KR101170921B1 - Manufacturing method of a heavy single bodied crankshaft for a ship and a power generation - Google Patents

Abstract

The present invention relates to a method for manufacturing a large integrated crankshaft for ships and power generation, which requires less energy, heats up time faster, and loads into a heating device than conventionally. And a method for manufacturing a crankshaft, which is easy to unload and has excellent linkage with a subsequent die forging process, which greatly improves overall process efficiency.
In the present invention, a method for manufacturing a large integrated crankshaft for ships and power generation, comprising: primary heating the ingot; Free forging the first heated ingot by a hydraulic press to form a rectangular bar shaped body; Molding the square bar shaped body by a hydraulic press to form a round bar shaped body; Forming a preform having a plurality of crank throw material portions formed by cutting the round bar-shaped molded body with a machine tool and having a web material portion located at both sides of the center pin material portion and the pin material portion and having a larger diameter than the pin material portion; The upper body is separated into the upper body and the lower body having a hollow inside, and the upper body is opened and closed upwards, a fireproof material is installed on the inner wall surface, a material charging hole is formed in a corresponding position of the front and rear, and the burner is connected to the fuel supply pipe on the side wall Placing second crank throw material portion of the preform inside a local heating device and then heating it secondly; The crank throw material heated by fixing the secondary heated preform to the upper and lower stator of the die forging device and lowering the pin forming punch and web forming punch attached to the hydraulic press and simultaneously moving the carriage to the center from left and right. Performing a forging of the crank throw by simultaneously performing vertical pressing and left and right pressing operations of the negative pin material portion and the web material portion; Provided is a method of manufacturing a large integrated crankshaft for ships and power generation, characterized in that comprises a.

Description

Manufacturing method of a heavy single bodied crankshaft for a ship and a power generation}

The present invention relates to a method for manufacturing a large integrated crankshaft for ships and power generation, and more particularly, a forged device specially designed after locally heating a preform formed by forging and cutting a steel ingot using a specially designed local heating device. The present invention relates to a method for manufacturing a large integrated crankshaft having a simpler manufacturing process and a superior energy efficiency by forming crank throws in order using the same.

Crankshaft used in large engines for ships and power generation is a kind of power conversion shaft for converting the linear movement of the reciprocating piston into the rotational movement of the propeller, etc. in the engine cylinder. Is manufactured.

1 is a side view of a crankshaft preform for producing an integrated crankshaft, and FIG. 2 is a side view of an integrated crankshaft in which a crank throw is formed.

The integrated crankshaft 20 for ships and power generation is heated to a temperature of about 1250 ℃ to form a round bar shape and then processed again in the shape of the preform 10 as shown in Figure 1 the preform 10 Heated to form a crank throw 23. That is, preliminary rod-shaped preforms in which flange portions 12a and 12b are formed at both side end portions, and a plurality of crank throw material portions 13a to 13f are formed at intermediate portions of the flange portions 12a and 12b. The molded body 10 is heated and forged to manufacture an integrated crankshaft 20 as shown in FIG. 2. A plurality of crank throw 23 of the crankshaft 20 is formed between the flanges 22a, 22b on both sides of the round bar 21 are alternately formed, a plurality of crank throw material portion (13a ~ 13f) shown in FIG. One of them corresponds to one crank throw 23. In the illustrated embodiment, six crank throws 23 are molded from six crank throw material sections 13a to 13f.

The crank throw 23 has a structure in which a web portion 23b is forged on both sides with a central pin portion 23a in a “U” shape. A general method of manufacturing the crank throw 23 having such a shape is to heat the site where the crank throw 23 is to be formed in the preform 10, which is a crankshaft material, to a constant temperature, and then forge the heated preform 10. After being placed in a mold, the punch is lowered to the heating portion of the preform 10 in the state where the pin portion forming punch is attached to the press to firstly form the pin portion 23a of the crank throw. Subsequently, the pin portion forming punch is separated, and then the web portion forming punch is lowered while the web portion forming punch is mounted on the press, and the crank throw is forged by second forming the web portion 23b on both sides of the pin portion.

