What is Powder Metallurgy( PM) ?

Powder Metallurgy is one of the continuously and rapidly evolving technology relating with most metallic and alloy material, and a wide range of shape and sizes. Powder Metallurgy is a very developed way of manufacturing reliable ferrous and non-ferrous products. The Europe Market single-handed has an annual turnover of over Six Billion Euro, with annual metal powder production exceeding one million tons.

Created by mixing elemental or alloy powders and compacting the mixture in a die, the resultant shapes are then heated or "sintered" in a controlled atmosphere furnace to bond the particles metallurgical. The high precision forming capability of PM generates components with near net shape, intricate features and good dimensional precision pieces are often finished without the need of machining.

By producing parts with a homogeneous structure the PM process enables manufacturers to make products that are more consistent and predictable in their behavior across a wide range of applications. In addition the PM Process has a high degree of flexibility allowing the tailoring of the physical characteristics of a product to suit your specific property and performance requirements. These include:

§  Structural pieces with complex shapes

§  Controlled Porosity

§  Controlled performance

§  Good performance in stress and absorbing of  vibrations

§  Special properties such as hardness and wear resistance

§  Great precision and good surface finish

§  Large series of pieces with narrow tolerances

The unique flexibility of the PM process enables products to be made from materials that are tailored to your specific needs. By using specially selected materials this capability enables refinements to be engineered into the mechanical properties of the part.

Economical Advantage:

The rise of the P/M industry during the past few decade is highly recognizable to the cost savings related with net shape processing compared to other metal working technique, such as casting or forging. In some case, the conversion of a cast component to powder metal provides a cost savings of 40% or higher.

PM typically uses more than 97% of the starting raw material in the finished part and is especially suited to high volume components production requirements.

There are two principal reasons for using a powder metallurgy product:

1.    cost savings compared with alternative processes, and

2.    unique properties attainable only by the PM route

In the automotive sector, which consumes about 80% of structural PM part production, the reason for choosing PM is, in the majority of cases, an economic one.

PM process enables products to be made that are capable of absorbing up to 35% of selected fluids.

Why then is PM more cost effective?

Better material utilization with close dimensional tolerances. Conventional metal forming or shaping processes, against which PM competes, generally involve significant machining operations from bar stock or from forged or cast blanks.

These machining operations can be costly and are wasteful of material and energy. This is illustrated in the figure below which shows that material utilization in excess of 95% can be achieved with close dimensional tolerances.

Raw material utilization and energy requirements of various manufacturing processes.

This is a comparison between various manufacturing processes (Casting, Cold or Warm Extrusion, Hot Drop Forging, and Machining Processes) and PM -sintering for a production of notch segments for truck transmission.

The PM process has:

§  The highest raw material utilization (over 95%)

§  and the lowest energy requirement per Kg of finished part

§  comparing with the other manufacturing processes

Energy Savings

The energy savings alone contribute significantly to the economic advantage offered by PM..

An example is given below for a notch segment used in a truck transmission, where PM consumes only around 43% of the energy compared with forging and machining and the number of process steps has been greatly reduced. .

Comparison of the PM Process and Forging and Machining (energy requirements and number of process steps)

This is an example for a notch segment used in a truck transmission, where:

§  PM consumes only around 43% of the energy compared with forging and machining, and

§  the number of process steps has been greatly reduced

PM process:

Forging and machining :

Cost Comparison between PM and Forging: