Post Weld Heat Treatment (PWHT)


Postweld heat treatment (PWHT), or stress relief as it is sometimes known, is a method for reducing and redistributing the residual stresses in the material that have been introduced by welding. In addition to reduction and redistribution of residual stresses, PWHT at higher temperatures permits some tempering, precipitation or ageing effects to occur. These metallurgical changes can reduce the hardness of the as-welded structure, improving ductility and reducing the risks of brittle fracture. In some steels, however, ageing/precipitation processes can cause deterioration in the mechanical properties of the steel, in which case, specialist advice should be taken on the appropriate times and temperatures to use.


Our Solution:

AlphaNDT’s PWHT team of highly skilled and trained PWHT technicians ensures that all weldments/machined surfaces brought in for treatment will meet the specified welding code requirements and be fit for purpose.

AlphaNDT can also provide the stress relief service for big component by Meta-Lax Vibration Method.



  • Improved ductility of the material
  • Improved or reduced hardness
  • Reduced risk of brittle fracture
  • Relaxed thermal stress
  • Tempered metal
  • Removal of diffusible hydrogen (to prevent hydrogen induced cracking)
  • Improved metallurgical structure
  • Reduce the risk of company liability with documented safety standards
  • AlphaNDT´s exclusive, one-stop shop services.