Welded Metal Bellow

An Edge Welded Bellows is manufactured by edge welding a series of diaphragms together using a highly controlled and very precise Micro TIG or Plasma welding process.
No material is added during the fusion process and the resultant welds beads have a bright appearance and are very uniform in shape.
It is by measuring the shape, or geometry, of the welds that the quality and consistency of this specialised welding process is determined and controlled.
The diaphragms are perhaps described as crinkly washers but are in fact precision pierced and blanked components having inside and outside diameters with a rippled profile formed in the surface.
Usually very thin materials are used in the production of the diaphragms, typically 0.05 mm to 0.25 mm thick in Stainless Steel, but often in more exotic alloys like Monel, Hastelloy, Inconel, Titanium etc.
It is usual to have a so-called Male and Female form to the diaphragms ensuring the completed bellows fully nests without the diaphragms interfering.
The solid length of a welded bellows not much more than the total thickness of all the diaphragms used in the bellows plus a small design allowance.
The Male and Female diaphragms are first welded together at their inside diameters to form a welded pair or convolution. The convolutions are then welded together at their outside diameters to form the Bellows. By leak checking the finished Bellows on a Mass Spectrometer and taking weld samples during production it is possible to produce a bellows with high integrity welds equal to the most demanding applications.