CN213944774U - Casting structure of large-scale thick section cylinder barrel ductile iron - Google Patents
Casting structure of large-scale thick section cylinder barrel ductile iron Download PDFInfo
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- CN213944774U CN213944774U CN202021621410.5U CN202021621410U CN213944774U CN 213944774 U CN213944774 U CN 213944774U CN 202021621410 U CN202021621410 U CN 202021621410U CN 213944774 U CN213944774 U CN 213944774U
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Abstract
A casting structure of a large thick-section cylinder barrel ductile iron piece comprises a casting cavity and a pouring mechanism communicated with the casting cavity, wherein the casting cavity is formed by a part A casting mold, a part B casting mold, a part C casting mold and a part D casting mold in a segmented manner; the cavity body comprises a cylindrical first body and a second body, wherein the outer diameter of the second body is larger than that of the first body; the front end of the second body is provided with an annular boss, the outer diameter of the annular boss is smaller than that of the second body, and the inner diameter of the annular boss is equal to that of the first body; the part A casting mold comprises a lower sand box forming a second body and an annular boss, a sand core is arranged in the lower sand box, and the part B casting mold and the part C casting mold are sequentially connected and sleeved outside the sand core to form a first body; the D part casting mold is arranged on the C part casting mold and comprises a cope flask for plugging the upper end face of the first body. The casting mold is easy to manufacture and is not easy to have casting defects such as shrinkage cavity, shrinkage porosity, sand inclusion and the like.
Description
Technical Field
The application relates to the technical field of casting of large-scale thick section cylinder barrel ductile iron pieces, in particular to a casting structure of a large-scale thick section cylinder barrel ductile iron piece (the blank weight is 10500Kg, the pouring weight is 11000Kg, the external dimension phi 1350mm (phi 1170mm) x internal dimension phi 920mm x 3290mm, and the maximum wall thickness is 125 mm).
Background
The nodular cast iron is a high-strength cast iron material developed in the fifties of the twentieth century, and the main manufacturing process is to obtain spheroidal graphite through spheroidization and inoculation treatment so as to effectively improve the mechanical properties of the cast iron, particularly the plasticity and the toughness, and further obtain the strength higher than that of carbon steel. Because the comprehensive performance of the alloy is close to that of steel, the alloy is successfully used for casting parts with complex stress and higher requirements on strength, toughness and wear resistance, including important fields of automobiles, bridges, war industry, wind power, nuclear power and the like.
The heavy section nodular cast iron is nodular cast iron with the wall thickness of more than or equal to 100mm, and the core of the casting is slow in cooling speed and long in solidification time during the forming process, so that various defects such as poor spheroidization, graphite distortion, element segregation, slag inclusion, air holes, carbide segregation, shrinkage porosity and the like are easy to occur, and the popularization and the application of high-end nodular cast iron are influenced by different degrees. The cooling process and the smelting process are main factors influencing the structure performance of the large-section casting, and the cooling speed of the casting is accelerated by adopting a forced cooling mode through strictly controlling the chemical components of the raw materials, so that the effective measure for improving the structure performance of the large-section nodular cast iron is also accepted and applied by enterprises. The conventional methods for increasing the cooling speed are adding external chilling block, forced cooling, and the combination of chilling block and forced cooling, and these methods have been used to some extent in industrial production.
As shown in fig. 1, a cylinder ductile iron casting (which can also be regarded as a cavity of the casting) of large-scale heavy and large-section ductile iron is processed, the casting comprises a casting body a ', the casting body is composed of a hollow cylindrical casting first body a 1' and a casting second body a2 'which is arranged at the end part of the casting first body and has an outer diameter larger than that of the first body, a casting annular boss a 3' is arranged at the front end of the second body, the outer diameter of the annular boss is smaller than that of the second body, and the inner diameter of the annular boss is equal to that of the first body; 10500Kg of blank weight of the casting, 11000Kg of pouring weight, outer diameter phi 1350mm (phi 1170mm) of external dimension phi, inner diameter phi 920mm multiplied by 3290mm of external dimension and maximum wall thickness 125 mm; although the casting has a simple structure, the casting is required to have no casting defects such as shrinkage cavity, shrinkage porosity and the like in the casting process due to the specific large size and the specific nodular cast iron material, and the inner hole has machining roughnessThe casting difficulty is great. The traditional casting method comprises 3 casting methods, one is flat casting, the position of an inner pouring gate is designed with certain difficulty, molten iron is not stable, entrainment and shrinkage cavity and other casting defects are easily caused by entrainment, the consistency of the material of a circular cross section cannot be ensured, so that the surface of an inner hole can have a negative and positive surface, and the machining roughness of the inner hole cannot be metThe requirements of (1); the other method is vertical casting, because the height is too high, the mold drawing slope of the external mold is too high, if the external mold is used for core pulling, the mold is difficult to manufacture, the service life of the mold is also influenced, in addition, the casting mold is high, the sand core is long, and the core is difficult to be placed in a box; the third kind is horizontal and vertical casting, which solves the problems of unstable molten iron feeding and box matching for the lower core, but because the sand core of the inner hole is too long, the casting mold needs to be erected and then translated to the casting site after the box matching has been completedThe casting mould has great difficulty, and once the inner sand core is deviated during the erection and translation of the casting mould, the broken sand or broken sand blocks which are knocked off enter the casting mould to cause casting scrap.
