GCr15SiMn轴承钢铸锭的原位统计分布分析

对真空感应炉熔炼后浇注的GCr15SiMn轴承钢铸锭进行原位统计分布分析,研究过热度对铸锭C、Si、Mn、Cr元素偏析以及疏松的影响。研究表明:过热度较低时(25 ℃),受溶质元素在凝固前端大量形核以及钢液热对流差等影响,铸锭的凝固末端出现明显的偏析和缩孔,C元素的统计偏析度达7.83%,统计疏松度为1.76%;随着过热度的进一步提高(55 ℃),钢液的热对流有所加强,各元素的偏析情况得到一定的改善,C元素的统计偏析度和疏松度均达到最低,分别为4.06%和1.34%;当过热度较高时(75 ℃和105 ℃),钢液的热对流较为强烈,溶质元素上浮,使得铸锭凝固末端的偏析以及疏松情况又有所恶化。因此,通过铸锭偏析和疏松的定量分析可知,过热度55 ℃为最佳浇注工艺参数。

Original position statistic distribution analysis of GCr15SiMn bearing steel ingot

GCr15SiMn bearing steel ingots,which were cast after smelting in vacuum induction furnace,were investigated by original position statistic distribution analysis.The effects of degree of superheat on elemental segregation (C,Si,Mn and Cr) and porosity of ingot were analyzed.The results showed that:when the degree of superheat was relatively low (25 ℃),the obvious segregation and cavity shrinkage occurred at the end of solidification due to the large numbers of nucleation of solute elements in the front of solidification and the thermal convection difference of molten steel.The statistical segregation and statistical porosity of C was 7.83% and 1.76%,respectively.With the further increase of superheat (55 ℃),the heat convection of molten steel was strengthened,and the segregation of elements was improved to some extent.The statistical segregation and statistical porosity of C in ingot reached the minimum,i.e.,4.06% and 1.34%, respectively.When the superheat was relatively high (75 ℃ and 105 ℃),the thermal convection of the molten steel was strong.The solute elements floated up, which deteriorated the segregation and porosity at the solidification end of the ingot.Therefore,through the quantitative analysis of segregation and porosity of the ingot, the degree of superheat at 55 ℃ was the optimal process parameter for casting.