ABSTRACT
Preventing liquid or gas leaks is one of the most important and most difficult jobs faced by bolted joints. Elevated temperatures can affect the behavior of gasketed joints in several ways, most of them unpleasant. Elevated-temperature creep data are surprisingly rare, considering the importance of creep to joint behavior, plus the fact that many gasketed joints must operate at high service temperatures. A joint leaks when the material being contained escapes through pores or gaps in the gasket, or escapes around the gasket. Many of the proposed asbestos substitute materials fail by thermal degradation; the clays or other inorganics used as binders turn to powder when temperatures are too high. Elevated temperatures can increase the amount of creep or relaxation a gasket experiences under load. The Pressure Vessel Research Committee investigators have sought, and appear to have found, an improved way to define the gasket, to improve the performance of Codedesigned flanges.
