CN1280039C - Silicon carbide shell production and use in directional solidification - Google Patents
Silicon carbide shell production and use in directional solidification Download PDFInfo
- Publication number
- CN1280039C CN1280039C CN 03111144 CN03111144A CN1280039C CN 1280039 C CN1280039 C CN 1280039C CN 03111144 CN03111144 CN 03111144 CN 03111144 A CN03111144 A CN 03111144A CN 1280039 C CN1280039 C CN 1280039C
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- Prior art keywords
- silicon carbide
- shell
- directional solidification
- carbide section
- section mould
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- 229910010271 silicon carbide Inorganic materials 0.000 title claims abstract description 54
- HBMJWWWQQXIZIP-UHFFFAOYSA-N silicon carbide Chemical compound [Si+]#[C-] HBMJWWWQQXIZIP-UHFFFAOYSA-N 0.000 title claims abstract description 42
- 238000007711 solidification Methods 0.000 title claims abstract description 34
- 230000008023 solidification Effects 0.000 title claims abstract description 34
- 238000004519 manufacturing process Methods 0.000 title description 3
- 229910052593 corundum Inorganic materials 0.000 claims abstract description 12
- 239000010431 corundum Substances 0.000 claims abstract description 12
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 claims description 15
- 229910045601 alloy Inorganic materials 0.000 claims description 7
- 239000000956 alloy Substances 0.000 claims description 7
- 239000000843 powder Substances 0.000 claims description 7
- 239000002002 slurry Substances 0.000 claims description 6
- 238000002360 preparation method Methods 0.000 claims description 5
- 238000009413 insulation Methods 0.000 claims description 4
- 239000000203 mixture Substances 0.000 claims 1
- 238000005266 casting Methods 0.000 abstract description 21
- 239000013078 crystal Substances 0.000 abstract description 3
- 230000002349 favourable effect Effects 0.000 abstract 1
- 239000002075 main ingredient Substances 0.000 abstract 1
- 230000005855 radiation Effects 0.000 description 13
- 238000000034 method Methods 0.000 description 9
- 210000001787 dendrite Anatomy 0.000 description 8
- 238000002425 crystallisation Methods 0.000 description 7
- 238000003763 carbonization Methods 0.000 description 5
- 230000008025 crystallization Effects 0.000 description 5
- 238000007713 directional crystallization Methods 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- 238000001816 cooling Methods 0.000 description 3
- 230000005496 eutectics Effects 0.000 description 3
- 239000007791 liquid phase Substances 0.000 description 3
- 239000004576 sand Substances 0.000 description 3
- 239000000377 silicon dioxide Substances 0.000 description 3
- 229910001338 liquidmetal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000012071 phase Substances 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 229910000601 superalloy Inorganic materials 0.000 description 2
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 229910052710 silicon Inorganic materials 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
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- Turbine Rotor Nozzle Sealing (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The present invention relates to a silicon carbide shell which is characterized in that the main ingredient of the shell is silicon carbide, the shell wall of the shell has a layer structure, and a corundum layer can be lined in the silicon carbide layer. The shell wall of the shell can be thickened layer by layer from inside to outside. The present invention has the advantages of sufficient strength, favorable thermal conductivity and low cost, and is especially suitable for casting large-size directional solidification crystal pieces.
Description
Technical field:
The present invention relates to the foundry engieering of metal, a kind of alloy directionally solidified silicon carbide section mould that is used for is provided especially.
Background technology:
The energy is the power of the development of the national economy, and industrial high performance gas-turbine engine is one of clean at present energy power system, the manufacturing technology of the empty engine blade of the main source of gas-turbine wheel manufacturing technology pilotage.Therefore, Xian Jin high temperature alloy directional solidification technique also is used to develop industrial gas turbine engine bucket.The directional solidification of blade is meant controls direction of heat flow in casting process, make crystallization along the growth of parallel blade principal axes of stress direction, forms the foundry engieering of the columnar structure of oriented growth.Because the blade of directional solidification crystalline structure has been eliminated horizontal crystal boundary, thereby its performance and all being greatly improved service life.
