Specializing in Corrosion Prevention

            David Schalcosky

            Eric Parish

            Shaun Nagy

    Based out of a large manufacturing facility in St. Marys PA, Keystone Powdered Metal Company produces a variety of powdered metal parts for a range of applications.  Rust in the powdered metal industry is a major problem and results in significant scrap costs.  In order to combat rust, in turn lowering scrap costs, SPN Engineering must analyze commercially available rust inhibitors and develop experiment(s) to determine the preventative power of the various inhibitors.  SPN has researched and assessed the state of the art in rust preventatives and inhibitors for ferrous-based parts.  SPN has tested  candidates identified in the previous step in efforts to determine rust protection.

·            Complete research to determine the state of the art in rust inhibitors

·            Design a suitable experiment to evaluate top inhibitor candidates

The specifications for the rust inhibitor are straightforward.  The inhibitor must withstand 100% humidity and a harsh manufacturing plant environment.  The PM parts may sit on the plant floor for lengths of time; therefore the inhibitor may experience extreme humidity, chlorine rich air, dust and oil residue from the plant machinery, and heat from the sintering furnaces.  The desired length of protection for the inhibitor is six months.  The parts are mass-produced but may sit in warehouses or on shipping docks for months at a time before the customer needs them.

The inhibitor must be easily applicable to parts in a variety of different finishing processes.  The first rust occurs immediately after the sintering process; this is where the inhibitor must first be applied.  From there, the parts go through several different types of finishing processes.  For the parts that are deburred, washed, and dried, it is desirable to have a water-soluble inhibitor that can withstand temperatures of up to 275°F.  The parts that are machined will need a re-application of the inhibitor after machining.

SPN Engineering used a closed container test apparatus.  The apparatus was constructed from a 15”x14”x12” nine gallon clear plastic chamber, with a coated wire metal rack for holding the part.  The rack was four inches in height and allowed for the P/M part to be held sufficiently above the mixture.  See figure below for clarity.

 The mixture used to accelerate the corrosion was as follows:

The test chamber was set up in room 101 in Engineering Unit C.  Temperature and humidity were monitored while the test was run.  An external 1500 Watt electric heater was also used to accelerate corrosion.  Three P/M parts were tested at once, each with different percentage of inhibitor applied.  This allowed SPN in compare results from three different percentages under one condition.

The test parts supplied by Keystone powdered metal were indicative of many products Keystone produces.  The parts supplied were MPIF FC-0208 sintered powdered metal parts.  They are composed of 97.2% Fe, 2%Cu, and 0.8%C.

    SPN Engineering’s exhaustive research has yielded a wide variety of inhibitors available for use by Keystone Powdered Metal.  Preliminary testing has also give SPN insight into the effectiveness of rust inhibitors.  Based on testing SPN has concluded that the rust inhibitors tested provided beneficial rust preventing power.  The inhibitor coated parts provide a much longer time.

SPN Engineering recommends that Keystone Powdered Metal continue examine the top inhibitor candidates identified by SPN for use in their processes.  SPN suggests that Keystone continue with the test scheme devised by SPN to evaluate the top inhibitor candidates.  Additionally, SPN recommends that Keystone examine the use of vapor phase inhibitors for use during part storage and shipping.

For more information, or any questions contact any group member

David Schalcosky(dcs164@psu.edu):

Eric Parish(emp133@psu.edu):

Shaun Nagy(smn122@psu.edu):