JPH05228611A - Method for inspecting remained core in precision casting - Google Patents

Abstract

PURPOSE:To provide the method for inspecting remained core in a precision casting, by which the remained core in insoluble state can smoothly and surely be detected and a stable product having good quality can be obtd. CONSTITUTION:By utilizing the difference of X-ray transmissivity between a low X-ray transmissive liquid material filled into a hollow part 3a of a casting product 3 formed with core dissolution and a core, the existence of the remained core 1a is inspected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precision casting method (a brazing method) such as a lost wax method, and more particularly to an inspection method after casting a product having a hollow portion.

[0002]

2. Description of the Related Art The wax casting method is advantageous in that it is easy to mass-produce complex three-dimensional shapes and has high dimensional accuracy and few internal defects. It is widely used to manufacture mechanical parts that are difficult to manufacture by machining.

By the way, in a mechanical part such as a turbine blade cast by the above-mentioned brazing die casting method, a hollow part may be provided inside the part in order to increase the cooling capacity and reduce the weight. In the case where this hollow portion is manufactured by the above wax casting method, conventionally, there is known a method of embedding a ceramic core in a molded product formed by brazing or the like and performing casting. The basic steps will be briefly described.

In order to cast a thin hollow component by the brazing mold casting method, first, a core is formed corresponding to the shape of the hollow portion of the component to be cast using ceramics such as fused silica as a raw material.

Next, the core is assembled inside a mold in which a void having the same shape as the outer surface contour of the component to be cast is formed. Then, a melted material such as a brazing material is injected into the voids through a flow path formed in the mold to form a molded product in which the core is embedded (molding step).

A plurality of molded products molded as described above are assembled in a dendritic form, and a ceramic layer is coated around the assembly by an investment method or a ceramic shell molding method to form a model (coating step). Then, the molded product embedded in the model is eluted while leaving the above core (dewaxing step), and then the model is
Baking at a temperature of around 000 ℃ removes the organic components remaining inside, and then elutes the molded product to create a model (mold).
Molten metal is poured into the voids formed inside (casting process).

After pouring the molten metal, after waiting for the molten metal to cool, the mold is dropped to take out a casting tree in a dendritic form, and the casting tree is cut off so that the external contour is the same as the predetermined part shape, Obtain a cast product in which a core is cast. Then, by immersing the cast product in an alkaline solution to dissolve the core, a hollow portion having a predetermined shape is formed in the cast product.

[0008]

However, when a cast product having a hollow portion is manufactured as described above,
The ceramic core may not be completely melted and may remain in the corner of the hollow portion, etc., and if the hollow portion has a complicated shape, it was difficult to find it from the outside during inspection. ..

The present invention has been made in view of the above circumstances, and its object is to enable smooth and reliable detection of a core that remains undissolved, which is of good quality and stable. To provide a method for inspecting a core residue in precision casting capable of obtaining a finished product.

[0010]

In order to achieve the above object, the present invention forms a molded product having the same shape as the product by embedding a core, coating the molded product, and then molding the molded product. Replace the product with metal and cast it,
In a precision casting method for producing a product by melting the core, after melting the core, the hollow portion formed in the product by melting the core is filled with a liquid material having a low X-ray transmittance. In this state, product inspection by X-ray is performed.

[0011]

In the method for inspecting the core residue in the precision casting of the present invention, the difference in the X-ray transmittance between the liquid and the core filled in the hollow portion of the product having a low X-ray transmittance is utilized. , Inspect for residual cores.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 shows a molded product 2 formed by inserting a ceramic core 1 into a cavity in an injection molding die and injecting a molten wax (wax) into the molding (insert molding). .. Then, after forming the molded product 2 including the core 1 configured as described above, the process proceeds to the coating step. That is, a model is formed by repeating the operation of adhering the binder slurry to the outer surface of the molded product 2 and further sprinkling the refractory particles.

Next, after the model is dried, a dewaxing process is performed, and the molded product 2 embedded in the model is eluted while leaving the core 1. Then, after firing the above model to remove the organic components remaining inside, the model (template)
The molten metal is poured into the voids formed inside, the cooling of the molten metal is awaited, the mold is dropped, the casting tree in a dendritic form is taken out, and the casting tree is cut off, so that the core 1 is cast inside. Get a cast product. Then, this casting is immersed in an alkaline solution to dissolve the core 1 to obtain a casting (turbine blade) 3 having a hollow portion 3a having a predetermined shape.

Subsequently, a residual inspection of the core 1 of the cast product 3 is performed. That is, the hollow portion 3a of the cast product 3 has 5 to 2
With 0% by weight of barium sulfate filled, X-rays are irradiated to inspect whether or not a part of the core 1 remains inside the hollow portion 3a. At this time, when a part of the core 1 remains in the hollow portion 3a, as shown in FIG. 2, the core-remaining part 1a is more likely to transmit X-rays than other parts. Therefore, it is possible to distinguish smoothly and surely from other parts, and it is possible to easily carry out the inspection. Further, since barium sulfate has a good suspending property, unnecessary barium sulfate can be easily removed by passing water or warm water, and can be returned to the original cast product. In the above embodiments, barium sulfate was used for description, but other heavy metals having good filling and removing properties, such as gallium oxide, may be used.

[0016]

As described above, according to the present invention, a molded product having the same shape as the product is molded by embedding a core, the molded product is coated, and then the molded product is replaced with a metal. In the precision casting method in which the core is melted to produce a product by melting the core, after melting the core, the X-ray transmittance is low in the hollow portion formed in the product by the core melting. Since the product inspection by X-ray is performed in the state filled with the liquid substance, the difference in the X-ray transmittance between the liquid substance having a low X-ray transmittance filled in the hollow part of the product and the core is used. Then, by inspecting the presence or absence of the remaining cores, the cores remaining undissolved can be smoothly and surely detected, and a product of good quality and stable can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view of a molded product showing an embodiment of the present invention.

FIG. 2 is an explanatory view of a cast product showing an embodiment of the present invention.

[Explanation of symbols]

 1 Core 1a Core Remaining Part 2 Molded Product 3 Cast Product (Turbine Blade) 3a Hollow Part

Claims (1)

[Claims] 1. A molded product having the same shape as that of the product is molded by embedding a core, the molded product is coated, and then the molded product is cast by replacing it with a metal.
In a precision casting method for producing a product by melting the core, after melting the core, the hollow portion formed in the product by melting the core is filled with a liquid material having a low X-ray transmittance. A core residual inspection method in precision casting, characterized by performing product inspection by X-ray in the state.