Directional solidification is normally carried out in vaccum sensitive stove, and the directional solidification process is to control hot-fluid with the purpose that reaches crystallographic orientation by heat radiation.The heat radiation of directional solidification process can be divided into three phases:
Open stage beginning, opening stage beginning of directional solidification, heat mainly sheds by the chassis of water mold, and foundry goods carries out heat exchange by the heat conduction with crystallizer.This stage is based on the heat conduction, is auxilliary with the heat radiation of casting mold.So the initial period of directional solidification is the stage based on the heat conduction.
Interstage, prolongation along with the directional solidification time, the part of solidifying of foundry goods increases, the liquid-solid boundary of crystallographic orientation solidification zone is more and more far away apart from crystallizer, the influence of crystallizer cooling capacity weakens gradually, the heat exchange pattern heat radiation also constantly diminishes, and the influence of the heat radiation of casting mold heat radiation strengthens gradually.When casting solidification reaches when middle part, the heat conduction and the heat radiation of casting mold of crystallizer were dispelled the heat to play a role jointly and were kept the foundry goods directional solidification and proceed this moment.So the interstage of directional solidification plays a role jointly with heat conduction and heat radiation.
Final stage, when the final stage that is directionally solidified into of foundry goods, heat radiation and the initial period of this moment have reversed, and it is the heat radiation heat radiation based on casting mold, and the heat conducting and radiating of crystallizer is auxilliary.Therefore, the final stage of foundry goods directional solidification is the stage based on heat radiation.
The radiating mode difference of the three phases of directional solidification, the heat-sinking capability difference, the upgrowth situation of cylindrulite is also different.Basically be that the last stage is thin, after-stage is thick.For the small size blade of aero-engine, the radiating mode of directional solidification is in the early stage of opening stage beginning and interstage, and the heat-sinking capability of casting mold also is not outstanding especially to the influence of directional solidification, and the casting mold of existing corundum material still is feasible.But for the large scale linear leaf of industrial high performance gas-turbine engine, for stability and the efficient that guarantees its crystallographic orientation, it is particularly important that the raising of casting mold heat-sinking capability just seems.
Further, the technology crux of directional solidification is the thermograde in the control solidification zone liquid phase.Thermograde is big more, and it is straight and upright more, fine and close more that cylindrulite is grown.For quality and the efficient that guarantees directional solidification, generally all manage to improve the thermograde of directional solidification.Improving the thermograde usual practice is the heating-up temperature that improves the casting mold heater, improves the pouring temperature of alloy and the capacity of heat transmission of raising crystallizer etc.Advanced directional solidification technique is to adopt the liquid metal cooling method.Be about to casting mold and crystallizer and pull out in the direct later on immersion low melting point of heater, the higher boiling liquid metal, utilize the thermal capacity of metal to make the solidification zone Quench, the thermograde of liquid phase is increased substantially.The method of above-mentioned raising thermograde all must realize by the heat absorption and the heat radiation of casting mold.Therefore, under similarity condition, the thermal conductivity that improves casting mold plays an important role for the thermograde that improves the solidification zone liquid phase.This is because the thermal conductivity of casting mold is strong, can dwindle the scope of solidification zone, helps improving thermograde; The casting mold thermal conductivity helps to strengthen solidifying the heat conduction of foundry goods by force simultaneously, also helps improving thermograde.In addition, improve the thermal conductivity of casting mold, help improving the thermograde of directional solidification, also help the cylindrulite growth.This is that dendritic growth needs local overcooling because cylindrulite is made of dendrite, and degree of supercooling is big more, and dendrite is thin more, and mechanical property is good more, and local overcooling is caused by cooldown rate, and cooldown rate is directly related with the heat-sinking capability of casting mold.This shows that the thermal conductivity that improves casting mold is the important measures that improve blades oriented crystalline quality and efficient.
The technology contents of invention:
The purpose of this invention is to provide a kind of silicon carbide section mould, it has enough intensity and good thermal conductivity, and cost is lower, is particularly suitable for casting large-sized directional solidification crystallization part.
The invention provides a kind of silicon carbide section mould, it is characterized in that: this shell main component is a carborundum.
The shell wall of silicon carbide section mould of the present invention can have layer structure, can also be lined with corundum layer in the silicon carbide layer.Shell is progressive additive preferably from inside to outside.
Silicon carbide section mould of the present invention is alternately to be coated with extension by carbonization silica sand and/or schmigel and Ludox slurry, again through 950～1600 ℃ of insulations 20～60 minutes, fires and forms.
