CN112620583A

CN112620583A - Manufacturing method of long and narrow hole groove on thin wall of ductile iron casting

Info

Publication number: CN112620583A
Application number: CN202011537385.7A
Authority: CN
Inventors: 柏栋; 莫国先; 张词; 唐仁芬; 欧夏天
Original assignee: Chongqing Jiangjin Turbo & Charger Machinery Co ltd
Current assignee: Chongqing Jiangjin Turbo & Charger Machinery Co ltd
Priority date: 2020-12-23
Filing date: 2020-12-23
Publication date: 2021-04-09

Abstract

The invention reduces the operation difficulty of molding and core making, solves the defects of casting perforation, sand inclusion and the like caused by unqualified sand mold performance, and discloses a method for manufacturing a long and narrow hole groove on a ductile iron casting thin wall. A manufacturing method of a long and narrow hole groove on a ductile iron casting thin wall comprises the following steps: s1, independently manufacturing a sand core with a long and narrow hole groove; s2, after the sand core is solidified and formed, performing surface treatment on the sand core; s3, coating a layer of coating paste on the surface of the sand core for filling the gap between the sand and the gravel on the surface of the sand core; s4, after the coating paste is dried, polishing the surface of the sand core, then smearing a layer of zircon coating on the surface of the sand core, and drying; s5, winding glass fiber cloth on the part of the sand core corresponding to the casting long and narrow hole groove; s6, coating a refractory coating on the surface of the sand core; and S7, casting a long narrow hole groove on the thin wall of the ductile iron casting, and casting the ductile iron casting at the same time.

Description

Manufacturing method of long and narrow hole groove on thin wall of ductile iron casting

Technical Field

The invention relates to the technical field of sand casting, in particular to a method for manufacturing a long and narrow hole groove on a ductile iron casting thin wall.

Background

In the case of heavy machinery, there are often grooves or holes that are cast, and these grooves or holes are often difficult to machine (very expensive) or cannot be machined at all. But have some grooves and holes such as: thin wall thickness, narrow width, large depth, and small hole diameter, such castings generally require that no chaplet be used, such as shown in fig. 1. The casting difficulty is very high under the condition of traditional sand casting, and the following points are mainly included: firstly, manual sand filling is inconvenient during core making, and the molding difficulty is high; secondly, the sand mold has insufficient strength and is easy to break under the impact of molten iron; and thirdly, because the sand mould is thin, molten iron is easy to permeate and corrode, so that sand inclusion is produced, the cleaning cost is high, the efficiency is low, and a casting is scrapped when the cleaning cost is serious.

Disclosure of Invention

The invention aims to reduce the difficulty of molding and core making operation, overcome the defects of casting perforation, sand inclusion and the like caused by unqualified sand mold performance, and provide a method for manufacturing a long and narrow hole groove on a ductile iron casting thin wall.

The purpose of the invention is realized as follows:

a manufacturing method of a long and narrow hole groove on a ductile iron casting thin wall comprises the following steps:

s1, independently manufacturing a sand core with a long and narrow hole groove;

s2, after the sand core is solidified and formed, performing surface treatment on the sand core;

s3, coating a layer of coating paste on the surface of the sand core for filling the gap between the sand and the gravel on the surface of the sand core;

s4, after the coating paste is dried, polishing the surface of the sand core, then smearing a layer of zircon coating on the surface of the sand core, and drying;

s5, winding glass fiber cloth on the part of the sand core corresponding to the casting long and narrow hole groove;

s6, coating a fireproof coating on the surface of the wound glass fiber cloth; the heat resistance of the alloy is strengthened;

and S7, casting a long narrow hole groove on the thin wall of the ductile iron casting, and casting the ductile iron casting at the same time.

Preferably, the sand core adopts a cantilever core structure, the thickness of a core head of the sand core is 2-5 times of that of the long and narrow hole groove, and the transition section of the sand core is in slope transition.

Preferably, the core bone of the sand core is fishbone-shaped.

Preferably, the sand core is formed by tightly pounding the sand core with the sand-free ore, and the core bone of the sand core is completely immersed in the sand-free ore.

Preferably, in step S5, a layer of glass fiber cloth is wound on the sand core corresponding to the slot of the casting. And the sand core falls off together after casting is finished.

