CN109175235B

CN109175235B - Fixing method of mud core, box body and casting method of multi-cavity channel casting

Info

Publication number: CN109175235B
Application number: CN201810748347.2A
Authority: CN
Inventors: 王永红
Original assignee: Shannxi Diesel Engine Heavy Industry Co Ltd
Current assignee: Shannxi Diesel Engine Heavy Industry Co Ltd
Priority date: 2018-07-10
Filing date: 2018-07-10
Publication date: 2021-10-12
Anticipated expiration: 2038-07-10
Also published as: CN109175235A

Abstract

The invention discloses a method for fixing a mud core and a method for casting a box body and a multi-cavity casting, which can realize a method for quickly fixing mud cores and casting molds of different dimensions, mud cores and casting molds; fixing an isolated mud core and a multi-stage mud core; the connecting mode of various fixing tools can be selected, such as a part embedding method, a drilling method and the like. The invention avoids the problems of floating core and fire running caused by the mode of fixing the mud core by using the core support, avoids the problem of leakage caused by using the core support, avoids the repair of the leakage of the core support part and reduces the casting cost; the problems of size deviation and even skin penetration caused by a mud core laminating and fixing mode are solved, the size precision of the complex casting is improved, and the sealing performance of the complex casting is improved; the method provides a remedy measure in the box matching process for the casting fire running problem caused by poor adhesion of the sand box and the casting mold, reduces the possibility of casting fire running and scrapping, and saves the molding cost.

Description

Fixing method of mud core, box body and casting method of multi-cavity channel casting

Technical Field

The invention relates to the technical field of casting preparation, in particular to a method for fixing a mud core, a box body and a casting method for multi-cavity castings.

Background

The equipment industry level of a country is synchronous with the whole industrial state, and the proportion of the casting in all equipment part blanks is more than the sum of other blanks such as forging, welding and the like. The casting has more than two thousand years of production and development history in China, and from the casting of early colored parts such as casting tripods and the like and the casting of simple iron castings such as ploughshares and the like to the casting of various black and colored parts which are applied to the fields of shipbuilding, aviation, weaponry, nuclear industry and the like in modern and various ways, although the casting process, the method, the diversity of materials and the comprehensive performance indexes of the castings are greatly enriched and improved, the casting mode and the mud core fixing mode for forming the castings have no great change all the time for hundreds of years, and the casting production is still carried out by the mode of locking boxes and pressing cores.

In recent two-thirty years, with the development of chemical industry, the traditional casting production mode of wet type or dry type clay sand using bentonite as a binder is gradually replaced by the mode of molding and core-making production of resin sand (phenolic resin, furan resin and the like) using various organic chemical binders as additives. The most widely applied cold box resin sand casting production mode is introduced into China from the west at the end of the last century, and the cold box resin sand casting production mode is rapidly popularized and popularized in the domestic casting industry by the advantages of high core strength, uniform strength distribution, convenience in operation, high efficiency and the like, and more than 80% of black castings in China are produced by adopting a resin sand molding core making mode.

The upper and lower molds are generally locked by clips or bolts in the existing cold core box resin sand casting process, and are fastened together by the adhesive force of the sand box and the resin sand of the upper and lower molds. The mud core is generally provided with a core head, and the core head or the mud core is fixed at a preset position of a lower mold through the upper mold, so that a casting with the inner and outer shapes and sizes meeting the requirements is obtained.

For more complex castings (such as diesel engine bodies, cylinder covers, box bodies, shells and the like) with the internal and external shapes and sizes formed by mud cores, the external mud cores are generally sleeved into sand boxes and then filled with resin sand during molding, and the external mud cores are fixed after the resin sand is hardened. The internal mud core is generally fixed in a layer-by-layer laminating mode. For some mud cores coated by multifaceted iron liquid, the mud cores and the casting mold are adhered together by using an adhesive, or the mud cores are fixed by embedding a metal core support.

Most of the traditional core fixing modes can meet production requirements, but for some castings with high dimensional precision requirements, pressure or leakage requirements, special requirements for thick and large parts and the like, the traditional core fixing modes are more and more exposed, and are insufficient and inconvenient. The castings with special requirements produced by the traditional fixing mode often have the quality problems of leakage, size out-of-tolerance, poor density and the like, and the defects of casting penetration, fire running and the like also often occur in the production practice.

