Kobe Steel Ltd. announced plans to invest approximately $162.3 million (¥1.8 billion) to increase the production capacity of its steel powder plant at Takasago, Hyogo Prefecture, by 14,000 mt to 110,000 mtpy. The expansion, in western Japan, will be completed during Q2 2021.
Specifically, Kobe Steel indicated it will install another reduction furnace to achieve higher treatment temperatures for steel powders than the current furnaces. And, it will install another mixer to increase production capacity of SEGLESS®, one of its metal powder series. SEGLESS products will comprise 60,000 mtpy (from the current 40,000 mtpy) of the new total capacity.
The SEGLESS KP and KS series having high compressibility and machinability, which contribute to high strength.
Metal powders are produced by atomizing the selected grade and then crushing or grinding the resulting material to achieve the preferred grain size.
Kobe Steel has been producing steel powder since 1968, and was the first in Japan to introduce an atomization process in which high-pressure water is sprayed onto molten metal, turning it into a powder. The process results in steel powders of high purity, high compressibility, and high density, according to Kobe Steel.
Describing its powder manufacturing process, Kobe Steel reported that graphite is mixed with the powdered steel to improve the strength of sintered parts: graphite has a low specific gravity and its particle size is small, resulting in variation in the composition of the part. To improve this condition, Kobe Steel’s SEGLESS (i.e., "segregation free") treatment of the powder allows the steel and graphite to bond more effectively. This mixture of steel and graphite is then heat-treated in a reduction furnace.
Powdered metals are formed into finished parts by blending the material to the determined metallurgical composition, then compacting the mixture into a die form, and sintering. Powder metal processes include powder forging, isostatic pressing, and metal injection molding. Additive manufacturing via direct metal-laser sintering or stereolithography are emerging technologies in this area, too.
Subsequent to forming and sintering, the finished parts may be heat-treated to achieve the necessary mechanical qualities.
Kobe Steel noted that its steel powders are used mainly to form automotive parts, including engine and transmission components. It estimated that it holds almost 50% of the domestic market for such parts, making it the Japanese market leader.
In addition to steel powder for powder metallurgy, it also produces steel powder for remediating contaminated soil and ground water, called ECOMEL™; a magnetic steel powder called MAGMEL™ for use in motors and reactors; and other powders for use in hand warmers and deoxidants.