Welding

Intermediate Stress Relieving ISR Heat treating a subassembly in a furnace to a specified cycle after critical constrained weld joint / joints have been completed without allowing the welds to cool below the pre-heat temperature. The rate of heating, soaking temperature, soaking time, and rate of cooling are all affected by the quality and thickness … Read more

Post Weld Heat Treatment PWHT Post Weld Heat Treatment PWHT is a controlled process in which a welded material is reheated to a given temperature, kept at that temperature for a specified amount of time, and then cooled at specific rates to achieve the following objectives….. Stress Relieving This is the stress relief process, which … Read more

Dehydrogenation Heat Treatment (DHT) or Post-heating Dehydrogenation Heat Treatment (DHT) is a treatment utilised specifically when welding or preheat is paused or stopped during the fabrication cycle or PWHT is not done immediately due to further fabrication requirements. It is usually done at 300-350 °C [600 – 650˚F (min 570 ˚F)]. Very common and used … Read more

Preheating Before beginning welding, heat the weldment to a minimum predetermined temperature and maintain it throughout the welding process is called preheating. Preheating is the process of elevating the temperature of the parent material on both sides of the joint to a temperature that is higher than ambient. Preheat is normally required by the relevant … Read more

Heat Treatment of welded joints The intensity of the thermal cycles, which result in large residual stresses and/or weld metal and heat affected zone properties that differ radically from those of the parent material, determines the possibility of a weld defects. Failure might be sudden, occur over a short period of time, or present itself … Read more