increased with the increase of temperature difference,the minimum fatigue life is decreased with the increase of temperature difference.The mechanical and fatigue properties of Vtype metal bellows are better than those of Utype metal bellows.The stress end is the most easily damaged part of the whole metal bellows,where the deformation and stress are the largest and the fatigue life value is the smallest,so the strengthening treatment should be carried out to improve the service life and operation stability of the metal bellows.