阅读说明：本技术 双流道涡轮增压器双流道砂芯组装工艺及双流道涡轮增压器壳体铸造工艺 (Double-flow-passage turbocharger double-flow-passage sand core assembly process and double-flow-passage turbocharger shell casting process ) 是由 张良楠 罗琪 朱瑞卿 于 2021-07-08 设计创作，主要内容包括：本发明提供一种双流道涡轮增压器双流道砂芯组装工艺及双流道涡轮增压器壳体铸造工艺,将第一流道砂芯和第二流道砂芯粘接形成组合砂芯；两个流道砂芯组合时在两个砂芯配合面之间留有配合间隙,同时将尺寸相当于两个砂芯之间配合间隙的易燃或易熔化的填充片放入配合间隙内；在室温下等待粘接剂固化后将组合砂芯进行浸涂操作；将浸涂后的组合砂芯在通风的条件下烘干制成双流道砂芯；烘干时,烘干温度高于填充片的燃点或熔点；将双流道砂芯与外模及其他砂芯进一步组合后进行浇铸；浇铸时,间隙空间的尺寸小于浇铸流体的毛细长度；脱模得到双流道涡轮增压器壳体成品。本申请避免分隔墙处浇铸充型过程排气不畅导致冷隔缺陷及飞边毛刺的问题。(The invention provides a double-runner sand core assembly process of a double-runner turbocharger and a casting process of a double-runner turbocharger shell, wherein a first runner sand core and a second runner sand core are bonded to form a combined sand core; when the two runner sand cores are combined, a fit clearance is reserved between the fit surfaces of the two sand cores, and meanwhile, a filling piece which is inflammable or easily melted and has the size equal to the fit clearance between the two sand cores is placed in the fit clearance; after the adhesive is cured at room temperature, dip-coating the combined sand core; drying the dip-coated combined sand core under the ventilation condition to prepare a double-runner sand core; when drying, the drying temperature is higher than the burning point or the melting point of the filling sheet; the double-runner sand core is further combined with the external mold and other sand cores and then cast; during casting, the size of the gap space is smaller than the capillary length of the casting fluid; and demolding to obtain a finished product of the double-runner turbocharger shell. The problem of dividing wall department casting and filling the not smooth cold shut defect and overlap burr that leads to of type process exhaust is avoided to this application.)

1. A double-flow-passage sand core assembly process of a double-flow-passage turbocharger is characterized by comprising the following steps of:

bonding the first runner sand core and the second runner sand core to form a combined sand core; when the two runner sand cores are combined, a fit clearance is reserved between the fit surfaces of the two sand cores, meanwhile, a filling piece which is inflammable or easy to melt and has the size equal to the fit clearance between the two sand cores is placed in the fit clearance, and the first runner sand core and the second runner sand core are bonded in place after the bonding surfaces of the filling piece are coated with bonding agents;

after the adhesive is cured at room temperature, dip-coating the combined sand core;

drying the dip-coated combined sand core under the ventilation condition to prepare a double-runner sand core; during drying, the drying temperature is higher than the ignition point or the melting point of the filling sheet, so that the filling sheet is spontaneously combusted or melted, and a gap space with the thickness equal to that of the filling sheet is formed at the matching gap.

2. The dual-channel sand core assembly process of the dual-channel turbocharger according to claim 1, characterized in that: the filling sheet is cloth, paper sheet or plastic product.

3. The dual-channel sand core assembly process of the dual-channel turbocharger according to claim 1, characterized in that: the drying time is 2-3h, and the drying temperature is higher than 150 ℃.

4. The dual-channel sand core assembly process of the dual-channel turbocharger according to claim 1, characterized in that: the adhesive used in the bonding is a sand core adhesive, and the coating used in the dip-coating operation is a casting coating.

5. The dual-channel sand core assembly process of the dual-channel turbocharger according to claim 1, characterized in that: the size of the gap space does not exceed 0.15 mm.

6. A dual-flow turbocharger housing casting process comprising the dual-flow turbocharger sand core assembly process of any one of claims 1-5, wherein: the double-runner sand core is further combined with the external mold and other sand cores and then cast; during casting, the size of the gap space is smaller than the capillary length of the casting fluid, so that the gap space can be smoothly exhausted in the casting process;

and demolding to obtain a finished product of the double-runner turbocharger shell.

7. The dual-runner sand core of claim 6, wherein: the casting fluid used in the casting is molten iron or molten steel.

Technical Field

The invention relates to the technical field of sand core casting, in particular to a double-flow-channel sand core assembly process of a double-flow-channel turbocharger and a casting process of a double-flow-channel turbocharger shell.

