Bearing whitemetal

Bearing whitemetal is a soft tin-based or lead-based babbitt alloy cast or bonded as a thin lining onto the steel or bronze shell of a marine journal or thrust bearing. Tin babbitts run about 88 to 90 percent tin with antimony and copper, giving hard intermetallic crystals carried in a soft matrix. The soft matrix conforms to the journal and embeds dirt; the hard crystals carry load. Whitemetal has low melting point, near 240 degrees C for tin babbitt, so a lubrication failure wipes the lining before it scores the costly journal, making it sacrificial by design. Used on main bearings, crankpin bearings, and stern-tube bearings.