阅读说明：本技术 一种履带车辆综合传动系统动、定轮铸造方法 (Casting method for moving wheel and fixed wheel of comprehensive transmission system of tracked vehicle ) 是由 李爽 李宝栋 周建军 于大威 乔景忠 苏雅拉图 刘斌 王馨 刘亚楠 杨清 何立军 于 2020-06-12 设计创作，主要内容包括：本发明涉及一种履带车辆综合传动系统动、定轮铸造方法,步骤依次为：制作模具及芯盒-造型-制芯-合箱-浇注-打箱-抛丸-次清理-探伤-时效处理-转出。本发明采用砂型铸造覆膜砂组芯工艺,可以获得形状完整、表面光洁的铸件,从而保证铸件的表面质量和尺寸精度。设置冒口,在覆膜砂型芯中放置外冷铁对中间圆柱部位进行激冷,使铸件实现顺序凝固,保证冒口能够充分补缩热节处,有效地提高冒口的补缩效率,以获得健全的内部质量。在横浇道两处放置陶瓷过滤网,提高铁水的纯净度,浇注时充型平稳,防止产生卷气、夹砂、夹渣等铸造缺陷,同时改善铸铁机械性能和抗弯强度,达到表面硬度均匀化的目的。(The invention relates to a casting method of a moving wheel and a fixed wheel of a comprehensive transmission system of a tracked vehicle, which sequentially comprises the following steps: manufacturing a mold and a core box, modeling, making a core, assembling a box, pouring, boxing, shot blasting, secondary cleaning, detecting a flaw, performing aging treatment and transferring out. The invention adopts the sand mold casting precoated sand core assembly process, can obtain the casting with complete shape and smooth surface, thereby ensuring the surface quality and the dimensional accuracy of the casting. And a riser is arranged, and an external chill is placed in the precoated sand core to chill the middle cylindrical part, so that the casting is sequentially solidified, the riser can be ensured to fully feed a hot junction, and the feeding efficiency of the riser is effectively improved, so that the sound internal quality is obtained. The ceramic filter screens are arranged at two positions of the cross gate, so that the purity of molten iron is improved, the casting is stable during casting, casting defects such as entrainment, sand inclusion, slag inclusion and the like are prevented, the mechanical property and the bending strength of cast iron are improved, and the purpose of homogenizing the surface hardness is achieved.)

1. A casting method for a movable wheel and a fixed wheel of a comprehensive transmission system of a tracked vehicle is characterized by comprising the following steps:

s1, manufacturing a mold and a core box;

s2, modeling: a plurality of air hole needles are respectively fixed on the mould and the template, the top ends of the air hole needles are as high as the sand box, and the air vent holes are directly brought out by the model;

s3, core making: adopting precoated sand to manufacture a core at the inner cavity part of the blade formed by the core box, and placing an external chill on the core for chilling the middle cylindrical part of the casting;

s4, assembling the box;

s5, pouring: the pouring system enters two symmetrically arranged heat-insulating risers from two sides, and then enters the casting from the risers, and special ceramic filter screens are placed at two positions of the cross gate.

2. The casting method of the moving wheel and the fixed wheel of the comprehensive transmission system of the tracked vehicle as claimed in claim 1, wherein after pouring, the casting is carried out sequentially through box beating, shot blasting, secondary cleaning, flaw detection and aging treatment, and then the casting is carried out.

3. The method of claim 2, wherein the inspection of all blade portions is performed by magnetic particle inspection during inspection.

4. The casting method of the moving wheel and the fixed wheel of the comprehensive transmission system of the tracked vehicle as claimed in claim 2, wherein the aging treatment comprises the following steps: and performing stress relief annealing before the casting is rolled out.

5. The method of claim 1, wherein the mold is a metal mold.

6. The method for casting the moving wheel and the fixed wheel of the integrated transmission system of the tracked vehicle as claimed in claim 5, wherein the core box is of a detachable type.

7. The method of claim 5, wherein the mold comprises an upper box and a lower box; and the castings are all placed in the lower box of the mold, the blades of the castings face downwards, and a plurality of heat-insulating risers are arranged in the upper box of the mold corresponding to the flange plate hot junctions of the castings for feeding.

8. The method of claim 7, wherein in step S2, furan resin sand is used for molding.

9. The method of claim 7, wherein the core is inspected for acceptability, float sand is blown off before core setting, and core setting is inspected after core setting.

10. The method of claim 7, wherein sand floats from the surface of the mold cavity are purged prior to mold closing.

Technical Field

The invention belongs to the technical field of sand casting and forming, and particularly relates to a method for casting a movable wheel and a fixed wheel of a comprehensive transmission system of a tracked vehicle.

Background

The working environment of the comprehensive crawler transmission system is severe, the driving wheels and the fixed wheels are core parts of the comprehensive crawler transmission system which mainly bear loads, and the inner cavity of the comprehensive crawler transmission system is in direct contact with hydraulic oil. The moving wheel and the fixed wheel belong to thin-wall impeller castings, and the defects of high casting forming difficulty, easy generation of cold-insulated cracks and the like caused by dispersed hot spots and unsmooth feeding channels are overcome. Therefore, the moving wheel and the fixed wheel cannot meet the requirement of high reliability of the castings by using the traditional sand casting method.