Applicant's Patent No. 818007, "Buffer Installed in Crankshaft Forging Device," Patent No. 818012, "Crankshaft Forging, for improving the problem of the conventional two-step pin part 23a and web part 23b forming process. Punch to be installed in the device ", Patent No. 81800" Upper and lower fixed locking device is installed in the crankshaft forging mold "is disclosed. The patents incorporated in the present invention are all related to the apparatus for forging the crank throw 23 by processing the heating part of the preform 10 at once by unifying the conventional two-step molding process as the applicant's registered patent. will be.

In order to mold the crank throw 23 of the crankshaft 20 using a conventional process or the above-described patent, it is necessary to locally heat the crank throw material portions 13a to 13f of the preform 10. That is, since one crank throw material portion 13a forms one crank throw 23, it is preferable in the process to heat each crank throw material portion 13a.

Figure 3 is a schematic view showing a state of heating the integrated preform using a conventional induction furnace. As shown in the prior art, an induction heater 30 (Induction Heater) was used to locally heat only one part of the crank throw material portion 13a in the preform 10. The induction heating furnace 30 is a built-in induction heating coil therein for flowing a large current to heat the material to a high temperature in a short time. However, such an induction heating furnace consumes a lot of power, and there is a problem that it cannot be used especially when the preform 10 is above a certain standard. For example, the current induction furnace method has a problem that it can not be applied when the maximum diameter of the round bar 11 of Figure 1 is 460 mm or more.

4 is a schematic diagram of a heating process of an integrated preform according to another conventional example. Due to the problems of the above-described induction heating furnace regarding the heating of the preform 10 of the large integrated crankshaft for ships and power generation, the entire preform 10 of the present invention has a diameter of about 460 mm or more. Adopting legislation. That is, the whole is charged and heated so that the preform 10 is included in the heating furnace 40, and crank throw is formed in a desired part. When one crank throw is formed, the entire preform 10 is again loaded, heated and taken out to form a crank throw in the next order, and the above steps are repeated to complete the formation of the crank throw. In the figure, reference numeral 41 denotes a door of the heating furnace 40, and 42a and 42b indicate a support for supporting the preform 10 loaded.

However, this whole charging method is a waste of energy since the entire material must be heated every time the crank throw 23 is formed, and one crank throw 23 is formed from the crank throw raw material portion 13a of a specific portion. When the material of the adjacent part heated together is rolled into the forging part, the size of the crank throw 23 is not constant and the moldability is deteriorated.

Therefore, in the heating of the preform 10 for manufacturing a large integrated crankshaft, only one crank throw material portion 13a is efficiently heated locally to prevent waste of energy and improve workability of the material. Development was needed.

1. Registered Patent No. 0528085 "Manufacturing Method of Marine Crank Throw Using V-shaped Preform" 2. Registered Patent No. 0418464 "Crank Through Forging Method and Forging Apparatus Using Preform of Unbending Shape" 3. Registered Patent No. 0491538 "Crank through pin part forging method and forging die" 4. Patent No. 0818012 "Punches installed in the crankshaft forging device" 5. Patent No. 0818007 "Buffer installed in the crankshaft forging device" 6. Registered Patent No. 0818008 "Upper and Lower Fixing Locking Device Installed in Crankshaft Forging Mold"

The present invention has been devised to solve the problems of the conventional crankshaft manufacturing process, and in particular, the heating process of the conventional preform takes too long, wastes a lot of energy, and improves the material adverse effects on the crank throw forging process. The purpose.

That is, in the present invention, compared with the conventional preform heating furnace, the energy efficiency is excellent, the heating time is short, the processing efficiency is high, and the local heating apparatus and the localization of the preform can efficiently heat local preforms of various specifications. The present invention aims to provide a method of manufacturing a large integrated crankshaft by using a forging device capable of quickly and accurately forging a heating part.

