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Repair of Precision Castings Made of the Inconel 713C Alloy

Łyczkowska K., Adamiec J.

Archives of Foundry Engineering

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2017

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Vol. 17, iss. 3

210--216

EN

Inconel 713C precision castings are used as aircraft engine components exposed to high temperatures and the aggressive exhaust gas environment. Industrial experience has shown that precision-cast components of such complexity contain casting defects like microshrinkage, porosity, and cracks. This necessitates the development of repair technologies for castings of this type. This paper presents the results of metallographic examinations of melted areas and clad welds on the Inconel 713C nickel-based superalloy, made by TIG, plasma arc, and laser. The cladding process was carried out on model test plates in order to determine the technological and material-related problems connected with the weldability of Inconel 713C. The studies included analyses of the macro- and microstructure of the clad welds, the base materials, and the heat-affected zones. The results of the structural analyses of the clad welds indicate that Inconel 713C should be classified as a low-weldability material. In the clad welds made by laser, cracks were identified mainly in the heat-affected zone and at the melted zone interface, crystals were formed on partially-melted grains. Cracks of this type were not identified in the clad welds made using the plasma-arc method. It has been concluded that due to the possibility of manual cladding and the absence of welding imperfections, the technology having the greatest potential for application is plasma-arc cladding.

2

Shape Accuracy of Iron Precision Castings in Terms of Ceramic Moulds Physical Properties Anisotropy

Biernacki R., Haratym R., Tomasik J., Kwapisz J.

Archives of Foundry Engineering

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2014

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Vol. 14, iss. 1

5--8

EN

While analyzing shape accuracy of ferroalloy precision castings in terms of ceramic moulds physical anisotropy, low-alloy steel castings ("cover") and cast iron ("plate") were included. The basic parameters in addition to the product linear shape accuracy are flatness deviations, especially due to the expanded flat surface which is cast plate. For mentioned castings surface micro-geometry analysis was also carried, favoring surface load capacity tp50 for Rmax = 50%. Surface load capacity tp50 obtained for the cast cover was compared with machined product, and casting plate surface was compared with wear part of the conveyor belt. The results were referred to anisotropy of ceramic moulds physical properties, which was evaluated by studying ceramic moulds samples in computer tomography equipment Metrotom 800.

3

The influence of organic fibre types on technological parameters in process of ceramic moulds making

Karwiński A., Młodnicki S., Meksa W., Woźnicki G.

Archives of Foundry Engineering

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2007

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Vol. 7, iss. 2

143-146

EN

The research being presented in this article has been set up with the aim of working out both the technology and starting up manufacturing process ( in which a new generation of ceramic slips is employed ) in "Armatura" precise foundry. There have been used "aqueous" Ekosil silicate binder and quartz ceramic material with addition of organic fibres for making slip in the new technological solution. In the presented research work has been achieved a quantitative and qualitative selection of composition for the ceramic slip. The selection has been based on testing of physico-chemical and technological qualities.

4

Mikrostruktura od powierzchni odlewów precyzyjnych z ADI po bezpośrednim hartowaniu izotermicznym

Myszka D., Kaczorowski M.

Archiwum Odlewnictwa

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2004

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R. 4, nr 11/1

350--354

PL

Szczegółowe badania metalograficzne żeliwa sferoidalnego, które poddane było hartowaniu izotermicznemu bezpośrednio z formy odlewniczej (DADI), wykazały bardzo podobną mikrostrukturę rdzenia odlewu do mikrostruktury ADI otrzymanego w wyniku klasycznej obróbki cieplnej. Stwierdzono jednak, iż od powierzchni odlewu mikrostruktura ta różni się dla obu procesów. Dla DADI była to rozdrobniona, klasyczna mieszanina płytek ferrytu i austenitu (ausferryt). Dla odlewów z żeliwa sferoidalnego austenityzowanych i hartowanych izotermicznie widoczne jest natomiast powierzchniowe odwęglenie, a tym samym nieco inna morfologia warstwy wierzchniej. Stwierdzono również, że obecność mikrostruktury ausferrytycznej od powierzchni odlewu precyzyjnego wykonanego z DADI jest bardzo korzystna z punktu widzenia jego własności użytkowych. Ausferryt zapewnia bowiem odpowiednią twardość, ale również wysoką odporność na ścieranie i kruche pękanie, co ma niebagatelne znaczenie dla wyrobów wykonanych ,,na gotowo".

EN

The detailed microstructural investigation of direct austempesed ductile iron (DADI) showed very similar matrix morphology to ausferrite observed in conventional ADI. It was noticed that the surface microstructure of ADI and DADI was different. Surface of ADI was decarburized and DADI had the same as a core microstructure from the surface of investment casting. Such morphology of DADI has positive effect on its surface mechanical properties.