Stainless steel spring gasket swelling problem

  In the assembly process of spring washer, the spring washer directly enlarges and expands outward, which is called rising ring.  This phenomenon has a long history, the cause of which was reported half a century ago, but so far there are different opinions, there is no clear conclusion.  According to the fifth phase of the 2000 aerospace standardization on the "spring rise ring causes of primary discussion" in the discussion also do a detailed explanation, its main is:  Ball pad as the rotation of the nut is pressing, in this process, the ball pad stress increases gradually, pressure usually achieve half the elasticity test load, to continue to pressure nut until the axial pre-tightening force in the elasticity of the spring washer test load value, to put pressure on nut, nut can produce a radial outward to play mat of friction,  This is very easy to lead to the spring due to the radial outward friction caused by outward expansion resulting in the phenomenon of rising ring, this problem is relatively difficult to solve.