Microstructure Evolution and Mechanical Hardening of Eutectoid Steel During Cold-rolling

doi:10.3901/JME.2018.16.086

Abstract

Abstract: In order to make more efficient use of the ultra-fine lamellar structure of sorbite to improve the mechanicalproperties of steel, the microstructure evolution of patenting Fe-0.8C steel with various amounts of rolling(from 10-90% reduction) are studied by TEM and EBSD etc. Combing with the tensile test, the strengthening mechanism of the steel is revealed by investigating with the relationship between microstructure changes and mechanical properties caused by different cold rolling reduction.The results showed that the interlamellar spacing(ILS) is gradually decreased with increasing of cold-rolled reduction and is refined to 57 nm at 90% reduction. The local plastic strain (KAM value) caused by cold rolling is rapidly increasing at low strain and reached its peak at 70% reduction. It is observed that the dislocations located in the lamellar ferrite are mainly concentrated in the rolling process and increased with increasing of cold-rolled reduction. The tensile strength of cold-rolled specimens increased with rolling reduction, and the strengthening mechanism is in accordance with the interface strengthening model. After 90% cold-rolled reduction, the tensile strength over 2300 MPa is achieved. It provides a new idea for the development of high strength steel.

Key words: cold-rolling, eutectoid steel, high strength steel, strengthening mechanism

CLC Number:

TG142

YANG Caiding, LIU Ye. Microstructure Evolution and Mechanical Hardening of Eutectoid Steel During Cold-rolling[J]. Journal of Mechanical Engineering, 2018, 54(16): 86-92.

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