The most common solution of crankshaft bushes is to build up in two layers: Cu-Pb alloy as sliding surface inside, and Low-Carbon alloyed as supporting layer. Using X-ray diffraction machine analyze the elements contented along section, a picture as left should be presented. This happens especially at the point between sliding layer and supporting layer joining.
Sliding: Pb 23 percent 25 percent ; Cu 75 percent 77 percent
Support:C/0.05 percent 0.1 percent ;Mn/0.35 0.45 percent ;Si/0.15 percent 0.20 percent ; S<0.05 percent ; P<0.05 percent .