SUMMERY OF THE UTILITY MODEL
The application is directed against the above-mentioned not enough of prior art, provides the gating system of the casting mould easy preparation, be difficult for appearing casting defects such as shrinkage cavity, shrinkage porosity, sand inclusion large-scale thick section cylinder barrel ductile iron spare.
In order to solve the technical problem, the technical scheme adopted by the application is as follows: a casting structure of a large thick-section cylinder barrel ductile iron piece comprises a casting cavity and a pouring mechanism communicated with the casting cavity, wherein the casting cavity comprises a cavity body, and the cavity body is formed by a part A casting mold, a part B casting mold, a part C casting mold and a part D casting mold in a segmented manner; the cavity body comprises a cylindrical first body and a second body, wherein the outer diameter of the second body is larger than that of the first body; the front end of the second body is provided with an annular boss, the outer diameter of the annular boss is smaller than that of the second body, and the inner diameter of the annular boss is equal to that of the first body; the part A casting mold comprises a lower sand box forming a second body and an annular boss, a sand core is arranged in the lower sand box, and the part B casting mold and the part C casting mold are sequentially connected and sleeved outside the sand core to form a first body; the D part casting mold is arranged on the C part casting mold and comprises a cope flask for plugging the upper end face of the first body.
By adopting the structure, the casting structure of the whole large-scale thick-section cylinder barrel ductile iron piece is divided into four sections, an A part casting mold (a drag flask) is firstly manufactured, the A part casting mold (the drag flask) is hoisted and moved to a casting site, the A part casting mold is flatly laid by the bottom pad, the core shell is placed on the plane of the A part casting mold by taking the annular convex table surface and the second body surface formed by the A part casting mold as the inner hole core shell positioning surface, and then the whole sand core forming the inner hole of the casting is directly manufactured on the A part casting mold by sand discharging; then the B part casting mold and the C part casting mold respectively penetrate through the sand cores and are placed on the A part casting mold, the D part casting mold is placed on the C part casting mold, and the A part casting mold, the B part casting mold, the C part casting mold and the D part casting mold are fixedly arranged to form a complete casting structure.
Preferably, a plurality of chilling blocks are axially arranged in the sand core, and the distance between the chilling blocks and the inner wall of the first body is smaller than the distance between the chilling blocks and the center shaft of the sand core; by adopting the structure, a plurality of chilling blocks are placed in the sand core in advance and are closer to the first body of the casting cavity, so that the cooling speed can be increased, and the requirement on the processing roughness of the inner hole is metThe requirements of (1).
Preferably, the distance between the chilling block and the inner wall of the first body is 10-50 mm, and the distance is too small, so that a sand layer at the position of the sand core is easy to fall off, the distance is too large, and the cooling effect is not good.
Preferably, the part B casting mold and the part C casting mold are both made of nodular cast iron molds; the wall thickness of the nodular cast iron mold is 0.8-2.0 times of that of the first body; by adopting the structure, because the height of the casting is high, the casting molds B and C in the middle are suspended, which is not beneficial to molding and fixing of the sand box, and the cast iron mold directly cast can realize convenient assembly and disassembly and convenient transportation, and can play a role in cooling the iron liquid of the casting; and the reasonable wall thickness setting can also prevent the influence of the high-temperature casting iron liquid on the B part casting mold and the C part casting mold.
