【摘要】 模拟流体机械冲蚀与空蚀交互磨损工况,通过对比材料的绝对失重量与试验时间的变化曲线、24 h试验的磨痕演变规律以及SEM微观形貌,研究Q235、45#和40Cr钢及HT200铸铁4种叶轮常用金属材料的磨蚀特性。结果表明:在冲蚀与空蚀交互磨损下,材料的失重量与磨损时间接近正比;试件的磨痕沿水流方向,在空蚀孔两边呈彗星状分布;沙粒对Q235等塑性材料微切削过程中,动能转化为材料的塑性变形功,使材料产生塑性流动,形成犁沟状磨痕;对于脆性材料HT200,空泡溃灭和沙粒的冲击超过其弹塑性变形极限,使材料产生微裂纹、微体积疲劳剥落,形成蜂窝状蚀坑。相同硬度下,塑性材料耐交互磨蚀性能优于脆性材料。更多还原

【Abstract】 Through simulating turbine working condition on interactive erosion and cavitation wear,the abrasion characteristics of Q235,45 and 40Cr steel,and HT200 cast iron were studied,and the change curves between material’s absolute weight loss with experimental time were obtained.The wear scar evolution of four materials during the 24 h experiment was compared and the specimen microstructure was observed by SEM.The results show that the weight loss of material is about in direct proportion to the abrasion time under interactive wear;the specimen wear scar along the flow direction takes a comet formation distribution on both sides of the cavitation hole;during the process of sand micro-cutting on plastic material such as Q235 steel,the kinetic energy is converted to plastic deformation work,which causes material plastic flow and forms furrow-like wear scar;brittle material like HT200 cast iron,the bubble collapse and sand impact exceeds its elasticplastic deformation limit,as a result,micro-cracks,fatigue spalling and honeycomb pits are generated for material;the wear resistance of plastic material is better than that of brittle material at the same hardness.更多还原