ASTM B564 Hastelloy B2 Flanges Supplier
ASC LLP supplies ASTM B564 Hastelloy B2 flanges in UNS N10665 for piping systems handling hydrochloric acid, sulfuric acid and other reducing chemical media.
Hastelloy B2 is a nickel–molybdenum alloy containing approximately 28% molybdenum. Its high molybdenum content supports strong corrosion resistance in reducing environments where conventional stainless steels may not provide sufficient service life.
We supply Hastelloy B2 weld neck, slip-on, blind, socket weld, threaded and lap joint flanges according to the material specification, dimensional standard, pressure class, facing, bore and inspection requirements stated in the purchase order.
What Is a Hastelloy B2 Flange?
A Hastelloy B2 flange is a forged nickel–molybdenum piping component used to create a detachable connection between pipes, valves, pumps, pressure vessels and other process equipment.
The material is identified by UNS N10665 and is mainly selected for service involving non-oxidizing or reducing acids. Hastelloy B2 is particularly associated with resistance to hydrochloric acid across a broad range of concentrations and temperatures, subject to actual process conditions.
A complete Hastelloy B2 flange specification normally includes:
- Material grade and UNS number
- ASTM or ASME material specification
- Dimensional standard
- Nominal pipe size
- Pressure class
- Flange type
- Facing
- Bore or connected pipe schedule
- Quantity
- Testing requirements
- Documentation requirements
Material selection should always be based on the complete process environment rather than the alloy name alone.
Hastelloy B2 Flange Specifications
| Specification parameter | Available or applicable details |
| Material grade | Hastelloy B2 |
| UNS designation | UNS N10665 |
| Alloy family | Nickel–molybdenum alloy |
| Material specification | ASTM B564 / applicable ASME material specification |
| Dimensional standard | ASME B16.5 or project-specified standard |
| Nominal size | As required and commercially available |
| Pressure classes | Class 150, 300, 400, 600, 900, 1500 and 2500, subject to size and standard |
| Flange types | Weld neck, slip-on, blind, socket weld, threaded and lap joint |
| Facing options | Raised face, flat face and ring-type joint, where applicable |
| Bore | Standard bore or machined to the connected pipe schedule |
| Manufacturing form | Forged and machined |
| Supply condition | Heat-treated condition according to the applicable material specification |
| Marking | Grade, size, class, heat number and standard, as required |
| Documentation | Material test certificate and inspection documents as agreed in the purchase order |
Flange dimensions must be selected using the applicable dimensional standard, nominal pipe size, flange type and pressure class. ASTM B564 defines requirements for the nickel-alloy forging material; it does not by itself define every flange dimension.
ASTM B564 and ASME B16.5 Requirements
ASTM B564 is a material specification covering nickel-alloy forgings, including UNS N10665. It addresses requirements such as chemical composition, heat treatment, mechanical properties, testing and acceptance of the forging material.
ASME B16.5 is commonly used to define the dimensional and pressure-rating requirements for pipe flanges and flanged fittings within its applicable size range. It covers:
- Pressure–temperature ratings
- Flange dimensions
- Dimensional tolerances
- Facing dimensions
- Bolt-hole arrangement
- Marking
- Testing
- Class designations
For an accurate enquiry, a buyer should not specify only “ASTM B564 flange.” The request should also state the dimensional standard, size, class, flange type and facing.
Example specification:
Hastelloy B2 / UNS N10665, ASTM B564, ASME B16.5, NPS 4, Class 300, weld neck, raised face, bore to Schedule 40.
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Hastelloy B2 Chemical Composition
Hastelloy B2 is principally composed of nickel and molybdenum, with tightly controlled quantities of elements such as chromium, iron, silicon and carbon.
| Element | Nominal or maximum content |
| Nickel | Approximately 69% / balance |
| Molybdenum | Approximately 28% |
| Iron | 2% maximum |
| Chromium | 1% maximum |
| Manganese | 1% maximum |
| Copper | 0.5% maximum |
| Tungsten | 0.5% maximum |
| Silicon | 0.10% maximum |
| Carbon | 0.01% maximum |
The table is intended as a general material overview. Purchase acceptance must be based on the chemical limits in the applicable specification edition and the material test certificate supplied with the product.
