(10)Effect of Carbon, Manganese and Chromium Concentration, Density, Sintering Temperature and Post-Sintering Cooling Rate on Properties of Lean Alloy PM Steels

摘要

A comprehensive study has been carried out to evaluate the effect of C, Mn and Cr concentrations as well as density, sintering temperature and post-sintering cooling rate on properties of lean alloy PM steels produced with a 0.5% Mo low alloy steel and a carbon master alloy containing 2% C and 1% Si. A Taguchi L27 array was used to minimize the number of tests while getting enough data to develop predicting models. The dimensional change increased linearly with the green density and concentrations of C, Mn and Cr and decreased with the sintering temperature. Apparent hardness increased linearly with the concentration of C, Mn and Cr, sintered density and post-sintering cooling rate. However, tensile and yield strengths did not follow a linear model. For increased concentration of C, Mn and Cr, maxima were shifted toward lower carbon concentration as the levels of Mn, Cr and the post-sintering cooling rate increased. Finally, elongation increased linearly with sintered density but decreased linearly with the concentration of C, Mn and Cr and with the post sintering-cooling rate.