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

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

Alloy 20 (Carpenter 20Cb-3) bolts are high-performance austenitic stainless steel fasteners manufactured from UNS N08020 bar stock, conforming to ASTM B473. Designed for maximum resistance to sulfuric acid and chloride-induced corrosion, Alloy 20 bolts combine nickel (32-38%), chromium (19-21%), and copper (3-4%) with niobium stabilization for superior intergranular corrosion resistance.

These bolts are widely specified in chemical processing, pharmaceutical, and food industries where standard stainless steels fail due to stress corrosion cracking or acid attack. Alloy 20 bolts are NACE MR0175 compliant for sour service and are a preferred choice for flange connections, pressure vessels, and process piping in aggressive environments.

Quick Specifications

MaterialAlloy 20 (Carpenter 20Cb-3)
UNS NumberN08020
DIN Number2.4660
Material StandardASTM B473
Bolt Standard (Metric)DIN 931 / DIN 933 / ISO 4014
Bolt Standard (Inch)ASME B18.2.1
Thread FormISO Metric / UNC / UNF
Diameter RangeM6-M100 / ¼"-4"
Tensile Strength551 MPa (80 ksi) min
Yield Strength241 MPa (35 ksi) min
HardnessMax 217 HB
? All material certified by NABL-accredited laboratory. PMI 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) Nuts, 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) Nuts
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) Bolts Dimensions, Sizes & Thread Standards

Alloy 20 (Carpenter 20Cb-3) Bolts are available in metric M6–M100 and inch ¼″–4″ as standard. Per DIN 931 (partial thread) / DIN 933 (full thread) / ISO 4014. Custom lengths in 5mm increments. Inch dimensions available per ASME B18.2.1. All Alloy 20 (Carpenter 20Cb-3) bolts dimensions conform to applicable DIN, ISO, and ASME B18 standards.

Hex Bolt Dimensions - Metric (DIN 931 / ISO 4014)

Size (M)Pitch (mm)A/F (mm)Head Ht (mm)Min L (mm)Max L (mm)
M61.0104.010200
M81.25135.312250
M101.5176.416300
M121.75197.520400
M162.02410.025500
M202.53012.530600
M243.03615.040600
M303.54618.750800
M364.05522.5601000
M424.56526.0801000
M485.07530.01001200
M565.58535.01201500
M646.09540.01402000
M726.010545.01602000
M806.011550.01802500
M1006.014563.02003000

Dimensional & Material Standards

StandardCoversThread
DIN 931Hex bolts, partial threadMetric
DIN 933Hex bolts, full threadMetric
ISO 4014Hex head screws, partialMetric
ISO 4017Hex head screws, fullMetric
ASME B18.2.1Hex & heavy hex boltsUNC/UNF
ASME B16.5Stud bolts for flangesUNC
MSS SP-75Stud bolts, high-pressureUNC
Material StandardRequirement
ASTM B473Bar/rod - UNS N08020
ASTM F468Fastener mechanical
NACE MR0175Sour service =35 HRC
EN 10204 3.1Mill test certificate
EN 10204 3.2TPI-witnessed MTC

Material Chemistry

Alloy 20 (Carpenter 20Cb-3) Chemical Composition

Alloy 20 (Carpenter 20Cb-3) Bolts (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%
Copper (Cu)3.0-4.0%
Molybdenum (Mo)2.0-3.0%
Iron (Fe)Balance
Carbon (C)0.07% max
Manganese (Mn)2.0% max
Silicon (Si)1.0% max
Niobium (Nb)8xC min-1.0% max
Phosphorus (P)0.045% max
Sulfur (S)0.035% max
? All heats verified by NABL-accredited spectrometry. PMI available on request.

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

Cu (3–4%) — Sulfuric Acid Resistance
Copper content in Alloy 20 provides exceptional resistance to sulfuric acid attack, making these bolts ideal for acid process piping and equipment flanges.
Nb Stabilization — Intergranular Corrosion Protection
Niobium stabilizes the alloy against sensitization, preventing intergranular corrosion after welding or high-temperature exposure, which is critical for bolted joints in chemical plants.
High Nickel & Chromium — Chloride SCC Resistance
The high nickel and chromium content ensures Alloy 20 bolts resist chloride-induced stress corrosion cracking, outperforming 316L in aggressive environments.

Fastener Performance

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

The table below lists mechanical properties and torque reference for Alloy 20 (Carpenter 20Cb-3) Bolts per ASTM. Alloy 20 (Carpenter 20Cb-3) bolts achieve 620 MPa tensile strength, with hardness, yield, and elongation values verified by NABL-accredited testing and reported in the EN 10204 MTC.

Bolt SizeDry (Nm)Lubricated (Nm)Clamp Load (kN)
M12655224
M1615512458
M2031024893
M24540432135
M301080864215
M3618801504312
M4230002400430
M4844503560565
?? Anti-galling: Use molybdenum-based or nickel-based anti-seize. Lubricated values assume K=0.15. Avoid copper-based anti-seize for maximum corrosion resistance.

Industry Applications

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

Alloy 20 (Carpenter 20Cb-3) Bolts 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 bolts are the industry standard for flange connections, reactor closures, and piping in sulfuric acid production and handling, where resistance to acid attack and stress corrosion cracking is critical.
Used for bolted joints in process vessels, heat exchangers, and piping systems where high purity, resistance to organic acids, and prevention of metallic contamination are required.
Flange bolts and fasteners for brine heaters, evaporators, and reverse osmosis systems, offering superior resistance to chloride pitting and crevice corrosion compared to 316L.
Alloy 20 bolts are specified for urea reactors, ammonium sulfate systems, and mixed acid process equipment where aggressive chemicals and high temperatures are present.

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

Alloy 20 (Carpenter 20Cb-3) Bolts 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 931 DIN 933 ISO 4014 ISO 4017 ASME B18.2.1 IS 1364 IS 1367
Certifications
ISO 9001:2015NACE MR0175NABL LabPED 2014/68/EUMTC 3.1 / 3.2

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

Partner with RealBolt — India’s leading manufacturer of certified Alloy 20 (Carpenter 20Cb-3) Bolts — 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) Bolts — Frequently Asked Questions

Browse expert answers to common questions about Alloy 20 (Carpenter 20Cb-3) Bolts 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) bolts selection and pricing.
Alloy 20 hex bolts are available to DIN 931 (metric partial thread), DIN 933 (metric full thread), ISO 4014/4017, and ASME B18.2.1 (inch hex and heavy hex). Stud bolts are supplied per ASME B16.5 or MSS SP-75 for flange applications. Custom thread forms (BSW, BSF, Whitworth, BSPP) can be manufactured on request with a typical 15 working day lead time.
Use molybdenum-based or nickel-based anti-seize compound (such as Molykote P-37 or Jet-Lube Pure Nickel) on Alloy 20 bolts. Apply to threads and nut bearing face to prevent galling and facilitate disassembly. Avoid copper-based anti-seize to maintain maximum corrosion resistance in acid environments.
Yes – Alloy 20 bolts are specifically engineered for sulfuric acid resistance and provide excellent performance in chloride-rich environments, including protection against pitting, crevice corrosion, and stress corrosion cracking. They are widely used in chemical, pharmaceutical, and water treatment plants for these reasons.
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 have an MOQ of 10 kg minimum. ASME B16.5 flange stud bolt sets are supplied by the set with no minimum. Quantity price breaks 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