Heat Treatment Optimization of CA-6NM Cast Alloy Using a Full Factorial Design of Experiments Approach Article uri icon

abstract

  • A full factorial experimental design was used to study the effect of each parameter involved in the heat treatment of the CA-6NM cast alloy, in order to optimize this process for achieving specific hardness values after single or double tempering-processes. The statistical analysis of the experimental results with ANOVA showed that the chemical composition, the equivalent Cre/Nie ratio and the carbon content are critical parameters that should be considered for the determination of AC1 temperature. For a single tempering process, a decrement from 30HRC to 25HRC was reached as the austenitizing and tempering temperatures were increased or with prolonged austenitizing times. In order to achieve specific hardness values < 23HRC with a double tempering-process, it is necessary to increase the first tempering temperature, increase time in the first and second tempering and use a more severe cooling rate between both tempering stages. Procedures for hardness level optimization in this alloy with both tempering processes were proposed using contour plots, which were obtained from a mathematical model that had been statistically validated. © 2020, American Foundry Society.

publication date

  • 2021-01-01