Powder Metallurgy Sintering Considerations

Pusher Furnace for Powder Metallurgy Sintering

While the topic of the “hydrogen economy” has heated up in recent years, there is still no conclusive research showing that hydrogen production for fuel is cost effective in the long run.

But in the world of industrial furnaces, hydrogen has been a heated topic for fifty years (pun intended…)

Pure hydrogen gas (H2) is one of the most effective non-air atmospheres for high-temperature sintering (i.e. for thermal powder fusing to form solids at or near their melting point). Hydrogen Furnace Sintering is used widely as part of many powder metallurgy (PM) processes to create parts of extremely accurate size and uniformity. Stainless steel is common, but a other high-performance alloys, such as tungsten carbide and other alloys, also require high-temperature sintering in hydrogen. Even certain ceramic/metallic compositions use a hydrogen based sintering process to create a specialized parts with very specific physical properties.

These processes typically require a sintering temperature of at least 1300C in pure hydrogen and temperatures of up to 1600C are not unheard of when specialized alloy’s are involved.

The most common furnaces selected for powder metallurgy processes in a production environment are continuous furnaces or “pusher” furnaces owing to their high throughput. In lower temperature PM processes, belt furnaces are also used but these furnaces are not feasible at the high end of the sintering temperature range.

Another key design element for powedered metallurgy sintering is the quality of the refractory used in the furnace. It must be non-reactive in pure hydrogen or mixed hydrogen atmopheres and for this reason high alumina or alumina-silicates are typically chosen for the refractory material. In addition, the hot-face lining in the hot zone must be a high-purity alumina with almost no silica. Zone temperatures in pusher furnaces are held constant so thermal shock issues are avoided as well.

Our solution to the Power Metallurgy Sintering Problem

Furnaces like the CM-400 Series embody the key elements of refractory design and continuous furnace operation that provide the hydrogen sintering environment at temperatures up to 2200C. These furnaces are designed with zirconia insulating brick and tungsten rod elements that are non reactive and can last for many years without incident.

The 400 series is also designed for heavy loads and the open hearth and exposed element design provides for processing of large amounts of material while maintaining temperature uniformity.

And finally the CM-400 series can operate using hydrogen, dissociated ammonia, forming gas or any other reducing atmosphere compatible with refractory metal heating elements can be employed.

CM Furnaces In Powder Metallurgy.

Furnaces like the CM 300, CM400 or our CM-1500 series for batch processing have been the furnaces of choice for MIM sintering processes for decades. Some of the other processes we are deployed into include:

·         Refractory Metals ·         Powder Metallurgy ·         Technical Ceramics
·         PM Sintering ·         Metallizing Processes ·         Heat Treatment
·         Annealing ·         Brazing ·         Reducing Processes
·         Firing and Co-Firing ·         Debinding ·         Glass Melting

 

For over 70 years CM furnaces has provided industrial furnace solutions in applications where quality matters.

Call CM furnaces today for more information on how we can help.