针对SS304不锈钢水槽件在拉深过程中出现的零件起皱问题,采用正交试验方法研究凹模圆角半径、压边力和摩擦因数对起皱问题的影响。通过有限元分析软件Dynaform对正交试验方案进行仿真验证,考察了最大增厚率和凹模圆角半径、压边力和摩...针对SS304不锈钢水槽件在拉深过程中出现的零件起皱问题,采用正交试验方法研究凹模圆角半径、压边力和摩擦因数对起皱问题的影响。通过有限元分析软件Dynaform对正交试验方案进行仿真验证,考察了最大增厚率和凹模圆角半径、压边力和摩擦因数等3个成型影响因素之间的关系。试验结果表明,该SS304不锈钢盒型件的最佳成型工艺组合为R1C4F4,即:凹模圆角半径为5 m m,摩擦因数为0.2和压边力为50 kN。依据优化结果,改进了模具结构设计,从而较好地解决了SS304不锈钢盒型件的成型问题。展开更多
The uniaxial time-dependent strain cyclic behaviors and ratcheting of SS304 stainless steel were studied at high temperatures （350 ℃ and 700 ℃）. The effects of straining and stressing rates, holding time at the pe...The uniaxial time-dependent strain cyclic behaviors and ratcheting of SS304 stainless steel were studied at high temperatures （350 ℃ and 700 ℃）. The effects of straining and stressing rates, holding time at the peak and/or valley of each cycle in addition to ambient temperature on the cyclic softening/hardening behavior and ratcheting of the material were discussed. It can be seen from experimental results that the material presents remarkable time dependence at 700 ℃, and the ratcheting strain depends greatly on the stressing rate, holding time and ambient temperature. Some significant conclusions are obtained, which are useful to build a constitutive model describiog the time-dependent cyclic deformation of the material.展开更多
A method to decide near optimal settings of the process parameters in friction welding was proposed.The success of the friction welding process is based on various input parameters like friction pressure,friction time...A method to decide near optimal settings of the process parameters in friction welding was proposed.The success of the friction welding process is based on various input parameters like friction pressure,friction time,upset pressure and upset time and output parameters like tensile strength,hardness and material loss.Ti-6Al-4V and SS304L(SS) materials were joined by friction welding process using interlayer techniques.The Box-Behnken design and response surface methodology(RSM) were applied to deciding the number of experiments to be performed and identify the optimum process parameters for obtaining better joint strength.The results were highly encouraging.Join strength of 523 MPa was obtained at a friction pressure of 12 N/mm^2,upset pressure of40 N/mm^2,friction time of 1.2 s and upset time of 7 s.展开更多
Based on the time-dependent strain cyclic characteristics and fatigue behaviors of SS304 stainless steel under multi-axial cyclic loading at 700 ？ C, and in the frame of unified visoco-plastic cyclic constitutive mod...Based on the time-dependent strain cyclic characteristics and fatigue behaviors of SS304 stainless steel under multi-axial cyclic loading at 700 ？ C, and in the frame of unified visoco-plastic cyclic constitutive model and continuum damage mechanics theory, the damage-coupled multi-axial time-dependent constitutive model and fatigue failure model were proposed. In the model, the evolution equation of damage was introduced in and the time-dependent effects, e.g. holding time, loading rate, were taken into account. The model was applied to the simulation of whole-life cyclic deformation behaviors and prediction of LCF life for SS304 stainless steel in multiaxial time-dependent low cycle fatigue tests. It is shown that the simulated results agree well with experimental ones.展开更多
SS304 is a commercial grade stainless steel which is used for various engineering applications like shafts, guides, jigs, fixtures, etc. Ceramic coating of the wear areas of such parts is a regular practice which sign...SS304 is a commercial grade stainless steel which is used for various engineering applications like shafts, guides, jigs, fixtures, etc. Ceramic coating of the wear areas of such parts is a regular practice which significantly enhances the Mean Time Between Failure (MTBF). The final coating quality depends mainly on the coating thickness, surface roughness and hardness which ultimately decides the life. This paper presents an experimental study to effectively optimize the Atmospheric Plasma Spray (APS) process input parameters of Al<sub>2</sub>O<sub>3</sub>-40% TiO2 ceramic coatings to get the best quality of coating on commercial SS304 substrate. The experiments are conducted with a three-level L<sub>18</sub> Orthogonal Array (OA) Design of Experiments (DoE). Critical input parameters considered are: spray nozzle distance, substrate rotating speed, current of the arc, carrier gas flow and coating powder flow rate. The surface roughness, coating thickness and hardness are considered as the output parameters. Mathematical models are generated using regression analysis for individual output parameters. The Analytic Hierarchy Process (AHP) method is applied to generate weights for the individual objective functions and a combined objective function is generated. An advanced optimization method, Teaching-Learning-Based Optimization algorithm (TLBO), is applied to the combined objective function to optimize the values of input parameters to get the best output parameters and confirmation tests are conducted based on that. The significant effects of spray parameters on surface roughness, coating thickness and coating hardness are studied in detail.展开更多
