Effect of welding heat input on microstructure and mechanical properties of simulated HAZ in Cu containing microalloyed steel

Amer E. Amer; Min Y. Koo; Kyong H. Lee; Sang H. Kim; Soon H. Hong

doi:10.1007/s10853-009-4074-7

Effect of welding heat input on microstructure and mechanical properties of simulated HAZ in Cu containing microalloyed steel

Amer E. Amer, Min Y. Koo, Kyong H. Lee, Sang H. Kim, Soon H. Hong

Research output: Contribution to journal › Article › peer-review

63 Scopus citations

Abstract

The influence of weld thermal simulation on ICGC HAZ microstructure and mechanical properties of Cu containing Nb-Ti-microalloyed steel has been investigated. Low heat input of 0.7 kJ/mm (simulated fast cooling of Δt _8/5 = 5 s) and high heat input of 4.5 kJ/mm (simulated slow cooling of Δt _8/5 = 61 s) were used to generate double-pass thermal cycles with peak temperatures of 1350 and 800 °C, respectively. The microstructure after high heat input mainly consisted of polygonal and quasi-polygonal ferrite (QF) grains with certain amount of acicular ferrite, whereas, after the low heat input, microstructure mainly consisted of lath or elongated bainite-ferrite, QF and M-A constituents. The size of ferrite grains decreased and volume of M/A constituents increased with fast cooling rate. The precipitation characteristics were found to be similar in both cooling rates. However, the precipitation of Cu-related phases was promoted by slow cooling rate. By fast cooling rate, the investigated steel exhibited an increase in hardness from 187_HV to 197_HV. Consequently higher yield strength with considerable loss in the (-10 °C) CTOD fracture toughness (δ_{fast cooling} = 0.86 mm and δ_{slow cooling} = 1.12 mm) were demonstrated.

Original language	English
Pages (from-to)	1248-1254
Number of pages	7
Journal	Journal of Materials Science
Volume	45
Issue number	5
DOIs	https://doi.org/10.1007/s10853-009-4074-7
State	Published - Mar 2010
Externally published	Yes

Funding

Acknowledgements The authors are grateful to the management of POSCO for providing research materials of this investigation and for the permission to publish the article. In addition, we are in debt to the Post Doc. Fellowship program of the KOSEF, Republic of Korea, for sponsoring the visit of Dr. A.E. Amer, Cairo—Egypt at the Korea Advanced Institute of Science and Technology (KAIST)—Department of Materials Science and Engineering.

Funders	Funder number
Department of Materials Science and Engineering
Korea Science and Engineering Foundation
Korea Advanced Institute of Science and Technology

Access to Document

10.1007/s10853-009-4074-7

Cite this

@article{1a8d59f69a0a431f9806d8e143aa3610,

title = "Effect of welding heat input on microstructure and mechanical properties of simulated HAZ in Cu containing microalloyed steel",

abstract = "The influence of weld thermal simulation on ICGC HAZ microstructure and mechanical properties of Cu containing Nb-Ti-microalloyed steel has been investigated. Low heat input of 0.7 kJ/mm (simulated fast cooling of Δt 8/5 = 5 s) and high heat input of 4.5 kJ/mm (simulated slow cooling of Δt 8/5 = 61 s) were used to generate double-pass thermal cycles with peak temperatures of 1350 and 800 °C, respectively. The microstructure after high heat input mainly consisted of polygonal and quasi-polygonal ferrite (QF) grains with certain amount of acicular ferrite, whereas, after the low heat input, microstructure mainly consisted of lath or elongated bainite-ferrite, QF and M-A constituents. The size of ferrite grains decreased and volume of M/A constituents increased with fast cooling rate. The precipitation characteristics were found to be similar in both cooling rates. However, the precipitation of Cu-related phases was promoted by slow cooling rate. By fast cooling rate, the investigated steel exhibited an increase in hardness from 187HV to 197HV. Consequently higher yield strength with considerable loss in the (-10 °C) CTOD fracture toughness (δfast cooling = 0.86 mm and δslow cooling = 1.12 mm) were demonstrated.",

