Experimental Investigation On Tin Based Babbitt Composite Material
Gawate Atul Vitthal1 , Amol N. Patil2 , Kharad B.N.3
1Sholar,Dept of Mechanical Engg, Vishwabharti Academy’s College of Engineering, Ahmednagar, Maharashtra, India
2Asst. Prof. Dept of Mechanical Engg, Dr. D.Y.Patil School of Engineering, Pune, Maharashtra, India
3Asst. Prof. Dept of Mechanical Engg, Vishwabharti Academy’s College of Engineering, Ahmednagar, Maharashtra, India ***
Abstract - B83BabbitisawidelyusedmaterialinRussian engineering for manufacturing journal bearings through casting,hardfacing,andmetallizationprocesses.Thisalloyis known for its low friction coefficient and desirable properties such as rapid conformability, good thermal conductivity,highimpactviscosity,andcompatibilitywith oil. However, the low fatigue strength under alternating loadsandmoderatewearresistanceofBabbittcanreduce the operational lifespan of the bearing. To address these limitations, ceramic particles are incorporated into the matrixalloytoenhancetheload-bearingcapacityandwear resistanceofcompositematerials.Inthisresearch,thestir casting method is employed to fabricate a Babbitt metal matrix composite by reinforcing it with silicon carbide at varyingconcentrationsof2%,4%,and6%.
1. INTRODUCTION
The B83 Babbit alloy, a popular material in Russian engineering, is commonly used for manufacturing sleeve bearings through casting, hard facing, and metallization processes.Thisalloyoffersseveraladvantageousproperties, including a low friction coefficient, rapid conformability, good thermal conductivity, high impact viscosity, and compatibility with both petroleum and synthetic oils. However, the fatigue strength under alternating loads is relativelylow,andthewearresistanceofBabbitismoderate, resulting in reduced operational lifespan for components madefromthismaterial.Currently,Babbitalloys,specifically Sn-Sb-Cu alloys, are extensively employed in various industries, including the sugar industry, shipbuilding, and automotiveindustry,asthematerialforslidingbearingsthat operateinoil.
1.1. Introduction to Wear
Wearisthegraduallossorremovalofmaterialfromoneor both surfaces in contact due to relative motion between them.Itisasignificantfactorthatsignificantlyreducesthe effectivelifespanofmachinesandtheircomponents.Wear occurs when two surfaces experience relative motion. It involves the progressive removal of material from one surface in relation to the other. The process of wear is complex and involves the gradual deterioration of the
surfaces,resultinginchangesinshape,weightloss,andthe generationofdebris.
2. SUMMARY OF LITERATURE SURVEY
The incorporation of nanoparticles in metal matrix composites can enhance the wear resistance, damping properties,andmechanicalstrengthofthebasematerial.
Babbittbearingsexhibitexcellentconformability,meaning theycanadapttosmallmisalignmentsorshaftdeflections.
The properties of metal matrix composite materials are influenced by various processing parameters in the stir castingprocess,suchasstirringtemperature,stirringspeed, stirring time, preheating time, as well as the selection of matrixandreinforcements.
3. PROBLEM STATEMENT
Thebearingusedinboilerfeedpumpsoperatesunderhighspeedconditions.However,whensubjectedtoexcessively heavyloadsandhigh rotational velocitiesoftheshaft, the bearingispronetodamage,especiallyifanadequateoilfilm thicknessisnotpresentbetweentheshaftandthebearing.
• Excessive wear leading to bearing failure is a significant causeoffailuresinboilerfeedpumps.Inindustrieslikethe sugar industry, pump failure can disrupt subsequent operationsandresultinsubstantialfinanciallosses.
•Thisissue can be addressed by reinforcingmetal matrix compositeswithsiliconcarbideparticles,whichcanenhance thebasematerial'swearresistance,dampingproperties,and mechanicalstrength.
3.1 Objectives
Theprimaryobjectivesofthisprojectareasfollows:
To perform wear tests on B83 Babbit and B83 Babbit-SiC compositematerialswithvaryingcompositions,loads,and slidingspeeds.
ToinvestigatethetribologicalpropertiesofBabbittandits compositematerialswithdifferentcompositions,aimingto identify the most suitable composite material for use in boilerfeedpumpbearingsbasedonwearcharacteristics.
