CN112676515B - Die forging forming method and die for marine crank throw - Google Patents
Die forging forming method and die for marine crank throw Download PDFInfo
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- CN112676515B CN112676515B CN202011454552.1A CN202011454552A CN112676515B CN 112676515 B CN112676515 B CN 112676515B CN 202011454552 A CN202011454552 A CN 202011454552A CN 112676515 B CN112676515 B CN 112676515B
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Abstract
The invention provides a die forging forming method and a forming die for a marine crank throw, which comprise a female die for die forging forming and a male die for upsetting a blank in the die, wherein a die cavity matched with the outline shape of a crank throw blank is arranged in the female die; the male dies comprise a first male die, a second male die and a third male die, the first male die is used for extending into the die cavity to carry out in-die upsetting, the second male die is used for extending into the die cavity to carry out stamping operation, and the third male die is used for extending into the die cavity to carry out shaping operation. The male dies used in each stage are separately designed and used in sections, so that the die forging forming force of the crank throw forging piece can be obviously reduced, the die forging forming of the crank throw forging piece can be completed by using a ten-thousand-ton press, the die forging cost of the crank throw is reduced, the formed crank throw forging piece is more ideal in shape, the machining allowance of the die forging crank throw is reduced, and the manufacturing cost is further reduced.
Description
Technical Field
The invention relates to the technical field of forging, in particular to a marine crank throw die forging forming method and a marine crank throw die forging forming die.
Background
The crank throw is an important part of a large and medium-sized marine diesel engine, and is mainly used for crankshafts in large and medium-sized marine (more than ten thousand tons) diesel engines and low-speed two-stroke diesel engines for power generation. The crankshaft is a key part of a large and medium-sized ship, is complex in shape, large in transmission power, capable of bearing alternating load and not allowed to be replaced during the service life of the ship, so that the requirements on the performance of the crankshaft blank forging on the strength, fatigue resistance, impact resistance and the like are very strict.
With the development of shipbuilding industry, the forming method of the bell crank forging piece is continuously innovated, from the initial complete free forging forming to the bending forging forming combining free forging and die forging, the production cost is continuously reduced, the quality of the forging piece is continuously improved, but even then, the manufacturing cost of the bell crank forging piece and the quality of the forging piece still have larger improvement space. Although the existing die forging forming process of the crank throw forge piece realizes the full-fiber manufacturing of the large crank throw forge piece and obviously improves the quality of the forge piece, the maximum die forging forming force is close to four ten thousand tons due to the limitation of the forming process, so that the die forging cost is increased, and the dust is hidden for enterprises with ten thousand ton class presses in China. In addition, two arc end faces of a crank prepared by the existing die forging of the crank forging are formed in a tensile stress state, belong to free surfaces and are also unfavorable for the quality of the forging.
Disclosure of Invention
The invention aims to solve the problems that the existing die forging forming method for the marine crank throw needs larger die forging forming force and increases the manufacturing cost.
In order to solve the problems, the invention provides a die forging forming die for a marine crank throw, which comprises a female die for die forging forming and a male die for upsetting a blank in the die, wherein,
a die cavity matched with the outline shape of the crank hair blank is arranged in the female die;
the male dies comprise a first male die, a second male die and a third male die, the first male die is used for extending into the die cavity to carry out in-die upsetting, the second male die is used for extending into the die cavity to carry out punching operation, and the third male die is used for extending into the die cavity to carry out shaping operation.
Preferably, the female die comprises an outer die, an inner die and two bosses matched with the inner die, the inner die is internally provided with a die cavity matched with the profile shape of the crank hair blank, the two bosses are symmetrically arranged and embedded at the bottom of the inner die along the vertical direction, a first arc-shaped groove is formed between the two bosses, and the inner die and the two bosses are sleeved in the outer die.
Preferably, the second male die comprises a second male die body, a second arc-shaped groove is formed in the working end of the second male die body, and the second arc-shaped groove is matched with the first arc-shaped groove to be suitable for forming a crank pin.
Preferably, the third male die comprises a third male die body, one end of the third male die body is provided with a groove for accommodating the second male die, and the working ends at two sides of the groove are provided with third arc-shaped grooves so as to be suitable for forming the arc-shaped surface of the crank.
Preferably, the depth L of the groove, the fillet radius R of the groove, the height H of the portion of the crank blank exposed after the second male die is punched, and the shaping stroke S of the third male die satisfy the following relationship: l is more than or equal to H + S + R + 200.
Preferably, bosses are arranged on the first male die, the second male die and the third male die on the sides far away from the working end, and the bosses are smoothly connected with the male die bodies to form the male dies with T-shaped sections.
Preferably, the first male die, the second male die and the third male die are all provided with draft angles, and the draft angles are all 2 °.
