【作者】 龚明亮；

【导师】 王华昌；

【作者基本信息】 武汉理工大学 ， 材料加工工程， 2007， 硕士

【摘要】 热锻模在服役过程中工况恶劣，其寿命普遍很低，从而直接影响了锻件的成本和生产单位的经济效益。热模锻在模锻行业占有主导地位，我国热锻模平均寿命与国际先进水平有较大差距。因此，如何提高模具的使用寿命，降低锻件成本是热加工行业中亟待解决的问题。热锻模同时承受周期性的热负荷与机械载荷，分别产生相应的热应力与机械应力。热应力是造成热锻模损伤失效的主要原因。因此，研究热锻模缓解热应力的机理和方法，为长寿命热锻模的材料设计及制备工艺提供热力学依据具有重要社会经济意义。本文理论研究了热锻模的温度分布与热传递特性；热锻模型腔表面的峰值温度；模具表面层与近表面层间的温度差峰值；推导出了热锻模峰值热应力的理论表达及参数表达；根据公式中的影响参数，分析了缓解热应力的机理，提出了缓解热锻模热应力的方法并应用有限元分析软件DEFORM-2D进行了验证；为制造长寿命热锻模初步提出了理论指导与制造方法。本文提出的缓解热锻模的热应力四个方法如下：减小模具型腔危险点表面层与近表面层间的温度差值；选用更好的热锻模具材料；开发使用功能性新材料；改善工艺参数。在介绍了目前双金属热锻模的研究基础上，提出了梯度功能热锻模与多金属热锻模的概念，介绍了在生产实践中更容易实现的多金属热锻模及其结构与制造方法。并在热锻模选材、材料(组份)设计、热锻模结构设计、制造方法上提出了新的思路。更多还原

【Abstract】 The working condition of hot forging die is very bad, its service life is very lowgenerally. The cost of the pieces and the economic efficiency of the manufactory wereaffected directly. The impact forging holds the dominant position in the forgingprofession. There is a bigger disparity between average service life of hot forging dieof our country and the international advanced level. Therefore, how to enhance theservice life of hot forging die and how to reduce cost of the pieces are the questionsof hot forging profession awaiting to be solved urgently.The hot forging die simultaneously withstands the periodic thermal load and themechanical load, which causes thermal stress and mechanical stress separately. Thethermal load is the main reason which causes damage of hot forging die. Therefore,this means the important social economic significance to study the mechanism andthe methods to alleviate thermal stress of hot forging die and providesthermodynamics basis theroy on material design and the manufacture craft for the hotforging die which has long service life.The following topics were studieded in this dissertation. These topics include:the temperature distribution and heat transfer characteristic of hot forging die; thepeak temperature of mold cavity surface layer; temperature difference peak betweencavity surface layer and near surface layer; theory expression on peak thermal stressof hot forging die. The methods to alleviate thermal stress of hot forging dieaccording to influential parameters of the formula about thermal stress, and thesimulation using the DEFORM-2D program were analysed. The preliminary theoryinstruction and the manufacture methods for making the hot forging die which haslong service life were proposed in this dissertation.The methods to alleviate the thermal stress of hot forging die proposed in thisdissertation are as followings: reduceing temperature difference value between themold cavity surface layer and the near surface layer; selecting the better hot forgingdie material; developing new function material; improving craft parameters.The concepts of the gradient function hot forging die and the polymetallic hotforging die was proposed on the foundation of bimetallic hot forging die. The polymetallic hot forging die which could be realized easier in production practice andits structure and manufacture method were introduced. New idea about selectionmatreials, the material component designning, the structural designning and the.manufacture method of hot forging die was introduced.更多还原