The traditional core fixing mode often cannot meet the normal production requirements for some special castings, and the rejection rate is often higher.

1. Multi-surface closed box casting

As shown in figure 1, a certain thick large box body is a box body casting with five closed surfaces and one open surface, and the axle seat part of the casting needs to bear alternating stress and has higher requirement. As a certain lubricating oil medium needs to be stored in the box body, and the sealing requirement is met, the casting needs to be subjected to a kerosene seepage test, and the leakage cannot occur after the inside of the casting is soaked for 12 hours. In the process, the shaft seat faces downwards, the appearance is formed by a lower model, and the inner cavity is formed by two mud cores. Because five surfaces of the mud core forming the inner cavity are coated by the molten iron, in order to prevent the mud core from floating upward under the action of buoyancy, a certain number of chaplets are generally placed between the upper surface of the mud core and an upper mold to fix the mud core (as shown in fig. 2). In the production process, the situation that the chaplet is melted by the molten iron, the chaplet shifts in position and the mud core floats upwards often occurs, so that the castings are scrapped. Sometimes, the condition that the casting is scrapped because the gap between the upper mold and the lower mold cannot be locked after the mold is closed due to the size of the core support being out of tolerance is caused. When the produced castings are subjected to a kerosene seepage test in subsequent inspection, most of the kerosene seeps out of the core support part, so that great manpower and material resources are consumed for repairing the seeped part.

2. Multi-cavity channel casting with complex shape

FIG. 3 shows a diesel engine bracket part of a certain type, which is large in size (the outline size is 2500 x 1200 x 1000 mm), irregular in external shape, multiple in internal cavity channels (7 cavities, 2 two-way pipelines, 1 three-way pipeline and 1 four-way pipeline are arranged inside), large in casting wall thickness difference, 10mm in minimum wall thickness and 210mm in maximum wall thickness. Because the support bears the pressure of 1.5MW, the requirements on the sealing property and the compactness of the casting are high, and ultrasonic detection and hydrostatic test are required.

As shown in fig. 4, seven cavities and external shapes inside the casting are technically subjected to mud core division, and the main internal and external shapes of the casting are formed through the mud core. The casting mud cores are divided into seven layers, and the number of the mud cores is 22. During production, the mud cores of the layers are fixed in a laminating mode, namely the mud core of the second layer is pressed on the mud core of the first layer, the mud core of the third layer is pressed on the mud core of the second layer, and the rest is done in turn, and the mud core of the uppermost layer and the isolated mud core are fixed through a core support.

The support produced by the laminated mud core fixing mode has more problems, and especially has larger shape and size deviation. After part of products are poured, the out-of-tolerance size is serious, so that the castings are worn through the skin and discarded, as shown in figure 5. And part of the castings are leaked in the subsequent hydrostatic test, and the pressure of the oil duct cavity is reduced quickly in the hydrostatic test. Because the leakage part is mostly positioned between the inner cavity and the cavity, the leakage position can not be checked visually generally, and the leakage part can not be repaired, thereby causing casting scrapping.

Therefore, it is necessary to provide a new method for fixing mud cores, a box body and a casting method for multi-cavity castings, which solve the above-mentioned drawbacks of the prior art.

Disclosure of Invention

In order to solve the technical problems, the invention provides a method for fixing a mud core, a box body and a casting method of multi-cavity castings.

The invention provides a method for fixing mud cores and a method for casting a box body and multi-cavity channel castings, which adopt the following technical scheme:

a method for fixing mud cores comprises the steps of placing embedded channels in positions corresponding to the mud cores, and connecting and fastening embedded parts in a casting mold and the mud cores by using pull rods during box matching.

