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Hastelloy B3 Screws Manufacturer & Exporter in India

Explore Hastelloy B3 Screws Manufacturer & Exporter in India manufactured for demanding industrial applications with reliable strength, corrosion resistance and compliance with international standards.
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-200

Min Temp

1100

Max Temp

🌡

1100

Suitable for continuous service up to approximately 1100°C under typical operating conditions.

⚡

800

Typical tensile strength around 800 MPa depending on product form and heat treatment.

🛡

Excellent

Excellent corrosion resistance in a wide range of industrial environments.

⚖

8.9

Typical density is approximately 8.9 g/cm³.

Product Overview

What are Hastelloy B3 Screws?

Hastelloy B3 screws are nickel-molybdenum alloy fasteners machined from UNS N10675 bar stock conforming to ASTM B335. The alloy’s exceptionally high molybdenum content (28.5-31.5%) delivers outstanding resistance to hydrochloric acid at all concentrations and temperatures, including boiling HCl – a performance level unmatched by any stainless steel or standard nickel alloy.

Hastelloy B3 screws are specified for chemical process equipment, reactor closures, and acid handling systems where reducing acid environments would rapidly corrode alternative materials. The alloy’s improved thermal stability over its predecessor B2 eliminates the risk of precipitation in the heat-affected zone, making B3 screws suitable for welded assemblies without post-weld heat treatment.

Quick Specifications

MaterialHastelloy B3
UNS NumberN10675
DIN Number2.4600
Material StandardASTM B335
Screw Standard (Metric)DIN 912 / DIN 933 / ISO 4762
Screw Standard (Inch)ASME B18.3 / ASME B18.6.3
Thread FormISO Metric / UNC / UNF
Diameter RangeM4-M64 / #10-2½"
Tensile Strength760 MPa (110 ksi) min
Yield Strength350 MPa (51 ksi) min
HardnessMax 35 HRC / 241 HB
? All material certified by NABL-accredited laboratory. PMI available on request.

Complete the Fastener Set

Other Hastelloy B3 Fastener Products Available from RealBolt

RealBolt also manufactures the complete Hastelloy B3 fastener range from certified nickel-molybdenum-chromium superalloy bar stock, including Hastelloy B3 Bolts, Hastelloy B3 Nuts, Hastelloy B3 Washers, Hastelloy B3 Studs, and Hastelloy B3 Threaded Rods. All Hastelloy B3 fastener types are produced to ASTM with full EN 10204 MTC 3.1/3.2 documentation.
Hastelloy B3 Bolts
Hastelloy B3 Nuts
Hastelloy B3 Washers
Hastelloy B3 Studs
Hastelloy B3 Threaded Rods

Technical Data

Hastelloy B3 Screws Dimensions, Sizes & Thread Standards

Hastelloy B3 Screws are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 912 (socket head cap screws) / DIN 933 (hex full thread) / ISO 4762. Custom lengths in 5mm increments. Inch dimensions available per ASME B18.3. All Hastelloy B3 screws dimensions conform to applicable DIN, ISO, and ASME B18 standards.

Socket Head Cap Screw Dimensions - Metric (DIN 912 / ISO 4762)

Size (M)Pitch (mm)Head Dia (mm)Head Ht (mm)Socket (mm)Max L (mm)
M40.77.04.03100
M50.88.55.04120
M61.010.06.05150
M81.2513.08.06200
M101.516.010.08250
M121.7518.012.010300
M162.024.016.014400
M202.530.020.017500
M243.036.024.019600
M303.545.030.022800
M364.054.036.0271000
M424.563.042.0321000
M485.072.048.0361200
M565.584.056.0411500
M646.096.064.0462000

