TAPPI TIP0402-11 PDF

This Technical Information Paper (TIP) covers liquid penetrant testing of new suction roll shells produced for new or replacement equipment. This TIP is specifically intended for centrifugally cast shells, but may be adapted for testing rolled and welded or forged suction roll shells.

It is recognized that no suction roll shell is perfect and shells can deteriorate under widely different applications and operating conditions. Therefore, the purpose of this TIP is to establish procedures for documenting the surface condition of the suction roll shell, as manufactured, so that the information may be compared with data gathered periodically after the shell is in service. The procedure will normally be used for stainless steel shells, but may be used for bronze shells.

It is beyond the scope of this TIP to recommend criteria for rejection of new shells based on the size or quantity of flaws. However, manufacturers will usually have standards for acceptance/rejection of shells that they produce.