Hastelloy B-2 is engineered for one job — exceptional resistance to pure hydrochloric acid. Hastelloy C-276 is the all-rounder for mixed and oxidizing/reducing acid environments. Choosing wrong can be costly. Here is the comparison.
1. Chemical Composition Comparison (%)
| Element | Hastelloy B-2 (UNS N10665) | Hastelloy C-276 (UNS N10276) |
|---|---|---|
| Nickel (Ni) | Balance | Balance |
| Molybdenum (Mo) | 26.0 – 30.0 | 15.0 – 17.0 |
| Chromium (Cr) | ≤1.0 | 14.5 – 16.5 |
| Iron (Fe) | ≤2.0 | 4.0 – 7.0 |
| Tungsten (W) | — | 3.0 – 4.5 |
| Cobalt (Co) | ≤1.0 | ≤2.5 |
| Carbon (C) | ≤0.01 | ≤0.01 |
2. Mechanical Properties (Typical, Annealed)
| Property | Hastelloy B-2 | Hastelloy C-276 |
|---|---|---|
| Tensile Strength (MPa) | ≥760 | ≥690 |
| Yield Strength 0.2% (MPa) | ≥350 | ≥283 |
| Elongation (%) | ≥40 | ≥40 |
| Hardness | ≤100 HRB | ≤100 HRB |
3. Key Technical Differences
- Corrosion niche: B-2 excels in pure, non-oxidizing hydrochloric and sulfuric acids; C-276 handles mixed, oxidizing, and chlorinated media.
- Chromium: C-276's 15% Cr gives broad oxidizing-acid resistance that B-2 lacks.
- Weldability: Both are weldable, but B-2 is extremely sensitive to impurity pickup during welding.
- Cost & availability: C-276 is far more common and readily stocked; B-2 is a specialty alloy.
5. Key Application Areas
Hastelloy B-2 application areas
- Pure hydrochloric acid handling and storage
- Reducing sulfuric acid processes
- Chemical reactors and heat exchangers in strongly reducing service
- Halogenation and organic chlorination equipment
Hastelloy C-276 application areas
- Flue gas desulfurization (FGD) systems
- Mixed acid and oxidizing chemical processing
- Seawater and brine handling equipment
- Pulp and paper bleaching systems
Frequently asked questions
When should I choose B-2 over C-276?
For pure hydrochloric acid or strongly reducing sulfuric acid service where oxidizing agents are absent.
Can C-276 handle hydrochloric acid?
Yes, but in concentrated, hot, oxidizing HCl, B-2 or a more specialized alloy may perform better.
Why is B-2 so chromium-poor?
High Cr improves oxidizing-acid resistance but worsens performance in strongly reducing acids — a deliberate trade-off.
Is B-2 weldable?
Yes, but welding must avoid oxygen, moisture, and contamination, with strict purge control.
Which is more widely used?
C-276, by a wide margin, across FGD, chemical processing, and seawater service.
Does Hangbo provide both alloys?
Yes, with complete MTRs, PMI testing, and third-party SGS/TUV inspection.