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Ferralium 255 Nuts Manufacturer & Exporter in India

Explore Ferralium 255 Nuts Manufacturer & Exporter in India manufactured for demanding industrial applications with reliable strength, corrosion resistance and compliance with international standards.
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-196

Min Temp

870

Max Temp

🌡

870

Suitable for continuous service up to approximately 870°C under typical operating conditions.

⚡

620

Typical tensile strength around 620 MPa depending on product form and heat treatment.

🛡

Very Good

Very Good corrosion resistance in a wide range of industrial environments.

⚖

8

Typical density is approximately 8.0 g/cm³.

Product Overview

What are Ferralium 255 Nuts?

Ferralium 255 nuts are high-performance super duplex stainless steel fasteners manufactured from UNS S32550 bar or forgings, conforming to ASTM A182 F61 and ASTM A479. With a dual-phase microstructure of austenite and ferrite, Ferralium 255 offers exceptional resistance to pitting, crevice, and stress corrosion cracking, even in aggressive chloride and acidic environments.

With a PREN (Pitting Resistance Equivalent Number) of 40+, Ferralium 255 nuts are specified for critical bolted joints in seawater, desalination, chemical processing, and offshore oil & gas applications where standard duplex or 316/904L stainless steel is inadequate. Their high strength (yield >550 MPa) allows for weight savings and compact joint designs.

Quick Specifications

MaterialFerralium 255 (Super Duplex Stainless Steel)
UNS NumberS32550
DIN Number1.4507
Material StandardASTM A182 F61 / ASTM A479
Nut Standard (Metric)DIN 934 / ISO 4032
Nut Standard (Inch)ASME B18.2.2
Thread FormISO Metric / UNC / UNF
Diameter RangeM6-M64 / ¼"-2½"
Tensile Strength800 MPa (116 ksi) min
Yield Strength550 MPa (80 ksi) min
HardnessMax 28 HRC / 290 HB
? All material certified by NABL-accredited laboratory. PMI and ferrite content verification available on request.

Complete the Fastener Set

Other Ferralium 255 Fastener Products Available from RealBolt

RealBolt also manufactures the complete Ferralium 255 fastener range from certified super duplex stainless steel bar stock, including Ferralium 255 Bolts, Ferralium 255 Screws, Ferralium 255 Washers, Ferralium 255 Studs, and Ferralium 255 Threaded Rods. All Ferralium 255 fastener types are produced to ASTM with full EN 10204 MTC 3.1/3.2 documentation.
Ferralium 255 Bolts
Ferralium 255 Screws
Ferralium 255 Washers
Ferralium 255 Studs
Ferralium 255 Threaded Rods

Technical Data

Ferralium 255 Nuts Dimensions, Sizes & Thread Standards

Ferralium 255 Nuts are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 934 (hex nut) / ISO 4032. Custom thread pitches and heavy hex per ASME B18.2.2 available. Inch series per ASME B18.2.2. All Ferralium 255 nuts dimensions are verified against applicable DIN, ISO, and ASME B18

Hex Nut Dimensions - Metric (DIN 934 / ISO 4032)

Size (M)Pitch (mm)A/F (mm)Height (mm)
M61.0105.0
M81.25136.5
M101.5178.0
M121.751910.0
M162.02413.0
M202.53016.0
M243.03619.0
M303.54624.0
M364.05529.0
M424.56534.0
M485.07538.0
M565.58545.0
M646.09551.0

Dimensional & Material Standards

StandardCoversThread
DIN 934Hex nutsMetric
ISO 4032Hex nutsMetric
ASME B18.2.2Hex & heavy hex nutsUNC/UNF
ISO 4033Heavy hex nutsMetric
BS 1768Hex nuts (inch)BSW/BSF
Material StandardRequirement
ASTM A182 F61Forged nuts - UNS S32550
ASTM A479Bar/rod - UNS S32550
NACE MR0175Sour service =28 HRC
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

Ferralium 255 Chemical Composition

Ferralium 255 Nuts are manufactured from a high-alloy ferritic-austenitic steel containing chromium (24–26%), molybdenum (3.5–5%), and nitrogen (0.24–0.32%) per ASTM. These precise elemental limits produce PREN ≥ 40 — confirming seawater pitting immunity — and deliver the 550 MPa minimum yield strength required for NORSOK M-630 subsea qualification.

Chemical Composition per ASTM A182 F61 / ASTM A479

ElementComposition (%)
Chromium (Cr)24.0-26.0
Nickel (Ni)4.5-6.5
Molybdenum (Mo)2.9-3.5
Copper (Cu)1.5-2.0
Nitrogen (N)0.10-0.25
Silicon (Si)0.70 max
Manganese (Mn)1.5 max
Carbon (C)0.04 max
Phosphorus (P)0.04 max
Sulphur (S)0.03 max
Iron (Fe)Balance
? All heats verified by NABL-accredited spectrometry. PMI and ferrite content verification available on request.

Why Ferralium 255 Alloy Composition Matters for Nuts

Cr (24–26%) & Mo (2.9–3.5%) — Pitting & Crevice Resistance
The high chromium and molybdenum content gives Ferralium 255 nuts a PREN >40, ensuring outstanding resistance to pitting and crevice corrosion in seawater and aggressive chemical environments, even under nut bearing faces.
Cu (1.5–2.0%) — Acid Resistance
Copper enhances resistance to sulphuric, phosphoric, and organic acids, making Ferralium 255 nuts ideal for acid process plant and fertilizer equipment.
N (0.10–0.25%) — Strength & SCC Resistance
Nitrogen increases yield strength and improves resistance to chloride stress corrosion cracking, critical for nuts in high-load, high-chloride environments.

