KR101733220B1 - A manufacturing method of cylinder cover and piston crown for a vessel engine, and the piston rod and the connecting rod for the vessel engine manufactured by the manufacturing method - Google Patents

Abstract

The present invention relates to a method of producing a ship engine piston crown, to a method of producing a ship engine cylinder cover, and to a ship engine piston crown and a ship engine cylinder cover produced through the methods. More specifically, in accordance with the present invention, a ship engine component is produced using a slab such that an amount of components discarded in a component production step is able to be minimized. To this end, the present invention provides a method of producing a ship engine piston crown or a ship engine cylinder cover, wherein the method comprises: a step of heating a slab; a step of molding a molded body by performing bloom forging at least once, and upsetting at least once with respect to the heated slab; a step of re-heating the molded body; and a step of performing mold forging using a mold corresponding to an outer appearance of a piston crown to make the reheated molded product have a shape of a ship engine piston crown.

Description

Technical Field [0001] The present invention relates to a method for manufacturing a cylinder cover for a marine engine, a method for manufacturing a piston crown for a marine engine, and a cylinder cover for a marine engine and a piston crown for a marine engine manufactured thereby piston rod and the connecting rod for the vessel engine manufactured by the manufacturing method}

The present invention relates to a method for manufacturing a cylinder cover for a marine engine, a method for manufacturing a piston crown for a marine engine, a cylinder cover for a marine engine and a piston crown for a marine engine manufactured thereby, and more particularly, The present invention relates to an invention capable of minimizing the amount of material discarded during the parts manufacturing process.

For the production of ship parts such as piston rods, connecting rods, cylinder covers and piston crowns, the free forging technique is used.

In the case of free-forging, the ingot weighs about 25 tons or less is heated, and is manufactured by a method such as setting and cogging. A process for manufacturing marine parts by ingot free-forging is disclosed in Korean Patent No. 10-1293631.

In the case of an ingot, a pressurized portion is formed. The pressurized portion reaches 15 to 20% of the total ingot weight. However, since the pressurized portion is not used at the time of actual product molding, there is a problem that material consumption becomes extremely severe.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems and it is an object of the present invention to provide an invention capable of remarkably reducing the cost of parts manufacturing by minimizing the amount of material discarded during the parts manufacturing process for a ship engine.

Another object of the present invention is to diffuse the segregation contained in the piston crown and the cylinder cover to secure the mechanical strength of the piston crown and the cylinder cover and the uniform microstructure therein.

In order to accomplish this object, the present invention provides a method of manufacturing a slab, comprising: heating a slab;

Molding the molded body by performing at least one Bloom forging and at least one at least one setting for the heated slab; Performing reheating for the molded body; And performing a die forging by using a die corresponding to the outer shape of the piston crown and a punch corresponding to the inner shape so that the formed body after the reheating step has the shape of the piston crown for the marine engine. Of the present invention.

And cutting the slab to be heated to a predetermined width, height and length before heating the slab.

The step of shaping the shaped body by performing at least one Bloom forging and at least one or more at least one setting for the heated slab,

Performing a primary blob forging on the heated slab to form a formed body; Performing primary upsetting on a molded body that has undergone primary bloom forging;

And performing cogging forging for mold forging after completion of the first-stage setting.

The reheating step is characterized in that the molded body is heated at a temperature higher than 1,250 ° C to 1,290 ° C for 2 hours to 10 hours.

There is provided a piston crown for a marine engine, which is manufactured by the above-described method for manufacturing a piston crown for a marine engine.

The present invention also relates to a method of manufacturing a slab, comprising: heating a slab; Molding the molded body by performing at least one Bloom forging and at least one at least one setting for the heated slab; Performing reheating for the molded body; And performing mold forging by using an upper punch and a lower punch corresponding to the mold and the inner mold corresponding to the outer shape of the cylinder cover so that the molded product after the reheating step has the shape of the cylinder cover for the marine engine. A method of manufacturing a cylinder cover for an engine is provided.

And cutting the slab to be heated to a predetermined width, height and length before heating the slab.

The step of forming a molded body by performing at least one blot forging and at least one or more times of setting the heated slab by performing a first bloom forging on the heated slab to form a formed body; Performing primary upsetting on a molded body that has undergone primary bloom forging; And performing primary coking for the shaped body subjected to the first upsetting.

The reheating step is characterized in that the molded body is heated at a temperature higher than 1,250 ° C to 1,290 ° C for 2 hours to 10 hours.

