Iron Powders for Sintered Components
Metal powders open up new possibilities for creative and cost-effective design solutions.
Almost 80% of global iron and steel powder production is converted into sintered components. The manufacturing process involves the shaping of a tailor-made powder formulation by pressure and heat (sintering). Sintered components offer design freedom, almost 100% material utilization and many other benefits. Over 40 million sintered components are produced every day for use in numerous applications including vehicles, power tools and white goods.
Our wide selection of iron-based powders, ranging from pure iron to tool steels, ensures the right solution for each part and process.
The automotive industry is the main user of sintered components, which are common in transmission and engine applications. It is in the automotive area that sintered components have made the most spectacular advances. Many of the early parts for vehicles, such as the bushings and bearings introduced in the 1960s were simple shapes. Components of today can be made in highly complex designs and meet the industry’s demands for strength and tolerances.
A modern automobile contains on average 10 kg of sintered components, but there are big variations depending on its origin. US automobiles tend to have far more sintered components than those produced in Asia.
The use of sintered components is increasing outside the automotive sector, but there is still a huge potential. Parts produced from powder serve special functions
in power tools, white goods, appliances, air-conditioners, computers, lawn movers, locks and pumps. These are just a few examples and the possibilities are endless.
Features and Benefits
More and more designers are choosing sintered components rather than metal parts traditionally manufactured by casting, forging, blanking or machining. Producing parts from powder creates value for small to medium-size components with complex shapes in large volumes.
With sintered components, less is more. Fewer process steps, less machining and less wastage of material and energy in production add up to a solution with lowest total cost.
Sintered components have been increasingly adopted in designs over the past few decades. Their success is mainly due to the significant cost savings derived from net or near-net shape processing compared to other metalworking methods. Machining is generally the largest single cost in metal component production.
Sintered components can offer far more than cost savings. They can be made from tailored materials serving specific purposes and with a design that would be impractical or impossible for other manufacturing technologies.
An iron-based powder mix is the initial material for manufacturing of sintered components. Properties of the final component can be easily tailored by using different alloying elements and other additives. The powder mix also contains a solid lubricant, which is primarily added to reduce friction between the powder mass and surfaces of the compaction tool.
The most common compaction method is axial pressing in a steel or carbide die, usually under pressures of 400-800 MPa. It is possible to press parts with complicated shapes in a single operation and with a high production rate, up to 25 parts per minute. The part receives its predetermined shape after compaction, but not its final dimensions.
Sintering is a heat treatment from which the pressed parts gain strength. The parts are heated in a controlled atmosphere to a temperature that is below the melting point of the main metal. For iron-based alloys this is usually at 1100-1150 °C, for between 15 and 60 minutes, depending on the application. The main mechanisms of sintering are surface and volume diffusion.
The parts are transported on a belt through three furnace zones; dewaxing, where the lubricant is burned off, sintering and cooling. During sintering, a minor dimensional change takes place, which gives the component its final dimensions. Properties of the component can be steered by changing the cooling rate.
Various optional post-sintering process steps are available for sintered components. Hardening operations, for example, are carried out in the same way as for conventional steel, so all treatments applicable to a given alloy are also applicable for sintered material.