Kobe Steel Ltd reports that it will expand production capacity of its iron and steel powders at its Takasago steel powder plant in Hyogo, Japan by 15% by September 2011. The expansion will increase monthly capacity to 7,500 tonnes or 90,000 tonnes/year.
Kobe Steel also reported that it will be increasing production of its segregation-free Segless grade which is an alloy powder of iron mixed with graphite, copper and lubricant used to produce high density PM parts. The company has introduced a newly developed KPA lubricant for this grade which is said to have better powder flow properties at the compaction stage and better ejection from the die. This combination makes it possible to reduce the lubricant KPA content in the powder mix without increasing ejection pressure, and to produce PM parts similar in density to those produced by die wall lubrication and warm compaction.
Reports on advances in other steel powder grades were published in the company’s Kobe Steel Engineering Reports (August 2010) and at the PM2010 World Congress in Florence in October 2010. Included is a new low prealloyed steel powder grade designated 44FH30 containing 0.3wt% Mo which is said to have compressibility equivalent to pure iron powder and provides tensile strength greater than 600 MPa. The high fatigue strength of 44FH30 is due to the precipitation of bainite at the boundary of the powder particles.
Another development involves new hybrid epoxy/polyester based thermo-setting resin (TSR) binder and an epoxy-based ambient temperature reactive resin (ATR) binder used to increase the green strength in PM compacts. The TSR binder is used for combination of (1) compaction and curing and (2) warm compaction to achieve the high green strength prior to green machining. The ATR binder does not need curing and is used for room temperature compaction. The increased green strength in all three cases allows the machining of unsintered (green) compacts at extremely low forces or stresses, and is expected to overcome the problems of machining high strength and high hardness sintered and heat treated PM parts. Both TSR and ATR binders are in a fine dry-powder state and give satisfactory powder flowability.