The effect of continuous and isothermal cooling on the mechanical properties of a low carbon bainitic steel

Date

2023-7-04

Author

Kaderli, Esra

Metadata

Show full item record

This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.

Item Usage Stats

170
views

71
downloads

Cite This

Steels with a bainitic microstructure offer great possibilities for highly stressed forged components. Different combinations of mechanical properties can thereby be adjusted in these steels, dependent on the morphology of the bainitic phase. Also, the bainitic structure obtained by continuous cooling offers an advantage by eliminating the heat treatment step. The aim is to obtain the bainitic microstructure without using complicated heat treatment procedures. In this study, a low carbon bainitic forging steel is studied with different Mo and Si amounts. This morphology is compared with the bainite obtained by isothermal treatments just above the Ms temperature. Morphologies were investigated by optical and scanning electron microscopy. Needle-like and granular bainite are observed on continuous cooling specimens whereas needlelike bainite morphology is observed with isothermal cooling. Mechanical properties were investigated by hardness test, tensile test, charpy impact test, and retained austenite content was determined by XRD measurement. As Si content increases retained austenite amount decreases slightly. A high-strength (>900MPa) steel with adequate ductility was obtained with continuous cooling according to mechanical test results.

Subject Keywords

Bainitic steel, Retained austenite, Continuous cooling, Isothermal transformation, Bainite

URI

https://hdl.handle.net/11511/104795

Collections

Graduate School of Natural and Applied Sciences, Thesis