. Transactions. , in. Brinell 8,.500 10,000 11,000 12,000 13,000 JESSE L. JONES 463 The lead-base babbitt withstood compression better than the tin-basebabbitt. When the load was increased to 30,000 lb. per square inch,however, the latter presented the better appearance, as the babbitt hadflowed uniformly in all directions over the edge of the bronze square,while the lead-base babbitt compressed more on one side than on theother, and the sample tilted in spite of the rocker
. Transactions. , in. Brinell 8,.500 10,000 11,000 12,000 13,000 JESSE L. JONES 463 The lead-base babbitt withstood compression better than the tin-basebabbitt. When the load was increased to 30,000 lb. per square inch,however, the latter presented the better appearance, as the babbitt hadflowed uniformly in all directions over the edge of the bronze square,while the lead-base babbitt compressed more on one side than on theother, and the sample tilted in spite of the rocker device. At a load of30,000 lb. per square inch, the bronze also flowed appreciably. These tests show that broaching, peening, etc., do not appreciablyincrease the hardness of babbitt, and that hardness must be obtained byquick cooling of the lining by water-cooled mandrels, etc. ^Microscopic examination of a lead-base babbitt discloses a matrix orgroundmass of several eutectics in which are embedded hard cubical. Fig. 5.—Mills micrometer roller. crj^stals of tin antimonide. These crystals, being relatively low in specificgravity, tend to be more numerous in the upper portion of a babbittlining. This lack of uniformity is guarded against by pouring a thinlining and chilling quickly. The secret of obtaining good bearingsconsists in keeping this matrix tough and hard. The same remarkapplies to the tin-base babbitts, although in these there is less tendencyfor the tin antimonide crjstals to rise to the surface, owing to the lowerspecific gravity of these babbitts. Rolling of Babbitted Linings by the Mills AIickometer Roller As the above test of Brinell hardness of babbitt after compressionshowed practically no change in hardness, it was concluded that thevarious methods of finishing babbitted bearings, such as peening, broach-ing, and reaming, did not improve the hardness of the babbitt. As, 464 BABBITT AND BABBITTED BEARINGS after these operations and the final scraping, it is s
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Keywords: ., bo, bookcentury1800, bookdecade1870, booksubjectmineralindustries
