Method for eliminating surface porosity of hollow blade castings

Abstract

The application provides a method for eliminating the surface loose of a hollow blade casting, comprising the following steps: S1. Preparing a silica sol filler, dropping the filler into a cavity of a ceramic core, and drying to obtain a ceramic core with the filler; S2. Placing the ceramic core into a wax mold mold, injecting medium-temperature wax into the single-blade wax mold mold, and pressing to obtain a blade wax mold with the ceramic core; S3. Bonding the blade wax mold with a pouring riser, and combining the blade wax mold with a pouring system; S4. Shelling the blade wax mold, and dewaxing to obtain a blade mold shell; S5. Roasting the blade mold shell, and wrapping the blade mold shell with high-temperature-resistant ceramic cotton; S6. Preheating the mold shell, melting a mother alloy, pouring the mother alloy into the mold shell, and cooling to obtain a casting; S8. Removing the pouring riser and the ceramic core on the casting; and S9. Detecting the casting to obtain a hollow blade casting. The inner cavity of the ceramic core is filled with the silica sol filler, the heat storage capacity of the ceramic core is reduced, the ceramic core is cooled after pouring is accelerated, the surface loose defect problem of the hollow blade casting is solved, and the qualified rate of the casting can be increased by 20%-30%.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of casting forming process, and particularly relates to a method for eliminating surface loose of hollow blade castings. BACKGROUND

[0002] At present, most of the hollow blade castings of precision casting have surface loose defects. The current solution is to reduce the mold shell and pouring temperature to solve the problem, but it will cause the castings to be unable to complete the filling, resulting in the castings to have underfilling problems. The present application fills the silica sol filler in the inner cavity of the ceramic core, and then performs wax pressing, shell forming and pouring with the ceramic core, so as to prevent the surface of the hollow blade from being loose, that is, without affecting the remaining metallurgical quality of the castings, the problem of surface loose of the hollow blade is solved. SUMMARY

[0003] The present application aims to overcome and supplement the deficiencies in the prior art, and provides a method for eliminating surface loose of hollow blade castings. The silica sol filler is filled in the inner cavity of the ceramic core, and then the wax pressing, tree forming and shell forming are performed using the ceramic core, and finally pouring is performed. The silica sol filler filled in the inner cavity of the ceramic core can effectively reduce the heat storage capacity of the ceramic core, so as to accelerate the cooling of the ceramic core after pouring, thereby solving the problem of surface loose defects of the hollow blade. The technical scheme adopted by the present application is as follows:

[0004] A method for eliminating surface loose of hollow blade castings, comprising the following steps:

[0005] S1. Preparing silica sol filler, and dropping the prepared silica sol filler into the cavity of the ceramic core by using a dropper, and drying to obtain a ceramic core with filler;

[0006] S2. Placing the ceramic core with filler into a wax mold mold, and injecting medium-temperature wax into the single-blade wax mold mold by using a wax pressing machine to press a blade wax mold with ceramic core;

[0007] S3. Bonding the blade wax mold and the pouring system by using bonding wax, and then combining the blade wax mold and the pouring system by using a hot knife heating method;

[0008] S4. Forming a shell for the blade wax mold combined in step S3, and then performing mold shell dewaxing to obtain a blade shell;

[0009] S5. Baking the blade shell, and wrapping the shell with high-temperature-resistant ceramic cotton after cooling;

[0010] S6. Preheating the shell in step S5, melting the master alloy, and pouring the master alloy into the shell, and cooling the castings in the furnace under vacuum for 5-60 minutes to obtain the castings, and taking the castings out of the shell chamber for cooling;

[0011] S8, remove the pouring and runner on the casting, and remove the ceramic core with the core removal kettle;

[0012] S9, the casting of step S8 is detected, and the hollow blade casting is obtained after the detection is qualified.

[0013] Preferably, the method for eliminating the surface loose of the hollow blade casting, wherein: the silica sol filler of step S1 comprises 70%-75% zircon sand, 18%-27% silica sol and 3%-7% cobalt aluminate by mass percentage.

[0014] Preferably, the method for eliminating the surface loose of the hollow blade casting, wherein: the injection temperature in step S2 is 70-80℃, and the injection pressure is 5-10 bar.

[0015] Preferably, the method for eliminating the surface loose of the hollow blade casting, wherein: the temperature of the mold shell dewaxing in step S4 is 150-180℃, the dewaxing time is 10-20 min, and the dewaxing pressure is 5-10 bar.

[0016] Preferably, the method for eliminating the surface loose of the hollow blade casting, wherein: the baking temperature in step S5 is 800-1000℃, and the baking time is 8-12 h.

[0017] Preferably, the method for eliminating the surface loose of the hollow blade casting, wherein: the preheating temperature in step S6 is 900-1200℃, and the preheating time is 8-12 h.

[0018] Preferably, the method for eliminating the surface loose of the hollow blade casting, wherein: the master alloy in step S6 is K447A or K452, and the melting temperature of the master alloy is 1400-1550℃.

[0019] Preferably, the method for eliminating the surface loose of the hollow blade casting, wherein: the vacuum degree in step S6 is ≤0.01 Pa.

