摘要
采用DIL805A型相变仪,测定含硼P20B钢在850～1 000℃的奥氏体化条件下的过冷奥氏体在640～720℃等温时的C曲线;结合.850～1 000℃奥氏体化条件下晶粒度的测定和第二相分析,研究硼对P20B钢淬透性的影响行为.结果表明:在850～920℃的温度范围内,随着奥氏体化温度的升高,晶粒略有长大,固溶硼含量显著增加,使高温C曲线明显右移,即淬透性明显提高;而在920～1 000℃的温度范围内,随着奥氏体化温度的升高,晶粒显著长大,固溶硼含量不再明显增加,此时淬透性不再明显提高.
Abstract
The C curve of supercooled austenite of plastic mould steel P20B was investigated with the DIL805A dilatometric instrument.The austenitizing temperature was between 850 ℃ and 1 000 ℃ and the isothermal temperature between 640 ℃ and 720 ℃.We compared austenite grain size at different austenitizing temperatures and analyzed the second phase which obtained from the electrolytic extraction procedure.The results show that at 850 ～ 920 ℃ in the temperature range when the austenitizing temperature is increased, the grains grow slightly, the content of B increased significantly to make the C curve strongly shift right.At 920 ～ 1 000 ℃ in the temperature range when the austenitizing temperature is increased, the grains grow significantly, and the content of B no longer increases so hardenability of P20B steel does not increased.
基金项目
国家科技部"十一五"科技资助项目(2007BAE51D04)
NETL
NSTL
维普
万方数据