| 摘要 |
<p>In a method of manufacturing iron castings a test wedge is cast from a molten mixture containing steel scrap and cast iron and/or pig iron, the "constitutional carbide wedge value" is determined, the molten mixture is graphitised to such a degree that a test wedge cast from the graphitised mixture shows a "processed carbide wedge value" not greater than one half of the "constitutional carbide wedge value" and not greater than one third of the thickness of the casting to be made and not less than an amount which varies as the thickness of the casting and casting the graphitised molten mixture. The "carbide wedge values" are determined by casting the molten mixture in a wedge shaped mould, breaking the wedge shaped casting lengthwise and determining the width of the line of demarkation between the white and the grey iron. The molten mixture may be graphitised by any known graphitising method as it flows from the cupola and in the preferred method the "processed carbide wedge value" should be one third of the "constitutional carbide wedge value." Since the minimum value of the ratio of the "wedge values" depends on the thickness of the casting, regard must be paid to the design of the casting to be made.</p> |
