丝锥淬火冷却过程温度场应力场模拟
发布时间：2018-12-31 17:47
【摘要】：丝锥作为一种重要的内螺纹加工刀具,在机械制造中起到重要的作用。由于丝锥的结构特别是丝锥螺纹牙部分,决定了丝锥在热处理过程中特别是淬火冷却过程中会出现较大的应力,容易造成变形和开裂等现象。因此对丝锥进行淬火冷却过程的数值模拟,模拟其温度场和应力场,可以避免产生各种热处理缺陷。本文通过利用计算机数值模拟技术,综合传热学理论和热弹塑性相关知识,采用A nsy s有限元分析软件,建立了丝锥淬火冷却过程的三维有限元模型,计算中考虑了材料的热物性参数和冷却介质参数随温度的变化,利用热-力耦合的方法,计算出丝锥淬火冷却过程的温度场和应力场,分析了组织场。通过对M1 0×1.5丝锥在油介质下淬火冷却过程进行数值模拟计算,得出丝锥温度分布为表面温度低,心部温度高;应力场分布为切削刃尖处的等效应力最小,切削刃槽底部的等效应力最大,应力先增大后减小,在1 s左右时等效应力达到最大值3 09 MPa。残余应力最大处也是出现在螺纹根部,为5.0 6 MPa。对不同尺寸、不同材料的丝锥在不同冷却介质下进行淬火冷却过程的数值模拟计算,得出工件尺寸越小,冷却速度越快,内外温差越小,因此淬火冷却过程中的应力也越小,残余应力也越小;不同材料的热传导系数对淬火冷却过程中的温度影响较大,热传导系数越大,内层热量向外层传递越快,内外层温差越小,使得工件的内应力小。因此对于热传导系数大的材料可以采用冷却速度更快的冷却介质;不同冷却介质的对流换热系数对淬火冷却过程中的温度影响较大,对流换热系数越大,工件表面的热量很快通过介质的对流而传递到冷却介质中,使工件表面温度迅速降低,内外层温差大,内应力大。
[Abstract]:As an important internal thread cutting tool, tap plays an important role in mechanical manufacturing. Due to the structure of the tap, especially the thread part of the tap, it is decided that the taps will appear large stresses during heat treatment, especially during quenching and cooling, which will easily lead to deformation and cracking. Therefore, various heat treatment defects can be avoided by simulating the temperature field and stress field of the tap by numerical simulation of quenching and cooling process. In this paper, a three-dimensional finite element model of the quenching cooling process of a tap is established by using the computer numerical simulation technology, integrating the theory of heat transfer and thermoelastic-plastic knowledge, and using the A nsy s finite element analysis software. The temperature field and stress field of the tap quenching process are calculated by using the thermal-mechanical coupling method, and the microstructure field is analyzed by taking into account the variation of the material's thermal physical properties and the cooling medium parameters with temperature. Through the numerical simulation of quenching and cooling process of M10 脳 1.5 tap in oil medium, it is concluded that the temperature distribution of tap is low surface temperature and high core temperature. The stress field is distributed as the minimum equivalent stress at the cutting edge tip, and the maximum equivalent stress at the bottom of the cutting edge groove. The stress first increases and then decreases, and the equivalent stress reaches the maximum value of 309 MPa. at about 1 s. The maximum residual stress was also found at the thread root at 5.06 MPa. The numerical simulation of quenching and cooling process of tap with different sizes and materials in different cooling medium shows that the smaller the size of workpiece, the faster the cooling rate and the smaller the temperature difference between inside and outside, so the stress in quenching cooling process is smaller. The smaller the residual stress is; The heat conduction coefficient of different materials has a great influence on the temperature during quenching and cooling. The larger the heat conductivity coefficient is, the faster the inner layer heat is transferred to the outer layer and the smaller the temperature difference between the inner and outer layers, which makes the internal stress of the workpiece smaller. Therefore, the cooling medium with faster cooling rate can be used for the material with large thermal conductivity. The convection heat transfer coefficient of different cooling medium has a great influence on the temperature during quenching and cooling. The greater the convection heat transfer coefficient, the heat on the workpiece surface is quickly transferred to the cooling medium through the convection of the medium, and the surface temperature of the workpiece decreases rapidly. The inside and outside layer temperature difference is big, the internal stress is big.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG162.2
本文编号：2396910
[Abstract]:As an important internal thread cutting tool, tap plays an important role in mechanical manufacturing. Due to the structure of the tap, especially the thread part of the tap, it is decided that the taps will appear large stresses during heat treatment, especially during quenching and cooling, which will easily lead to deformation and cracking. Therefore, various heat treatment defects can be avoided by simulating the temperature field and stress field of the tap by numerical simulation of quenching and cooling process. In this paper, a three-dimensional finite element model of the quenching cooling process of a tap is established by using the computer numerical simulation technology, integrating the theory of heat transfer and thermoelastic-plastic knowledge, and using the A nsy s finite element analysis software. The temperature field and stress field of the tap quenching process are calculated by using the thermal-mechanical coupling method, and the microstructure field is analyzed by taking into account the variation of the material's thermal physical properties and the cooling medium parameters with temperature. Through the numerical simulation of quenching and cooling process of M10 脳 1.5 tap in oil medium, it is concluded that the temperature distribution of tap is low surface temperature and high core temperature. The stress field is distributed as the minimum equivalent stress at the cutting edge tip, and the maximum equivalent stress at the bottom of the cutting edge groove. The stress first increases and then decreases, and the equivalent stress reaches the maximum value of 309 MPa. at about 1 s. The maximum residual stress was also found at the thread root at 5.06 MPa. The numerical simulation of quenching and cooling process of tap with different sizes and materials in different cooling medium shows that the smaller the size of workpiece, the faster the cooling rate and the smaller the temperature difference between inside and outside, so the stress in quenching cooling process is smaller. The smaller the residual stress is; The heat conduction coefficient of different materials has a great influence on the temperature during quenching and cooling. The larger the heat conductivity coefficient is, the faster the inner layer heat is transferred to the outer layer and the smaller the temperature difference between the inner and outer layers, which makes the internal stress of the workpiece smaller. Therefore, the cooling medium with faster cooling rate can be used for the material with large thermal conductivity. The convection heat transfer coefficient of different cooling medium has a great influence on the temperature during quenching and cooling. The greater the convection heat transfer coefficient, the heat on the workpiece surface is quickly transferred to the cooling medium through the convection of the medium, and the surface temperature of the workpiece decreases rapidly. The inside and outside layer temperature difference is big, the internal stress is big.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TG162.2
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