Background

At present, more and more turbochargers adopt double-flow turbine shells, and compared with a single-flow turbine shell, the double-flow turbine shell has a more complex internal structure, and two sand cores are required to be used in large-scale batch production;

after two runner sand cores are produced respectively, the two runner sand cores are combined, dip-coated and dried, casting production is carried out, a partition wall is formed after the two runner sand cores are combined, and a matching surface is arranged between the two runner sand cores.

Two psammitolites in conventional double-flow turbine casing are in the combination bonding step, can wholly dip-coat the postbaking, also can dip-coat respectively and dry the postbonding again, but above two kinds of modes all can have certain problem:

when the coating is dipped and dried firstly, the coating can block gaps at the matching surface, and cold shut defects can be generated at the partition wall due to unsmooth air exhaust of the gaps in the casting process after drying;

during bonding after dip-coating is dried respectively, because can remain coating on the fitting surface, the clearance that produces in bonding back fitting surface department is great, and casting fluid can dip in clearance department and produce the overlap burr in the casting process, and this just needs artifical the polishing to get rid of, and not only the volume of polishing is difficult to control, influences turbocharger's performance, has still increased artifical process, increase cost.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a double-flow-passage sand core assembly process of a double-flow-passage turbocharger and a casting process of a double-flow-passage turbocharger shell, which solve the problem of cold shut defect caused by unsmooth exhaust in the casting and filling process of a partition wall, improve the casting qualification rate of the upper-flow-passage turbocharger shell, avoid the generation of flash and burr on the fitting surface, omit the later polishing and correction work and ensure the integrity of the shape of the partition wall. The technical scheme adopted by the invention is as follows:

the invention provides a double-flow-passage sand core assembly process of a double-flow-passage turbocharger, which comprises the following steps:

bonding the first runner sand core and the second runner sand core to form a combined sand core; when the two runner sand cores are combined, a fit clearance is reserved between the fit surfaces of the two sand cores, meanwhile, a filling piece which is inflammable or easy to melt and has the size equal to the fit clearance between the two sand cores is placed in the fit clearance, and the first runner sand core and the second runner sand core are bonded in place after the bonding surfaces of the filling piece are coated with bonding agents;

after the adhesive is cured at room temperature, dip-coating the combined sand core;

drying the dip-coated combined sand core under the ventilation condition to prepare a double-runner sand core; during drying, the drying temperature is higher than the ignition point or the melting point of the filling sheet, so that the filling sheet is spontaneously combusted or melted, and a gap space with the thickness equal to that of the filling sheet is formed at the matching gap.

Further, the filling sheet is cloth, paper sheet or plastic product.

Further, the drying time is 2-3h, and the drying temperature is higher than 150 ℃.

Further, the binder used in the bonding is a sand core binder, and the coating used in the dip coating operation is a casting coating.

Further, the size of the gap space does not exceed 0.15 mm.

The invention also provides a casting process of the double-flow-passage turbocharger shell, which is characterized in that the double-flow-passage sand core, the outer mold and other sand cores are further combined and then cast; during casting, the size of the gap space is smaller than the capillary length of the casting fluid, so that the gap space can be smoothly exhausted in the casting process;

and demolding to obtain a finished product of the double-runner turbocharger shell.

Further, the casting fluid used in the casting is molten iron or molten steel.

The invention has the advantages that: the filling sheet is used for avoiding the fit clearance between the two sand cores from being blocked by the coating in the dip-coating process, and meanwhile, the filling sheet is made of flammable and fusible materials, so that the filling sheet can be directly melted or combusted in the drying process, additional working procedures are not needed, the cost is saved, the quality of the double-runner sand core is improved, the exhaust efficiency in the later-stage casting and mold filling process can be ensured, and the product percent of pass is improved;

because the gap space after drying is very small, the size of the gap space is smaller than the capillary length of the casting fluid, and the surface tension of the casting fluid is enough to support the gravity of the casting fluid, so that the casting fluid cannot enter the gap space, the smooth exhaust in the casting and mold filling process is ensured, the flash and burr generated at the partition wall when high-temperature molten iron flows into the gap space in the casting and mold filling process are avoided, the subsequent polishing and finishing work is avoided, the cost is reduced, and the product quality is improved.

Drawings

FIG. 1 is a schematic structural diagram of the present invention.