A casting method of a box casting comprises the following steps:

s1: embedding the embedded part 2;

placing an embedded part 2 on the model 1 at a position 150mm away from the edge, and placing the embedded part 2 in the center of the bearing seat;

s2: placing the sand box 3;

reversely buckling a sand box 3 on the model 1, filling resin sand 4, compacting, hardening for 1-2 hours, stripping, shaping, brushing paint 5 for later use, and thus obtaining a casting mold A;

s3: manufacturing a No. 1 sand core and a No. 2 sand core, and placing the sand cores into the pre-buried channel;

2 step-shaped pre-buried channels with the diameter of 60-80 phi are placed in the position 150mm away from the edge in the

first core box

6, 1 pre-buried channel with the diameter of 60-80 phi is arranged in the center of a bearing seat of the No. 2 core box 8, and resin sand 4 is filled in the pre-buried channels; after hardening for 1-2 hours, stripping, trimming the core and brushing a coating 5 for later use;

s4: preparing a box;

placing the No. 1 sand core and the No. 2 sand core for 12-24 hours and then carrying out box matching operation;

s5: connecting and fastening;

fixedly connecting the connecting rods 12 with the embedded parts 2 in the casting A respectively from top to bottom through the reserved channels;

s6: molding;

filling resin sand 4 into the pre-buried channel to the step, placing a gasket 14, and locking by using double nuts 15; the nut is covered with a heat insulation material 16 and then filled and leveled by resin sand 4; coating refractory zircon powder coating 113 times after the resin sand is hardened for 10-20 minutes, controlling the baume degree of the first time to Be 60-65 degrees Be, controlling the baume degree of the second time to Be 70-75 degrees Be, and controlling the baume degree of the third time to Be 40-60 degrees Be; then standing for 4-6 hr.

Preferably, in S1, the depth of the embedded part 2 in the casting mold A is more than 100 mm.

Preferably, in S3, the embedded channel is a hollow pipe 7.

Preferably, in S4, the box matching step includes:

A. placing the casting mold A in a box preparation field, checking whether the casting mold is horizontal by using a level ruler, and cleaning a core making and mud core;

B. putting a No. 2 mud core into the casting mold A, checking the size and the position of the mud core, and cleaning a cavity;

C. and putting a No. 1 mud core on the No. 2 mud core in the casting mold A, and checking the size and the position of the No. 1 mud core.

Preferably, in S5, the connecting rod 12 passes through the hollow pipe 7, which is a reserved passage reserved in the mud core 1 and the mud core 2, respectively, from top to bottom, and is fixedly connected with the embedded part 2 in the casting mold a.

Preferably, the fixed connection mode is a mode of hook and hook or a mode of screw and nut or a mode of T-shaped rod and T-shaped groove.

A casting method of a multi-cavity casting comprises the following steps:

s1: making an upper mold and a lower mold of a casting mold;

manufacturing a casting mold: after checking the shape and the size of the mold, cleaning the surface of the mold, and brushing the mold release agent for three times at intervals of 5-10 minutes; putting the release agent into a sand box at a preset position after drying; filling resin sand on the surface of the model and compacting;

after the casting mold is hardened, 4 inches of iron nails are used for testing the hardness of the casting mold, and when the iron nails cannot be inserted into the periphery and the top surface of the sand box, the mold is pulled up; checking the shape and the size of the cast after stripping, and performing surface reforming after the shape and the size are correct; cleaning the surface of the casting mold, brushing a coating, wherein the coating is an alcohol-based zircon powder coating, brushing for three times, controlling the baume degree for the first time to Be 60-65 DEG Be, controlling the baume degree for the second time to Be 70-75 DEG Be, and controlling the baume degree for the third time to Be 40-60 DEG Be;

casting under the mold: the operation is the same as above;

s2: manufacturing mud cores;

filling resin sand and a core bone in the core box in sequence, compacting, and stripping and repairing the core after hardening; coating the paint, and the operation is the same as S1; drying the mud core in a drying kiln at the drying temperature of 160-220 ℃ for 1-3 hours;

s3: box preparation operation;

drying the mud cores, placing the casting mold for 24 hours, and then performing box matching operation; the casting mold is placed in a working site, a level meter is used for checking in different directions, and the parting surface of the casting mold is adjusted to a horizontal position; checking that the casting mold and each mud core working area have no paint accumulation and the head part of the core has no unevenness;

then setting a core, drilling embedded channels on the mud core to be fixed in sequence, sucking out sand grains in the holes, then knocking in the embedded parts, and fixedly connecting the embedded parts with the mud core set;

s4: assembling the box;

checking the position and the size of each mud core of the upper and lower molds, and closing the mold after the mold cavity is clean;

s5: drying the casting mold;

and blowing hot air to the casting mold through the sprue, wherein the temperature of the hot air is controlled at 220 ℃ at 160-.

