A sand core for casting shell casting and casting process thereof

Abstract

The present invention relates to a sand core for casting a shell casting and a casting process thereof, wherein the shell is a planetary carrier; the sand core is divided into upper and lower cores, and is composed of an upper cover and a lower bottom made of coated sand, and a mold cavity corresponding to a vertical shell is formed between the upper cover and the lower bottom. The casting process of the shell casting comprises: 1) filling the mold; 2) solidification; the sand core is adopted, and the upper and lower molds are divided at the upper end of the upper cover and the lower bottom combination of the sand core; during the filling process, a semi-enclosed casting system is adopted, and the semi-enclosed casting system is composed of a straight runner, a horizontal runner and an inner runner, and the cross-sectional ratio of the straight runner, the horizontal runner and the inner runner is ΣFstraight:ΣFhorizontal:ΣFinally = 4:8:3; a vertical foam ceramic filter is arranged on the side of the straight runner, and the size of the filter is 75 mm×75 mm×22 mm, and the specification is 10 ppi.

Description

Technical Field

[0001] The invention relates to the technical field of casting, and in particular to a sand core for casting a shell casting and a casting process thereof. Background Art

[0002] For planet carrier castings, traditional sand cores are generally Hough type, with the core divided in half. Summary of the invention

[0003] In order to solve the above problems, the present invention proposes a sand core for casting a shell casting and a casting process thereof.

[0004] The technical solution of the present invention:

[0005] A sand core for pouring a shell casting, wherein the shell is a planetary carrier; the sand core is divided into upper and lower cores, which are composed of an upper cover and a lower bottom made of coated sand, and a cavity corresponding to the vertical planetary carrier is formed between the upper cover and the lower bottom.

[0006] The lower bottom includes a 1# core group, a 2# core group, and a 3# core group. The 2# core group extends through a hole set on the 1# core group and is positioned and connected with the 1# core group. The 3# core group is sleeved on the 2# core group, is positioned and connected with the 2# core group, and is supported on the 1# core group.

[0007] The upper cover is placed on the 1# core group, and covers the 2# core group and the 3# core group. The upper cover is positioned and connected to the 3# core group, and the upper end of the 2# core group extends out through a hole provided on the upper cover.

[0008] The outer wall of the upper cover has a thickness of 18-20mm, and a number of ribs are evenly distributed on the outer wall of the upper cover; the 2# core group is hollowed out to form a circular through hole that runs through the upper and lower ends of the 2# core group, and the circular through hole has a thickness of 18-20mm, and a number of ribs are evenly distributed in the circular through hole. This design reduces the weight of the sand core, reduces the cost of sand, and is very conducive to exhaust. At the same time, the ribs around the periphery ensure that the strength of the sand mold still meets the strength requirements.

[0009] The 2# core group includes a base and a columnar protrusion, the base is located below the columnar protrusion and is integrated with the columnar protrusion, the 1# core group is disc-shaped, the hole set on the 1# core group is a circular hole, and the 3# core group is ring-shaped.

[0010] The columnar protrusion extends through the hole set on the 1# core group, and the bottom bracket is supported under the 1# core group; the columnar protrusion is divided into upper and lower sections, the diameter of the upper section of the columnar protrusion is smaller than the diameter of the lower section, the 3# core group is sleeved on the lower section of the columnar protrusion, and the lower section of the columnar protrusion is provided with a first vertical groove penetrating the lower section of the columnar protrusion, and the inner walls of the 1# core group and the 3# core group are respectively provided with protrusions, and the two protrusions are assembled into a first protrusion, and the first protrusion is positioned and matched with the first vertical groove to position the 2# core group with the 1# core group and the 3# core group; the outer peripheral surface of the upper section of the columnar protrusion and the 3# core group together constitute the inner surface of the shell casting.

[0011] A plurality of second vertical grooves are evenly arranged around the inner wall of the upper cover, and the lower ends of the second vertical grooves are open. A plurality of second protrusions are evenly distributed around the outer circumference of the 3# core group, and the second protrusions correspond to the second vertical grooves one by one and are positioned and matched with the corresponding second vertical grooves. One of the second protrusions is provided with a third vertical groove that runs through the second protrusion above and below, and the corresponding second vertical groove is provided with a third protrusion, and the third protrusion is positioned and matched with the third vertical groove to position the upper cover and the 3# core group; the inner wall of the upper cover constitutes the outer surface of the shell casting.