Preferably, the matching surfaces of the part B casting mold and the part C casting mold are provided with a semicircular groove and a concave-convex matching surface for accommodating the sealing mud strip; by adopting the structure, the matching surfaces of the B part casting mold and the C part casting mold can be effectively sealed, the iron liquid is prevented from seeping or leaking, and in addition, the purpose of facilitating demolding can be achieved by the arrangement of the concave-convex matching surfaces; and 3 mm-5 mm draft angles are arranged on one side of the inner holes of the part B casting mold and the part C casting mold.
Preferably, the casting molds B and C (collectively referred to as iron molds) are preheated to 200-400 ℃ before use, and then are mixed with 25% of graphite coating and 75% of zircon powder coating produced by pressure spraying Ningbo Yongji to form the water-based coating. The preheating in advance prevents the B part casting mold and the C part casting mold from deforming and cracking due to large contact temperature difference with molten iron, and the temperature is very proper, because when the temperature of the iron mold is too high, the evaporation amount of water in the coating is increased, and the coating is peeled off in a large area after being hung and coated; when the temperature of the iron mold is too low, moisture cannot be fully volatilized, and the moisture is quickly escaped when the iron mold is subjected to thermal shock after casting, so that the coating is cracked, and moisture and coating fragments enter a casting, thereby generating casting defects.
Preferably, the pouring mechanism comprises a sprue and an ingate; the sprue comprises a first sprue and a second sprue, the first sprue and the second sprue are communicated through a transverse transition runner, the first sprue and the second sprue are axially and parallelly arranged with the first body, the ingate is located below the second body and comprises a first ingate communicated with the second sprue, and two ends of the first ingate are communicated with a third ingate through the second ingate and are communicated with a discharge port of the third ingate and the end face of the annular boss.
By adopting the structure, the pouring gate is communicated with the annular boss of the casting cavity, the sprue is divided into two sections, and the transverse transition pouring gate is arranged between the two sections, so that the stability of molten iron is ensured; the molten iron of the casting runs upwards from the bottom of the whole casting cavity gradually, the temperature of the molten iron in the cavity is balanced, the molten iron is stably and quickly filled in the cavity, the production cost is saved, and the casting system realizes the technical effects of large flow, low flow rate, stable and clean filling and furthest reduces the casting defects of slag inclusion, gas shrinkage cavity and the like.
Preferably, the first sprue comprises a large-diameter sprue part and a small-diameter sprue part, the large-diameter sprue part and the small-diameter sprue part are in transition connection through a reducing sprue, and the large-diameter sprue part is positioned above the small-diameter sprue part; by adopting the structure, the large flow of molten iron can be ensured to enter the runner system, and then the running flow rate of the molten iron is slowed down by the arrangement of the reducing sprue, so that the molten iron can enter the casting cavity more stably, and the casting defects such as slag inclusion, shrinkage cavity and the like are further reduced.
Preferably, the second ingate is a variable-diameter ingate, the large-diameter end of the variable-diameter ingate is communicated with the first ingate, and the small-diameter end of the variable-diameter ingate is communicated with the third ingate through a three-way ingate; by adopting the structure, the running flow speed of the molten iron can be slowed down again before the molten iron enters the casting cavity, so that the molten iron can enter the casting cavity more stably, and the casting defects such as slag inclusion, shrinkage cavity and the like are further reduced.
Preferably, the ratio of the sigma-delta large-diameter sprue part to the sigma-delta second sprue to the sigma-delta third ingate is 1: 0.55-0.85: 1.20-5.00; by adopting the ratio of the total cross-sectional areas of the inner diameters of the various runners, the technical effects of large flow, low flow rate, stable and clean mold filling can be effectively realized.
Preferably, the number of the second ingates is two, and the two second ingates are respectively positioned at two ends of the first ingate; the third ingates are two and are arranged in parallel and are vertically communicated with the second ingate through the three-way ingate, and each third ingate is provided with two discharge ports which are respectively communicated with the annular bosses. By adopting the structure, the iron liquid is provided for the casting cavity by the four feeding holes, and the four feeding holes are distributed at four positions of the annular boss, so that the feeding balance of the iron liquid in the cavity is better, the casting defect is reduced, and the processing roughness is ensuredThe requirements of (1).
Preferably, the straight pouring channel and the inner pouring channel are both pouring channels made of refractory ceramics.
Preferably, the cross sections of the straight pouring channel and the inner pouring channel are circular surfaces.
