18Cr2Ni4W钢的热变形行为及热加工图  

Hot deformation behavior and hot processing map of 18Cr2Ni4W steel

作　　者：蔡述巧 王勇帆 陈克鑫 纪宏志 谷大鹏[1] 刘鑫刚[1] CAI Shu-qiao;WANG Yong-fan;CHEN Ke-xin;JI Hong-zhi;GU Da-peng;LIU Xin-gang(School of Mechanical Engineering,Yanshan University,Qinhuangdao 066004,China;No.703 Research Institute,China State Shipbuilding Company Limited,Harbin 150078,China)

机构地区：[1]燕山大学机械工程学院,河北秦皇岛066004 [2]中国船舶集团有限公司第七〇三研究所,黑龙江哈尔滨150078

出　　处：《材料热处理学报》2024年第7期201-211,共11页Transactions of Materials and Heat Treatment

基　　金：河北省自然科学基金绿色通道项目(E2021203074)。

摘　　要：在变形温度为850~1200℃,应变速率为0.005~0.5 s^(-1)及真应变为0.8的条件下,采用Gleeble-3800型热模拟试验机对18Cr2Ni4W钢进行热压缩试验,分析其真实应力-应变曲线,基于双曲正弦函数,建立了18Cr2Ni4W钢的热变形本构方程;采用动态材料模型(DMM),建立了18Cr2Ni4W钢在真应变为0.8时的热加工图。结果表明:18Cr2Ni4W钢在热加工过程中发生了动态再结晶,流变应力随着变形温度的升高而降低,随着应变速率的增加而增加;峰值应力随应变速率的降低和变形温度的升高而降低。失稳区主要集中分布于变形温度为860~950℃、应变速率为0.03~0.5 s^(-1)的范围内,其显微组织为沿变形方向拉长的带状组织,并存在局部流动性,对应的功率耗散η值较低,小于0.2;安全区的显微组织是典型动态再结晶组织,功率耗散η值较高,在0.28~0.49之间。在真应变为0.8时,18Cr2Ni4W钢最佳的热加工工艺为:变形温度为975~1050℃、应变速率为0.01~0.14 s^(-1)以及变形温度为1050~1200℃、应变速率为0.01~0.5 s^(-1)。Under the conditions of deformation temperature of 850-1200 ℃,strain rate of 0.005-0.5 s^(-1) and true strain of 0.8,the Gleeble-3800 thermal simulation testing machine was used to conduct hot compression tests on 18Cr2Ni4W steel.Based on the analysis of the true stress-strain curves and the hyperbolic sine function,the hot deformation constitutive equation of the 18Cr2Ni4W steel was established.Hot processing map of the 18Cr2Ni4W steel at true strain of 0.8 was established using a dynamic material model(DMM).The results show that the 18Cr2Ni4W steel undergoes dynamic recrystallization during hot processing,the flow stress decreases with the increase of deformation temperature and increases with the increase of strain rate,and the peak stress decreases with the decrease of strain rate and the increase of deformation temperature.The instability zone is mainly distributed within the range of deformation temperature of 860-950 ℃ and strain rate of 0.03-0.5 s^(-1),its microstructure is an elongated strip structure along the deformation direction,with local fluidity,and the corresponding power dissipation value η is low,less than 0.2.The microstructure of the safety zone is a typical dynamic recrystallization microstructure,with a high power dissipation value η between 0.28 and 0.49.The optimal hot working process for the 18Cr2Ni4W steel at true strain of 0.8 is:deformation temperature of 975-1050 ℃,strain rate of 0.01-0.14 s^(-1),and deformation temperature of 1050-1200 ℃,strain rate of 0.01-0.5 s^(-1).

关 键 词：18Cr2Ni4W钢 热变形行为 本构方程 热变形组织 热加工图 

分 类 号：TG142.7[一般工业技术—材料科学与工程]