Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation

The morphology of the grain structure in fusion welds is generally columnar and elongated. This structure is highly anisotropic and makes weld metal susceptible to centerline hot cracking and poor notch impact toughness particularly in welds that are prone to brittle fracture such as the ferritic s...

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Main Authors:	Amuda , Muhammed Olawale Hakeem, Mridha , Shahjahan
Format:	Article
Language:	English
Published:	David Publishing 2011
Subjects:	TN600 Metallurgy
Online Access:	http://irep.iium.edu.my/5468/ http://irep.iium.edu.my/5468/ http://irep.iium.edu.my/5468/1/JMSE-E20101227-5_editedproof.pdf

id	iium-5468
recordtype	eprints
spelling	iium-54682012-01-16T06:33:25Z http://irep.iium.edu.my/5468/ Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation Amuda , Muhammed Olawale Hakeem Mridha , Shahjahan TN600 Metallurgy The morphology of the grain structure in fusion welds is generally columnar and elongated. This structure is highly anisotropic and makes weld metal susceptible to centerline hot cracking and poor notch impact toughness particularly in welds that are prone to brittle fracture such as the ferritic stainless steel welds. An equiaxed grain structure is preferred in weld metal. Considerable studies have been undertaken to produce equiaxed grains in welds using different welding techniques. These studies established that grain refinement in welds has a linear relationship to the density of equiaxed grain in the columnar-equiaxed transition morphology at both the top surface and cross section of the weld. The increased density of equiaxed grains is due to the control of local solidification parameters both at the advancing solid/liquid interface and at the centre of the weld pool. Several mechanisms ranging from heterogeneous nucleation to dendrite fragmentation and grain detachment have been put forward to explain the phenomenon of grain refinement in fusion welds. These mechanisms are quite contrasting. In the present effort, a cross evaluation of these mechanisms is undertaken to identify the dominant mechanism. The evaluation suggested that other than in certain cases of compositional/ constitutional undercooling, dendrite fragmentation and grain detachment appear to be the controlling mechanisms except when specific steps are taken to introduce nuclei to promote heterogeneous nucleation. David Publishing 2011-08-10 Article PeerReviewed application/pdf en http://irep.iium.edu.my/5468/1/JMSE-E20101227-5_editedproof.pdf Amuda , Muhammed Olawale Hakeem and Mridha , Shahjahan (2011) Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation. Journal of Materials Science and Engineering A, 1. pp. 321-327. ISSN 1934-8959 http://www.davidpublishing.com/search.asp
repository_type	Digital Repository
institution_category	Local University
institution	International Islamic University Malaysia
building	IIUM Repository
collection	Online Access
language	English
topic	TN600 Metallurgy
spellingShingle	TN600 Metallurgy Amuda , Muhammed Olawale Hakeem Mridha , Shahjahan Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation
description	The morphology of the grain structure in fusion welds is generally columnar and elongated. This structure is highly anisotropic and makes weld metal susceptible to centerline hot cracking and poor notch impact toughness particularly in welds that are prone to brittle fracture such as the ferritic stainless steel welds. An equiaxed grain structure is preferred in weld metal. Considerable studies have been undertaken to produce equiaxed grains in welds using different welding techniques. These studies established that grain refinement in welds has a linear relationship to the density of equiaxed grain in the columnar-equiaxed transition morphology at both the top surface and cross section of the weld. The increased density of equiaxed grains is due to the control of local solidification parameters both at the advancing solid/liquid interface and at the centre of the weld pool. Several mechanisms ranging from heterogeneous nucleation to dendrite fragmentation and grain detachment have been put forward to explain the phenomenon of grain refinement in fusion welds. These mechanisms are quite contrasting. In the present effort, a cross evaluation of these mechanisms is undertaken to identify the dominant mechanism. The evaluation suggested that other than in certain cases of compositional/ constitutional undercooling, dendrite fragmentation and grain detachment appear to be the controlling mechanisms except when specific steps are taken to introduce nuclei to promote heterogeneous nucleation.
format	Article
author	Amuda , Muhammed Olawale Hakeem Mridha , Shahjahan
author_facet	Amuda , Muhammed Olawale Hakeem Mridha , Shahjahan
author_sort	Amuda , Muhammed Olawale Hakeem
title	Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation
title_short	Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation
title_full	Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation
title_fullStr	Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation
title_full_unstemmed	Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation
title_sort	mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation
publisher	David Publishing
publishDate	2011
url	http://irep.iium.edu.my/5468/ http://irep.iium.edu.my/5468/ http://irep.iium.edu.my/5468/1/JMSE-E20101227-5_editedproof.pdf
first_indexed	2023-09-18T20:14:05Z
last_indexed	2023-09-18T20:14:05Z
_version_	1777407670613966848

Mechanism of grain refinement in ferritic stainless steel welds: between dendrite fragmentation, grain detachment and heterogeneous nucleation

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