Composition of composite material
TableNo.3.1BabbitCompositeMaterialsComposition
For sample preparation the following chemical compositionistaken.
a) Sample1–Babbitmetal+2%SiCPowder
b) Sample2–Babbitmetal+4%SiCPowder
c) Sample3–Babbitmetal+6%SiCPowder
Metal powder and silicon carbide powder are accurately measuredusinganelectronicweighingmachine.Toserveas a metallic binder, phenolic formaldehyde resin powder is employed.Tin,antimony,copper,andSiCpowderarethen combinedinaplanetaryballmillandmixedforastandard durationof30minutestoachieveuniformblendingofthe powders. The resulting mixture is compacted using a compressionstrengthtestingmachinewithaloadof450KN.
3.2. Wear Test
The fabricated samples were utilized for conducting tribologicalteststomeasurewearandfriction.Thepin-ondisc apparatus was employed to evaluate the tribological propertiesofthecompositematerials.Thisapparatusallows for the determination of important properties such as the frictioncoefficientandwearrate.
3.2.1 Pin on Disc Apparatus (TR20PHM400)
3.2.2 Experimental Procedure
Prior to conducting the wear test using the pin-on-disc apparatus,certaincalculationswereperformed.Thesliding velocity(Vs)wasdeterminedusingtheequationV=π*D*
N/60.Theshaftdiameterandspeedwereobtainedfromthe pump specification data and set as 50 mmand 2900 rpm, respectively.
3.3
Table
4. RESULTS & DISCUSSIONS
4.1 Wear Test Results
4.1.1 Wear vs. Time
Theobtainedweartestdatawasanalyzedbycomparingthe graphs while considering the influencing parameters, includingthenormalload,percentageofsiliconcarbidein babbit,andslidingspeedforallfourmaterialcompositions.
The babbit material exhibited the highest wear under all loadingconditions.Among thedifferent compositions,the addition of 4% silicon carbide (SiC) in babbit showed the leastwearforallloadingconditions,withaminimumwear of 8 micrometers observed at a normal load of 49.05 N. Babbit with 4% SiC had higher wear compared to Babbit with2%SiC,butlowerwearcomparedtoBabbitwith6% SiCandpureBabbitforallnormalloads.Theweargenerally increased linearly with time, except at a load of 88.29 N, wherethewearplotshowedapeakandsubsequentdropin wear.Fromthewearvs.timeplot,itcanbeobservedthatthe material composition of Babbit with 2% SiC exhibited the least wear compared to all other compositions. The wear rateincreasedwithanincreaseinthepercentageofsilicon carbideinthematerialcomposition.
4.1.2
Thetemperatureofthepinwasplottedagainsttimeforall normal load conditions. Figures 4.5 to 46 display these graphsatdifferentloads.Itwasobservedthatasthewear rate increased, the temperature also increased. Babbit exhibitedthehighesttemperatureduetothehighestwear observed in this material. On the other hand, the pin temperaturewasminimuminBabbitwith2%SiCcompared to all other materials. The lowest pin temperature was observedinBabbitwith2%SiCataloadof49.05N.
ThewearversusnormalloadplotispresentedinFigure5.9. Itisevidentthatthewearincreaseswithanincreaseinthe normalload.Babbitmaterialexhibitsthehighestwearatall normalloads.Conversely,theminimumwearisobservedin theBabbit+2%SiCcompositematerial.
The plot depicting the relationship between wear and pin temperatureispresentedinFigure5.10.Itcanbeobserved that as the wear of the material increases, the pin temperature also increases. The lowest temperature recordedis26°C,whilethehighesttemperatureobservedis 33°C.
5. CONCLUSIONS
TheweartestwasconductedonBabbittanditscomposite materialsatvariousnormalloadsandslidingspeeds.Itwas observed that wear increases with an increase in normal loadsandpintemperature.
•Basedontheweartestresults,itcanbeconcludedthatthe Babbitt+2%siliconcarbidecompositematerialexhibitsthe lowestwearcomparedtotheexistingBabbitt,Babbitt+4% SiC,andBabbitt+6%SiCcompositematerials.
• The statistical analysis indicates that the percentage of silicon carbide in the composite material is the most influentialfactoraffectingwear.
• The response optimization for wear revealed that the optimum level for minimum wear is achieved with 2% silicon carbide composites, a normal load of 49.05, and a rotationalspeedof1115RPM.
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