| 摘要 |
PURPOSE:To obtain products of pearlite base in an as-cast state in the stage of casting small-sized cylinder liners by the use of a sand mold core and an outside diameter die by specifying the wall thickness of the outside diameter die. CONSTITUTION:An outside diameter die 12 having the wall thickness equal to that of a cylinder liner 10 for small-sized engines is manufactured. Said die is preheated and held, and a sand mold core 14 is set at the center thereof. Molten metal for commonly used green sand molds is charged between the die 12 and the core 14. The molten metal begins to solidify by releasing the heat of solidification to the mold 12 and the core 14. Since the molten metal in contact with the core releases the heat very slowly on account of the heat insulation of the core, the greater part of the heat possessed by the molten metal flows to the die 12, then the die heats up quickly. Thus the quick cooling of the molten metal is prevented, and pearlite base is produced approximately 100%. The die 12 is opened in about 5-10sec after the charging of the molten metal is completed, and the solidified cylinder liner is removed together with the core 14. |