In order to achieve the above object, in the present invention, a method for manufacturing a large integrated crankshaft for ships and power generation, comprising the steps of: primary heating the ingot; Free forging the first heated ingot by a hydraulic press to form a rectangular bar shaped body; Molding the square bar shaped body by a hydraulic press to form a round bar shaped body; Forming a preform having a plurality of crank throw material portions formed by cutting the round bar-shaped molded body with a machine tool and having a web material portion located at both sides of the center pin material portion and the pin material portion and having a larger diameter than the pin material portion; The upper body is separated into the upper body and the lower body having a hollow inside, and the upper body is opened and closed upwards, a fireproof material is installed on the inner wall surface, a material charging hole is formed in a corresponding position of the front and rear, and the burner is connected to the fuel supply pipe on the side wall Placing second crank throw material portion of the preform inside a local heating device and then heating it secondly; The crank throw material heated by fixing the secondary heated preform to the upper and lower stator of the die forging device and lowering the pin forming punch and web forming punch attached to the hydraulic press and simultaneously moving the carriage to the center from left and right. Performing a forging of the crank throw by simultaneously performing vertical pressing and left and right pressing operations of the negative pin material portion and the web material portion; It is proposed a method of manufacturing a large integrated crankshaft for ships and power generation comprising a.

Here, it is preferable to finish by installing a shielding blanket made of a refractory material between the inner circumferential surface of the material charging hole and the outer circumferential surface of the preform in the second heating step of the crank throw material portion by a local heating device.

At this time, in order to position the crank throw material portion of the preform inside the local heating device, the preform is moved to the upper part of the local heating device by a overhead crane, and then the upper part of the local heating device is opened upward, and the material charging hole is preliminarily opened. The shaft of the molded body is seated and then the open upper body is lowered again to recombine to the lower body.

On the other hand, the step of quenching the crankshaft in which the step of manufacturing the crank throw using the die forging device is completed in a water tank tank (quenching) and then heat-treating in a balance heat treatment furnace (tempering), and the heat treatment of the crankshaft The step of inspecting the dimensions, and the non-destructive inspection of the crankshaft of the dimensional inspection may be further included.

According to the present invention, in order to forge each crank throw of a large integrated crankshaft for ships and power generation, it is not necessary to repeatedly heat the entire preform in a heating furnace every time. It is superior to the process time is shortened, and the part other than the part to be forged is heated, it is possible to prevent the phenomenon that the material of the peripheral portion is rolled to the forged part during the forging molding of the crank throw to generate a dimensional defect.

In addition, since it can be applied to the manufacture of crankshafts of various specifications compared to the conventional electric induction furnace, it is excellent in versatility, and only the crank throw material portion of the preform is loaded into the local heater since the upper body of the local heater is configured to open and close. And the unloading operation is simple and quick.

1 is a side view of a crankshaft preform for producing an integrated crankshaft.
2 is a side view of an integrated crankshaft in which a crank throw is formed.
Figure 3 is a schematic view showing a state of heating the integral preform using a conventional induction furnace.
4 is a schematic view of a heating process of an integrated preform according to another conventional example.
5 is a process block diagram sequentially showing the manufacturing process of the integrated crankshaft for ships and power generation according to the present invention.
Figure 6 is an overall process diagram showing the manufacturing process of the integrated crankshaft for ships and power generation in accordance with the present invention.
7 is an external perspective view of a local heating apparatus of the present invention.
8 is a front view of a local heating apparatus of the present invention.
9 is a longitudinal sectional view of a local heating apparatus of the present invention.
10 and 11 are sectional views of the apparatus for forging a locally heated preform using the forging apparatus of the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail the technical spirit of the present invention.

5 is a process block diagram sequentially showing a manufacturing process of the ship and power generation integrated crankshaft according to the present invention, Figure 6 is an overall process diagram showing a manufacturing process of the ship and power generation integrated crankshaft according to the present invention.

In the following description, a large integrated crankshaft manufacturing method for ships and power generation will be briefly described as a crankshaft manufacturing method for convenience of description.

As shown in Figure 5, the crankshaft manufacturing method of the present invention is largely heating the raw material ingot (heating)-> upsetting-> cogging-> cutting-> normalizing (> normalizing) )-> Preform machining and UT inspection-> local heating-> form forging-> quenching-tempering-> measurement-> process of UT inspection (ultrasonic test) It consists of

Each step described above will be described with reference to FIG. 6 as follows.

First, in the first heating step, the ingot 50 is first heated at a temperature of about 1250 ° C. in the heating furnace 61 (FIGS. 6A and 6B).

