| The susceptibility to temper embrittlement for Ni-Cr steel of various structures has been studied, and following results were obained. 1. The microstructures studied were martensite, bainite and martensite and pearlite which were obtained by means of quenching and isothermal transformations. The transition temperatures of the embrittled steels showed a trend of shift to higher temperature than that of unembrittled steels in all structures, and the shifted temperatures were 82℃ in martensite, 42℃ in bainite and martensite mixture and 28℃ in pearlite steel respectively. 2. The observed transition temperatures for unembrittled steels were -84℃ in martensite, -54℃ in bainite and martensite mixture and -22℃ in pearlite steel. However in the case of embrittled steels the transition temperatures turned out to be near same in all structures. The reason for this is considered that the observed transition temperatures could result from the combined effect of various factors on the impact properties of these embrittled steels. 3. Hardness was not effected on embrittleness of Ni-Cr steel. |
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