WO2016080139A1 - 消失模型鋳造方法 - Google Patents
消失模型鋳造方法 Download PDFInfo
- Publication number
- WO2016080139A1 WO2016080139A1 PCT/JP2015/079751 JP2015079751W WO2016080139A1 WO 2016080139 A1 WO2016080139 A1 WO 2016080139A1 JP 2015079751 W JP2015079751 W JP 2015079751W WO 2016080139 A1 WO2016080139 A1 WO 2016080139A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- coating agent
- hole
- casting
- molten metal
- model
- Prior art date
Links
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
- B22C7/02—Lost patterns
- B22C7/023—Patterns made from expanded plastic materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C3/00—Selection of compositions for coating the surfaces of moulds, cores, or patterns
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C7/00—Patterns; Manufacture thereof so far as not provided for in other classes
- B22C7/02—Lost patterns
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/04—Use of lost patterns
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22C—FOUNDRY MOULDING
- B22C9/00—Moulds or cores; Moulding processes
- B22C9/02—Sand moulds or like moulds for shaped castings
- B22C9/04—Use of lost patterns
- B22C9/046—Use of patterns which are eliminated by the liquid metal in the mould
Definitions
- the present invention relates to a vanishing model casting method for casting a casting having a hole.
- the disappearance model casting method is considered to be the most suitable method for forming a hole in a casting by casting (referred to as “casting”).
- the disappearance model casting method is a method in which a mold formed by applying a coating agent on the surface of the foam model is buried in the casting sand, and then a molten metal is poured into the mold to disappear the foam model. It is a method of casting a casting by replacing it.
- Patent Document 1 discloses a disappearance model casting method in which the casting time during casting is set according to the modulus of the model (model volume / model surface area).
- the casting agent applied to the surface of the hole portion of the foam model and the casting sand filled in the hole portion from the periphery during casting in the course of solidification.
- the heat load is large, and various external forces act from the molten metal.
- the hole part of a foaming model is a part in which a hole is formed by casting. Therefore, as shown in FIG. 18, which is a conceptual diagram, the coating agent 24 is damaged at the hole end portion 23 a and the central portion 23 b of the hole portion 23, and the molten metal 26 is poured into the casting sand 25 filled in the hole portion 23. May ooze out.
- the coating agent 24 is damaged, thereby causing “burning” in which the molten metal 26 and the cast sand 25 are fused, and the finished state is good. It becomes difficult to form a narrow hole.
- a narrow hole having a diameter of 18 mm or less and a length of 50 mm or more is not punched, and a thin hole is made by machining later on the cast casting.
- a narrow hole having a diameter of 18 mm or less and a length of 50 mm or more is cast out. Stable manufacturing is difficult.
- An object of the present invention is to provide a disappearing model casting method capable of casting a fine hole having a diameter of 18 mm or less and having a good finished state.
- the thickness of the coating agent applied to the foamed model is t (mm)
- the hole When the diameter of the hole portion of the foamed model that is a portion formed is D (mm) and the bending strength at room temperature of the dried coating agent is ⁇ c (MPa), the peripheral portion of the hole portion
- the coating agent satisfying the following formula is used.
- the solidification end time te (second) at which the solidification of the molten metal is completed in the peripheral portion of the hole is applied.
- a coating agent satisfying the above formula is used within the time t0 when the thermal decomposition of the mold is completed.
- the bending strength of the coating agent that was heated to the resin decomposition until it was decomposed and then returned to room temperature was about the normal bending strength of the resin binder obtained by drying the coating agent as it was.
- the bending strength of the coating agent that is not a complete sintered body is the coating mold that is a completely sintered body. It is presumed to be higher than the bending strength of the agent.
- the strength of the coating agent as the resin binder is ⁇ c at room temperature, and decreases with the progress of thermal decomposition of the resin, and becomes 0 when the decomposition rate is 100%.
- the solidification end time te (second) at which the solidification of the molten metal ends in the peripheral part of the hole is within the time t0 (second) when the thermal decomposition of the coating agent is completed, the resin binder is bonded to the coating agent. Strength remains.
- the above formula is obtained. Therefore, by using a mold agent satisfying the above formula, the mold agent can be prevented from being damaged even when a casting having a narrow hole having a diameter of 18 mm or less is cast. Thereby, since seizure does not occur at the time of casting, it is possible to cast a fine hole having a diameter of 18 mm or less and having a good finished state.
- FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. It is an enlarged view of the principal part B of FIG. It is a side view of a casting_mold
- FIG. 6 is a cross-sectional view taken along the line CC of FIG. It is an enlarged view of the principal part D of FIG. It is a figure which shows the relationship between the bending strength of the mold agent which returned to normal temperature after heating until resin decomposition, and the diameter which can be cast.
- a mold formed by applying a coating agent on the surface of a foam model is buried in casting sand (dry sand), and then a molten metal is poured into the mold to foam.
