The type and size distribution of inclusion on G50 steel smelted by different metallurgy processes have been analyzed by SEM,EDAX.Results have indicated that tensile and yield strength are mainly affected by microstructure regardless of type and morphology of inclusions.Cohesion between NbCN and matrix is much bigger than that of between MnS and matrix.During plastic fracture,crack propagation is manipulated by the mechanism of competition in the inclusion of different type and morphology.It firstly appears in the site of inclusions which have both the poor cohesion with matrix and the shape of stress concentration,then at the inclusions with strong cohesion with matrix and stress concentration.
Key words
ultra-high Strength /
inclusion /
plastic properties
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Footnotes
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