摘要
考虑材料热物性参数和对流换热系数的非线性,以空气、纯水和2#分级油为介质环境,采用连续气流保护熔池,建立基体浸没式激光动态热加工过程的三维数值模型,对不同自然冷却介质中基体热响应温度场及残余应力场进行对比研究。结果表明,三种环境中的温度场规律基本一致,空气中基体温度最高。表面高温区域油冷效果明显,低温区水冷效果明显;油冷环境可有效控制重熔区和热影响区深度,而水冷环境材料表面可获得更大的温度梯度和冷却速度。不同介质环境对残余应力分布影响显著:空冷基体内部应力过大,且在两端应力有集中,整体以拉应力为主,而水、油环境中的热应力得到了及时释放,其中水冷环境对降低残余应力更为有效。
Under the consideration of the nonlinearity of the material thermal parameters and heat convective transfer coefficient,a validated three-dimensional numeric modal of laser heat dynamic process was established with base body immersed in the medium surroundings such as air,pure water and 2# martempering oil using air stream for protecting the melten pool,the field of temperature and residual stress of thermal response within different natural cooling media were studied comparatively.The results showed that,the law of the temperature field is essentially consistent with three kinds of surroundings,and the substrate highest temperature appeared in the air.The surface high and low temperature region were effected obviously by oil-cooling and water-cooled respectively;the remelting and heat-affected depth could be controlled effectively by oil-cooled,while larger temperature gradient and cooling rate would be gained within water.Residual stress distribution was affected significantly by medium surroundings.Internal stress of substrate was too large with air-cooled and there was stress concentration at both ends and the tensile stress was main.While substrate thermal stress had been released timely in water and oil surroundings,and water-cooled environment was more effective in reducing the residual stress.
出处
《中国激光》
EI
CAS
CSCD
北大核心
2010年第10期2642-2647,共6页
Chinese Journal of Lasers
基金
国家863计划(2006AA09A104)
山东省自然科学基金(Y2007F76)
新疆克拉玛依市科技攻关项目(SK2008-52)资助课题
关键词
激光技术
浸没式
激光热加工
介质环境
温度场
残余应力分布
laser technique
immersion model
laser heat processing
medium surrounding
temperature field
residual stress distribution
