Heating Element Failure Investigation

Investigating quality failure in heating elements.

A customer's heating elements were failing in the field. Visual examination by Intertek's metallurgy lab revealed that the more recent components had suffered a greater degree of distortion. The residual stresses revealed that there is a significant amount of tension in the heating element helix produce from manufacturing.

Optical microscopy revealed differences in the microstructures and variance in the amount and location of the precipitates. This variation could have been a consequence of the material overheating to a temperature where re-solution of the precipitates can take place. The lab found clear evidence of distortion and residual stress in the heating element helix, using micrograph data of the failed heating element surface. Evidence of element overheating could be inferred from the relative lack and unevenness of residual stress in contrast to the other elements, indicating stress relief had taken place.

Intertek metallurgy scientists provided concrete recommendations to the customer to assist in resolving the problem. Production component failure investigations are an example of Total Quality Assurance metallurgical related testing services and consultancy offered by Intertek.