应用镁蒸气对模具钢中夹杂物变性的研究

Inclusions Modification in Die Steel with Magnesium Vapor

D2冷作模具钢最常见的失效形式为磨损失效,改善夹杂物的数量、形态和分布能降低钢的磨损率.利用颗粒镁在高温下生成镁蒸气,并通过高纯氩气携带通入钢液中,考察了镁对钢中非金属夹杂物的变性效果.实验结果表明,镁蒸气通入钢液后,钢中非金属夹杂物尺寸明显变得细小,夹杂物的成分从单纯的Al2O3和Al2O3与Cr,Mo和V等合金氧化物的复合产物向富MgO的MgO和Al2O3复合夹杂物转变.铸态组织的观察结果表明细小夹杂物在钢液中的残存对于凝固和相变过程中钢的晶粒细化有利.

Wear failure is the most common failure mode for D2 cold working die steels. The wear rate of the steel decreases by reducing the number of the inclusions and by improving the morphology and distribution of them. The granular magnesium was used to generate magnesium vapor at high temperatures, and the vapor was carded into the molten steel by high purity argon gas. The effects of magnesium on non-metallic inclusions modification were discussed. The results showed that the size of non-metallic inclusions in the steel were obviously finer with the magnesium vapor flowing into molten steel than that without it. The composition of inclusions changed from pure alumina inclusions or compound of Al2O3 and the oxide of element Cr, Mo and V to alumina-magnesia complex inclusions. The observation of as-cast microstructure showed that small inclusions remained in the steel were benefit for grain refining in the process of solidification and phase transitions.