G-TECH 308H

The 308H consumables are specifically crafted to match unstabilized 18Cr-10Ni austenitic stainless steels, providing elevated temperature strength and oxidation resistance. Carbon content is controlled within the range of 0.04-0.08%, and weld metal Cr and Ni are kept low to minimize embrittlement by sigma phase. Ferrite is controlled to further mitigate embrittlement, and minor elements and residuals are carefully managed to optimize high-temperature properties. No bismuth-bearing constituents are permitted to ensure compliance with API 582 (<0.002%Bi). Consideration of 308H consumables is advised for welding thick (>12mm) stabilized grades 321H or 347H, preventing in-service HAZ cracking and maintaining creep rupture ductility associated with 347 weld metal. Some authorities recommend type 16-8-2 for these steels, including 304H. Widely used in petrochemical and chemical process plants, especially for fabricating cyclones and transfer lines in catalytic crackers (cat crackers) operating within the range of 400-815°C. No preheat is required, and the maximum interpass temperature is set at 250°C. Post-weld heat treatment (PWHT) is not necessary.