KR102658835B1 - Mold for stainless steel pressure casting - Google Patents

Abstract

One embodiment of the present invention relates to a mold for pressurizing stainless steel casting, which refines the metal structure of the casting and improves surface precision and material strength by pressurizing molten stainless steel.

Description

Mold for stainless steel pressure casting {MOLD FOR STAINLESS STEEL PRESSURE CASTING}

One embodiment of the present invention relates to a mold for pressurizing stainless steel casting, which refines the metal structure of the casting and improves surface precision and material strength by pressurizing molten stainless steel.

Aluminum pressure casting is a widely used technology in the aluminum casting field because it has a faster cooling rate of molten metal compared to general aluminum casting and has effects such as improvement in surface precision and material strength due to refinement of the metal structure.

Meanwhile, in stainless steel casting, general molds are made of steel materials, and since the molten metal is also stainless steel (steel), there were technical limitations in that pressure casting was impossible, such as the molten metal sticking to the surface of the mold or the mold being damaged during pressure casting. .

In the prior art literature on pressure casting, there is a statement such as 'applicable to molten stainless steel', but this only suggests that 'applicable to molten metal of various metal materials', and in actual stainless steel pressure casting, the corresponding prior art It has not been demonstrated that this can be implemented, and according to general technical knowledge, stainless steel pressure casting could not be constructed using conventional technology.

KR 10-1724349 B KR 10-2010-0133487 A

The problem to be solved by an embodiment of the present invention is to overcome the limitations of conventional pressure casting and stainless steel casting as described above, by casting stainless steel through a predetermined mold structure, a predetermined molten metal/mold alloy, and predetermined casting conditions. To provide a stainless steel pressure casting mold that enables pressure casting, thereby refining the metal structure of the casting, and improving surface precision and material strength.

According to one embodiment, a first mold mounted on the bolster of the press device; an insert seated on the top of the first mold; a second mold arranged to slide on top of the first mold; a third mold arranged to slide on top of the first mold and configured to form a predetermined receiving space when in close contact with the second mold; and a fourth mold forming a predetermined cavity by being transferred from the top and inserted into the receiving space while the second mold and the third mold are in close contact with each other, wherein the cavity is: the second mold or the third mold. A mold for stainless steel pressure casting is provided, which is formed to have a predetermined inclination or curvature so that molten metal injected from the top through an injection portion formed in the cavity fills upward from the low point to the high point.

According to one embodiment, a mold in which a predetermined cavity is formed and molten metal is injected; and a press device that applies a predetermined pressure to the mold. In the stainless steel pressure casting device, the mold includes: a first mold mounted on the bolster of the press device; an insert seated on the top of the first mold; a second mold arranged to slide on top of the first mold; a third mold arranged to slide on top of the first mold and configured to form a predetermined receiving space when in close contact with the second mold; and a fourth mold forming a predetermined cavity by being transferred from the top and inserted into the receiving space while the second mold and the third mold are in close contact with each other, wherein the cavity is: the second mold or the third mold. The molten metal injected from the top through the injection portion formed in is formed to have a predetermined inclination or curvature so that the cavity is filled upward from the low point to the high point, and the press device includes: a bolster providing a space in which the mold is seated; a piston provided to apply a predetermined pressure from the top to pressurize the mold; and a hydraulic device that transmits power to the piston. It provides a stainless steel pressure casting device including a.

According to one embodiment, a first mold mounted on the bolster of the press device; an insert seated on the top of the first mold; a second mold arranged to slide on top of the first mold; a third mold arranged to slide on top of the first mold and configured to form a predetermined receiving space when in close contact with the second mold; and a fourth mold forming a predetermined cavity by being transferred from the top and inserted into the receiving space while the second mold and the third mold are in close contact with each other, wherein the cavity is: the second mold or the third mold. Stainless steel pressurization, which manufactures a packing ring for a turbine using a stainless steel pressure casting mold formed to have a predetermined inclination or curvature so that the molten metal injected from the top through the injection portion formed in the cavity is filled upward from the low point to the high point. A casting method comprising: seating the first mold on a bolster of a press device; bringing the second mold and the third mold into close contact with each other by pressing from the left and right sides; Inserting a fourth mold into the receiving space formed between the second mold and the third mold; Pouring molten metal from an upper part of the injection unit through an injection unit formed in the second or third mold and injecting the molten metal into the cavity; and pressurizing the fourth mold after filling the cavity with molten metal.