Among the preparation method of above-mentioned silicon carbide section mould, it is characterized in that described Ludox slurry contains corundum and/or carborundum powder, viscosity is 27～37 seconds (a Chinese Industrial Standards (CIS) flow cup).
Silicon carbide section mould of the present invention is specially adapted to the directional solidification of high temperature alloy workpiece.
Because carborundum is a kind of black crystals, has higher thermal emissivity rate, and has higher refractoriness simultaneously, the lower coefficient of expansion and than characteristics such as stable chemical property, therefore, the prepared silicon carbide section mould that goes out has enough intensity and good thermal conductivity, is suitable for casting large-sized crystallographic orientation spare, in addition because the carborundum wide material sources, thus with low cost.
Description of drawings:
Fig. 1 is the temperature lowering curve of single coupon silicon carbide section mould:
Fig. 2 is the temperature lowering curve of many coupon silicon carbide section moulds;
Fig. 3 is that many coupon silicon carbide section moulds use the back photo;
Fig. 4 is the coupon metallographic structure photo that full shell mould silicon carbide section mould draws;
Fig. 5 is the coupon metallographic structure photo that half shell mould carbonization shell draws;
The coupon metallographic structure photo that Fig. 6 draws for the corundum type shell;
Fig. 7 is the directional crystalli zation blade photo that full shell mould silicon carbide section mould draws;
Fig. 8 is the directional crystalli zation blade photo that half shell mould silicon carbide section mould draws.
The specific embodiment:
Embodiment 1
Ludox mixes stirring with schmigel, reach 30 seconds (Chinese Industrial Standards (CIS) flow cup) until viscosity, makes slurry.On the wax pattern (300mm is long) of single coupon, many coupons, industrial gas turbine engine bucket, be coated with the hanging material respectively, spread one deck 60～80# carborundum powder, 3 times repeatedly; Be coated with the hanging material, spread the 36# carborundum powder, 3 times repeatedly; Be coated with the hanging material, spread the 24# carborundum powder, 6 times repeatedly; After the shell dewaxing, put into heating furnace and be warmed up to 950～1050 ℃ of insulations 40 minutes, obtain the single coupon of 12 layers of structure, many coupons, the full shell mould silicon carbide section mould of industrial gas turbine engine bucket respectively.
Embodiment 2
With embodiment 1 different being, earlier substitute the carbonization silica sand with schmigel, behind layer 6, still use the carbonization silica sand, obtain the single coupon of 12 layers of structure, many coupons, industrial gas turbine engine bucket half shell mould silicon carbide section mould respectively.
Embodiment 3
The full shell mould silicon carbide section mould of single coupon, many coupons and the corundum shell of half shell mould silicon carbide section mould and contrast are put into cooler bin respectively,, heat-sinking capability is measured by survey its temperature-fall period with thermocouple.The results are shown in Figure 1 and Fig. 2.As seen, no matter be single coupon shell, or the combination shell of many coupons; No matter being from 1300 ℃, still is to measure its temperature-fall period behind 1600 ℃ of roasts all to show same cooling trend, and promptly the rate of temperature fall of silicon carbide section mould is greater than the corundum shell.And the rate of temperature fall of full silicon carbide section mould is better than partial carbonization silicon shell.
Embodiment 4
Use the M41 cast superalloy, three kinds of shells using many coupons are respectively pressed the remelting and the directed crystallisation process of alloy in directional crystallization furnace, and the pulling rate that divides with 7mm/ has carried out the crystallographic orientation test.The result all successfully draws out the crystallographic orientation coupon, draws the many coupon silicon carbide section moulds in back and uses the back photo to see Fig. 3, shows that this shell not only has suitable intensity can bear the elevated temperature strength of directional solidification process, and also has good deformability.So just can avoid big blade in the crystallographic orientation process, to produce hot tearing.Coupon is checked its cylindrulite growing state after corroding, consequently, the directional columnargrain that draws out coupon with silicon carbide section mould is than the directional columnargrain of corundum shell and straight, and disconnected crystalline substance is also few.The coupon crystallization situation that full shell silicon carbide section mould draws is better than half shell silicon carbide section mould again.Fig. 4,5,6 illustrates the crystallographic orientation situation of three kinds of coupons that three kinds of shells pull out.The enduring quality of the crystallographic orientation coupon of three kinds of shells and its metallographic structure are summarized as follows table.