In S3, the sequence of the lower core is:

(a) putting No. 1 mud cores and No. 4 mud cores at the bottommost part of the lower casting mold, and checking that the size and the position of the mud cores are accurate;

(b) Sequentially placing four mud cores of No. 2 mud core, No. 3 mud core, No. 7 mud core and No. 8 mud core from bottom to top on the left side;

(c) sequentially putting two layers of mud cores of No. 5 mud core and No. 6 mud core from bottom to top on the right side;

(d) the 13 # mud core and the 10 # mud core are sequentially arranged from outside to inside on the third layer on the left side;

(e) the No. 14 mud core, the No. 11 mud core and the No. 12 mud core are sequentially arranged from outside to inside in the third layer on the right side;

(f) putting a No. 15 mud core, a No. 16 mud core and a No. 19 mud core into the middle part;

(g) no. 20 is placed at the uppermost layer of the right side;

(h) no. 19 is placed at the uppermost layer of the middle part;

(i) and putting No. 21 mud cores and No. 22 mud cores into the upper casting mold.

In S3, the step of fixing the mud core comprises the following steps:

(1) fixing the mud core group 1: the mud core group 1 comprises a No. 2 mud core, a No. 3 mud core and a No. 7 mud core;

after the core setting step (b), fixing the No. 2 mud core, the No. 3 mud core and the No. 7 mud core; the method comprises the following specific steps:

after the sizes and the positions of the No. 2 mud core, the No. 3 mud core and the No. 7 mud core are checked to be accurate, 1 phi 30/phi 12 step hole is drilled in the core 7, and the hole sequentially penetrates through the No. 7 mud core, the No. 3 mud core and the No. 2 mud core from top to bottom and enters a lower casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

knocking the component I into a phi 12 hole, sequentially putting a phi 12 gasket, a phi 24 gasket and an M12 nut, then locking, putting a refractory material on the nut, filling resin sand, hardening for 10-20 minutes, and then coating a refractory coating;

(2) fixing the mud core group 2: the mud core group 2 comprises a 19 # mud core, a 13 # mud core and a 10 # mud core;

fixing the No. 19 mud core, the No. 13 mud core and the No. 10 mud core after the core setting step (e); the method comprises the following specific steps:

after checking the sizes and the positions of the No. 19 mud core, the No. 13 mud core and the No. 10 mud core are accurate, drilling 1 phi 30/phi 12 step holes on the No. 19 mud core, the No. 13 mud core and the No. 10 mud core in sequence, and enabling the holes to pass through the No. 19 mud core, the No. 13 mud core and the No. 10 mud core and enter a lower casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

knocking the component II into a phi 12 hole, sequentially putting a phi 12 gasket, a phi 24 gasket and an M12 nut, locking, putting a refractory material, filling resin sand, hardening for 10-20 minutes, and then coating a refractory coating;

(3) fixing the mud core group 3: the mud core group 3 comprises a No. 14 mud core, a No. 12 mud core and a No. 6 mud core;

fixing No. 14 mud cores, No. 12 mud cores and No. 6 mud cores after the core setting step (e); the method comprises the following specific steps:

after checking the sizes and the positions of No. 14 mud cores, No. 12 mud cores and No. 6 mud cores are accurate, drilling 1 phi 30/phi 12 step holes in the No. 14 mud cores, wherein the holes pass through the No. 14 mud cores, the No. 12 mud cores and the No. 6 mud cores in sequence and enter a lower casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

knocking the component III into a phi 12 hole, sequentially putting a phi 12 gasket, a phi 24 gasket and an M12 nut, locking, putting a refractory material, filling resin sand, hardening for 10-20 minutes, and then coating a refractory coating;

