The formation mechanisms of interlocked microstructures in low-carbon high-strength steel weld metals

Wan, Xiangliang; Wang, H.H.; Cheng, Lin; Wu, Kaiming

doi:10.1016/j.matchar.2012.02.007

Cited by 81 publications

(38 citation statements)

References 25 publications

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“…However, this inclusion type was identified as inactive for acicular ferrite, contrasting with the literature reports. [12,13,42] Small amounts of pure MnS particles were found in steel C1. Most MnS particles were composed of a heterogeneously nucleated layer on oxidic inclusions.…”

Section: Steel B1mentioning

confidence: 99%

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On the Capability of Nonmetallic Inclusions to Act as Nuclei for Acicular Ferrite in Different Steel Grades

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Michelic

Mayerhofer

et al. 2017

Metall Mater Trans B

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Acicular ferrite nucleates intragranularly on nonmetallic inclusions, forming a microstructure with excellent fracture toughness. The formation of acicular ferrite is strongly affected by the size, content, and composition of nonmetallic inclusions, but also by the composition of the steel matrix. The potential of inclusions in medium carbon HSLA (high-strength low-alloyed) steels has been the main focus in the literature so far. The current study evaluates the acicular ferrite capability of various inclusions types in four different steel grades with carbon contents varying between 0.04 and 0.65 wt pct. The investigated steels are produced by melting experiments on a laboratory scale and subsequent heat treatment in a High-Temperature Laser Scanning Confocal Microscope. Inclusions are exclusively formed by deoxidation and desulfurization reactions. No synthetic particles are added to the melt. The inclusion landscape is analyzed by Scanning Electron Microscopy. Final ductility of the samples is evaluated based on performed tensile tests. Inclusion types in every steel grade are assessed regarding their nucleation potential always considering the interaction with the steel composition, especially focusing on the role of manganese. The effects of (Ti,Al)O x -, MnS-, and MgO-containing inclusions are discussed in detail.

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Section: Steel B1mentioning

confidence: 99%

“…This effect was first observed for weld metals. [8] Comprehensive reviews on the formation of acicular ferrite have been done by Bhadeshia [9] as well as Sarma et al [10] Up to now, C-Mn-(Ni) weld metals [11][12][13][14][15] were the most investigated material related to the formation of acicular ferrite.…”

Section: Introductionmentioning

confidence: 99%

On the Capability of Nonmetallic Inclusions to Act as Nuclei for Acicular Ferrite in Different Steel Grades

Loder

Michelic

Mayerhofer

et al. 2017

Metall Mater Trans B

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“…Terasaki e Komizo [5] chegam a essa conclusão observando a nucleação e desenvolvimento "in situ" da ferrita acicular usando LSCM (Laser Scan Confocal Microscope) e forno de imagem infravermelha. Wan et al [6] usam reconstrução de imagem em três dimensões para observar o mesmo fenômeno. Com base nessas características Strangwwod e Bhadeshia definiram a ferrita acicular como sendo bainita nucleada intragranularmente [4].…”

Section: Introductionunclassified

Influência do uso de PTFE como aglomerante em eletrodos revestidos básicos sobre a formação de ferrita acicular no metal de solda

Vaz

Bracarense

2014

Soldag. insp.

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Metais de solda produzidos por eletrodos revestidos básicos aglomerados com politetrafluoretileno (PTFE) têm apresentado baixíssimos teores de hidrogênio difusível e elevadas frações volumétricas de ferrita acicular. Esse estudo investigou o papel desempenhado pelo polímero na formação de tal constituinte. A microestrutura produzida por consumíveis contendo esse componente apresentou quantidades de ferrita acicular consideravelmente superiores à prevista na literatura para um metal de solda com os mesmos teores de carbono, silício e manganês. Tal diferença não pode ser atribuída a variações nos parâmetros de soldagem empregados. A análise dos elementos químicos residuais apontou o nitrogênio como sendo o principal responsável pelas discrepâncias observadas na microestrutura. O estudo das características operacionais de eletrodos classe E7018 tradicionais e aglomerados com polímero mostrou que a menor absorção de nitrogênio pelo metal de solda se deve a dois fatores principais. Medidas do teor de nitrogênio dissolvido das gotas coletadas durante a soldagem do eletrodo aglomerado com polímero demonstrou uma atmosfera protetora mais efetiva. O teor de carbono presente no metal de solda obtido pela soldagem do eletrodo com polímero apontou para uma atmosfera rica nesse elemento. Tal característica é coerente com a hipótese de uma melhor proteção gasosa. O tamanho médio das gotas coletadas, teor de nitrogênio dissolvido em função do tamanho e os oscilogramas de tensão indicaram alterações no modo de transferência metálica.

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“…A, B and C. The typical needle-shaped morphology of martensite can be identified in all three alloys. While the blocks in alloys A/B show mostly parallel arrangements, alloy C comprises a more chaotic arrangement of blocks with large areas with interlocked structures similar to acicular ferrite [26,33]. Additionally, the blocks seem to be refined in alloys B and C. The optical appearance of these microstructures was quantified by evaluating the effective grain size and the misorientation distribution from several EBSD scans.…”

Section: Toughness Improvement and Microstructure-alloys A B Cmentioning

confidence: 99%

Microstructure and mechanical properties of high-strength steel welding consumables with a minimum yield strength of 1100 MPa

et al. 2018

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Welded high-strength steel components have great potential for use in lightweight constructions or highly loaded structures. Welding of steels with a yield strength of more than 1100 MPa is particularly challenging because of the toughness requirements for the weld metal. Currently, a new generation of welding consumables with a minimum yield strength of 1100 MPa has been developed. Based on electron backscatter diffraction and atom probe tomography, a concept for toughening and strengthening of all-weld metal samples was deployed. Starting from a martensitic all-weld metal sample with an approximate yield strength of 1000 MPa, a reduction in manganese and silicon content resulted in a refined microstructure with a lower prior austenite grain size and effective grain size. Furthermore, a higher average grain boundary misorientation was measured, which influences the toughness positively. An addition of vanadium caused the formation of vanadium-rich clusters, which increased the strength of the all-weld metal significantly. With a combination of these two mechanisms, it was possible to produce an all-weld metal sample with the required yield strength of more than 1100 MPa and an acceptable toughness.

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The formation mechanisms of interlocked microstructures in low-carbon high-strength steel weld metals

Cited by 81 publications

References 25 publications

On the Capability of Nonmetallic Inclusions to Act as Nuclei for Acicular Ferrite in Different Steel Grades

On the Capability of Nonmetallic Inclusions to Act as Nuclei for Acicular Ferrite in Different Steel Grades

Influência do uso de PTFE como aglomerante em eletrodos revestidos básicos sobre a formação de ferrita acicular no metal de solda

Microstructure and mechanical properties of high-strength steel welding consumables with a minimum yield strength of 1100 MPa

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