G-TECH 308H

308H consumables are specifically designed for applications involving unstabilized 18Cr-10Ni austenitic stainless steels, offering high resistance to elevated temperatures and oxidation. These steels and weld metal have a carefully controlled carbon content between 0.04% and 0.08%. The levels of chromium (Cr) and nickel (Ni) in the weld metal are kept low, and the ferrite is regulated to minimize brittleness due to sigma phase formation. Minor elements and impurities, both beneficial and harmful, are controlled to optimize high-temperature properties. It is crucial that these consumables exclude components containing bismuth, ensuring a Bi level below 0.002% as required by API 582 standards. 308H consumables are also recommended for welding stabilized grades 321H or 347H thicker than 12 mm, preventing cracking in the heat-affected zone (HAZ) and low ductile fracture resistance to creep when using 347 weld metal. It is important to note that some standards suggest the use of 16-8-2 type alloys for these steels, including 304H. 308H is widely used in petrochemical and chemical processing plants, particularly in the construction of cyclones and transfer lines used to recirculate the catalyst in catalytic crackers (cat crackers) operating between 400 °C and 815 °C. Preheat is not required; the maximum interpass temperature is 250 °C. No post-weld heat treatment (PWHT) is required.