Benchmarking Values of Modulus of Rupture for Shells Used in Different Investment Casting Segments

Modulus of Rupture (MoR) is considered to be one of the most crucial properties of ceramic shells used in manufacturing investment castings. An industrial survey was conducted to get an insight into the availability of such facilities to measure this property even after guidelines about measurement as well as its relevance are very well established. However, benchmarking values of MoR especially for various segments including aerospace, automobile as well as chemical where investment castings are widely employed are not clearly traceable in the literature. The proposed research is mainly focused on the development of MoR testing machine as per established specific guidelines followed by benchmarking values of MoR for specific sectors mentioned above as these sectors use as much as 60% of total investment casting produced in India. Tested samples were specifically prepared to replicate the conditions that are followed in making of shells and samples were tested using a developed MoR machine. It was observed that values of MoR need to be 4.15–4.90 MPa for automobiles; 3.14–4.48 MPa for chemicals and 1.54–2.76 MPa for aerospace to avoid any unwanted effects of MoR on the quality of investment castings used in these segments.