Mould hardness & Core hardness
References:
Sarkar, A. D. (2014). Mould & core material for the steel foundry. Elsevier
Groover, Mikell P., 1939-. (2007). Fundamentals of modern manufacturing: materials, processes, and systems. Hoboken, NJ: J. Wiley & Sons
P. L. Jain, “Principle of Foundry Technology,” 4th Edition, McGraw-Hill, New Delhi, 2006