- This is a method for casting a casting having a hole having a diameter of 18 mm or less and a length of 1 (mm) by eliminating the model and replacing it with molten metal.
- This vanishing model casting method is considered to be the most suitable method for casting, for example, a casting having a narrow hole having a diameter of 18 mm or less and a length of 100 mm or more by “casting”.
- the vanishing model casting method includes a melting step of melting metal (cast iron) to form a molten metal, a molding step of forming a foamed model, and a coating step of applying a coating agent on the surface of the foamed model to form a mold.
- the disappearance model casting method melts the foamed model by pouring molten metal (molten metal) into the casting mold and filling the casting sand into the casting mold by filling the casting mold in the casting sand.
- a casting step for replacing the molten metal has a cooling step of cooling the molten metal poured into the mold to form a casting, and a separation step of separating the casting from the casting sand.
- gray cast iron JIS-FC250
- spheroidal graphite cast iron JIS-FCD450
- foam model a foam resin such as polystyrene foam
- coating agent a silica-based aggregate coating agent or the like can be used.
- silica-based aggregate coating agent or the like can be used.
- silica-based aggregate coating agent or the like can be used.
- silica-based aggregate coating agent or the like can be used.
- silica-based aggregate coating agent or the like can be used as the sand.
- sica sand containing SiO 2 as a main component
- the thickness of the coating agent is preferably 3 mm or less. When the thickness of the coating agent is 3 mm or more, it is necessary to repeat coating and drying of the coating agent three times or more, which is troublesome and the thickness tends to be non-uniform.
- the solidification end time te (second) is within the time t0 (second)
- the coating agent satisfying the formula (1) is used.
- the solidification end time te (seconds) is the time at which the solidification of the molten metal ends in the peripheral part of the hole of the foam model.
- the time t0 (second) is the time when the thermal decomposition of the coating agent is completed.
- the hole part of a foaming model is a part in which a hole is formed by casting.
- ⁇ c ⁇ ⁇ t0 / (t0 ⁇ te) ⁇ ⁇ (1.5 ⁇ 10 ⁇ 4 ⁇ l 2 / t 2 + 160 / D 2 )
- l is the length (mm) of the hole formed in the casting
- t is the thickness (mm) of the coating agent applied to the foam model
- D is the diameter (mm) of the hole of the foam model
- ⁇ c is dried.
- FIG. 1A is a top view of the mold
- FIG. 1B is a side view of the mold.
- a mold having a hole 3 having a diameter D (mm) and a length 1 (mm) penetrating from the upper surface to the lower surface in the center of a rectangular foam model 2 Considering the case of casting a casting having a narrow hole having a diameter of 18 mm or less and a length of 1 (mm) using No. 1.
- the hole part 3 is provided so that an angle may be formed between the hole end part 3a and the surface of the foam model 2. That is, the hole end portion 3a is not processed with a taper or the like.
- the diameter D of the hole 3 is the length between the surfaces of the hole 3 across the center line of the hole 3, and is the length between the surfaces of the coating agent applied to the surface of the hole 3. Absent.
- the diameter of the narrow hole is preferably 10 mm or more.
- the diameter of the narrow hole is more preferably 18 mm or less. This is because when a coating agent having a thickness of 3 mm is applied to the surface of a fine hole having a diameter of 10 mm, the inner diameter of the space inside the fine hole becomes 4 mm, and it becomes difficult to throw casting sand into the fine hole.
- a load acting on the coating agent applied to the surface of the hole 3 of the foam model 2 is predicted.
- the following external force acts on the coating agent applied to the hole end 3 a of the hole 3.
- Melt static pressure ( ⁇ p) (2) Dynamic pressure due to molten metal flow ( ⁇ m) (3) Thermal contraction / expansion difference ( ⁇ thout) during solidification of coating agent and molten metal (4) Thermal contraction / expansion difference ( ⁇ thin) between casting sand in hole 3 and coating agent (5) Pressure of gas generated by combustion of foam model (Pgout) ( ⁇ gout) (6) Internal pressure (Pgin) ( ⁇ gin) generated when the gas generated by the combustion of the foam model is accumulated inside the hole 3
- FIG. 2 which is a side view of the mold 1
- the casting sand 5 filled around the foamed model 2 receives the static pressure of the molten metal 6.
- FIG. 3 which is a cross-sectional view taken along the line AA of FIG. 2, the coating agent 4 applied to the surface of the hole 3 receives a compressive force in the circumferential direction.
- FIG. 4 is an enlarged view of the main part B of FIG.
- the static pressure of the molten metal 6 and the reaction force from the casting sand 5 are balanced. Therefore, the axial load of the hole 3 can be ignored.
- the diameter of the hole 3 is D (mm)
- the acceleration of gravity is g
- the density of the molten metal 6 is ⁇ m (kg / mm 3 ).
