Correlation between microstructure and creep performance of martensitic/austenitic transition weldment in dependence of its post-weld heat treatment

Falat, Ladislav; Čiripová, Lucia; Kepič, Ján; Buršı́k, Jiřı́; Podstranská, Ivana

doi:10.1016/j.engfailanal.2014.02.018

Cited by 35 publications

(21 citation statements)

References 35 publications

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“…The final constant tendency of hardness profile values to be around 640-650 HV is related to the original QT microstructure of AISI H11 base material unaffected by the used LSH treatment. It can be stated that the observed hardness profile gradient reflects the typical general shape of hardness profiles observed in fusion weldments of ferritic steels involving the welds of ferritic structural steels and those of normalized and tempered martensitic steels for high temperature applications [17]. Moreover, Kasman and Saklakoglu [18] also observed similar hardness gradient of laser engraved AISI H13 tool steel investigated in their study on the effect of process parameters on the steel surface characteristics.…”

Section: Microhardness Measurementssupporting

confidence: 65%

The Effects of Laser Surface Hardening on Microstructural Characteristics and Wear Resistance of AISI H11 Hot Work Tool Steel

Šebek¹,

Falat²,

Kováč³

et al. 2017

Archives of Metallurgy and Materials

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The present study deals with the effects of laser surface treatment on microstructure evolution and wear resistance of AISI H11 hot work tool steel in quenched and tempered condition. The most upper laser-affected zone is characterized by re-melted microstructure consisting of dendrite cells with fresh non-tempered martensite, retained austenite and inter-dendritic carbidic network. The subsolidus microstructure just beneath the re-melted zone represents the most laser surface hardened zone consisting of fresh non-tempered martensite with fine and coarse carbides as a result of overheating the original QT substrate microstructure. The highest microhardness values in the range from 775 to 857 HV were measured for the LSH microstructure and the most softened microstructure exhibited the minimum hardness of 530 HV. The laser treated samples showed the improvement of their surface wear resistance by 35%.

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Section: Microhardness Measurementssupporting

confidence: 65%

The Effects of Laser Surface Hardening on Microstructural Characteristics and Wear Resistance of AISI H11 Hot Work Tool Steel

Šebek¹,

Falat²,

Kováč³

et al. 2017

Archives of Metallurgy and Materials

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“…2b and 4). Detailed microstructural analysis of Nirod 600 weld metal was performed in our previous studies on T92/TP316H weldments [39,40].…”

Section: Microstructure In Pwht Statementioning

confidence: 99%

“…Moreover, it has been shown in many studies, e.g. [40,42,43] that hardness peaks in the welds over-heated regions remain still present even after long-term thermal or creep expositions. Therefore, in the present investigation, all experimental work was focused on these critical HAZ regions.…”

Section: Mechanical Properties and Microstructure Evolutionmentioning

confidence: 99%

“…8). The coarsening rate of Laves phase is faster than that of M 23 C 6 carbides, and the finest MX particles seem to be thermally stable as their size and distribution do not un- dergo any significant changes during the long-term ageing process [23,24,40,41]. Figure 12 shows fracture surfaces of T24 HAZ and T92 HAZ regions of thermally exposed (600 • C/5000 h) and hydrogen charged weldments after room-temperature notch tensile tests.…”

Section: Fracture Behaviourmentioning

confidence: 99%

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Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Falat¹,

Čiripová²,

Homolová³

et al. 2016

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The effects of thermal exposure at 600• C and subsequent electrolytic hydrogen charging at ambient temperature were studied in terms of their influence on notch-tensile properties and fracture behaviour of individual heat-affected zones (HAZ) of Ni-based transition weldments between T24 and T92 creep-resistant steels. The experimental welded joints were prepared by gas tungsten arc welding using "Inconel-type" filler metal Nirod 600. Post-weld heat treatment (PWHT) was carried out at 720• C for 2 h, followed by passive cooling within tempering furnace. Subsequent long-term ageing of two series of prepared T24/T92 dissimilar welds at 600• C for 1000 and 5000 h, respectively, led to gradual changes in both T24 and T92 HAZ microstructures, which were mainly related to their additional tempering accompanied by the coarsening of original precipitates as well as newly-formed secondary phases. The observed thermally-induced microstructural changes together with subsequently applied hydrogen charging effects resulted in complex variations in tensile properties and fracture behaviour of individual HAZ regions related to the pre-existing differences in their initial tempering grade due to the used PWHT procedure. K e y w o r d s : creep-resistant steels, dissimilar welding, isothermal ageing, hydrogen embrittlement, mechanical properties, fracture mechanisms

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“…Chunky graphite is formed inside the cells, while the cell boundaries may also contain the well formed spheres -it is a case of the thicker walls of the cast. Metallurgical flaws may exist not only in the casts but also in the welded joints [1][2][3].…”

Section: Introductionmentioning

confidence: 99%

Elimination of Chunky Graphite in Castings with Large Thermal Points

Futáš¹

2016

Archives of Foundry Engineering

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The presence of the chunky graphite is unwanted in the cast iron with the spheroidal graphite for this significantly lowers the properties of the ductile iron. This shape of the graphite is formed as the result of the slow cooling rate of the castings with large thermal point and also due to the presence of the elements which suppress the formation of the spheroidal graphite and support formation of the chunky graphite. The spheroidal graphite present in the ductile iron assures the excellent mechanical properties, while the chunky graphite significantly reduces those properties of the ductile iron. Therefore it is of importance to assume conditions under which prevented is the formation of the chunky graphite. The casts were carried out under the conditions of the regular operation of the foundry and tested were various types of modifiers and inoculators and also pre-inoculators containing the elements suppressing the formation of the chunky graphite (Al, Sb a Ba). Applied were also the chromium breaker core to suppress the formation chunky graphite which was present in the structure in the places after the feeders elimination. As whole, executed were eight casts with various types of the modifiers and inoculators.

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Correlation between microstructure and creep performance of martensitic/austenitic transition weldment in dependence of its post-weld heat treatment

Cited by 35 publications

References 35 publications

The Effects of Laser Surface Hardening on Microstructural Characteristics and Wear Resistance of AISI H11 Hot Work Tool Steel

The Effects of Laser Surface Hardening on Microstructural Characteristics and Wear Resistance of AISI H11 Hot Work Tool Steel

Hydrogen pre-charging effects on the notch tensile properties and fracture behaviour of heat-affected zones of thermally aged welds between T24 and T92 creep-resistant steels

Elimination of Chunky Graphite in Castings with Large Thermal Points

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