In the second step of the offsetting process, the ingot 50 heated to a high temperature is pressed by a forging hydraulic press 62 to form a primary molded body having a smaller diameter and a larger diameter than the ingot 50 as shown in FIG. 51). The process of pressing the heated ingot with the hydraulic press 62 may be performed in one step by attaching a die having a flat plate shape with a large plate surface to the lower portion of the upper mold of the hydraulic press 62 and then pressing it.

In the third step of the cogging process, the outer circumferential surface of the primary molded body 51 is forged freely by the upper mold of the hydraulic press 63, and the secondary molded body 52 whose body is a square bar shape as shown in FIG. ). The upper mold of the hydraulic press 63 used in this process is sufficient to use a general square block type as it is.

In the fourth step, by holding the protrusion 52a of the secondary molded body 52 by using a forceps or the like and freely forging the outer peripheral part thereof, a round bar-shaped tertiary molded body 53 having a circular cross section is formed. It forms (FIG. 6 (e)).

In the fifth step, the protrusion 53a at the tip of the tertiary molded body 53 is cut by a gas torch, etc., and the gas is cut so that the round bar is of a constant length to form a round rod-shaped quaternary molded body 54 (Fig. 6). (F)).

In the sixth step, the quaternary molded body 54 is removed, and the quaternary molded body 54 cut to a predetermined length is normalized. Normalizing is an operation for heating a steel to an austenite range and gradually cooling it in air to condition large crystal structures or deformations.

In the seventh step, the round bar-shaped quaternary molded body 54 cut into a suitable size is cut and processed by a machine tool such as a CNC lathe to form a preform 70 as shown in FIG. . In the preform 70, a plurality of crank throw material parts 73, 74, and 75 are continuously formed in the longitudinal direction, and each crank throw material part 73 is in the center pin material part 73a and the above. It consists of the web material part 73b of both sides of the pin material part 73a. In Fig. 6G, reference numeral 71 denotes a shaft portion having a round bar shape, and 72a and 72b denote flange portions. Here, the diameter of the pin material portion (73a) is formed smaller than that of the web material portion (73b). In addition, the pin material portion 73a and the web material portion 73b may have a cylindrical shape, unlike the illustrated embodiment.

Specific shape of the pin material portion (73a) and the web material portion (73b) can be changed in shape or size or shape depending on the model or size of the crankshaft to be manufactured, but is not necessarily limited to the embodiment shown.

The pin material portion 73a is a portion to be molded into the pin portion 83a in a die forging process using the crankshaft die forging apparatus 200 to be described later, and the web material portion 73b is formed into a web portion 83b. Part. When forging the preform 70 by using the crankshaft die forging apparatus 200 to be described later, the web material portion 73b is pressed from left and right to the center and at the same time, the pin material portion 73a and the web material portion ( 73b) is pressurized from the top to the bottom, and in this case, when the preform 70 is formed as described above, the moldability is excellent and the dimensional accuracy is improved.

In the eighth step, a secondary heating step is performed in which the preform 70 is partially heated to about 1250 ° C. in a local heating device 100 as shown in FIG. 6 (h). The secondary heating process is not performed for the entire preform 70, but locally heats only one crank throw material portion 73 first to forge one crank throw 83, and then a second adjacent crank. It is performed by heating the throw material portion 74.

That is, each of the crank throw material parts 73, 74, 75 of the preform 70 corresponds to one crank throw 83 of the crankshaft 80 to be manufactured. Therefore, in the present invention, the crankshaft 80 is manufactured by repeating the steps of sequentially heating and forging each of the plurality of crank throw material parts 73, 74, and 75 of the preform 70.

The preform 70 is loaded and unloaded into the local heating apparatus 100 or the die forging apparatus 200 to be described later using a ceiling crane. Detailed description of the local heating device 100 will be described later.

In the ninth step, after fixing the preform 70 subjected to the secondary local heating process to the upper and lower fixing brackets (212,214) of the crankshaft forging device 200 of the present invention as shown in Figure 6 (i) Pressing and forging are performed. Details thereof will be described later. The die forging process is repeatedly performed for every crankshaft material portion 73, 74, 75 of the locally heated preform 70.

