0Cr15Ni25Ti2Al堆焊层热疲劳性能

Thermal fatigue performance of 0Cr15Ni25Ti2Al welding cladding

采用激光重熔工艺处理0Cr15Ni25Ti2Al堆焊层表面,研究不同激光重熔工艺参数对堆焊层的显微组织和热疲劳性能的影响。结果表明:经过激光重熔处理后,堆焊层表面的晶粒得到明显细化并产生固溶强化作用。相比于原始堆焊层,经过400次热循环后,选用较小的激光功率进行激光重熔处理后的表面,其热疲劳裂纹的萌生周期较长,裂纹在传播过程中具有较小的增长速率。选用较大的激光功率进行激光重熔处理后,其裂纹萌生周期较短,但裂纹的增长速率依然小于原始堆焊层。观察1000次热循环后,不同激光参数处理后表面裂纹形貌,可知出现上述现象主要是由于经过激光重熔处理后,堆焊层表面组织产生细晶强化、固溶强化以及沉淀强化而引起的。

Laser remehing process is adopted for OcrlSni25ti2al hardfacing layer surface processing, to study the different laser remelting process parameters on the effect of the microstructure of surfacing layer and thermal fatigue performance. The results show that the grains on original welding cladding are refined and generate solution strengthening effect ＇after laser surface remehing. Comparing with original welding cladding, ＇after 400 times thermal cycle, the initiation period of thermal fatigue crack on the surface treated by laser remehing with lower laser power is longer and the growth rate of thermal fatigue crack is slower. While using higher laser power,the thermal fatigue crack has shorter initiation period while the growth rate is still slower. The morphology of thermal fatigue crack after 1000 times thermal cycle with different laser parameters shows that the grain refining,solution strengthening and precipitation strengthening of welding cladding after laser surface remelting treatment result in above phenomenon.