Technology for casting large mine grinding I-shaped structure workpiece through foam yielding layer

Abstract

The invention belongs to the technical field of casting, and particularly discloses a technology for casting a large mine grinding I-shaped structure workpiece through a foam yielding layer, a pouring system, a casting cavity, a chilling block, the yielding layer and a sand core are included, the pouring system is communicated with the bottom of the casting cavity, a riser is formed in the upper end face of the casting cavity, and the riser is communicated with the casting cavity; a vertical sand core is arranged in the center of the casting cavity, the chilling blocks are arranged on the outer side wall of the middle of the casting cavity, the chilling blocks are distributed around the casting cavity in a multi-layer mode, and receding layers are arranged among the chilling blocks; according to the technology, a foam yielding layer is additionally arranged on the outer side of the hollow shaft, and in the casting process of a casting, the yielding layer is gasified to form a certain gap, so that the yielding property of a sand mold at the position is improved, and the occurrence probability of cracks on the inner side of an I-shaped structure is reduced; and meanwhile, due to the increase of the deformability of the sand mold, the shrinkage of the casting is facilitated, so that the size of the shrunk casting meets the process requirement, the production efficiency is improved, and the production cost is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of casting, and in particular relates to a technology for casting a large-scale I-shaped structure workpiece of a mining mill by using a foam yielding layer. Background Art

[0002] The hollow shaft is one of the important components of large-scale mining grinding equipment. Its structure is usually a cylindrical cavity on the inside and an I-shaped rotating body on the outside. In the commonly used casting method, in order to ensure the quality of the casting, a layered sand-hanging chiller is set in the middle of the outer I-shaped structure, so that the lower end of the casting is cooled first and the upper end of the casting is cooled later, thereby improving the yield of the casting and saving costs. However, when the I-shaped structure of the casting shrinks in the cast state, the placement of the chiller hinders the shrinkage of the casting. The casting does not have enough shrinkage space during the shrinkage process, which makes the internal structure of the casting prone to cracks and affects the overall size of the casting, increasing the subsequent maintenance costs. In severe cases, the casting is scrapped, increasing production costs and reducing production efficiency. Summary of the invention

[0003] In view of the problems existing in the background technology, the present invention provides a technology for casting a large-scale I-shaped structure workpiece of a mining mill by using a foam yielding layer.

[0004] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a technology for casting a large-scale I-shaped structure workpiece of a mining mill using a foam retreat layer, including a pouring system, a casting cavity, a chill, a retreat layer and a sand core, the pouring system is connected to the bottom of the casting cavity, a riser is provided on the upper end surface of the casting cavity, and the riser is connected to the casting cavity; a vertical sand core is provided at the center of the casting cavity, the chill is arranged on the outer wall of the middle part of the casting cavity, the chill is distributed in multiple layers around the casting cavity, and retreat layers are provided between the chills; the retreat layer is horizontally arranged between the chills, the retreat layer is made of foam material, the retreat layer is a circular ring structure, and the inner hole diameter of the retreat layer is larger than the outer diameter of the casting cavity.

[0005] The pouring system includes a gate, a sprue, a runner and an entgate; the lower end of the gate is connected to the sprue, and the lower end of the sprue is connected to the runner; the entgate is located below the casting cavity, the upper end of the entgate is connected to the bottom of the casting cavity, and the lower end of the entgate is connected to the runner.

[0006] The sand core is arranged on a sand core seat at the center bottom of the casting cavity, and a vent hole is arranged in the middle of the sand core.

[0007] A parting line is arranged at the upper end of the casting cavity, and the parting line divides the casting cavity into an upper box and a lower box; positioning holes are arranged on the contact surfaces of the upper box and the lower box, and the upper and lower positioning holes correspond to each other.

[0008] The riser is an annular structure, the outer diameter of the riser is larger than the outer diameter of the casting cavity, and the inner diameter of the riser is smaller than the inner diameter of the casting cavity.

[0009] The thickness of the retreat layer is not less than 30 mm.

[0010] The radius difference between the inner hole of the retreat layer and the outer diameter of the casting cavity is amm, 50<a<70.

