### 1. Material of A213 T12
**SA213 T12** is a **Chromium-Molybdenum alloy steel** for high-temperature service. It is standardized under ASTM A213/A213M as **Grade T12**.
---
### 2. SA213 Material
**SA213 (ASTM A213/A213M)** is a specification for **seamless ferritic and austenitic alloy-steel boiler, superheater, and heat-exchanger tubes**. It covers grades like T2, T5, T9, T11, T12, T22, T91, TP304, etc., used in high-pressure/temperature environments.
---
### 3. Composition of SA213 T9
**SA213 T9** composition (ASTM A213/A213M):
- **Carbon (C)**: 0.15% max
- **Manganese (Mn)**: 0.30–0.60%
- **Phosphorus (P)**: 0.025% max
- **Sulfur (S)**: 0.025% max
- **Silicon (Si)**: 0.25–1.00%
- **Chromium (Cr)**: 8.00–10.00%
- **Molybdenum (Mo)**: 0.90–1.10%
*UNS Designation: K90941*
---
### 4. SA 210 Material
**SA210 (ASME SA210/ASTM A210)** covers **seamless medium-carbon steel boiler and superheater tubes**. Key grades:
- **Grade A1**: Carbon steel (Mn 0.27–0.93%)
- **Grade C**: Higher-strength carbon steel (Mn 0.29–1.06%)
*Commonly used in low/medium-temperature boiler sections.*
---
### 5. Hardness of SA213 T91
**SA213 T91** hardness (ASTM A213/A213M):
- **After Normalizing & Tempering**:
- **Maximum Hardness**: 265 HBW (Brinell) or 25 HRC (Rockwell C)
- **Typical Range**: 190–250 HBW
*Controlled hardness ensures creep strength and weldability for high-temperature service (up to 600°C).*
For all materials, refer to the latest ASTM/ASME specifications for certified testing and tolerances.
