Manufacturing method for cast steel products and manufacturing method for laminated structures

Abstract

To facilitate inspection and repair during the manufacturing process of cast steel products, etc., and to obtain finished products in a short time. [Solution] The method for manufacturing a cast steel product according to the present disclosure involves inserting an arm having an ultrasonic probe into the internal space of a cast steel product formed by casting, with liquid placed in at least a portion of the internal space, irradiating the inner wall surface of the cast steel product with ultrasonic waves through the liquid from the ultrasonic probe, detecting the ultrasonic echo, and determining whether or not there are defects in the cast steel product based on the echo.

Claims

1. With a liquid placed in at least a portion of the internal space of a cast steel product formed by casting, an arm having an ultrasonic probe is inserted into the internal space. Ultrasound is irradiated from the ultrasonic probe toward the inner wall surface of the cast steel product through the liquid, and the echo of the ultrasound is detected. A method for manufacturing a cast steel product, wherein the presence or absence of defects in the cast steel product is determined based on the echo.

2. Before performing the ultrasound examination, The arm with the shot nozzle attached is inserted into the internal space, A method for manufacturing a cast steel product according to claim 1, wherein the inner wall surface of the cast steel product is made to have a surface roughness suitable for inspection by injecting shot particles from the shot nozzle toward the inner wall surface of the cast steel product.

3. Before the shot blasting by the injection of the aforementioned shot particles, A method for manufacturing a cast steel product according to claim 2, comprising treating the cast steel product by a hot isostatic pressing method and performing a heat treatment.

4. Before performing the ultrasound examination, A method for manufacturing a cast steel product according to claim 1, comprising treating the cast steel product by a hot isostatic pressing method and performing a heat treatment.

5. With a cast steel product formed by casting having an internal space, and with liquid placed in at least a portion of the internal space, a person holds an ultrasonic probe by hand and inserts it into the internal space. Ultrasound is irradiated from the ultrasonic probe toward the inner wall surface of the cast steel product through the liquid, and the echo of the ultrasound is detected. A method for manufacturing a cast steel product, wherein the presence or absence of defects in the cast steel product is determined based on the echo.

6. Before performing the ultrasound examination, A person holds the shot nozzle in their hand and inserts it into the internal space. A method for manufacturing a cast steel product according to claim 5, wherein the inner wall surface of the cast steel product is made to have a surface roughness suitable for inspection by injecting shot particles from the shot nozzle toward the inner wall surface of the cast steel product.

7. Determine whether the surface roughness allows for the aforementioned inspection. A method for manufacturing a cast steel product according to claim 2 or 6, wherein if it is determined that the inspection is not possible, precision shot blasting is performed under predetermined conditions before the inspection.

8. The aforementioned predetermined conditions are: The conditions include at least one of the shot material, particle size, injection pressure, and injection time, A method for manufacturing a cast steel product according to claim 7, wherein the surface roughness is determined in advance by testing to correspond to the target value of the surface roughness.

9. The method for manufacturing a cast steel product according to claim 1 or 5, wherein the cast steel product is a valve body for an isolation valve in a nuclear power plant.

10. The method for manufacturing a cast steel product according to claim 9, wherein the inspection by irradiation of ultrasonic waves is performed after attaching a closing cover to the flow path end of the valve body and accumulating the liquid in the internal space of the valve body.

11. The method for manufacturing a cast steel product according to claim 1 or 5, wherein the liquid is water.

12. With a liquid placed in at least a portion of the internal space of a laminated structure formed by a three-dimensional molding device, an arm equipped with an ultrasonic probe is inserted into the internal space. Ultrasound is irradiated from the ultrasonic probe toward the inner wall surface of the laminated structure through the liquid, and the echo of the ultrasound is detected. A method for manufacturing a laminated structure, which determines whether or not there are defects in the laminated structure based on the echo.

13. Before performing the ultrasound examination, The arm with the shot nozzle attached is inserted into the internal space, A method for manufacturing a laminated structure according to claim 12, wherein shot particles are sprayed from the shot nozzle toward the inner wall surface of the laminated structure to make the inner wall surface rough enough to be inspected.

14. With a laminated structure formed by a three-dimensional printing device having an internal space, and with liquid placed in at least a portion of the internal space, a person holds an ultrasonic probe in their hand and inserts it into the internal space. Ultrasound is irradiated from the ultrasonic probe toward the inner wall surface of the laminated structure through the liquid, and the echo of the ultrasound is detected. A method for manufacturing a laminated structure, which determines whether or not there are defects in the laminated structure based on the echo.

15. Before performing the ultrasound examination, A person holds the shot nozzle in their hand and inserts it into the internal space. A method for manufacturing a laminated structure according to claim 14, wherein shot particles are sprayed from the shot nozzle toward the inner wall surface of the laminated structure to make the inner wall surface rough enough to be inspected.

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