铸铁材料高温拉伸性能试验研究

Experimental Study on High Temperature Tensile Properties of Cast Iron

对几种具有不同石墨形态、不同基体组织的铸铁材料的高温拉伸性能进行了试验研究。通过大量的试验,得出以下结论:(1)HT280、RuT400、QT400-15的抗拉强度均随温度升高而下降,且变化趋势一致,拐点均在400℃左右,石墨形态和基体组织共同交互作用影响抗拉强度的下降幅度;(2)HT280、RuT400、QT400-15的弹性模量随温度升高降低,QT400-15材料的弹性模量随温度的升高而逐渐下降,在450℃以后显著降低,逐渐低于珠光体基体为主的蠕墨铸铁,但高于灰铸铁;(3)在基体组织相同的情况下,蠕虫状石墨的铸铁比片状石墨的灰铸铁具有更高的高温抗拉强度,且蠕墨铸铁随蠕化率的降低,高温力学性能升高。

The high temperature tensile properties of cast iron materials with different graphite forms and different matrix structures were studied. Through a large number of tests,the following conclusions were drawn： （ 1 ）The tensile strength of HT280,RuT400 and QT400-15 decreased with temperature,and the change trend was the same. All three inflection points were about 400℃.（2）The elastic modulus of HT280,RuT400 and QT400-15 decreased with the temperature. The elastic modulus of QT400-15 decreased gradually with temperature,and it decreased significantly after 450 ℃,which was lower than that of vermicular iron but higher than the gray cast iron.（3）In the case of the same matrix,the vermicular iron had higher high-temperature tensile strength than gray cast iron ,and the high temperature mechanical properties were improved with the decrease of vermicnlar rate.