| 摘要 |
THE PRESENT INVENTION IS AIMED AT PROVIDING A CASTING METAL MOLD WHICH DOES NOT REQUIRE THE HEAT TREATMENT OF THE PRODUCT AFTER THE CASTING AND WHICH IS INEXPENSIVE. ACCORDING TO THE PRESENT INVENTION, AN ORIGINAL MOLD FOR A METAL MOLD TO BE OBTAINED IS CREATED FROM CAST IRON, AND THE ORIGINAL MOLD IS HEATED TO A PREDETERMINED TEMPERATURE TO DECARBURIZE ONLY ITS SURFACE LAYER. SUBSEQUENTLY, THE ORIGINAL MOLD IS HEATED TO ANOTHER PREDETERMINED TEMPERATURE TO MELT ONLY THE INNER, LOW-MELTING-POINT PORTION OF THE ORIGINAL MOLD, AND THE MELTED PORTION IS MADE TO FLOW TO THE OUTSIDE. THUS, A HOLLOW CASTING METAL MOLD MADE OF CAST IRON IS PRODUCED. SINCE THE HOLLOW METAL MOLD HAS A LOWER HEAT CAPACITY THAN A SOLID METAL MOLD, THE COOLING RATE OF THE CAST PRODUCT AFTER THE CASTING IS LOWER, SO THAT THE HARDNESS OF THE CAST PRODUCT WILL BE LOWER. |