Through this process, a crankshaft 80 having a crank throw 83 composed of a pin portion 83a and a web portion 83b having a desired shape and size is obtained (Fig. 6 (j)). In Fig. 6 (j), reference numeral 81 denotes a shaft portion having a round bar shape, and 82a and 82b denote flange portions.

Fig. 7 is an external perspective view of the local heating apparatus of the present invention, Fig. 8 is a front view of the local heating apparatus of the present invention, and Fig. 9 is a longitudinal sectional view of the local heating apparatus of the present invention.

As shown, the local heating device 100 of the present invention comprises a lower body 110 largely fixed to the bottom surface and an upper body 120 serving as a lid covering the lower body 110.

The outer wall of the lower body 110 is made of a metal material and a hollow space is formed therein. Refractory material 111 such as a refractory brick or a refractory ceramic is attached to an inner wall surface of the inner space of the lower body 110.

The material loading hemispheres 101a are formed on the front and rear surfaces of the lower body 110 so as to face each other. In this embodiment, the material loading hemispheres 101a have a semicircular shape in a downward direction from the upper end of the lower body 110. It is formed concave. However, the shape of the material loading hemisphere 101a is not limited thereto, and may be concave in a rectangular shape as necessary.

The upper body 120 is mounted on the upper part of the lower body 110 to close the internal space of the local heating apparatus 100 and is similarly formed on the outer wall formed of a metallic material and the inner wall surface of the inner space 121. Is made of.

Like the case of the lower body 110, the material loading hemisphere 101b is also formed at the front and rear surfaces of the upper body 120 to face each other. Here, the material loading hemisphere 101b is also preferably formed in a semicircular shape concave upward from the lower end of the upper body 120, but the shape is not limited thereto.

The material loading hemispheres 101a and 101b respectively formed in the upper body 120 and the lower body 110 are positioned to face each other up and down to form a circular material charging hole 101.

Burners 140 are installed at both sides of the lower body 110, and the burner 140 has a fuel supply pipe 141 and external air for transporting fuel such as LNG to the burner 140 as shown in the burner ( An air blower pipe 144 for supplying to 140 is connected. In the drawings, reference numeral 142 denotes a pressure regulator, and 143 denotes an open / close valve.

At least one temperature sensor 145 is mounted to the side wall of the lower body 110 through the side wall. An exhaust passage 146 for discharging the combustion gas therein is provided on the bottom surface of the lower body 110.

The upper body 120 coupled to the upper end of the lower body 110 is mounted to be opened and closed up and down, and is preferably opened and closed using a hydraulic cylinder 150. That is, after installing the pneumatic pneumatic cylinder 150 on one side of the lower body 120, the upper body 120 connected thereto by the linear movement of the cylinder rod 151 is rotated to open and close. In the present embodiment, the hinge piece 110a and the pivot shaft 153 coupled thereto are mounted at an upper end of one side wall of the lower body 110, and the connecting piece 152 and the upper body 120 coupled to the front end of the cylinder rod 151. Coupling piece (122) connected to the fixed to the hollow tube 154 is coupled to the outer peripheral surface of the rotation shaft (153).

Semi-circular shielding blankets 131 and 132 are mounted on the material loading hemispheres 101a and 101b constituting the material charging hole 101 of the local heating furnace 100, respectively. The shielding blankets (131, 132) is preferably formed of a refractory material such as a ceramic material.

The shielding blankets 131 and 132 are loaded with a preform into a local heating device 100 for manufacturing a crankshaft having various diameters so that the heat inside the heating device leaks through the material charging hole 101 when the local heating is performed. In order to prevent this, the pair is mounted to face each other up and down.

The upper and lower shielding blankets 131 and 132 are formed with arc-shaped grooves 131a and 132a, respectively, so as to be fitted to the outer circumferential surface of the round shaft-shaped shaft portion 71 of the preform 70 when positioned up and down to face each other. It is preferable. Therefore, when the diameter of the shaft portion 71 of the preform 70 is different, the sizes of the shielding blankets 131 and 132 may be replaced with those corresponding thereto.

