Effect of Electrode Types on the Solidification Cracking Susceptibility of Austenitic Stainless Steel Weld Metal

Anaele, Justus Uchenna; Onyemaobi, Okechukwu Onyebuchi; Nwobodo, C. S.; Ugwuegbu, C. C.

doi:10.1155/2015/213258

Cited by 4 publications

(6 citation statements)

References 7 publications

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“…Such data are important for determining the optimal conditions of the PCGTAW process for improving the hot‐cracking susceptibility of austenitic stainless‐steel thin sheets, as well as for deep interpretation and good correlation of the cracking behavior to the microstructure and macrostructure of the bead. Further work should focus on electrode materials, application of the process to dissimilar weld materials, and use of different gas mixtures 31,32 …”

Section: Resultsmentioning

confidence: 99%

Hot‐cracking susceptibility of fully austenitic stainless steel using pulsed‐current gas tungsten arc‐welding process

Abu‐Aesh

Taha

El–Sabbagh

et al. 2020

Engineering Reports

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The pulsed‐current gas tungsten arc‐welding process (PCGTAW) has recently been recommended as an approach to eliminate the high susceptibility of austenitic stainless steel to hot cracking. Within a wide range of variables, in the present study, the effects of pulse frequency, time ratio, and pulse current on the cracking susceptibility of austenitic stainless‐steel thin sheets are investigated. A fan‐shaped cracking test specimen is adopted, and suitable final dimensions are obtained by conducting some preliminary experiments. A good correlation is found between the maximum crack length, which is taken as a cracking susceptibility index, and the pulse form variables. The results are found to be significantly improved when compared with those of the continuous‐current process, which indicates that the PCGTAW process has an effective role in reducing the hot‐cracking susceptibility. The optimal conditions of the pulse form variables based on the hot‐cracking susceptibility are determined. The optimal values of the time ratio are found to be less than 50%, together with a pulse frequency of less than 1 Hz. Some new microstructure measures, such as columnar structure ratio, grain orientation angle, puddle diversion angle, and overlapping ratio, which are originally defined in this work, in addition to grain size and puddle form factor (aspect ratio), are used to interpret the hot‐cracking behavior. All are found to have a direct impact on the hot‐cracking susceptibility. The results obtained from microstructure examinations showed that the cracks formed are either intergranular or transgranular cracks.

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Section: Resultsmentioning

confidence: 99%

Hot‐cracking susceptibility of fully austenitic stainless steel using pulsed‐current gas tungsten arc‐welding process

Abu‐Aesh

Taha

El–Sabbagh

et al. 2020

Engineering Reports

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“…The concern is also that duplex microstructure contains comparatively lesser volume portion of retained ferrite, designated as delta ferrite [7,8]. The reduction in ferrite level is time subservient phenomenon, as the determination is diffusion controlled and the primary solidification segregation extent in both austenite and ferrite is also an agent in the degree of resolution of ferrite.…”

Section: Figure 1: Vertical Section Of the Fe-cr-ni Phase Diagram At mentioning

confidence: 99%

Depiction of Detrimental Metallurgical Effects in Grade 304 Austenitic Stainless Steel Arc Welds

Saluja¹,

Tjprc²

2018

IJMPERD

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Efforts have been made to integrate fundamental microscopic behaviour and metallurgical transformations of Grade 304 Austenitic stainless steel during solidification. Incomplete mixing during solidification of Grade 304 steel in weld pool initiates segregation that encourages the dendritic envelope motion regulated by the enlargement of dendrite tips. High segregation of chromium and molybdenum, lead to the formation of secondary ferrite that increases tendency of accumulation of intermetallic phases. Micro and macro cracks with different orientations also occur in various sections of the weld, because of low melting liquid phases in the primary weld zone or enveloping HAZ. It aggravates grain boundaries to split under the thermal and shrinkage strain during metallurgical changes. Solid-state transformation of ferrite to austenite results in separation of solidification boundaries from grain boundaries thus reduces possibility of hot cracking. But probability of fissuring in the weld HAZ in fully austenite welds is higher than in ferrite containing welds. Contending variables adjoin complexity, hence the primary intention of this review is to correlate microstructural developments of Grade 304 steel under the influence of metallurgical variations.

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“…Autogenous fusion welding and welding with the matching fillers of the alloy 800H are reported to suffer from hot cracking, either in the fusion zone or in the terminal weld crater [ 6 ]. Alloys that solidify directly as austenitic show a higher propensity towards hot cracking due to the lower solubility of the non-metallic impurities in the primary austenitic grains [ 7 ]. The segregation of non-metallic impurities depresses the melting point of the grain boundary liquid phase.…”

Section: Introductionmentioning

confidence: 99%

Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

et al. 2021

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This study evaluated the microstructure, grain size, and mechanical properties of the alloy 800H rotary friction welds in as-welded and post-weld heat-treated conditions. The standards for the alloy 800H not only specify the composition and mechanical properties but also the minimum grain sizes. This is because these alloys are mostly used in creep resisting applications. The dynamic recrystallization of the highly strained and plasticized material during friction welding resulted in the fine grain structure (20 ± 2 µm) in the weld zone. However, a small increase in grain size was observed in the heat-affected zone of the weldment with a slight decrease in hardness compared to the base metal. Post-weld solution heat treatment (PWHT) of the friction weld joints increased the grain size (42 ± 4 µm) in the weld zone. Both as-welded and post-weld solution heat-treated friction weld joints failed in the heat-affected zone during the room temperature tensile testing and showed a lower yield strength and ultimate tensile strength than the base metal. A fracture analysis of the failed tensile samples revealed ductile fracture features. However, in high-temperature tensile testing, post-weld solution heat-treated joints exhibited superior elongation and strength compared to the as-welded joints due to the increase in the grain size of the weld metal. It was demonstrated in this study that the minimum grain size requirement of the alloy 800H friction weld joints could be successfully met by PWHT with improved strength and elongation, especially at high temperatures.

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Effect of Electrode Types on the Solidification Cracking Susceptibility of Austenitic Stainless Steel Weld Metal

Cited by 4 publications

References 7 publications

Hot‐cracking susceptibility of fully austenitic stainless steel using pulsed‐current gas tungsten arc‐welding process

Hot‐cracking susceptibility of fully austenitic stainless steel using pulsed‐current gas tungsten arc‐welding process

Depiction of Detrimental Metallurgical Effects in Grade 304 Austenitic Stainless Steel Arc Welds

Influence of Post Weld Heat Treatment on the Grain Size, and Mechanical Properties of the Alloy-800H Rotary Friction Weld Joints

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