在不同温度下球墨鑄铁的冲击性能

本文描述高温冲击实验的技术,以及由-85℃至1070℃的铸态和锻造后的球墨铸铁的冲击性能。研究结果找到了基体主要为铁素体的球墨铸铁的两个变脆温度范围(-20℃以下和550℃至700℃之间)和一个比较具有韧性的温度范围(850℃与1050℃之间)。在这些温度范围内,曾考查试样的断口情况和断裂时的弯曲角度,并与其基体组织的变化相联系,进行讨论。最后,本文指出研究结果在球墨铸铁的应用上所起的作用,以及在球墨铸铁热加工时对于选择热加工温度的意义。

THE IMPACT PROPERTIES OF NODULAR CAST IRON AT VARIOUS TEMPERATURES

Impact tests have been carried out on nodular cast iron in -the cast and forged conditions from -85℃ to 1070℃. The results indicate that nodular cast iron of predominantly ferritic matrix possesses two brittle temperature ranges (below 20℃ and between 550 and 700℃), and one comparatively more ductile range (between 850℃ and 1050℃).The fractures and the bending of the specimens at fracture have also been examined, and these have been correlated to the changes in structure of the matrix in the discussion.Finally, a brief account has been made of the possible applications of the results in the present research in evaluating the applicability of nodular cast iron at various temperatures; and, in particular, in the choice of proper hot working temperatures of this new material. The best hot working temperatures as indicated by the present results have been confirmed by actual forging and upsetting tests under the pneumatic and drop hammers respectively.