- the external force w (N / mm) to the hole 3 (semicircle) due to the static pressure of the molten metal 6 is the average head difference (the difference in vertical height between the molten metal gate and the hole 3) h (mm).
- the molten metal gate is a portion where the molten metal is poured into the casting sand surrounding the foamed model above the hole.
- FIG. 5 is a side view of the mold 1
- the foam model 2 disappears and is replaced with the molten metal 6
- the casting sand 5 filled around the foam model 2 is gas generated by the combustion of the foam model 2. Under pressure.
- FIG. 6 which is a CC cross-sectional view of FIG. 5
- the coating agent 4 applied to the surface of the hole 3 receives a compressive force in the circumferential direction.
- FIG. 7 which is an enlarged view of the main part D of FIG. 5
- a tensile force of the following expression (5) is given in the axial direction of the hole 3.
- ⁇ b> ⁇ p + ⁇ gout ( ⁇ / 8) ⁇ mghl 2 / t 2 + kPgout / D 2 + ⁇ (8)
- k is a proportional constant
- ⁇ ⁇ m + ⁇ thout + ⁇ thin + ⁇ gin ⁇ 0.
- Equation (8) is the most severe condition that is established when there is no reaction force of the sand. Therefore, if each term is replaced with a coefficient in consideration of the reaction force of casting sand, the function is a function of the diameter D and length l of the hole 3 and the thickness t of the coating agent as shown in equation (9). Can do.
- Equation (9) can be expressed by Equation (10).
- the thickness of the coating agent applied to the foamed model is 1 mm or more, thereby providing a narrow hole having a diameter of 18 mm or less and a length of 100 mm or more. Even if a casting is cast, the coating agent can be prevented from being damaged.
- said Formula (10) is calculated
- the bending strength ⁇ n of the coating agent heated until it decomposes into a resin to be sintered and then returned to room temperature is the resistance to normal temperature as a resin binder obtained by drying the coating agent as it is. It is reduced to about 1/7 or less of the bending strength ⁇ c. From this fact, the bending strength of the coating agent in which the resin decomposition is not completely completed, that is, not completely sintered, is the bending strength ⁇ n of the coating agent completely sintered. Is estimated to be higher.
- Fig. 9 shows the relationship between the temperature of the coating agent during casting and the strength of the coating agent.
- the bending strength of the coating agent is ⁇ c
- the bonding strength of the aggregate by the resin determines the strength of the coating agent.
- the resin decomposition of the coating agent is started by heating, the strength of the coating agent decreases as the thermal decomposition of the resin proceeds.
- the bending strength of the coating agent becomes the bending strength ⁇ n of the sintered body which is returned to room temperature (RT).
- FIG. 10 shows the relationship between the temperature of the coating agent during casting and the strength of the coating agent.
- the resin decomposition of the coating agent is completely completed when the solidification of the molten metal is completed in the peripheral part of the hole. It is expected that the sintered body is not a complete sintered body. If the coating agent is not a completely sintered body, the strength as a resin binder remains in the coating agent, and the strength is the bending strength ⁇ n of the coating agent in the sintered body. Is estimated to be higher.
- the strength as a resin binder remains in the coating agent.
- the resin is caking into the coating agent.
- the strength as a body remains.
- the bending strength of the coating agent which is not a complete sintered body is higher than the bending strength ⁇ n of the coating agent which is a sintered body. For this reason, it can be said that when the strength as a resin binder remains in the coating agent, the coating agent is less likely to be damaged and “burn-in” is less likely to occur.
- reaction rate formula of the thermal decomposition of the resin used for the coating agent can be expressed by the following formula (11).
- kt f ( ⁇ ) (11)
- k is a reaction rate constant
- t is a reaction time (second)
- ⁇ is a decomposition rate
- f ( ⁇ ) is a function of the decomposition rate ⁇ .
- the hot strength ⁇ b of the coating agent can be expressed by the following formula (12).
- g ( ⁇ ) is a function that determines the hot strength ⁇ b at the decomposition rate ⁇ .
- the time t0 at which the thermal decomposition of the coating agent is completed can be approximated to 1600 seconds.
- the solidification end time te (second) at which the solidification of the molten metal ends in the peripheral portion of the hole is within the time t0 (second) at which the thermal decomposition of the coating agent is completed, Since it can be said that the strength remains, Equation (13) is obtained.
- Equation (14) When ⁇ and ⁇ in Equation (9) are obtained from test results (details will be described later) in a mold having a short side of a cross section perpendicular to the axial direction of the hole of 100 mm, the following Equation (14) is obtained.
- Equation (12) is a linear equation
- equation (16) Substituting equation (16) into equation (15) yields equation (17).
- equation (17) By using a coating agent that satisfies this formula (17), it is possible to prevent “burn-in” from occurring.
- the shape of the mold is not limited to a rectangular parallelepiped, and may be a prismatic shape such as a triangular prism or a pentagonal prism, or a cylindrical shape.
