【摘 要】
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The microstructure and mechanical properties of an HB400 grade abrasion resistant steel was studied with an emphasis on the initial microstructure before in
【机 构】
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Institute of Research of Iron and Steel(IRIS)of Sha-steel,Zhangjiagang,Jiangsu,215625,China
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The microstructure and mechanical properties of an HB400 grade abrasion resistant steel was studied with an emphasis on the initial microstructure before intercritical heat treatment.The result shows that the initial microstructure,before intercritical quenching(Q),has a great effect on the final microstructure and mechanical properties.The hardness of samples with two initial microstructures,i.e.bainite and martensite,is almost the same,but the toughness and wear resistance of the latter are much higher than that of the former,after intercritical quenching plus tempering(Q+T)process.The one with bainite as the initial microstructure has a final microstructure of block-type tempered martensite and ferrite with martensite islands inside.Cracks may easily occur at the boundaries of martensite islands and pass through the low angle grain boundaries in the ferrite.By contrast,the one with martensite as the initial microstructure has a uniformly distributed tempered martensite and needle-like ferrite.The boundaries between them are high angle grain boundaries,and hence cracks may be arrested or deflected,resulting in a higher toughness.
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