Computer modeling of the critical steps of the powder metal manufacturing process (compaction, sintering, and heat treatment) has been conducted within the university and research community for about 15 years. Most of the studies concentrated on the compaction issues. However, no commercial compaction code has been released or offered to the PM community since the program sponsored by CTC in the 1990s. A few of the major parts producers have developed their own in-house codes, though the use of these compaction simulations remains limited. The European community undertook a validation project a few years ago and demonstrated that at least one research organization, believed to be Fraunhofer, was able to predict green density very well. The prediction of green cracks was still an open question. More recently CetaTech, under the encouragement of CPMT, was able to use their computer model to duplicate the excellent European results.

Simulation of the sintering process began at Penn State in the past few years, using the Master Sintering Curve concept and has been applied to refractory metal systems. Similarly a heat-treat model developed for wrought steels by DCT is now being modified by researchers at WPI for application to porous materials.

A totally new approach to process modeling is now taking place at Mississippi State University under the guidance of Dr. Mark Horstmeyer at the Center for Automotive Vehicle Systems (CAVS). A three-year program sponsored by USCAR and supported by CPMT was initiated in late 2004 to use the “atoms to autos” approach and apply it to a powder metal system. Two PM parts were selected for the simulation—a main bearing cap (MBC) and a high-performance gear.    

The goal of this project is to validate this new model for a typical PM part and demonstrate its ability to accurately predict the response of the PM part under the complex loading conditions found in automotive systems.     

Status

A preliminary program plan was prepared by the researchers at CAVS and approved by the USAMP committee. A test matrix was proposed, reviewed, and approved. These tests will develop the data needed for the computer simulations as well as the performance response of the PM steel (FC-0205). Commercial powders were used to manufacture the test materials, followed by sintering at suitable commercial locations.  Metaldyne has volunteered to serve as the industry “test bed” for the main bearing cap portion of the program.  A series of tests were run at Penn State University to characterize the base powder compaction response.  In addition a second series of verification test samples were compacted at Cincinnati Inc., reflecting a three level component geometry that will be used to verify the model before applying it to the main bearing cap geometry.  Since the beginning of 2007 Metaldyne has supplied powder, green and sintered MBC sample parts and several hundred test specimens that will be used to develop performance data.  The compaction portion of the model is projected for completion by the end of the second quarter and the sintering portion by the end of the third quarter 2007.  Performance simulations and part response predictions will conclude the program by year end 2007.