- the solidification end time te at which the solidification of the molten metal is completed in the peripheral portion of the hole is the short side T ( (See FIG. 1A).
- equation (20) ⁇ c ⁇ t0 / (t0 + 1.03 ⁇ 10 ⁇ 3 T 2 ⁇ 16.5T) ⁇ (1.5 ⁇ 10 ⁇ 4 ⁇ l 2 / t 2 + 160 / D 2 ) (20)
- the length of the narrow hole formed by casting is set to 100 mm.
- the diameters of the agent, the casting sand, and the hole 3 were varied, and the feasibility of casting was evaluated.
- the size of the three blocks is 100 (mm) ⁇ 200 (mm) ⁇ 100 (mm), 50 (mm) ⁇ 200 (mm) ⁇ 100 (mm) in the order of short side T, long side, and height, respectively. 25 (mm) ⁇ 200 (mm) ⁇ 100 (mm).
- FIG. 11A shows a top view of a block having a short side T of 100 mm
- FIG. 11A shows a top view of a block having a short side T of 100 mm
- FIG. 11B shows a side view thereof.
- a top view of a block having a short side T of 50 mm is shown in FIG. 12A and a side view thereof is shown in FIG. 12B.
- FIG. 13A shows a top view
- FIG. 13B shows a side view of a block having a short side T of 25 mm.
- Table 1 shows the types of coating agents.
- Table 2 shows the results of whether or not casting is possible. This evaluation is performed by the same casting method using gray cast iron (JIS-FC250) having the same components.
- the bending strength ⁇ n of the coating agent heated to the resin decomposition until it was made into a sintered body and then returned to room temperature was the normal temperature as the resin binder obtained by drying the coating agent as it was. It turns out that it falls to about 1/7 or less of the bending strength ⁇ c. From this fact, the bending strength of the coating agent in which the resin decomposition is not completely completed, that is, not completely sintered, is the bending strength ⁇ n of the coating agent completely sintered. Is estimated to be higher.
- Casting software JSCAST (Qualica) was used to determine the solidification time around the hole with a diameter of 14 mm when the short side T of the block was varied.
- a perspective view of the block is shown in FIG.
- the long side and height of the block were 100 mm and 200 mm, respectively, and the short side T of the block was different from 100 mm, 50 mm, and 25 mm.
- the block was provided with holes in the center in the height direction, the upper stage (position 50 mm from the upper end face), and the lower stage (position 50 mm from the lower end face).
- the molten metal was assumed to be gray cast iron (JIS-FC250) and its physical property values were given.
- FIG. 15A shows a cooling curve in the periphery of the hole in a block having a short side T of 100 mm. Moreover, the cooling curve in the peripheral part of a hole part in the block whose short side T is 50 mm is shown to FIG. 15B. Moreover, the cooling curve in the peripheral part of a hole part in the block whose short side T is 25 mm is shown to FIG. 15C.
- “hole center”, “casting surface layer”, and “casting second layer”, which are measurement locations, are the locations shown in FIG. Due to the latent heat of solidification when the melt solidifies, the temperature of the melt gradually decreases until the melt is completely solidified. Then, after the molten metal is completely solidified, the temperature of the molten metal quickly decreases. Therefore, the inflection point in the cooling curve may be considered as the solidification completion time.
- the block is also affected by heat removal from the height direction. Therefore, the solidification rate of the holes provided in the upper stage of the block (position 50 mm from the upper end face) and the lower stage of the block (position 50 mm from the lower end face) is higher than that of the hole provided in the center of the block. fast.
- Table 3 shows the results of solidification time and castability of the upper and lower holes provided in the block having a short side T of 100 mm in FIG.
- the coating agent used for the block having a short side T of 100 mm does not satisfy the formula (10).
- the experimental results shown in Table 3 show that the solidification time around the upper and lower hole portions of the block is less than 1600 seconds, and it is possible to cast a fine hole with a good finished state.
- the solidification time around the middle hole of the block is longer than 1600 seconds, and it can be seen that a fine hole with a good finished state cannot be cast. Therefore, it can be seen that “casting” is possible at the upper and lower stages where the solidification rate is high, even if the condition of the expression (10) is not satisfied.
- the relationship between the short side T and the solidification end time te is shown in FIG. From FIG. 16, it can be seen that the condition of the formula (10) needs to be satisfied when the solidification end time te is 1600 seconds or more. From this, the solidification end time te needs to be within 1600 seconds, and thus it can be seen that the time t0 at which the thermal decomposition of the coating agent ends can be approximated to 1600 seconds.
