Next Article in Journal
Influences of Al2O3 and TiO2Content on Viscosity and Structure of CaO–8%MgO–Al2O3–SiO2–TiO2–5%FeO Blast Furnace Primary Slag
Previous Article in Journal
Hydrogen Trapping Behavior in Vanadium Microalloyed TRIP-Assisted Annealed Martensitic Steel
Article Menu
Issue 7 (July) cover image

Export Article

Open AccessArticle

Effect of Cooling Rate on Microstructure and Mechanical Properties in the CGHAZ of Electroslag Welded Pearlitic Rail Steel

State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China
*
Author to whom correspondence should be addressed.
Metals 2019, 9(7), 742; https://doi.org/10.3390/met9070742
Received: 5 June 2019 / Revised: 27 June 2019 / Accepted: 28 June 2019 / Published: 30 June 2019
(This article belongs to the Special Issue Microstructure and Properties of Metallic Heat-Affected Zones)
  |  
PDF [8704 KB, uploaded 3 July 2019]
  |  

Abstract

The effect of cooling rate, ranging from 6 to 1 °C/s, on microstructure and mechanical properties in the coarse-grained heat affected zone (CGHAZ) of electroslag welded pearlitic rail steel has been investigated by using confocal scanning laser microcopy (CSLM) and Gleeble 3500 thermo-mechanical simulator. During heating, the formed austenite was inhomogeneous with fractions of untransformed ferrite, which has influenced the pearlite transformation during cooling by providing additional nucleation sites to pearlite. During cooling, at 6 °C/s, the microstructure was composed of martensite and bainite with little pearlite. From 4 to 1 °C/s, microstructures were completely pearlite. Lowering the cooling rate of the CGHAZ from 4 to 1 °C/s increased the pearlite start temperature and reduced the pearlite growth rate. Meanwhile, this increase in pearlite start temperature enlarged the pearlite interlamellar spacing. Alternatively, increasing pearlite interlamellar spacing in the CGHAZ by lowering the cooling rate from 6 to 1 °C/s reduced the hardness and tensile strength, whereas toughness was found unaffected by the pearlite interlamellar spacing. It has been found that a cooling rate of 4 °C/s leads to the formation of pearlite with fine interlamellar spacing of 117 nm in the CGHAZ of electroslag welded pearlitic rail steel where hardness is 425 HV, tensile strength is 1077 MPa, and toughness is 9.1 J. View Full-Text
Keywords: pearlitic rail steel; electroslag welding; coarse-grained heat affected zone (CGHAZ); microstructure; mechanical properties pearlitic rail steel; electroslag welding; coarse-grained heat affected zone (CGHAZ); microstructure; mechanical properties
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Khan, A.R.; Yu, S.; Wang, H.; Jiang, Y. Effect of Cooling Rate on Microstructure and Mechanical Properties in the CGHAZ of Electroslag Welded Pearlitic Rail Steel. Metals 2019, 9, 742.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Metals EISSN 2075-4701 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top