구상흑연주철의 수축결함생성에 미치는 주조방안 및 합금원소의 영향

류성곤; Sung-Kon Yu

Korean Journal of Materials Research, Vol.13, No.2, 74-80, February, 2003

DOI10.3740/MRSK.2003.13.2.074 Export Citation

구상흑연주철의 수축결함생성에 미치는 주조방안 및 합금원소의 영향

Effects of Risering Design and Alloying Element on Formation of Shrinkage Cavity in Ductile Cast Iron

류성곤^†

계명대학교 재료공학과

Sung-Kon Yu^†

Dept. of Materials Engineering, Keimyung University, Daegu, 704-701, Korea

E-mail:

The effects of risering design and alloying element on the formation of defects such as external depression, primary and secondary shrinkage cavities in ductile cast iron were investigated. Two types of risering design for the cylindrically step-wise specimen, No. 1(progressive solidification) and No. 2(directional solidification) risering designs, were prepared and six different alloy compositions were casted. In the No. 1 risering design, external depression or primary shrinkage cavities due to liquid contraction were observed in all the specimens from SG 10 to SG 60. The defects caused by liquid contraction seemed to be more affected by risering design than alloying elements. The secondary shrinkage cavities were also observed in all the specimens but a swollen surface was not observed in all the castings. The primary shrinkage cavities were located right under the top surface or connected to the top surface, and were characterized by smooth surfaces. On the other hand, the secondary shrinkage cavities were positioned in the thermal center of the specimen steps 3 and 4, and characterized by rough surfaces. In the No. 2 risering design, no external depression or primary shrinkage cavities due to liquid contraction were observed in all the specimens from SG 10 to SG 60. However, the secondary shrinkage cavities were formed in the thermal center of specimens SG 40, 50 and 60. Like the No. 1 risering design, a swollen surface was not observed in all the castings.

Keywords:external depression;shrinkage cavity;progressive and directional solidification;swollen surface

[References]

Campbell J, Castings, 2nd ed., p176, Butterworth-Heinemann Ltd, England (1993) (1993)
Agaard R, Schafer W, Hansen P, Rasmussen N, in Proceedings of the Modeling of Casting, Welding and Advanced Solidification Porcesses-IX (Aachen, Germany, August 2000). ed. Sahm P, Hansen P (RWTH, Aachen, Germany, 2000) p.861 (2000)
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[1] Campbell J, Castings, 2nd ed., p176, Butterworth-Heinemann Ltd, England (1993) (1993)

[2] Agaard R, Schafer W, Hansen P, Rasmussen N, in Proceedings of the Modeling of Casting, Welding and Advanced Solidification Porcesses-IX (Aachen, Germany, August 2000). ed. Sahm P, Hansen P (RWTH, Aachen, Germany, 2000) p.861 (2000)

[3] Fras E, Kapturkiewicz W, Wrobel Z, in Proceedings of the Modeling of Casting, Welding and Advanced Solidification Processes-VIII (San Diego, USA, June 1998). ed. Beckermann C (University of Iowa, Iowa City, USA, 1998) p.1209 (1998)

[4] Kang I, Sakaguchi T, Nakae H, in Proceedings of the 65th World Foundry Congress (Gyeongju, Korea, October 2002). ed. Hong C (Yonsei University, Korea, 2002) p.209 (2002)

[5] Yu S, Choi J, Lee J, in Proceedings of the 4th Pacific Rim International Conference on Modeling of Casting & Solidification Processes 1999 (Seoul, Korea, September 1999). ed. Hong C (Yonsei University, Korea, 2002) p.447 (2002)

[6] Li W, Liu B, in Proceedings of the 3rd Pacific Rim International Conference on Modeling of Casting & Solidification Processes 1996 (Beijing, China, December, 1996). ed. Liu B (Tsinghua University, China, 1996) p.365 (1996)

[7] Wu C, Lei T, Su K, in Proceedings of the 1st Pacific Rim International Conference on Modeling of Casting & Solidification Processes 1991 (Seoul, Korea, October, 1991). ed. Hong C(Yonsei University, Korea, 1991) p.285 (1991)

[8] Anzai K, Niyama E, Watanabe N, in Proceedings of the 5th Asian Foundry Congress (Nanjing, China, September, 1997). ed. Sun G (Southeast University, China, 1997) p.211 (1997)

[9] Liu B, Li J, Wang C, in Proceedings of the 2nd Asian Foundry Congress (Kitakyushu, Japan, October, 1994). ed. Ogi K (Kyushu University, Japan, 1994) p.381 (1994)

[10] Campbell J, in Proceedings of the 4th Asian Foundry Congress (Queensland, Australia, October, 1996). ed. Lakeland D (Queensland University, Australia, 1996) p. 33 (1996)

[11] Karsay SI, Ductile Iron Production Practices, p. 111, AFS Publication, Des Plaines, USA (1985) (1985)

[12] Karsay SI, Ductile Iron Gating and Risering, p.85, QIT INC., Canada (1981) (1981)