- the central hole of the block having a short side T of 100 mm is the limit (t0 ⁇ 1600 (seconds)) of the expression (10). Therefore, two conditions, ie, the casting limit of the coating agent A (diameter 8 mm where the casting is impossible) and the diameter 14 mm of the coating agent B, which are representative examples of the punching test results shown in Table 2, are respectively set. Substituting into equation (9) to solve the simultaneous equations and find ⁇ and ⁇ , equation (14) is obtained. ⁇ b> 1.5 ⁇ 10 ⁇ 4 ⁇ l 2 / t 2 + 160 / D 2 Formula (14)
- the coating agent satisfying the formula (17) or the formula (18) it is possible to prevent the coating agent from being damaged even when casting a casting having a narrow hole having a diameter of 18 mm or less. I understand.
- the coating agent satisfying the formula (20) or the formula (21) it is possible to prevent the coating agent from being damaged even if a casting having a narrow hole having a diameter of 18 mm or less is cast. I understand.
- the bending strength of the coating agent in which the resin decomposition is not completely completed, that is, not a complete sintered body is more than the bending strength of the coating agent that is a completely sintered body.
- the strength of the coating agent as the resin binder is ⁇ c at room temperature, and decreases with the progress of thermal decomposition of the resin, and becomes 0 when the decomposition rate is 100%.
- the solidification end time te (second) at which the solidification of the molten metal ends in the peripheral part of the hole is within the time t0 (second) when the thermal decomposition of the coating agent is completed, the resin binder is bonded to the coating agent. Strength remains.
- the above formula (17) is obtained. Therefore, by using a coating agent satisfying the above formula (17), it is possible to prevent the coating agent from being damaged even if a casting having a narrow hole having a diameter of 18 mm or less is cast. Thereby, since seizure does not occur at the time of casting, it is possible to cast a fine hole having a diameter of 18 mm or less and having a good finished state.
- the coating agent is used when the solidification completion time te (seconds) at which the solidification of the molten metal ends at the periphery of the hole is within 1600 seconds.
- the strength as a resin caking body remains. Therefore, at this time, it is possible to prevent the coating agent from being damaged by using the coating agent satisfying the above formula (18).
- the solidification end time te at which the solidification of the molten metal is completed in the peripheral portion of the hole is expressed by the above formula (19) as a function of the short side T of the cross section orthogonal to the axial direction of the hole in the mold. Therefore, when this relationship is satisfied, the coating agent can be prevented from being damaged by using the coating agent satisfying the above formulas (20) and (21).
Abstract
Description
σc≧{t0/(t0-te)}×(1.5×10-4 ×l2/t2+160/D2)