The qualification rate of the casting in the traditional casting method is only about 45-60%, the rejection rate of the casting in the machining stage is high, the main problems are oil duct leakage, shrinkage porosity defects at multiple hot joints, casting deformation, secondary stress deformation, cold shut and crack problems at thin walls and the like, the rejection rate reaches 20%, and the repair rate reaches 30%. Meanwhile, because the processing period of the castings is long, many problems can be reflected in the finish machining stage, the loss is huge, the production progress of the products is severely restricted, and the castings become narrow openings for the production of the whole automobile.

Disclosure of Invention

The invention provides a casting method of a moving wheel and a fixed wheel of a comprehensive transmission system of a tracked vehicle, which solves the defects of the prior art.

In order to solve the technical problem, the invention provides a method for casting a movable wheel and a fixed wheel of a comprehensive transmission system of a tracked vehicle, which is characterized by comprising the following steps of:

s1, manufacturing a mold and a core box;

s2, modeling: a plurality of air hole needles are respectively fixed on the mould and the template, the top ends of the air hole needles are as high as the sand box, and the air vent holes are directly brought out by the model;

s3, core making: adopting precoated sand to manufacture a core at the inner cavity part of the blade formed by the core box, and placing an external chill on the core for chilling the middle cylindrical part of the casting;

s4, assembling the box;

s5, pouring: the pouring system enters two symmetrically arranged heat-insulating risers from two sides, and then enters the casting from the risers, and special ceramic filter screens are placed at two positions of the cross gate.

Has the advantages that: the invention adopts the sand casting precoated sand core assembly process, and can obtain a casting with complete shape and smooth surface due to the characteristics of high strength, good collapsibility, low gas generation, good sand adhesion resistance and the like of the precoated sand, thereby ensuring the surface quality and the dimensional accuracy of the casting. The riser is arranged at a position where thermal nodes are dispersed and shrinkage defects are easy to generate, and the external chill is placed in the precoated sand core to chill the middle cylindrical part, so that the casting is sequentially solidified, the riser can be ensured to fully supplement the thermal nodes, the feeding efficiency of the riser is effectively improved, and the sound internal quality is obtained. The pouring system firstly enters the risers symmetrically from two sides and then enters the casting through the risers to realize stable pouring, and ceramic filter screens are arranged at two positions of the cross gate, and have the characteristics of large specific surface area and thermal shock resistance. The casting method has the advantages that harmful impurities such as bubbles and nonmetallic inclusions in molten metal are filtered, the molten metal is purified, the purity of molten iron is improved, the casting is stable, new tiny vortexes cannot be generated when the molten metal passes through the uniform and consistent circular holes, the molten metal is converted from turbulent flow to laminar flow casting, accordingly, casting defects such as entrainment, sand inclusion and slag inclusion are prevented, the mechanical property and the bending strength of cast iron are improved, and the purpose of homogenizing the surface hardness is achieved.

Detailed Description

In order to make the objects, contents and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention is provided.

The invention provides a casting method of a movable wheel and a fixed wheel of a comprehensive transmission system of a tracked vehicle, which is characterized by comprising the following steps of:

s1, manufacturing a mold and a core box: manufacturing a metal mold and a core box according to a casting process diagram, wherein the core box adopts a detachable mode: the mould comprises an upper box and a lower box;

all castings are placed in a lower box of the mold, blades of a movable wheel or a fixed wheel face downwards, a plurality of 9/6K heat-insulating risers are arranged in the upper box of the mold and correspond to the positions of flange hot junctions of parts for feeding;

s2, modeling: the mould is molded by furan resin sand, a plurality of air hole needles are respectively fixed on the mould and the template, the top end of the air hole needles is as high as the sand box, and the vent holes are directly taken out by the molding, so that the air is exhausted and the defect of casting sand hole caused by floating sand generated when the sand mould vent holes are drilled is prevented.

S3, core making: adopting precoated sand with high strength and good collapsibility to manufacture a core at the inner cavity part of the blade formed by the core box, and placing external chill on the core for chilling the middle cylindrical part of the casting;

s4, mould assembling: and (4) checking whether the mold core is qualified or not, blowing clean floating sand before core setting, checking the core setting condition after core setting, and blowing clean floating sand on the surface of the mold cavity before mold closing.

S5, pouring: the pouring system enters two symmetrically arranged heat-insulating risers from two sides and then enters a casting from the risers, and special ceramic filter screens are placed at two positions of a cross gate so as to improve the purity of molten steel and realize stable mold filling during pouring.

S6, boxing, shot blasting, primary cleaning and flaw detection: and (4) carrying out magnetic powder inspection on all blade parts before the casting is rotated out.

S7, aging treatment: and performing stress relief annealing before the casting is rolled out.

And S8, rolling out.

The above description is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several modifications and variations can be made without departing from the technical principle of the present invention, and these modifications and variations should also be regarded as the protection scope of the present invention.