SBIR-STTR Award

Unanticipated distortion during the heat treatment of precision steelparts adds significant cost for both commercial and defense suppliers. A collaborative project managed by the National Center for Manufacturing sciences has resulted in the development of a multiphase internalstate variable material model and comprehensive phase transformation kinetics models that accurately describe the mechanical and metallurgical response of steel alloys to carburization and immersion quench hardening processes. Other significant progress was made in process characterization and in describing heat transfer between the workplace and environment. This capability will be extended to include fixtured and press quenching. A commercial software tool to predict dimensional change, residual stresses, metallurgical phase distribution and volume fraction, and hardness of both through-hardened and carburized steel parts that have been heat-treated will be developed. The user interface of the software will be a customized version P3/PATRAN that contains dataforms specific to the heat treat industry. The software will producefinite element models to be solved using ABAQUS and it's user definedmaterial subroutine capability. Included in this software developmentprogram is the specification of the material and process data required for simulation and the methods for determining these data.

Benefits:
The commercial application resulting from this project is a software tool to sell to heat treaters. The benefit to them is reduced process cost.

Phase I of this project has resulted in demonstrating the feasibility of developing software to predict distortion of heat treated components. An alpha version of DANTE (Distortion Analysis for Thermal Engineering) was developed to predict dimensional change, residual stresses, metallurgical phase distribution, phase volume fraction, and hardness for through-hardened and carburized steel parts. This software is based on the results of a collaborative project managed by NCMS. The technical underpinnings of DANTE include a multiphase internal state variable material model developed at Sandia National Laboratory and comprehensive phase transformation kinetics models for guenching developed at Colorado School of Mines. The user interface of the software is a customized version PATRAN that contains menus specific to heat-treating. The software produces finite element models to be solved using ABAQUS and user defined material subroutines UMAT, UMATHT and FILM. In Phase II, the software capability will be expanded to cover most commercial ferrous heat treat process steps, including press quenching. Material data, including Pyrowearr 531 will be added to the material database, a formal training program will be developed and implemented, new DANTE users will be added, Users Group activities will be expanded, and a commercialization strategy will be implemented.

Benefits:
This commercial software package will be used by heat treaters and designers to reduce costs associated with part distortion due to heat treatment, as well as to predict resulting part hardness and residual stress.

Keywords:
Heat Treat Distortion Hardness Prediction Free Ouench Simulation Heat Treat Simulation Residual Stre