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大型锻件锻造镦粗表面无开裂条件

CONDITION OF LARGE FORGINGS UPSETTING WITHOUT SIDE SURFACE CRACKING OF INGOT

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【作者】 任运来朱磊王子亮聂绍珉

【机构】 燕山大学机械工程学院

【摘要】 镦粗是大型锻件锻造的基本工序,防止侧表面开裂在理论上和生产中都有非常重要的意义。为描述镦粗过程变形的不均匀程度,将损伤力学的临界空穴扩张比理论用于镦粗变形表面开裂的研究中;引入了瞬时鼓形系数的概念,数值计算表明: 在给定的端面摩擦条件下,相对压下量是影响瞬时鼓形系数数值大小的因素;镦粗过程中鼓形顶点处纬向应力、经向应力仅是瞬时鼓形系数的函数;从而得到了损伤力学变量应力三轴度与不均匀变形程度变量瞬时鼓形系数的关系。借助临界空穴扩张比理论和塑性力学方程,建立大型锻件锻造镦粗表面无开裂条件。实验表明该条件是正确的。

【Abstract】 Upsetting is the basic process of large Forgings producing.It’s important to prevent side surface cracking of ingot during upsetting in theory and application.Instantaneous drum coefficient is given to describe the degree of inhomogeneous deformation during upsetting and to draw the theory of critical hole expansion ratio in damage mechanics into the study of side surface cracking of ingot.Numerical calculation shows that in the condition of invariable end surface friction the value of instantaneous drum coefficient is influenced only by the relative pressing volume.Longitudinal stress and latitude stress is only the function of instantaneous drum coefficient during upsetting.By ways above,the relation between the stress triaxiality and instantaneous drum coefficient is obtained.By means of the theory of critical hole expansion ratio and plastic equation,condition of large forgings upsetting without side surface cracking of ingot is set up.The experiment indicated the condition is correct.

【关键词】 大锻件锻造镦粗损伤力学
【Key words】 Large forgingsForgeUpsettingDamage
  • 【会议录名称】 2008年中国机械工程学会年会暨甘肃省学术年会文集
  • 【会议名称】2008年中国机械工程学会年会暨甘肃省学术年会
  • 【会议时间】2008-07
  • 【会议地点】中国甘肃兰州
  • 【分类号】TG316
  • 【主办单位】中国机械工程学会、甘肃省人民政府
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