Drawings
FIG. 1 is a schematic structural diagram of a cylinder ductile iron casting of large-scale heavy section ductile iron according to the present application.
As shown in the attached drawings: a 'casting body, a 1' casting first body, a2 'casting second body, a 3' casting annular boss.
FIG. 2 is a schematic structural view of a cylinder ductile iron casting cavity of the present application.
FIG. 3 is a schematic view of the gating system of the present application.
Fig. 4 is a schematic structural view of the pouring mechanism of the present application.
FIG. 5 is a schematic view of a portion of a casting cavity of the present application and a portion of a pouring mechanism in communication therewith.
FIG. 6 is a schematic structural view of a portion of the pouring mechanism of the present application in communication with an end of a casting cavity.
FIG. 7 is a schematic structural view of a cast structure of a casting of the present application.
Fig. 8 is a schematic structural view of the sand core casting structure of the present application.
Fig. 9 is a schematic structural view of a ductile iron mold for forming a part B mold and a part C mold according to the present invention.
FIG. 10 is a schematic structural view showing that a part B mold and a part C mold are formed with draft on one side.
Fig. 11 is a schematic view of a partially enlarged view of fig. 9 of the present application.
FIG. 12 is a schematic structural view of a transverse cross-section of a sand core of the present application (see chill).
As shown in the attached drawings: a. the die cavity comprises a die cavity body, a1. a first body, a2 a second body, a3. annular bosses, b a sprue, b1 a first sprue, b11 a large-diameter sprue part, b12 a small-diameter sprue part, b13 a variable-diameter sprue, b2. a second sprue, b3. a transverse transition sprue, c an ingate, c1 a first ingate, c2. a second ingate, c3. a third ingate, c4. a three-way ingate and a discharge port c5.; the casting method comprises the following steps of 1, A part of casting mold, 2, B part of casting mold, 3, C part of casting mold, 4, D part of casting mold, 4.1 part of cope flask, 4.2 part of safety riser, 5 part of sand core, 6 part of semicircular groove, 7 part of concave matching surface, 8 part of convex matching surface and 9 part of chill.
Detailed Description
The drawings and the following description depict specific embodiments of the application to teach those skilled in the art how to make and use the best mode of the application. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that are considered to fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple variations of the present application. Thus, the present application is not limited to the specific embodiments described below, but only by the claims and their equivalents. The axial or circumferential or up-down, left-right, front-back and other position limitations of the present application are all in the direction shown in the drawings, so as to describe the technical scheme of the present application more clearly, and cannot be used to limit the protection scope of the present application.
The naming and description of the components of the following embodiments of the present application, including left, right, front, rear, first, second, etc., are defined by the directions shown in the drawings, and are only for clearly showing the inventive concepts of the present application, clearly showing the technical solutions of the present application, and are not used to limit the protection scope of the present application.
The casting cavity is a hollow cavity filled with the molten iron of the casting, and the shape of the hollow cavity is matched with the contour of the casting, so that all parts of the casting mentioned in the application can be equal to all parts of the casting cavity in order to express the inventive concept and technical scheme of the application more clearly and avoid ambiguity.
As shown in the accompanying drawings 2 and 7, the casting structure of the large thick-section cylinder barrel ductile iron piece comprises a casting cavity and a pouring mechanism communicated with the casting cavity, wherein the casting cavity comprises a cavity body, and the cavity body is formed by a part A casting mold 1, a part B casting mold 2, a part C casting mold 3 and a part D casting mold 4 in a segmented manner; the cavity body a comprises a first cylindrical body a1, and the outer diameter of the end part of the first body is larger than that of a second body a2 of the first body; an annular boss a3 is arranged at the front end of the second body, the outer diameter of the annular boss is smaller than that of the second body, and the inner diameter of the annular boss is equal to that of the first body; the A part of the casting mold comprises a drag flask 1.1 which forms a second body a2 and an annular boss a3, a sand core 5 is arranged in the drag flask, and the B part of the casting mold and the C part of the casting mold are sequentially connected and sleeved outside the sand core to form a first body; the part D casting mould is arranged on the part C casting mould and comprises a cope flask 4.1 for plugging the upper end face of the first body. As can be seen from fig. 7, a part of the pouring mechanism of the present application is fixed by the bottom drag flask, and the sprue part is also set up on one side of the cavity of the cylinder ductile iron member by the flask molding and extends in the axial direction.
