The Effect of Shell Thickness, Insulation and Casting Temperature on Defects Formation During Investment Casting of Ni-base Turbine Blades

• Autorzy: Raza M. , Irwin M. , Fagerström B.

Identyfikatory

DOI

10.1515/afe-2015-0090

• Języki publikacji: EN

Abstrakty

EN

Turbine blades have complex geometries with free form surface. Blades have different thickness at the trailing and leading edges as well as sharp bends at the chord-tip shroud junction and sharp fins at the tip shroud. In investment casting of blades, shrinkage at the tip-shroud and cord junction is a common casting problem. Because of high temperature applications, grain structure is also critical in these castings in order to avoid creep. The aim of this work is to evaluate the effect of different process parameters, such as, shell thickness, insulation and casting temperature on shrinkage porosity and grain size. The test geometry used in this study was a thin-walled air-foil structure which is representative of a typical hot-gas-path rotating turbine component. It was observed that, in thin sections, increased shell thickness helps to increase the feeding distance and thus avoid interdendritic shrinkage. It was also observed that grain size is not significantly affected by shell thickness in thin sections. Slower cooling rate due to the added insulation and steeper thermal gradient at metal mold interface induced by the thicker shell not only helps to avoid shrinkage porosity but also increases fill-ability in thinner sections.

Słowa kluczowe

EN

investment casting; casting defect; shrinkage porosity; grain structure; turbine blade; Niyama criterion

PL

odlewanie precyzyjne; wada odlewu; struktura ziarnista; łopatka turbinowa; kryterium Niyamy

• Wydawca: Komisja Odlewnictwa Polskiej Akademii Nauk Oddział w Katowicach
• Czasopismo: Archives of Foundry Engineering
• Rocznik: 2015
• Tom: Vol. 15, iss. 4
• Strony: 115--123
• Opis fizyczny: Bibliogr. 11 poz., rys., tab., wykr.

Twórcy

autor

Raza M.

• School of Innovation, Design and Engineering, Mälardalen University, Smedjegatan 37, 632 20 Eskilstuna, Sweden; TPC Componenst AB, Brånstaleden 2, 734 92 Hallstahammar, Sweden

autor

Irwin M.

• TPC Componenst AB, Brånstaleden 2, 734 92 Hallstahammar, Sweden

autor

Fagerström B.

• School of Innovation, Design and Engineering, Mälardalen University, Smedjegatan 37, 632 20 Eskilstuna, Sweden

Bibliografia

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