Heat Treatment - PWHT

Heat Treatment – PWHT reduces or redistributes the residual stress introduced by the welding process with a technique that involves heating, soaking and cooling the weldment/machined surface to controlled temperatures. This improves the properties of the surface.

DWI specialises in performing PWHT for the steel and metal fabrication industries including the construction of pressure vessels, pressure piping, storage tanks, buildings, bridges, offshore platforms, power plants, oil and gas refineries, and petrochemical plants.
There is often a mandatory requirement for PWHT due to compliance with welding codes and specifications on certain materials including but not limited to carbon steels, stainless/high alloy steels and work hardened steels. There may also be PWHT requirements based on the wall thickness of the parts being welded together.
Other benefits of PWHT include:

  • 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
DWI can perform PWHT at both our own premises and at our customers’ sites. Our onsite facilities include large furnaces where we can place numerous weldments/machined surfaces for PWHT. Our team of highly skilled and trained PWHT technicians ensures that all surfaces brought in for treatment will meet the specified welding code requirements and be fit for purpose.