Why is post-weld heat treatment (PWHT) inspection needed?
Post-Weld Heat Treatment (PWHT) inspection is carried out to ensure that welded components have achieved the required mechanical properties and structural integrity after the heat treatment process.
In many industrial applications in India—such as pressure vessels, pipelines, boilers, power plants, and heavy fabrication—welding can introduce residual stresses and hardness variations in the material. PWHT helps reduce these stresses, improve ductility, and enhance the overall performance and life of the weld joint.
PWHT inspection is needed to verify that the heat treatment process has been performed correctly as per the specified temperature, holding time, and cooling cycle. It also ensures that the weld and heat-affected zone meet the required hardness limits and material property standards.
In the Indian context, PWHT is commonly governed by standards such as ASME Section VIII, ASME B31.3, Indian Standards (IS), and project-specific specifications.
At Uniquo, we conduct PWHT inspection and verification to ensure compliance with applicable codes, helping industries maintain safety, prevent weld failures, and ensure long-term reliability of critical equipment and structures.