[0012] The bottom support and the columnar protrusion are transitioned through an arc surface, and the lower opening of the circular hole of the 1# core group is an arc opening matching the arc surface.

[0013] The first vertical groove, the second vertical groove and the third vertical groove are all vertical grooves with a larger upper end and a smaller lower end.

[0014] The contact surface between the upper cover and the 1# core group is matched through a step to prevent the coated sand outside the sand core from entering the mold cavity during the pouring process; a waterproof ring is arranged on the top of the sand core so that the molten iron will not drill water during the filling process.

[0015] A casting process for a shell casting, the process comprising: 1) filling the mold; 2) solidification; using the above-mentioned sand core, and splitting the mold up and down at the upper end of the upper cover and lower bottom assembly of the sand core; separating the castings, and the sand core exhaust and casting pouring system shrinkage compensation are very good.

[0016] During the filling process, a semi-enclosed pouring system is adopted, which is composed of a sprue, a cross runner and an ingode, and the cross-sectional ratio of the sprue, the cross runner and the ingode is ΣFvertical:ΣFcross:ΣFinally=4:8:3, which is a first-level slag stop; a vertical foam ceramic filter is arranged on the side of the sprue, and the size of the filter is 75 mm×75 mm×22 mm, and the specification is 10 ppi, which is a second-level slag stop; the cross runner is a high and narrow sprue, and the ingode is a thin and wide ingode; a slag collection nest is arranged at the end of the cross runner, and a sprue nest is arranged at the lower end of the sprue; with this design, the ingode can be completely closed, and its mold flow analysis shows that the first stream of dirty molten iron enters the casting only after filling the slag collection nest and the cross runner, and the punching speed is basically the same, and the punching is stable without air vortex and slag inclusion; the two-stage slag stop can effectively prevent slag eyes in the casting, and obtain a smooth and beautiful casting.

[0017] The designed starting pouring temperature is 1440±10℃, the pouring time is 11~13 s, and the starting pouring temperature is designed to be 1440℃, which is 20-40℃ higher than the starting pouring temperature of similar products before. It can effectively promote gas overflow and facilitate shrinkage compensation to obtain dense castings.

[0018] There are two sand cores in total, which are arranged symmetrically, and the pouring system is constructed in the middle of the two sand cores.

[0019] The invention has the advantages of reasonable design and ingenious conception. The traditional half-type design of the sand core is abandoned and the upper and lower parting method is adopted. In this way, during pouring, the sand core is vented and the casting is compensated for shrinkage very well, and the shell casting obtained by pouring is easy to separate. The pouring process is further designed. During the filling process, the molten iron is filled stably without air entrainment and eddy current phenomena. During the solidification process, the compensation channel is unobstructed and continuous, and no isolated liquid phase area appears. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the connection between the sand core, pouring system and riser system.

[0021] Figure 2 It is a schematic diagram of the connection between the pouring system and the riser system.

[0022] Figure 3 Three-dimensional image of sand core.

[0023] Figure 4 It is a three-dimensional diagram of the upper cover.

[0024] Figure 5 It is a bottom three-dimensional diagram.

[0025] Figure 6 This is a three-dimensional diagram of the 1# core assembly.

[0026] Figure 7This is a three-dimensional diagram of the 2# core group.

[0027] Figure 8 This is a three-dimensional picture of the 3# core group.

[0028] In the figure, the sand core 1 comprises an upper cover 1-1, a lower bottom 1-2, a 1# core group 1-2-1, a 2# core group 1-2-2, a bottom support 1-2-2-1, a columnar protrusion 1-2-2-2, a 3# core group 1-2-3, a semi-enclosed pouring system 2, a sprue 2-1, a cross runner 2-2, and an inner runner 2-3. DETAILED DESCRIPTION

