Low Pb brass rod and manufacturing method thereof

摘要

PROBLEM TO BE SOLVED: To improve the machinability of a brass bar material with a reduced Pb content without deteriorating its recyclability.SOLUTION: There is provided a low Pb brass bar material, being the bar material of a copper alloy having a chemical composition comprising, by mass, 54.0 to 66.0% Cu and 0.05 to 0.50% Pb, containing one or more kinds selected from Sn of 0.40% or lower, Fe of 0.60% or lower and P of 0.15% or lower in such a manner that the total content of the Sn, Fe and P reaches 0.02% or higher, and the balance Zn with inevitable impurities, and having a metallic structure where Pb-concentrated particles are dispersed into a matrix made of an α phase and a β phase, and in the structural observation of the cross-section vertical to the longitudinal direction, the number density of the Pb-concentrated particles present at the inside of the α phase is 150 pieces/mmor higher to the area of the α phase.SELECTED DRAWING: Figure 1