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Alloy 20 (Carpenter 20Cb-3) Nuts Manufacturer & Exporter in India

Explore Alloy 20 (Carpenter 20Cb-3) 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 Alloy 20 (Carpenter 20Cb-3) Nuts?

Alloy 20 (Carpenter 20Cb-3) nuts are high-performance austenitic stainless steel fasteners manufactured from UNS N08020 bar stock, conforming to ASTM B473. Designed for exceptional resistance to sulfuric acid, chloride stress corrosion cracking, and pitting, Alloy 20 nuts are widely specified in chemical processing, pharmaceutical, and food industries. The addition of copper (3-4%) and niobium (columbium) stabilizes the alloy against intergranular corrosion, making these nuts ideal for aggressive acid environments where standard stainless steels fail.

Alloy 20 nuts are available in hex, heavy hex, and lock nut configurations, meeting ASME, DIN, and ISO standards. They are the preferred choice for bolted joints in sulfuric acid piping, heat exchangers, and pressure vessels, offering reliable performance and long service life in the harshest chemical environments.

Quick Specifications

MaterialAlloy 20 (Carpenter 20Cb-3)
UNS NumberN08020
DIN Number2.4660
Material StandardASTM B473
Nut Standard (Metric)DIN 934 / ISO 4032
Nut Standard (Inch)ASME B18.2.2
Thread FormISO Metric / UNC / UNF
Diameter RangeM6-M100 / ¼"-4"
Tensile Strength551 MPa (80 ksi) min
Yield Strength241 MPa (35 ksi) min
HardnessMax 241 HB
? All material certified by NABL-accredited laboratory. PMI and corrosion test reports available on request.

Complete the Fastener Set

Other Alloy 20 (Carpenter 20Cb-3) Fastener Products Available from RealBolt

RealBolt also manufactures the complete Alloy 20 (Carpenter 20Cb-3) fastener range — Alloy 20 (Carpenter 20Cb-3) Bolts, Alloy 20 (Carpenter 20Cb-3) Screws, Alloy 20 (Carpenter 20Cb-3) Washers, Alloy 20 (Carpenter 20Cb-3) Studs, Alloy 20 (Carpenter 20Cb-3) Threaded Rods — from certified bar stock per ASTM with full EN 10204 MTC 3.1/3.2 documentation and fast Mumbai dispatch.
Alloy 20 (Carpenter 20Cb-3) Bolts
Alloy 20 (Carpenter 20Cb-3) Screws
Alloy 20 (Carpenter 20Cb-3) Washers
Alloy 20 (Carpenter 20Cb-3) Studs
Alloy 20 (Carpenter 20Cb-3) Threaded Rods

Technical Data

Alloy 20 (Carpenter 20Cb-3) Nuts Dimensions, Sizes & Thread Standards

Alloy 20 (Carpenter 20Cb-3) Nuts are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 934 (hex nut) / ISO 4032 / ASME B18.2.2. Custom thread pitches and heavy hex available. Inch and metric sizes supplied per order.

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
M726.010558.0
M806.011564.0
M1006.014580.0

Dimensional & Material Standards

StandardCoversThread
DIN 934Hex nutsMetric
ISO 4032Hex nutsMetric
ASME B18.2.2Hex & heavy hex nutsUNC/UNF
DIN 439Thin nutsMetric
ISO 4035Thin nutsMetric
DIN 985Lock nutsMetric
ASME B18.16.6Prevailing torque nutsUNC/UNF
Material StandardRequirement
ASTM B473Bar/rod - UNS N08020
ASTM F594Fastener mechanical
NACE MR0175Sour service =241 HB
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

Alloy 20 Chemical Composition

Alloy 20 (Carpenter 20Cb-3) Nuts (UNS N08020) are produced from a niobium-stabilized alloy containing nickel (32–38%), chromium (19–21%), molybdenum (2–3%), and copper (3–4%) per ASTM. Niobium stabilization at 8× minimum carbon content prevents intergranular corrosion in weld zones; the Mo + Cu combination delivers sulfuric acid immunity at all concentrations.

Chemical Composition per ASTM B473

ElementComposition (%)
Nickel (Ni)32.0-38.0%
Chromium (Cr)19.0-21.0%
Iron (Fe)Balance
Copper (Cu)3.0-4.0%
Molybdenum (Mo)2.0-3.0%
Manganese (Mn)2.0% max
Silicon (Si)1.0% max
Carbon (C)0.07% max
Niobium (Nb) + Ta8xC min, 1.0% max
Phosphorus (P)0.045% max
Sulfur (S)0.035% max
? All heats verified by NABL-accredited spectrometry. PMI and intergranular corrosion test available on request.

