The structural change in heat affected zone(HAZ)and its influence on properties of weldedwhite cast iron have been investigated by means of thermal cycle simulation technique.Thestructure of the white cast iron at peak temperature 800℃ was examined as cementite inpearlitic matrix,of which the hardness and impact toughness are the lowest,while the struc-ture after cyclic heating at high peak temperature is mainly cementite together with twinmartensite,of which the hardness and impact toughness are rather higher.The phase bounda-ries in the structure of low hardness are smooth and regular as well as with fine precipitates.Both the cleavage and interphase fracture were revealed in the structure of low hardness,whilethe transgranular fracture was found in those areas of higher hardness.
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