球状黒鉛鋳鉄による鋼管の鋳ぐるみにおける内部空冷の効果 Effects of Internal Air Cooling in Cast-In Inserts of Steel Pipes in Ductile Cast Iron
In the insertion of pipes in casting, internal air or gas flow cooling is effective to prevent thermal damage and structural deterioration of the inserted pipe. In this report, internal air cooling was carried out for a mild steel pipe inserted in ductile cast iron. To achieve good metallurgical bonding at the interface and protection of the inserts, delayed cooling was proposed. Solidification analysis was also performed to discuss the experimental results. In the experiments with melt/insert volume ratios, VR, of 10, 30 and 100, air cooling was effective. Grain growth of the pipe structure was suppressed and the carburized zone was reduced to half in the VR 30 and VR 100 specimens. Cooling with a 100s delay had almost the same effect, with improved bonding at the interface. The calculated solidification progress and concept of liquid phase contact time, LCT, gave a good explanation of the experimental results. The internal cooling method is also effective for improving the microstructure of castings, decreasing graphite nodule size, and increasing the nodule counts markedly.
- 鋳造工学 = Journal of Japan Foundry Engineering Society
鋳造工学 = Journal of Japan Foundry Engineering Society 69(1), 35-40, 1997-01
Japan Foundry Engineering Society