Effect of Cooling Mode on BN Phase Morphology and Mechanical Properties of CB2 Steel

doi:10.12068/j.issn.1005-3026.2017.07.010

Abstract

Abstract: To study the effect of cooling mode on the BN phase morphology and mechanical properties of a new generation ferritic heat resistant steel， the CB2 steel with the B content of 0.012% after 1100℃ austenitizing was carried out by the air-cooling and water-cooling treatment， respectively. The results showed that the size of the BN phase in the austenitized CB2 steel reduced with the increase of cooling rate.A BN phase with 600nm size was observed in the water-cooled CB2 steel sample， associated with the increase of mechanical property.The BN phases were irregular blocks in an air-cooled sample， associated with internal cracks and fracture， while they were compact rectangles in a water-cooled one.Because the growth rate of BN nuclei increased with the increase of cooling rate and the nucleation rate of BN phase increased with the increase of supercooling degree， it was found that the refiner BN phases were dispersed in the CB2.

Key words: ferritic heat-resistant steel, CB2 steel, cooling mode, BN precipitates, microstructure

CLC Number:

TG142.73

MA Yu-lin， LIU Yue， GU Jin-tao， LIU Chun-ming. Effect of Cooling Mode on BN Phase Morphology and Mechanical Properties of CB2 Steel[J]. Journal of Northeastern University Natural Science, 2017, 38(7): 955-959.

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