钢中MnS对BN析出行为的影响

Effects of MnS on BN Precipitation in Steel

采用α粒子径迹法和电子显微镜研究了含微量硼的低碳钢中MnS对BN析出行为的影响。结果表明,当加热温度低于1150℃时,BN多以球状的MnS为结晶核心在其周围析出,呈MnS+BN复合体形态;当加热温度超过1150℃时,未固溶的MnS大部分由球形变成多面体形,这种形状的MnS已失去BN结晶核心的作用。除了呈MnS+BN复合体存在的BN外,也有单体的BN,随着温度的提高和保温时间的延长,其尺寸变大,形貌各异。

The α-particle autoradiograph and microscope were applied for studying the effects of MnS on BN precipitation in the steel containing small amount of boron.The results showed that BN nucleated on the spherical MnS and formed the compound of MnS＋BN.With the increase of heating temperature over 1150 ℃,most of undissolved MnS particles were transformed to the shape of polyhedron,and would be ineffective for BN nucleation anymore.In addition there were also monomers of BN with different shapes formed in steel during heat treatment and their dimensions were getting larger with increase of temperature and holding time.