(4) fixing the mud core group 4: the mud core group 4 comprises a middle mud core No. 15 mud core, a middle mud core No. 4 mud core and a middle mud core No. 1 mud core;

after the core setting step (h),' fixing No. 15 mud cores, No. 4 mud cores and No. 1 mud cores; the method comprises the following specific steps:

after checking the sizes and the positions of the No. 15 mud core, the No. 4 mud core and the No. 1 mud core are accurate, drilling 1 phi 30/phi 12 step holes in the No. 15 mud core, the No. 4 mud core and the No. 1 mud core in sequence, and enabling the holes to penetrate through the No. 15 mud core, the No. 4 mud core and the No. 1 mud core and enter a lower casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

knocking the component IV into a phi 12 hole, sequentially putting a phi 12 gasket, a phi 24 gasket and an M12 nut, locking, putting a refractory material, filling resin sand, hardening for 10-20 minutes, and then coating a refractory coating;

(5) fixing the upper mud core:

after checking the sizes and the positions of the No. 21 mud core and the No. 22 mud core are accurate, respectively drilling 1 phi 30/phi 12 step holes on the No. 21 mud core and the No. 22 mud core, and enabling the holes to penetrate through the No. 21 mud core and the No. 22 mud core and enter an upper casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

and knocking the component V into a phi 12 hole respectively, sequentially putting a phi 12 gasket, a phi 24 gasket and an M12 nut, locking, putting a refractory material, filling resin sand, hardening for 10-20 minutes, and then coating a refractory coating.

Compared with the related art, the invention has the following technical effects:

1. the invention avoids the problems of floating core and fire escaping caused by the mode of fixing the mud core by using the core support, avoids the problem of leakage caused by using the core support, avoids the repair of the leakage of the core support part and reduces the casting cost.

2. The invention aims to solve the problems of size deviation and even skin penetration caused by a mud core laminating and fixing mode, improve the size precision of a complex casting and improve the sealing performance of the complex casting.

3. The invention provides a remedy measure for the casting fire running problem caused by poor adhesion between the sand box and the casting mould in the box matching process, reduces the possibility of casting fire running and scrapping, and also saves the molding cost.

4. The invention locks or extrudes the specific part of the casting, can fully utilize the self-feeding property of the nodular cast iron and improve the compactness of the casting. Compared with the common casting passive feeding, the feeding deficiency forming shrinkage porosity defect provides a solution.

5. The invention can realize multi-dimensional barrier-free locking in a box-free modeling mode such as core assembling modeling, core stacking modeling and the like, and is convenient and quick.

6. The invention can ensure the position and dimensional accuracy of the isolated mud core, the cantilever mud core and the slender mud core in the processes of box preparation and pouring by adopting the fixing mode.

Drawings

FIG. 1 is a schematic view of a prior art multi-faced closed box casting;

FIG. 2 is a schematic view showing the connection relationship between mud cores and chaplets of a box casting with closed multiple surfaces in the prior art;

FIG. 3 illustrates a portion of a diesel engine mount of the prior art;

FIG. 4 is a cross-sectional view of a multi-channel casting of the prior art;

FIG. 5 is a schematic view of a multi-channel casting according to the prior art;

FIGS. 6 to 14 are schematic views illustrating steps of a casting method of a box casting according to the present invention;

FIGS. 15 to 16 are schematic views illustrating steps of a method of casting a multi-chamber cast object according to the present invention.

Detailed Description

The invention will be further explained with reference to the drawings and the embodiments.

The invention relates to a method for quickly fixing mud cores and casting molds, mud cores and casting molds with different dimensions, which are key points of the invention. And secondly, fixing the isolated mud core and the multistage mud core. And thirdly, the connection mode of various fixed tools can be selected, such as a part embedding method, a drilling method and the like.

According to the method for fixing the mud cores, the embedded channels are arranged in the corresponding positions of the mud cores, and embedded parts in a casting mold are connected and fastened with the mud cores through the pull rods during box matching.

