Power Generation
RAS Alloy supplies high-temperature nickel alloys for gas turbine hot-section components, ultra-supercritical boiler tubing and industrial power plant hardware. Materials are certified to ASME Boiler & Pressure Vessel Code for long-term elevated temperature service.
Typical Alloy Grades
617 / 625 / 718 / X-750 / Nimonic 80A
Ultra-supercritical boiler tubes and headers
Inconel 617, Inconel 740H
Gas turbine transition ducts and liners
Hastelloy X, Nimonic 75
Steam turbine fasteners and bolting
Inconel X-750, Nimonic 80A
Waste-to-energy incinerator components
Inconel 625, Inconel 601
Heat recovery steam generator tubing
Incoloy 800H, Inconel 625
Applicable Standards
Supercritical Boiler Tube Weld Cracking — Inconel 617
A 700°C ultra-supercritical demonstration plant experienced circumferential cracking in IN617 boiler tube butt welds after 8,000 hours of service at 710°C/30 MPa steam conditions.
The weld filler metal (ERNiCrCoMo-1) had lower aluminum content than the base metal, resulting in insufficient gamma-prime strengthening in the weld zone. Creep void formation concentrated at the weld fusion line where hardness dropped from 220 HV (base) to 175 HV (weld).
RAS Alloy now supplies IN617 with matching composition filler (ERNiCrCoMo-1A) and post-weld solution treatment at 1175°C for 30 minutes. Weld procedure qualification includes cross-weld creep testing at 750°C/100 MPa with minimum 500-hour rupture life.