| The effects of Ni addition on the precipitation of carbides and pearlitic constituents in Hadfield steel were investigated by means of microscopy and hardness measurements. From this experiment the following results were obtained. 1) By the addition of Ni, the temperature range of precipitation of carbides became narrow, but that of pearlitic constituents was nearly unchanged. 2) Carbides were precipitated preferentially in the range of 600-700℃ and pearlitic constituents at 600℃. 3) Except the lower temperature range, carbides were precipitated in the shape of film at the grain boundaries in the earlier heating stage, but with the increase in heating time and temperature, the shape of carbides was changed as follows; acicular, granular and chain-like carbides. 4) Increased hardness was mainly affected by pearlitic constituents precipitation rather than acicular carbides. 5) With the increase in carbon contents, the pearlitic constituents precipitation rate was accelerated remarkably by the addition of Ni in Hadfield steel. |
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