The high-temperature and durable of three kinds of shell coupons and metallographic structure
| Shell | 980℃，82MPa | Metallographic structure |
| Full shell | 162 hours | One time dendrite is thin, and secondary dendrite is short, and carbide is thin, and the carbide eutectic is few |
| Half shell | 115.5 hour | One time dendrite is thin, and secondary dendrite is long, and carbide is little, and the carbide eutectic is many slightly |
| Corundum | 79.08 hour | One time dendrite is long, and secondary dendrite is thick, and carbide is big, and bulk carbide eutectic is many |
Embodiment 5
The blade construction complexity, corner is many and sharp-pointed; The large-scale blades stature is big, heavy, setting time is long, elevated temperature strength for shell requires high, use the M11 cast superalloy, in directional crystallization furnace, press the remelting and the directed crystallisation process of the big blade of corundum shell, divide pulling rate to carry out the crystallographic orientation test with the full shell and the half shell carborundum type of embodiment 1 and 2 respectively with 7mm/.Fig. 7 and 8 is respectively the crystallization situation after the directional crystalli zation blade corrosion that draws out with full hull shape and half shell mould silicon carbide section mould.Complete as seen from the figure shell and half shell silicon carbide section mould all satisfy the requirement of big blades oriented crystallization hot strength of investment shell.And its cylindrulite growth is thin and straight, and effect is very satisfactory.
Claims (9)
1, a kind of silicon carbide section mould is characterized in that: this shell composition is a carborundum.
2, according to the described silicon carbide section mould of claim 1, it is characterized in that: the shell wall of this shell has layer structure.
3, according to the described silicon carbide section mould of claim 2, it is characterized in that: be lined with corundum layer between described silicon carbide layer.
4, according to claim 2 or 3 described silicon carbide section moulds, it is characterized in that: described shell shell wall from inside to outside successively thickens.
5, the preparation method of the described silicon carbide section mould of a kind of claim 2 is characterized in that described shell alternately is coated with extension by carborundum powder and Ludox slurry, through 950～1600 ℃, insulation 30～60 minutes, fires and forms again.
6, the preparation method of the described silicon carbide section mould of a kind of claim 2 is characterized in that described shell alternately is coated with extension by carborundum powder and schmigel and Ludox slurry, again through 950～1600 ℃, insulation 30～60 minutes, fires and forms.
7, according to the preparation method of claim 5 or 6 described silicon carbide section moulds, it is characterized in that described Ludox slurry contains corundum and carborundum powder, viscosity is 27～37 seconds.
8, the described silicon carbide section mould of one of claim 1～3 is used for the directional solidification of high temperature alloy workpiece.
9, the described silicon carbide section mould of claim 4 is used for the directional solidification of high temperature alloy workpiece.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03111144 CN1280039C (en) | 2003-03-10 | 2003-03-10 | Silicon carbide shell production and use in directional solidification |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 03111144 CN1280039C (en) | 2003-03-10 | 2003-03-10 | Silicon carbide shell production and use in directional solidification |
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| Publication Number | Publication Date |
|---|---|
| CN1530192A CN1530192A (en) | 2004-09-22 |
| CN1280039C true CN1280039C (en) | 2006-10-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN 03111144 Expired - Fee Related CN1280039C (en) | 2003-03-10 | 2003-03-10 | Silicon carbide shell production and use in directional solidification |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102744368B (en) * | 2012-07-19 | 2013-12-25 | 无锡范尼韦尔工程有限公司 | Method for maintaining viscosity of sizing agent for investment casting shell |
| CN104259390B (en) * | 2012-10-22 | 2016-07-06 | 宁波吉威熔模铸造有限公司 | A kind of casting method of car engine cover |
| CN104325077A (en) * | 2012-10-22 | 2015-02-04 | 宁波吉威熔模铸造有限公司 | Casting method of vehicle engine piston |
| CN104226898A (en) * | 2012-10-22 | 2014-12-24 | 宁波吉威熔模铸造有限公司 | Investment casting method for bucket tooth |
| CN102861873B (en) * | 2012-10-22 | 2015-06-10 | 宁波吉威熔模铸造有限公司 | Casting method of gear |
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Granted publication date: 20061018 Termination date: 20110310 |