According to one embodiment, a packing ring for a turbine manufactured according to the stainless steel pressure casting method is provided.

In addition, the cavity includes: a bottom surface formed in the first mold or insert and on which a predetermined first arc-shaped profile is formed with a center point forming the central angle of the arc disposed at the top; a ceiling surface formed in the fourth mold and on which a second arc-shaped profile is formed in which the arc forming the bottom surface is moved in parallel by a predetermined distance; a product portion surrounded by the first arcuate profile and the second arcuate profile; A press unit formed at both ends of the product unit; and a neck portion, which is a point at which the cross-sectional area varies, between the product portion and the press portion.

And, the second mold and the third mold include: an inclined surface that is formed to spread in the left and right directions under pressure from the molten metal when the molten metal is pressurized by the fourth mold, and the fourth mold includes: the inclined surface It may include a wedge formed to correspond to.

In addition, the first to fourth molds include: 0.01 to 0.07% by weight of carbon (C); Manganese (Mn) 0.01 to 1.50% by weight; Silicon (Si) 0.01 to 1.50% by weight; Sulfur (S) 0.01 to 0.040% by weight; Phosphorus (P) 0.01 to 0.040% by weight; Chromium (Cr) 19.0 to 22.0% by weight; 27.5 to 30.5% by weight of nickel (Ni); Molybdenum (Mo) 2.0 to 3.0% by weight; Copper (Cu) 3.0 to 4.0% by weight; and 37.35 to 48.45% by weight of iron (Fe); wherein the molten metal contains: 0.08 to 0.15% by weight of carbon (C); Manganese (Mn) 0.01 to 1.00% by weight; Silicon (Si) 0.01 to 1.00% by weight; Sulfur (S) 0.01 to 0.030% by weight; Phosphorus (P) 0.01 to 0.040% by weight; Chromium (Cr) 11.5 to 13.5% by weight; Nickel (Ni) 0.01 to 0.75% by weight; and 37.35 to 48.45% by weight of iron (Fe). It may be composed of martensitic stainless steel.

In addition, the molten metal has an injection temperature of 1580°C to 1600°C, and an injection molten metal volume of 85% to 90% of the [volume of the riser portion, gate, and cavity formed by the first to fourth molds]. , the injection speed is maintained at the first flow rate during the first injection time, and then the flow rate is controlled to decrease from the first flow rate to 0 during the second injection time, and after the molten metal is filled, the fourth mold is 0.7mm/ It is transported downward at a speed of sec to 1.3 mm/sec for 15 sec to 25 sec and can be controlled to pressurize the molten metal.

According to one embodiment, problems such as residual stress occurring in the product when following the manufacturing process (forging) of a general turbine packing ring and increased manufacturing time due to additional processes can be overcome.

In addition, higher physical properties and recovery rates can be secured compared to existing stainless steel casting methods (gravity casting, centrifugal casting, etc.).

In addition, the metal structure of the casting can be refined, thereby improving the surface precision and material strength of the casting.

In addition, pressure casting of stainless steel, which was difficult to implement according to the prior art, can be achieved.

Figure 1 is a perspective view showing a mold for stainless steel pressure casting according to an embodiment of the present invention.
Figure 2 is a side cross-sectional view showing a mold for stainless steel pressure casting according to an embodiment of the present invention.
Figure 3 is a cross-sectional view showing a portion of a mold for stainless steel pressure casting according to an embodiment of the present invention.
Figure 4 is an exploded perspective view showing a mold for stainless steel pressure casting according to an embodiment of the present invention.
Figure 5 is a diagram showing a stainless steel pressure casting device according to an embodiment of the present invention.
Figure 6 is a diagram showing the molten metal temperature distribution over time in a comparative example and an embodiment of the present invention.
Figure 7 is a diagram showing the distribution of coagulation fraction over time in a comparative example and an embodiment of the present invention.

Hereinafter, various embodiments of this document are described with reference to the attached drawings. However, this is not intended to limit the technology described in this document to specific embodiments, and should be understood to include various modifications, equivalents, and/or alternatives to the embodiments of this document. . In connection with the description of the drawings, similar reference numbers may be used for similar components.

