Tensile strength and hardness of sub-zero chilled cast iron

摘要

This paper describes the results obtained and the deductions made from a series of ultimate tensile strength (UTS) and hardness tests performed on sub-zero chilled (using liquid nitrogen) cast iron containing 1.5% Cu, and of chromium contents ranging from 0.0% to 0.2%. By using copper chills of different thicknesses, the effect on UTS and hardness of varying the chill rate was also examined. All the tests were carried out in conformance with AFS (American Foundryman's Society) standards. It was found that both the UTS and hardness are significantly increased when chromium content and/or rate of cooling are increased. Moreover, it was found that, like steel and grey cast iron, the hardness of sub-zero chilled cast iron has a definite linear relationship with the UTS. This means that it is possible to predict the hardness if the UTS is known and vice versa.