Hastelloy Alloys
Hastelloy B-2 (UNS N10665) — Composition, Properties & Supply
Hastelloy B-2 (UNS N10665) is a nickel-molybdenum alloy with 26–30% molybdenum, giving excellent resistance to reducing media such as hydrochloric and sulphuric acid. Low carbon and silicon keep the weldment free from intergranular attack, making it a specialist material for HCl and acetic acid plant.
What is the chemical composition of Hastelloy B-2?
| Element | Symbol | Content (wt%) |
|---|---|---|
| Ni | Ni | Balance |
| Mo | Mo | 26.0–30.0 |
| Fe | Fe | ≤ 2.0 |
| Cr | Cr | ≤ 1.0 |
| Co | Co | ≤ 1.00 |
| C | C | ≤ 0.02 |
| Si | Si | ≤ 0.10 |
| Mn | Mn | ≤ 1.00 |
| P | P | ≤ 0.040 |
| S | S | ≤ 0.030 |
Values are typical specification limits. Actual heat analysis is reported on the EN 10204 3.1 mill test certificate supplied with each shipment.
What are the mechanical properties of Hastelloy B-2?
| Property | Value | Note |
|---|---|---|
| Tensile strength | ≥ 760 MPa | Room temperature |
| Yield strength (0.2% offset) | ≥ 350 MPa | Room temperature |
| Elongation | ≥ 40 % | Gauge length 50 mm / 4D |
| Hardness | ≤ 200 HB | Brinell / Rockwell |
What are the physical properties of Hastelloy B-2?
| Property | Value |
|---|---|
| Density | 9.22 g/cm³ |
| Melting range | 1330–1380 °C |
| Thermal conductivity | 11.0 W/m·K |
| Elastic modulus | 217 GPa |
| Maximum service temperature | 1000 °C |
What are the key characteristics of Hastelloy B-2?
- Excellent across all hydrochloric acid concentrations and temperatures
- Resists non-oxidising acids — sulphuric, phosphoric, acetic
- Immune to chloride stress-corrosion cracking; resists pitting
- Caution: not suitable where oxidising ions (Fe³⁺, Cu²⁺) are present
Where is Hastelloy B-2 used?
- Hydrochloric acid production, storage and transfer equipment
- Acetic acid and acetic anhydride plant
- Alkylation and catalyst recovery systems
- Sulphuric acid recovery and concentration
- Agrochemical and dye intermediate reactors
Which standards and specifications cover Hastelloy B-2?
What product forms are available?
Frequently asked questions
Why can't Hastelloy B-2 be used in hydrochloric acid containing oxidising impurities?
B-2 relies on a molybdenum-rich film that is stable only in reducing environments. When Fe³⁺, Cu²⁺, dissolved oxygen or nitric acid are present, the corrosion potential shifts and the film breaks down, sharply increasing the corrosion rate. Switch to chromium-bearing C-22 or C-2000 in that case.
What is the difference between B-2 and B-3?
B-3 (UNS N10675) has a tuned chemistry with small chromium addition and controlled iron, greatly improving thermal stability. It is far less prone than B-2 to precipitating Ni-Mo intermetallic phases during mid-temperature (600–800 °C) processing, so welding and hot forming are safer and properties more consistent. B-3 is preferred for new projects.
Need Hastelloy B-2 bar, tube, plate or forgings?
Send the grade, dimensions, standard and quantity. We answer within 10 minutes on working days and quote within 24 hours, with EN 10204 3.1 certification.
Request a Quote Chat on WhatsApp +86-156-1827-9078