By adopting the structure, the casting structure of the whole large-scale thick-section cylinder barrel ductile iron piece is divided into four sections, an A part casting mold (a drag flask) is firstly manufactured, the A part casting mold (the drag flask) is hoisted and moved to a casting site, the A part casting mold is flatly laid by the bottom pad, the core shell is placed on the plane of the A part casting mold by taking the annular convex table surface and the second body surface formed by the A part casting mold as the inner hole core shell positioning surface, and then the whole sand core forming the inner hole of the casting is directly manufactured on the A part casting mold by sand discharging; then the B part casting mold and the C part casting mold respectively penetrate through the sand cores and are placed on the A part casting mold, the D part casting mold is placed on the C part casting mold, and the A part casting mold, the B part casting mold, the C part casting mold and the D part casting mold are fixedly arranged to form a complete casting structure.
As shown in the accompanying drawings 8 and 12, a plurality of chilling blocks 9 are axially arranged in the sand core 5, and the distance between the chilling blocks and the inner wall of the first body is smaller than the distance between the chilling blocks and the central axis of the sand core; as can be seen from fig. 8, the chills of the present application are all vertically arranged along the axial direction, and as shown in fig. 12, a plurality of rows are uniformly distributed along the circumferential direction of the sand core, and the distance between the chills in adjacent rows is 0mm to 25 mm; by adopting the structure, a plurality of chilling blocks are placed in the sand core in advance and are closer to the first body of the casting cavity, so that the cooling speed can be increased, and the requirement on the processing roughness of the inner hole is metThe requirements of (1).
Specifically, as shown in fig. 8, the distance between the chill and the inner wall of the first body is 10mm to 50mm, i.e., d in the drawing, and this interval range is selected because if the distance is too small, the sand layer at the sand core is easy to fall off, the distance is too large, and the cooling effect is not good. The distance here refers to a straight line distance from the center position of the outer wall of the cold mold to the outermost wall of the sand core.
Specifically, as shown in fig. 9, in the present application, the part B casting mold and the part C casting mold are made of nodular cast iron molds, that is, the part B casting mold and the part C casting mold are used by directly casting a formed part made of cast iron material without sand box casting; the wall thickness of the nodular cast iron mold is 0.8-2.0 times of the wall thickness of the first body (namely the thickness of a casting cavity at the position of the first body of the casting); by adopting the structure, because the height of the casting is high, the casting molds B and C in the middle are suspended, which is not beneficial to molding and fixing of the sand box, and the cast iron mold directly cast can realize convenient assembly and disassembly and convenient transportation, and can play a role in cooling the iron liquid of the casting; and the reasonable wall thickness setting can also prevent the influence of the high-temperature casting iron liquid on the B part casting mold and the C part casting mold.
Specifically, as shown in fig. 9 and 11, the mating surfaces of the part B casting mold and the part C casting mold are provided with a semicircular groove 6 for accommodating a sealing mud strip, a concave mating surface 7 and a convex mating surface 8; wherein the concave matching surface 7 and the convex matching surface 8 are matched with each other when the B part casting mould and the C part casting mould are assembled; in addition, as shown in fig. 9, the outer side walls of the part B casting mold and the part C casting mold are provided with lifting lugs and mounting through holes which are in clamping fit with the lifting lugs and the part C casting mold, and specific figures are not shown; the lifting lugs can facilitate the lifting and the carrying of the casting mold, and the mounting through holes facilitate the assembly of the casting mold and the casting mold; the thickness or wall thickness of the ductile iron mold forming the part B casting mold and the part C casting mold does not include the positions provided with the lifting lugs or the mounting through holes; by adopting the structure, the matching surfaces of the B part casting mold and the C part casting mold can be effectively sealed, the iron liquid is prevented from seeping or leaking, and in addition, the purpose of facilitating demolding can be achieved by the arrangement of the concave-convex matching surfaces; in addition, the inner holes of the part B casting mold and the part C casting mold are made into single-side draft angles of 3 mm-5 mm, specifically, reference can be made to B in the attached drawing 10, which indicates that the specific size position of the single-side 3 mm-5 mm draft angle of the inner hole, namely, the inner wall of the upper end of the part C casting mold expands inwards by 3 mm-5 mm to form a taper molding with the inner wall gradually reduced from bottom to top, the extension direction of the inclined line forming the taper is from the lowest end of the inner wall of the part B casting mold to the top end of the inner side of the part C casting mold, and the inclination angles of the inner walls of the part B casting mold and the part C casting mold are gradually; the setting of the draft angle can not influence the wall thickness of the casting, so that when demoulding is facilitated, when the B part casting mould and the C part casting mould are in an upward walking process and are limited by the taper, the B part casting mould and the C part casting mould can be separated very conveniently, the casting reduces the contact surface between the mould and the casting, and the influence on the outer wall of the casting is avoided; and the wall thickness that the foundry goods is excessive because of this kind of draft can calculate into in advance as the machining allowance, and the foundry goods that the later stage obtained is got rid of through aftertreatment such as polishing etc..