[0020] Advantages of the present application:

[0021] (1) The method for eliminating the surface loose of the hollow blade casting, the silica sol filler is composed of refractory material zircon sand, binder silica sol and grain refiner cobalt aluminate, after filling the silica sol filler in the inner cavity of the ceramic core, then using the ceramic core to press the wax, and then performing the tree assembling, shell making, dewaxing, baking and cotton wrapping processes, finally pouring, the silica sol filler filled in the inner cavity of the ceramic core can effectively reduce the heat storage capacity of the ceramic core, thereby accelerating the cooling of the ceramic core after pouring, thereby solving the problem of surface loose defects existing in the hollow blade casting, and the qualified rate of the casting can be improved by 20%-30%. DETAILED DESCRIPTION

[0022] The application will be further described in connection with specific embodiments.

[0023] Example 1

[0024] A method for eliminating surface porosity of a hollow blade casting, wherein the method comprises the following steps:

[0025] S1. Preparing a silica sol filler, the silica sol filler comprising 70% zircon sand, 27% silica sol and 3% cobalt aluminate by mass percentage; dropping the prepared silica sol filler into the cavity of the ceramic core using a dropper, and drying at room temperature for 8h to obtain a ceramic core with filler;

[0026] S2. Placing the ceramic core with filler into a wax mold mold, and injecting medium-temperature wax into the single-blade wax mold mold using a wax press, the injection temperature being 70℃ and the injection pressure being 5bar, to press out a blade wax mold with ceramic core;

[0027] S3. Bonding the blade wax mold and the sprue and runner through bonding wax, and then combining the blade wax mold and the gating system using a hot knife heating method;

[0028] S4. Shelling the blade wax mold combined in step S3, and then performing mold shell dewaxing, the mold shell dewaxing temperature being 150℃, the dewaxing time being 20min, and the dewaxing pressure being 5bar, to obtain a blade mold shell;

[0029] S5. Firing the blade mold shell, the firing temperature being 800℃ and the firing time being 12h, and wrapping the mold shell with high-temperature-resistant ceramic wool after cooling;

[0030] S6. Preheating the mold shell of step S5, the preheating temperature being 900℃ and the preheating time being 12h, and pouring a master alloy into the mold shell after melting the master alloy, the master alloy being K447A and the master alloy melting temperature being 1400℃, and cooling the alloy in the furnace under vacuum for 5min to obtain a casting, the vacuum degree being ≤0.01Pa, and cooling the casting in the mold shell chamber;

[0031] S8. Removing the sprue and runner on the casting, and removing the ceramic core using a core removal kettle;

[0032] S9. Detecting the casting of step S8, performing visual detection, fluorescence detection and radiation detection, and obtaining a hollow blade casting after the detection is qualified.

[0033] Example 2

[0034] A method for eliminating surface porosity of a hollow blade casting, wherein the method comprises the following steps:

[0035] S1. A silica sol filler is prepared, which includes 72% zircon sand, 21% silica sol and 7% cobalt aluminate by mass percentage; the prepared silica sol filler is dropped into the cavity of the ceramic core by using a dropper, and dried at room temperature for 8h to obtain a ceramic core with filler;

[0036] S2. The ceramic core with filler is placed into a wax mold mold, and a medium-temperature wax is injected into the single-blade wax mold mold by using a wax injection machine, an injection temperature is 75°C, an injection pressure is 7 bar, and a blade wax mold with ceramic core is pressed out;

[0037] S3. The blade wax mold is bonded with a pouring and feeding system by using bonding wax, and then the blade wax mold is combined with the pouring and feeding system by using a hot knife heating method;

[0038] S4. The combined blade wax mold of step S3 is shell-made, and then shell dewaxing is performed, a shell dewaxing temperature is 170°C, a dewaxing time is 15 min, a dewaxing pressure is 8 bar, and a blade shell is obtained;

[0039] S5. The blade shell is fired, a firing temperature is 900°C, a firing time is 10h, and after cooling, the shell is wrapped with high-temperature-resistant ceramic cotton;

[0040] S6. The shell of step S5 is preheated, a preheating temperature is 900-1200°C, a preheating time is 10h, a master alloy is melted and poured into the shell, the master alloy is K447A, a master alloy melting temperature is 1500°C, after pouring the alloy, the casting is cooled in the furnace under vacuum for 20 min to obtain a casting, a vacuum degree is ≤0.01 Pa, and the casting is taken out of the shell chamber and cooled;

[0041] S8. The pouring and feeding of the casting is removed, and the ceramic core is removed by using a core removal kettle;

[0042] S9. The casting of step S8 is detected, visual detection, fluorescence detection and ray detection are performed, and after the detection is qualified, a hollow blade casting is obtained.

