| The mechanical properties of extruded bar, which was made of Fe-4.1, 4.7 and 4.9 wt%C alloy powders, were investigated in relation to the size, volume fraction of primary cementite and of eutectic cementite and distribution of temper carbon. Since the content of temper carbon generated from cementite increases as the size of primary cementite decreases, the tensile strength of extruded bar was deteriorated from 852MPa to 739MPa. The yield strengths of extruded bars are 392, 549, 528MPa and its their elongations are 4.4, 1.0, 0.8% when they contain 4.1, 4.7, 4.9 wt%C, restpectively. The yield strength improvement of hypereutectic extruded bar compared to hypoeutectic extruded bar is due to the larger volume fraction of cementite. Considering the hypereutectic extruded bar, the decreased yield strength of extruded bar with 4.9 wt%C is explained by the content and irregular distribtuion of temper carbon. |
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