[0011] Beneficial effects of the invention: The invention provides a technology for casting a large-scale I-shaped structure workpiece of a mining mill using a foamed yield layer. The technology adds a layer of foamed yield layer on the outside of the hollow shaft. During the casting process, the yield layer vaporizes to form a certain gap, thereby improving the yield of the sand mold at that location and reducing the probability of cracks on the inside of the I-shaped structure. At the same time, due to the increase in the yield of the sand mold at that location, it is beneficial to the shrinkage of the casting, so that the size of the casting after shrinkage meets the process requirements, thereby improving production efficiency and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the structure of the present invention.

[0013] Figure 2 This is a top view of BB.

[0014] Figure 3 This is a bottom view from BB.

[0015] Figure 4 This is the AA cross-section view.

[0016] In the figure: 1. gate, 2. sprue, 3. runner, 4. endogate, 5. casting cavity, 6. chill, 7. retreat layer, 8. positioning hole, 9. sand core, 10. riser, 11. upper box, 12. lower box. DETAILED DESCRIPTION

[0017] The technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in the specification. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0018] The following is combined with Figure 1-4The specific implementation mode of the present invention is further elaborated in detail: a technology for casting a large-scale I-shaped structure workpiece of a mining mill using a foam retreat layer, comprising a pouring system, a casting cavity 5, a chiller 6, a retreat layer 7 and a sand core 9, wherein the pouring system is connected to the bottom of the casting cavity 5, and the pouring system comprises a gate 1, a sprue 2, a runner 3 and an ingrown 4; the lower end of the gate 1 is connected to the sprue 2, and the lower end of the sprue 2 is connected to the runner 3; the ingrown 4 is located below the casting cavity 5, the upper end of the ingrown 4 is connected to the bottom of the casting cavity 5, and the lower end of the ingrown 4 is connected to the runner 3; in this embodiment, the runner 3 is located below the casting cavity 5 and is connected to the casting cavity 5 through the ingrown 4; the runner 3 can be a circular cavity located below the casting cavity 5; when the runner 3 is a circular cavity, there are multiple ingrowns 4, which are evenly distributed above the runner 3; The cross section of the casting cavity 5 is an "I"-shaped structure, and a riser 10 is provided on the upper end surface of the casting cavity 5, and the riser 10 is connected to the casting cavity 5; a vertical sand core 9 is provided at the center of the casting cavity 5, and the sand core 9 is arranged on a sand core seat at the bottom of the center of the casting cavity 5, and a vent hole is provided in the middle of the sand core 9; the riser 10 is an annular structure, and the outer diameter of the riser 10 is larger than the outer diameter of the casting cavity 5, and the inner diameter of the riser 10 is smaller than the inner diameter of the casting cavity 5. and is larger than the diameter of the vent hole of the sand core 9; a parting line is provided at the upper end of the casting cavity 5, and the parting line divides the casting cavity 5 into an upper box 11 and a lower box 12; a positioning hole 8 is provided on the contact surface of the upper box 11 and the lower box 12, and the upper and lower positioning holes 8 correspond to each other; in order to facilitate the casting of the sand mold, in this embodiment, the parting line is set at the connection between the middle and the upper end of the casting cavity 5; the positioning hole 8 is for the convenience of closing the box; the chill 6 is set on the outer side of the middle of the casting cavity 5 On the wall, cold irons 6 are distributed in multiple layers around the casting cavity 5, and retreat layers 7 are arranged between the cold irons 6; the retreat layers 7 are horizontally arranged between the cold irons 6, the retreat layers 7 are made of foam material, the retreat layers 7 are annular structures, and the inner hole diameter of the retreat layers 7 is larger than the outer diameter of the casting cavity 5; the thickness of the retreat layer 7 is not less than 30 mm; in this embodiment, according to the shape structure of the casting and the shrinkage ratio of the molten steel during the solidification process, it is calculated that when the thickness of the retreat layer 7 is not less than 30 mm, it can effectively play a role in assisting the shrinkage of the casting. In this example, the thickness of the retreat layer 7 is 30 mm; the radius difference between the inner hole of the retreat layer 7 and the outer diameter of the casting cavity 5 is amm, 50<a<70; it has been proved by experiments that in this embodiment, when a>50mm, the molten steel will not seep out; when a>70mm, when the casting shrinks, the retreat layer 7 cannot meet the design requirements. In this example, a=60mm is taken.