Dimensional & Material Standards

StandardCoversThread
DIN 912Socket head cap screwsMetric
DIN 933Hex screws, full threadMetric
ISO 4762Socket head cap screwsMetric
ISO 4017Hex head screws, full threadMetric
ASME B18.3Socket head cap screwsUNC/UNF
ASME B18.6.3Machine screwsUNC/UNF
DIN 7984Low head socket cap screwsMetric
Material StandardRequirement
ASTM B335Bar/rod - UNS N10675
ASTM B462Forgings - UNS N10675
ASTM F468Fastener mechanical properties
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

Hastelloy B3 Chemical Composition

Hastelloy B3 Screws derive their exceptional acid corrosion resistance from a precisely controlled nickel-molybdenum-chromium composition per ASTM. High molybdenum and tungsten content suppresses pitting and reducing-acid attack; ultra-low carbon (0.01% max) eliminates sensitization risk in welded assemblies. Full elemental composition is certified in the EN 10204 MTC supplied with every Hastelloy B3 screws order from RealBolt.

Chemical Composition per ASTM B335

ElementComposition (%)
Nickel (Ni)Balance (min 65%)
Molybdenum (Mo)28.5-31.5%
Chromium (Cr)1.0-3.0%
Iron (Fe)3.0% max
Cobalt (Co)3.0% max
Tungsten (W)3.0% max
Manganese (Mn)3.0% max
Carbon (C)0.01% max
Silicon (Si)0.10% max
Aluminium + Titanium0.50% max combined
? All heats verified by NABL-accredited spectrometry. PMI available on request.

Why Hastelloy B3 Alloy Composition Matters for Screws

Mo (28.5–31.5%) — Reducing Acid Resistance
The ultra-high molybdenum content is the defining characteristic of Hastelloy B3. It provides exceptional resistance to hydrochloric acid at all concentrations up to boiling point, as well as sulfuric, acetic, and phosphoric acids in reducing conditions — environments that destroy standard stainless steels within hours.
Ultra-Low Carbon (0.01% max) — Thermal Stability
The near-zero carbon ceiling in B3 eliminates carbide precipitation at grain boundaries during welding or slow cooling through the 700–870°C sensitisation range. This is the critical improvement over Hastelloy B2, making B3 screws safe for use in welded assemblies without post-weld heat treatment.
Controlled Cr, W, and Fe — Balanced Reducing/Oxidising Tolerance
Small additions of chromium (1–3%) and tungsten (up to 3%) extend resistance to mildly oxidising contaminants that may be present in otherwise reducing acid streams, giving B3 screws broader process tolerance than pure Ni-Mo alloys of earlier generations.

Fastener Performance

Hastelloy B3 Screws Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for Hastelloy B3 Screws per ASTM. Hastelloy B3 screws achieve 800 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Tightening Torque Reference - Hastelloy B3 Screws

Screw SizeDry (Nm)Lubricated (Nm)Clamp Load (kN)
M822189
M10443518
M12766130
M1618514870
M20365292110
M24630504160
M3012601008255
M3621901752370
?? Anti-galling: Use nickel-based anti-seize (Molykote P-37 or equivalent). Lubricated values assume K=0.15. Never use copper-based anti-seize on nickel alloys - galvanic corrosion risk in acid environments.

Industry Applications

Hastelloy B3 Screws Applications — Industries & End Uses

Hastelloy B3 Screws from RealBolt are specified across chemical processing, pharmaceutical, oil and gas, and FGD where excellent corrosion resistance and 800 MPa tensile strength are required for reliable fastener performance. Click each industry below for detailed application examples. Select an industry below to see specific Hastelloy B3 screws application details and RealBolt stock availability.
Hastelloy B3 screws are the primary fastener choice for HCl reactor closures, acid storage tank internals, and chemical feed system flanges. The alloy withstands hydrochloric acid at all concentrations up to boiling point – a condition that causes rapid corrosion in all grades of stainless steel and even Hastelloy C276. Specified per ASTM B335 / UNS N10675.
Reactor vessel cover screws, agitator shaft fasteners, and internal fitting hardware in pharmaceutical synthesis equipment handling reducing acid media, acetic acid, and mixed organic acid streams. Hastelloy B3 screws meet FDA material traceability requirements and are compatible with CIP/SIP cleaning cycles using dilute HCl or HNO3.
Screw fasteners for heat exchanger covers, acid cooler channel heads, and pickling tank structural connections in steel pickling lines and sulfuric acid concentration units. Hastelloy B3 outperforms B2 in slow-cooled or welded assemblies due to its superior thermal stability, eliminating the risk of knife-line attack.
Socket head cap screws and machine screws for bleach plant equipment including chlorine dioxide generators, washer drum covers, and chemical feed piping flanges. The alloy’s resistance to reducing chloride environments and dilute acid bleaching liquors makes it a reliable alternative where Hastelloy C276 is over-specified.

