| 摘要 |
<p>Tubular metal articles are produced by centrifugal casting in a rotary metal mold lined by centrifugally distributing a quantity of a dry finely particulate free flowing refractory material on the active mold surface with the quantity being in excess of that required for the lining, densifying the layer by rotating the mold at a rate such that the refractory layer is subjected to centrifugal force adequate to establish an equivalent specific gravity of at least 7.5, determined by multiplying the actual specific gravity of the refractory material by the number of gravities of centrifugal force, contouring the densified layer and removing the excess refractory material, rotating the mold at the casting rate and then introducing the molten metal for casting while continuing to rotate the mold at least that rate. Articles so cast have relatively smooth outer surfaces which require only finish machining. The invention employs no additives and thus eliminates the need for venting the metal mold, provides a relatively thick lining of predetermined insulating capability so as to control the grain structure of the cast metal, eliminates the usual end cores, and allows the refractory material to be recycled. The invention is particularly useful for casting articles, such as cylinder liner blanks, from grey iron, such articles having an outer enlargement, typically a transverse outer end flange. Cast according to the invention, such articles have Type A graphite throughout the entire inner surface and for at least a substantial portion of the thickness of the flange or other outer enlargement.</p> |