In order to solve the technical problem, the invention also provides a marine crank throw die forging forming method, based on the marine crank throw die forging forming die, the marine crank throw die forging forming method comprises the following steps:
placing a blank in a female die, and forming a prefabricated blank body with a polyhedral shape in the female die by the blank in an in-die upsetting mode under the action of a first male die;
the prefabricated blank body with the polyhedral shape is subjected to stamping operation under the action of a second male die to form a prefabricated blank body with a groove;
and shaping the free end surface of the prefabricated blank with the groove by using a third male die to form a prefabricated blank with an arc-shaped surface to obtain a crank throw blank, and finely processing the crank throw blank to obtain the crank throw.
Preferably, the height of the preform with a polyhedron shape is raised to the prefabrication height of the bell crank while the preform with a polyhedron shape is subjected to the punching operation by the second male die.
Preferably, after the second male die performs the stamping operation on the prefabricated blank with the polyhedral shape, the second male die is not taken out, the third male die is directly aligned to the free end face of the prefabricated blank with the groove to be extruded until the third male die is completely contacted with the free end face of the prefabricated blank with the groove, and the prefabricated blank with the arc-shaped surface is formed after the pressure maintaining for a preset time.
Compared with the prior art, the invention has the beneficial effects that:
the invention firstly uses the first male die to upset the blank placed in the female die to form a prefabricated blank with polyhedral shape, then uses the second male die to punch the prefabricated blank with polyhedral shape in the female die to form the prefabricated blank with groove, thus obtaining two crank arms and a crank pin of the crank throw, finally uses the third male die to carry out shaping operation on the free end surface of the prefabricated blank with groove in the female die, forms the arc surfaces of the two crank arms of the crank throw, respectively uses different male dies in the three stages (three stages of upsetting, punching and shaping) of the forming crank throw, and obviously reduces the forming force of the crank throw by separately designing and sectionally using the male dies used in each stage, thereby not only using a ten-thousand-ton-grade press to complete the die forging forming of the crank throw forge piece, reducing the die forging cost of the crank throw, but also having more ideal shape of the formed crank throw forge piece, the machining allowance of the die forging crank throw is reduced; in addition, the marine crank throw die forging forming method has the advantages that the free end face of the forged piece is extruded and shaped by the third male die in the last step, so that no free surface exists after the crank throw forged piece is formed, forming under a full-pressure stress state is realized, and the internal quality of the forged piece is improved.
Drawings
FIG. 1 is a process flow diagram of a marine crank throw die forging forming method according to an embodiment of the invention;
FIG. 2 is a schematic view showing an operation state of an in-mold upset blank in an embodiment of the present invention;
FIG. 3 is a schematic perspective view of a female mold according to an embodiment of the present invention;
FIG. 4 is a schematic sectional view of the female mold in the embodiment of the present invention;
FIG. 5 is a schematic front view showing the structure of a first male die according to an embodiment of the present invention;
FIG. 6 is a schematic side view of the first male die in the embodiment of the invention;
FIG. 7 is a schematic front view showing the structure of a second punch in the embodiment of the present invention;
FIG. 8 is a schematic side view of a second male die according to an embodiment of the invention;
FIG. 9 is a schematic front view showing the structure of a third male die according to the embodiment of the present invention;
FIG. 10 is a schematic side view showing the structure of a third male die according to the embodiment of the present invention;
FIG. 11 is a schematic view of the attachment of the hammer carrier to the first punch of the press according to an embodiment of the present invention;
FIG. 12 is a stress distribution cloud of a bell crank forging produced in accordance with an embodiment of the present invention;
fig. 13 is a stress distribution cloud chart of the bell crank forging prepared by the existing die forging forming process of the bell crank forging.
Description of reference numerals:
1-a female die; 2-a male die; 3-blank; 4-a hammer seat; 11-external mold; 12-inner membrane; 13-a boss; 14-a first arc-shaped slot; 21-a first male die; 22-a second male die; 23-a third male die; 211-a first male body; 212-a first boss; 221-a second punch body; 222-a second boss; 223-a second arc-shaped groove; 231-a third punch body; 232-a third boss; 233-grooves; 234-third arc-shaped slot.
Detailed Description
The size and the weight of the crank throw forging piece for the large ship are both large, and according to the approximate calculation formula of the hot die forging forming force, the closed die forging forming of the crank throw forging piece needs about 15 ten thousand tons of forming force, however, the maximum press in the world is 10 ten thousand tons of Italy Gilford company at present, so the closed die forging forming of the crank throw forging piece cannot be realized. However, even when the tire is forged with a small forming force, about 3 million tons of forming force are required, and not only is a large forming force required, but also the cost is high. In addition, two arc end surfaces of a crank prepared by the existing die forging of the crank forging are formed in a tensile stress state, belong to free surfaces and are unfavorable for the quality of the forging.
