1. How to select materials for waterwall service?
Carbon steel (SA210): Standard choice
Low alloy (T11/T22): Higher strength needed
Co-extruded: Corrosion resistant liner
Clad options: Stainless overlay
Coated: Thermal spray protection
2. What alloys for superheater/reheater tubes?
| Material | Max Temp (°C) | Key Features |
|---|---|---|
| T22 | 565 | Economical |
| T91 | 625 | High strength |
| TP304H | 760 | Oxidation resistant |
| TP347H | 760 | Creep resistant |
| Alloy 617 | 950 | Advanced USC |
3. How does temperature affect material choice?
<450°C: Carbon steel sufficient
450-550°C: Low alloy steels
550-650°C: High alloy steels
650-750°C: Austenitic stainless
>750°C: Nickel-based superalloys
4. What are cost vs. performance tradeoffs?
Carbon steel: Low cost, limited capability
Low alloy: Moderate cost, better performance
Stainless: Higher cost, corrosion resistance
Nickel alloys: Premium cost, extreme service
Coatings: Added cost, extend base material life
5. What are emerging material technologies?
ODS alloys: Oxide dispersion strengthened
HEAs: High entropy alloys
Nano-structured: Enhanced properties
Composites: Hybrid material systems
AM materials: Custom compositions