And a cylinder cover for a marine engine manufactured by a method for manufacturing a cylinder cover for a marine engine.

According to the present invention, material loss can be minimized by utilizing a slab that can be cut and used as needed as compared with an ingot having a large material loss.

In addition, according to the present invention, the mechanical strength of the product can be increased by effectively minimizing or eliminating voids formed in the component.

Further, according to the present invention, the concentrated segregation in the component can be diffused, which can contribute to an increase in the mechanical strength of the product.

1 (a) is a perspective view of a slab used in the present invention.
Fig. 1 (b) shows a cut-away portion of the slab used in the present invention and primary heating thereon.
Fig. 1 (c) illustrates that primary bloom forging is performed in the present invention.
FIG. 2 (a) shows that the first-epiphoning is performed in the present invention.
Fig. 2 (b) shows that bloom forging or cogging forging is performed after the first upsetting in the present invention.
3 (a) shows reheating in the present invention for producing a cylinder cover.
Fig. 3 (b) shows that the cogging forging is performed on the molded body after reheating in the present invention for producing the cylinder cover.
Fig. 3 (c) to Fig. 3 (d) show that the molded article after reheating is formed inside the mold forming the outer shape of the cylinder cover.
Fig. 3 (e) shows a punch hole formed in the present invention for producing a cylinder cover.
Fig. 3 (f) shows punching holes in the present invention for producing a cylinder cover.
4 (a) shows reheating in the present invention for making a piston crown.
Fig. 4 (b) shows that the cogging forging is performed on the molded body after reheating in the present invention for producing the piston crown.
Fig. 4 (c) shows that the molded article after reheating is formed inside the mold which forms the outer shape of the cylinder cover.
Fig. 4 (d) shows punch holes formed in the present invention for producing a piston crown.
5 is a flowchart according to the present invention.
6 (a) is a perspective view of a piston crown completed by the present invention.
6 (d) is a perspective view of the cylinder cover completed in the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings.

However, it should be understood that the present invention is not limited to the embodiments disclosed herein but may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Also, terms used herein are for the purpose of illustrating embodiments and are not intended to limit the invention.

In the present specification, the singular form includes plural forms unless otherwise specified in the specification. &Quot; comprises "and / or" comprising "used in the specification do not exclude the presence or addition of components other than the components mentioned.

Unless defined otherwise, all terms (including technical and scientific terms) used herein may be used in a sense commonly understood by one of ordinary skill in the art to which this invention belongs.

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

1, a raw material of a piston crown (hereinafter referred to as a 'piston crown') for a marine engine and a cylinder cover for a marine engine (hereinafter referred to as a 'cylinder cover') according to the present invention, It is a slab (1).

The ingot is formed by molten metal casting, while the slab 1 is formed by a continuous casting method, and is characterized by a thin plate shape that is thinner than the ingot.

In the case of the ingot, the pressurized portion is formed. The pressurized portion reaches 15 to 20% of the total ingot weight, but it is discarded because it is not used in actual product molding.

However, the slab 1 used in the present invention has a characteristic that there is almost no discarded portion in the product molding process because the slab 1 is in the form of a continuous body without such a pressing portion.

In order to manufacture the piston crown or the cylinder cover using the slab 1 to be a material, a step of cutting a slab portion into a three-dimensional shape having a predetermined width, length and thickness should first be performed.

Shown in dashed line in FIG. 1 (a), the hatched portion 101 is the object to be cut by the present invention to be used in manufacturing the piston crown or cylinder cover.

The portion of the slab thus cut is initially formed in the shape of a rectangular parallelepiped 102 as shown in Fig. 1 (b). The first heating is performed to form the rectangular parallelopipedal member 102.

In the case of the first heating, the heating is performed at a temperature of about 1,250 ° C to 1,290 ° C for about 15 hours to 20 hours.

When the primary heating is completed, the molded body 103 is formed by performing the primary bloom forging to increase the length of the heated rectangular parallelepiped.

In molding a part using a conventional ingot, the ingot is heated and immediately subjected to the eb setting operation. However, in the case of the slab, the upsetting effect due to buckling is canceled when the eb setting operation is performed.

Therefore, the forging ratio is ensured prior to the application setting and the primary bloom forging is performed to prevent buckling.

For the primary bloom forging, the heated sheet material 102 is placed on a press die using a forklift, and the upper surface of the sheet material is pressed and deformed by using an envelope connected to the press.

Specifically, as shown in Fig. 1 (c), when the flat rectangular sheet material 102 heated in Fig. 1 (b) is placed on the press die and pressed using an envelope, do. The definition of the length L, width W and thickness T is based on the area measured in the slab 102 shown in FIG. 1 (b).

