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Rivets · BS 7805 Part 2:1997

A4 (316) Stainless Steel Huck C50L Large-Diameter Lockbolt Assembly

Mechanical properties, corrosion behaviour and the full dimensional range for this grade.

A4 Stainless Steel Huck C50L Large-Diameter Lockbolt Assembly are supplied to ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80. Corrosion behaviour is superior, including marine and chloride environments, the material is largely non-magnetic, and the usable service range is approx. -200 °C to +400 °C, subject to the property class and the joint. In practice this grade is specified for marine, coastal and chemical applications.

Grade
ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Corrosion resistance
Superior, including marine and chloride environments
Magnetic response
Largely non-magnetic
Service temperature
approx. -200 °C to +400 °C, subject to the property class and the joint

Property values are typical for the grade. Certified mechanical test data is available on request for production orders.

A4 (316) Stainless Steel Huck C50L Large-Diameter Lockbolt Assembly reference image

Huck C50L Large-Diameter Lockbolt Assembly manufactured in A4 Stainless Steel (ISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80) are dimensioned to BS 7805 Part 2:1997. The sections below give the mechanical and physical properties of the grade, its behavior in corrosive and elevated-temperature service, and the full size table.

Why Choose A4 Stainless Steel for Huck C50L Large-Diameter Lockbolt Assembly

Specified for marine, coastal and chemical applications. For huck c50l large-diameter lockbolt assembly, this matters when superior, including marine and chloride environments is the primary requirement.

Mechanical & Physical Properties

Grade designationISO 3506 group A4 (316 / 1.4401), commonly supplied A4-80
Magnetic responseLargely non-magnetic
Service temperatureapprox. -200 °C to +400 °C, subject to the property class and the joint
Corrosion characteristicSuperior, including marine and chloride environments

Corrosion Behavior in Service

A4 (316) adds 2–3% molybdenum to the A2 (304) composition, which dramatically improves resistance to chloride-pitting corrosion. For Huck C50L Large-Diameter Lockbolt Assembly in marine, coastal, swimming-pool or food-processing environments, A4 is the default selection.

Comparable Grades

For Huck C50L Large-Diameter Lockbolt Assembly, the alternative stainless grade is A2 (304). A2 (304) suits general indoor and outdoor service; A4 (316) adds molybdenum for marine and chloride environments. Where higher strength matters more than corrosion, switch to plated alloy-steel class 8.8 or 10.9.

Using Stainless Fasteners in Aluminum

Stainless steel is more noble than aluminum, so in the presence of an electrolyte — rain, condensation, salt spray — the aluminum becomes the anode and corrodes at the joint. The effect is driven by the area ratio: a small stainless fastener in a large aluminum section is normally acceptable, while a large stainless fastener in thin aluminum is not. Where the joint is wet, isolate the two metals with a coated or nylon washer and a sealant, or specify an aluminum or coated fastener instead.

Sizes of Huck C50L Large-Diameter Lockbolt Assembly Available in A4 Stainless Steel

Nominal diameter (mm)Pin head stylesCollar stylesStrength gradeAssemblyMaterial optionsReference standard
12.7round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
15.9round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
19.1round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
22.2round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
25.4round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
28.6round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
31.8round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
34.9round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997

Technical Drawing

Customize the parameters below — every spec field is editable, and the drawing redraws to match the values you choose. Changing the size will snap the other fields to that size's standard values; you can then override any individual value.

Sends the selected values to the quote form below.

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The form below follows the current technical drawing configuration. Change the drawing values above and the request details update automatically.

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Specification
Business Information

Dimensions & Specifications (BS 7805 Part 2:1997)

Nominal diameter (mm)Pin head stylesCollar stylesStrength gradeAssemblyMaterial optionsReference standard
12.7round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
15.9round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
19.1round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
22.2round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
25.4round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
28.6round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
31.8round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997
34.9round / truss / countersunk / threaded-headstandard / flanged / low-profile8.8pin + collarsteel / stainless steel / aluminum alloyBS 7805 Part 2:1997

Applications & Industries

The sectors that buy Huck C50L Large-Diameter Lockbolt Assembly to BS 7805 Part 2:1997, and the duty each one buys them for. Stocked from 12.7 to 34.9 (nominal diameter).