Hastelloy B3 Screws Standards & International Certifications

Hastelloy B3 Screws from RealBolt Engineering Industries are manufactured to internationally recognised fastener dimensional standards covering thread form, tolerances, strength grades, and quality requirements. Every batch ships with EN 10204 MTC 3.1/3.2, PMI (XRF), NACE MR0175/ISO 15156, and NABL-accredited lab reports — available on request for all orders.
Standards
DIN 912 DIN 913 DIN 914 DIN 915 DIN 916 DIN 6912 ISO 4762 ISO 10642 ASME B18.3 EN ISO 4762 IS 1367
Certifications
ISO 9001:2015NACE MR0175NABL LabPED 2014/68/EUMTC 3.1 / 3.2

Buy Hastelloy B3 Screws from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified Hastelloy B3 Screws — for competitive pricing, EN 10204 MTC 3.1/3.2 documentation, and fast Mumbai dispatch. Standard sizes are ex-stock; custom dimensions accepted with 2–3 week lead time. Request your quote today.
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Answers for Buyers

Hastelloy B3 Screws — Frequently Asked Questions

Browse expert answers to common questions about Hastelloy B3 Screws from RealBolt — covering acid corrosion resistance, NACE MR0175 compliance, ASTM standards, available sizes, and MTC documentation. Contact our technical team directly for project-specific guidance on Hastelloy B3 screws selection and pricing.
Hastelloy B3 screws are manufactured to DIN 912 (socket head cap screws, metric), ISO 4762 (socket head cap screws), DIN 933 (hex screws, full thread), and ASME B18.3 (socket head cap screws, inch). Machine screws are available per ASME B18.6.3 in UNC and UNF thread forms. Custom drive types including Torx, Phillips, and slotted heads are available on request with 15 working day lead time.
Yes – Hastelloy B3 (UNS N10675) offers a critical advantage over B2 (UNS N10665) in fastener applications. B3’s ultra-low carbon content (0.01% max) and controlled silicon level eliminate the risk of carbide and intermetallic precipitation during slow cooling or welding. B3 screws can be used in welded assemblies and equipment that cycles through the 700-870°C sensitisation range without developing knife-line attack or grain boundary corrosion – a known failure mode with B2 fasteners in the same conditions.
Hastelloy B3 screws are optimised for reducing acid environments and should not be specified in strongly oxidising conditions. Concentrated nitric acid, hot concentrated sulfuric acid above 60%, ferric chloride solutions, and wet chlorine gas will attack B3 at elevated temperatures. For mixed oxidising-reducing or chloride-rich oxidising environments, Hastelloy C276 (UNS N10276) or Hastelloy C22 (UNS N06022) screws are the correct specification. Contact our engineering team for a corrosion environment assessment before ordering.
In reducing acid service, Hastelloy B3 screws are rated to approximately 538°C continuous service. Above this temperature in reducing environments, molybdenum-rich phases can begin to precipitate, reducing corrosion resistance. For high-temperature oxidising service above 500°C, Hastelloy C276 or Inconel 625 screws are more appropriate. Hastelloy B3 is not recommended for prolonged service in the 700-870°C range regardless of environment due to sigma phase formation risk.

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