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An Experimental Investigation of Babbitt Metal Bonding

The Navy's extensive use of babbitt bearings in surface ship 
machinery requires that Navy tenders and repair ships have the 
capability cf repairing babbitt metal bearing.g on board. The 
practice of casting babbitt within the limited facilities Of a 
tender's foundry has evolved over years to a "traditional" pro— 
This m#hod is simpler than 
cedure passed on by crew chiefs . 
the bearing manufacture's methods' , 2 which are designed to optimize 
bearing strength, and require a Large. well—equ ipped facility. In 
present tender practice, the babbitt lining of a bear ing is bonded 
to the steel or bronze bearing shell by means of a tin interface 
Normally. the tin is applied to the hot bearing shell. 
layer . 
after which the shell is set up in a mold and molten babbitt 
poured in. 
The primary difference in the methods is the way in which the 
tin interface layer is applied. Manufacturers are able to use a 
bath of molten tin in which the hot bearing shell is inunersed; 
however, aboard ship the shell is heated by a flame torch, and 
a stick of tin is melted on the shell, much as solder is applied 
to connections. The hot tin layer oxidizes rapidly, while 
cooling, and the subsequent bond is often weak and brittle. 
Many turbine gear, and lineshaft bearings are renewed annual Iy 
because of poor bonding. Furthermore, rebabbitting bearings 
frequently requires excessive man—hours of work because ot the 
unsat isfactory bonding and consequent rework. 
The traditional method, as well as modifications, and 
alternat Ives to this method were investigated to develop and 
recorrunend a simple, improved method of bonding babbitt bearing 
linings to metal Lic bearing shells. The investigation intended 
to characterize the important features of a simple babbitt— 
bonding procedure for possible use in a tender' s foundry. 
Var ious babbitt—bonding procedures were used to make tensile 
specimens of steel bonded to babbitt The breaking strength 
of these specimens vas used to evaluate the relative efficiency 
af several bonding methods, as compared to the standard method 
us ing a tin bath for applying the tin interface layer.