The casting method of the box body casting comprises the following steps:

s1: embedding the embedded part 2;

placing an embedded part 2 on the model 1 at a position 150mm away from the edge, and placing the embedded part 2 in the center of the bearing seat; as shown in fig. 6;

s2: placing the sand box 3;

reversely buckling a sand box 3 on the model 1, filling resin sand 4, compacting, hardening for 1-2 hours, stripping, shaping, brushing paint 5 for later use, and thus obtaining a casting mold A; as shown in fig. 7;

as shown in the figures 8-11, 2 step-shaped pre-buried channels with phi 60-phi 80 are arranged in the position 150mm away from the edge in the

first core box

6, and 1 pre-buried channel with phi 60-phi 80 is arranged in the center of a bearing seat of the No. 2 core box 8, and resin sand 4 is filled in the pre-buried channels; after hardening for 1-2 hours, stripping, trimming the core and brushing a coating 5 for later use;

s4: preparing a box;

as shown in fig. 12-13, the No. 1 sand core and the No. 2 sand core are placed for 12-24 hours to carry out box matching operation;

s5: connecting and fastening;

s6: molding;

as shown in fig. 14, resin sand 4 is filled into the pre-buried channel to the step, and a gasket 14 is placed and then locked by a double nut 15; the nut is covered with a heat insulation material 16 and then filled and leveled by resin sand 4; coating refractory zircon powder coating 113 times after the resin sand is hardened for 10-20 minutes, controlling the baume degree of the first time to Be 60-65 degrees Be, controlling the baume degree of the second time to Be 70-75 degrees Be, and controlling the baume degree of the third time to Be 40-60 degrees Be; then standing for 4-6 hr.

Preferably, in S3, the embedded channel is a hollow pipe 7.

Preferably, in S4, the box matching step includes:

Meanwhile, the casting method of the multi-cavity channel casting comprises the following steps:

s1: making an upper mold and a lower mold of a casting mold;

as shown in fig. 15 to 16, a mold upper mold was prepared: after checking the shape and the size of the mold, cleaning the surface of the mold, and brushing the mold release agent for three times at intervals of 5-10 minutes; putting the release agent into a sand box at a preset position after drying; filling resin sand on the surface of the model and compacting;

casting under the mold: the operation is the same as above;

s2: manufacturing mud cores;

s3: box preparation operation;

s4: assembling the box;

s5: drying the casting mold;

In S3, the sequence of the lower core is:

(g) no. 20 is placed at the uppermost layer of the right side;

(h) no. 19 is placed at the uppermost layer of the middle part;

In S3, the step of fixing the mud core comprises the following steps:

sucking out sand grains in the hole;

(5) fixing the upper mud core:

sucking out sand grains in the hole;

When the cast casting is cast, the casting molding steps are as follows:

smelting pig iron, scrap steel, carburant and the like in an intermediate frequency furnace, standing at 1490-1510 ℃, spheroidizing and inoculating for the first time at 1450-1480 ℃, inoculating along with molten iron twice when discharging 2/3, pouring the molten iron into a pouring cup containing instant inoculant for inoculating for the third time, starting an iron liquid control gate when the temperature of the iron liquid in the pouring cup is 1370-1400 ℃, and enabling the iron liquid to enter a casting mold.

The nodulizer is controlled to be 1.1-1.4% of the weight of the molten iron. The total amount of the inoculant is controlled to be 0.8-1.2% of the weight of the molten iron, wherein 0.4-0.5% of the inoculant is a primary inoculant which reacts with a nodulizer during ladle charging, 0.3-0.4% of a secondary inoculant which flows along with the molten iron, and 0.1-0.3% of an instant inoculant which is placed in a pouring cup.

The nodulizer adopted in the nodulizing treatment is ADLLOY6RE type rare earth magnesium alloy with the granularity of 5-20 mm, the primary inoculant and the secondary inoculant are a mixture of 75SiFe and Incollin380 with the proportion of half respectively, and the granularity is 3-10 mm and 15-30 mm respectively. The tertiary inoculant is Incollin380 with the granularity of 0.5-2.0 mm.

The casting adopts a pouring mode of intermediate injection, the speed of the liquid surface is 21mm/s, the pouring time is 75-90 seconds, and the pouring weight is 3.2 tons.

Demonstration example:

the invention is used for locking mud cores of air cavities of certain diesel engine bodies, as shown in figure 16. The machine body used for implementing the invention is made of nodular cast iron with the material brand of QT400-15, and the smelting ingredients are controlled as shown in Table 1. The control of the main chemical components in the smelting process in the inventive example is shown in Table 2. The parameters of pouring temperature, time and the like in the invention examples are controlled as shown in Table 3.

