This part is the conclusion of previous 12 parts, especially describing the effects of the Pb % on the machinability and the wear resistivity are fully discussed. There are two sides of the effects of Pb on the properties of brass ; one is the static effect and the other is dynamic one. The static one is not so large, but the dynamic one is very severe. So the shock value of the brass containing nearly 2% of Pb is about half of that of ordinary brass without Pb.
The cutting phenomenon is entirely affected by the dynamic property of the brass to be cut, so the cutting force is rapidly decreased by adding Pb. The wear phenomenon, however, is affected by the dynamic property as well as the static one. Both effects on wear are not so large, that, for example, the brass with more than 2% Pb shows the low resistivity against wear at the annealed state, but if we strengthen its static property by cold working, we have the Pb-brass with nearly as high wear-resistivity as the ordinary brass.
