Nail-like-graphite-free nodular cast iron for wind power equipment and preparation method thereof

Abstract

The invention belongs to the field of nodular cast iron casting, and relates to nail-like-graphite-free nodular cast iron for wind power equipment and a preparation method thereof. By optimizing the component content of the nodular cast iron, intake of harmful elements is reduced, the carbon content is strictly controlled in the eutectic period, after a large number of silicon solid solutions are formed, dissolution of carbon in hexagonal lattices is accelerated, and precipitation of a large number of carbon on the grain boundary is prevented. At the moment, anti-nodulizing segregation elements with a high content exist on the grain boundary, and the diffusion and accumulation of carbon to a nucleation substance from different directions are prevented from being blocked, so that graphite is balled, and nail-like graphite is prevented from being formed. In the preparation process of the nodular cast iron, the pouring temperature, the mold filling speed and the heat preservation time are strictly controlled, segregation of anti-nodulizing elements is reduced, the forming probability of the nail-like graphite is reduced again, and the physical performance of the cast iron is guaranteed to a certain degree.

Description

technical field [0001] The invention belongs to the field of nodular cast iron casting, and relates to a nodular graphite-free nodular graphite cast iron for wind power equipment and a preparation method thereof. Background technique [0002] Ductile iron is an important part of national economic development, mainly used in wind power, nuclear power, automobile industry, etc. Wind power is mainly made of ferritic ductile iron, such as QT400-18AL, QT350-22AL, QT450-18AL, QT500-14, QT600-10, etc. The representative castings of nuclear power include nuclear waste storage and transportation tanks, which are mainly used to store nuclear waste , representing the brand QT400-18AL; the automotive industry produces more small products, mainly high-grade products, such as QT600-3, QT700-2, etc., representing the castings with engine crankshafts. Whether it is low-grade or high-grade ductile iron, whether it is ferritic ductile iron or pearlitic ductile iron, in addition to paying att...

AI Technical Summary

Problems solved by technology

[0003] Nail-shaped graphite mostly appears on ductile iron parts. Grades above QT400 are more common. Nail-shaped graphite is also called water-grass-like graphite. The shape of graphite is like a random superposition of iron nails. The elongation of the body will deteriorate sharply, and the local mechanical properties of the casting will deteriorate. When the casting is repeatedly loaded during the service stage, it is equivalent to testing the fatigue strength of the casting. When the surface quality of the casting is weak, microscopic cracks occur, and the cracks continue to expand over time. , when the crack extends to the nail-shaped graphite area, the crack will expand rapidly, resulting in macroscopic cracks, and even cause the casting to break, bringing economic losses to the machine manufacturer

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