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

The effect of the casting modulus on the distribution and features of graphite in hypo-eutectic ductile iron unalloyed and alloyed with nickel (0.88 wt %) was studied. The cooling rate of the casting plates of 25.4, 12.7 and 8.5 mm in thickness with a casting modulus of 6.87, 4.46 and 3.31 mm, respectively promotes several microstructural changes, such as cementite precipitation and a noticeable nodule count increment. The nickel addition suppressed the cementite formation and improved the nodule count and nodularity for the three casting modulus evaluated. The nickel addition increased the nodule count in 69, 67 and 128 % for the modulus of 3.31, 4.46 and 6.87 mm, respectively, regarding the unalloyed ductile iron. It was found that the biggest casting modulus produced the biggest nodules with the lowest nodule count for both ductile cast irons. Further to the improvements in the graphite features, the nickel addition allowed to keep almost constant the yield and tensile strength ratio for the different casting modulus.

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Characteristics of cracks in heat affected zone of ductile cast iron in powder welding process

Engineering Failure Analysis ◽

10.1016/j.engfailanal.2010.08.002 ◽

2011 ◽

Vol 18 (1) ◽

pp. 47-51 ◽

Cited By ~ 21

Author(s):

F. Malek Ghaini ◽

M. Ebrahimnia ◽

Sh. Gholizade

Keyword(s):

Cast Iron ◽

Heat Affected Zone ◽

Welding Process ◽

Ductile Cast Iron

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Effects of silicon content and cooling rate on mechanical properties of heavy section ductile cast iron

10.37099/mtu.dc.etds/25 ◽

2011 ◽

Author(s):

Meghan Haycock

Keyword(s):

Mechanical Properties ◽

Cast Iron ◽

Cooling Rate ◽

Silicon Content ◽

Ductile Cast Iron ◽

Heavy Section

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Some Aspects on the Formation of the Microstructure in Multipass Welds in Ferritic Ductile Cast Iron

MRS Proceedings ◽

10.1557/proc-34-457 ◽

1984 ◽

Vol 34 ◽

Cited By ~ 1

Author(s):

G. Hällén

Keyword(s):

Cast Iron ◽

Weld Metal ◽

Heat Affected Zone ◽

Arc Welding ◽

Ductile Cast Iron ◽

Multipass Welding ◽

Graphite Morphology

ABSTRACTThe microstructure obtained in the heat-affected zone (HAZ) and the carbide zone in the weld metal adjacent to HAZ has been studied in multipass welds in ferritic ductile cast iron. The effects of postweld anneal were also studied. The amount of martensite in the HAZ and the carbide zone can be reduced by the heating cycles of subsequent weld beads during multipass welding. The amount of martensite in the structure affects the graphite morphology after postweld annealing in both the HAZ and the carbide zone. It is also proposed that the graphite in the carbide zone, when arc-welding ductile cast iron with no or moderate preheat, is formed from cementite by grafitization.

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Determination of Eutectoid Transformation Temperatures in Ductile Cast Iron

Archives of Foundry Engineering ◽

10.1515/afe-2015-0078 ◽

2015 ◽

Vol 15 (4) ◽

pp. 51-54 ◽

Cited By ~ 1

Author(s):

A.W. Orłowicz ◽

A. Trytek ◽

M. Mróz ◽

M. Tupaj

Keyword(s):

Cast Iron ◽

Cooling Rate ◽

Ductile Cast Iron ◽

Eutectoid Transformation ◽

Heating Rates ◽

Cooling Rates ◽

Metallographic Examination ◽

Transformation Temperatures ◽

Rate Of Cooling

Abstract The paper proposes a methodology useful in verification of results of dilatometric tests aimed at determination of temperatures defining the start and the end of eutectoid transformation in the course of ductile cast iron cooling, based on quenching techniques and metallographic examination. For an industrial melt of ductile cast iron, the effect of the rate of cooling after austenitization at temperature 900°C carried out for 30 minutes on temperatures TAr1start and TAr1end was determined. The heating rates applied in the study were the same as the cooling rates and equaled 30, 60, 90, 150, and 300°C/h. It has been found that with increasing cooling rate, values of temperatures TAr1start and TAr1end decrease by several dozen degrees.

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