Metal Powder Production

Metal powders are used in a variety of manufacturing processes, including sintering, thermal spray surface coating and welding, and the fine powders required are produced using one of four main processes including Water Atomisation [1]. This technique is employed by ECKA Granules, one of the leading international producers of metal powders.

Their atomisation lines have the capacity to produce in excess of 3,000 tonnes per annum of Nickel, Cobalt and Stainless Steel powders in the most modern facility in their market. In order to keep its competitive edge, the company is constantly looking for ways to improve production and at the end of 2011 they invested in a new high-pressure water system incorporating three Cat Pumps model 3545 plunger pumps.

“We needed a solution that would give us greater efficiency and improved productivity without compromising on product quality,” says Andrew Baker of ECKA Granules. “Cat Pumps impressed us with their recommendations and produced a cost-effective package that met our brief. After more than six months of operation, we have seen the improvement in productivity that we wanted to achieve, and the pumps have provided the service and reliability that we required.”

ECKA Granules’ existing high pressure pumping system relied on two pumps operating in tandem and whilst these were effective in generating the higher pressures required for producing fine powders, when run at only 70 bar for making larger granules, they were inefficient.

In order to achieve higher product throughput volumes, it was decided to introduce Cat Pumps triplex plunger pumps as these would give the pressure and flow-rates required. The three model 3545 pumps provide a combined flow rate of 405 L/m at up to 70 bar and their smooth pulse-free performance ensures that the pressure at the spray nozzles in the atomising chamber is constant. Any variation would impact on the size of the granules.

The batch production process for making granules and powders involves melting metals in 500 kg induction furnaces, taking over three hours and operating 24 hours a day. The liquid metal alloy is then poured from its crucible into a water-cooled chamber to produce the required size of liquid droplets. Inside the chamber the metal droplets are quenched to solid granules by water and air, or they fall onto a water-cooled metal plate, and by controlling the process parameters the shape of the granules can be varied from needle, irregular to spherical. The constant availability at the spray nozzles of water to quench the molten metal is essential to the whole process. The higher the water pressure used in the atomisation process, the finer the granules or powders. This places a high level of importance on the water supply system and the pumps involved. It is also a hostile, unforgiving working environment. This was the first time that ECKA have used triplex pumps and to date, their experience has more than measured up to expectations. They purchased the Cat Pumps model 3545 as it has a reputation for operating reliably in harsh conditions and providing the high levels of performance that the powder manufacturing industry requires.

[1]. Powder Metallurgy on Wikipedia