摘要
利用高温热处理炉,分析了轧制前热处理对 301L不锈钢铸坯的溶解行为.结果表明,退火时间和温度对δ铁素体在 301L铸坯中的溶解影响显著,溶解初期,δ铁素体的含量从 12wt%降至 6wt%以下.随着退火时间的延长和温度的升高,301L铸坯固态中δ铁素体含量减少,受Cr、Ni的扩散控制显著,1300℃扩散退火 60 min后铁素体球化,晶粒尺寸减小为 2～3 μm,节点处平衡态δ铁素体的球化行为降低了γ/α界面的附加应力,有利于轧制过程.利用动力学方程验证了后期Cr、Ni元素对组织的影响,当退火温度为 1210℃时,溶解参数KγNi为 0.26,Ni的扩散系数D γNiNi=4.8×10-10 cm2/s.δ铁素体的体积分数与退火时间t1/2 成正比.研究结果可为 301L铸坯的组织控制提供理论指导.
Abstract
The dissolution behavior of 301L stainless steel casting billet by heat treatment furnace before rolling was analyzed.The results show that the dissolution of δ ferrite in 301L billet is significantly affected by annealing time and temperature.At the beginning of dissolution,the content of δ ferrite decreases from 12wt%to less than 6wt%.With the increase of annealing time and temperature,the decrease of δ ferrite content in the solid state of 301L billet is significantly controlled by the diffusion of Cr and Ni.After diffusion annealing at 1300℃for 60 min,ferrite spheroidized and the grain size decreases to 2-3 μm.The spheroidization behavior of the equilibrium δ ferrite at the node reduces the additional stress at the γ/α interface and facilitates the rolling process.The effects of Cr and Ni on the microstructure are verified by the kinetic equation.When the annealing temperature is 1210℃,the dissolution parameter KγNi is 0.26,and the diffusion coefficient of Ni is D γNiNi=4.8×10-10 cm2/s.The volume fraction of δ ferrite is proportional to the annealing time t1/2.The research results can provide theoretical guidance for the microstructure control of 301L casting billet.
基金项目
甘肃省科技计划(创新基地和人才计划)项目(17JR5RA131)
甘肃省科技计划(科技重大专项)项目(17ZD2GB012)
NETL
NSTL
万方数据