Effect of Ce on the High Temperature Oxidation and Hot Cracking Behavior of Copper-arsenic Steel
The effect of Ce content on high temperature oxidation of steel containing copper-arsenic and the inhibition of hot cracking was investigated by thermogravimetry,optical microscope(OM),scanning electron microscope(SEM)and Gleeble-3800 thermal/mechanical simulation machine.The oxidation kinetics analysis and oxide scale morphology observation shows that the oxidation weight gain gradually decreases with the increase of Ce content.Furthermore,oxidation kinetics follows the initial linear oxidation law and the later parabolic oxidation law at 950 ℃ to 1050 ℃,while oxidation kinetics obeys linear oxidation law of two stages at 1100 ℃ and 1150 ℃.The oxidation activation energy increases as increasing Ce content,which results in the oxidation resistance improvement of steel.The results of element mapping distribution and hot compression test indicates that the copper-arsenic enrichment degree of the steel without Ce is maximum at 1050 ℃ along with the penetration of copper-arsenic enriched liquid phase into the grain boundary,and meanwhile the hot cracking is the most serious.However,the copper-arsenic enrichment at the scale/steel matrix interface effectively is reduced and the hot cracking of steel caused by copper-arsenic enriched liquid phase is suppressed with the increase of Ce content.The increase of oxidation activation ener-gy,the formation of Fe2SiO4 layer and arsenic-containing rare-earth inclusions are the reasons of the improvement of hot crack-ing of steel containing copper-arsenic by rare-earth Ce.
Cecopper-arsenic steelhigh temperature oxidationoxide layerenrichmentinclusions
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