Department of Mechanical and Control Engineering,Tokyo Institute of Technology, Tokyo, Japan

More than twenty five (25) types of high-carbon iron alloys are used for production of rolls with consecutive content of basic elements: C – 2,6…3,8 %; Si – 0,2…2,0 %; Mn – 0,2…1,2 %; Cr – 0,1…20,0 %; Ni ≤ 0,15…4,2 %; V – 0…0,8 %; Cu – 0…1,0 %; Ti – 0…0,05 %; Mo – 0…1,0 %; Ce – 0…0,085 %; N ≤ 0,03…0,04 %; S ≤ 0,05…0,1 %; P ≤ 0,04…0,4 %. The structure of these cast irons usually includes 2-4 phases (troostite, bainite, needled martensite, austenite, graphite). The main objective of this investigation is to analyze peculiarities of structure of alloy cast iron mill rolls working layer, which is produced by centrifugal casting and its influence on processibility with grinding. The process of chip forming was studied on basis of experimental examination of chips morphology and their dispersed composition. The major phase component of roll cast iron is carbide. The quantity, morphology, composition and structure of rolls define running ability and chip forming. The chip particles of highchrome cast iron have narrower breakup mainly 50-63 μm and for chrome-nickel cast iron, the main fractions are 63-100 and 100-200 μm. The content of carbides at highchrome cast iron chip particles could be about 50 %. These chip particles can be used as raw materials base in the cast iron roll production and to develop new inexpensive powders for thermal spraying of wear resistant coatings and other purposes. The main properties of such powders like particles size, shape, composition, structure, technological fluidity and bulk density were studied.

کلیدواژه ها:

Alloyed cast iron ، alloyed carbides ، chilling layer ، forming rolls ، chip ، powder