Preferably, the casting molds B and C (collectively referred to as iron molds) are preheated to 200-400 ℃ before use, and then are mixed with 25% of graphite coating and 75% of zircon powder coating produced by pressure spraying Ningbo Yongji to form water-based coating; the water-based paint is coated on the inner walls of the casting molds B and C, and the coating thickness is 0.6-2.0 mm; the preheating in advance prevents the B part casting mold and the C part casting mold from deforming and cracking due to large contact temperature difference with molten iron, and the temperature is very proper, because when the temperature of the iron mold is too high, the evaporation amount of water in the coating is increased, and the coating is peeled off in a large area after being hung and coated; when the temperature of the iron mold is too low, moisture cannot be fully volatilized, and the moisture is quickly escaped when the iron mold is subjected to thermal shock after casting, so that the coating is cracked, and moisture and coating fragments enter a casting, thereby generating casting defects. 0.6 mm-2.0 mm, which is mainly used for protecting the iron mould and facilitating the iron mould to be taken out of the casting.
Specifically, as shown in fig. 7, a plurality of safety risers are installed in the cope flask, and the upper end of the sprue is as high as the safety risers; by adopting the structure, the safety riser can effectively solve the defect of air holes; the height of the upper port of the sprue and the height of the safety riser can ensure that no molten iron exists in the sprue cup or the quantitative ladle, so that the sprue cup or the quantitative ladle is convenient to move; of course, the upper end port of the sprue may be formed to have the same height as the mold of the section C.
Specifically, as shown in fig. 2-4, the pouring mechanism includes a sprue b and an ingate c; the sprue comprises a first sprue b1 and a second sprue b2, the first sprue and the second sprue are communicated through a transverse transition sprue b3, the first sprue and the second sprue are axially and parallelly arranged with the first body, the ingate c is located below the second body and comprises a first ingate c1 communicated with the second sprue, two ends of the first ingate are communicated with a third ingate c3 through the second ingate c2, and a discharge hole of the third ingate is communicated with the end face of the annular boss.
By adopting the structure, the pouring gate is communicated with the annular boss of the casting cavity, the sprue is divided into two sections, and the transverse transition pouring gate is arranged between the two sections, so that the stability of molten iron is ensured; the molten iron of the casting runs upwards from the bottom of the whole casting cavity gradually, the temperature of the molten iron in the cavity is balanced, the molten iron is stably and quickly filled in the cavity, the production cost is saved, and the casting system realizes the technical effects of large flow, low flow rate, stable and clean filling and furthest reduces the casting defects of slag inclusion, gas shrinkage cavity and the like.
As shown in fig. 4, the first sprue b1 described in this application includes a large-diameter sprue part b11 and a small-diameter sprue part b12, the large-diameter sprue part and the small-diameter sprue part are transitionally connected by a variable-diameter sprue b13, the large-diameter sprue part is located above the small-diameter sprue part, that is, the large-diameter sprue part is an inlet section of molten iron, and the pouring process is performed in a manner that an annular boss in a casting cavity is located below and a first body is located above, which can be specifically shown in fig. 3; by adopting the structure, the large flow of molten iron can be ensured to enter the runner system, and then the running flow rate of the molten iron is slowed down by the arrangement of the reducing sprue, so that the molten iron can enter the casting cavity more stably, and the casting defects such as slag inclusion, shrinkage cavity and the like are further reduced.
As an embodiment of the present application, the second ingate c2 is a variable diameter ingate, a large diameter end of the variable diameter ingate is communicated with the first ingate c1, and a small diameter end of the variable diameter ingate is communicated with the third ingate through a three-way ingate c 4; by adopting the structure, the running flow speed of the molten iron can be slowed down again before the molten iron enters the casting cavity, so that the molten iron can enter the casting cavity more stably, and the casting defects such as slag inclusion, shrinkage cavity and the like are further reduced. In the application, the ratio of the sigma-delta large-diameter sprue part to the sigma-delta second sprue to the sigma-delta third ingate is 1: 0.55-0.85: 1.20-5.00; by adopting the ratio of the total cross-sectional areas of the inner diameters of the various runners, the technical effects of large flow, low flow rate, stable and clean mold filling can be effectively realized.