The technical solutions in the embodiments of the present application will be clearly and exhaustively described below with reference to the accompanying drawings. In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on those shown in the drawings, and are used merely for convenience of description and for simplicity of description, and do not indicate or imply that the device or element so referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus should not be considered as limiting the present invention. Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first" and "second" may explicitly or implicitly include one or more of the described features. In the description of the present invention, "a plurality" means two or more unless specifically defined otherwise.
In the description of embodiments of the present application, the description of the term "some embodiments" means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. Throughout this specification, the schematic representations of the terms used above do not necessarily refer to the same implementation or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
As shown in fig. 2, the embodiment of the present invention provides a die for forming a marine bell crank die forging, comprising a female die 1 for die forging and a male die 2 for upsetting a blank in the die, wherein,
a die cavity matched with the contour shape of the crank hair blank is arranged in the female die 1, and the die cavity is suitable for accommodating the blank 3;
the male die 2 comprises a first male die 21, a second male die 22 and a third male die 23, wherein the first male die 21 is used for extending into the die cavity to carry out in-die upsetting on the blank 3 to form a polyhedral prefabricated blank; the second male die 22 is used for extending into the die cavity to perform the punching operation on the blank 3 to form a prefabricated blank with a groove; the third male die 23 is used for stretching into the die cavity to carry out shaping operation on the free end surface of the blank 3, so as to form a prefabricated blank with an arc-shaped surface, and finally the crank throw hair blank is obtained.
The crank throw blank is prepared by the die forging forming method through the female die and the male die, the deformation of each position can be ensured to be consistent, the components are uniform, the uniformity of mechanical properties of each position is ensured, the quality of products is ensured, in the die forging forming process, different male dies are respectively used when each surface of the crank throw is formed, namely different male dies are respectively used for forming the polyhedral shape of the crank throw, the groove between two crank arms of the crank throw and the arc-shaped surfaces of the two crank arms of the crank throw, by separately designing and sectionally using the male dies used in each stage, the forming force of the crank throw die forging can be obviously reduced, the cost of the crank throw die forging is reduced, and the shape of the formed crank throw forging piece is more ideal, the machining allowance of the forging piece is reduced, in addition, the crank throw forging piece formed by die forging has no free surface, and the quality of the interior of the forging piece is also ensured when the crank throw forging piece is formed in a full-pressure stress state.
As shown in fig. 3-4, in this embodiment, the female die 1 includes an outer die 11, an inner die 12 and two bosses 13 engaged with the inner die 12, a die cavity matched with the profile shape of the crank throw hair blank is provided in the inner die 12, the two bosses 13 are symmetrically disposed along a vertical direction and embedded in the bottom of the inner die 12, a first arc-shaped groove 14 is formed between the two bosses 13 to be suitable for forming a crank throw crank pin preform, and the inner die 12 and the two bosses 13 are sleeved inside the outer die 11. In the embodiment, the two bosses 13 are embedded at the bottom of the inner die 12, and the outer die 11 is sleeved outside the inner die 12 and the two bosses 13, so that the two bosses 13 and the inner die 12 are fastened together, the structure is simple, and the connection and the disassembly are convenient. It should be noted that, when the blank is upset in the mold, when a prefabricated blank with a polyhedral shape is formed, since the two bosses 13 are arranged at the middle position of the bottom of the inner mold 12, and the first arc-shaped groove 14 is formed between the two bosses 13, the shape of the first arc-shaped groove 14 matches with the shape of the crank pin, when the blank is upset in the mold, the crank pin preform of the crank throw is also formed.
As shown in fig. 5 to 6, in the present embodiment, the first punch 21 includes a first punch body 211 and a first boss 212 adapted to be disposed on the first punch body 211, wherein the working end of the first punch body 211 is a plane; the first boss 212 is disposed on one side far away from the working end, the length of the first boss 212 on the side far away from the working end is greater than the length of the first boss 212 on the side close to the working end, and the first boss 212 is smoothly connected with the first male die body 211 so that the cross section of the first male die 21 is T-shaped.
Wherein the first male die 21 is provided with a draft angle A1I.e. both side surfaces of the first male die 21 are inclined surfaces, so that the cross-sectional area of the first male die 21 from the working end surface to a position far away from the working end surface is gradually increased, so that the first male die 21 can enter and leave the female die 1 conveniently. In some preferred embodiments of the invention, the draft angle a of the first male 21 is1Is 2 deg., i.e., the angle between the two inclined surfaces of the first punch 21 and the center line of the first punch 21 is 2 deg..
