ОПТИМИЗАЦИЯ ТЕХНОЛОГИИ ИЗГОТОВЛЕНИЯ ЦЕНТРОБЕЖНОЛИТЫХ ВАЛКОВ

Abstract

This paper reports the sheet roll spun casting. It is shown that sheet rolls of required quality and with minimum production costs are manufactured through a method of spun casting on a machine with a vertical axis of a mould rotation. It is defined that at spun casting a more intensive foundry cooling occurs as a result of which a blank is characterized with a denser and more even structure of a working layer. It is revealed that the stability of such a process depends to a considerable degree upon a spin casting system functioning a significant property of which is a speed of rotation. In the paper there is analyzed a rotation speed influence upon a grain size, a quantitative ratio of structural constituents in a working layer composed of nickel-chromium cast iron and also upon the level of its properties. The analysis of the rotation speed influence of a casting mold upon a structure and a property level of a roll working surface was based on experimental investigations of foundries under industrial conditions. The microstructure (the size of primary grains, their composition) of products analyzed was estimated with the aid of a common metallographic procedure. On the basis of experiments carried out it is determined that even an insignificant increase (by 7%) of mould rotation speed during roll casting allows without expensive processing of liquid melt of a work-ing layer increasing its structure uniformity. As a result of this the level of its properties increases (hardness – by 3 units). Consequently, the increase of rolling tool efficiency is expected. The presented results of investigations are basic for works on servicing characteristics increase of spin-cast rolls.