Towards industrial applicability of (medium C) nanostructured bainitic steels
Excellent combinations of strength and toughness can be obtained from high-carbon nanobainite, but this requires high levels of alloying and long heat treatments. This project will develop very fine bainitic – austenitic steels more cost effectively from leaner medium carbon alloys using shorter processing times via thermomechanical ausforming. Tensile strengths above 1600MPa are aimed at to give hot rolled steels with enhanced wear resistance combined with good toughness. Suitable compositions and processing parameters will be developed using modelling and physical simulation. Trial products will be produced and tested using laboratory rolled materials, and recommendations for full-scale production parameters will be made.
Contribution: OULU will contribute to the physical simulation of phase transformation characteristics (construction of CCT and TTT diagrams) and constitutive flow stress behaviour for a part of the steel compositions, besides conducting grain growth and recrystallization kinetics studies on select steels chosen for TMCP and LT-TMCP processing. Oulu will contribute to both Gleeble and laboratory rolling simulations of select test materials and property testing besides limited microstructural analysis and simulating phase transformation. Plastic deformation in rolling will be simulated and coupled with the microstructure model. The results from different work packages will be incorporated into a model of actual thermomechanical processing conditions, including rolling force and power, and cooling water requirements.
The main objectives and deliverables of this project are:
- Design of medium carbon compositions which would be suitable for ausforming and transformation to high-strength, tough nanostructured bainitic-austenitic microstructures.
- The assessment of different TMCP and LT-TMCP schedules on the microstructures and mechanical properties.
- Identification of relevant microstructural constituents, evolution, refinement, and their relationships with the measured properties.
- Selection of appropriate compositions with processing parameters viable for industrial full-scale production.
Duration: 1.7.2016 -
Contact person: Dr Mahesh C. Somani
Partners: ThyssenKrupp Europe, CENIM-CSIC, UO, OCAS
Last updated: 28.2.2019