The working end of the first male die body 211 is a rectangular plane, and the outer diameter of the working end of the lower end of the first male die body 211 is slightly smaller than the diameter of the die cavity, generally speaking, the difference between the outer diameter of the working end of the lower end of the first male die body 211 and the diameter of the die cavity is delta, and delta is 10-15mm, so that locking of the die cavity of the inner die 12 due to thermal expansion of the first male die body 211 during die forging can be avoided, and material turning can be avoided. The person skilled in the art can determine the sizes of the end face of the blank after the integral upsetting in the die to be a0 and b0 according to the principle of volume equality and referring to the result of the numerically simulated upsetting force, and calculate the sizes a1 and b1 of the working end of the first punch body 211 according to the difference delta between the outer diameter of the lower working end of the first punch and the diameter of the die cavity, namely a 1-a 0-2 delta and b 1-b 0-2 delta.
As shown in fig. 7-8, in the present embodiment, the second punch 22 includes a second punch body 221 and a second boss 222 adapted to be disposed on the second punch body 221, wherein the working end of the second punch body 221 is opened with a second arc-shaped groove 223, so as to adapt to the first arc-shaped groove 14 to form a crank pin; the second boss 222 is arranged on the side far away from the second arc-shaped groove 223, the length of the side, far away from the second arc-shaped groove 223, of the second boss 222 is larger than that of the side, close to the second arc-shaped groove 223, of the second boss 222, and the second boss 222 is smoothly connected with the second male die body 221, so that the cross section of the second male die 22 is in a T shape.
It should be noted that in the embodiment of the present invention, the first arc-shaped groove 14 formed between the two bosses 13 is matched with the second arc-shaped groove 223, and when the second punch 22 performs the stamping operation on the blank 3 in the die cavity, the second arc-shaped groove 223 will also stamp on the crank pin preform of the crank throw to form the crank pin, that is, in the embodiment of the present invention, the crank pin is obtained by matching the first arc-shaped groove 14 with the second arc-shaped groove 223 and forming the crank pin during the in-die upsetting operation of the blank 3 by the first punch 21 and the stamping operation of the blank 3 by the second punch 22.
Wherein the second male die 22 is provided with a draft angle a2So that the second punch 22 can enter and exit the female die 1. In some preferred embodiments of the invention, the draft angle A of the second punch 222Is 2 deg..
It should be noted that, the second punch body 221, except that the face connected to the second boss 222 is a non-working end, the rest of the faces are working ends, as shown in fig. 7-8, a2, b2, c2, d2 and e2 are working ends, wherein the size of a2 is the same as the size of a1 of the working end of the first punch body 211, and the sizes of b2, c2, d2 and e2 can be determined by those skilled in the art according to the drawing size of the bell crank forging, the numerically simulated forming force and the press capability, which is not further limited by the present invention.
As shown in fig. 9-10, in the present embodiment, the third punch 23 includes a third punch body 231 and a third boss 232 adapted to be disposed on the third punch body 231, wherein one end of the third punch body 231 is provided with a groove 233 for accommodating the second punch 22, and working ends on two sides of the groove 233 are provided with third arc-shaped grooves 234 for forming arc-shaped surfaces of two crank arms; the third boss 232 is disposed at a side far away from the third arc-shaped groove 234, and the length of the third boss 232 at a side far away from the third arc-shaped groove 234 is greater than the length of the third boss 232 at a side close to the third arc-shaped groove 234, and the third boss 232 is smoothly connected with the second male die body 231, so that the cross section of the third male die 23 is T-shaped.
Wherein the third male die 23 is provided with a draft angle A3So that the third punch 23 enters and exits the female die 1. In some preferred embodiments of the invention, the draft angle a of the third male 233Is 2 deg.. In order to improve the working efficiency of manufacturing the third punch 23 and save the production cost, in some preferred embodiments of the present invention, the draft angle may be provided only at the portion where the third punch 23 contacts the female die 1, and the rest portion is not provided with the draft angle and remains flat.
It should be noted that, except for the non-working end of the surface of the third punch body 231 connected to the third boss 232, the rest of the surfaces are working ends, as shown in fig. 9-10, a3, b3, c3, d3 and e3 are working ends, wherein the size of a3 is the same as the size of a1 of the working end of the first punch body 211, and the sizes of b3, c3, d3 and e3 can be determined by those skilled in the art according to the drawing size of the bell crank forging, the numerically simulated forming force and the press capability, which is not further limited by the present invention.
In order to ensure that the third punch 23 does not collide with the second punch 22 during the process of forming the arc-shaped surfaces of the two crank arms, which affects the service life of the die, it is necessary to ensure that the groove 233 of the third punch 23 has a sufficient depth. For convenience of description, the depth of the groove 233 of the third punch 23 is simply referred to as L, the fillet radius of the groove 233 is R, the height of the portion of the second punch 22 exposed out of the bell crank forging after punching is H, the shaping stroke of the third punch 23 is S, and L is greater than or equal to H + S + R + 200.
