不同基体组织的蠕墨铸铁热疲劳性能的研究

Thermal Fatigue Properties of Vermicular Cast Irons with Different Matrix Structures

采用板状带V型缺口的试样,研究了蠕墨铸铁的基体组织对其热疲劳性能的影响。结果表明,当热循环温度的上限超过珠光体相组织变化温度时,蠕墨铸铁的热疲劳性能随基体组织中珠光体量的增加而下降;相反,当热循环温度的上限低于珠光体相组织变化温度时,稳定的珠光体组织可以有效地阻止热疲劳裂纹的扩展,蠕墨铸铁的热疲劳性能会随基体组织中珠光体量的增加而增强。

By using V-notched and plate-shaped specimens,the influences o f matrix structures on the thermal fatigue properties of vermicular irons were i nvestigated.In case of the upper limit of the cy-cling temperature being highe r than the phase transition temperature of pearlite,the thermal fatigue re-sis tance of vermicular iron decreased with increase of pearlite amount.On the cont rary,in case of the upper limit of the cycling temperature being lower than the phase transition temperature of pearlite,the stable pearlite structure could r estrain the thermal fatigue crack propagation so efficiently that the ther-mal fatigue resistance of vermicular iron increased with increase of pearlite amount of the matrix.