基于ANSYS激光淬火 外文.pdf

Study on numerical simulation of laser quenching based on ANSYS Jianlai Wang1 a Jian Cao1 b Qiankai Lin1 c Hui Feng1 d and Haihua Shen1 e 1 Department of Mechanical and Electrical Jiaxing University Jiaxing 314001 China afhcanyue bcaoj 2005 c1120643462 d1012291313 e80616150 Keywords ANSYS temperature field laser quenching numerical simulation Abstract In this paper a temperature field model of 45 steel shafts during the laser quenching was built and simulated by using ANSYS software Its surface temperature distribution of the shaft during the laser beams scanning was simulated Their effects of different laser power laser beams spot size and scan speed on part s quenching performance were analyzed Introduction Laser quenching is refereed to use laser beams scanning the parts in heat treatment position so that the scanned area is warmed up quickly and cooled in the air Its principle of laser quenching is the same as the ordinary heat treatment Its advantages are that the laser as a heat source heat the metal in a very short time and its processing area is also very small The surface temperature and thermal penetration depth is proportional to the square of the laser irradiation time when the laser beams scan the metal surface Therefore the appropriate adjustment of the laser beams spot size scanning speed and laser power could control the metal surface temperature and heat penetration depth ANSYS software could be used to calculate the temperature distribution and other thermal physical parameters such as thermal gradient and heat flux density of a system or component Thermal analysis modes ANSYS software provides includes heat conduction heat convection and heat radiation This paper use the ANSYS software to simulate the instantaneous surface temperature field of 45 steel shaft in order to obtain the most suitable scanning speed laser beams spot size and laser power when part is scanned by the laser beams Basic theory of laser surface quenching In the laser quenching process a part of the energy irradiation is reflected by the metal surface and the other is absorbed by the metal surface The energy transfer between laser photon and the metal material is actually the process that metal material absorbs laser photon and is heated Therefore temperature field simulation research on laser surface quenching process is based on the theory basis of heat conduction differential equation Considering the phase transition process and the varied thermal physical coefficient the heat transfer partial differential formula could be expressed as followers TTTT C txxyyzz 1 In Eq 1 c and are respectively density heat capacity and thermal conductivity of material When the parts surface is quenched by using the laser beams heat convection is formed to dissipate the heat quantity so the boundary conditions are the third class of boundary conditions the boundary conditions as shown in the following formula 1 Sf T tt n 2 In Eq 2 and are respectively the surface heat transfer coefficient and heat transfer boundary of parts S t is the surface temperature of parts and f t is its temperature of quenching medium Advanced Materials Research Vols 538 541 2012 pp 1862 1865 Online available since 2012 Jun 14 at 2012 Trans Tech Publications Switzerland doi 10 4028 All rights reserved No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of TTP ID 111 2 225 48 18 12 12 02 44 50 Numerical simulation of temperature field for 45 steel shaft laser quenching In this paper a three dimension model of 45 steel shaft is built by ANSYS software which is shown in Fig 1 Thermal analysis is done by using 3D thermal solid SOLID70 Relationship among specific heat capacity thermal conductivity and temperature for 45 steel are shown in Table 1 And relationship between convection heat transfer coefficient and temperature are shown in table 2 Table 1 Relationship among specific heat capacity thermal conductivity and temperature for 45 steel Table 2 Relationship between convection heat transfer coefficient c h and temperature T for 45 steel CT 50 100 200 300 350 400 12 CmWhc 2000 3800 6000 13500 14000 12500 CT 500 600 700 800 850 12 CmWhc 7000 4200 1500 500 300 Simulation result analysis of laser quenching Taking the environment temperature is 20 and considering the heat flux density would be applied into parts quenching surface during simulation The heat flux density is often refereed to the power density F the material surface absorber p F A 3 In Eq 3 is the absorption rate The absorption rate is set to 40 in this paper p is the laser power and A is the laser beams spot area Table 3 The heat flux density under different laser beams spot diameter and laser power It is appropriate to change the power density in order to simulate the laser quenching process under different laser beams spot diameter and laser power Heat flux density Table 3 provides would be loaded and taking the time step is 1s T C 20 100 200 300 400 500 CkgJCP 472 480 498 524 560 615 CmW 47 7 43 5 40 4 38 1 36 0 34 16 T C 600 700 755 800 900 1000 CkgJCP 700 854 1064 806 637 602 CmW 31 98 28 66 25 14 26 49 25 92 24 02 laser power w laser beams spot diameter mm heat flux density w m2 800 6 11317694 1000 4 31831015 1000 6 14147117 1000 8 7957754 1200 6 16976540 Fig 1 45 steel shaft three dimensional solid model Advanced Materials Research Vols 538 5411863 Fig 4 Temperature field distribution of 45 steel shaft when the scan time is 6s Fig 5 Temperature field distribution of 45 steel shaft when the laser power is 800w Fig 6 Temperature field distribution of 45 steel shaft when the laser power is 1000w Fig 3 Temperature field distribution of 45 steel shaft when the scan time is 5s Fig 7 Temperature field distribution of 45 steel shaft when the laser power is 1200w Fig 2 Temperature field distribution of 45 steel shaft when the scan time is 4s Fig 8 Temperature field distribution of 45 steel shaft when the laser beams spot diameter is 4mm Fig 9 Temperature field distribution of 45 steel shaft when the laser beams spot diameter is 5mm 1864Materials Processing Technology II Fig 2 Fig 3 and Fig 4 respectively show the numerical simulation results of 45 steel shaft s temperature field under different scan speeds when the laser power is 800w and the laser beams spot diameter is 6mm Based on the above simulation results it could be seen that its surface temperature of 45 steel shaft is changed with the laser beams moves When the heating time is longer and the scan time is slower its peak temperature of shafts surface would be higher Fig 5 Fig 6 and Fig 7 respectively show the 45 steel shaft s temperature field distribution under 800w 1000w and 1200w laser power when the scan time is 6s and the laser beams spot diameter is 6mm It could be seen that its surface temperature of 45 steel shaft would be changed with the laser power The bigger laser power is the higher shaft s surface temperature is The reason is that the bigger laser power is the radiation laser energy of shaft surface in unit time is more and the higher its temperature is Fig 8 Fig 9 and Fig 10 show 45 steel shaft s temperature field under different laser beams spot diameter when the laser power is 1000w and the scan time is5s and changed The numerical simulation results show that 45 steel shaft s surface temperature is changed with the laser beams spot diameter The smaller the laser beams spot diameter is the higher the shaft s surface temperature is Conclusion In this paper ANSYS software was used to simulate its surface temperature distribution of 45 steel shaft during the laser beams scanning It could be seen from the numerical results that laser power laser beams spot diameter and scan speed all have an effect on the temperature field Therefore it could also provide a theory basis of analyzing the phase transformation hardening process and its principle of laser quenching technology Acknowledgements This work was financially supported by the Jiaxing science and technology project 2009AY1001 Author Biography Jian Cao was born in Shangyu City Zhejiang Province China in 1969 He received Master s Degree from Zhejiang University Now he is a profess