Why Alloy 20 (Carpenter 20Cb-3) Alloy Composition Matters for Nuts

Cu (3–4%) — Sulfuric Acid Resistance
Copper enhances Alloy 20’s resistance to sulfuric acid, making these nuts the industry standard for acid piping and vessel connections in chemical plants.
Nb Stabilization — Intergranular Corrosion Protection
Niobium (columbium) prevents sensitization and intergranular attack, ensuring Alloy 20 nuts maintain integrity after welding or high-temperature service.
Cr + Mo — Pitting & Chloride SCC Resistance
Chromium and molybdenum provide robust resistance to pitting, crevice corrosion, and chloride-induced stress corrosion cracking, outperforming 316L in aggressive environments.

Fastener Performance

Alloy 20 (Carpenter 20Cb-3) Nuts Mechanical Properties & Torque Reference

The table below lists mechanical properties and torque reference for Alloy 20 (Carpenter 20Cb-3) Nuts per ASTM. Alloy 20 (Carpenter 20Cb-3) 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)
M127032
M1617065
M20340105
M24590150
M301200245
M362100355
M423300480
M484800630
?? Anti-galling: Use molybdenum-based or nickel-based anti-seize. Lubricated values assume K=0.15. Avoid copper-based anti-seize in acid service.

Industry Applications

Alloy 20 (Carpenter 20Cb-3) Nuts Applications — Industries & End Uses

Alloy 20 (Carpenter 20Cb-3) Nuts from RealBolt are specified across sulfuric acid plants, fertilizer production, and pharmaceutical where very good corrosion resistance and 620 MPa tensile strength are required for reliable fastener performance. Click each industry below for detailed application examples.
Alloy 20 nuts are the industry standard for bolted joints in sulfuric acid piping, acid storage tanks, and reactor vessels. Their superior resistance to sulfuric acid and chloride stress corrosion cracking ensures long-term reliability in acid plant environments.
Used in process equipment, heat exchangers, and piping systems where resistance to organic acids, chlorides, and cleaning chemicals is critical. Alloy 20 nuts meet FDA and ASME BPE requirements for hygienic and corrosion-resistant fasteners.
Alloy 20 nuts are specified for brine heaters, evaporators, and high-chloride water systems where pitting and crevice corrosion are a concern. Their performance exceeds 316L in aggressive chloride environments.
Used in urea reactors, phosphoric acid production, and fertilizer handling equipment. Alloy 20 nuts provide reliable service in mixed acid and chloride-rich process streams.

Alloy 20 (Carpenter 20Cb-3) Nuts Standards & International Certifications

Alloy 20 (Carpenter 20Cb-3) 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 3.1/3.2, PMI (XRF), NACE MR0175/ISO 15156, and NABL-accredited lab reports — available on request for all orders.
Standards
DIN 934 ISO 4032 ASME B18.2.2 IS 1364 IS 1367
Certifications
ISO 9001:2015NACE MR0175NABL LabPED 2014/68/EUMTC 3.1 / 3.2

Buy Alloy 20 (Carpenter 20Cb-3) Nuts from India's Leading Manufacturer — Get a Competitive Quote Today

Partner with RealBolt — India’s leading manufacturer of certified Alloy 20 (Carpenter 20Cb-3) 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.
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Answers for Buyers

Alloy 20 (Carpenter 20Cb-3) Nuts — Frequently Asked Questions

Browse expert answers to common questions about Alloy 20 (Carpenter 20Cb-3) Nuts from RealBolt — covering ASTM B473, sulfuric acid resistance, niobium stabilization, available sizes, and EN 10204 3.1 documentation. Contact our technical team directly for project-specific guidance on Alloy 20 (Carpenter 20Cb-3) nuts selection and pricing.
Alloy 20 nuts are available to DIN 934 (hex nut), ISO 4032, ASME B18.2.2 (inch hex and heavy hex), DIN 439 (thin nut), and DIN 985 (lock nut). Custom prevailing torque and slotted nuts can be supplied on request. Both metric and UNC/UNF threads are available.
Molybdenum-based or nickel-based anti-seize is recommended for Alloy 20 nuts, especially in acid or chloride environments. Avoid copper-based anti-seize, as copper can accelerate corrosion in sulfuric acid. Apply anti-seize to threads and nut faces to prevent galling and ensure accurate torque.
Yes – Alloy 20 is specifically engineered for sulfuric acid resistance and offers superior performance in chloride-rich and acidic environments compared to 316L. Its copper and niobium content prevent pitting, crevice corrosion, and stress corrosion cracking, making it ideal for chemical processing and water treatment plants.
No formal MOQ for standard sizes (M8-M36) held ex-stock – we supply from single pieces for urgent maintenance. Custom sizes or special thread forms have an MOQ of 10 kg. 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