油膜轴承巴氏合金蠕变特性与寿命研究

发布时间：2018-04-19 04:27

  本文选题：油膜轴承 + 巴氏合金　； 参考：《太原科技大学》2014年硕士论文

【摘要】：油膜轴承作为承载部件广泛应用于冶金、航天、矿山等大型设备中，其中衬套巴氏合金是油膜轴承中最易损伤的零件；巴氏合金具有良好的耐磨性能，属于低熔点合金，在工作过程中会发生明显的蠕变现象；蠕变对油膜轴承的使用性能会产生不可忽略的负面作用。本文基于相关金属蠕变理论，明确了研究的方法和具体内容，对油膜轴承巴氏合金SnSb11Cu6的蠕变特性与寿命进行了系统地研究，主要内容简述如下： 首先，对比分析了国内外蠕变试验标准要求，针对巴氏合金SnSb11Cu6设计了满足试验标准要求的蠕变试验设备，提出了SnSb11Cu6蠕变试验的具体操作规程；通过研究蠕变试验方法，证实了通过增加加热时间、保温时间和加载速度，减小初始力，可以缩短合金到达稳态蠕变阶段的时间，使试验周期缩短了73%。同时，通过SnSb11Cu6蠕变试验证实了SnSb11Cu6在实际工作条件下会发生明显的蠕变现象，并获得了SnSb11Cu6的蠕变力学性能；其中，应力对合金的蠕变应变和稳态蠕变速率影响最大，温度对合金减速蠕变阶段的持续时间影响最大。 其次，基于蠕变试验数据，对比分析了四种蠕变模型的准确性，确定了基于McVetty公式和Dorn公式的SnSb11Cu6蠕变模型用于计算SnSb11Cu6蠕变的精度最高，稳态蠕变阶段相对误差仅为1.64%。同时，利用蠕变试验数据分别建立了基于Dom理论和基于恒速理论的两个稳态蠕变本构方程，并通过试验验证了基于Dom理论的稳态蠕变本构方程的计算精度较高，相对误差仅为1.52%。 然后，基于蠕变试验结果，利用拉伸试验、硬度实验和金相实验，分析了合金蠕变、力学性能和显微组织之间关系，得知蠕变降低了SnSb11Cu6的强度、塑性及抗弹性变形能力，并得到了合金蠕变机理，明确了SnSb11Cu6蠕变变形是应变硬化与再结晶回复长时间交替作用的结果。基于硬度实验获得了合金硬度随温度变化的计算公式，确定了SnSb11Cu6的蠕变临界温度为50~60℃。同时，提出了应用ANSYS对巴氏合金进行蠕变分析的方法，并对蠕变试验试件进行了有限元数值模拟，对比分析了三种典型隐式蠕变模型的准确度，确定模型11（时间硬化隐式蠕变模型）描述巴氏合金蠕变特性的精度最高，稳态蠕变阶段相对误差为2.6%；ANSYS数值解与SnSb11Cu6蠕变模型理论计算值相比，本文建立的SnSb11Cu6蠕变模型计算准确度较高。 最后，基于SnSb11Cu6稳态蠕变本构方程，建立了油膜轴承SnSb11Cu6蠕变寿命计算模型；根据合金蠕变后的电阻率和硬度的测量结果，，建立了基于电阻率的SnSb11Cu6蠕变寿命评估模型，提出了一种通过测量合金电阻率评估轴承使用寿命的方法。而且，利用已建立的蠕变寿命计算模型，编写了油膜轴承巴氏合金蠕变寿命预测软件，可以为延长油膜轴承使用寿命提供一定的技术支持。
[Abstract]:Oil film bearing is widely used in metallurgical, spaceflight, mining and other large equipment, among which bushing Babbitt alloy is the most easily damaged part in oil film bearing, and Babbitt alloy has good wear resistance and belongs to low melting point alloy.There is obvious creep phenomenon in the working process, and creep will have a negative effect on the performance of oil film bearing.In this paper, based on the theory of metal creep, the research methods and specific contents are defined, and the creep characteristics and life of SnSb11Cu6 of oil-film bearing are studied systematically. The main contents are summarized as follows:Firstly, the requirements of creep test standards at home and abroad are compared and analyzed. According to the creep test equipment designed by SnSb11Cu6, the specific operation rules of SnSb11Cu6 creep test are put forward, and the creep test methods are studied.It is proved that by increasing the heating time, holding time and loading speed and decreasing the initial force, the time to reach the steady state creep stage of the alloy can be shortened, and the test period can be shortened by 73%.At the same time, through the SnSb11Cu6 creep test, it is proved that SnSb11Cu6 will have obvious creep phenomenon under the actual working conditions, and the creep mechanical properties of SnSb11Cu6 are obtained, among which, the stress has the greatest influence on the creep strain and steady state creep rate of the alloy.The temperature has the greatest influence on the duration of alloy deceleration creep stage.Secondly, based on the creep test data, the accuracy of the four creep models is compared and analyzed. It is determined that the SnSb11Cu6 creep model based on McVetty formula and Dorn formula has the highest accuracy in calculating SnSb11Cu6 creep, and the relative error in steady state creep stage is only 1.64%.At the same time, two steady state creep constitutive equations based on Dom theory and constant velocity theory are established by using creep test data, and the calculation accuracy of steady state creep constitutive equation based on Dom theory is verified by experiments. The relative error is only 1.52%.Then, based on the creep test results, the relationship among creep, mechanical properties and microstructure of the alloy is analyzed by tensile test, hardness test and metallographic test. It is found that creep reduces the strength, plasticity and elastic deformation resistance of SnSb11Cu6.The creep mechanism of the alloy is obtained, and it is clear that the creep deformation of SnSb11Cu6 is the result of long alternating effect of strain hardening and recrystallization recovery.Based on the hardness experiment, the formula of the change of hardness with temperature was obtained, and the critical creep temperature of SnSb11Cu6 was determined to be 50 ~ 60 鈩

本文编号：1771596