[0019] The use process of the present invention is as follows: first, a casting cavity 5 and a pouring system are made, and a riser 10 is arranged on the upper end surface of the casting cavity 5; wherein, chills 6 are arranged in layers on the outside of the side walls of the casting cavity 5, and a retreat layer 7 is arranged between the chills 6; after the casting model is made, molten steel is poured; the molten steel enters from the pouring gate 1, passes through the sprue 2, the runner 3 and the inner runner 4 in sequence, and then fills the mold from the bottom to the top from the lower end of the casting cavity 5; after the pouring is completed, the casting begins to cool; during the filling and cooling process, the molten steel will release a large amount of heat, vaporize the retreat layer 7, and form a gap in the retreat layer 7; when the casting is cooled, the casting will expand and contract with heat, and since the strength at the retreat layer 7 after vaporization is the lowest, when the casting shrinks, the sand mold here will collapse to a certain extent, forming a gap, which is convenient for the casting to shrink, thereby avoiding cracks and dimensional deviations generated in the casting during the shrinkage process.

[0020] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0021] Parts of the present invention not described in detail are prior art.

Claims

1. A technology for casting a large-scale I-shaped structure workpiece of a mining mill using a foamed yielding layer, comprising a pouring system, a casting cavity (5), a chiller (6), a yielding layer (7) and a sand core (9), wherein: The pouring system is connected to the bottom of the casting cavity (5), and a riser (10) is provided on the upper end surface of the casting cavity (5), and the riser (10) is connected to the casting cavity (5); a vertical sand core (9) is provided at the center of the casting cavity (5), and the chill (6) is arranged on the outer wall of the middle part of the casting cavity (5), and the chill (6) is distributed in multiple layers around the casting cavity (5), and a retreat layer (7) is provided between the chills (6); the retreat layer (7) is horizontally arranged between the chills (6), the retreat layer (7) is made of foam material, and the retreat layer (7) is a circular ring structure, and the inner hole diameter of the retreat layer (7) is larger than the outer diameter of the casting cavity (5).

2. According to claim 1, a technology for casting a large-scale I-shaped structure workpiece of a mining mill using a foam yielding layer is characterized by: The pouring system comprises a gate (1), a sprue (2), a runner (3) and an ingode (4); the lower end of the gate (1) is connected to the sprue (2), and the lower end of the sprue (2) is connected to the runner (3); the ingode (4) is located below the casting cavity (5), the upper end of the ingode (4) is connected to the bottom of the casting cavity (5), and the lower end of the ingode (4) is connected to the runner (3).

3. According to claim 1, a technology for casting a large-scale I-shaped structure workpiece of a mining mill using a foam yielding layer is characterized by: The sand core (9) is arranged on a sand core seat at the center bottom of the casting cavity (5), and a vent hole is arranged in the middle of the sand core (9).

4. According to claim 1, a technology for casting a large-scale I-shaped structure workpiece of a mining mill using a foam yielding layer is characterized by: A parting line is provided at the upper end of the casting cavity (5), and the parting line divides the casting cavity (5) into an upper box 11 and a lower box 12; positioning holes 8 are provided on the contact surfaces of the upper box 11 and the lower box 12, and the upper and lower positioning holes 8 correspond to each other.

5. According to claim 1, the technology of using a foam yield layer to cast a large-scale I-shaped structure workpiece of a mining mill is characterized by: The riser (10) is an annular structure, the outer diameter of the riser (10) is larger than the outer diameter of the casting cavity (5), and the inner diameter of the riser (10) is smaller than the inner diameter of the casting cavity (5).

6. The technology of using a foam yielding layer to cast a large-scale I-shaped structure workpiece of a mining mill according to claim 1 is characterized by: The thickness of the retreat layer (7) is not less than 30 mm.

7. The technology of using a foam yielding layer to cast a large-scale I-shaped structure workpiece of a mining mill according to claim 1 is characterized by: The radius difference between the inner hole of the retreat layer (7) and the outer diameter of the casting cavity (5) is amm, 50<a<70.

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