基于原位观察的H13钢中液析碳化物高温行为研究

使用原位观察方法研究了不同凝固条件H13钢铸锭样品中液析碳化物的高温行为.实验发现连铸锭及电渣锭两种样品在所研究的枝晶间存在明显的合金元素偏析,其中Cr、Mo、V、C的偏析较为明显,液析碳化物存在于凝固枝晶间偏析最严重的区域,成分为V、Mo、Cr、Ti的液析碳化物.连铸锭及电渣锭两种样品分别在1200℃ 及1250℃ 围绕液析碳化物周围出现局部液相,理论计算的局部液相出现温度与实验观察到的接近;随着温度的升高,局部液相范围扩大,与电渣锭相比,加热至相同温度时,连铸锭液析碳化物周围的局部液相范围更大.液析碳化物周围局部液相的出现加快了枝晶间合金元素的扩散,对液析碳化物的高温行为具有重要影响.

In-situ research of high-temperature behavior of primary carbide in H13 steel

In-situ research was conducted to illuminate the high-temperature behavior of primary carbide in H13 steel that had been cast in different ways. Experimental observations indicate the obvious segregation of Cr, Mo, V, and C in the interdendrite zone of continuously cast and electroslag remelting (ESR) samples. In the interdendrite zone, primary carbide is composed of Cr, Mo, V, and Ti. A liquid phase was observed to occur around the primary carbide of two as-cast samples cast by continuous casting and ESR processes when heated to 1200 ℃ and 1250 ℃ , respectively. The temperature at which the liquid phase appears agrees well with theo-retical calculations. The liquid-phase region expands as the heating temperature increases and the continuous casting sample shows a larger liquid zone. The emergence of a partial liquid phase accelerates the diffusion of the segregated elements and is an important fac-tor in the high-temperature behavior of primary carbide.