A Novel Low-Carbon High-Strength Steel: Processing, Microstructure and Mechanical Properties

Chapter
Part of the Lecture Notes in Mechanical Engineering book series (LNME)

Abstract

A novel alloy steel has been processed through thermo-mechanical controlled rolling with two different finish rolling temperatures (FRT: 850 and 750 °C) followed by air cooling and water quenching. Microstructural investigation using TEM showed that air-cooled steel processed at lowest FRT of 750 °C reveals nano-sized (10–20 nm) complex carbide precipitates of (TiMoV)C which are significant for precipitation hardening in ferrite matrix. Air-cooled steels exhibit 420–440 MPa yield strength and 640–680 MPa ultimate tensile strength along with 20–23% elongation. On the other hand, higher yield strength (900–1000 MPa) and tensile strength (1050–1150 MPa) along with lower 9–11% elongation are attributed to complex precipitation in primarily dislocated lath martensite structure achieved on water quenching. Evaluation of hot ductility, as measured by the reduction of area (RA), reveals that RA decreases in the temperature range of 700 to 850 °C and then rises up to 1100 °C. The maximum achievable ductility of 69% at 1100 °C is related with the stability of austenite at high temperature, whereas minimum ductility (14%) at 850 °C is related with the formation of pro-eutectoid ferrite along the austenite grain boundaries in two-phase (austenite and ferrite) region.

Keywords

Alloy steel Thermo-mechanical controlled rolling Microstructure Mechanical properties 

Notes

Acknowledgements

The authors gratefully acknowledge the financial support provided by TEQIP-II, IIEST, Shibpur, Howrah-711 103, India, in the present investigation.

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Copyright information

© Springer Nature Singapore Pte Ltd. 2018

Authors and Affiliations

  1. 1.Department of Metallurgy and Materials EngineeringIndian Institute of Engineering Science and TechnologyHowrahIndia
  2. 2.R&D DivisionTata Steel LimitedJamshedpurIndia

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