Schedule and Size Chart
| Flange Type | Nominal Size (inches) | Schedule | Outside Diameter (OD) (mm) | Thickness (mm) | Weight (kg) |
| Slip-On Flange | 1/2″ to 24″ | SCH 10, 20, 40, 80 | 21.34 – 609.6 | 6.35 – 15.88 | 0.45 – 350.7 |
| Weld Neck Flange | 1/2″ to 24″ | SCH 10, 20, 40, 80 | 21.34 – 609.6 | 6.35 – 15.88 | 0.5 – 368.9 |
| Blind Flange | 1/2″ to 24″ | SCH 10, 20, 40, 80 | 21.34 – 609.6 | 6.35 – 15.88 | 0.55 – 380.1 |
| Socket Weld Flange | 1/2″ to 4″ | SCH 40, 80, 160, XXS | 21.34 – 114.3 | 7.47 – 13.41 | 0.55 – 12.0 |
| Threaded Flange | 1/2″ to 4″ | SCH 40, 80, 160, XXS | 21.34 – 114.3 | 7.47 – 13.41 | 0.6 – 13.0 |
| Lap Joint Flange | 1/2″ to 24″ | SCH 10, 20, 40, 80 | 21.34 – 609.6 | 6.35 – 15.88 | 0.5 – 370.0 |
Mechanical Properties Chart
| Property | Value |
| Tensile Strength | 110 ksi (758 MPa) min |
| Yield Strength | 51 ksi (350 MPa) min |
| Elongation | 40% min (in 50 mm) |
| Hardness | 85 HRB max |
| Modulus of Elasticity | 206 GPa (at 20°C) |
| Impact Strength | Excellent (Charpy V-Notch) |
Corrosion Resistance of Hastelloy B2 Flanges
Resistance to Reducing Acids
The principal benefit of Hastelloy B2 is its resistance to reducing chemical environments. It may be considered for systems handling:
- Hydrochloric acid
- Sulfuric acid under suitable conditions
- Hydrobromic acid
- Acetic acid
- Formic acid
- Phosphoric acid
- Hydrogen chloride gas
- Other non-oxidizing chemical media
Its high molybdenum content is the main contributor to its performance in these environments.
Hydrochloric Acid Service
Hydrochloric acid is highly aggressive to many stainless steels and common metallic materials. Hastelloy B2 may provide substantially improved resistance in hydrochloric acid service, although suitability depends on:
- Acid concentration
- Operating temperature
- Flow velocity
- Aeration
- Contaminants
- Oxidizing impurities
- Crevice conditions
- Fabrication quality
An engineer should review actual corrosion data for the intended concentration and temperature before final material selection.
Limitations in Oxidizing Environments
Hastelloy B2 contains very little chromium compared with nickel–chromium–molybdenum alloys such as Hastelloy C22 or C276. It should therefore not be promoted as a universal alloy for every corrosive environment.
Oxidizing chemicals or oxidizing contaminants can reduce its corrosion performance. Careful evaluation is required where the process contains:
- Ferric salts
- Cupric salts
- Hypochlorites
- Free chlorine
- Strong oxidizing acids
- Dissolved oxygen under certain conditions
- Mixed oxidizing and reducing chemicals
For mixed or strongly oxidizing service, another nickel alloy may be more appropriate.
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Hastelloy B2 vs Hastelloy B3 Flanges
| Selection factor | Hastelloy B2 | Hastelloy B3 |
| UNS designation | N10665 | N10675 |
| Alloy family | Nickel–molybdenum | Nickel–molybdenum |
| Reducing-acid resistance | Excellent under suitable conditions | Excellent under suitable conditions |
| Thermal stability | More sensitive to undesirable phase formation | Improved thermal stability |
| Fabrication tolerance | Requires careful thermal control | Generally offers improved fabrication stability |
| Grade selection | Suitable where specifically required by design | Often considered where improved structural stability is needed |
The final selection must be made by the responsible material or process engineer. Existing plant specifications, compatibility with installed equipment, welding procedures and regulatory requirements may also affect the decision.