本発明の実施形態による消失模型鋳造方法は、発泡模型の表面に塗型剤を塗布してなる鋳型を鋳砂(乾燥砂)の中に埋めた後に、鋳型内に金属の溶湯を注ぎ込み、発泡模型を消失させて溶湯と置換することで、直径が18mm以下で長さがl(mm)の穴を備えた鋳物を鋳造する方法である。この消失模型鋳造方法は、「鋳抜き」によって、例えば、直径が18mm以下で長さが100mm以上の細穴を備えた鋳物を鋳造するのに最も適した方法であると考えられる。
ここで、lは鋳物に形成する穴の長さ(mm)、tは発泡模型に塗布する塗型剤の厚み(mm)、Dは発泡模型の穴部の直径(mm)、σcは乾燥させた塗型剤の常温の抗折強度(曲げ強さ)(MPa)である。
(1)溶湯の静圧(σp)
(2)溶湯の流れによる動圧(σm)
(3)塗型剤と溶湯との凝固時の熱収縮・膨張差(σthout)
(4)穴部3内の鋳砂と塗型剤との熱収縮・膨張差(σthin)
(5)発泡模型の燃焼で発生したガスの圧力(Pgout)(σgout)
(6)発泡模型の燃焼で発生したガスが穴部3の内部に溜まって生じる内圧(Pgin)(σgin)
鋳型1の側面図である図2に示すように、発泡模型2を消失させて溶湯6と置換すると、発泡模型2の周囲に充填された鋳砂5は、溶湯6の静圧を受ける。図2のA-A断面図である図3に示すように、穴部3の表面に塗布された塗型剤4は、周方向に圧縮力を受ける。
=ρmghD/2×∫sin2θdθ
=ρmghD/2〔θ/2-sin2θ/4〕
=(π/4)ρmghD ・・・式(3)
ここで、Mは穴部3の両端に作用するモーメント、Iは半円筒の断面2次モーメントである。
M=(π/48)ρmghDl2
I=Dt3/12
溶湯の流れによる動圧は、溶湯の流れが静かであることを前提とすると、無視することができる。
線膨張率は、鋳砂より鋳鉄の方が大きい。よって、塗型剤と溶湯との凝固時の熱収縮・膨張差は、塗型剤の軸方向に圧縮力を与える。この圧縮力は、塗型剤が形成する円管が座屈により破壊される原因になりうるが、無視できるほど小さいと考えられる。また、塗型剤の周方向の応力も無視することができる。
穴部3内の鋳砂や塗型剤は、溶湯よりも温度変化が小さい。よって、穴部3内の鋳砂と塗型剤との熱収縮・膨張差による影響は、塗型剤と溶湯との凝固時の熱収縮・膨張差よりも小さく、無視することができる。
鋳型1の側面図である図5に示すように、発泡模型2を消失させて溶湯6と置換すると、発泡模型2の周囲に充填された鋳砂5は、発泡模型2の燃焼で発生したガスの圧力を受ける。
発泡模型2の燃焼で発生したガスが穴部3の内部に溜まって生じる内圧は、塗型剤に式(6)の周方向の応力、および、式(7)の軸方向の応力を生じさせる。
σginz≒D×Pgin/(2t) ・・・式(7)
ここで、kは比例定数、γ=σm+σthout+σthin+σgin≒0である。
ここで、上記の式(10)は、穴部の軸方向に直交する断面の短辺が100mmの鋳型を用いて求められている。そして、穴部の周辺部において溶湯の凝固が完了するまでに、穴部の塗型剤は焼結体になっている。よって、「焼き付き」を生じさせないためには、塗型剤の焼結体としての熱間強度が、浮力などの外力の合計を上回る必要がある。
kt=f(α) ・・・式(11)
ここで、kは反応速度定数、tは反応時間(秒)、αは分解率、f(α)は分解率αの関数である。
σb=g(α)=g(f-1 (kte))=h(te) ・・・式(12)
ここで、g(α)は分解率αにおける熱間強度σbを決める関数である。
te≦t0≒1600(秒) ・・・式(13)
σb>1.5×10-4 ×l2/t2+160/D2 ・・・式(14)
kσc≧1.5×10-4 ×l2/t2+160/D2 ・・・式(15)
ここで、kは樹脂分解状況で変わる係数である。
k=1-te/t0 ・・・式(16)
σc≧{t0/(t0-te)}×(1.5×10-4 ×l2/t2+160/D2) ・・・式(17)
σc≧{1600/(1600-te)}×(1.5×10-4 ×l2/t2+160/D2) ・・・式(18)
te=-1.03×10-3 T2+16.5T ・・・式(19)
σc≧t0/(t0+1.03×10-3 T2-16.5T)×(1.5×10-4 ×l2/t2+160/D2) ・・・式(20)
σc≧1600/(1600+1.03×10-3 T2-16.5T)×(1.5×10-4×l2/t2+160/D2) ・・・式(21)
次に、穴部の軸方向に直交する断面の短辺Tの長さが異なる3体のブロック(鋳型)に対し、鋳抜きで形成する細穴の長さを100mmとした場合について、塗型剤、鋳砂、および、穴部3の直径をそれぞれ異ならせて、鋳抜きの可否を評価した。3体のブロックのサイズは、短辺T、長辺、高さの順にそれぞれ、100(mm)×200(mm)×100(mm)、50(mm)×200(mm)×100(mm)、25(mm)×200(mm)×100(mm)である。短辺Tが100mmのブロックの上面図を図11Aに、側面図を図11Bにそれぞれ示す。また、短辺Tが50mmのブロックの上面図を図12Aに、側面図を図12Bにそれぞれ示す。また、短辺Tが25mmのブロックの上面図を図13Aに、側面図を図13Bにそれぞれ示す。また、塗型剤の種類を表1に示す。また、鋳抜き可否の結果を表2に示す。なお、この評価は、同じ成分のねずみ鋳鉄(JIS-FC250)を用いて、同じ鋳造方法で行っている。
σb>1.5×10-4 ×l2/t2+160/D2 ・・・式(14)
σc≧{1600/(1600-te)}×(1.5×10-4 ×l2/t2+160/D2) ・・・式(18)
te=-1.03×10-3 T2+16.5T ・・・式(19)
σc≧t0/(t0+1.03×10-3 T2-16.5T)×(1.5×10-4 ×l2/t2+160/D2) ・・・式(20)
σc≧1600/(1600+1.03×10-3 T2-16.5T)×(1.5×10-4×l2/t2+160/D2) ・・・式(21)
次に、ねずみ鋳鉄(JIS-FC250)を溶湯として用いて、50(mm)×100(mm)×200(mm)の直方体の発泡模型に、上面から下面にかけて貫通する、長さ100mmで直径14mmの穴部を配置した鋳型を用いて、細穴を備えた鋳物を鋳造した。
以上に述べたように、本実施形態に係る消失模型鋳造方法によると、直径が18mm以下で長さがl(mm)の穴を備えた鋳物を鋳造するに際して、穴部の周辺部において溶湯の凝固が終了する凝固終了時間te(秒)が、塗型剤の熱分解が終了する時間t0以内のときに、上記の式(17)を満たす塗型剤を用いる。ここで、塗型剤の高温強度を直接測定することは困難である。しかし、塗型剤を樹脂分解するまで加熱して焼結体にした後に常温に戻したものの抗折強度が、塗型剤をそのまま乾燥させた樹脂粘結体としての常温の抗折強度の約1/7以下に低下する。このことから、樹脂分解が完全に終了していない、即ち、完全な焼結体になっていない塗型剤の抗折強度は、完全に焼結体になった塗型剤の抗折強度よりも高いものと推定される。樹脂粘結体としての塗型剤の強度は、常温においてσcであり、樹脂の熱分解の進行にともなって低下していき、分解率が100%のときに0となる。しかし、穴部の周辺部において溶湯の凝固が終了する凝固終了時間te(秒)が、塗型剤の熱分解が終了する時間t0(秒)以内であれば、塗型剤に樹脂粘結体としての強度が残存する。そこで、塗型剤に残存している樹脂粘結体としての強度を考慮すると、上記の式(17)が得られる。よって、上記の式(17)を満たす塗型剤を用いることで、直径が18mm以下の細穴を備えた鋳物を鋳造しても、塗型剤が損傷しないようにすることができる。これにより、鋳造時に焼き付きが生じないので、直径が18mm以下であって、仕上がり状態が良好な細穴を鋳抜くことができる。
