激光技术
激光技術
격광기술
LASER TECHNOLOGY
2013年
4期
547-550
,共4页
激光技术%Ni基合金%有限元方法%温度场%凝固理论
激光技術%Ni基閤金%有限元方法%溫度場%凝固理論
격광기술%Ni기합금%유한원방법%온도장%응고이론
laser technique%Ni-based alloy%finite element method%temperature field%solidification theory
为了分析预置粉末Ni基合金熔覆过程的温度场和熔池的结晶变化规律，采用有限元方法建立了激光熔覆Ni基合金粉末过程的3维模型，考虑温度变化对热物理参量的影响以及表面对流换热和辐射散热等影响因素，使用SYSWELD软件对激光熔覆过程中的温度场和凝固结晶过程进行了分析及验证。结果表明，最高温度位于光斑中心处，等温线近似椭圆形，并且向外逐渐减小；熔覆层上某点热循环峰值温度随着热源的远离而明显降低，且热循环起始由第1道次的室温增大到最后道次的730℃；形状因子有结合界面处的1.9×109℃?s?mm-2降到熔覆层表面处的0.7×109℃?s?mm-2，同时，二次枝晶的间距在结合面处最大，表面处达到最小值，与相同工艺参量下的金相组织和凝固结晶理论完全吻合。该研究结果为激光熔覆过程的优化提供了指导意义。
為瞭分析預置粉末Ni基閤金鎔覆過程的溫度場和鎔池的結晶變化規律，採用有限元方法建立瞭激光鎔覆Ni基閤金粉末過程的3維模型，攷慮溫度變化對熱物理參量的影響以及錶麵對流換熱和輻射散熱等影響因素，使用SYSWELD軟件對激光鎔覆過程中的溫度場和凝固結晶過程進行瞭分析及驗證。結果錶明，最高溫度位于光斑中心處，等溫線近似橢圓形，併且嚮外逐漸減小；鎔覆層上某點熱循環峰值溫度隨著熱源的遠離而明顯降低，且熱循環起始由第1道次的室溫增大到最後道次的730℃；形狀因子有結閤界麵處的1.9×109℃?s?mm-2降到鎔覆層錶麵處的0.7×109℃?s?mm-2，同時，二次枝晶的間距在結閤麵處最大，錶麵處達到最小值，與相同工藝參量下的金相組織和凝固結晶理論完全吻閤。該研究結果為激光鎔覆過程的優化提供瞭指導意義。
위료분석예치분말Ni기합금용복과정적온도장화용지적결정변화규률，채용유한원방법건립료격광용복Ni기합금분말과정적3유모형，고필온도변화대열물리삼량적영향이급표면대류환열화복사산열등영향인소，사용SYSWELD연건대격광용복과정중적온도장화응고결정과정진행료분석급험증。결과표명，최고온도위우광반중심처，등온선근사타원형，병차향외축점감소；용복층상모점열순배봉치온도수착열원적원리이명현강저，차열순배기시유제1도차적실온증대도최후도차적730℃；형상인자유결합계면처적1.9×109℃?s?mm-2강도용복층표면처적0.7×109℃?s?mm-2，동시，이차지정적간거재결합면처최대，표면처체도최소치，여상동공예삼량하적금상조직화응고결정이론완전문합。해연구결과위격광용복과정적우화제공료지도의의。
In order to analyze the rules of temperature field and molten pool crystalline diversification during the preset powder Ni-based alloy cladding process , a 3-D model of laser cladding was made with finite element method .Taking consideration of the impact of temperature changes on the thermal physical parameters and the effects of heat convection and radiation heat, temperature field and solidification and crystallization of laser cladding process were analyzed and verified by SYSWELD software.The results show that the highest temperature is at the spot center , the isothermal line is almost elliptical and the temperature declines gradually along the radius of the spot center .Thermal cycle peak temperature at a certain point on the coating reduced significantly as the heat source was away .The temperature increased from the room temperature at the first pass to 730℃ at the final pass.Shape factor is reduced from 1.9 ×10 9℃?s?mm-2 of bonding surface to 0.7 ×10 9℃?s?mm-2 of cladding surface.At the same time, secondary dendrite spacing is the biggest at the bonding surface and the smallest at the cladding surface .The calculation results are perfectly matched with metallographic microstructure and solidification and crystallization theory .The results provide theoretical guidance for the optimization of laser cladding