In FIG. 8, reference numerals 161 and 162 denote heat sinks, which are used to prevent the remaining flame inside the local heating apparatus 100 from affecting the burner 140 when the upper body 120 is opened. In particular, the heat sink 161 located on the left side of FIG. 6 serves to additionally support the load of the upper body 120 when the upper body 120, which is a heavy object, is opened and wetted by the hydraulic cylinder 150. It will be done together.

When the local heating apparatus 100 having such a structure is used, as shown in Fig. 9, the pre-formed portion 70 of the pre-formed crank throw 83 or the crank throw raw material portion 73 to be locally heated is formed. The remaining parts are not heated, which greatly improves energy efficiency.

In FIG. 9, reference numeral 250 denotes a support such as a V-block for supporting both shaft portions of the crankshaft 20 mounted to the local heating device 100. The support is installed on each of the shaft portions of the crankshaft 20 exposed to the outside of both sides of the local heating device (100).

After heating the crank throw material parts 73, 74, 75 one by one in this manner, and repeating the process of forming the crank throw 83 by the crank throw die forging device 200, it is finally shown in FIG. The forging process of the crankshaft 80 having the shape as described above is completed.

10 and 11 are sectional views showing the apparatus forging the locally heated preform by using the forging apparatus of the present invention.

The mold forging device 200 integrated in the present invention is the applicant's registered patent No. 0818012 "Punch installed in the crankshaft forging device", Patent No. 0018007 "Buffer installed in the crankshaft forging device" and registered patent No. 0818008 "Crankshaft forging die is installed in the upper and lower fixed locking device," as described in the present invention, each crankshaft material portion 73, 74 of the preform 70 is cut and locally heated in a special shape And 75 are sequentially forged using the die forging apparatus 200 to form each crank throw 83.

That is, as shown in FIG. 10, the preform 70 is fixed to the upper and lower fixtures 212 and 214, and then mounted on the hydraulic press 250. The pin forming punch 222 and the web forming punch 224 are integrally formed. ), The single crank throw material portion 73 of the preform 70 is forged. At this time, while the hydraulic press 250 descends, the inclined surface of the carriage 216 is pressed to move the carriages 216 on both sides to the center. Accordingly, the punches 222 and 224 press the crank throw material part 73 from the top to the bottom and simultaneously press the crank throw material part 73 from the left and right sides.

The pin portion forming punch 222 has a semi-circular groove portion on the bottom surface of the pin portion forming punch 222 to be in surface contact with the peripheral surface of the pin material portion 73a of the crank throw material portion 73.

On both sides of the pin portion forming punch 222, the web portion forming punch 224 having a vertical length smaller than the pin portion forming punch 222 is formed integrally protruding. The web part forming punch 224 is a punch for forging a web part 83b corresponding to both sides of the pin part 83a to be forged by the operation of the pin part forming punch 222. In detail, the web part forming punch 224 forms a web part 83b corresponding to both sides of the pin part 83a while the pin part forming punch 222 forms the pin part 83a by the pressing operation of the hydraulic press 250. At the same time forging molding. Therefore, unlike the conventional bending forging, the bending and pressing process of several times is not necessary, and thus the crank throw 83 can be formed by only one pressing operation, so that the operation is very quick and the process is simple.

The buffer 226 located below the pin forming punch 222 moves vertically by a rod (not shown), and the pin portion of the crank throw 83 being forged by the operation of the pin forming punch 222. 83a), and means for preventing the deflection of the pin portion 83a. The buffer 226 is rectangular in shape and has a body portion 228 having a semi-circular groove contacting the circumferential surface of the pin material portion 73a of the crank throw material portion 73 to be forged.

The carriage 216 moves horizontally, and moves the upper and lower fixing members 212 and 214 to the center. Accordingly, the upper and lower fixing members 212 and 214 pressurize the crank throw material parts 73 from both sides to the center. .

In the drawings, reference numeral 211 denotes a base of the forging apparatus, and 232 denotes a guide.

When the manufacture of the crankshaft 80 as shown in FIG. 6 (j) is completed through the above process, the crankshaft 80 is immersed in a large water tank for quenching and tempering in a bogie heat treatment furnace. ).