The primary molding is performed as shown in Fig. 2 (a) with respect to the molded body 103 that has been subjected to the primary bloom forging. The abse setting is a free-forging method that increases the diameter (width) and reduces the length (height), and is performed in order to compress the internal voids or pores inside the molded body through the inflection and to secure the forging ratio.

As shown in Fig. 2 (a), after the molded body 103 in which the primary bloom forging is completed is put on the lower die 20 for the setting operation, the upper die 10 is placed on the molded body, Is compressed downward using a press.

In this case, the height (length) is reduced, the diameter (width) is increased, and the outer circumferential surface is inflated with a curved surface. .

When the first-stage setting is completed, the molded body 105 having undergone the first-order setting is subjected to bloom forging or cogging forging to roughly shape the piston crown or the cylinder cover before reheating.

The molded body after bloom forging or cogging forging is represented by reference numeral 105.

Specifically, the molded body subjected to the first upsetting is laid down on the side, and the angular portion on the outer circumferential surface is continuously pressed to transform into a round bar shape.

When bloom forging or cogging forging is completed, reheating is performed as shown in Fig. 3 (a).

The reheating is carried out for a period of from 2 hours to 10 hours in a temperature range from above 1,250 ° C to 1,290 ° C.

The molded body after the reheating process is represented by reference numeral 108.

The reason for performing the first-stage setting and reheating is that the pores are squeezed by the first upsetting, reheated and squeezed, for the diffusion bonding, and the inner segregation (the phenomenon that the chemical components are partially gathered) is uniformly diffused It is for this reason.

Manganese (Mn) and carbon (C) components are contained in the slabs in addition to iron components. Partially, carbon and manganese components locally segregate to form segregation.

There is a problem that breakage occurs when tensile or compressive stress of the piston crown or the cylinder cover occurs when the gap becomes a certain size or more.

In addition, there is a problem that when the pores are generated over a certain size, and when the components such as manganese and carbon are segregated, a defect is judged at the time of product inspection.

In other words, the magnetic particle inspection during the inspection of the product causes electric current to flow on the surface of the component and the component is buried on the surface. If the component is oriented in a certain direction due to the magnetic force, it is judged as defective.

In the absence of air gap and component segregation, the current does not shift in a specific direction, but the current becomes random. When the current meets the pore or component segregation region, the current is bypassed. Lt; / RTI >

Therefore, in order to ensure mechanical strength and pass product inspection, it is also necessary to compress or eliminate the voids or to minimize the voids and diffuse component segregation.

In the case of pores, it can be contracted by the application setting, but in the case of segregation, the above-mentioned alloying elements are gathered, and because of the solid bonding arrangement of Fe atoms, Mn atoms and C atoms, There is a limit to doing.

Therefore, reheating is required.

First, when a physical force is applied to the molded body through the first-stage setting process, Fe atoms surrounding the region where the Mn atoms and the C atoms are attracted move, and a minute hollow space is formed around the Fe atoms.

In this state, the reheating is carried out at a temperature higher than 1,250 ° C. to 1,290 ° C. because the Mn atom can be diffused, and the diffused Mn atoms move to the vacant space generated by the Fe atom transfer and migrate to the C atom locally, .

In the above temperature range, the binding force between the electrons outside the Fe and the electrons outside the Mn weakens, allowing the Mn atoms to migrate.

For reference, in the slab to be a material, Mn is 0.5-1.1% by weight, C is about 0.2-0.4% by weight, and the balance is Fe and other alloying elements.

And it is necessary to perform reheating process for more than 2 hours so that the process of spreading segregation can be continued and stable.

When the reheating process is performed for 2 hours to 10 hours at a temperature in the range of 1,250 to 1,290 ° C., the molded body 110 is pressed by pressing the outer peripheral surface in a state where the molded body is laid down as shown in FIG. 3 (b) The mold forging is performed using the ring mold 40 as shown in Fig. 3 (c). The mold 40 is a mold for forming a cylinder cover.

The mold 40 is composed of a first outer wall 41 and a second outer wall 42.

The inner diameter of the first outer wall 41 is narrower than the inner diameter of the second outer wall 42.

A first space portion 44 surrounded by the first outer wall 41 and a second space portion 43 surrounded by the second outer wall 42 are formed respectively, 2 outer wall 42. In this embodiment,

First, as shown in Fig. 3 (c), the formed body 110 having been subjected to the cogging forging is put into the mold 40, the upper die 10 is covered with the molded body 110, and the veneer 20 is pushed.