In this document, expressions such as "comprises" or "may include" refer to the presence of the corresponding feature (e.g., a numerical value, function, operation, or component, etc.) and do not exclude the presence of additional features. No.

In this document, expressions such as “one or more of A or/and B” may include all possible combinations of the items listed together. For example, “A or B,” “one or more of A and B” means (1) includes at least one A, (2) includes at least one B, or (3) includes at least one A and at least It can refer to all cases containing all of one B.

Expressions such as “first,” “second,” etc. used in this document may modify various components regardless of order and/or importance, and are only used to distinguish one component from another component. The components are not limited. For example, a first user device and a second user device may represent different user devices regardless of order or importance. For example, a first component may be renamed a second component without departing from the scope of rights described in this document, and similarly, the second component may also be renamed to the first component.

A component (e.g., a first component) is “operatively or communicatively coupled with/to” or “connected” to another component (e.g., a second component). When "connected to" is mentioned, it should be understood that any component may be directly connected to the other component or may be connected through another component (eg, a third component).

Terms used in this document are merely used to describe specific embodiments and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions, unless the context clearly dictates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by a person of ordinary skill in the technical field described in this document. Among the terms used in this document, terms defined in general dictionaries may be interpreted to have the same or similar meaning as the meaning they have in the context of related technology, and unless clearly defined in this document, have an ideal or excessively formal meaning. It is not interpreted as In some cases, even terms defined in this document cannot be interpreted to exclude embodiments of this document.

Of course, various modifications can be made by those skilled in the art without departing from the gist of the present invention as claimed in the claims of the present invention, and these modifications do not reflect the technical idea or implementation of the present invention. It should not be understood in isolation from the perspective.

Terms such as “left and right, front and rear, top and bottom, top and bottom” used in the description of the invention are defined based on the drawings, and the shape and location of each component are not limited by these terms.

In the terms used in this specification, singular expressions should be understood to include plural expressions, unless clearly interpreted differently from the context, and terms such as “including” refer to the described features, numbers, steps, operations, and components. , it means the existence of parts or a combination thereof, but should be understood as not excluding the possibility of the presence or addition of one or more other features, numbers, step operation components, parts, or combinations thereof.

According to one embodiment, a first mold (1) (lower mold) mounted on the bolster (B) of the press device (D); an insert (5) seated on the upper part of the first mold (1); a second mold (2) (first side mold) disposed to slide on top of the first mold (1); A third mold (3) (second side mold) disposed to slide on the top of the first mold (1) and configured to form a predetermined receiving space (S) when in close contact with the second mold (2); And with the second mold (2) and the third mold (3) in close contact, a fourth mold (4) is transferred from the top and inserted into the receiving space (S) to form a predetermined cavity (C) (upper mold) ); and the cavity (C) includes: the molten metal (M) injected from the top through the injection portion (6) formed in the second mold (2) or the third mold (3), ) to provide a mold for stainless steel pressure casting, which is formed to have a predetermined inclination or curvature to fill upward from the low point to the high point.

Hereinafter, the pressure casting process using the mold will be described.

The first mold (1) is fixed to the bolster (B) so as not to shake, and the insert (5) corresponding to the casting to be cast is inserted into the groove formed in the center of the first mold (1).

The second mold (2) and the third mold (3) are seated on the top of the first mold (1), and a pressing device (actuator, etc.) is connected to the second mold (2) and the third mold (3), respectively. By operating it, the second mold (2) and the third mold (3) are brought into close contact with each other.

Thereafter, the molten metal M is injected through the injection portion 6 formed in the second mold 2 or the third mold 3 or by close contact between the second mold 2 and the third mold 3. do. A predetermined injection cup 60 may be fastened to the injection portion 6 to prevent the molten metal M from escaping to the periphery of the mold.

At this time, according to the shape of the cavity (C), the molten metal (M) is filled upward from the low point to the high point of the cavity (C) as shown in the filling direction (D1) shown in FIG. 1.

After completing the injection of the molten metal (M), before the molten metal (M) is completely solidified, the fourth mold (4) is lowered and the molten metal (M) is pressed with the fourth mold (4).