文摘针对SS304不锈钢水槽件在拉深过程中出现的零件起皱问题,采用正交试验方法研究凹模圆角半径、压边力和摩擦因数对起皱问题的影响。通过有限元分析软件Dynaform对正交试验方案进行仿真验证,考察了最大增厚率和凹模圆角半径、压边力和摩擦因数等3个成型影响因素之间的关系。试验结果表明,该SS304不锈钢盒型件的最佳成型工艺组合为R1C4F4,即:凹模圆角半径为5 m m,摩擦因数为0.2和压边力为50 kN。依据优化结果,改进了模具结构设计,从而较好地解决了SS304不锈钢盒型件的成型问题。
基金Item Sponsored by National Natural Science Foundation of China (NSFC10402037) Theoretical Research Fund of SouthwestJiaotong University (2005XJB23)
文摘The uniaxial time-dependent strain cyclic behaviors and ratcheting of SS304 stainless steel were studied at high temperatures （350 ℃ and 700 ℃）. The effects of straining and stressing rates, holding time at the peak and/or valley of each cycle in addition to ambient temperature on the cyclic softening/hardening behavior and ratcheting of the material were discussed. It can be seen from experimental results that the material presents remarkable time dependence at 700 ℃, and the ratcheting strain depends greatly on the stressing rate, holding time and ambient temperature. Some significant conclusions are obtained, which are useful to build a constitutive model describiog the time-dependent cyclic deformation of the material.
文摘A method to decide near optimal settings of the process parameters in friction welding was proposed.The success of the friction welding process is based on various input parameters like friction pressure,friction time,upset pressure and upset time and output parameters like tensile strength,hardness and material loss.Ti-6Al-4V and SS304L(SS) materials were joined by friction welding process using interlayer techniques.The Box-Behnken design and response surface methodology(RSM) were applied to deciding the number of experiments to be performed and identify the optimum process parameters for obtaining better joint strength.The results were highly encouraging.Join strength of 523 MPa was obtained at a friction pressure of 12 N/mm^2,upset pressure of40 N/mm^2,friction time of 1.2 s and upset time of 7 s.
基金supported by the Fundamental Research Funds for the Central Universities (No.SWJTU09ZT35)National Science Fund for Distinguished Young Scholars of China (No.11025210)
文摘Based on the time-dependent strain cyclic characteristics and fatigue behaviors of SS304 stainless steel under multi-axial cyclic loading at 700 ？ C, and in the frame of unified visoco-plastic cyclic constitutive model and continuum damage mechanics theory, the damage-coupled multi-axial time-dependent constitutive model and fatigue failure model were proposed. In the model, the evolution equation of damage was introduced in and the time-dependent effects, e.g. holding time, loading rate, were taken into account. The model was applied to the simulation of whole-life cyclic deformation behaviors and prediction of LCF life for SS304 stainless steel in multiaxial time-dependent low cycle fatigue tests. It is shown that the simulated results agree well with experimental ones.
文摘SS304 is a commercial grade stainless steel which is used for various engineering applications like shafts, guides, jigs, fixtures, etc. Ceramic coating of the wear areas of such parts is a regular practice which significantly enhances the Mean Time Between Failure (MTBF). The final coating quality depends mainly on the coating thickness, surface roughness and hardness which ultimately decides the life. This paper presents an experimental study to effectively optimize the Atmospheric Plasma Spray (APS) process input parameters of Al<sub>2</sub>O<sub>3</sub>-40% TiO2 ceramic coatings to get the best quality of coating on commercial SS304 substrate. The experiments are conducted with a three-level L<sub>18</sub> Orthogonal Array (OA) Design of Experiments (DoE). Critical input parameters considered are: spray nozzle distance, substrate rotating speed, current of the arc, carrier gas flow and coating powder flow rate. The surface roughness, coating thickness and hardness are considered as the output parameters. Mathematical models are generated using regression analysis for individual output parameters. The Analytic Hierarchy Process (AHP) method is applied to generate weights for the individual objective functions and a combined objective function is generated. An advanced optimization method, Teaching-Learning-Based Optimization algorithm (TLBO), is applied to the combined objective function to optimize the values of input parameters to get the best output parameters and confirmation tests are conducted based on that. The significant effects of spray parameters on surface roughness, coating thickness and coating hardness are studied in detail.