As shown in fig. 4 and 6, the number of the second ingate c2 is two, and the two ingates are respectively positioned at two ends of the first ingate c 1; the third ingates are two and are arranged in parallel and are vertically communicated with the second ingate through the three-way ingate, each third ingate is provided with two discharge ports c5, and the discharge ports are formed in a mode of being vertical to the third ingate as shown in the attached drawing, so that the third ingate is axially parallel to the casting cavity, and molten iron can conveniently enter the cavity and is respectively communicated with the annular bosses.
In the present application, in order to reduce the sand washing defect, the sprue and the ingate are all made of refractory ceramic tubes. The minimum sectional area is arranged on the sprue, the sprue is partially bent at a right angle of 90 degrees by variable diameter, namely a transverse sprue, so that the sprue can be quickly filled with molten iron; by adopting the structure, the iron liquid is provided for the casting cavity by the four feeding holes, and the four feeding holes are distributed at four positions of the annular boss, so that the feeding balance of the iron liquid in the cavity is better, the casting defect is reduced, and the processing roughness is ensuredThe requirements of (1).
The cross sections of the straight pouring channel and the inner pouring channel are circular surfaces.
After the pouring system and the columns of all parts are fixed through a sand box, molten iron enters the pouring mechanism through a pouring gate on the sprue, and because the upper part of the first sprue is a large-diameter pipeline, the molten iron can be ensured to be quickly filled, and excessive air is prevented from entering; meanwhile, the reducing and transverse straight pouring channels are arranged, so that the flow velocity of molten iron can be slowed down, and the stability of the molten iron is ensured; the reducing is also arranged in the ingate, and four feed inlets with equal height are simultaneously arranged for feeding from the bottom of the casting cavity and further ensuring that the molten iron stably enters the casting cavityIn addition, casting defects are reduced, and the processing roughness is ensuredThe requirements of (1).
The specific overlap joint process of the casting structure of this application: firstly, dividing a casting mold forming a cavity body into 4 parts, as shown in fig. 7, including an a part casting mold 1, a B part casting mold 2, a C part casting mold 3 and a D part casting mold 4 (the four parts of the a part casting mold, the B part casting mold, the C part casting mold and the D part casting mold are sequentially connected from bottom to top, wherein a casting system structure of a fixed part is arranged in a sand box of the a part casting mold, and other parts of the casting system are also fixed by the sand box beside the casting mold forming the cavity body), wherein the a part casting mold is used as a lower sand box forming a second body and an annular boss, and the lower sand box is put into a sand box according to the molding of the cavity; then placing the core shell on the plane of the part A casting mold, and then placing sand to directly manufacture the whole sand core forming the casting inner hole on the part A casting mold; the end face of the second body and the end face of the annular boss in the part A casting mold are used as inner hole core shells (the core shells are made of high-temperature-resistant materials in the casting field, such as high-temperature-resistant ceramic materials and the like, and have the functions of supporting, parting and a base face for sand core casting), the core shells are placed on the plane of the part A casting mold, and then sand is placed to directly manufacture the whole sand core of the inner hole on the part A casting mold; in the process, the corresponding part of the casting structure is also put into the molding sand for fixation; then respectively putting the B part casting mold and the C part casting mold (ready-made iron mold structures) on the A part casting mold through sand cores, putting the D part casting mold on the C part casting mold, clamping and fixing the A part casting mold, the B part casting mold, the C part casting mold and the D part casting mold through a box placing mud strip and a steel plate and a bolt on a sand box outer frame to prevent molten iron leakage, and connecting and fastening the whole segmental casting mold; the casting mechanism or system is made up of ceramic tubes made of refractory material and is put into the molding sand while making the casting mould.
The casting mould with the special structure is simple to manufacture, saves materials and reduces the manufacturing cost of the mould.
