摘要
连续冷却过程中的相变行为是决定淬火残余应力的关键要素。通过相变行为研究和显微组织观察研究了X510L钢连续冷却转变动力学规律。结果表明:冷速是决定相变动力学最关键的影响因素。随冷速增大,铁素体相变开始温度降低,相变时间缩短,且前期转变快于后期。建立了考虑冷速的铁素体相变动力学模型:ξ=1-exp[-b(Fs-T)(f(v))],弥补了传统相变动力学方程不考虑冷速影响的缺陷,模型中材料参数n对相变过程的影响更显著。运用上述相变动力学方程,结合现场实际冷却工艺分析X510L钢翘曲缺陷形成的原因,提出了基于铁素体钢翘曲控制的F7出口速度与冷速的匹配原则,并确定当F7出口速度为8 m/s时,将冷速范围设定为14.3~20℃/s可以避免X510L钢出现翘曲缺陷。借鉴上述方法,可以避免铁素体钢由于冷速设定不合理所导致的翘曲缺陷。
The phase transformation behavior during continuous cooling is the key factor to determine the quenching residual stress.The kinetics of continuous cooling transformation of X510L steel was studied by phase transformation behavior and microstructure observation.The results show that the cooling rate is the key factor to determine the phase transformation kinetics.With the increase of cooling rate,the starting temperature of ferrite transformation decreases,the transformation time shortens,and the transformation in the early stage is faster than that in the late stage.The ferrite transformation kinetics model considering the cooling rate is established:ξ=1-exp[-b(Fs-T)f(v)],which makes up the defect that the traditional transformation kinetics equation does not consider the influence of the cooling rate,and the material parameter n in the model has more significant influence on the transformation process.Using the above phase transformation dynamic equation and combining with the actual cooling process on site,the reason for the formation of the warping defect of the X510L steel is analyzed.The matching principle of F7 outlet speed and cooling rate based on the ferrite steel warping control is proposed.It is determined that when the F7 outlet speed is 8 m/s,the warping defect of the X510L steel can be avoided by setting the cooling rate range at 14.3-20℃/s.Using the above method for reference,the warping defect of ferrite steel caused by unreasonable cooling rate setting can be avoided.
作者
周莹涛
丁文红
彭冲
陈浩
唐小勇
龚红根
ZHOU Ying-tao;DING Wen-hong;PENG Chong;CHEN Hao;TANG Xiao-yong;GONG Hong-gen(The State Key Laboratory of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China;Xinyu Iron&Steel Co Ltd,Xinyu 338001,China)
出处
《材料热处理学报》
CAS
CSCD
北大核心
2023年第6期132-142,共11页
Transactions of Materials and Heat Treatment
基金
湖北省技术创新专项重大项目(2018AAA005)。
关键词
X510L钢
动态CCT
相变动力学
翘曲
残余应力
临界冷速
X510L steel
dynamic CCT
phase transformation kinetics
warping
residual stress
critical cooling rate
