Powder Metallurgy in Mechanical Parts

Powder metallurgy is a manufacturing processing of metal parts that the feedstock consists of metal powders and non-metal powders, is subjected to shaping, sintering, and other procedures, then become finished parts, that is a near net-shaping processing, which is available for unusual material that is difficult for other conventional processings, and is very suited for high precision mechanical parts with complex geometries and special mechanical properties by less worktime and workforce. However the toolings and metal powders cost much, therefore it can achieve the best benefits only when it’s used to mass production.

Nowadays, powder metallurgy technology is developed in two directions.

1, the parts with high load

2, the parts with complex geometry, high accuracy, less machining.

The processings these are applied to making metal parts with complex shapes and tight accuracy, mainly includes combined processings of powder metallurgy with powder forging, injection molding and hot isostatic pressing.

Metal injection molding can achieve around 96% of theoretical density. For example, the nickel rings in transmission system in aircraft wings of Boeing 707 and Boeing 727, are very complex with internal threads. In the past, they were made by forging, and required more than 14 machining procedures. Metal injection molding can manufacture metal parts with little allowance, and require few machining and correcting, besides, with perfect corrosion resistance and mechanical properties.

The combined processings combined with powder metallurgy are available for metal parts with complex geometries, special material, special properties, which normal manufacturing processings can’t make.