On Preparation of In Situ Composite Steel with Ultra-High Strength and its Thermal Stability

Abstract:

A new type of in-situ composite nano-multilayer plate with ultra-high strength (b 2112 MPa), Q235 steel plate with nano-layered structure of lath martensite produced by severe cold-rolling, was developed. After cold-rolling, subsequent annealing has great effect on the deformed lath morphology and grain refinement. Microstructure recrystallizing course have taken place after long time annealing at 350 °C. The recrystallization activation energy is 151 kJmol-1. Microstructure characteristics along rolling direction arrangement was decreased after annealing at 400 °C. In addition to the ultrafine ferrite grains, nano-carbides precipitated uniformly in the specimen annealed at 500 °C. Annealing at and above 600 °C resulted in coarse ferrite grains with spheroidized coarse carbides, causing grain growth. The average crystal size is about 4.7 m after annealing for 60 min at 600 °C.

• Periodical: Advanced Materials Research (Volumes 152-153)
• Pages: 436-440
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.152-153.436
• Online since: October 2010
• Authors: Jun Zhao, Han Zhang, Zhi Wang, Hong Yan Zhai, Quan Xing Wen, Min Wang, Yu Wei Gao
• Keywords: In Situ Composite Steel, Lath Martensite, Severe Cold Rolling, Thermal Stability

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