Claims (10)
1. The utility model provides a casting structure of large-scale thick section cylinder barrel ductile iron spare which characterized in that: the structure comprises a casting cavity and a pouring mechanism communicated with the casting cavity, wherein the casting cavity is formed by a part A casting mold, a part B casting mold, a part C casting mold and a part D casting mold in a segmented manner; the casting cavity comprises a cavity body, the cavity body comprises a cylindrical first body and a second body, the outer diameter of the second body is larger than that of the first body, and the second body is arranged at the end part of the first body; the front end of the second body is provided with an annular boss, the outer diameter of the annular boss is smaller than that of the second body, and the inner diameter of the annular boss is equal to that of the first body; the part A casting mold comprises a lower sand box forming a second body and an annular boss, a sand core is arranged in the lower sand box, and the part B casting mold and the part C casting mold are sequentially connected and sleeved outside the sand core to form a first body; the D part casting mold is arranged on the C part casting mold and comprises a cope flask for plugging the upper end face of the first body.
2. The casting structure of the large thick-section cylinder barrel ductile iron piece according to claim 1, characterized in that: the sand core is provided with a plurality of chilling blocks along the axial direction, and the distance between the chilling blocks and the inner wall of the first body is smaller than the distance between the chilling blocks and the center shaft of the sand core.
3. The casting structure of the large thick-section cylinder barrel ductile iron piece according to claim 2, characterized in that: the distance between the chilling block and the interior of the first body is 10 mm-50 mm; all the chills are vertically arranged along the axial direction, and a plurality of rows of chills are uniformly distributed along the circumferential direction of the sand core, and the distance between the chills in the adjacent rows is 0-25 mm.
4. The casting structure of the large thick-section cylinder barrel ductile iron piece according to claim 1, characterized in that: the casting mold B and the casting mold C are all made of nodular cast iron molds; the wall thickness of the nodular cast iron mold is 0.8-2.0 times of the wall thickness of the first body.
5. The casting structure of the large thick-section cylinder barrel ductile iron piece according to claim 1, characterized in that: the matching surfaces of the B part casting mold and the C part casting mold are provided with a semicircular groove and a concave-convex matching surface for accommodating a sealing mud strip, and the single edge of the inner hole of the B part casting mold and the C part casting mold is provided with a pattern drawing slope of 3-5 mm.
6. The casting structure of the large thick-section cylinder barrel ductile iron piece according to claim 1, characterized in that: the inner walls of the part B casting mold and the part C casting mold are coated with water-based paint with the thickness of 0.6 mm-2.0 mm; the facility in the cope flask is provided with a plurality of safe risers, and the upper end opening of the sprue is as high as or higher than the safe risers.
7. The casting structure of the large thick-section cylinder barrel ductile iron piece according to claim 1, characterized in that: the pouring mechanism comprises a straight pouring gate and an inner pouring gate; the sprue comprises a first sprue and a second sprue, the first sprue and the second sprue are communicated through a transverse transition runner, the first sprue and the second sprue are axially and parallelly arranged with the first body, the ingate is located below the second body and comprises a first ingate communicated with the second sprue, and two ends of the first ingate are communicated with a third ingate through the second ingate and are communicated with a discharge port of the third ingate and the end face of the annular boss.
8. The casting structure of the large thick-section cylinder barrel ductile iron casting according to claim 7, wherein: the first sprue comprises a large-diameter sprue part and a small-diameter sprue part, the large-diameter sprue part and the small-diameter sprue part are in transition connection through a reducing sprue, and the large-diameter sprue part is positioned above the small-diameter sprue part; the second ingate is the reducing ingate, the large-diameter end of the reducing ingate is communicated with the first ingate, and the small-diameter end of the reducing ingate is communicated with the third ingate through the tee joint ingate.
9. The casting structure of the large thick-section cylinder barrel ductile iron casting according to claim 8, wherein: the ratio of the total internal diameter cross-sectional area Σ a of the large-diameter sprue portion, the second sprue, and the third ingate: the sigma A large-diameter sprue part, the sigma A second sprue and the sigma A third ingate are = 1: 0.55-0.85: 1.20-5.00.
10. The casting structure of the large thick-section cylinder barrel ductile iron casting according to claim 7, wherein: the two second ingates are respectively positioned at two ends of the first ingate; the third ingates are two and are arranged in parallel and are vertically communicated with the second ingate through a three-way ingate, and each third ingate is provided with two discharge ports which are respectively communicated with the annular bosses; the cross sections of the straight pouring channel and the inner pouring channel are circular surfaces; the straight pouring channel and the inner pouring channel are all pouring channels made of refractory ceramics.
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