Prediction of stainless steel performance after forming and finishing (PRESSPERFECT) : final report

This project compares 3 different production routes of high strength stainless steels precision parts, including the heat treatment on accuracy of a demonstrator product and tries to make the production route predictive by numerical modelling using FEM models and building the necessary constitutive models and implement them. The chosen combination of material and heat treatment are: 1) Martensitic stainless steel (AISI 420) & heat treatment; 2) Austenitic stainless steel (EN 1,4369) & nitro carburising; 3) Precipitation hardening stainless steel (ASTM A693) & precipitation hardening and simultaneous nitro carburising. Based on the selected routes, research has been done to measure all the relevant properties for plastic deformation and the heat treatments of these steels and to look what is already available in literature. In parallel, Physical based models were developed, based on existing models and extended them to the necessary level to calculate the plastic deformation and heat treatment. The developed models are implemented in the commercially available software package MSC-MARC. Finally a demonstrator product was designed, tooling was ordered to produce the demonstrator products in small quantities and to measure the accuracy of theses demonstrator products after stamping and the heat treatment. The models are used to simulate the production chain and to check how predictive these models are and to validate the models by the demonstrator products. In the last phase of the project one of the routes (AISI 420) was improved by changing the material processing route at the steel supplier to enable a more accurate demonstrator.