Comparative Study on the Machinability and Manufacturing Cost in Low-Lead Brass

Today, commercially used brasses commonly contain 2 to 4 wt.% lead. As the availability of low-lead and lead-freebrass increase, there are environmental incentives for investigating the consequences of replacing thelead-containing brasses with lead-free equivalents. Generally, lead-free brass is expected to have a lowermachinability than its lead-alloyed counterpart, implying a higher manufacturing cost. Thus, the aim of this studyhas been to quantify the added manufacturing cost by replacing a standard brass alloy with a low-lead alternative.This was done through a case study performed at a Swedish SME which replaced CuZn39Pb3 (3.3 wt.% Pb) withlow-lead CuZn21Si3P (<0.09 wt.% lead) for a select part. Since CuZn21Si3P is almost twice as expensive asCuZn39Pb3, the material cost was found to have a substantial influence on the manufacturing cost. Additionally,the lower machinability implied a longer cycle time and higher losses while machining CuZn21Si3P, resulting in a77% overall increase in manufacturing cost when using the low-lead material. Arguably, the difference in materialcost, and thus manufacturing cost, may decrease over time making production of low-lead and lead-free brassproducts a viable option, especially when considering the environmental incentive for decreasing the amount oflead in circulation.