Preparation technology for nodular cast iron with TRIP (transformation-induced plasticity) effect

Abstract

The invention relates to a preparation technology for nodular cast iron with a TRIP (transformation-induced plasticity) effect. The preparation technology can be used for producing a nodular cast iron part, of which the strength of extension is greater than 700MPa, the elongation is 8%, and the product of strength and elongation is greater than 6000MPa%. The cast tissue is a complex phase tissue of ferrite base, bainite, retained austenite, a bit of martensite and graphite, soft ferrite base endows the whole cast with good ductility, hard bainite, distributed in the ferrite base in a complex intertwining manner, serves as a skeleton so as to improve the strength of the cast, a bit of martensite is the hardest phase in the tissue and plays a role in improving the strength of the cast, furthermore, a bit of retained austenite not only improves the ductility of the cast, but also can produce a TRIP effect at room temperature. Therefore, the nodular cast iron with the TRIP effect has better comprehensive property than common isothermal quenching nodular cast iron, improves both the ductility and strength of the cast, and has higher product of strength and elongation.

Description

technical field [0001] This technology involves the preparation process of nodular cast iron with TRIP effect, which mainly involves the preparation of a high-strength, high-rigidity and high-strength ductile iron casting. After high-temperature annealing, the nodular cast iron with complete ferrite + graphite can be obtained through austria. After heat preservation in the critical zone of ferrite and ferrite, it is graded and austempered to obtain a multiphase structure of ferrite matrix + bainite + retained austenite + a small amount of martensite + graphite, which has good strength, hardness and high elongation. Background technique [0002] The appearance of ductile iron (Ductile Iron, DI for short) in the 1950s made the comprehensive performance of cast iron materials close to that of steel. It is based on its excellent performance that it has been successfully used in casting with complex stress, strength, toughness and wear resistance. Auto parts with high performance...

AI Technical Summary

Problems solved by technology

[0009] In order to ensure sufficient hardenability and prevent the formation of pearlite in the matrix structure, an appropriate amount of total elements must be added, such as Mo, Ni, and copper. The amount of these alloy elements is related to the size of the part. The more alloying elements there are, the higher the production cost will be

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