摘要
对含有裂纹的金属构件进行脉冲放电止裂时 ,裂纹尖端由于电流的绕流热集中效应 ,在瞬间使裂尖熔化形成焊口。由于裂尖附近超快速加热和冷却 ,金属材料完成了一次超高速冲击淬火。采用数值模拟计算了脉冲放电超快速加热时裂纹尖端温度场、温度梯度场 ;通过脉冲放电止裂试验研究了裂尖超高速淬火全过程。通过对止裂后裂尖的金相组织观察和微观机理分析发现 :超细化的条状马氏体、极少量残留奥氏体和细颗粒碳化物的出现明显提高了裂纹尖端的硬度。
The crack arresting has been executed in metal component with crack through pulse current discharge.During current discharge,the crack tip is melted,and then a welded joint formed.Because of super rapid heating and cooling while pulse current is switched on,the super high speed impact quenching is accomplished around crack tip.The temperature field and temperature gradient field near the crack tip during crack arresting were obtained by numerical simulation.The super high speed impact quenching was studied with experiment of crack arresting through pulse current discharge.The microstructure was analyzed around crack tip after crack arresting.The superfine strip martensite,fine grained carbon compound and residual austenite was found around crack tip.The intensity,ductility and wearing capacity around crack tip have been promoted under the influence of superfine structure.
出处
《金属热处理》
CAS
CSCD
北大核心
2002年第3期29-31,共3页
Heat Treatment of Metals
基金
河北省自然科学基金 (5992 55)
国家自然科学基金项目(1 9772 0 4 6)
