CoreBearing Damage AnalysisTimkenTechnical & Commercial Training11/20/2009CT030004 RevD Brg Damage Analysis1Product/Application/ServiceBearing Damage AnalysisHelp you to analyze, diagnose and correct bearing damageb i dProduct/Application/ServiceBearing DamagePremature bearing damage can be caused by:C t i ti–Faulty mounting–ContaminationProduct/Application/ServiceBearing LifeDepending on application requirements service life can vary greatlylif tlProduct/Application/Service Types of DamageWear from foreign material –Pitting / Bruising / Grooving High spots and fitting practices Improper fit in housings / shaftsEtching / Corrosionp p g False brinellingProduct/Application/ServiceWear From Foreign MaterialOne of the most common sources of damage Foreign material incl desForeign material includesProduct/Application/ServiceWear From Foreign MaterialTypes of wear–Abrasive wearProduct/Application/ServiceWear From Foreign MaterialAbrasive wear–From fine foreign material in the bearing: Sand, fineProduct/Application/ServiceWear From Foreign MaterialAbrasive wearClick icon for a close-up viewSpherical roller bearing fine particleProduct/Application/ServiceWear From Foreign MaterialBruising–Typically caused by large particles, metal chips,Product/Application/ServiceWear From Foreign MaterialBruisingCylindrical roller bearingContamination bruising from hardparticles in spherical roller bearingProduct/Application/ServiceWear From Foreign MaterialBruisingDebris from other fatigued parts,Product/Application/ServiceWear From Foreign MaterialCircumferential lining (grooving)–Caused by extremely heavy wear from chips orTCK2Product/Application/ServiceWear From Foreign MaterialCircumferential lining (grooving)Large particle contamination embedded inSlide 14TCK2 Jim can provide a better image. Look in "How to recognize and prevent ... "Tim Kraft, 1/6/2006Product/Application/ServiceWear From Foreign MaterialPrevention–Regular inspection of sealsProduct/Application/ServiceEtching / CorrosionOne of the most serious problems–High degree of finish on races and rolling elementsProduct/Application/Service Water / Etch Damage Staining 11/20/2009CT030004 RevD Brg Damage Analysis 17Product/Application/Service Etching / Corrosion 11/20/2009CT030004 RevD Brg Damage Analysis 18Etching and corrosion on cylindrical roller bearing inner ring Advanced corrosion and pitting on the cone race and rollersProduct/Application/ServiceEtching / CorrosionHeavy water damage on a ball A tapered roller bearing cup withcorrosion on the raceCT030004 RevD Brg Damage Analysis19Product/Application/ServiceWater / Etch DamageEtching →Roller-spaced Spalling11/20/2009CT030004 RevD Brg Damage Analysis20Product/Application/ServiceEtching / CorrosionPrevention–Inspect and replace worn seals to avoid etchingProduct/Application/ServiceInadequate LubricationAny condition that allows metal-to-metal contact in ag g qbearing can be regarded as “inadequate lubrication”Product/Application/Service Inadequate Lubrication Heat damage on tapered rollers Microspalling (peeling) due to thin Product/Application/Service Inadequate Lubrication 11/20/2009CT030004 RevD Brg Damage Analysis 24Metal flow from excessive heat Scoring of tapered roller ends and rib faceProduct/Application/ServiceLubrication ProblemsHeat discoloration11/20/2009CT030004 RevD Brg Damage Analysis25Product/Application/ServiceInadequate LubricationPrevention–Ensure that an appropriate amount of the correctProduct/Application/Service Fatigue Spalling Pitting or flaking away of bearing material Cyclic fatigue on the rolling contact surfaces caused by repeated stress of the steel –Each time a roller contacts a race, the metal is elastically deformed and stressed, causing the 11/20/2009CT030004 RevD Brg Damage Analysis 27,g spall to grow Product/Application/Service Fatigue Spalling There are many types of “primary” bearing d (b i i itti t hi t )th t damage (e.g. bruising, pitting, etching, etc.) thatProduct/Application/Service Fatigue Spalling: GSC The result of misalignment or edge loading that i iti t hi h t t l li d i f th initiates high stress at localized regions of the Product/Application/Service Fatigue Spalling: GSC 