High Current Resistance Sintering For Producing Brass Powder Components

Heat-treatment (sintering) is essential for manufacturing metal components through powder metallurgy (P/M) route. A typical heating eliminates the inter-particle surfaces of metal powder. Thus a metal powder component gets consolidated into one mass. Conventional muffle furnace heating (MFH) is common means to heat-treat a powder component. However, apart from dezincification (escaping of volatile zinc) of brass components, the method is time consuming, costlier and occupies more space. In this work, an alternative method is proposed. Direct resistance heating method is employed for this purpose. A high current (5.8 kA) ac-to-dc converter and a time delay circuit are used. Only the magnitude and the duration of the current through the component are controlled. A high current of the order of kA shows better results and it avoids dezincification too. Microstructures of components are also analyzed which give satisfactory results.