摘要
堆焊层表面不可避免地存在孔洞、半埋藏裂纹缺陷,理论分析与数值模拟表明,缺陷会引起应力集中,当裂纹尖端的应力强度因子值达到断裂韧性时,裂纹会失稳扩展,导致材料的实际断裂强度远低于该材料的理论断裂强度,使构件很快失效。激光熔覆利用高能量的激光束使存在缺陷的堆焊层表面熔化再结晶,并用合金粉末在表面涂覆一层合金层,实验研究发现,堆焊层与熔覆层呈冶金结合,熔覆层并未影响到堆焊层高硬度的特性。超声波无损检测结果表明,堆焊层表面的孔洞、半埋藏裂纹缺陷已基本被消除,达到了强化与修复的目的。
Hardfacing layer surface inevitable retains holes and half buried crack defects,the theoretical analysis and numerical simulation shows that defects can cause stress concentration,when the stress intensity factor at the crack tip reach to the fracture toughness,crack will instability propagates and lead to that the actual rupture strength far lower than the theoretical rupture strength of material,that make component soon failure.Laser cladding with high energy laser beam make the surface defects of hardfacing layer to melting recrystallization and coat an alloy layer on the surface.Experimental study found that hardfacing layer and cladding layer is metallurgical bind,cladding layer does not affect the characteristics of high hardness of hardfacing layer,Ultrasonic nondestructive testing results show that holes and half buried crack defects at the surface of hardfacing layer has basically eliminated,get the purposes of strengthen and restoration.
出处
《金属热处理》
CAS
CSCD
北大核心
2011年第12期95-97,共3页
Heat Treatment of Metals
基金
国家自然科学基金项目(51075351)
关键词
孔洞
裂纹
激光熔覆
无损检测
holes
crack
laser cladding
nondestructive testing
