This paper overviewed the research results, including mulling effect on the properties of green sand and on the qualities of green sand molds. Effect of accumulated mulling time on the relation of compactibity and moisture absorption of green sand was discussed. Such effect on the variation of green and dry strength, friability and permeability of green sand for a given compactibility (40-45%) was also included and discussed. Experimental data illustrated that green sand with a long accumulated mulling time developed a great toughness, when a sand specimen was subjected to a compressive load, prior to fracture. This improved toughness decreased the draft needed for making a sound cylindrical cavity in the sand mold.
展开▼
