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Effects Of Several Components On The Toughness Of Deposited Metal And Usability Of Self-shielded Flux Cored Wire

Posted on:2006-04-11Degree:MasterType:Thesis
Country:ChinaCandidate:K LiFull Text:PDF
GTID:2121360155462521Subject:Materials Processing Engineering
Abstract/Summary:PDF Full Text Request
The effects of Zr, Al, RE and LiF etc on the toughness of deposited metal and usability of self-shielded flux cored wire were investigated in this paper.The experimental results show that: (1) appropriate addition of Zr, RE and LiF in flux can improve the stability of arc, but the effects of Ce-Ni alloy and mixture of rare earth elements are less than CeO2; (2) appropriate addition of Zr and CeO2 in flux can improve the appearance and overlay of slag, but excessive addition will eliminate that effects; (3) the effect of Zr on detachability is apparent, its addition should be less than 1%, the effect of CeO2 on slag detachability is not obvious; (4) appropriate addition of Zr in flux can apparently improve the low temperature toughness of deposited metal, but the increase of Al in deposited metal drastically deteriorates the toughness of deposited metal, the effect of CeO2 on toughness is not distinct. It was concluded from chemical analysis, metallographic analysis and electron microanalysis that: (1) the effect of Zr on the toughness is correlative to the composition of inclusions in the deposited metal, a certain amount of inclusions rich in Zr can increase the nucleation of acicular ferrite in deposited metal. Acicular ferrite, which is characterized by fine grain, high dislocation density in grain and large angle grain boundaries with each other, have larger resistance against crack formation and propagation, therefore has better toughness. (2) when Al in deposited metal is more than 1% , the oxygen and nitrogen content is too low, Al dissolving in γ-ferrite...
Keywords/Search Tags:self-shielded flux cored wire, low temperature toughness, microstructure, inclusion, usability
PDF Full Text Request
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