Compound inoculant used for producing D-type graphite cast iron and preparation method thereof

Abstract

The invention discloses a compound inoculant used for producing D-type graphite cast iron, which is characterized in that the weight percents of the constituents are as follows: magnesium 1.0-4.0, rare earth 4.0-8.0, titanium 4.0-9.0, aluminum 1.5-3.0, stibium 0.5-2.0, calcium 2.0-5.0, barium 1.0-4.0, silicon 35-50 and the balance of iron. When the compound inoculant is employed to carry out inoculation on the melted iron with high carbon equivalent, the obtained graphite in the cast iron is the D-type graphite. The mechanical properties of castings are high, the tensile strength reaches over250MPa and the compactness is good. The melted iron has high carbon equivalent, thus greatly improving the casting properties of alloys, reducing the residual stress of the castings, contributing to good size stability and enhancing the machinability of the castings. The multiple compound inoculant adopts ladle bottom pouring process, namely, the compound inoculant is placed on the bottom of a ladle, then the melted iron is injected and the compound inoculant is continuously melted and absorbed in the process of melted iron injection, thereby reaching the satisfactory inoculation effect, therefore, the method is simple and the use is convenient.

Description

Composite inoculant for producing D-type graphite cast iron and preparation method thereof technical field The invention relates to an inoculant for cast iron, in particular to a composite inoculant for producing D-type graphite cast iron and a preparation method thereof. Background technique The carbon in ordinary gray cast iron generally exists in the form of flake graphite. According to its shape, flake graphite is divided into A, B, C, D, E, F and other types. The traditional point of view is that A-type graphite is evenly distributed, non-directional, and has less splitting effect on the matrix, so that cast iron has higher strength; D-type graphite is a point-like distribution between austenite dendrites without direction or small flakes of graphite, is a detrimental tissue that reduces the strength of cast iron. However, a large number of studies in recent years have shown that D-type graphite cast iron has higher strength, denser, better dimensional stability, be...

AI Technical Summary

Problems solved by technology

However, there are many research results on which alloy elements have supercooling effect on cast iron, as well as the amount and method of addition, and some have developed intermediate alloys as inoculants, but there are not many reports on the products that have been put on the market to form products.

Images