Powder metallurgy (PM) is a net shape process used to provide a wide variety of structural
components to automotive and non-automotive industries
PM has a higher material utilization (95%) compared to other competing technologies due to the ability to manufacture net shape components. While the material utilization is quite high, the majority of PM components undergo some type of machining operation.
Machining is complex process with many factor affecting the overall machinability of the component
hining is complex process with many factor affecting the overall machinability of the component. Numerous options exist to improve the machinability through tooling and machining parameters.
Another popular route is to improve the machinability of the material through the addition of a machinability enhancing additive. The most common additive used in the industry today is manganese sulphide (MnS). Borrowing from the wrought free machining steels, MnS has been a dependable additive to provide improved turning and drilling performance. If added below 0.5%, there is no degradation of mechanical performance. However, due to the hygroscopic nature of MnS, it has a
propensity to gather moisture from the surrounding environment. The end result of this process is a degradation of the corrosion resistance which can cause issues during storage and service of components containing MnS.
SM4, which provides improvement in turning and drilling operations. The new additive provides this improvement with little effect on mechanical performance and no effect on corrosion resistance