Thermal Stability and Fabrication Considerations
Hastelloy B2 is an earlier-generation nickel–molybdenum alloy. Exposure within certain intermediate temperature ranges during fabrication, heat treatment or service can lead to the formation of undesirable intermetallic phases.
These phases may reduce ductility and affect corrosion resistance. For this reason:
- Heat treatment must follow the material specification.
- Uncontrolled intermediate-temperature exposure should be avoided.
- Welding procedures should be properly qualified.
- Flanges should be supplied in the correct heat-treated condition.
- Material identification and heat traceability should be maintained.
- The complete service temperature history should be considered.
Hastelloy B3 was developed with improved thermal and structural stability compared with Hastelloy B2. The grades should not be treated as automatically interchangeable; selection should be based on design requirements, procurement specifications and engineering approval.
Types of Hastelloy B2 Flanges
Hastelloy B2 Weld Neck Flanges
A weld neck flange has a tapered hub and is joined to the pipe by a full-penetration butt weld. It is commonly selected for high-integrity piping connections, elevated pressures, cyclic service and systems where stress distribution is important.
The bore should be matched to the connected pipe wall thickness or schedule.
Hastelloy B2 Slip-On Flanges
A slip-on flange is fitted over the pipe and normally connected by internal and external fillet welds. It can simplify alignment and fabrication, but its suitability should be evaluated for the operating pressure, temperature and corrosion environment.
Hastelloy B2 Blind Flanges
A blind flange closes the end of a piping line, valve opening or equipment nozzle. It enables isolation and future access while maintaining a bolted flange connection.
Blind flange thickness and rating vary significantly with size and pressure class.
Hastelloy B2 Socket Weld Flanges
Socket weld flanges are generally used for smaller pipe sizes. The pipe is inserted into the socket and joined using a fillet weld.
The internal crevice created by the socket configuration should be considered when the service fluid is corrosive or prone to deposit formation.
Hastelloy B2 Threaded Flanges
Threaded flanges connect to externally threaded pipe without a circumferential weld. Their use is normally limited by the process conditions, applicable piping code and risk of leakage through the threaded connection.
Hastelloy B2 Lap Joint Flanges
Lap joint flanges are used with stub ends. They can make bolt-hole alignment easier and may allow the backing flange to rotate independently of the stub end.
The material combination of the stub end, backing flange, bolting and gasket must be evaluated for corrosion compatibility.
Flange Pressure Classes and Facing Options
Hastelloy B2 flanges may be specified in ASME pressure classes such as:
- Class 150
- Class 300
- Class 400
- Class 600
- Class 900
- Class 1500
- Class 2500
Availability varies according to nominal size, flange type, dimensional standard and manufacturing capability.
Common facing options include:
Raised Face
Raised-face flanges concentrate gasket loading over a smaller sealing area and are widely used in process piping.
Flat Face
Flat-face flanges provide a full contact surface. They are used only where required by the mating equipment, piping specification or design standard.
Ring-Type Joint
RTJ flanges use a machined groove and metallic ring gasket. They are commonly selected for higher-pressure or more severe services where an RTJ connection is specified.
Facing finish, gasket material, bolting and tightening procedure are all important to the performance of the completed joint.
Hastelloy B2 Flange Manufacturing Process
ASC LLP supplies forged and machined Hastelloy B2 flanges sourced according to customer specifications.
A typical production route may include:
- Raw-material and heat-number verification
- Cutting of approved forging stock
- Controlled heating
- Forging or ring rolling
- Heat treatment
- Rough machining
- Final dimensional machining
- Facing and gasket-surface machining
- Bolt-hole drilling
- Bore machining
- Dimensional inspection
- Material identification
- Testing and documentation
- Cleaning, marking and export packing
The actual manufacturing route depends on the flange type, size, class, applicable specification and manufacturer’s approved procedure.
