Effect of cooling rate and powder characteristics on the soundness of heat affected zone in powder welding of ductile cast iron

Ebrahimnia, Mohamad; Ghaini, F. Malek; Gholizade, Sh.; Salari, Mahdi

doi:10.1016/j.matdes.2011.04.063

Cited by 31 publications

(19 citation statements)

References 8 publications

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“…The micro-cracks were often observed along matrix grain boundaries. Similar trend was reported in yet another paper [44]. Figure 13a shows the observed cracks.…”

Section: Microstructure Observationsupporting

confidence: 90%

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The microstructures, mechanical properties, and temperature distributions in nodular cast iron friction-welded joint

Winiczenko

Kaczorowski

Skibicki

2018

J Braz. Soc. Mech. Sci. Eng.

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The paper focuses on an experimental topic relating to the field of friction welding process of a nodular cast iron. The microstructures, phase transformation, temperature distributions, microhardness, and tensile test are all studied within the framework of the paper in question. Maximum temperature measurements in the axial center and periphery of the analyzed joints were equal to 950 and 840°C, respectively. Both temperature and increasing temperature gradient at the axial center were higher than those at the periphery. The maximum tensile strength of the examined friction-welded nodular cast iron joints was 53% of that of the parent metal. The welding region was composed of deformed graphite nodules, coarse pearlite, proeutectoid ferrite, and acicular martensite. Highly deformed graphite nodules were distributed along the weld interface due to the material flow in the thermo-mechanically affected zone (TMAZ). In the central zone, graphite displayed a striped configuration and ferrite transformed into a martensite structure. In the peripheral region, graphite surrounded by martensite kept the form of individual granules. Maximum hardness at the interface in the TMAZ and the heat-affected zone reached 603 HV and 345 HV, respectively. The executed microstructure analysis showed that the cracks started occurring mostly at the interface of the deformed graphite nodules and then spread through the grain boundaries of metal matrix. The fracture surface appearance showed a cleavage fracture in the peripheral zone and a little dimple fracture around graphite nodules in the central zone.

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“…The micro-cracks were often observed along matrix grain boundaries. Similar trend was reported in yet another paper [44]. Figure 13a shows the observed cracks.…”

Section: Microstructure Observationsupporting

confidence: 90%

“…13a). However, when thermal stress was further developed in the adjacent areas, another crack initiated from the graphite particle and propagated in the metal matrix [44]. The connection of these minor cracks led to the formation of large major cracks, which run through martensite structures.…”

Section: Microstructure Observationmentioning

confidence: 99%

The microstructures, mechanical properties, and temperature distributions in nodular cast iron friction-welded joint

Winiczenko

Kaczorowski

Skibicki

2018

J Braz. Soc. Mech. Sci. Eng.

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“…Usually, the selected pre-heating temperature depends on the chemical composition or carbon equivalent (CE) of the iron, which conditions the hardenability of the DCI [20]. Ebrahimnia et al [26] achieved good results in terms of avoiding crack formation by performing a local pre-heat treatment with a temperature of 300 • C before welding large forming dies (found in presses for the production of vehicle body panels), as well as a PWHT 400-500 • C with different cooling rates when powder welding DCIs. On the other hand, El-Banna [20] tested four preheating temperatures (25 • C, 200 • C, 300 • C and 400 • C), concluding that the best range of temperatures for these types of irons is between 200 • C and 300 • C. Moreover, Bęczkowski [28] refers that the control of interpass temperatures (up to 300 • C) and pre-heating temperatures (up to 200 • C) promotes the quality of the welds when repairing massive castings.…”

Section: Introductionmentioning

confidence: 99%

Study of the Heat-Treatments Effect on High Strength Ductile Cast Iron Welded Joints

Gouveia

Silva

Paiva

et al. 2017

Metals

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Nowadays, ultimate tensile strengths above 400 MPa become usual for ductile irons, thus allowing the implementation of new design paradigms. Large concentrations of carbon and other influencing elements can negatively interfere with the welding process of ductile cast irons. Efforts made by researchers have led to the discovery of solutions which enable good enough operational results to consider welding as a viable repairing or joining method. Although these alloys have been available for quite some time, researchers have mainly focused on issues relating to microstructural phenomena tied to casting and similar processes, leaving much to explore in terms of their weldability. Thus, this work intends to investigate the effect of different heat-treatments on the weldability of a high strength ductile cast iron by assessing the mechanical properties of welded joints as well as structural modifications induced by thermal cycles imposed before and after welding. Successful weld joints were achieved showing a clear heat affected zone (HAZ) close to the joint area. This area is coincident with the fracture area of the welded samples when loaded on a tensile test bench, having obtained promising results regarding mechanical strength and strain. The hardness of the welded zone was also carefully investigated, showing clear changes throughout the joint.

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“…However, there was no evidence, either from their XRD or microstructural analysis, of any phases other than ferrite, austenite and Fe 3 C. In a study by Yi et al [9], based on repair technology using the rapid solidification process by laser fusion welding, they discovered that overall crack toughness of the material can be increased around the repaired zone (RZ). This was further explained by Ebrahimnia et al [10] who stated that cracks initiate mostly at the interface of graphite and then propagate through the matrix of a component thereby causing fracture.…”

Section: Introductionmentioning

confidence: 89%

Effect of rapid solidification on the microstructure and microhardness of BS1452 grade 250 hypoeutectic grey cast iron

Oloyede

Mullis

2017

Journal of Alloys and Compounds

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ReuseUnless indicated otherwise, fulltext items are protected by copyright with all rights reserved. The copyright exception in section 29 of the Copyright, Designs and Patents Act 1988 allows the making of a single copy solely for the purpose of non-commercial research or private study within the limits of fair dealing. The publisher or other rights-holder may allow further reproduction and re-use of this version -refer to the White Rose Research Online record for this item. Where records identify the publisher as the copyright holder, users can verify any specific terms of use on the publisher's website. TakedownIf you consider content in White Rose Research Online to be in breach of UK law, please notify us by emailing eprints@whiterose.ac.uk including the URL of the record and the reason for the withdrawal request. respectively). Microstructural analysis reveals that the as-received bulk sample displayed a graphitic structure while the rapidly cooled samples display decreasing amounts of -Fe as the cooling rate increases. At moderate cooling rates is replaced with and Fe 3 C, while at higher cooling rates with . Microhardness increase with cooling rate but cannot be mapped uniquely onto cooling rate, suggesting undercooling also influences the mechanical properties. Effect of rapid solidification on

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Effect of cooling rate and powder characteristics on the soundness of heat affected zone in powder welding of ductile cast iron

Cited by 31 publications

References 8 publications

The microstructures, mechanical properties, and temperature distributions in nodular cast iron friction-welded joint

The microstructures, mechanical properties, and temperature distributions in nodular cast iron friction-welded joint

Study of the Heat-Treatments Effect on High Strength Ductile Cast Iron Welded Joints

Effect of rapid solidification on the microstructure and microhardness of BS1452 grade 250 hypoeutectic grey cast iron

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