絲錐淬火冷卻過程溫度場應力場模擬
發(fā)布時間：2018-12-31 17:47
【摘要】：絲錐作為一種重要的內(nèi)螺紋加工刀具,在機械制造中起到重要的作用。由于絲錐的結(jié)構(gòu)特別是絲錐螺紋牙部分,決定了絲錐在熱處理過程中特別是淬火冷卻過程中會出現(xiàn)較大的應力,容易造成變形和開裂等現(xiàn)象。因此對絲錐進行淬火冷卻過程的數(shù)值模擬,模擬其溫度場和應力場,可以避免產(chǎn)生各種熱處理缺陷。本文通過利用計算機數(shù)值模擬技術(shù),綜合傳熱學理論和熱彈塑性相關知識,采用A nsy s有限元分析軟件,建立了絲錐淬火冷卻過程的三維有限元模型,計算中考慮了材料的熱物性參數(shù)和冷卻介質(zhì)參數(shù)隨溫度的變化,利用熱-力耦合的方法,計算出絲錐淬火冷卻過程的溫度場和應力場,分析了組織場。通過對M1 0×1.5絲錐在油介質(zhì)下淬火冷卻過程進行數(shù)值模擬計算,得出絲錐溫度分布為表面溫度低,心部溫度高;應力場分布為切削刃尖處的等效應力最小,切削刃槽底部的等效應力最大,應力先增大后減小,在1 s左右時等效應力達到最大值3 09 MPa。殘余應力最大處也是出現(xiàn)在螺紋根部,為5.0 6 MPa。對不同尺寸、不同材料的絲錐在不同冷卻介質(zhì)下進行淬火冷卻過程的數(shù)值模擬計算,得出工件尺寸越小,冷卻速度越快,內(nèi)外溫差越小,因此淬火冷卻過程中的應力也越小,殘余應力也越小;不同材料的熱傳導系數(shù)對淬火冷卻過程中的溫度影響較大,熱傳導系數(shù)越大,內(nèi)層熱量向外層傳遞越快,內(nèi)外層溫差越小,使得工件的內(nèi)應力小。因此對于熱傳導系數(shù)大的材料可以采用冷卻速度更快的冷卻介質(zhì);不同冷卻介質(zhì)的對流換熱系數(shù)對淬火冷卻過程中的溫度影響較大,對流換熱系數(shù)越大,工件表面的熱量很快通過介質(zhì)的對流而傳遞到冷卻介質(zhì)中,使工件表面溫度迅速降低,內(nèi)外層溫差大,內(nèi)應力大。
[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.
【學位授予單位】：東北石油大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG162.2
本文編號：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.
【學位授予單位】：東北石油大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TG162.2
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