[0029] like Figure 3-8As shown, a sand core for casting a planet carrier casting, the sand core 1 is divided into upper and lower cores, which are composed of an upper cover 1-1 and a lower bottom 1-2 made of coated sand, and a cavity corresponding to a vertical shell is formed between the upper cover 1-1 and the lower bottom 1-2; the lower bottom 1-2 includes a 1# core group 1-2-1, a 2# core group 1-2-2, and a 3# core group 1-2-3, the 2# core group 1-2-2 extends through a hole set on the 1# core group 1-2-1, and is positioned and connected to the 1# core group 1-2-1, the 3# core group 1-2-3 is sleeved on the 2# core group 1-2-2, is positioned and connected to the 2# core group 1-2-2, and is supported on the 1# core group 1-2- 1; the upper cover is on the 1# core group 1-2-1, the upper cover covers the 2# core group 1-2-2 and the 3# core group 1-2-3, the upper cover 1-1 is positioned and connected with the 3# core group 1-2-3, and the upper end of the 2# core group 1-2-2 extends through the hole set on the upper cover 1-1; the outer wall of the upper cover 1-1 has a thickness of 18-20mm, and a plurality of ribs are evenly distributed on the outer wall of the upper cover 1-1; the 2# core group 1-2-2 is hollowed out into a circular through hole that runs through the upper and lower ends of the 2# core group 1-2-2, the circular through hole has a thickness of 18-20mm, and a plurality of ribs are evenly distributed in the circular through hole; The 2# core group 1-2-2 includes a bottom bracket 1-2-2-1 and a columnar protrusion 1-2-2-2. The bottom bracket 1-2-2-1 is located below the columnar protrusion 1-2-2-2 and is integrated with the columnar protrusion 1-2-2-2. The 1# core group 1-2-1 is disc-shaped, and the hole set on the 1# core group 1-2-1 is a round hole. The 3# core group 1-2-3 is annular; the columnar protrusion 1-2-2-2 extends through the hole set on the 1# core group 1-2-1, and the bottom bracket 1-2-2-1 is supported under the 1# core group 1-2-1; the columnar protrusion 1-2-2-2 is divided into upper and lower sections, and the columnar protrusion 1-2-2 -2 The diameter of the upper section is smaller than that of the lower section. The 3# core group 1-2-3 is sleeved on the lower section of the columnar protrusion 1-2-2-2. The lower section of the columnar protrusion 1-2-2-2 is provided with a first vertical groove penetrating the lower section of the columnar protrusion 1-2-2-2. The circular hole of the 1# core group 1-2-1 and the inner wall of the 3# core group 1-2-3 are respectively provided with protrusions. The two protrusions are assembled into a first protrusion. The first protrusion is positioned and matched with the first vertical groove to position the 2# core group 1-2-2 with the 1# core group 1-2-1 and the 3# core group 1-2-3. The outer peripheral surface of the upper section of the columnar protrusion 1-2-2-2 and the 3# core group 1-2-3 together constitute the inner surface of the shell casting.The inner wall of the upper cover 1-1 is evenly provided with a plurality of second vertical grooves around a circle, and the lower ends of the second vertical grooves are open. The outer circumference of the 3# core group 1-2-3 is evenly provided with a plurality of second protrusions around a circle, and the second protrusions correspond to the second vertical grooves one by one and are positioned and matched with the corresponding second vertical grooves. One of the second protrusions is provided with a third vertical groove running through the second protrusion, and the corresponding second vertical groove is provided with a third protrusion, and the third protrusion is positioned and matched with the third vertical groove, so as to position the upper cover 1-1 and the 3# core group 1-2-3. Core assembly 1-2-3; the inner wall of the upper cover 1-1 constitutes the outer surface of the shell casting; the bottom bracket 1-2-2-1 and the columnar protrusion 1-2-2-2 are connected by an arc surface, and the lower opening of the circular hole of the 1# core assembly 1-2-1 is an arc opening that matches the arc surface; the first vertical groove, the second vertical groove, and the third vertical groove are all vertical grooves with a large upper end and a small lower end; the contact surface between the upper cover 1-1 and the 1# core assembly 1-2-1 is matched by a step; a waterproof ring is provided on the top of the sand core 1. ;

[0030] like Figure 1 ,2 shows a casting process for a planetary carrier casting, the process comprising: 1) filling the mold; 2) solidification; using the above-mentioned sand core 1, and splitting the mold up and down at the upper end of the combination of the upper cover 1-1 and the lower bottom 1-2 of the sand core 1; in the filling process, a semi-enclosed casting system 2 is used, the semi-enclosed casting system 2 is connected by a sprue 2-1, a cross runner 2-2 and an inner runner 2-3, the cross-sectional ratio of the sprue 2-1, the cross runner 2-2 and the inner runner 2-3 is ΣFvertical:ΣFcross:ΣFinally = 4:8:3, which is a first-level slag stop; a vertically placed foam ceramic filter 2-4 is arranged on the side of the sprue 2-1, the size of the filter is 75 mm×75 mm×22 mm, and the specification is 10 ppi is a secondary slag stop; the cross runner 2-2 is a high and narrow cross runner, and the ingrowing 2-3 is a thin and wide ingrowing; a slag collecting nest is provided at the end of the cross runner 2-2, and a sprue nest is provided at the lower end of the straight runner 2-1; there are two sand cores 1, which are arranged symmetrically, and the pouring system 2 is constructed in the middle of the two sand cores 1.

