Abstract:The sealing performance of welded metal bellows is affected by its balance diameter,while the balance diameter is related to the structural parameters of the bellows.In order to study the influence law and influence degree of each structural parameter on the balance diameter and evaluate the seal safety conveniently,the mathematical model and threedimensional model of the welded metal bellows was established.According to the mathematical model,the balance diameter expression of the welded metal bellows under ideal conditions was obtained.By changing form of convolution,thickness of convolution,number of convolution and pitch of convolution in the ANSYS workbench,the balance diameter values under the corresponding parameters were obtained,and the influence of different parameters on the balance diameter was analyzed.The analysis results show that when other parameters remain unchanged,the equilibrium diameter of welded metal bellows with different form of convolution under the action of internal and external pressures is increased rapidly first with the increase of pressure,and then the increasing trend is gradually decreased.Under the action of internal pressure condition,the balance diameter of the bellows is decreased with the increase of the thickness of convolution,increased with the increase of the number of convolution,and decreased with the increase of the pitch of convolution.Under the external pressure condition,the balance diameter is decreased with the increase of the thickness of convolution,increased with the increase of the number of convolution,and increased with the increase of the pitch of convolution.Under the external pressure condition,the influence degree of each structural parameter on the balance diameter of the bellows is in the order of the thickness of convolution,the pitch of convolution,the number of convolution and the form of convolution.Under the external pressure condition,the influence degree of each structural parameter on the balance diameter of the bellows is in the order of the thickness of convolution,the form of convolution,the pitch of convolution and the number of convolution.