After the heat treatment is completed, the crankshaft 80 is subjected to a dimensional inspection process for checking the dimensional accuracy of the shaft portion 81, the crank throw 83 and the flange portion (82a, 82b) and the like.

Thereafter, a UT test (ultrasonic test) process is performed as a non-destructive test for detecting defects such as pores, cracks, and the like in the tissue of the forged crankshaft 80.

When the non-destructive inspection process is completed, the crankshaft 20 of the finished product as shown in FIG. 2 is finally obtained through the machining and hole cutting processes such as roughing and finishing at each part of the crankshaft 80. .

The present invention relates to a method for manufacturing a large integrated crankshaft for ships and power generation, the short time to heat the material in order to produce a crankshaft, which is usually a heavy weight of more than a ton, energy-efficient, loading and unloading to the heating device The present invention relates to a crankshaft manufacturing method which is convenient for loading and allows a die forging process to be performed quickly. Therefore, the present invention will be able to achieve breakthrough results in terms of energy efficiency and work efficiency when applied in the industry for producing large forging products.

50: ingot 51: primary molded body
52: secondary molded body 53: tertiary molded body
54: quaternary molded body 61: heating furnace
62,63: hydraulic press 70: preform
73, 74, 75: Crank throw material 73a: Pin material
73b: Web Material Division 80: Crankshaft
83: crank throw 83a: pin portion
83b: web
100: local heating device 101: material charging hole
101a, 101b: material loading hemisphere 110: lower body
111: fireproof material 120: upper body
121: fireproof material 131,132: shielding blanket
131a, 132a: arc-shaped groove 140: burner
141: fuel supply line 142: pressure regulator
143: on-off valve 144: air blower
150: pneumatic cylinder 151: cylinder rod
200: forging device 212: upper holder
214: lower holder 216: carriage
222: pin forming punch 224: web forming punch
226: Buffer 228: body
250: hydraulic press

Claims (4)

In the method of manufacturing a large integrated crankshaft for ships and power generation,
Primary heating the ingot;
Free forging the first heated ingot by a hydraulic press to form a rectangular bar shaped body;
Molding the square bar shaped body by a hydraulic press to form a round bar shaped body;
Forming a preform having a plurality of crank throw material portions formed by cutting the round bar-shaped molded body with a machine tool and having a web material portion located at both sides of the center pin material portion and the pin material portion and having a larger diameter than the pin material portion;
The upper body is separated into the upper body and the lower body having a hollow inside, and the upper body is opened and closed upwards, a fireproof material is installed on the inner wall surface, a material charging hole is formed in a corresponding position of the front and rear, and the burner is connected to the fuel supply pipe on the side wall Placing second crank throw material portion of the preform inside a local heating device and then heating it secondly;
The crank throw material heated by fixing the secondary heated preform to the upper and lower stator of the die forging device and lowering the pin forming punch and web forming punch attached to the hydraulic press and simultaneously moving the carriage to the center from left and right. Performing a forging of the crank throw by simultaneously performing vertical pressing and left and right pressing operations of the negative pin material portion and the web material portion;
Method for producing a large integrated crankshaft for ships and power generation comprising a. The method of claim 1,
In the step of second heating the crank throw material portion by a local heating device between the inner circumferential surface of the material charging hole and the outer circumferential surface of the preform to install and close the shielding blanket made of a refractory material, characterized in that large one-piece for ship and power generation Method of manufacturing crankshafts. The method according to claim 1 or 2,
In order to position the crank throw material part of the preform inside the local heating device, the preform is moved to the upper part of the local heating device by a overhead crane, and then the upper part of the local heating device is opened upward, and the preform of the preform is inserted into the material charging hole. The method of manufacturing a large integrated crankshaft for ships and power generation, characterized in that seating the shaft and then down again to open the upper body again to the lower body. The method of claim 3,
Using the die forging device to quench the crankshaft in which the step of manufacturing the crank throw is completed in a water tank, and quench it, and then heat-treat it in a stepwise heat treatment furnace, and measure the dimensions of the crankshaft that is completed. The method of manufacturing a large integrated crankshaft for ships and power generation, characterized in that it further comprises the step of inspecting, non-destructive inspection of the crankshaft of the dimensional inspection is completed.

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