NM450耐磨钢焊接粗晶区的组织及性能  

Microstructure and Properties of CGHAZ in NM450 Wear Resistant Steel

作　　者：斯松华[1] 徐震霖 方俊飞[1] 唐怀光 

机构地区：[1]安徽工业大学材料科学与工程学院,安徽马鞍山243000

出　　处：《热加工工艺》2015年第9期196-198,202,共4页Hot Working Technology

摘　　要：利用Gleeble-3500型热模拟试验机,进行NM450在不同热循环条件下的焊接热模拟试验,研究了t8/5对焊接热影响区粗晶区组织及性能的影响。结果表明:一次热循环t8/5从5 s增加到20 s时,粗晶区硬度逐渐下降,而冲击吸收功(-20℃)先增加后下降;当t8/5为15 s时,粗晶区冲击吸收功最高(46 J),冲击断口为准解理和微孔聚集混合型断裂,这是由于形成了板条马氏体和针状下贝氏体的混合组织,且马氏体发生了自回火。此钢种进行单道次焊接时,t8/5应控制在15 s左右。The welding thermal simulation experiment for NM450 with different thermal cycle was done by Gleeble-3500 thermal simulator. The effects of t8/5on the microstructure and properties of coarse-grained heat-affected zone（CGHAZ）were studied. The results show that, as the t8/5increases from 5 s to 20 s in single-pass welding thermal cycle, the hardness of CGHAZ decreases gradually, while the impact energy（-20 ℃） increases first and then decreases. The coarse grain zone has the highest impact energy（46 J） when t8/5is 15 s, and the impact fracture consists of quasi-cleavage fracture and micro-porous aggregation toughness fracture. Because the structure is composed of a lath martensite and acicular lower bainite, and the martensite has self-tempered. The t8/5for the steel should be about 15 s in single-pass welding.

关 键 词：耐磨钢 粗晶区 组织 性能 

分 类 号：TG406[金属学及工艺—焊接]