author = "Amer, {Amer E.} and Koo, {Min Y.} and Lee, {Kyong H.} and Kim, {Sang H.} and Hong, {Soon H.}",

year = "2010",

month = mar,

doi = "10.1007/s10853-009-4074-7",

language = "English",

volume = "45",

pages = "1248--1254",

journal = "Journal of Materials Science",

issn = "0022-2461",

publisher = "Springer",

number = "5",

}

TY - JOUR

T1 - Effect of welding heat input on microstructure and mechanical properties of simulated HAZ in Cu containing microalloyed steel

AU - Amer, Amer E.

AU - Koo, Min Y.

AU - Lee, Kyong H.

AU - Kim, Sang H.

AU - Hong, Soon H.

PY - 2010/3

Y1 - 2010/3

N2 - The influence of weld thermal simulation on ICGC HAZ microstructure and mechanical properties of Cu containing Nb-Ti-microalloyed steel has been investigated. Low heat input of 0.7 kJ/mm (simulated fast cooling of Δt 8/5 = 5 s) and high heat input of 4.5 kJ/mm (simulated slow cooling of Δt 8/5 = 61 s) were used to generate double-pass thermal cycles with peak temperatures of 1350 and 800 °C, respectively. The microstructure after high heat input mainly consisted of polygonal and quasi-polygonal ferrite (QF) grains with certain amount of acicular ferrite, whereas, after the low heat input, microstructure mainly consisted of lath or elongated bainite-ferrite, QF and M-A constituents. The size of ferrite grains decreased and volume of M/A constituents increased with fast cooling rate. The precipitation characteristics were found to be similar in both cooling rates. However, the precipitation of Cu-related phases was promoted by slow cooling rate. By fast cooling rate, the investigated steel exhibited an increase in hardness from 187HV to 197HV. Consequently higher yield strength with considerable loss in the (-10 °C) CTOD fracture toughness (δfast cooling = 0.86 mm and δslow cooling = 1.12 mm) were demonstrated.

AB - The influence of weld thermal simulation on ICGC HAZ microstructure and mechanical properties of Cu containing Nb-Ti-microalloyed steel has been investigated. Low heat input of 0.7 kJ/mm (simulated fast cooling of Δt 8/5 = 5 s) and high heat input of 4.5 kJ/mm (simulated slow cooling of Δt 8/5 = 61 s) were used to generate double-pass thermal cycles with peak temperatures of 1350 and 800 °C, respectively. The microstructure after high heat input mainly consisted of polygonal and quasi-polygonal ferrite (QF) grains with certain amount of acicular ferrite, whereas, after the low heat input, microstructure mainly consisted of lath or elongated bainite-ferrite, QF and M-A constituents. The size of ferrite grains decreased and volume of M/A constituents increased with fast cooling rate. The precipitation characteristics were found to be similar in both cooling rates. However, the precipitation of Cu-related phases was promoted by slow cooling rate. By fast cooling rate, the investigated steel exhibited an increase in hardness from 187HV to 197HV. Consequently higher yield strength with considerable loss in the (-10 °C) CTOD fracture toughness (δfast cooling = 0.86 mm and δslow cooling = 1.12 mm) were demonstrated.

UR - http://www.scopus.com/inward/record.url?scp=76649115887&partnerID=8YFLogxK

U2 - 10.1007/s10853-009-4074-7

DO - 10.1007/s10853-009-4074-7

M3 - Article

AN - SCOPUS:76649115887

SN - 0022-2461

VL - 45

SP - 1248

EP - 1254

JO - Journal of Materials Science

JF - Journal of Materials Science

IS - 5

ER -

Effect of welding heat input on microstructure and mechanical properties of simulated HAZ in Cu containing microalloyed steel

Abstract

Funding

Access to Document

Other files and links

Fingerprint

Cite this