Failure mechanisms in metal-sheathed thermocouples

This paper addresses industrial use of metal sheathed thermocouples and does not consider sophisticated, one of a kind research or test performance applications. Failures can result because of shortcomings in design, fabrication, installation, operation, and maintenance. These observations are based on personal laboratory and field experience and on information from several suppliers and users. Investigating the failure mechanisms of metal sheathed thermocouples is important because if we can reduce the failure rate, we can reduce product cost, and improve quality while becoming more efficient and cost effective. Failure mechanisms can be grouped according to the primary cause of failure; mechanical, chemical, electrical, and thermal.