The Control Of Austempering Process And Properties Of ADI With Low-alloyed Cr And Mo

In this dissertation, the properties , factors, development and present pmblems of ADI are summarized. The law of austempering process and benite morphology of ADI with low- alloyed Cr and Mo are studied so as to change the present method of following the T扟T curve of steel and control its properties with the aid of the TTT curve which can provide guide in theory and technology and then realize design of the material. The study shows that the austempering temperature of ADI with low- alloyed Cr and Mo is lower (220?00 0C), the transformation curve is in the two-nosed form and the benite morphology is complicated (not only the typical B~ and BL but also nontypical and granular benite). The main properties of this kind of ADI can be controlled in the following range: ultimate tensile strength is 900?600 MPa; hardness is 48?911RC; shocking toughness is 20?0J/cm2. Therefore ,the control of the properties of ADI with low- alloyed Cr and Mo has been realized.