According to one embodiment, a mold in which a predetermined cavity (C) is formed and the molten metal (M) is injected; and a press device (D) that applies a predetermined pressure to the mold. In the stainless steel pressure casting device comprising: a first mold (1) mounted on the bolster (B) of the press device (D); an insert (5) seated on the upper part of the first mold (1); a second mold (2) arranged to slide on top of the first mold (1); a third mold (3) arranged to slide on top of the first mold (1) and configured to form a predetermined receiving space (S) when in close contact with the second mold (2); and a fourth mold (4) that is transferred from the top and inserted into the receiving space (S) to form a predetermined cavity (C) while the second mold (2) and the third mold (3) are in close contact with each other. Includes, the cavity (C): the molten metal (M) injected from the top through the injection portion (6) formed in the second mold (2) or the third mold (3), the low point of the cavity (C) It is formed to have a predetermined inclination or curvature to fill upward from the top to the highest point, and the press device (D) includes: a bolster (B) that provides a space in which the mold is seated; A piston (P) provided to apply a predetermined pressure from the top to pressurize the mold; and a hydraulic device that transmits power to the piston (P). It provides a stainless steel pressure casting device including a.

Here, the mold pressed by the piston (P) may be the second mold (2) to the fourth mold (4), and the second mold (2) is used during the casting process by controlling the hydraulic circuit of the hydraulic device. The pressing force may be released or the pressing force may be applied to some of the to fourth molds 4.

According to one embodiment, a first mold (1) mounted on the bolster (B) of the press device (D); an insert (5) seated on the upper part of the first mold (1); a second mold (2) arranged to slide on top of the first mold (1); a third mold (3) arranged to slide on top of the first mold (1) and configured to form a predetermined receiving space (S) when in close contact with the second mold (2); and a fourth mold (4) that is transferred from the top and inserted into the receiving space (S) to form a predetermined cavity (C) while the second mold (2) and the third mold (3) are in close contact with each other. Includes, the cavity (C): the molten metal (M) injected from the top through the injection portion (6) formed in the second mold (2) or the third mold (3), the low point of the cavity (C) In the stainless steel pressure casting method of manufacturing a packing ring for a turbine using a stainless steel pressure casting mold formed to have a predetermined inclination or curvature so as to be filled upward from to the high point, a packing ring for a turbine is manufactured by attaching a mold to the bolster (B) of the press device (D). Seating the first mold (1); Pressing the second mold (2) and the third mold (3) from the left and right sides, respectively, to bring them into close contact; Inserting the fourth mold (4) into the receiving space (S) formed between the second mold (2) and the third mold (3); Through the injection part 6 formed in the second mold 2 or the third mold 3, the molten metal M is poured from the top of the injection part 6 and the molten metal M is injected into the cavity C. steps; and after filling the cavity (C) with the molten metal (M), pressurizing the fourth mold (4).

After the step of pressurizing the fourth mold 4, after a predetermined time has elapsed and the molten metal M is sufficiently/completely solidified, the fourth mold 4 is raised to complete the process.

The casting made in this way can be manufactured into a packing ring for a turbine through post-processing processes such as surface processing, surface treatment, and cutting.

In addition, the cavity (C) is formed in the first mold (1) or insert (5), and has a bottom surface ( C1); A ceiling surface (C2) formed in the fourth mold (4) and on which a second arc-shaped profile is formed in which the arc forming the bottom surface (C1) is moved in parallel by a predetermined distance; a product portion (C3) surrounded by the first arcuate profile and the second arcuate profile; A press unit (C4) formed at both ends of the product unit (C3); and a neck portion (C5) between the product portion (C3) and the press portion (C4), which is a point at which the cross-sectional area varies.

The detailed configuration of the cavity (C) is shown in FIG. 2.

The molten metal (M) injected from the top to the bottom through the injection part (6)/injection cup (60) is filled upward from the low point of the cavity (C) up to the high point of the molten metal (C4).

In the above description, 'circular profile' may mean a curved surface whose side cross section has a predetermined arc shape.

In addition, the second mold 2 and the third mold 3 are formed to spread in the left and right directions under pressure from the molten metal M when the molten metal M is pressurized by the fourth mold 4. and inclined surfaces 20 and 30, and the fourth mold 4 may include a wedge 40 formed to correspond to the inclined surfaces 20 and 30.

The slopes 20, 30 and wedges 40 are shown in Figure 3.

When the fourth mold 4 receives a load and pressurizes the molten metal M, the molten metal M is pressed in all directions. At this time, if the mold withstands all the load transmitted from the fourth mold (4), problems such as the mold breaking may occur, so a portion of the load is removed by utilizing the inclined surfaces (20, 30) and wedges (40) as described above. It can be induced to disperse in the lateral direction.

