Effect of fine alumina in improving refractoriness of ceramic shell moulds used for aeronautical grade Ni-base superalloy castings

Venkat, Y.; Singh, Sarabjit; Das, Dipak K.; Pandey, Akash

doi:10.1016/j.ceramint.2018.03.197

Cited by 15 publications

(2 citation statements)

References 8 publications

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“…Alumina is one of the most widely used refractories in the directional solidification of superalloy blades [ 26 , 27 ]. It has stable high-temperature mechanical properties, a low thermal expansion coefficient and a relatively high chemical inertia to most alloy melts.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Fused Alumina Based-Mold Facecoats for DZ22B Directionally Solidified Blades

Yang

et al. 2019

Materials

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The interaction between alloy melt and mold facecoats is the main factor affecting the surface quality of investment casting nickel-based superalloys. An investigation was undertaken to develop suitable refractories as facecoat materials for the directionally solidified blades of DZ22B nickel-based superalloys in order to avoid a sand-burning defect. The wettability and interface reactions between alloy melt and various facecoats were studied by using a sessile drop experiment and the real investment casting method, respectively. The results show that by adding Cr2O3 powder with the amounts of 2 wt.%, 5 wt.% and 10 wt.% in the fused alumina-based facecoats, the wetting angles between the alloy melt and facecoats decreased from 105.40° to 100.37°, 99.96° and 98.11°, respectively, while the sand-burning defect on the casting blade surfaces still formed during the process of directional solidification. However, by adding h-BN powder in the fused alumina-based facecoats, the wetting angles between the alloy melt and facecoats dramatically increased, the sand-burning defect on the casting blade surfaces was effectively inhibited and a metallic luster on the directionally solidified blades could be obviously observed. In this study, the suitable composition of mold facecoats for the investment casting of blades is 2 wt.% h-BN added fused alumina.

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Section: Introductionmentioning

confidence: 99%

Investigation of Fused Alumina Based-Mold Facecoats for DZ22B Directionally Solidified Blades

Yang

et al. 2019

Materials

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“…For this analysis, hypoeutectic Al-Si 7%-Mg alloy for casting in ceramic shells has been used. On the basis of literature survey [17][18][19][20][21][22], significant process parameters chosen for the study are shell preheat temperature, firing temperature, firing time and pouring temperature to identify their effect on casting shrinkage (both linear and volumetric) and tensile strength of the part produced via IC, while other parameters such as shell thickness, shell drying time, pouring time and cooling condition were kept nearly constant. The range of all the selected input process parameters were decided from the state of the art survey on aluminium alloy castings [23][24][25][26] and trial experiments conducted prior to the final experimentation.…”

Section: Introductionmentioning

confidence: 99%

Investigation on controlling the process parameters for improving the quality of investment cast parts

Pattnaik

2018

J Braz. Soc. Mech. Sci. Eng.

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Investment casting is a highly flexible process which was previously perceived as an expensive process. However, when the process is compared to other optional processes which may require machining or welding, this casting can produce metallic components at highly competitive costs. There are many process variables which affect the process such as die temperature, wax temperature, injection pressure, shell firing temperature and time, cooling rate. In this study, important shell parameters such as preheat temperature, firing temperature and firing time, and melt pouring temperature have been chosen as process variables influencing the quality of the hypoeutectic aluminium-silicon alloy investment casting. The optimal input parametric condition for reduction of linear and volumetric shrinkages and increment of tensile strength of Al-Si 7%-Mg investment casting has been identified as shell preheat temperature of 200°C, firing temperature of 900°C, firing time of 7 h and pouring temperature of 600°C. At this optimal setting, it was found that linear and volumetric shrinkages decreased from 0.65 and 1.89% to 0.381 and 1.546%. The tensile strength of the casting increased from 96 to 121 MPa with regard to the nine experimental runs performed. Microstructural observation revealed that higher shell preheat and pouring temperatures led to augmented porosity, increased secondary dendrite arm spacing (35.53 ± 2.4 lm), larger detrimental iron-rich intermetallics (40.49 ± 25.15 lm) followed by reduced tensile properties of the casting (96 MPa).

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Modification of ceramic shell facecoat for inhibition of sand burning defect on DZ22B directionally solidified blades

Chen

Zhao

et al. 2018

Int J Adv Manuf Technol

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Effect of fine alumina in improving refractoriness of ceramic shell moulds used for aeronautical grade Ni-base superalloy castings

Cited by 15 publications

References 8 publications

Investigation of Fused Alumina Based-Mold Facecoats for DZ22B Directionally Solidified Blades

Investigation of Fused Alumina Based-Mold Facecoats for DZ22B Directionally Solidified Blades

Investigation on controlling the process parameters for improving the quality of investment cast parts

Modification of ceramic shell facecoat for inhibition of sand burning defect on DZ22B directionally solidified blades

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