The comparison of the detection result and the standard parameters of the main assessment indexes of the invention can be known as follows: the QT400-15 of the different components all meet the performance index requirement of the diesel engine body. Meanwhile, the cast engine body has no leakage condition after a hydraulic test of 1.0MPa for 60 minutes, so that the diesel engine body is feasible by adopting the air cavity mud core locking and smelting and pouring process.

Table 1: smelting burden control

Table 2: smelting chemical composition

Table 3: pouring parameter control

The above description is only a preferred embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by using the contents of the present specification and the accompanying drawings, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.

Claims

1. A casting method of a multi-cavity casting is characterized by comprising the following steps:

s1: making an upper mold and a lower mold of a casting mold;

after the casting mold is hardened, 4 inches of iron nails are used for testing the hardness of the casting mold, and when the iron nails cannot be inserted into the periphery and the top surface of the sand box, the mold is pulled up; checking the shape and size of the stripped casting mould, and finishing the surface of the casting mould after the shape and size are correct; cleaning the surface of the casting mold, brushing a coating, wherein the coating is an alcohol-based zircon powder coating, brushing for three times, controlling the baume degree for the first time to Be 60-65 DEG Be, controlling the baume degree for the second time to Be 70-75 DEG Be, and controlling the baume degree for the third time to Be 40-60 DEG Be;

casting under the mold: the operation is the same as above;

s2: manufacturing mud cores;

s3: box preparation operation;

s4: assembling the box;

s5: drying the casting mold;

blowing hot air to the casting mold through the sprue, wherein the temperature of the hot air is controlled at 220 ℃ in 160-8 hours, and the temperature measurement position is 200mm below the air outlet farthest from the sprue;

in S3, the sequence of the lower core is:

(a) placing No. 1 mud cores and No. 4 mud cores at the bottommost part of the lower casting mold, and checking that the size and the position of the mud cores are accurate;

(d) the No. 13 mud core and the No. 10 mud core are sequentially arranged from outside to inside on the third layer on the left side;

(e) the No. 14 mud core, the No. 11 mud core and the No. 12 mud core are sequentially arranged from outside to inside on the third layer on the right side;

(g) no. 20 mud cores are placed on the uppermost layer of the right side;

(h) a 19 # mud core is put into the uppermost layer of the middle part;

(i) putting No. 21 and No. 22 mud cores into the upper casting mold;

in S3, the step of fixing the mud core comprises the following steps:

sucking out sand grains in the hole;

after the sizes and the positions of the No. 19 mud core, the No. 13 mud core and the No. 10 mud core are checked to be accurate, 1 phi 30/phi 12 step hole is drilled in the No. 19 mud core, and the hole sequentially penetrates through the No. 19 mud core, the No. 13 mud core and the No. 10 mud core and enters a lower casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

after the sizes and the positions of the No. 14 mud core, the No. 12 mud core and the No. 6 mud core are checked to be accurate, 1 phi 30/phi 12 step hole is drilled in the No. 14 mud core, and the hole sequentially penetrates through the No. 14 mud core, the No. 12 mud core and the No. 6 mud core and enters a lower casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

after the core setting step (h), fixing the No. 15 mud core, the No. 4 mud core and the No. 1 mud core; the method comprises the following specific steps:

after the sizes and the positions of the No. 15 mud core, the No. 4 mud core and the No. 1 mud core are checked to be accurate, 1 phi 30/phi 12 step hole is drilled in the No. 15 mud core, and the hole sequentially penetrates through the No. 15 mud core, the No. 4 mud core and the No. 1 mud core and enters a lower casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;

(5) fixing the upper mud core:

after the sizes and the positions of the No. 21 mud core and the No. 22 mud core are checked to be accurate, 1 phi 30/phi 12 step hole is drilled in the No. 21 mud core and the No. 22 mud core respectively, and the holes penetrate through the No. 21 mud core and the No. 22 mud core respectively and enter an upper casting mold; the step depth of the step hole is 60mm, and the depth of the step hole entering the lower casting mold is 80-100 mm;

sucking out sand grains in the hole;