Effect of low Zr addition on microalloyed cast steel

Abstract

Zirconium is rarely used as a microalloying element, although it is used to control sulphide inclusions in as killed steels. In the present work, the effect of a 0·005 wt-%Zr addition on the microstructure and mechanical properties of a cast low carbon steel following heat treatment was examined. The Zr addition was found to increase the Charpy toughness of tempered specimens from 20·1 to 38·4 J, but no changes in toughness were observed in homogenised and quenched specimens. The hardness of tempered specimens with Zr additions was increased by 60 HV60 relative to Zr free specimens. The apparent mean grain size of the homogenised Zr free samples was 15·7 μm, compared with 11·3 μm for the specimens with Zr additions, suggesting that Zr has a refining effect on the microstructure.

Keywords

MICROALLOYED CAST STEEL ZIRCONIUM HEAT TREATMENT MICROSTRUCTURE MECHANICAL PROPERTY

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