Microstructure and Mechanical Properties of Cooled and Tempered Cu and Nb-Bearing Ultra-Low Carbon Steels

Abstract:

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To improve the toughness and weldability, the carbon content of the steels has to be deduced, and more and more attention has been attracted to the low carbon and ultra-low carbon steels. To strengthen the microstructure Cu and Nb-bearing steels are developed. However, the knowledge on influence of combined addition of Cu and Nb is still in lack. The microstructure and mechanical properties are studied in the 6-mm thick as-rolled and tempered ultra-low carbon steel plates with varied copper and niobium content. The microstructure and mechanical properties are studied in the 6-mm thick as-rolled and tempered ultra-low carbon steel plates with varied copper and niobium content. The experimental results show that if niobium is added without copper, the increase of niobium addition does not have a significant influence on the phase transformation and mechanical properties before tempering. The strength and toughness of those copper-free niobium steels do not vary significantly after tempered at different temperatures, while the strength of niobium steels with 1.8% copper added increases after tempered in the range of 450-650°C and reaches a peak at 500-550°C. If combined with 1.8% copper, the increase of niobium addition from 0.08% to 0.16% improves the hardenabililty and strength significantly, and the strength peak after tempering moves to a lower temperature. The strength of air-cooled niobium steels with 1.8% copper added is usually higher than those water-cooled, while after tempered at a proper temperature, the strength of the latter becomes higher than the former.

Info:

Periodical:

Materials Science Forum (Volumes 638-642)

Main Theme:

Edited by:

T. Chandra, N. Wanderka, W. Reimers , M. Ionescu

Pages:

3242-3247

DOI:

10.4028/www.scientific.net/MSF.638-642.3242

Citation:

H. Guo et al., "Microstructure and Mechanical Properties of Cooled and Tempered Cu and Nb-Bearing Ultra-Low Carbon Steels", Materials Science Forum, Vols. 638-642, pp. 3242-3247, 2010

Online since:

January 2010

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Price:

$35.00

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