In the figure: 1-a first runner sand core, 2-a second runner sand core, 3-a filling sheet, and 4-a partition wall.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to fig. 1, an embodiment of the present application first provides an assembly process of a dual-flow-channel sand core of a dual-flow-channel turbocharger:

bonding the first runner sand core 1 and the second runner sand core 2 to form a combined sand core; when the two runner sand cores are combined, a fit clearance is reserved between the fit surfaces of the two sand cores, meanwhile, a filling sheet 3 which is inflammable or easy to melt and has the size equal to the fit clearance between the two sand cores is placed in the fit clearance, and the first runner sand core 1 and the second runner sand core 2 are bonded in place after the bonding surfaces of the filling sheet are coated with bonding agents;

after the adhesive is cured at room temperature, putting the combined sand core into a coating box for dip-coating operation, standing for 3-5 seconds, and taking out the combined sand core to ensure that the coating is uniformly paved on the surface of the combined sand core, wherein the coating cannot enter a fit clearance under the action of the filling sheet 3;

putting the dip-coated combined sand core into a drying equipment assembly line, drying under a ventilation condition, ensuring that the drying temperature is higher than the burning point or the melting point of the filling sheet 3, manufacturing a double-channel sand core, and forming a gap space with the thickness equal to that of the filling sheet 3 at a fit gap; in the drying process, the drying temperature reaches the ignition point or the melting point of the filling sheet 3, and the filling sheet 3 meets the spontaneous combustion condition or the melting condition under the condition of air combustion supporting, so that the filling sheet 3 is spontaneously combusted or melted, and no coating or filling sheet impurities exist in the gap space.

Because the filling sheet is spontaneously combusted or melted in the drying process, a process of removing the filling sheet 3 is not required to be additionally added, the cleanliness of a gap space is ensured, the gas at the division wall in the casting and filling process can be smoothly discharged through the gap space, and the cold insulation defect caused by unsmooth exhaust in the casting and filling process at the division wall of the double-flow-channel turbine shell is avoided.

Specifically, the filling piece 3 exceeds the fitting clearance by not less than 0.2mm, i.e., it is ensured that the coating does not enter the fitting clearance in the dip coating operation.

Specifically, the filling sheet 3 is a cloth, a paper sheet or a plastic product, is used as a good inflammable fusible material, has a low required ignition point or melting point, and meets the spontaneous combustion or self-melting condition in the drying process; preferably, the filling sheet 3 is made of low-density polyethylene material, and the self-melting effect is better.

Specifically, the drying time is 2-3h, and the drying temperature is higher than 150 ℃; when the filling sheet 3 is made of cotton cloth such as paper, pearl wool and the like or polyethylene material products, the drying temperature is 150-300 ℃, and constant continuous drying at 200 ℃, 220 ℃ and 250 ℃ can be selected; when the filling sheet 3 is cloth, the drying temperature is more than 280 ℃.

Specifically, the binder used in the bonding is a sand core binder, and the coating used in the dip coating operation is a casting coating.

In addition, the embodiment of the application also provides a casting process of the double-channel turbocharger housing, which comprises the following steps: further combining the double-runner sand core with the external mold and other sand cores, and filling casting fluid with the temperature of more than 1300 ℃ for casting and mold filling; during casting, the size of the gap space is smaller than the capillary length of the casting fluid, so that gas at the partition wall 4 can be smoothly discharged through the gap space;

after the casting is finished, cooling to a certain temperature, and then demolding to obtain a double-runner turbocharger shell finished product; the cooling temperature is below 400 ℃, and the demolding quality is ensured.

Specifically, the casting fluid used in the casting is molten iron or molten steel; the composition and amount of each reagent is well known to those skilled in the art, and each reagent is commercially available, so the composition of each reagent is not described herein.

In the present application, the relationship between capillary length and surface tension coefficient is:wherein γ is a surface tension coefficient, ρ is a fluid density, g is a gravitational acceleration, and the test results of the influences of the size of the filling sheet 3 and the size of the gap space on the number of burrs and cold shut defects under the conditions that the casting fluid is 436L type high temperature resistant stainless steel and the casting temperature is 1600 ℃ are shown in the following table:

therefore, the casting effect is better when the size of the clearance space is 0.04-0.12 mm; when the size of the clearance space is 0.05mm-0.1mm, the surface tension effect is most obvious, and the casting effect is best; therefore, the exhaust requirement of the partition wall 4 in the casting and mold filling process is met, the casting and mold filling quality is improved, simultaneously, the flash and burr generated at the joint of the gap space and the partition wall 4 are avoided, and the subsequent polishing and finishing work is avoided.

The double-runner sand core cast by the process has better quality at the position 4 of the partition wall during casting, the shape of the partition wall 4 meets the design requirements better, the generation of flash and burr is reduced, the product percent of pass is improved, and the subsequent polishing and finishing work is avoided.

Finally, it should be noted that the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention has been described in detail with reference to examples, it should be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.