METHOD FOR MOLDING ROLLERS Russian patent published in 1997 - IPC

FIELD: foundry. SUBSTANCE: rollers, when being operated, constantly experience variable loading, wear, and temperature oscillations. So roller metal must possess sufficient strength, plasticity, heat and wear resistance with low residual stress after casting. Large number of deteriorations in working layer of rollers gives rise to enormous loss at roller making and foundry enterprises. Great part of it is caused by poor technology of mold and methods of filling the mold, which are not in conformance with known foundry principles. Invention is aimed at replacing existing technologies involving entering metal into mold from below with new ones involving filling the mold from above. In this case, to form wear-resistant working chill layer on the barrel surface, mold is filled with grey cast iron having reduced silicon content (0.4-0.6%), and plastic properties in regions of neck and middle part of roller are provided by using globular graphite and increasing silicon content to 1.5-2.0% with sulfur content being 0.02% and magnesium residual content 0.05-0.07%. The latter is achieved by treating metal being poured with pure magnesium and ferrosilicon disposed in space of a tube suspended on the bottom of pouring basin. EFFECT: simplified process, safe introduction of magnesium into cast iron, considerably reduced amount of under- grade product and cost.