Assembling tubes on tube sheets
Stainless steel metal work

Figure 6 describes this type of fastening, which must ensure both mechanical strength and tightness. According to current European regulations (Pressure Equipment Directive – DESP 97/23CE), this type of assembly, described as "permanent", must be the subject of an operating mode qualification.

The operation consists in plastically deforming the tube, either by :

• mechanical chucking (action of rollers on a tapered shank) ;

• hydraulic expansion ;

• explosive charge (for very specific cases).

The outer edge of the tube need not be flared, which has no effect on the subsequent behaviour of the assembly. The use of flaring grooves is...