Industries that specify Huck C50L Large-Diameter Lockbolt Assembly

  • Earthmoving equipment Bucket, boom and chassis structures subject to shock and vibration.
  • Rail vehicles High-cycle structural assemblies that need a swaged mechanical lock.
  • Steel plant fabrication Thick-section one-side joints using large pin and collar combinations.
  • Heavy truck frames Large-diameter structural joints in rails, crossmembers and chassis sections.
  • Transport & bodywork Trailer, bus and van panels joined blind from one side.
  • Signage & cladding Fast, vibration-resistant fixing of thin material.

Typical applications

  • selecting a round, truss, countersunk or threaded-head pin form
  • matching the collar profile to the joint access and bearing surface
  • building permanent connections where a large removable bolt is impractical
  • forming a large-diameter structural pin-and-collar joint
  • riveted pivots that must stay tight but still turn
  • permanent joints in thin sheet where a threaded fastener would loosen

Service conditions to specify against

Marine and coastal
Available in A4 (316) stainless for chloride exposure — coastal structures, pool halls, water treatment and deck hardware, where A2 will eventually pit.
Vibration
Specified where cyclic load would loosen a plain nut or screw — rotating plant, rail, mobile equipment and anything that is not re-torqued in service.

Where to use something else

  • Do not treat the swaged collar as a conventional nut if the joint must be removed without cutting.
  • Not for a joint that has to come apart in service — removal means drilling the rivet out.

Full application guide: where Huck C50L Large-Diameter Lockbolt Assembly are used, how to specify them, and the cases they are wrong for

Inside the plant

Manufactured in our own plant

This part is cold-formed, threaded, heat-treated and finished in-house. The stages below are where its class and finish are actually decided.

  1. Wire rod feeding into a cold heading machine
    01

    Cold heading

    Wire rod is drawn to size and cold-formed into blanks. Forming rather than cutting keeps the grain flow continuous around the head, which is where a bolt is most likely to fail.

    Head dimensions and under-head radius checked at set-up and per shift.

  2. Thread rolling machine producing bolt threads
    02

    Thread rolling

    Threads are rolled between hardened dies rather than cut. Rolled threads are stronger in fatigue than cut threads and hold pitch and flank angle far more consistently across a batch.

    Go / no-go ring gauges to ISO 965 tolerance class 6g.

  3. Baskets of bolts staged for heat treatment
    03

    Heat treatment

    Quench-and-temper brings carbon and alloy steel to the property class ordered — 8.8, 10.9 or 12.9 — with the furnace charge tracked so a finished lot can be traced back to it.

    Core hardness and tensile tested per lot to ISO 898-1.

  4. Zinc plated bolts in a treatment basket
    04

    Surface treatment

    Zinc, zinc-nickel, hot-dip galvanizing, black oxide, phosphate and Dacromet, selected against the service environment rather than against the price list.

    Coating thickness and neutral salt spray hours to ISO 9227.

Frequently Asked Questions

Can A4 Stainless Steel Huck C50L Large-Diameter Lockbolt Assembly gall during installation?

Yes — stainless on stainless is prone to thread galling under load, especially at smaller sizes. Use an anti-galling lubricant or wax thread compound, and slow the tightening rate where possible.

Is A4 Stainless Steel food-grade?

A4 (316) is the standard food-contact stainless grade in most jurisdictions, particularly where chloride exposure (brines, dairy CIP) is present.

Can A4 Stainless Steel Huck C50L Large-Diameter Lockbolt Assembly be used with aluminum?

Yes, but stainless drives mild galvanic corrosion of aluminum in wet service — isolate with a coating, sleeve or paint, or accept the trade-off if the joint is dry and indoor.

What's the service temperature limit for A4 Stainless Steel?

The practical service range is approx. -200 °C to +400 °C, subject to the property class and the joint.

How do I request a quotation?

Use the technical drawing on this page to pick the exact configuration, then submit it with the quote form. We respond within one business day.