Heat Treatment & PWHT

Controlled heating of the joint area before and during welding to reduce the risk of hydrogen cracking and to manage thermal gradients.

Working Principle

Electrical resistance heating elements or gas systems raise the component to the specified pre-heat temperature, monitored by attached thermocouples.

Applications

• Carbon and low alloy steel welding
• Heavy wall piping and vessels
• Field repair welding

Equipment

Resistance heating units, ceramic pad heaters, insulation and calibrated temperature control equipment.

Reporting

Temperature records confirming pre-heat maintenance throughout welding.

Controlled thermal cycle applied after welding to reduce residual stress and improve the metallurgical condition of the weld and heat-affected zone.

Working Principle

The component is heated at a controlled ramp rate to the soak temperature, held for the specified duration, and cooled at a controlled rate as defined by the applicable procedure.

Applications

• Pressure vessel and piping welds
• Code-required stress relief
• Repair welds requiring PWHT

Equipment

Programmable heat treatment consoles, ceramic pad heaters, thermocouples and chart or digital recorders.

Reporting

Time-temperature charts, thermocouple layout records and procedure references.

Soak temperature, ramp rates and hold time follow the applicable code and approved procedure for the material and thickness.

Thermal treatment to relieve fabrication and welding stresses, with controlled cooling to avoid reintroducing stress or undesirable microstructure.

Working Principle

Uniform heating and cooling across the treated zone, managed through zone control and thermocouple feedback.

Applications

• Fabricated assemblies
• Machined and welded components
• Repair scopes requiring stress relief

Equipment

Multi-zone heat treatment consoles with insulation and monitoring.

Reporting

Recorded thermal cycle with deviation notes where applicable.