RapidBoltGet a Quote
    Back to Products

    Heavy Hex Nuts & Washers for Flange Bolting

    Heavy hex nuts, washers, and fastener accessories manufactured to ASTM A194 specifications in all grades to complement our bolt and stud range.

    Industrial nuts and washers for engineered fastening systems
    Heavy hex nuts and flat washers for pressure system assemblies
    EN 10204 3.1 Certified
    ISO 9001 Quality
    PTFE coated ASTM A194 2H heavy hex nuts packed with sleeved ASTM A193 B7 stud bolts
    Coated A194 2H heavy hex nuts supplied as matched kits with A193 B7 studs

    Overview

    Our nuts and washers complement the full range of stud bolts and hex bolts, ensuring matched material grades and specifications for complete bolted assemblies. We supply heavy hex nuts to ASTM A194 in all standard grades, along with hardened washers, spring washers, and specialty washer types. All components are supplied with EN 10204 3.1 certification and can be matched to specific bolt batches for full assembly traceability.

    EMG supplies ASTM A194 heavy hex nuts in 50+ material grades — including 2H, 8M, and exotic alloys like Inconel 625 and Hastelloy C-276 — all matched by heat number to companion bolts.

    Typical Applications

    • Companion nuts for ASTM A193 stud bolts
    • Flange joint assemblies in pressure piping
    • Structural steel connections requiring matched fasteners
    • Pressure vessel and heat exchanger closures
    • High-temperature service in power generation
    • Corrosive environment applications requiring exotic alloys

    Fastener Types We Supply

    • Heavy hex nuts to ASTM A194 (2H, 2HM, 4, 7, 8, 8M grades)
    • Finished hex nuts to ASTM A563
    • Hardened flat washers to ASTM F436
    • Through-hardened washers for high-strength bolting
    • Spring lock washers and wedge-locking washer pairs for vibration-critical joints
    • Custom nuts and washers to project specifications

    Common Materials & Grades

    ASTM A194 2HASTM A194 2HMASTM A194 3ASTM A194 4ASTM A194 6ASTM A194 7ASTM A194 7MASTM A194 8ASTM A194 8MASTM A194 8CASTM A194 8TASTM A194 8MLCuNASTM A194 43Duplex 2205Super Duplex 2507Inconel 625Monel 400Hastelloy C-276

    Standards & Documentation

    • EN 10204 3.1 Mill Test Reports with chemical and mechanical certification
    • Heat number traceability matched to companion bolts when required
    • Proof load testing per ASTM A194 requirements
    • Dimensional inspection to ASME B18.2.2 / ISO 4032
    • ISO 9001:2015 certified quality management

    NEED MACHINED COMPONENTS TOO?

    Spacers, blinds, special nuts, shafts and bushes — supplied to your drawing with the same traceability as your bolting. Precision Machined Components →

    RELATED RESOURCES

    Stud BoltsHex BoltsWedge-Locking WashersASME PCC-1 Through-Hardened WashersCoated FastenersASTM StandardsAPI 20E & 20F BoltingNORSOK M-650
    FREQUENTLY ASKED QUESTIONS

    Technical FAQs

    Which ASTM A194 nut grade pairs with A193 B7 stud bolts?

    +
    ASTM A194 Grade 2H is the standard companion nut for A193 B7 stud bolts. For sour service (NACE MR0175), A194 Grade 2HM is used with A193 B7M studs. For high-temperature service above 450°C, A194 Grade 4 or 7 nuts are specified to match A193 B16 studs.

    What is the difference between ASTM A194 and A563 nuts?

    +
    ASTM A194 nuts are designed for high-pressure and high-temperature service, with mandatory proof load testing and material certification. ASTM A563 nuts are general-purpose nuts for structural and mechanical applications. For safety-critical flanged connections in oil & gas and petrochemical industries, A194 nuts are required.

    Can nuts and washers be heat-number matched to specific bolt batches?

    +
    Yes. We routinely supply nuts and washers heat-number matched to companion bolts for complete assembly traceability. This is standard practice for critical pressure-retaining connections and is documented in consolidated EN 10204 3.1 certificates covering the entire bolting set.

    What nut grades are suitable for cryogenic LNG service?

    +
    For cryogenic service below -46°C, ASTM A194 Grade 4 (carbon-moly) or Grade 7 (AISI 4140) nuts are specified. These grades are Charpy impact tested to demonstrate adequate toughness at low temperatures, making them suitable for LNG plant piping and cryogenic storage systems.
    GET IN TOUCH

    Need a Quote for Nuts & Washers?

    Send us the size, grade and quantity — or your drawings and bill of materials — and we'll return a technical quote for nuts & washers with lead times and certification included.

    Request a Nuts & Washers QuoteCall Now

    Emergency Support

    24/7 availability for critical projects