2 発泡模型
3 穴部
3a 穴端部
4 塗型剤
5 鋳砂
6 溶湯
23 穴部
23a 穴端部
23b 中央部
24 塗型剤
25 鋳砂
26 溶湯
Claims (3)
- 発泡模型の表面に塗型剤を塗布してなる鋳型を鋳砂の中に埋めた後に、前記鋳型内に金属の溶湯を注ぎ込み、前記発泡模型を消失させて前記溶湯と置換することで、直径が18mm以下で長さがl(mm)の穴を備えた鋳物を鋳造する消失模型鋳造方法において、
前記発泡模型に塗布する前記塗型剤の厚みをt(mm)、前記穴が形成される部分である前記発泡模型の穴部の直径をD(mm)、乾燥させた前記塗型剤の常温の抗折強度をσc(MPa)とすると、前記穴部の周辺部において前記溶湯の凝固が終了する凝固終了時間te(秒)が、前記塗型剤の熱分解が終了する時間t0(秒)以内のときに、以下の式を満たす前記塗型剤を用いることを特徴とする消失模型鋳造方法。
σc≧{t0/(t0-te)}×(1.5×10-4 ×l2/t2+160/D2) - 前記塗型剤の熱分解が終了する時間t0が1600秒であることを特徴とする請求項1に記載の消失模型鋳造方法。
- 前記鋳型の形状は直方体であり、
前記鋳型における前記穴部の軸方向に直交する断面の短辺をTとすると、以下の式を満たすことを特徴とする請求項1又は2に記載の消失模型鋳造方法。
te=-1.03×10-3 T2+16.5T
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US15/520,009 US10099274B2 (en) | 2014-11-19 | 2015-10-21 | Evaporative pattern casting method |
CN201580062100.XA CN107107166B (zh) | 2014-11-19 | 2015-10-21 | 消失模铸造法 |
DE112015005231.3T DE112015005231B4 (de) | 2014-11-19 | 2015-10-21 | Verdampfungsmustergiessverfahren |
KR1020177012566A KR101950125B1 (ko) | 2014-11-19 | 2015-10-21 | 소실 모형 주조 방법 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2014234455A JP6231465B2 (ja) | 2014-11-19 | 2014-11-19 | 消失模型鋳造方法 |
JP2014-234455 | 2014-11-19 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2016080139A1 true WO2016080139A1 (ja) | 2016-05-26 |
Family
ID=56013696
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2015/079751 WO2016080139A1 (ja) | 2014-11-19 | 2015-10-21 | 消失模型鋳造方法 |
Country Status (7)
Country | Link |
---|---|
US (1) | US10099274B2 (ja) |
JP (1) | JP6231465B2 (ja) |
KR (1) | KR101950125B1 (ja) |
CN (1) | CN107107166B (ja) |
DE (1) | DE112015005231B4 (ja) |
TW (1) | TWI592229B (ja) |
WO (1) | WO2016080139A1 (ja) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN106077474A (zh) * | 2016-07-26 | 2016-11-09 | 柳州金特新型耐磨材料股份有限公司 | 一种后桥壳体热处理工艺 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63183744A (ja) * | 1987-01-26 | 1988-07-29 | Nabeya:Kk | 多孔性鋳造品の製造方法 |
JPH01266941A (ja) * | 1988-04-20 | 1989-10-24 | Mitsubishi Heavy Ind Ltd | 消失模型用塗型剤 |
JP2003290873A (ja) * | 2002-04-08 | 2003-10-14 | Kao Corp | 消失模型鋳造法 |
Family Cites Families (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH01154847A (ja) * | 1987-12-09 | 1989-06-16 | Morikawa Sangyo Kk | 消失性模型を用いる鋳物の鋳造方法 |
US5203398A (en) * | 1992-01-31 | 1993-04-20 | The Board Of Trustees Of Western Michigan University | Low temperature process for evaporative pattern casting |
US5848351A (en) | 1995-04-03 | 1998-12-08 | Mitsubishi Materials Corporation | Porous metallic material having high specific surface area, method of producing the same, porous metallic plate material and electrode for alkaline secondary battery |
TW381981B (en) | 1995-09-27 | 2000-02-11 | Mitsubishi Materials Corp | Method and apparatus for making sintered porous metal plate |
JP2006175494A (ja) * | 2004-12-24 | 2006-07-06 | Mie Katan Kogyo Kk | ダクタイル鋳鉄のフェライト地鋳物の製造方法 |
CN101503774B (zh) * | 2009-03-09 | 2010-12-08 | 西北工业大学 | 铸造镁合金材料的制备方法 |
