16I3EFFECT OF PROCESS PARAMETERS ON MEC

International Journal of Advances in Engineering & Technology, July 2011.
©IJAET
ISSN: 2231-1963

EFFECT OF PROCESS PARAMETERS ON
MECHANICAL PROPERTIES OF THE INVESTMENT
CASTINGS PRODUCED BY USING EXPANDABLE
POLYSTYRENE PATTERN
Nikhil Yadav1 and D. B. Karunakar2
1

2

M.Tech Scholar, Mechanical & Industrial Engg. Deptt., IIT Roorkee, Roorkee, India
Assistant Professor, Mechanical & Industrial Engg. Deptt., IIT Roorkee, Roorkee, India

ABSTRACT
The present study is concerned with the investigation of mechanical properties of A713 alloy castings produced by investment casting process using expandable polystyrene as the pattern material and the plaster of paris as the mould material. Experiments were conducted as per Taguchi’s L9 orthogonal array. Castings were made under the constraint of different process parameters like mould firing temperature, pouring temperature, firing time and mixing of silica sand of different grain fineness numbers to investigate their effects on the surface hardness, impact strength and tensile strength of the final castings. The variations in the trend of the aforesaid mechanical properties were observed and it was deduced out that high mould firing temperature, higher pouring temperature, maximum firing time and high grain fineness number significantly reduce the mechanical properties of A713 alloy castings produced by the above process.

KEYWORDS
Investment casting, Expandable polystyrene pattern, Plaster of Paris.

1. INTRODUCTION
Investment casting is known for its quality castings rendering good surface finish and other desirable mechanical properties. The investment casting process involves the production of engineering castings using an expandable pattern [8]. The principle can be traced back to 5000 BC [9]. Investment casting is also known for producing the intricate details and high dimensional accuracy. Castings are replicated from the precise pattern and transmitted in turn to the castings. Investment casting allows

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