JR FURNACE offers Post Weld Heat Treatment to retain material strength of the part after welding. By PWHT, one can control the hardness of the material and reduce the residual stress induced. Hence, after welding, one has to process the material through Post Weld Heat Treatment.PWHT avoids Weld failures, susceptible brittle fracture and high cracking potential.
Post Weld Heat Treatment is carried out in Bogie Hearth Furnace and Chamber Furnace. Most common types of Post Weld Heat Treatment are Post Heating & Stress Relieving.
Hydrogen induced cracking is the common occurrence during welding. This is due to high levels of hydrogen diffuse into the material. The material after welding permeates hydrogen from the welded area. This PWHT process should start after welding and maintain a hot temperature for a couple of hours. The temperature is based on the thickness and type of material used.
Once the welding process is complete, the material has an enormous amount of residual stress. This leads to stress corrosion and hydrogen induced cracking. Hence, PWHT releases these stresses and cracks. The temperature is set to change as and when required.