11/20/2009CT030004 RevD Brg Damage Analysis 30GSC spalling from misalignment, deflections or heavy loading on a tapered roller bearingProduct/Application/ServiceFatigue Spalling: PSOMost common spalling damage–Result of very high and localized stress causing theProduct/Application/ServiceFatigue Spalling: PSOSpalling from debris or raised metal exceedinglubricant film thickness on a tapered roller bearing11/20/2009Product/Application/ServiceFatigue Spalling: Inclusion OriginThe result of the bearing material wearing out after millions of loading cycles, at localizedft illi f l di l t l li dProduct/Application/ServiceFatigue Spalling: Inclusion OriginFirst identified11/20/2009CT030004 RevD Brg Damage Analysis34Product/Application/ServiceFatigue Spalling: Inclusion OriginPropagation begins11/20/2009CT030004 RevD Brg Damage Analysis35Product/Application/ServiceFatigue Spalling: Inclusion Origin6 million revolutions: Chevron or “beach marks”11/20/2009CT030004 RevD Brg Damage Analysis36Product/Application/ServiceFatigue Spalling: Inclusion Origin6.9 million revolutions: Spall growth11/20/2009CT030004 RevD Brg Damage Analysis37Product/Application/ServiceFatigue Spalling: Inclusion Origin7.8 million revolutions11/20/2009CT030004 RevD Brg Damage Analysis38Product/Application/Service Excessive Preload or Overload Causes damage similar to inadequate l b i ti d lubrication damage Product/Application/Service Excessive Preload or Overload 11/20/2009CT030004 RevD Brg Damage Analysis 40Overloading on a cylindrical roller bearing caused roller surfaces to fracture Overloading resulted in severe fatigue spalling on the tapered rollersProduct/Application/Service Excessive Preload or Overload 11/20/2009CT030004 RevD Brg Damage Analysis 41High load / low speed caused insufficient lubricant film Severe peeling and wear from high load / low speed on a needle thrust race Product/Application/Service Excessive endplay Components are not seated tightly against th one anotherProduct/Application/ServiceExcessive Endplay11/20/2009CT030004 RevD Brg Damage Analysis43Product/Application/ServiceExcessive Endplay11/20/2009CT030004 RevD Brg Damage Analysis44Product/Application/ServiceExcessive EndplayScalloping11/20/2009CT030004 RevD Brg Damage Analysis45Product/Application/ServiceMisalignmentWhen seats and shoulders supporting bearings aren’t within specified alignment limits, bearing ’t ithi ifi d li t li it b i loads become concentrated–In extreme misalignment, loads are carried only atextreme ends of rolling elements and races11/20/2009CT030004 RevD Brg Damage Analysis46Product/Application/ServiceMisalignmentSources:–Inaccurate seats andshoulders–Deflection from highloads–Out-of-square backingshoulders on shafts orhousings11/20/2009CT030004 RevD Brg Damage Analysis47Product/Application/ServiceMisalignmentShaft HousingProduct/Application/ServiceMisalignmentHOUSINGBORESHAFT11/20/2009CT030004 RevD Brg Damage Analysis49Product/Application/ServiceMisalignmentProduct/Application/ServiceMisalignmentCylindrical roller bearing housing bore wasProduct/Application/ServiceMisalignmentSplit housings11/20/2009CT030004 RevD Brg Damage Analysis52Product/Application/Service Misalignment Pinch point where misaligned housing sections joined 11/20/2009CT030004 RevD Brg Damage Analysis 53sections joined Product/Application/Service Misalignment 11/20/2009CT030004 RevD Brg Damage Analysis 54ID of outer ring showing GSC spall opposite pinch pointProduct/Application/Service Handling & Installation Damage Rolling elements and race surfaces can be d d b h h dli damaged by rough handling Product/Application/Service Handling Damage 11/20/2009CT030004 RevD Brg Damage Analysis 56A hardened driver caused cup face denting on this tapered roller bearingProduct/Application/ServiceHandling DamageSpherical roller bearing inner race with fracturedtoe flange from improper installation11/20/2009CT030004 RevD Brg Damage Analysis57Product/Application/ServiceHandling DamageA hardened driver caused a broken rib onProduct/Application/ServiceHandling DamageProduct/Application/ServiceInstallation DamageRoller-spaced nicking caused by raised metalon races coming in contact with roller