Mahatma Gandhi Mission’sCollege of engineering and technology Noida, U.P “Babbitt Metal” Presented by: Guided by: Prince Raghav Mr. A.K Sinha INTRODUCTION •Babbitt 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 BABBIT 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 Metal • Babbitt metal can generally be broken into two major families : • Tin based alloy • Lead based alloy Difference b/w Lead and Tin based Alloy Lead Tin • The composition range from 15 to 10 % Sn ,10% tin and rest lead. • The composition range from 80 to 90% tin ,3to 8% Cu,4to 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. Eco – Babbitt… • Generally , composition Babbitt alloy has found about 90%Sn 7%Zn 3%Cu that is not technically a Babbitt metal. Selection of Babbitt Metal • In selecting the proper type of Babbitt for a particular job , number of factor 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. Recycling of Babbitt Metal • Before re-melting and re-machining on Babbitt scrap following methods are followed by the industry to remove impurities with Babbitt scrap are as : Magnetic separator Rotary dryer Crucible furnace Modern Babbitt Bearing • Until 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. Babbiting • The inner surface of the steel shell is plated with the coating of bronze which is in turn coated with thin layer of Babbitt metal as bearing surface . • The process of laying down this layer of white metal is known as “babbitting” .