In the present embodiment, as shown in fig. 11, the first punch 21 is connected to the hammer holder 4 of the press, and the first boss 212 is snapped into the groove of the hammer holder 4, so that the first punch 21 is connected to the hammer holder 4 of the press. It should be noted that, the second male die 22 and the third male die 23 are connected to the hammer seat 4 of the press in the above manner, forming pressure is provided to the first male die 21, the second male die 22 and the third male die 23 by the press, and in order to facilitate fixing of the first male die 21, the second male die 22 and the third male die 23 by the hammer seat 4 of the press, in some preferred embodiments of the present invention, the joints between each male die body and each boss are provided with chamfers, so as to facilitate clamping the bosses into the grooves of the hammer seat 4. In order to make the connection between the hammer seat 4 of the press and each punch more secure, prevent the punch from falling off during the subsequent upsetting process, and also to achieve the rapid replacement of each punch, in some preferred embodiments of the present invention, a flange (not shown) is further provided on a side of each boss away from the working end, and each boss is fastened to the hammer seat 4 of the press through the flange after being clamped into the groove of the hammer seat 4.
The male die bodies and the bosses are integrally formed, and the male dies are integrally formed, so that the male dies can be used for upsetting the blank in the female die more uniformly, the uniformity of mechanical properties of all parts is ensured, and the risk that the male die bodies and the bosses possibly fall off in the upsetting process is avoided.
The existing free forging press is characterized in that: the movable cross beam only has one action, namely, the loading and the return stroke are realized through the up-and-down movement; in addition, the movable cross beam of the free forging press can be connected with only one male die, so that if the existing free forging press is adopted to finish the press-down forming of a plurality of male dies within one fire, the male dies need to be replaced, and in the process of replacing the male dies, if the male dies cannot be replaced quickly, the temperature of the forge piece can be reduced, the deformation resistance is increased, the forming force is increased, and the pressure of the free forging press is insufficient to form the forge piece. The replacement mode of the upper die hammer head on the press at present is: the hammer head and the hammer seat are fixedly connected in a dovetail and wedge way, the hammer seat is combined with a transverse pin by a vertical pin, and the transverse pin is inserted pneumatically to complete automatic connection with a movable cross beam of the press. The connection mode requires that each hammer head needs to be fixedly connected with one hammer seat in advance, is not suitable for the male die hammer head, and needs to be cast again for three special hammer seats if the connection mode is adopted, so that the production cost is increased. In the embodiment of the invention, bosses which are integrally formed with the punch bodies are arranged on the first punch 21, the second punch 22 and the third punch 23, the cross sections of the punches are T-shaped, the joints of the punch bodies and the bosses are provided with chamfers, flanges are arranged at the joints of the bosses and the press hammer seat 4, the bosses are clamped in the grooves of the press hammer seat 4 and connected with the press hammer seat 4 through the flanges, and the purpose of quickly replacing the punches is achieved. In order to further reduce the cost and facilitate the replacement of the male dies, in some preferred embodiments of the invention, the shape and size of each boss are the same, and the chamfer at the junction of each male die body and each boss is also the same.
The process of replacing the punches by the hammer holder of the press is illustrated by the first punch 21 and the second punch 22:
placing a first male die 21 and a second male die 22 on two different supports respectively, connecting a hammer seat 4 to a movable cross beam of a press, lowering the movable cross beam of the press until the distance between the hammer seat 4 and each boss flange is (0.5-0.6) x (wherein x is the design difference value between the groove depth of the hammer seat 4 and the thickness of each boss flange), keeping the movable cross beam of the press stationary, moving a press workbench, clamping the first male die 21 into the groove of the hammer seat 4, stopping moving the press workbench after the edges of the first male die 21 and the hammer seat 4 are aligned, lifting the movable cross beam of the press, and finishing the connection of the first male die 21 and the hammer seat 4;
after the first male die 21 completes the work task, the movable cross beam of the press falls down, the first male die 21 is moved to the original support, the movable cross beam of the press is lifted upwards by (0.5-0.6) x distance and then kept still, the press workbench is moved to separate the first male die 21 from the hammer seat 4, the press workbench is continuously moved until the second male die 22 is clamped into the groove of the hammer seat 4, the movement of the workbench is stopped, the movable cross beam of the press is lifted, and the connection of the second male die 22 and the hammer seat 4 is completed.
It should be noted that the size of each boss is set according to the size of the inside of the groove of the hammer seat 4, the design difference x between the groove depth of the hammer seat 4 and the thickness of the flange on each boss, and the design difference y between the groove diameter of the hammer seat 4 and the diameter of each boss, and those skilled in the art can adjust the sizes according to actual situations, and the present invention is not limited to this.