At this time, it is desirable to release the pressure/pressure applied to the second mold (2) and third mold (3) so that the second mold (2) and third mold (3) can be opened in the left and right directions. .

Here, releasing the pressure does not mean setting the pressure to 0, but leaving only enough pressure to support the second mold (2) and third mold (3) to prevent unintentional deformation and disperse excessive load. It can mean ordering.

In addition, the first mold (1) to the fourth mold (4) include: 0.01 to 0.07% by weight of carbon (C); Manganese (Mn) 0.01 to 1.50% by weight; Silicon (Si) 0.01 to 1.50% by weight; Sulfur (S) 0.01 to 0.040% by weight; Phosphorus (P) 0.01 to 0.040% by weight; Chromium (Cr) 19.0 to 22.0% by weight; 27.5 to 30.5% by weight of nickel (Ni); Molybdenum (Mo) 2.0 to 3.0% by weight; Copper (Cu) 3.0 to 4.0% by weight; and 37.35 to 48.45% by weight of iron (Fe); wherein the molten metal (M) contains: 0.03 to 0.2% by weight of carbon (C); Manganese (Mn) 0.01 to 1.00% by weight; Silicon (Si) 0.01 to 1.00% by weight; Sulfur (S) 0.01 to 0.030% by weight; Phosphorus (P) 0.01 to 0.040% by weight; Chromium (Cr) 10 to 13.5% by weight; Nickel (Ni) 0.01 to 0.75% by weight; and 37.35 to 48.45% by weight of iron (Fe). It may be composed of martensitic stainless steel.

According to the composition ratio of the mold and molten metal (M) as described above, the carbon and chromium content can be slightly reduced compared to the conventional STS410 material, so that the center of the product is pressurized during pressure casting, and despite pressure casting, the molten metal (M) remains in the mold. Phenomenon such as sticking does not occur, and the casting is taken out normally.

At this time, the insert 5 may be configured in the same way as the first to fourth molds 1 to 4.

Here, preferably, the first mold (1) to the fourth mold (4) contain: 0.035 to 0.07% by weight of carbon (C); Manganese (Mn) 0.75 to 1.50% by weight; Silicon (Si) 0.75 to 1.50% by weight; Sulfur (S) 0.020 to 0.040% by weight; Phosphorus (P) 0.020 to 0.040% by weight; Chromium (Cr) 19.0 to 22.0% by weight; 27.5 to 30.5% by weight of nickel (Ni); Molybdenum (Mo) 2.0 to 3.0% by weight; Copper (Cu) 3.0 to 4.0% by weight; and 46.925 to 48.45% by weight of iron (Fe); wherein the molten metal (M) contains: 0.08 to 0.15% by weight of carbon (C); Manganese (Mn) 0.5 to 1.00% by weight; Silicon (Si) 0.5 to 1.00% by weight; Sulfur (S) 0.015 to 0.030% by weight; Phosphorus (P) 0.02 to 0.040% by weight; Chromium (Cr) 11.5 to 13.5% by weight; Nickel (Ni) 0.0375 to 0.75% by weight; and 37.35 to 48.45% by weight of iron (Fe). It may be composed of martensitic stainless steel.

The weight percent of iron can be calculated by first calculating the weight percent of other components constituting the alloy and then using the remaining weight percent. For example, if the weight % of components other than iron constituting the alloy is 62.65 weight %, iron can be calculated as 37.45 weight %, so that the total weight % can be calculated to be 100%.

In addition, the molten metal (M) has an injection temperature of 1580°C to 1600°C, and the volume of the poured molten metal (M) is [the molten metal (M) formed by the first mold (1) to the fourth mold (4). , gate and cavity (C) volume] is 85% to 90% of the volume, and the injection rate is maintained at the first flow rate during the first injection time, and then the flow rate decreases from the first flow rate to 0 during the second injection time. After the control is performed and the molten metal (M) is filled, the fourth mold (4) is transferred downward at a speed of 0.7 mm/sec to 1.3 mm/sec for 15 sec to 25 sec and pressurizes the molten metal (M). It can be controlled.

