Alloy 347 (UNS S34700) is a columbium stabilized austenitic stainless steel with good general corrosion resistance and somewhat better resistance in strong oxidizing conditions than 321 (UNS S32100). It has excellent resistance to intergranular corrosion after exposure to temperatures in the chromium carbide precipitation range of 800 - 1500°F (427 - 816°C). The alloy has good oxidation resistance and creep strength to 1500°F (816°C). It also possesses good low temperature toughness.

Alloy 347H (UNS S3409) is the higher carbon (0.04 - 0.10) version of the alloy. It was developed for enhanced creep resistance and for higher strength at temperatures above 1000°F (537°C). In most instances, the carbon content of the plate enables dual certification.

Alloy 347 cannot be hardened by heat treatment, only by cold working. It can be easily welded and processed by standard shop fabrication practices.

Applications

• Chemical Processing

• Food Processing - equipment and storage

• Petroleum Refining - fluid catalytic cracking units, polythionic acid service

• Waste Heat Recovery - recuperators