As shown in fig. 1-2, S1 in fig. 2 represents the start of in-mold upset, E1 represents the end of in-mold upset, S2 represents the start of in-mold punch, E2 represents the end of in-mold punch, S3 represents the start of in-mold shaping, and E3 represents the end of in-mold shaping. The embodiment of the invention provides a die forging forming method for a marine crank throw, which is based on the forming die and comprises the following steps:
placing the blank 3 in a die cavity of the female die 1, and forming a prefabricated blank body with a polyhedral shape in the female die 1 by adopting an in-die upsetting mode under the action of the first male die 21 on the blank 3;
the prefabricated blank body with the polyhedral shape is subjected to stamping operation under the action of a second male die 22 to form a prefabricated blank body with a groove;
and the third male die 23 performs shaping operation on the free end surface of the prefabricated blank with the groove to form the prefabricated blank with the arc-shaped surface, so as to prepare a crank throw blank, and performs finish machining on the crank throw blank to prepare the crank throw.
The method comprises the steps of upsetting a blank 3 placed in a female die 1 by a first male die 21 to form a polyhedral prefabricated blank, punching the polyhedral prefabricated blank in the female die 1 by a second male die 22 to form the prefabricated blank with a groove, namely obtaining two crank arms and a crank pin of a crank throw, shaping the free end surface of the prefabricated blank with the groove in the female die 1 by a third male die 23 to form the arc-shaped surfaces of the two crank arms of the crank throw, adopting a three-step shaping method in the embodiment of the invention, namely respectively using different male dies in three stages (three stages of upsetting, punching and shaping) of the crank throw, separately designing and sectionally using the male dies used in the stages, reducing the shaping force of each step to within 1.5 ten thousand tons, obviously reducing the die forging shaping force of the crank throw, and realizing the die forging shaping of the crank throw forged piece by adopting the conventional free forging press, the die forging forming of the crank throw forging piece can be completed by using a ten-thousand-ton-level press, the die forging cost of the crank throw is reduced, the formed crank throw forging piece is more ideal in shape, the machining allowance of the die forging crank throw is reduced, and the manufacturing cost is further reduced. In addition, the marine crank throw die forging forming method has the advantages that the third male die 23 is used for extruding and shaping the free end face of the forged piece in the last step, so that no free surface exists after the crank throw forged piece is formed, forming under a full pressure stress state is realized, and the internal quality of the forged piece is improved.
In this embodiment, before the blank 3 is placed on the female die 1, the method further comprises: the blank 3 is heated to 1220-1250 ℃ for a time not less than 1h, and specifically the heating time can be judged and adjusted by those skilled in the art according to the actual situation as long as the heating time is not less than 1h and the blank is convenient to upset and form.
In the embodiment, the blank 3 of the female die 1 is upset by the first male die 21 with the working end being a plane, so that the deformation of each position is consistent, the components are uniform, the uniformity of mechanical properties of each position is ensured, and the improvement of the internal quality of the crank forging is facilitated.
In the embodiment, the first punch 21 is used for upsetting the blank 3, the upsetting stroke is determined according to the size of the crank throw forging, and for the crank throw die forging for the large-scale ship, the upsetting stroke of the blank 3 by the first punch 21 is generally 500-600 mm.
In this embodiment, after the blank 3 is upset by the first male die 21, the first male die 21 is taken out from the female die 1, then the second male die 22 is aligned with the center of the female die 1, the second male die 22 is placed in the female die 1, and the polyhedral prefabricated blank is subjected to the shape punching operation, so that the polyhedral prefabricated blank is subjected to the backward extrusion action during the shape punching operation, the height of the polyhedral prefabricated blank is increased, and the second male die 22 stops the shape punching operation until the height of the polyhedral prefabricated blank is increased to the prefabricated height of the crank, so as to form the prefabricated blank with the groove; it should be noted that the prefabricated height of the crank throw in this embodiment is the height of the crank throw to be achieved according to the process requirements.
In this embodiment, after the second male die 22 performs the stamping operation on the prefabricated blank having the polyhedral shape, the second male die 22 is still placed in the blank, and is not taken out, the third male die 23 is directly aligned to the free end face of the prefabricated blank having the groove and is extruded towards the direction of the free end face of the prefabricated blank having the groove until the third male die 23 is completely contacted with the free end face of the prefabricated blank having the groove, after the pressure maintaining for the preset time, the prefabricated blank having the arc-shaped surface is formed, and the second male die 22 and the third male die 23 are taken out, so that the crank throw blank is obtained.
After the third male die 23 is completely contacted with the free end face of the prefabricated blank body with the groove, the free end face of the prefabricated blank body with the groove is in a full-pressure stress state, and after pressure maintaining preset time, the crank throw die forging is formed under full-pressure stress, so that no free end face exists after the crank throw forged piece is formed, and the quality of the forged piece is improved. In some preferred embodiments of the present invention, the preset dwell time is 3 to 5min, and the dwell pressure is determined according to the pressure of the press, which is not further limited by the present invention.