Preferably, the injection temperature is 1588°C to 1592°C, and the volume of the injection molten metal (M) is [the pressure portion (C4), gate, and cavity formed by the first mold (1) to fourth mold (4). (C) Volume] is 87% to 89% of the volume, and the injection rate is maintained at the first flow rate during the first injection time, and then the flow rate is controlled to decrease from the first flow rate to 0 during the second injection time, After the molten metal (M) is filled, the fourth mold (4) is transferred downward at a speed of 0.9 mm/sec to 1.1 mm/sec for 15 sec to 25 sec and can be controlled to pressurize the molten metal (M). .

Here, the injection temperature was calculated based on the melting range of the alloy constituting the molten metal (M) of 1482°C to 1532°C.

In the embodiment, the first injection time was 4 seconds, the second injection time was 2 seconds, the molten metal (M) was injected for a total of 6 seconds, and the first flow rate was controlled at 500 cm^3/sec.

6 and 7 show that the injection temperature is 1590°C, and the volume of the injected molten metal (M) is [the pressure portion (C4), gate, and cavity formed by the first mold (1) to fourth mold (4). (C) Volume] is 88% of the volume, the injection rate is maintained at the first flow rate during the first injection time, and then the flow rate is controlled to decrease from the first flow rate to 0 during the second injection time, and the molten metal (M ) is filled, the fourth mold 4 is transferred downward for 15 to 25 sec at a speed of 1 mm/sec and the molten metal (M) is pressed. This is data analyzed based on an example.

Accordingly, the total pressing depth was 10 mm, and the final thickness of the resulting casting was 30.5 mm.

Figures 6 and 7 show a comparative example (fixed upper die) in which the molten metal (M) was observed for 60 seconds with the upper die lowered and fixed, and the molten metal (M) was pressed by lowering the upper die for 6 seconds, and then the molten metal (M) was observed for 60 seconds. This is a diagram comparing and analyzing the example (top type pressurization) in which M) was observed for 60 seconds.

The time to reach final solidification for 'top shape fixation' was confirmed to be 51.89 seconds, and for 'top shape pressurization', the time to reach final solidification was confirmed to be 60.01 seconds. Based on this, the temperature confirmation points in Figure 6 (30, 42, 48, 51.9, 60 seconds) was selected.

General pressure casting has a faster solidification time than general casting, but in the embodiment of the present invention, the final solidification time of 'top mold fixation' was measured to be shorter, which means that the time to reach the final solidification of 'top mold press' is lowered from the upper mold to the product section (C3). ) It is believed that a delay in solidification time occurs because the cross-sectional area of the molten metal (M) is relatively large.

Referring to the comparison of the temperature distribution of the molten metal (M) in FIG. 6, it can be seen that the surface of the runner part reaches 1150°C in 'top mold fixation' after 30 seconds. At 42 seconds, the gate point temperature reached 1200℃ in both 'top mold fixation' and 'top mold pressurization', and at 48 seconds, the temperature difference in the product section (C3) occurred depending on 'top mold fixation' and 'top mold pressurization'. You can check it. Afterwards, at 51.9 seconds, the temperature difference in the press section (C4) between 'top mold fixation' and 'top mold pressurization' is confirmed.

Referring to the comparison of solidification fractions in Figure 7, it can be seen that solidification begins near the gate for both 'top mold fixation' and 'top mold pressurization' at 6 seconds. At 12 seconds, it can be seen that the solidification fraction of the surface part reaches 0.5 for both 'fixing the top mold' and 'pressing the top mold', and the solidification fraction near the center is around 0.25. At 24 seconds, it can be seen that the gate is blocked in 'top type fixation', and in 'top type pressurization', it can be seen that the gate is not blocked. At 30 seconds, it is confirmed that the conduit (neck part (C5)) between the product part (C3) and the presser part (C4) is closed in 'top mold fixation', but in the 'top mold press', the product part (C3) / feeder part (C4) is closed. Sai Tangdo did not close. At 36 seconds, it can be seen that the path to the press section (C4) is closed after the solidification of the product section (C3) is completed in 'top pressurization'.

In the comparative example 'fixing the top mold', the conduit near the presser part (C4) is blocked before the entire product portion (C3) is solidified, and there is a possibility of micro-shrinkage holes occurring in the product portion (C3), but in the example 'top mold pressurization' 'There is almost no possibility of such micro-contraction holes occurring.