Fastener Performance

Ferralium 255 Nuts Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for Ferralium 255 Nuts per ASTM. Ferralium 255 nuts achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Nut SizeRecommended Torque (Nm)Clamp Load (kN)
M129040
M1622080
M20440125
M24760180
M301550290
M362700420
M424300580
M486400770
?? Anti-galling: Use molybdenum-based or super duplex-compatible anti-seize. Lubricated values assume K=0.15. Avoid copper-based anti-seize in chloride service.

Industry Applications

Ferralium 255 Nuts Applications — Industries & End Uses

Ferralium 255 Nuts from RealBolt are specified across subsea oil and gas, FPSOs, desalination, and offshore where very good corrosion resistance and 620 MPa tensile strength are required for reliable fastener performance. Click each industry below for detailed application examples.
Ferralium 255 nuts are the preferred choice for seawater intake screens, reverse osmosis (RO) plant bolted joints, and desalination piping flanges due to their superior resistance to pitting and crevice corrosion in high-chloride environments.
Used in acid process plant reactors, phosphoric acid evaporators, and fertilizer equipment where resistance to sulphuric, phosphoric, and organic acids is critical and where 316L or 904L nuts fail.
Specified for subsea pipeline flanges, riser clamps, and splash zone structural connections on offshore platforms, where high strength and immunity to chloride stress corrosion cracking are essential.
Ferralium 255 nuts are used in bleach plant washers, digesters, and chemical recovery systems where resistance to chloride-bearing liquors and high mechanical strength are required.

Ferralium 255 Nuts Standards & International Certifications

Ferralium 255 Nuts 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 3.2 (third-party), NACE MR0175/ISO 15156, NORSOK M-630, Charpy impact certificates, and PMI (XRF) reports — available on request for all orders.
Standards
DIN 934 ISO 4032 ASME B18.2.2 EN ISO 4032 IS 1364 IS 1367 IS 12427
Certifications
ISO 9001:2015NACE MR0175NABL LabPED 2014/68/EUMTC 3.1 / 3.2

Buy Ferralium 255 Nuts from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified Ferralium 255 Nuts — 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.
022-6743-7972
+91 90226 36025
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Answers for Buyers

Ferralium 255 Nuts — Frequently Asked Questions

Browse expert answers to common questions about Ferralium 255 Nuts from RealBolt — covering PREN ≥ 40, NORSOK M-630, NACE MR0175, ASTM A182 F53/F55, sizes, and EN 10204 3.2 third-party documentation. Contact our technical team directly for project-specific guidance on Ferralium 255 nuts selection and pricing.
Ferralium 255 hex nuts are available to DIN 934 (metric), ISO 4032, ISO 4033 (heavy hex), and ASME B18.2.2 (inch hex and heavy hex). Custom thread forms (UNC, UNF, BSW, BSF) and special coatings are available on request with typical lead times of 2-3 weeks.
Use molybdenum-based or super duplex-compatible anti-seize (such as Loctite LB 8012 or Jet-Lube SS-30) on Ferralium 255 nuts. Apply to threads and nut bearing face to prevent galling. Avoid copper-based anti-seize in chloride-rich or seawater service to prevent galvanic corrosion.
Yes – Ferralium 255 nuts are specifically designed for high-chloride environments such as seawater, desalination, and marine applications. Their PREN >40 ensures immunity to pitting and crevice corrosion, even under nut faces and in crevices. They are widely specified for RO plants, seawater piping, and offshore structures.
No formal MOQ for standard sizes (M12-M36) held ex-stock – we supply from single pieces for urgent maintenance. Custom sizes or non-standard threads typically require a 10 kg minimum. Quantity price breaks are available at 50 pcs, 200 pcs, and 500 pcs.

Industrial Cities We Serve:

  • Ahmedabad
  • Aurangabad
  • Bengaluru
  • Chennai
  • Coimbatore
  • Faridabad
  • Gandhidham
  • Greater Noida
  • Gurugram
  • Hazira
  • Hosur
  • Hyderabad
  • Jamnagar
  • Jamshedpur
  • Ludhiana
  • Mumbai
  • Mundra
  • Mysuru
  • Nagpur
  • Nashik
  • Navi Mumbai
  • Noida
  • Pune
  • Rajkot
  • Sanand
  • Surat
  • Thane
  • Tiruppur
  • Vadodara
  • Visakhapatnam

Countries We Export To:

  • US
  • Canada
  • Mexico
  • Germany
  • UK
  • France
  • Italy
  • Spain
  • Netherlands
  • Belgium
  • Poland
  • Sweden
  • Norway
  • Denmark
  • Turkey
  • UAE
  • Saudi Arabia
  • Qatar
  • Oman
  • Kuwait
  • Bahrain
  • South Africa
  • Egypt
  • Nigeria
  • Australia
  • New Zealand
  • Singapore
  • Malaysia
  • Indonesia
  • Thailand
  • Vietnam
  • South Korea
  • Japan
  • Brazil