In the embodiment of the invention, the finish machining of the crank throw rough blank to prepare the crank throw is not further limited, and the skilled person in the art can finish machining the crank throw rough blank according to the actual situation.
In order to further illustrate the present invention, the following examples are given to further illustrate the present invention. The experimental methods used in the examples of the present invention are all conventional methods unless otherwise specified.
Example 1
The embodiment provides a die forging forming method for a marine crank throw, which comprises the following steps:
1.1 heating the blank to 1220-;
1.2 after upsetting is finished, moving a press workbench, moving the female die 1, the prefabricated blank body with the polyhedral shape and the first male die 21 out of the press together, and simultaneously moving a second male die 22 which is placed on the workbench in advance and adjusted in position into the press and connecting the second male die with a hammer seat 4 of the press; moving the second male die 22 away from the female die 1, moving the workbench, moving the female die 1 with the polyhedral prefabricated blank to the lower part of the press, aligning the second male die 22 with the center of the female die 1, pressing the second male die 22 into the polyhedral prefabricated blank, extruding the polyhedral prefabricated blank to enable the height of the polyhedral prefabricated blank to rise until the height of the polyhedral prefabricated blank rises to be consistent with the prefabrication height of the crank throw forge piece, namely, the working stroke of extruding the polyhedral prefabricated blank is 1600mm, and stopping the operation of the second male die 22 to obtain the prefabricated blank with the groove;
1.3, the second punch 22 is still placed in the blank and is not taken out, the press workbench is directly moved, the prefabricated blank with the groove and the female die 1 of the second punch 22 are moved out of the press together, meanwhile, the third punch 23 which is pre-placed on the workbench and adjusted in position is moved into the press and is connected with the hammer seat 4 of the press, the workbench is moved again, the prefabricated blank with the groove and the female die 1 of the second punch 22 are moved to the lower part of the press together, the third punch 23 is aligned with the second punch 22, the third punch 23 is extruded towards the direction of the free end face of the prefabricated blank with the groove until the third punch 23 is completely contacted with the free end face of the prefabricated blank with the groove, namely the stroke of the third punch 23 is 114mm, the prefabricated blank with the arc-shaped surface is formed under the action of the press for 3-5min, the second punch 22 and the third punch 23 are taken out, and (4) obtaining a crank throw rough blank, and performing finish machining on the crank throw rough blank to obtain the crank throw.
Generally, when the hydrostatic pressure is higher, that is, the number of the hydrostatic stresses in the main stress state is higher and the numerical value is higher, the metal is denser, and the final forming quality is better, so that the distribution condition of the hydrostatic pressure in the deformation process is analyzed, the quality condition of each part of the forged piece after forming can be predicted, and the stress distribution cloud chart of the bell crank forged piece shown in fig. 12 is obtained by analyzing the distribution condition of the hydrostatic pressure in the deformation process of the bell crank forged piece manufactured in the embodiment. Fig. 13 is a stress distribution cloud chart of the bell crank forging prepared by the existing die forging forming process of the bell crank forging, and as can be seen from fig. 12 to fig. 13, by adopting the forming method of the embodiment, the internal stress of the prepared bell crank forging becomes more uniform, and the bell crank forging has no tensile stress, which indicates that the quality of the bell crank forging prepared by adopting the forming method of the embodiment is better.
Although the present disclosure has been described above, the scope of the present disclosure is not limited thereto. Various changes and modifications may be effected therein by one of ordinary skill in the pertinent art without departing from the spirit and scope of the present disclosure, and these changes and modifications are intended to be within the scope of the present disclosure.
Claims (9)
1. The die forging forming die for the marine crank throw is characterized by comprising a female die (1) for die forging forming and a male die (2) for upsetting a blank in the die, wherein,
a die cavity matched with the contour shape of the crank hair blank is arranged in the female die (1);
the male die (2) comprises a first male die (21), a second male die (22) and a third male die (23), the first male die (21) is used for extending into the die cavity to perform in-die upsetting, the second male die (22) is used for extending into the die cavity to perform punching operation, the third male die (23) is used for extending into the die cavity to perform shaping operation, the third male die (23) comprises a third male die body (231), one end of the third male die body (231) is provided with a groove (233) for accommodating the second male die (22), and the working ends of two sides of the groove (233) are provided with third arc-shaped grooves (234) so as to be suitable for forming arc-shaped surfaces of crank throws.
2. The die for forming the marine bell crank die forging according to claim 1, wherein the female die (1) comprises an outer die (11), an inner die (12) and two bosses (13) matched with the inner die (12), the inner die (12) is internally provided with the die cavity matched with the contour shape of a bell crank blank, the two bosses (13) are symmetrically arranged along a vertical direction and embedded at the bottom of the inner die (12), a first arc-shaped groove (14) is formed between the two bosses (13), and the inner die (12) and the two bosses (13) are sleeved in the outer die (11).
