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Please use this identifier to cite or link to this item: http://repository.iitr.ac.in/handle/123456789/12658
Title: Continuous cooling transformation behavior in the weld coarse grained heat affected zone and mechanical properties of Nb-microalloyed and HY85 steels
Authors: Kumar S.
Nath S.K.
Kumar V.
Published in: Materials and Design
Abstract: Continuous cooling transformation (CCT) diagrams were determined for weld simulated coarse grained heat affected zone (CGHAZ) of Nb-microalloyed and HY 85 steels using a Gleeble®3800 thermo-mechanical simulator. Samples were heated to a peak temperature of 1573K (1300°C) and cooled at different cooling rates from 0.5K/s to 120K/s. Microstructures, hardness, and impact toughness at 223K were determined corresponding to simulated samples of weld CGHAZ thermal cycles. Transformation temperatures AC3, AC1, Bs, Bf, Ms, and Mf were also determined using dilatometric analysis. At slow cooling rates pro-eutectoid ferrite and pearlite were observed in Nb-microalloyed steel and a mixture of bainitic ferrite and granular bainite was observed in HY 85 steel but no pro-eutectoid ferrite was observed. At moderate cooling rates, only bainite was observed in both the steels. At high cooling rates, lath martensite was observed for both the steels. A strong dependence of prior austenite grain size on mechanical properties has been found. A prior austenite grain size of approximately 30μm (80K/s) has shown impact toughness more than 100J and 198J for Nb-microalloyed steel and HY85 steel samples respectively. Based on microstructures, hardness, impact toughness, and transformation temperatures, CCT diagrams for the weld CGHAZ region were determined. © 2015 Elsevier Ltd.
Citation: Materials and Design (2016), 90(): 177-184
URI: https://doi.org/10.1016/j.matdes.2015.10.071
http://repository.iitr.ac.in/handle/123456789/12658
Issue Date: 2016
Publisher: Elsevier Ltd
Keywords: CCT diagram
Phase transformations
Steels
Toughness
Weld HAZ simulation
Weldability
ISSN: 2641275
Author Scopus IDs: 57209548009
7102759700
57203774517
Author Affiliations: Kumar, S., Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
Nath, S.K., Metallurgical and Materials Engineering Department, Indian Institute of Technology Roorkee, Roorkee, 247667, India
Kumar, V., R and D Centre for Iron and Steel, RDCIS, SAIL, Ranchi, Jharkhand, 834002, India
Funding Details: Thermo-mechanical simulator Gleeble®3800 has been procured from the FIST grant ( SR/FST/ETI-216/2007 Dated 06.02.2008) of DST New Delhi.
Corresponding Author: Nath, S.K.; Metallurgical and Materials Engineering Department, Indian Institute of Technology RoorkeeIndia; email: indiafmt@iitr.ac.in
Appears in Collections:Journal Publications [MT]

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