| 摘要 |
PURPOSE:To weld satisfactory inside and outside layers to a uniform thickness in centrifugal casting of a two-layered hollow material having a large diameter and long length with a sand mold by maintaining the casting temp. for the inside layer at a specific temp. above the eutectic temp. and maintaining the inside surface temp. of the outside layer at the specific casting speed of the inside layer at the specific value below the eutectic temp. thereof. CONSTITUTION:The casting temp. of the inside layer is maintained at the temp. higher by 140-220 deg.C than the eutectic temp. thereof in centrifugal casting of the two-layered hollow roll or pipe having the large diameter and long length with the sand mold. The inside surface temp. of the outside layer is maintained at the temp. lower by >=30 deg.C than the eutectic temp. of the outside layer when the casting speed of the inside layer is set at 5-25kg/sec. Said temp. is maintained within the range of (0.48 M2-20) deg.C when the minus difference between the eutetic temp. of the inside layer and the casting temp. of the inside layer is designated as M2. Both layers are welded in a satisfactory condition and the layer thickness uniform over the entire length is obtd. in such a case. The inside surface temp. range of the outside layer lower by 30-50 deg.C than the eutectic temp. of the outside layer is excluded if the casting speed of the inside layer is 12-25kg/sec. |
