易切削钢中Ca-Al-O-Mn-S系氧硫化物变性的热力学计算

THERMODYNAMICAL CALCULATION ABOUT THE MODIFICATION OF Ca-Al-O-Mn-S OXYSULFIDE IN FREE-CUTTING STEEL

本文对易切削钢中Ca-Al-O-Mn-S系氧硫化物变性进行了热力学计算。计算结果表明,硫含量愈高,氧硫化物变性所要求的Ca愈高而Al愈小。易切削钢中常见的是CA_6-(Mn,Ca)S和CA_2-(Mn,Ca)S。由于其较高的硫含量,液态CmA_n-(Mn,Ca)S不可能形成。实验结果同热力学计算相当吻合。

Thermodynamical calculation about the modification of Ca-Al-O-S-Mn oxysulfide in free-cutting steel has been made. The calculated result shows that the higher the S content, the higher the Ca content and the lower the Al content needed for the modification of oxysulfide. The common oxysulfides in free-cutting steel are CAS -(Mn,Ca)S and CA2-(Mn,Ca)S. Because of the higher S content in free-cutting steel, no liquid oxysutfide CmAn-(Mn,Ca)S exists. The experimental result conforms well to the thermo-dynamical calculation.