[0043] Example 3

[0044] A method for eliminating surface loose of a hollow blade casting, wherein the method comprises the following steps:

[0045] S1. A silica sol filler is prepared, which includes 72% zircon sand, 21% silica sol and 7% cobalt aluminate by mass percentage; the prepared silica sol filler is dropped into the cavity of the ceramic core by using a dropper, and dried at room temperature for 8h to obtain a ceramic core with filler;

[0046] S2. The ceramic core with filler is placed into a wax mold mold, and a medium-temperature wax is injected into the single-blade wax mold mold by using a wax injection machine, an injection temperature is 75°C, an injection pressure is 7 bar, and a blade wax mold with ceramic core is pressed out;

[0047] S3, the blade wax mold is bonded with the pouring riser through the bonding wax, and then the blade wax mold is combined with the pouring system by using the hot knife heating method;

[0048] S4, the blade wax mold combined in step S3 is shell making, and then the shell is dewaxed, the shell dewaxing temperature is 180 DEG C, the dewaxing time is 10 min, and the dewaxing pressure is 10 bar, so that the blade shell is obtained;

[0049] S5, the blade shell is baked, the baking temperature is 1000 DEG C, the baking time is 8h, and after cooling, the shell is wrapped with high-temperature-resistant ceramic cotton;

[0050] S6, the shell of step S5 is preheated, the preheating temperature is 1200 DEG C, the preheating time is 8h, and the master alloy is melted and poured into the shell, the master alloy is K452, the master alloy melting temperature is 1550 DEG C, after pouring the alloy, the casting is cooled in the furnace under vacuum for 60 min, the vacuum degree is less than or equal to 0.01 Pa, and the casting is taken out of the shell chamber and cooled;

[0051] S8, the pouring riser on the casting is removed, and the ceramic core is removed by using the core removal kettle;

[0052] S9, the casting of step S8 is detected, visual detection, fluorescence detection and radiation detection are carried out, and the hollow blade casting is obtained after the detection is qualified.

[0053] The method for eliminating the surface loose of the hollow blade casting of the application, the silica sol filler is composed of refractory material zircon sand, binder silica sol and grain refiner cobalt aluminate, after filling the silica sol filler in the ceramic core cavity, then using the ceramic core to press the wax, and then carrying out the tree assembling, shell making, dewaxing, baking and cotton wrapping process, finally pouring, the ceramic core cavity is filled with silica sol filler, which can effectively reduce the heat storage capacity of the ceramic core, thereby accelerating the cooling of the ceramic core after pouring, thereby solving the problem of surface loose defect of the hollow blade casting, and the qualified rate of the casting can be improved by 20%-30%.

[0054] Finally, it should be explained that the above specific embodiments are only used to illustrate the technical solutions of the application and are not limited, although the application is described in detail with reference to the examples, those skilled in the art should understand that the technical solutions of the application can be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the application, which should be covered in the scope of the claims of the application.

Claims

1. A method for eliminating surface porosity in hollow blade castings, characterized in that: Includes the following steps: S1. Prepare silica sol filler, and use a dropper to drip the prepared silica sol filler into the cavity of the ceramic core, and dry it to obtain a ceramic core with filler; S2. Place the ceramic core with filler into the single-blade wax mold, and inject medium-temperature wax into the single-blade wax mold using a wax press to press out the blade wax mold with ceramic core. S3. Adhere the blade wax model to the gating system with adhesive wax, and then use a hot knife to heat the single blade wax model and combine it with the gating system. S4. The single-blade wax model combined in step S3 is used to make a shell, and then the shell is dewaxed to obtain the blade mold shell. S5. Firing the blade mold shell and then cooling it before wrapping it with high-temperature resistant ceramic cotton. S6. Preheat the mold shell from step S5, melt the master alloy and pour it into the mold shell. After pouring the alloy, cool it under vacuum in the furnace for 5-60 minutes to obtain the casting. Remove the casting from the mold shell chamber and cool it. S8. Remove the gating gates and risers from the casting, and remove the ceramic core using a core-removing kettle; S9. Inspect the casting from step S8. After passing the inspection, the hollow blade casting is obtained. By mass percentage, the silica sol filler in step S1 comprises 70%-75% zircon sand, 18%-27% silica sol, and 3%-7% cobalt aluminate.

2. The method for eliminating surface porosity in hollow blade castings as described in claim 1, characterized in that: In step S2, the injection temperature is 70-80℃ and the injection pressure is 5-10 bar.

3. The method for eliminating surface porosity in hollow blade castings as described in claim 1, characterized in that: In step S4, the dewaxing temperature of the mold shell is 150-180℃, the dewaxing time is 10-20 minutes, and the dewaxing pressure is 5-10 bar.

4. The method for eliminating surface porosity in hollow blade castings as described in claim 1, characterized in that: In step S5, the roasting temperature is 800-1000℃ and the roasting time is 8-12h.

5. The method for eliminating surface porosity in hollow blade castings as described in claim 1, characterized in that: In step S6, the preheating temperature is 900-1200℃ and the preheating time is 8-12h.

6. The method for eliminating surface porosity in hollow blade castings as described in claim 1, characterized in that: In step S6, the master alloy is K447A or K452, and the melting temperature of the master alloy is 1400-1550℃.

7. The method for eliminating surface porosity in hollow blade castings as described in claim 1, characterized in that: In step S6, the vacuum level is ≤0.01 Pa.