This is believed to be due to the pressurization method partially compensating for coagulation shrinkage.

1: 1st mold
2: Second mold
3: Third mold
20, 30: slope
4: 4th mold
40: wedge
5: insert
6: injection part
60: Infusion cup
D1: Filling direction
D2: sliding direction
D3: Pressure direction
S: Accommodating space
M: molten metal
C: Cavity
C1: bottom surface
C2: Ceiling plane
C3: Product Department
C4: Pressure unit
C5: xylem
D: press device
B: Bolster
P: Piston

Claims (5)

A first mold mounted on the bolster of the press device;
an insert seated on the top of the first mold;
a second mold arranged to slide on top of the first mold;
a third mold arranged to slide on top of the first mold and configured to form a predetermined receiving space when in close contact with the second mold; and
With the second mold and the third mold in close contact, a fourth mold is transferred from the top and inserted into the receiving space to form a predetermined cavity,
The cavity is:
The molten metal injected from the top through the injection portion formed in the second mold or the third mold is formed to have a predetermined inclination or curvature so as to fill the cavity upward from the low point to the high point,
The second and third molds are:
When the molten metal is pressurized by the fourth mold, an inclined surface is formed to spread in the left and right directions under pressure from the molten metal;
The fourth mold is:
Including a wedge formed to correspond to the inclined surface,
Mold for stainless steel pressure casting In claim 1,
The cavity is:
a bottom surface formed in the first mold or insert and having a predetermined first arc-shaped profile with a center point forming the central angle of the arc disposed at the top;
a ceiling surface formed in the fourth mold and on which a second arc-shaped profile is formed in which the arc forming the bottom surface is moved in parallel by a predetermined distance;
a product portion surrounded by the first arcuate profile and the second arcuate profile;
A press unit formed at both ends of the product unit; and
Including a neck portion, which is a point where the cross-sectional area varies between the product portion and the press portion,
Mold for stainless steel pressure casting delete In claim 1,
The first to fourth molds are:
Carbon (C) 0.01 to 0.07% by weight;
Manganese (Mn) 0.01 to 1.50% by weight;
Silicon (Si) 0.01 to 1.50% by weight;
Sulfur (S) 0.01 to 0.040% by weight;
Phosphorus (P) 0.01 to 0.040% by weight;
Chromium (Cr) 19.0 to 22.0% by weight;
27.5 to 30.5% by weight of nickel (Ni);
Molybdenum (Mo) 2.0 to 3.0% by weight;
Copper (Cu) 3.0 to 4.0% by weight; and
It is composed of austenitic stainless steel, containing 37.35 to 48.45% by weight of iron (Fe),
The molten metal is:
0.03 to 0.15% by weight of carbon (C);
Manganese (Mn) 0.01 to 1.00% by weight;
Silicon (Si) 0.01 to 1.00% by weight;
Sulfur (S) 0.01 to 0.030% by weight;
Phosphorus (P) 0.01 to 0.040% by weight;
Chromium (Cr) 10 to 13.5% by weight;
Nickel (Ni) 0.01 to 0.75% by weight; and
Consisting of martensitic stainless steel, containing 37.35 to 48.45% by weight of iron (Fe),
Mold for stainless steel pressure casting A first mold mounted on the bolster of the press device;
an insert seated on the top of the first mold;
a second mold arranged to slide on top of the first mold;
a third mold arranged to slide on top of the first mold and configured to form a predetermined receiving space when in close contact with the second mold; and
With the second mold and the third mold in close contact, a fourth mold is transferred from the top and inserted into the receiving space to form a predetermined cavity,
The cavity is:
The molten metal injected from the top through the injection portion formed in the second mold or the third mold is formed to have a predetermined inclination or curvature so as to fill the cavity upward from the low point to the high point,
The molten metal is:
The injection temperature is 1580°C to 1600°C,
The volume of the molten metal injected is 85% to 90% of the volume of the filler portion, gate, and cavity formed by the first to fourth molds,
The injection speed is maintained at the first flow rate during the first injection time, and then is controlled so that the flow rate decreases from the first flow rate to 0 during the second injection time,
After the molten metal is filled, the fourth mold is transported downward at a speed of 0.7 mm/sec to 1.3 mm/sec for 15 sec to 25 sec and pressurizes the molten metal,
Mold for stainless steel pressure casting