如何进行轴承故障分析

什么是轴承故障分析？

What is a Bearing Failure Analysis?

轴承故障分析是收集和分析轴承数据以确定轴承故障原因的过程。

Bearing Failure Analysis is the process of collecting and analyzing bearing data to determine the cause of a bearing failure.   

需要轴承故障分析时

When a Bearing Failure Analysis is needed

轴承故障分析是客户要求对报告的轴承故障进行轴承分析时使用的重要工具。在开发新的或改进的轴承产品和应用中，这也是必不可少的。

Bearing Failure Analysis is a vital tool used when bearing(s) are submitted by a customer who requests a bearing analysis of a reported bearing failure.   It is also essential in the development of new or improved bearing products and applications.

执行轴承故障分析

Performing the Bearing Failure Analysis  

收集故障数据：

Collecting failure data:

- 获取与轴承故障相关的所有故障组件，如：轴承，轴承座，配合表面和其他相关材料（例如润滑剂或流体，磨损碎屑，密封件和应用组件）。

- 确认实际操作条件数据，例如负载，速度，温度，扭矩，润滑剂，流量；在材料应用数据表中找到的参数。

- 获取测试/故障数据，例如测量尺寸和性能参数的输出，测试或服务时间，客户报告故障的原因。

- 获得应用中使用材料的规格（轴和外壳的材料规格，润滑剂和流体的规格），甚至是客户的设计FEMA。

- Obtain all the failed components related to the bearing failure (bearing, housing, mating surface) and other related materials such as lubricants or fluids, wear debris, seals and application components.   

- Confirm actual operating conditions data such as load, speed, temperature, torque, lubricant, flow rate; parameters that are found on a Materials Application Data Sheet.

- Obtain test/failure data such as printouts of measured dimensional and performance parameters, time of test or service, customer’s reason(s) for reporting a failure.

- Obtain specifications for materials used in the application (shaft and housing material specifications, lubricant and fluid specifications) and even the customer’s design FEMA.  

分析数据：  

Analyzing the data:  

• 使用和/或不使用显微镜目测检查失效的组件。照片应根据需要拍摄。重点应放在但不限于以下故障问题：严重磨损；异常磨损情况；变色；碎片；变形；分层；预期的滑动表面以外的轴承损坏。

• 对运行数据进行技术审查，以确认轴承材料和总体设计是否适合实际运行条件。 该步骤将包括但不限于将实际工作参数（单位载荷（p），速度（U），pU，温度）与轴承材料性能进行比较； 确定轴承材料对可能存在的流体或气体的化学耐受性； 使用实际运行参数估算干摩擦轴承寿命； 或者，如果是润滑应用，则估计润滑方式（边界，混合膜，全流体动力膜）。

该技术审查应确认轴承应符合轴承性能的操作要求。 否则，则可能意味着轴承材料的选择是导致故障的原因，有待进一步检查失效的轴承和组件。

仅这两个基本步骤可能会得到对轴承故障的满意反馈，或者可能表明需要进一步战略 - 使用多种无损和破坏性方法来进行尺寸测量和/或材料分析，例如：

- 使用坐标测量机（CMM）

- 测量表面纹理

- 音蚀测试

- 差示扫描量热法（DSC）观察熔融和结晶以及玻璃化转变温度 Tg

- 热重分析（TGA）以评估材料的热稳定性

- 能量色散X射线光谱法（EDS，EDX或XEDS），以确定样品中存在哪些化学元素并估算其相对丰度

- 材料硬度测试

- 拉伸/压缩测试

- 三瓦磨损测试

- 耐腐蚀性测试

• Visual examination of the failed components with and/or without a microscope.  Photographs should be taken as needed.  Focus should be on, but not limited to, the following failure issues: severe wear; abnormal wear pattern; discoloration; debris; deformation; delamination; damage to bearing other than the intended sliding surface.

• Technical review of operational data to confirm suitability of the bearing material and overall design to the actual operating conditions.  This step will include, but not limited to, comparing of actual operating parameters (specific load (p), speed (U), pU, temperature) with bearing material properties capabilities; determination of bearing material’s chemical resistance to fluids or gases that may be present; estimate dry bearing life using actual operating parameters; or, if the application was lubricated, estimate lubrication regime (boundary, mixed-film, full hydrodynamic film).   

This technical review should confirm that the bearing should have met the operational requirements for bearing performance.  If not, this may mean the bearing material selection was the reason for failure pending further examination of the failed bearing and components.

These two basic steps alone may lead to a satisfactory response to the bearing failure or may indicate a need to develop a strategy for advanced steps of dimensional measurements and/or material analysis using a wide array of non-destructive and destructive methods like:

- Using a coordinate-measuring-machine (CMM);

- Measuring surface texture

- Sonic erosion tests

- Differential Scanning Calorimetry (DSC)  to observe fusion and crystallization events as well as glass transition temperatures Tg

- ThermoGravimetric Analysis (TGA) to evaluate the thermal stability of a material

- Energy-Dispersive X-ray Spectroscopy (EDS, EDX, or XEDS) to determine which chemical elements are present in a sample and to estimate their relative abundance

- Material hardness tests

- Tensile/compressive tests

- Three-shoe wear tests

- Corrosion resistance tests

出具报告：

Issuing the report:

无论是仅使用基本分析，还是使用高级分析补充基本分析，故障分析的最后一步就是出具报告。 根据分析的范围，报告可能非常简单或广泛。

基本故障分析报告包含背景信息（包括技术评审），外观检查（可能包括基本尺寸测量）和结论（可能包括建议）就足够了，尤其是如果这是针对给定客户应用程序的例行故障分析。 如果需要更多细节来满足客户，可以添加技术分析。

如果基本分析不足以满足故障分析的需求，那么将需要准备一个策略，该策略首先将使用非破坏性测试/测量技术，并在必要时使用破坏性测试来完成故障分析。 根据对进阶分析的需要，该报告可能包括那些其他分析的报告，以进一步支持该报告的结论和建议。

Whether we use only basic analysis or supplement basic analysis with advanced analysis, the final step in the failure analysis is issuing a report.  Depending upon the scope of the analysis, the report may be very simple or extensive.

A basic failure analysis report may be sufficient with only the Background Information (which includes the technical review), Visual Examination (which may include basic dimensional measurements) and Conclusions (which may include recommendations).  This is may be all that is required, particularly if this was a routine failure analysis for a given customer’s application. Technical analysis can be added if more detail is needed to satisfy the customer.

If the basic analysis is not sufficient to satisfy the needs for failure analysis, then you will need to prepare a strategy that first will use non-destructive test/measurement techniques and, if needed, destructive testing to complete the failure analysis.  Depending upon the need for advanced analysis the report may include the reports of those additional analyses to further support the report’s conclusions and recommendations.