Prediction of Continuous Cooling Transformation Diagrams for Dual-Phase Steels from the Intercritical Region

Abstract

The purpose of the present work is the implementation and validation of a model able to predict the microstructure changes and the mechanical properties in the modern high-strength dualphase steels after the continuous annealing process line (CAPL) and galvanizing (Galv) process. Experimental continuous cooling transformation (CCT) diagrams for 13 differently alloying dual-phase steels were measured by dilatometry from the intercritical range and were used to tune the parameters of the microstructural prediction module of the model. Mechanical properties and microstructural features were measured for more than 400 dual-phase steels simulating the CAPL and Galv industrial process, and the results were used to construct the mechanical model that predicts mechanical properties from microstructural features, chemistry, and process parameters. The model was validated and proved its efficiency in reproducing the transformation kinetic and mechanical properties of dual-phase steels produced by typical industrial process. Although it is limited to the dual-phase grades and chemical compositions explored, this model will constitute a useful tool for the steel industry.

Study of 13Cr-4Ni-(Mo) (F6NM) Steel Grade Heat Treatment for Maximum Hardness Control in Industrial Heats

“…Figure 1 shows the geometry and dimensions of the samples used. Details of the experimental technique are reported elsewhere [14]. These industrial heats were processed through the following treatments: -Homogenizing at 1473 K (1200 °C) for 4 h, followed by preliminary hot forging (HR); -Intermediate stress relief at 700 °C; -Forging (F samples) at 1473 K (1200 °C); -Austenitizing 4 h at 1020 °C followed by oil quenching (OQ) to room temperature.…”

“…Figure 1 shows the geometry and dimensions of the samples used. Details of the experimental technique are reported elsewhere [14]. Figure 1.…”

Strain Hardening Behavior Prediction Model For Automotive High Strength Multiphase Steels

“…This use of mechanical properties instead of process parameters has been chosen because in this way, it has been possible to treat all data (both for DP steels and TRIP ones) together even if they are relative to different thermal cycles with different process parameters. Moreover, several software already exist for the prediction of mechanical properties of multiphase steels using as input chemical compositions and process parameters.…”

Effects of Finish Cooling Temperature on Tensile Properties After Thermal Aging of Strain-Based API X60 Linepipe Steels

“…[5,6] Many studies have been conducted to form large amounts of cementite in linepipe steels and to reduce the number of carbon atoms in ferrite because carbon atoms are the main factors for the strain aging phenomena. [7][8][9][10][11][12] The finish cooling temperatures strongly affect the formation of secondary phases, such as cementite and martensite-austenite constituents (MA). [13] The microstructures of linepipe steels are dependent on their chemical compositions and cooling and rolling conditions, and are classified according to the morphological categories.…”