductor is generally a hollow copper pipe for inputting intermediate frequency or high frequency alternating current (300-. The alternating magnetic field is generated to generate induced current with the same frequency in the workpiece, the blank is rapidly heated, and the heating speed can be effectively improved and the possibility of generating oxides on the surface of the blank is reduced due to the small size of the blank.
In conclusion, the invention has the following beneficial effects:
1. in the invention, the forged forging is cooled in sections, so that the internal temperature of the forging can tend to be consistent, the generation of internal stress is reduced, and the possibility of cracks of the forging is reduced;
2. the outer star wheel is forged by adopting a sub-hot extrusion method, and the forming temperature is controlled between warm forming and hot forming, so that the method has the advantages of simplifying the process and saving energy;
3. the inert gas is introduced into the cooling box, so that not only can the heat on the surface of the forged piece in the cooling box be taken away through the flowing of the gas, but also the possibility of oxidation on the surface of the forged piece can be reduced, and the process is simplified.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings.
Referring to fig. 1, which is a flowchart of a forging process of a handled besides-star wheel in an embodiment of the present invention, fig. 2 is a flowchart of a blank in an embodiment of the present invention for performing sub-hot extrusion, fig. 3 is a flowchart of a forging piece in a segmented cooling in an embodiment of the present invention, fig. 4 is a schematic structural diagram of a cooling box 1, and the following detailed description is provided by combining specific steps of the forging process of the handled besides-star wheel in fig. 1 to 4:
s1, blanking, namely cutting the blank into blanks with required length through a shearing machine;
s2, heating, namely heating the blank by adopting an intermediate frequency induction heating furnace, wherein the heating temperature is 980-;
s3, performing sub-hot extrusion, and performing sub-hot extrusion forming on the forging by using a single-point press to enable the blank to be processed into the required forging shape;
s301, in the preforming stage, processing of the blank is achieved through a press machine, a convex die and a concave die are arranged on the press machine, when the blank is preformed, the blank is firstly placed in the concave die, the blank is subjected to pre-forging extrusion through the convex die, the blank is preformed to form a cup-shaped structure, and the initial forging temperature of the preforming is 950-;
s302, in the final forging forming stage, the blank is extruded and punched through a male die, so that the blank forms a forging piece with a required shape, the rod part is positively extruded under the limitation of a die cavity, the die cavity is filled with the blank, the forging piece with the same shape as the forging die is obtained, the extrusion starting temperature is 910-.
S4, cooling in sections, namely, firstly, placing the forged piece into a cooling box 1, uniformly arranging two rows of fan sets on one side of the cooling box 1 in the length direction, and arranging three fans 11 in each exhaust fan set at equal intervals (refer to FIG. 5); the models of the six fans 11 are the same, the wind speed of the fans 11 is kept constant, and the wind speed is 2-8 m/s;
s401, performing primary cooling on the forged piece, starting a fan 11 located at the middle of each exhaust unit, exhausting air in the cooling box 1 for 6-7min, and preserving heat for 2min after exhausting air;
s402, after primary cooling, performing middle-section cooling on the forged piece, turning off fans 11 positioned in the middle of each exhaust unit, starting two fans 11 positioned on the outermost sides of each exhaust unit, exhausting for 4-6min, and preserving heat for 2min after exhausting;
and S403, continuing to cool the rear section of the forging, starting the six fans 11, exhausting for 3-4min, and keeping the temperature for 2min after exhausting.
And S5, cold finishing, namely, carrying out cold finishing treatment on the forge piece, and placing the forge piece into a die of a press machine for forging, so that the size of the forge piece is more accurate.
Referring to fig. 4 and 5, the gas pumped into the cooling box 1 by the fan 11 is an inert gas, preferably nitrogen, which can reduce oxidation of the surface of the forging. A first scavenging air box 2 and a second scavenging air box 3 are respectively arranged on two sides of the cooling box 1. First scavenging box 2 is linked together with the air intake of cooler bin 1, second scavenging box 3 is linked together with the air outlet of the air exhauster 11 of cooler bin 1, and first scavenging box 2 passes through air duct 4 with second scavenging box 3 and is connected, install heat exchanger 5 on air duct 4, a gaseous heat for after will cooling is replaced, make the heat that has the gas of high temperature through cooler bin 1 can be recycled, can reduce the heat of nitrogen gas simultaneously, make nitrogen gas can cool off the forging once more with lower temperature. The heat exchanger 5 preferably adopts a spiral plate type heat exchanger 5, two steel plates which are parallel to each other are coiled into mutually separated spiral flow passages, cover plates are welded at two ends of the spiral plate, and cooling gas and cold water for heat exchange respectively flow in the two spiral flow passages. The heat exchanger 5 has high heat transfer efficiency and high sealing performance, so that the heat exchanger and the heat exchanger are not easy to mix.
The outer star wheel is forged by adopting the sub-thermal composite extrusion process, the head part is upset, the cup part is reversely extruded, then the forward extrusion rod part is finally deformed, the forming effect of parts can be achieved, two processes of forward extrusion of the head part and reverse extrusion of the rod part can be combined into one process, and the process is simplified. After forging, the forging is cooled in sections, so that the internal temperature of the forging can tend to be consistent, the generation of internal stress is reduced, and the possibility of cracks of the forging is reduced.
The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.