摘要
以Ueshima的正六边形横断面枝晶模型为原型,采用有限差分方法建立了钢凝固过程伴随δ/γ相变的两相区溶质微观偏析模型,浅析了冷却速率10℃/s非平衡凝固条件下,钢的脆性温度区内各溶质元素的偏析特点,并定量给出不同P、S含量下,脆性温度区临界断裂应变和临界断裂应力随C含量的变化规律。结果表明,C、P、S偏析对连铸坯凝固前沿裂纹敏感性影响显著,钢液P、S初始含量的增加显著降低脆性温度区临界断裂应变,小幅提高钢在fs=1.0处的临界断裂应力,而且引起脆性温度区内固相分率和相组成的显著变化,抗拉强度下降。
Based on the regular hexagon transverse cross section of dendrite shape proposed by Ueshima, a microsegregation model of solute elements in mushy zone with δ/γ transformation during solidification was established by finite difference method. The characteristics of each solute element segregation at the brittle temperature range under the non-equilibrium solidification condition at 10 ℃/s of cooling rate was analyzed. Also, the variations of critical fracture strain and critical fracture stress at different contents of P and S with carbon content were given qualitatively. The results show that the effects of C, P and S segregation on crack susceptibility at solidification front of continuous casting strand was significant. Increasing the contents of P and S in molten steel will decrease the critical fracture strain drastically and increase the critical fracture stress a bit. Moreover, the segregation of P and S due to the increasing of their initial contents in steel gives rise to the change of solidification fraction and component of phase which induces tensile strength reduction.
出处
《铸造技术》
CAS
北大核心
2009年第11期1396-1401,共6页
Foundry Technology
基金
教育部新世纪优秀人才支持计划项目NCET-04-0285资助
关键词
连铸
微观偏析
裂纹敏感性
临界断裂应变
临界断裂应力
Continuous casting
Microsegregation
Crack susceptibility
Critical fracture strainCritical fracture stress
