TRIP-assisted CMnSiAl steels with a fully martensitic initial microstructure have been studied in order to investigate the effect of partial substitution Si by Al. The steel was fabricated casting sand mold, hot forged, homogenizing, rolling, cold intercritical annealing, and finally, an isothermal bainitic treatment. During annealing at 1023 K (750 °C) for 420 s, matrix consisting 50% proeutec...

Abstract The bainitic ferrite plate thickness is the main parameter that controls strength of this type microstructures. Such has been proved to mainly depend on austenite yield strength, driving force for transformation and temperature. However, no research focused how these parameters evolve throughout evolution can affect outcome. In study, thermal thermomechanical treatments have performed ...

The current study reports in situ TEM observations of the growth bainitic ferrite an Fe-0.3C-3Mn-1.5Si-0.15Mo steel held isothermally at 300 °C with a higher spatio-temporal resolution than previous studies. Significant variations were found lengthening rate, highest being excess 30,000 nm.s−1 while more common rates 10–1000 provided quality observations. Both sheaves visible sub units and indi...

The successive ferrite (α) + pearlite (P) transformations from austenite (γ) have been modeled to predict the intervention of bainite in as-forged medium-carbon manganese steels. The kinetics of the diffusional transformations were calculated based on the classical nucleation-growth theory coupled with the CALPHAD multi-component thermodynamics. The description of growth rate of proeutectoid-α ...

The response of a strong bainitic–steel to tempering at high temperatures is investigated, because a softened state is sometimes necessary during the manufacture of engineering components, prior to the final heat–treatment which hardens the material. Thermodynamic calculations conducted to determine the maximum temperature at which the steel could be annealed without forming austenite were foun...

In this research, the 600 MPa acid resistant steel was used as flash butt welding base material, to study effect of different upset allowance on microstructure and mechanical properties joints. The results can be obtained follows: with increase allowance, it has a significant elongation, ferrite content in heat affected zone increases, joint strength first increases then slowly decreases. When ...

Abstract In the present work different approaches to improve mechanical properties of a resistance spot welded 1200 MPa transformation induced plasticity-aided bainitic ferrite steel are evaluated. An extension welding time results in coarsening microstructure outer fusion zone and maximum force derived by cross tension strength test did not significantly. A temper pulse after long cooling lead...

Abstract Heavy plate steels with bainitic microstructures are widely used in industry due to their good combination of strength and toughness. However, obtaining optimal mechanical properties is often challenging the complex multiple phase constitutions caused by different cooling rates through thickness. Here, both conventional advanced microstructural characterization techniques which bridge ...

In this work, three low-carbon bainitic steels, with different Mo contents, were designed to investigate the effects of Mo addition on microstructure and mechanical properties. Two-step cooling, i.e., initial accelerated cooling and subsequent slow cooling, was used to obtain the desired bainite microstructure. The results show that the product of strength and elongation first increases and the...