As-cast high pearlite quantity and high vermicular rate vermicular graphite cast iron and preparation method thereof

Abstract

The invention discloses as-cast high pearlite quantity and high vermicular rate vermicular graphite cast iron and a preparation method thereof. The vermicular graphite cast iron is prepared from the following components by weight percent: 3.5-3.8% of C, 2.2-2.4% of Si, 0.8-1% of Mn, 0.2-0.4% of Cu, 0-0.4% of Mo, 0.08-0.1% of Sn, 0.2-0.4% of Cr, 0.2-0.5% of Ni, 0.05-0.1% of Nb, less than or equal to 0.06% of S, less than or equal to 0 .06% of P, and the balance of Fe and impurities introduced by raw materials. The vermicular graphite cast iron with a high creep rate (90-98%) is obtained by using an Mg-RE creeping method for controlling; furthermore, by means of micro-regulation of multiple alloy elements, the vermicular graphite cast iron with a high high pearlite quantity (90%-100%) can bestably obtained; the tensile strength of the vermicular graphite cast iron is greater than or equal to 500MPa, the elongation of the vermicular graphite cast iron is greater than or equal to 1.5%, Brinell hardness of the vermicular graphite cast iron is 230-260HBW, and the microhardness of pearlite is 300-320HV. The vermicular graphite cast iron provided by the invention has the characteristics of being good in mechanical properties, thermal fatigue resistance, thermal crack resistance and wear resistance under the extremely harsh working conditions; the preparation method is simple in control method and can stably produce castings with excellent comprehensive performance, thus being suitable for industrial mass production.

Description

technical field [0001] The invention belongs to the field of metal materials, and relates to a preparation method of vermicular graphite cast iron with high pearlite content and high creep rate in the as-cast state. Background technique [0002] Brake drums of heavy-duty trucks, high-load internal combustion engine cylinder blocks and cylinder liners and other components are subjected to strong friction, high thermal loads, and huge temperature gradients during service, and their service conditions are extremely harsh. The strength of materials for such components , Wear resistance, heat resistance and thermal fatigue resistance put forward higher requirements. At present, a material with excellent comprehensive performance - compacted graphite cast iron has been widely researched and applied, especially the compacted graphite cast iron with high pearlite content and high creep rate, which has good casting performance, compactness and better casting performance. Mechanical ...

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Problems solved by technology

[0005] The purpose of this invention is to provide a kind of preparation method of as-cast vermicular graphite cast iron with high pearlite content and high creep rate, so as to overcome the problems such as brake drums of existing heavy-duty trucks, high-load internal combustion engine cylinder blocks and cylinder liners. The problem of damage and failure due to insufficient heat resistance, thermal fatigue resistance, wear resistance, and deformation resistance during service

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