Carefully controlled PWHT is a crucial step in maximizing the life of your process equipment. PWHT tempers the metal and reduces tensile stresses, minimizing the risk of brittle fracture, stress, corrosion cracking and metal fatigue. This is especially important for equipment used in harsh service environments.
The traditional low-voltage Electrical Resistance method of heat treatment uses ceramic blankets stepped down to 80 volts to provide a quick and convenient approach to many jobs, particularly preheat and Post-weld Heat Treatment (PWHT).
Advanced automated systems control and document welding preheat to reduce thermal stress in two primary ways. First, it drives off moisture that would release hydrogen that could penetrate the steel and cause porosity and subsequent cracking. Second, it reduces heat loss to the surrounding metal, minimizing the rate of weld hardening and allowing hydrogen that is present to escape.
With the introduction of Induction Heat System, this simple and cost-effective heating process can be applied in the following applications to deliver fast and consistent heat:
Applications that would typically require hours to heat can be done in minutes utilizing induction heating. Discover the dramatic benefits of using induction compared to current processes by using the calculators for time-to-temperature for typical heating applications of pipe and plate.
Pre-heating of pipe before welding on a transmission pipeline. Air-cooled induction blankets are perfect for this application. The induction coil is sewn into a durable 3-D woven silica material with preheat insulation on the bottom. The entire blanket can be moved from joint-to-joint with minimal change over time. Induction blankets can be used to heat the target material up to 400° F.