庞铭,谭雯丹.预热温度对激光熔凝RuT300气门座残余应力场的影响研究[J].表面技术,2019,48(8):296-301.
PANG Ming,TAN Wen-dan.Effect of Preheating Temperature on Residual Stress Field of Laser Melting RuT300 Valve Seats[J].Surface Technology,2019,48(8):296-301 |
| 预热温度对激光熔凝RuT300气门座残余应力场的影响研究 |
| Effect of Preheating Temperature on Residual Stress Field of Laser Melting RuT300 Valve Seats |
| 投稿时间：2018-11-23 修订日期：2019-08-20 |
| DOI：10.16490/j.cnki.issn.1001-3660.2019.08.039 |
| 中文关键词: 激光熔凝 预热温度 RuT300 气门座 残余应力 裂纹抑制 |
| 英文关键词:laser melting preheating temperature RuT300 valve seats residual stress crack suppression |
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| 中文摘要: |
| 目的 为了突破激光熔凝蠕墨铸铁RuT300气门座裂纹抑制技术的瓶颈，研究了预热温度对激光熔凝RuT300气门座残余应力场的影响，从而为工程上抑制裂纹的参数优选提供支撑。方法 基于热弹塑性理论，建立了激光熔凝RuT300气门座残余应力场分析的数学物理模型，模型中考虑了预热温度、激光熔凝参数、材料性能参数的变化对残余应力的影响。结果 预热温度对激光熔凝RuT300气门座残余应力场的影响与熔池冷却速度、峰值温度等密切相关：当预热温度在25~150 ℃时，随着预热温度的升高，冷却速度下降对激光熔凝RuT300气门座热膨胀变形引起的应力降低起主要作用，导致气门座环向残余应力值随预热温度的升高而减小；当预热温度在150~250 ℃时，随着预热温度的升高，峰值温度上升诱发的热膨胀变形加剧所引起的应力增加起主要作用，导致气门座环向残余应力值随预热温度的升高而增大。结论 预热温度的变化影响气门座的冷却速度和峰值温度，而残余应力值的变化是气门座冷却速度和峰值温度等综合影响的结果，通过合理的调控预热温度，可以使激光熔凝RuT300气门座的残余应力值降低到最低，从而减小气门座激光熔凝形成裂纹的倾向。 |
| 英文摘要: |
| The work aims to study the effect of preheating temperature on residual stress field of laser melting RuT300 valve seats, so as to break through the bottleneck of crack suppression technology of laser melting valve seats made of vermicular graphite cast iron RuT300 and provide support for parameter optimization of crack suppression in engineering. Based on the thermal elastoplastic theory, a mathematical and physical model for residual stress field analysis of laser melting RuT300 valve seats was established. The effects of preheating temperature, laser melting parameters and changes of material performance parameters on residual stress were considered in the model. The effect of preheating temperature on residual stress field of laser melting RuT300 valve seats was closely related to the cooling rate of molten pool, the peak temperature, etc. When the preheating temperature was between 25 ℃ and 150 ℃, stress reduction due to the mismatch of thermal expansion deformation in space of laser melting RuT300 valve seats caused by the decrease of cooling rate with the increase of preheating temperature played a major role, thus decreasing circumferential residual stress value of valve seats with the increase of preheating temperature. When the preheating temperature was between 150 ℃ and 250 ℃, the increase of stress caused by the intensified thermal expansion deformation induced by the peak temperature rise with the increase of preheating temperature played a major role, resulting in the increase of circumferential residual stress value of valve seats with the increase of preheating temperature. The variation of preheating temperature affects the cooling rate and the peak temperature of valve seats, and the variation of residual stress value is the result of the combined effect of cooling rate and peak temperature of valve seats. By adjusting and controlling the preheating temperature reasonably, the residual stress value of laser melting RuT300 valve seats can be reduced to the minimum, thus reducing the tendency of crack formation of laser melting valve seats. |
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