Hastelloy B-3 (N10675)

What is Hastelloy B-3 and its applications?

Hastelloy B-3 (UNS N10675) is a nickel-molybdenum alloy developed for reducing-acid service. Compared with B-2, it has improved resistance to the formation of detrimental phases during certain thermal exposures.

Acid reaction vessels: Equipment for compatible pure reducing acids.
Chemical processing: Components handling hydrochloric, hydrobromic or sulfuric acid under defined conditions.
Process connections: Hardware where both corrosion and thermal history govern selection.

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Engineering Application & Selection Guide

Its adjusted chemistry delays formation of embrittling phases such as Ni₄Mo. Improved structural stability reduces fabrication concerns but does not guarantee freedom from embrittlement, cracking or service damage.

Hastelloy B-3 stud bolts — For acid-reactor flanges, specify the complete fluid composition and final material condition.
Hastelloy B-3 hex bolts — For thermally exposed enclosures, check the time-temperature history before setting inspection or maintenance intervals.
Hastelloy B-3 socket head cap screws — For chemical instruments, establish thread-forming and surface requirements compatible with the specified final condition.

Use the B-3 and C-276 comparison when process chemistry varies. Reducing-acid performance does not establish suitability for oxidizing contaminants. Check contaminant concentrations, aeration and corrosion data before approving a change in alloy.

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Hastelloy B-3 Composition

Selected nominal composition · wt.%

ElementWeight %

Ni: ≥65%
Mo: 28.5%
Cr: 1.5%
Fe: 1.5%
C: ≤0.01%

ASTM / ASME specifications by product form

Finished-product requirements

Specify the finished-fastener mechanical requirements, condition and inspection separately from the starting-stock specification.

Hastelloy B-3 hex bolt requirements ↗

Fasteners · dimensional references

Product	Reference
Hex bolts	ISO 4014 / ISO 4017 · ASME B18.2.1
Threaded studs	DIN 976-1 · ASME B18.31.2
Hex nuts	ISO 4032 · ASME B18.2.2
Socket head screws	ISO 4762 · ASME B18.3
Flat washers	ISO 7089 / ISO 7090 · ASME B18.21.1
Custom fasteners	Customer drawing

Raw-material specifications

Product form / scope	Reference
Rod & bar	ASTM B335 / ASME SB335
Billet	ASTM B472
Plate, sheet & strip	ASTM B333 / ASME SB333
Seamless pipe & tube	ASTM B622 / ASME SB622
Welded pipe	ASTM B619 / ASME SB619
Welded tube	ASTM B626 / ASME SB626
Fittings	ASTM B366 / B462 · ASME SB366 / SB462

Dimensions do not define material or finished-part compliance. Specify the grade, condition and applicable requirements.

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Hastelloy B-3 Mechanical Properties

Reference sample and condition

Data basis: Published reference sample
Test sample form: Sheet
Sample size: 3.2 mm thickness
Condition: Mill-annealed product context
Test temperature: Room temperature

Key properties	Value
Tensile strength	862 MPa
0.2% yield strength	421 MPa
Elongation	53%

Haynes · B-3 · Nominal composition; Tensile Strength & Elongation · PDF page 11 ↗

Procurement and application guide

Specify the material and final condition

Check oxidizing impurities and actual process conditions.

Material forms in the technical reference: Rod & bar · Billet · Plate · Sheet · Strip · Pipe & tube · Fittings.

Define the finished-part acceptance

Include the material or bolting specification, required final condition, dimensions and quantity. State the service medium, temperature and loading where known. Agree the required tests, inspection coverage and acceptance criteria for the finished part.

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Send a drawing or share the product form and dimensions. Identify any undecided requirements for review rather than copying a typical property value into the purchase order.

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