[0031] The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A sand core for casting a shell casting, wherein the shell is a planet carrier; characterized in that: The sand core is divided into upper and lower cores, and is composed of an upper cover and a lower bottom made of coated sand, and a cavity corresponding to the vertical planet carrier is formed between the upper cover and the lower bottom; The lower bottom includes a 1# core group, a 2# core group, and a 3# core group. The 2# core group extends through a hole set on the 1# core group and is positioned and connected with the 1# core group. The 3# core group is sleeved on the 2# core group, is positioned and connected with the 2# core group, and is supported on the 1# core group. The upper cover is placed on the 1# core group, and covers the 2# core group and the 3# core group. The upper cover is positioned and connected to the 3# core group, and the upper end of the 2# core group extends out through a hole provided on the upper cover; The outer wall of the upper cover has a thickness of 18-20 mm, and a plurality of ribs are evenly distributed on the outer wall of the upper cover; The 2# core group is hollowed out to form a circular through hole that passes through the upper and lower ends of the 2# core group. The circular through hole has a wall thickness of 18-20 mm. A plurality of ribs are evenly distributed in the circular through hole. The 2# core group includes a bottom bracket and a columnar protrusion, the bottom bracket is located below the columnar protrusion and is integrated with the columnar protrusion, the 1# core group is disc-shaped, the hole set on the 1# core group is a circular hole, and the 3# core group is annular; The columnar protrusion extends through the hole set on the 1# core group, and the bottom bracket is supported under the 1# core group; the columnar protrusion is divided into upper and lower sections, the diameter of the upper section of the columnar protrusion is smaller than the diameter of the lower section, the 3# core group is sleeved on the lower section of the columnar protrusion, and the lower section of the columnar protrusion is provided with a first vertical groove penetrating the lower section of the columnar protrusion, and the inner walls of the 1# core group and the 3# core group are respectively provided with protrusions, and the two protrusions are assembled into a first protrusion, and the first protrusion is positioned and matched with the first vertical groove to position the 2# core group with the 1# core group and the 3# core group; the outer peripheral surface of the upper section of the columnar protrusion and the 3# core group together constitute the inner surface of the shell casting; A plurality of second vertical grooves are evenly arranged around the inner wall of the upper cover, and the lower ends of the second vertical grooves are open. A plurality of second protrusions are evenly arranged around the outer circumference of the 3# core group, and the second protrusions correspond to the second vertical grooves one by one and are positioned and matched with the corresponding second vertical grooves. One of the second protrusions is provided with a third vertical groove that runs through the second protrusion, and the corresponding second vertical groove is provided with a third protrusion, and the third protrusion is positioned and matched with the third vertical groove to position the upper cover and the 3# core group; the inner wall of the upper cover constitutes the outer profile of the shell casting; The bottom support and the columnar protrusion are connected by an arc surface, and the lower opening of the circular hole of the 1# core group is an arc opening matching the arc surface; The first vertical groove, the second vertical groove and the third vertical groove are all vertical grooves with a larger upper end and a smaller lower end; The upper cover and the contact surface of the 1# core group are matched through a step; a waterproof ring is arranged on the top of the sand core.

2. A casting process for a shell casting, the process comprising: 1) filling the mold; 2) solidification; characterized in that: The sand core described in claim 1 is used, and the upper end of the upper cover and lower bottom assembly of the sand core is divided into upper and lower molds; During the filling process, a semi-enclosed pouring system is used. The semi-enclosed pouring system is composed of a sprue, a cross runner and an ingode. The cross-sectional ratio of the sprue, the cross runner and the ingode is ΣFvertical:ΣFcross:ΣFinally = 4:8:3, which is a primary slag stop; a vertical foam ceramic filter is arranged on the side of the sprue, and the size of the filter is 75 mm×75 mm×22 mm, and the specification is 10 ppi, which is a secondary slag stop; the cross runner is a high and narrow sprue, and the ingode is a thin and wide ingode; a slag collection nest is arranged at the end of the cross runner, and a sprue nest is arranged at the lower end of the sprue; The design starting pouring temperature is 1440±10℃, and the pouring time is 11~13 s; There are two sand cores in total, which are arranged symmetrically, and the pouring system is constructed in the middle of the two sand cores.

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