Study on mechanical properties and microstructure of DP590 steel with different annealing process

Annealing process is critical to mechanical properties and microstructure of DP steel. For steel with strength grade 590MPa, experiments different combinations intercritical annealing temperature over-aging were carried out during annealing. The tensile tests the final products nanohardness phases made, microstructures analyzed. results indicated that higher was favorable volume fraction martensite lower C density. ultimate increased monotonously increasing. Higher over aging would make islands be partially resolved carbides precipitate, which made martensite, resulted in martensite. revealed rules could provide important guide control material by manipulating process.