The mold 40 is initially supported by a separate supporting device so that the lower surface of the mold 40 is floated. However, due to the downward pressure of the upper die 10 and the envelope 20, Touch the die.

In this state, the formed body 110 has a shape corresponding to the size of the first space portion 44.

That is, the outer diameter of the formed body 110 corresponds to the inner diameter of the first outer wall 41.

The outer surface of the molded body 110 is separated from the inner surface of the second outer wall 42.

In this state, when the upper die 10 is pressed using the press 20, as shown in Fig. 3 (d), as the molded body 110 is pressed, the molded body 110 is pressed against the first space portion 44 and the second And changes according to the shape of the space portion 43.

When the mold body 110 is filled with the internal space of the mold body 40, the inside of the mold body 40 is pressed into the mold body 40 while pressing the mold body 40 upside down, 110).

As shown in Fig. 3 (e), a punch hole 111c is formed in the molded body 111 by using the lower die punch 50. [

When the lower die punch 50 is inserted into the formed body 111, the portion pressed by the lower die punch 50 does not escape to the outside, but moves to the periphery as shown by an arrow. As a result, the structure becomes more dense and the strength is improved.

Reference numeral 111b denotes a portion formed by the first outer wall 41 of the metal mold 40. Reference numeral 111a denotes a portion formed by the second outer wall 42 of the metal mold 40. The outer diameter Particularly, the portion denoted by 111b has a smaller outer diameter than the portion denoted by 111a and is stepped.

The lower die punch 50 forms a punch hole 111c that is blocked with respect to a part of the formed body 111, not a hole penetrating the inside of the molded body 111 up and down.

3 (f), the lower punch 50 is inserted, the upper punch 51 is inserted into the punch hole 111c, and the lower punch 50 is pushed out to pierce the inside of the cylinder cover .

The above process constitutes the basic outer shape and the inner shape of the cylinder cover, and additional heat treatment and mechanical processing are required to specifically form the shape of the cylinder cover.

4 shows a process of manufacturing a piston crown.

4 (a), after the reheating process is performed for 2 hours to 10 hours at a temperature range of 1,250 to 1,290 ° C., the molded body 109 after cogging forging as shown in FIG. 4 (b) The mold forging is performed using the ring-shaped mold 70 as shown in Fig. 4 (c).

When the molded body 109 is placed on the ring-shaped outer mold 70 and pressurized by using the upper die 10 and the envelope 20 as shown in FIG. 4C, the molded body 109 is fitted into the space formed inside the outer mold 70 A formed body 120 having an external shape is formed.

In this way, the inside of the outer mold 70 is filled with the formed body 120 while the inner structure of the formed body 120 is dense.

Then, as shown in Fig. 4 (d), the inner punch 80 is inserted into the upper surface to form the punch hole 131, and the inner punch 80 is shaped like the inner shape of the piston crown.

When this is completed, the basic shape of the piston crown is shown as shown in Fig. 4 (e). That is, a punch hole 131 is formed in the inside, and a round surface is formed so that the upper rim and lower rim of the punch hole 131 have a predetermined R value.

The above process constitutes the basic outer shape of the piston crown, and additional heat treatment and mechanical processing are required to form the shape of the piston crown specifically

5 is a flowchart showing the above-described processes. The above process is briefly summarized as follows.

That is, first, the slab material is cut to prepare a rectangular parallelepiped slab material (S401), and the slab material is primarily heated (S402).

The primary heating is carried out at a temperature of about 1,250 ° C to 1,290 ° C for 15 hours to 20 hours.

Then, when the primary heating is performed, primary bloom forging is performed in order to secure the up-setting ratio in the inflation setting process (S403).

When the primary bloom forging is completed, the primary inflection is performed to compress the voids inside the molded body (S404).

By performing the first-stage setting, the inner cavity is squeezed

As a preliminary work to diffuse concentrated segregation through the first-order setting, void spaces can be formed between Fe atoms so that Mn atoms or C atoms, which are locally flocked alloys, can move and diffuse.

Thereafter, bloom forging or cogging forging is selectively performed (S405), and a reheating process is performed (S406).

As described above, in the case of the reheating step, the reaction is carried out at a temperature of 1,250 ° C to 1,290 ° C within a range of 2 hours to 10 hours.

In the above temperature range, Mn can diffuse, and Mn atoms and C atoms can diffuse into void spaces formed between Fe atoms, and segregation concentration can be solved.

