Powder metallurgy consists of compacting a mixture of metal powders in a tool that has the negative shape of the part, and sintering the compacted preform in an oven at a temperature lower than the melting point of the base metal.

The feedstock for a sintered structural steel component is a powder of pure iron or steel. The base powder is often mixed with other alloying elements or additives such as graphite, nickel, copper or others, suitably dosed to achieve the chemical composition of the final material.

The resulting powder mixture is compacted within a tool that has the negative shape of the final part, and pressure is applied according to the final density to be reached.

The compacts are sintered in a furnace. This operation consists in heating the compacted part to a temperature between 1,100 and 1,300 °C under conditions of controlled atmosphere and time. The high temperature causes the powder particles to weld together and the alloying elements to diffuse.

The result of this process is a structurally functional metal part of high dimensional accuracy and a controlled level of microporosity.

Powder metal steel components sometimes require complementary manufacturing operations. The aim is to modify one or more characteristics to make the component functional in the unit in which it is mounted.

• Porosity sealing. This consists of filling the pores with a chemical product. Resin tightens it and copper increases its mechanical strength.
• Oil impregnation. Oil contained in the pores can act as a lubricant of a bearing-shaft interface, hence self-lubrication is provided.
• Sizing. This consists of re-pressing the sintered part in a rigid tool to increase its density, improve its dimensional accuracy and roughness, and/or create relief details.
• Machining. Turning, grinding, milling, drilling, threading, honing, polishing, etc. are used to obtain shapes or tolerances that cannot be achieved directly by compacting.
• Deburring and cleaning. Tumbling, shot blasting, brushing, polishing, ultrasonic cleaning, etc.
• Heat treatments. Quenching and tempering, case hardening, carbonitriding, plasma nitriding, annealing, steam treatment, etc.
• Coatings. Zinc, chrome and nickel plating, phosphating, metallizing, polytetrafluoroethylene coating, etc.
• Joining to other components. Welding, brazing, sinter-bonding, fitting, glueing, riveting, overmolding, etc.