Dynamic properties of nitrogen alloyed 1045 iron-carbon-steel

Abstract
A new high-pressure melting process enables nitrogen addition to ferritic Fe-C-alloys. A commercial-grade steel alloy, 1045, was cast under elevated nitrogen pressure, resulting in solid solution (austenite, ferrite, and martensite) and a porous microstructure. The retained high nitrogen concentrations in the Fe-C-alloy resulted in a substantial improvement in both quasistatic and dynamic compression strength. Using Planar-Plate-Impact-Technique (PPI) together with a VISAR and Split-Hopkinson-Pressure-Bar-Technique (SHPB) the dynamic properties have been determined in the strain rate regime 10 ³ s ^-1-10⁶ s ^-1. With the PPI-Technique the Hugoniot-Elastic-Limit and the spall strength as well as the U -u and the stress-strain relation have been determined. An unusual strong slope of the U -u -relation and a very low spall strength have been observed for both nitrogen contents. In this paper, the properties of the Fe-C-N alloy with these two nitrogen contents will be compared to those of nitrogen alloyed austenitic steels.