Microstructural and mechanical properties of ultra-high-strength dual-phase steel produced by ultra-fast cooling

Abstract

In the present study, grain refinement of Fe–Si–Mn–Nb–B steel was achieved by high reduction hot rolling. Through the following ultra-fast cooling (UFC) and relaxation process, martensite-ferrite complexes with soft phase embedded in the hard phase were prepared. Extremely tiny ferrite grains significantly increased the toughness of the test steel, a large number of big-angle grain boundaries existing in fine martensite lath bundles effectively improved the strength and the strain hardening ability of the investigated material. The test steel with a relaxation time of 6 s shows the best comprehensive performance with a tensile strength of 1473 MPa, an elongation of 15.0%, a low yield ratio of 0.72 and a product of strength and elongation (PSE) of 22.10 GPa%.

Processing, microstructure adjustments, and mechanical properties of dual phase steels: A review

“…The cooling rate is the final factor of the intercritical annealing of DP steels [194,195]. The cooling rate must be sufficiently high for triggering the austenite to martensite transformation.…”

Transformation Mechanism and Precipitation Behavior of Nanoscale Cementite in Carbon Steels during Ultrafast Cooling

“…Over the last 20 years, ultrafast cooling (UFC) technology, with a high cooling capacity and high precision control, has been successfully developed and applied for diverse steel applications, such as shipbuilding, pipelines, and machinery. [10][11][12][13][14][15][16][17][18] It also The precipitation behavior and transformation mechanism of cementite in low-and medium-carbon steels (0.04-0.5% C) after hot rolling are studied using ultrafast cooling (UFC) technology. The results show that the carbon concentration and stop-cooling temperature are the primary factors influencing the precipitation behavior of nanoscale cementite.…”