1. **What is SA213 gr T22 material?**
SA213 T22 is a **chromium-molybdenum alloy steel** tubing material specified in ASME SA213 standard. It contains approximately **2.25% chromium and 1% molybdenum**. It is used for high-temperature applications like boiler superheaters, heat exchangers, and pressure vessels due to its good creep strength and oxidation resistance up to ~600°C (1112°F).
2. **What is A213?**
**A213 (or SA213)** is an ASTM/ASME standard titled "*Standard Specification for Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes*". It covers seamless stainless and alloy steel tubes designed for high-temperature service in boilers, superheaters, and heat exchangers. Grades include T5, T9, T11, T12, T22, T91, TP304, etc.
3. **What is SA210 gr A1 material?**
SA210 A1 is a **carbon steel** tubing material per ASME SA210 standard. It is a **minimum-specified carbon manganese steel** used in boiler and superheater applications at moderate temperatures. It offers good weldability and formability but lower high-temperature strength compared to alloy steels like T22/T91.
4. **What is the temperature range for SA213 T91?**
SA213 T91 is typically used in the temperature range of **566°C to 650°C (1050°F to 1202°F)** for long-term service. Below 566°C, it may be susceptible to **temper embrittlement**, requiring careful thermal treatment. The maximum design temperature is generally capped at **650°C (1202°F)**.
5. **What is T91 steel grade?**
T91 (Grade 91) is a **high-strength chromium-molybdenum-vanadium alloy steel** with **9% chromium**. It is normalized-and-tempered to form a **tempered martensitic microstructure**. Key properties include:
- Excellent creep strength at 600–650°C
- Oxidation/corrosion resistance
- Used in power plants for superheater/reheater tubes, headers, and piping.
- Composition: 8.0–9.5% Cr, 0.85–1.05% Mo, 0.18–0.25% V, +Nb/N.
### Key Standards Summary:
| Standard | Purpose | Common Grades |
|----------|---------|--------------|
| **SA213/A213** | Alloy/stainless steel boiler tubes | T22, T91, TP304H |
| **SA210** | Carbon steel boiler tubes | A1, C |
For T91, always verify heat treatment (normalized at 1040–1080°C + tempered at 730–780°C) to ensure properties.