3. The marine bell crank die-forging forming die as set forth in claim 2, wherein the second male die (22) comprises a second male die body (221), a working end of the second male die body (221) is opened with a second arc-shaped groove (223), and the second arc-shaped groove (223) is matched with the first arc-shaped groove (14) to form a crank pin.
4. The die for die forging of the marine bell crank as set forth in claim 1, wherein the depth L of the groove (233), the radius R of the fillet of the groove (233), the height H of the portion of the bell crank blank exposed after the second punch (22) is punched, and the truing stroke S of the third punch (23) satisfy the following relationship: l is more than or equal to H + S + R + 200.
5. The marine bell crank die forging forming die as set forth in claim 1, wherein the first punch (21), the second punch (22) and the third punch (23) are each provided with a boss on a side away from the working end, and the bosses are smoothly connected with the respective punch bodies to form the respective punches each having a T-shaped cross section.
6. The marine bell crank die forging forming die according to claim 1, wherein the first male die (21), the second male die (22) and the third male die (23) are each provided with a draft angle, and the draft angles are each 2 °.
7. A marine bell crank die forging forming method based on the marine bell crank die forging forming die according to any one of claims 1 to 6, wherein the marine bell crank die forging forming method comprises:
placing a blank (3) in a female die (1), and forming a polyhedral prefabricated blank in the female die (1) by adopting an in-die upsetting mode under the action of a first male die (21) on the blank (3);
the prefabricated blank body with the polyhedron is subjected to stamping operation under the action of a second male die (22) to form a prefabricated blank body with a groove;
and shaping the free end surface of the prefabricated blank with the groove by a third male die (23), forming the prefabricated blank with an arc-shaped surface to obtain a crank throw blank, and performing finish machining on the crank throw blank to obtain the crank throw.
8. The die forging forming method for crank throw for ship according to claim 7, wherein the height of the preform body having a polyhedron shape is raised to the preform height of crank throw while the preform body having a polyhedron shape is subjected to the punching operation by the second punch (22).
9. The marine bell crank die-forging forming method according to claim 7, wherein after the second punch (22) punches the preform having the polyhedral shape, the second punch (22) is not removed, and the third punch (23) is directly pressed against the free end face of the grooved preform until the third punch (23) is completely in contact with the free end face of the grooved preform, and after a predetermined holding time, the preform having the arc-shaped surface is formed.
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| CN202011454552.1A CN112676515B (en) | 2020-12-10 | 2020-12-10 | Die forging forming method and die for marine crank throw |
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| CN202011454552.1A CN112676515B (en) | 2020-12-10 | 2020-12-10 | Die forging forming method and die for marine crank throw |
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| CN112676515B true CN112676515B (en) | 2022-07-15 |
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|---|---|---|---|---|
| CN1616162A (en) * | 2004-09-09 | 2005-05-18 | 武汉重工铸锻有限责任公司 | Process and apparatus for producing large diesel engine crank axle and crank for ship |
| CN2768922Y (en) * | 2004-09-29 | 2006-04-05 | 武汉重工铸锻有限责任公司 | Equipment for producing ship large diesel engine crankshaft crank throw |
| CN105195660A (en) * | 2015-10-16 | 2015-12-30 | 中国兵器工业第五九研究所 | Backward-extrusion active floating concave mold forming system and forming process |
| CN109530605A (en) * | 2018-11-28 | 2019-03-29 | 上海电气上重铸锻有限公司 | A kind of large size crank throw forging apparatus and forging method |
| CN110479939A (en) * | 2019-09-24 | 2019-11-22 | 上海电机学院 | A kind of crank throw forging mold with float type chamber |
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2020
- 2020-12-10 CN CN202011454552.1A patent/CN112676515B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1616162A (en) * | 2004-09-09 | 2005-05-18 | 武汉重工铸锻有限责任公司 | Process and apparatus for producing large diesel engine crank axle and crank for ship |
| CN2768922Y (en) * | 2004-09-29 | 2006-04-05 | 武汉重工铸锻有限责任公司 | Equipment for producing ship large diesel engine crankshaft crank throw |
| CN105195660A (en) * | 2015-10-16 | 2015-12-30 | 中国兵器工业第五九研究所 | Backward-extrusion active floating concave mold forming system and forming process |
| CN109530605A (en) * | 2018-11-28 | 2019-03-29 | 上海电气上重铸锻有限公司 | A kind of large size crank throw forging apparatus and forging method |
| CN110479939A (en) * | 2019-09-24 | 2019-11-22 | 上海电机学院 | A kind of crank throw forging mold with float type chamber |
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