t_(8/5)对NM400耐磨钢焊接粗晶区组织和性能的影响  

Effect of t_(8/5) on Microstructure and Properties of Welding Coarse Grain Region of NM400 Wear-resistant Steel

作　　者：佘人杰 张波 肖爱达[2] 周剑丰[2] 刘宁 梁文 SHE Renjie;ZHANG Bo;XIAO Aida;ZHOU Jianfeng;LIU Ning;LIANG Wen(School of Materials and Advanced Manufacturing,Hunan University of Technology,Zhuzhou 412000,China;Hunan Valin Lianyuan Iron and Steel Co.,Ltd.,Loudi 417000,China)

机构地区：[1]湖南工业大学材料与先进制造学院,湖南株洲412000 [2]湖南华菱涟源钢铁有限公司,湖南娄底417000

出　　处：《热加工工艺》2025年第3期56-59,64,共5页Hot Working Technology

基　　金：湖南省重点研发计划项目(2023GK2085)。

摘　　要：利用MMS-200热模拟试验机,通过金相组织观察及硬度检测等方法,研究了不同t_(8/5)条件下NM400耐磨钢焊接粗晶区显微组织及硬度的变化规律,并获得了热影响区的连续冷却转变曲线。结果表明:高温转变区析出先共析铁素体,中低温区域发生贝氏体和马氏体转变;t_(8/5)≤10 s时,硬度变化不大,组织主要为板条马氏体;当t_(8/5)>10 s时,随着t_(8/5)时间的增加,硬度显著降低,板条马氏体数量逐渐减少,贝氏体数量增加;当t_(8/5)=60 s时,马氏体组织消失,60~150 s区间组织主要为贝氏体;当t_(8/5)=150 s时,析出铁素体,且板条贝氏体逐步转变为粒状贝氏体。根据SH-CCT曲线分析,NM400耐磨钢焊接时应严格控制线能量,控制t_(8/5)≤10 s,以保证焊接接头的强度。Using MMS-200 thermal simulation testing machine,the change law of microstructure and hardness of NM400 wear-resistant steel welded coarse grain area under different t_(8/5) conditions was studied,and the continuous cooling transition curve of the heat affected zone wsa obtained through the methods of metallographic structure observation and hardness testing.The results show that proeutectoid ferrite is precipitated in the high temperature transformation zone,and bainite and martensite transformation occurs in the middle and low temperature zone.When t_(8/5)≤10 s,the hardness value does not change much,and the structure is mainly lath martensite.When t_(8/5)>10 s,with the increase of t_(8/5) time,the hardness decreases significantly,the number of lath martensite gradually decreases,and the number of bainite increases.When t_(8/5)=60 s,the martensite structure disappears,and the structure in the interval of 60-150 s is mainly bainite.When t_(8/5)=150 s,ferrite is precipitated,and lath bainite gradually transforms into granular bainite.According to the SH-CCT curve,NM400 wear-resistant steel should strictly control the line energy during welding,and by controling t_(8/5)≤10 s,the strength of the welded joint showld be ensured.

关 键 词：焊接热模拟 粗晶区 SH-CCT图 NM400耐磨钢 硬度 

分 类 号：TG151.2[金属学及工艺—热处理] TG406[金属学及工艺—金属学]