After the reheating is completed, the mold forging is performed to form the shape of the piston crown or the cylinder cover (S407)

In the mold forging process, the punch hole forming process is included, and the piston crown and the cylinder cover can make the internal structure more denser by forming the punch hole.

Thereafter, heat treatment such as normalizing and tempering is performed (S408). Thereafter, the piston crown as shown in Fig. 6 (a) or the cylinder cover as shown in Fig. 6 (b) is manufactured and supplied through mechanical processing thereafter.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be appreciated that one embodiment is possible.

Accordingly, the true scope of the present invention should be determined by the technical idea of the claims.

1: Slabs 40, 70: Mold
50, 60, 80: punch 111c, 131: punch hole

Claims (12)

Cutting the slab to a predetermined size;
Heating the cut slab;
Molding the molded body by performing at least one Bloom forging and at least one at least one setting for the heated slab;
Performing reheating for the molded body;
And performing mold forging by using a die corresponding to the outer shape of the piston crown so that the formed product after the reheating step has the shape of the piston crown for the ship engine and using the die punch corresponding to the inner diameter of the piston crown,
The step of molding the molded body by performing at least one bloom forging and at least one upsetting on the heated slab,
Performing a primary bloom forging to increase the thickness and length while decreasing the width for the heated slab to form a formed body;
Performing primary upsetting such that the length of the primary bloom forging is raised and the length thereof is arranged in the up and down direction, and the formed body is compressed downwardly so that the length is reduced and the width is increased;
The molded body subjected to the first upsetting is laid down so that the length thereof is in the horizontal direction and the second bloom forging or the first cogging forging is performed in which the angled portions on the outer circumferential surface are pressed so as to be in a round bar state, Or the primary cogging forging is performed after the completion of the first upset and before the reheating step
Wherein the reheating step comprises heating the formed body at a temperature higher than 1,250 DEG C to 1,290 DEG C for 2 hours to 10 hours. delete delete The method according to claim 1,
Further comprising the step of performing secondary cogging forging by pressing the outer circumferential surface in a state where the length is arranged in the horizontal direction with the molded body lying down before the mold forging is completed after completion of the reheating step, ≪ / RTI > 5. The method of claim 4,
Further comprising the step of placing the formed body having undergone the secondary cogging forging in an outer mold and pressurizing it using an upper die and an envelope,
Performing mold forging using the mold punch comprises: And forming a punch hole in the upper surface by pressing the upper surface of the molded body filled with the inside of the outer mold using a mold punch. delete Cutting the slab to a predetermined size;
Heating the cut slab;
Molding the molded body by performing at least one blot forging and at least one upsetting on the heated slab;
Performing reheating for the molded body;
And performing mold forging by using a metal mold corresponding to the outer shape of the cylinder cover for the marine engine so that the molded product after the reheating step has the shape of the cylinder cover for the marine engine and using the metal punch corresponding to the inner diameter of the cylinder cover ,
The step of molding the molded body by performing at least one bloom forging and at least one upsetting on the heated slab,
Performing a primary bloom forging to increase the thickness and length while decreasing the width for the heated slab to form a formed body;
Performing primary upsetting such that the length of the primary bloom forging is raised and the length thereof is arranged in the up and down direction, and the formed body is compressed downwardly so that the length is reduced and the width is increased;
The molded body subjected to the first upsetting is laid down so that the length thereof becomes horizontal, and on the contrary, a secondary bloom forging or a first cogging forging is performed in which the angled portions are pressed so as to form a round bar state, Cogging forging is performed before the reheating step after completion of the first upsetting
Wherein the reheating step comprises heating the formed body at a temperature higher than 1,250 DEG C to 1,290 DEG C for 2 hours to 10 hours. delete delete 8. The method of claim 7,
Further comprising the step of performing secondary cogging forging by pressing the outer circumferential surface in a state in which the length is horizontally arranged with the molded body lying down before the mold forging is completed after completion of the reheating step, ≪ / RTI > 11. The method of claim 10,
Further comprising the step of placing the formed body having been subjected to the secondary cogging forging in a ring-shaped metal mold and pressing the upper mold and the upper die using an envelope,
Performing mold forging using the mold punch comprises:
Forming a punch hole which is closed with respect to a part of the molded body by using a downward punch of the mold punch with respect to the molded body filled with the mold;
Reversing the molded body;
Forming a punch hole in an opposite direction to a punch hole formed by using an upward punch in the mold punch so that the punch hole penetrates through the punch hole in the vertical direction.




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