JP5491144B2 (ja) | 2009-11-26 | 2014-05-14 | 本田技研工業株式会社 | 消失模型鋳造法 |
CN102686333B (zh) | 2009-11-26 | 2014-11-19 | 本田技研工业株式会社 | 消失模具铸造法 |
JP6235448B2 (ja) * | 2014-12-02 | 2017-11-22 | 花王株式会社 | 消失模型用塗型剤組成物 |
-
2014
- 2014-11-19 JP JP2014234455A patent/JP6231465B2/ja active Active
-
2015
- 2015-10-21 WO PCT/JP2015/079751 patent/WO2016080139A1/ja active Application Filing
- 2015-10-21 US US15/520,009 patent/US10099274B2/en active Active
- 2015-10-21 CN CN201580062100.XA patent/CN107107166B/zh active Active
- 2015-10-21 KR KR1020177012566A patent/KR101950125B1/ko active IP Right Grant
- 2015-10-21 DE DE112015005231.3T patent/DE112015005231B4/de active Active
- 2015-11-09 TW TW104136872A patent/TWI592229B/zh not_active IP Right Cessation
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPS63183744A (ja) * | 1987-01-26 | 1988-07-29 | Nabeya:Kk | 多孔性鋳造品の製造方法 |
JPH01266941A (ja) * | 1988-04-20 | 1989-10-24 | Mitsubishi Heavy Ind Ltd | 消失模型用塗型剤 |
JP2003290873A (ja) * | 2002-04-08 | 2003-10-14 | Kao Corp | 消失模型鋳造法 |
Also Published As
Publication number | Publication date |
---|---|
TWI592229B (zh) | 2017-07-21 |
US20170312811A1 (en) | 2017-11-02 |
KR101950125B1 (ko) | 2019-02-19 |
CN107107166B (zh) | 2019-04-19 |
DE112015005231T5 (de) | 2017-08-24 |
KR20170068541A (ko) | 2017-06-19 |
DE112015005231B4 (de) | 2022-11-24 |
CN107107166A (zh) | 2017-08-29 |
JP2016097415A (ja) | 2016-05-30 |
US10099274B2 (en) | 2018-10-16 |
TW201637751A (zh) | 2016-11-01 |
JP6231465B2 (ja) | 2017-11-15 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP6470141B2 (ja) | 消失模型鋳造方法 | |
Ben Saada et al. | Assessment of the effect of 3D printed sand mold thickness on solidification process of AlSi13 casting alloy | |
JP6231465B2 (ja) | 消失模型鋳造方法 | |
JP2010052019A (ja) | 砂型鋳物のシミュレーション方法 | |
WO2016080132A1 (ja) | 消失模型鋳造方法 | |
WO2012104096A1 (en) | Sand additives for molds/cores for metal casting | |
JP6014087B2 (ja) | 消失模型鋳造方法 | |
Weise et al. | New core technology for light metal casting | |
Peters et al. | Effect of mould expansion on pattern allowances in sand casting of steel | |
JP2018058103A (ja) | 押湯形成体及びその押湯形成体を用いた鋳物の製造方法 | |
WO2016088517A1 (ja) | 浮力伝達治具 | |
JP2021016896A (ja) | 横穴の鋳抜き可否評価方法 | |
JP2017177217A (ja) | 消失模型鋳造方法 | |
Anggono et al. | Casting design, simulation and manufacturing validation of air compressor fan blade | |
JP6605305B2 (ja) | 鋳造方法 | |
BOČKUS et al. | Investigation of Ductile Casting Iron Risers in the Simulation Method | |
JP2018196889A (ja) | 中子の変形量予測方法 | |
US20090000756A1 (en) | Reducing residual stresses during sand casting |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 15860486 Country of ref document: EP Kind code of ref document: A1 |
|
WWE | Wipo information: entry into national phase |
Ref document number: 15520009 Country of ref document: US |
|
ENP | Entry into the national phase |
Ref document number: 20177012566 Country of ref document: KR Kind code of ref document: A |
|
WWE | Wipo information: entry into national phase |
Ref document number: 112015005231 Country of ref document: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 15860486 Country of ref document: EP Kind code of ref document: A1 |