摘要
针对水泥挤压辊的压缩疲劳工况,采用自行设计的双切口疲劳试样,试验了45钢母材上堆焊六种Fe-CCr-Nb合金的压缩疲劳行为.对疲劳试样表面进行原位观察和激光共聚焦裂纹分析,切口的应力应变集中促进其下方热影响区(HAZ)局部滑移线聚集并形成塑性变形区,同时在切口底部边缘萌生疲劳裂纹,穿过堆焊合金扩展进入HAZ.疲劳裂纹还在熔合线萌生并扩展,最后导致疲劳失效.试验结果表明,疲劳试样的a-N曲线近似为直线.堆焊合金基体组织主要为高硬度马氏体时,疲劳裂纹扩展速率大,疲劳寿命仅5万次;基体组织为较软的铁素体或奥氏体时,裂纹扩展速率小,疲劳寿命长达54万次.
The compression fatigue behavior of six kinds of Fe-C-Cr-Nb surfacing alloys on the base metal of 45 steel was tested with self-designed dual-notch fatigue specimens according to the compression fatigue working condition of the cement squeeze roller.In-situ observation and laser confocal crack analyses were carried out on the surface of fatigue specimens.The stress-strain concentration of the notches accelerated the accumulation of slip lines at local HAZ just below the notches and plastic deformation zones formed there.At the same time,fatigue cracks were initiated at the bottom edge of the notches and propagated into HAZ through surfacing alloys.Fatigue cracks were initiated and propagated along the fusion line as well and eventually resulted in fatigue failure.The experimental results show that the a-N curves of fatigue specimens were approximately straight lines.When the matrix micro-structures of the surfacing alloys were mainly composed of martensite with high hardness,the fatigue crack propagation rate is big and the fatigue life is only 50,000 times.While the micro-structures were composed of soft ferrite or austenite,the propagation rate is small and the fatigue life is up to 540,000 times.
作者
任振安
郑思强
黄飞
刘武慕
REN Zhen′an;ZHENG Siqiang;HUANG Fei;LIU Wumu(Jilin University,Changchun 130022,China;FAW Jiefang Automotive Co.,Ltd.,Changchun 130011,China;Northeast Electric Power University,Jilin 132012,China)
出处
《焊接学报》
EI
CAS
CSCD
北大核心
2019年第10期54-59,I0003,共7页
Transactions of The China Welding Institution
关键词
压缩疲劳
堆焊合金
微观组织
疲劳寿命
挤压辊
compression fatigue
surfacing alloy
microstructure
fatigue life
squeeze roller
