The Sensitisation Behaviour of Alloy UNS N08825 After Heat Treatment as Used in Clad Materials

摘要

Alloy UNS N08825 is widely used in sour service environments of the oil and gas industry. In case of large vessels alloy UNS N08825 is often explosion clad to carbon steel and needs to undergo the same heat treatment requirements as the substrate material. Where post weld heat treatment (PWHT) procedures are required by the Code the behaviour of the clad material has to be considered and standard corrosion tests are frequently used to monitor it. Most common PWHT procedures require intermediate temperatures in the range of 600-650 °C (1112 - 1202 F). It is well known that depending on the time of heat treatment at these temperatures nickel alloys may undergo microstructural changes that influence the result of the standard corrosion tests. The aim of this paper is to present recent standard test corrosion data obtained in laboratory for alloy UNS N08825 after PWHT in comparison with as delivered (soft annealed) material.