碱性腐蚀环境下接触载荷对钢丝微动疲劳行为的影响

以矿用钢丝为研究对象,在自制的钢丝微动疲劳试验机上开展钢丝在碱性腐蚀环境下的微动疲劳试验,考察钢丝在应变比为0.8时不同接触载荷下钢丝的微动运行特性,并用光学显微镜和扫描电子显微镜观察钢丝的磨痕和断口形貌,分析其微动磨损和疲劳断裂机理.结果表明:不同接触载荷下钢丝的摩擦系数具有相同的变化趋势,均可以分为4个阶段:跑合期、上升期、下降期和稳定期;4种不同接触载荷下钢丝摩擦副均运行于滑移状态,磨损机制以腐蚀磨损、磨粒磨损、疲劳磨损和塑性变形为主;钢丝疲劳寿命与磨损量成反比,疲劳断口可分为3个区:疲劳源区、扩展区和瞬断区.

Effect of Contact Load on the Fretting Fatigue of Steel Wire under Alkaline Corrosive Environment

The fretting fatigue tests of the mine steel wires under alkaline corrosive environment are performded on a self-made fretting fatigue test machine. The fretting fatigue behaviors of steel wires with a strain ration of 0.8 are studied under different contact loads. The damage mechanisms of steel wires are analyzed by the optical microscopy and scanning electron microscopy. The results indicate that the evolution of friction coefficients of steel wires can be divided into four stages, i.e., running-in period, ascending period, declining period and stable period. The fretting regime of steel wires is gross slip regime under the four different contact loads. Corrosive wear, abrasive wear, fatigue wear and plastic deformation are the main wear mechanisms. The fatigue lifetime of the fretted steel wires is inversely proportional to the wear depth. Fatigue fracture surface can be divided into three regions, i.e.,fatigue source region, crack propagation region and transient break regions.