Babbitt Metal

Mahatma Gandhi MissionsCollege of engineering and technologyNoida, U.PBabbitt Metal Presented by: Guided by: Prince Raghu Mr. A.K Sinha

ContentIntroductionHistoryWorking and CompositionTypes of Babbitt Metal Selection of Babbitt metal

ContentModern Babbitt MetalCasting of MetalMechanical properties Microstructure of Babbitt MetalAdvantages and DisadvantagesConclusion and References

IntroductionBabbitt metal ,also called white metal.It is a white non-ferrous alloy which is used provide a bearing surface.

History Babbitt was first created by Issac Babbitt.

In 1839 , he received a patent for a white metal alloy that showed excellent bearing properties. HOW BABBITT WORKS.It provides a bearing surface itself ,which relatively has low coefficient of friction .

This means ,even without lubrication ,Babbitt bearings will have much less friction than if a shaft was turning in other metal.

However ,with the addition of simple lubrication ,Babbitt bearing can have amazingly low coefficient of friction even lower than that of ball bearing .Types of Babbitt MetalBabbitt metal can generally be broken into two major families :Tin based alloy Lead based alloy

Difference b/w Lead and Tin based Alloy Lead TinThe composition range from 15 to 10 % Sn ,10% tin and rest lead.The composition range from 80 to 90% tin ,3.5% Cu,4 to 14% Sn .Lead - based materials are less costly.Tin based material are costlier.They are softer than tin based alloy .On the increment of Cu & Sn increases hardness.It will work fine for most light duty &low speed applications .It is the best choice for high speed applications such as planer and jointers. Selection of Babbitt Metal In selecting the proper type of Babbitt for a particular job , number of factors to take into the consideration ,the most important of which are as follows:Surface speed of the shaft.Load that bearing is required to carry.

Modern Babbitt BearingUntil the mid 1950s poured Babbitt bearing were common in automotive industry.

In more modern practice , Tin based Babbitt bearing were used as they could stand up to impact load found on the connecting rod or crank shaft.

Casting of Babbitt Metal

Babbitt MetalPouring molten MetalTypes of Casting Method Hand Casting :

Centrifugal Casting :

Mechanical properties of Babbitt MetalMelting temperature for common Babbitt varies from 350 F (176.7 C) to 475F (246.1 C) Babbitt has good load carrying capacity between 800 PSI (5.5 MPa) and 1500 PSI (10.3 MPa)The Tensile strength of common Babbitt bearing is about (77 MPa).Although Babbitt bearings can't take extremely high speeds, they can certainly take up to (4000 rpm) if properly lubricated.

Microstructure of Babbitt MetalThrough the microstructural examination we found the following picture of structure:

AdvantagesIt can be easily machined .

It has excellent corrosion resistant properties.

It is cheap and easily available.

It reduces metallic contact and extend the bearing life.DisadvantagesThey are suitable for relatively low temperature.

It has low thermal conductivity.

It has less tendency for welding.

Failure of lubrication will lead to heat build up due to the friction which decreases the bearing life.

Recycling of Babbitt MetalBefore re-melting and re-machining on Babbitt scrap various methods are followed by the industry to remove impurities with Babbitt scrap are as : Magnetic separatorRotary dryerCrucible furnace

Real World ApplicationIn automobile industry : As a crankshaft and connecting rod .

In rolling - element bearings :As a ball and ball bearings.

It is used as a cast iron pillow block which is assembled as a loose fit around the shaft . ConclusionThe coating and repairing of boiler feed pump bearing and CWP pump has been investigated. Wire flame thermally spraying process, melting process and metallurgical analyses are employed for this purpose. A summery of conclusions is as follow: The bonding strength of thermally sprayed Babbitt layer is higher than melting processes. The hot spots which are the result of thermal barrier oil film in the Babbitt -substrate interface eliminated completely in thermally sprayed coatings.

Referenceshttp://www.alchemycastings.com/lead-products/Babbitt.http://www.frymetals.com/products/babbitt.html?product=babbitt|Fry Metals Babbitt

Kapp Alloy & Wire, Inc."Kapp Eco-Babbitt". Kapp Alloy & Wire, Inc. Retrieved 10 April 2013.

Hellemans, Alexander; Bunch, Bryan (1988).The Timetables of Science.Simon & Schuster. p.305.ISBN0671621300.Thank you