Preferably, in step S6, two layers of refractory coatings are applied to the surface of the sand core, and after the previous layer of refractory coating is completely dried, the next layer of refractory coating is applied and dried.

Due to the adoption of the technical scheme, the invention has the following beneficial effects:

on the basis of the traditional process scheme, process innovation is carried out from three aspects according to the casting structure and by combining actual experience and production modeling conditions.

1. The grooves and the hole parts are cast into cores independently, so that other core box structures can be effectively simplified; the sand filling mode is more and more flexible, and the core making difficulty is reduced.

2. The sand core is made of the sand with better heat transfer performance and higher strength.

3. The parts of the mud core corresponding to the grooves and the holes are wound with heat-resistant glass ribbons, and the heat-resistant glass ribbons have strong heat resistance (about 1000 ℃) and heat insulation property, so that sand sticking of castings can be effectively solved; meanwhile, the coating has strong permeability, can be well compatible with various resins, has smooth surface and has little influence on the appearance quality of the casting.

Drawings

FIG. 1 is a schematic perspective view of a ductile iron casting;

FIG. 2 is a schematic structural view of a ductile iron casting;

FIG. 3 is a schematic view of the structure of the slot;

FIG. 4 is a schematic diagram of the structure of a sand core;

fig. 5 is a schematic structural view of a core bar.

Detailed Description

A method for manufacturing a slot on a thin wall of a ductile iron casting, the casting in figure 2 is provided with a slot, and the cost is high and the efficiency is low by using a processing means. It has a width of 100mm in the circumferential direction, and the remaining dimensions are as shown in fig. 3.

Where the invention is solely cored, as shown in fig. 4. Considering that the core is a cantilever core, the core head is increased and deepened intentionally, and the transition section of the core is thickened. The fishbone-shaped core bone is prepared in advance for standby. (shown in FIG. 5)

The operation main steps are as follows:

1. manufacturing a loam core by using the sand, pounding a sand mold by a worker until the core bone is not exposed outside, and waiting for solidification of the sand mold;

2. after curing, carrying out surface treatment (polishing, repairing and the like) on the sand core; then coating a layer of coating paste capable of filling the gap between the gravels on the surface; and after the coating paste is dried, polishing the surface again, then brushing zircon coating with better heat resistance, and igniting and drying.

3. After baking and drying, a layer of glass fiber cloth is wound on the position, corresponding to the casting groove, of the sand core, and the sand core falls off together after casting is finished.

4. And brushing two layers of refractory coatings again, wherein the next layer is brushed after the previous layer is required to be completely dried.

5. The subsequent steps are carried out according to the traditional process.

Finally, it is noted that the above-mentioned preferred embodiments illustrate rather than limit the invention, and that, although the invention has been described in detail with reference to the above-mentioned preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as defined by the appended claims.

Claims

1. A manufacturing method of a long and narrow hole groove on a ductile iron casting thin wall is characterized by comprising the following steps:

s1, independently manufacturing a sand core with a long and narrow hole groove;

s6, coating a fireproof coating on the surface of the wound glass fiber cloth;

2. The method for manufacturing the slot on the thin wall of the ductile iron casting according to claim 1, wherein the slot is formed by: the sand core adopts a cantilever core structure, the thickness of a core head of the sand core is 2-5 times of that of the long and narrow hole groove, and the transition section of the sand core is in slope transition.

3. The method for manufacturing the slot on the thin wall of the ductile iron casting according to claim 1, wherein the slot is formed by: the core bone of the sand core is in a fishbone shape.

4. The method for manufacturing the slot on the thin wall of the ductile iron casting according to claim 1, wherein the slot is formed by: the sand core is formed by tightly pounding the sand core, and the core bone of the sand core is completely immersed in the sand core.

5. The method for manufacturing the slot on the thin wall of the ductile iron casting according to claim 1, wherein the slot is formed by: and in the step S5, a layer of glass fiber cloth is wound on the part of the sand core corresponding to the casting long narrow hole groove, and the glass fiber cloth falls off together with the sand core after casting is finished.

6. The method for manufacturing the slot on the thin wall of the ductile iron casting according to claim 1, wherein the slot is formed by: in the step S6, two layers of refractory coatings are applied to the surface of the sand core, and after the upper layer of refractory coating is completely dried, the next layer of refractory coating is applied and dried.