edges11/20/2009CT030004 RevD Brg Damage Analysis60Product/Application/ServiceHandling & Installation Damage: Cages / RetainersCages / retainers usually made of mild steel, bronze, or brassb bProduct/Application/ServiceHandling & Installation Damage: Cages / RetainersProduct/Application/ServiceHandling & Installation Damage: Cages / RetainersRoller skewing due to compression ofProduct/Application/ServiceHandling & Installation Damage: Cages / RetainersRough handling caused a deep dent onthis cylindrical roller bearing cage bridge11/20/2009CT030004 RevD Brg Damage Analysis64Product/Application/ServiceImproper Fitting PracticesIn general, the bearing race on or in the rotating element should be applied with a press or tight l t h ld b li d ith ti htProduct/Application/ServiceImproper Fitting PracticesBearing damage from a looseProduct/Application/Service Improper Fitting Practices 11/20/2009CT030004 RevD Brg Damage Analysis 67A fractured cone due to an out-of-round or oversized shaft Product/Application/Service False Brinnelling (Fretting) Grooves in the race caused by rolling elements lidi i ll b k d f th hil sliding axially back and forth on race while raceProduct/Application/ServiceTrue BrinnellingRoller-spaced indents in the raceProduct/Application/ServiceFalse Vs True BrinnellingFalse brinelling wears away the surface texture, while the original surface texture remains in the hil th i i l f t t i i th depression of a true brinellTrue Brinnelling False Brinnelling11/20/2009CT030004 RevD Brg Damage Analysis70Product/Application/ServiceTrue Brinnelling Spherical roller bearing inner ring showingProduct/Application/Service BrinnellingBall bearing inner ring showingProduct/Application/Service Burns from Electric Current When an electric current passes through a bearing, it creates an arc between the races and rolling elements creates an arc between the races and rolling elements Product/Application/Service Burns from Electric Current 11/20/2009CT030004 RevD Brg Damage Analysis 74Pitting / small burns created by arcs from improper electric grounding in stationary bearingProduct/Application/ServiceBurns from Electric CurrentFluting (small axial burns) caused by electriccurrent passing through rotating bearing11/20/2009CT030004 RevD Brg Damage Analysis75Product/Application/ServiceBurns from Electric CurrentRoller with fluting caused by welding performedProduct/Application/Service Cam Failure: Wide Inner Ring Ball Bearings An undersized shaft or an outer ring that cannot b li d d t th h i be aligned due to the housing may cause a Product/Application/Service Cam Failure: Wide Inner Ring Ball Bearings 11/20/2009CT030004 RevD Brg Damage Analysis 78Shaft below suggested tolerance levels Misaligned outer ringProduct/Application/ServiceThe Keys To Long, Trouble-Free Bearing PerformancepProper:Product/Application/ServiceDamage AnalysisYou are the initial point of contactProduct/Application/ServiceDamage AnalysisThoroughly documentyour investigationyour investigationIn Learner Workbook11/20/2009CT030004 RevD Brg Damage Analysis81Product/Application/ServiceBearing Damage AnalysisIt is usually easy to see the damage, but often difficult to determine the causediffi lt t d t i thCoreBearing Damage AnalysisTimkenTechnical & Commercial Training11/20/2009CT030004 RevD Brg Damage Analysis83 CoreCloseup Damage ViewsProduct/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis85 Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis86Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis87 Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis88Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis89 Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis90Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis91 Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis92Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis93 Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis94Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis95 Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis96Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis97Product/Application/ServiceReturn toprevious screen11/20/2009CT030004 RevD Brg Damage Analysis98。