Applications of Hastelloy B2 Flanges
Hastelloy B2 flanges may be used in equipment and piping handling suitable reducing chemical media, including:
- Hydrochloric acid process lines
- Sulfuric acid systems under approved conditions
- Acid transfer piping
- Chemical reactors
- Acid storage and transfer equipment
- Evaporators
- Heat exchanger connections
- Absorption towers
- Distillation equipment
- Pharmaceutical chemical-processing lines
- Specialty chemical plants
- Pulp and paper chemical systems
- Pickling and acid-cleaning equipment
- Hydrogen chloride handling systems
Hastelloy B2 should not be selected solely because an application is described as “chemical,” “marine,” “oil and gas” or “high temperature.” The exact chemical composition, concentration, temperature and contaminants must be evaluated.
Why Source Hastelloy B2 Flanges from ASC LLP?
ASC LLP supports industrial, EPC and international procurement requirements for nickel-alloy piping products.
Our supply approach focuses on:
- Material supplied according to the purchase specification
- Clear identification of grade and UNS number
- Coordination of required dimensions and pressure class
- Heat-number traceability
- Inspection and documentation support
- Third-party inspection coordination where agreed
- Suitable packing for domestic or export dispatch
- Technical-commercial quotation based on complete buyer information
- Support for standard and project-specific requirements
We recommend that customers provide a complete material requisition or datasheet so that the offered flange matches the intended piping system.
Frequently Asked Questions
What is the UNS number of Hastelloy B2?
The UNS designation for Hastelloy B2 is N10665.
What is ASTM B564?
ASTM B564 is a material specification covering specified nickel-alloy forgings. Flange dimensions and pressure ratings must be specified separately using an applicable dimensional standard such as ASME B16.5.
Is Hastelloy B2 suitable for hydrochloric acid?
Hastelloy B2 is widely associated with resistance to hydrochloric acid and other reducing acids. Final suitability depends on acid concentration, operating temperature, impurities, aeration and system conditions.
Is Hastelloy B2 suitable for seawater?
Hastelloy B2 should not automatically be selected for seawater service. Its low chromium content means it is not the same as nickel–chromium–molybdenum alloys developed for broad chloride, pitting and crevice-corrosion resistance. A materials engineer should review the service conditions.
Are Hastelloy B2 and Hastelloy B3 the same?
No. Hastelloy B2 is UNS N10665, while Hastelloy B3 is UNS N10675. B3 was developed with improved thermal and structural stability compared with B2.
Global Reach
ASC LLP boasts a robust global presence, committed to delivering unparalleled service and quality to clients around the world. Our dedication to prompt delivery and exceptional customer care sets us apart in the industry. Major corporations across the USA, Europe, Asia, and other regions place their trust in our high-quality ASTM B564 Hastelloy B2 Flanges. This widespread trust underscores our reputation for reliability and excellence. By consistently meeting and exceeding the expectations of our international clientele, we continue to solidify our position as a leader in the global steel market.
Countries We Export To
UNITED STATES, EUROPE, UK, UAE, SAUDI ARABIA, OMAN, KUWAIT, JORDAN, QATAR, INDONESIA, MALAYSIA, BRAZIL, SPAIN, ITALY, FRANCE, GERMANY, BAHRAIN, SRI LANKA, AZERBAIJAN, AUSTRALIA, AUSTRIA, PHILIPPINES, TURKEY, RUSSIA, IRAN, IRAQ, CANADA, KOREA, JAPAN, YEMEN, FINLAND, ZIMBABWE, HUNGARY, PORTUGAL, VIETNAM, MOROCCO, THAILAND, SOUTH AFRICA, MEXICO, SINGAPORE, GREECE, KUWAIT, POLAND, NEW ZEALAND, SWEDEN, SWITZERLAND, BELGIUM, BHUTAN, BANGLADESH, TAIWAN, ROMANIA, CAMBODIA, KAZAKHSTAN, AFGHANISTAN.
