Grade 80 Short Link Fishing Chain | 7-20 mm Heat-Treated Alloy Steel Trawl Chain

Product Specification

Grade 80 Short Link Fishing Chain | 7-20 mm Heat-Treated Alloy Steel Trawl Chain

Product Overview

Grade 80 short link fishing chain is a compact welded alloy-steel chain supplied for commercial fishing and trawl gear assemblies where controlled link geometry, high minimum breaking force, wear resistance, and reliable connection with compatible fishing gear are required. The listed sizes use a short pitch of approximately three times the bar diameter, helping to keep the chain compact and reduce excessive link movement within the fishing gear arrangement.

This page covers the verified 7 × 21 mm to 20 × 60 mm range in the supplied parameter table. Selection should be based on chain diameter, pitch, inside and outside width, mass per metre, minimum breaking force, required finished length, end connections, fishing duty, and corrosion exposure. Grade 80 fishing chain should not be described as a certified lifting chain, anchor chain, or mooring chain unless a separate applicable standard, proof-test programme, marking system, and certificate scope have been agreed.

Quick Specifications

• Product type: Welded short link fishing chain → compact chain geometry for commercial fishing and trawl gear assemblies.
• Listed size range: 7 × 21 to 20 × 60 mm → six verified sizes with nominal bar diameters from 7 to 20 mm.
• Material: Heat-treated alloy steel → material grade, chemical composition, heat-treatment condition, and hardness range are to be confirmed.
• Minimum breaking force: 53 to 440 kN → batch selection value for new straight chain tested in direct tension; it is not the permitted service load.
• Mass per metre: 1.09 to 8.85 kg/m → useful for calculating gear weight, handling load, shipping mass, and total chain quantity.
• Short-link geometry: Pitch approximately 3d → supports compact routing and compatibility with specified shackles, swivels, rings, or fishing-gear fittings.
• Surface finish: Bare, blackened, painted, or other approved coating → marine exposure, abrasion, coating thickness, and dimensional fit must be considered.
• Supply basis: Cut lengths, continuous lengths, end fittings, marking, test documentation, and third-party inspection according to the confirmed order scope.

Main Technical Parameters

Chain Geometry & Connection Fit

• The nominal size is expressed as bar diameter d × pitch p. All six listed sizes use p = 3d, which is the defining compact geometry used on this page.
• Inside width controls whether shackles, rings, swivels, hooks, connectors, or other fishing-gear components can enter and articulate without binding.
• Outside width affects clearance through guides, pockets, chain boxes, rollers, net gear, and other surrounding equipment.
• Compatible fittings should be selected by actual pin diameter, jaw width, articulation requirement, and load rating rather than by nominal chain diameter alone.
• The chain should not be twisted, side-loaded across a link, sharply bent over an unsuitable radius, or connected through an undersized fitting.
• If the chain is required to pass through a pocket wheel, gypsy, calibrated drive, or special guide, the dimensional tolerance and calibration requirement must be confirmed separately.

Fishing Duty, Wear & Service Life

• Commercial fishing chain is exposed to repeated movement, impact, abrasion, salt water, deck contact, and contamination from fishing operations. Selection should account for the actual duty rather than minimum breaking force alone.
• Short links provide a compact and relatively stable chain form, but wear can concentrate at interlink contact zones and at connection points with shackles, rings, swivels, or net fittings.
• The design should avoid continuous rubbing over sharp steel edges, excessive shock loading, severe twisting, and unbalanced loading between parallel chain legs.
• Inspection intervals should reflect operating hours, catch cycle, seabed contact, corrosion exposure, and observed wear. Elongated, cracked, bent, deeply corroded, or locally worn links should be removed from service.
• Retirement criteria, allowable diameter loss, elongation limit, and repair policy must follow the purchaser’s fishing-gear procedure or the agreed product standard. Damaged heat-treated chain should not be field-welded without an approved manufacturer procedure.
• Chain lost at sea can become abandoned fishing gear. Finished lengths, connection security, marking, inspection, and recovery procedures should be coordinated with the vessel operator’s gear-management practices.

Material, Welding & Heat Treatment

• Alloy-steel bar provides the strength and toughness basis for Grade 80 performance, but the exact steel chemistry and cleanliness requirement must be stated in the purchase specification.
• Each link is formed and electrically welded before final heat treatment in typical Grade 80 chain production. The actual process route and equipment qualification should be confirmed with the supplier.
• Quenching and tempering are commonly used for Grade 80 alloy chain to obtain the required balance of strength, toughness, ductility, and wear resistance.
• Weld-zone quality is critical because the link weld forms part of the direct tensile load path. Process control, visual inspection, dimensional checks, and mechanical testing should cover both base material and welded links.
• The term “heat resistant” should not be used as a general service claim. Maximum and minimum operating temperatures and any load reduction after heat exposure require confirmation against the governing product standard.
• Field heating, flame cutting, uncontrolled welding, or hot straightening can change the heat-treated properties and should not be carried out without written technical approval.

Surface Protection for Marine Fishing Service

• Bare or polished chain preserves the original link dimensions but provides limited corrosion protection and therefore requires appropriate storage, maintenance, and inspection.
• Blackened or painted finishes provide economical temporary protection and easy visual identification, although abrasion at interlink contact points will progressively remove the coating.
• Sprayed coating can be discussed when the coating system, dry-film thickness, flexibility, impact resistance, and effect on connection clearances are defined.
• Hot-dip galvanizing and electroplating are not presented as standard Grade 80 finishes on this page. Heat-treated alloy chain can be affected by pickling, plating, galvanizing temperature, or hydrogen-related degradation.
• Any galvanized or plated Grade 80 fishing chain requires a manufacturer-approved process, dimensional review, post-treatment verification, and confirmation that the declared breaking-force values remain valid.
• The selected finish should be stated with colour, preparation grade, coating thickness, repair method, packaging protection, and any uncoated contact or identification areas.

Quality Control & Test Documentation

• Incoming material control may include steel grade verification, heat / batch identification, chemical composition, and material certificate review.
• Production control should cover bar diameter, pitch, inside width, outside width, link shape, weld position, surface condition, and finished length.
• Heat-treatment records and hardness checks can be included where required to demonstrate process consistency.
• Proof testing, sample breaking-force testing, bend testing, elongation measurement, fatigue testing, or metallographic examination should be specified by the purchaser or governing product standard.
• The supplied minimum breaking force is a destructive test value, not an operating test load. Test method, sample quantity, test frequency, and acceptance criteria must be agreed before quotation.
• Documentation can include maker’s certificate, material certificate, dimensional inspection report, batch test report, heat-treatment record, and third-party witness report according to order.

Selection & Inquiry Guide

Step 1: Confirm the application position within the fishing gear, such as trawl rigging, net gear connection, weighting arrangement, deck-handling assembly, or another drawing-defined duty.

Step 2: Confirm nominal size d × p, required finished length, quantity, chain mass, minimum breaking force, and the project safety or design factor.

Step 3: Provide all mating fittings and clearances: shackle pin diameter, jaw width, ring or swivel dimensions, connector grade, and any guide, roller, pocket wheel, or stowage limitation.

Step 4: Confirm material grade, heat treatment, operating temperature, corrosion environment, required surface finish, colour, coating thickness, and packaging.

Step 5: Confirm testing and documentation: material certificate, proof test, batch break test, fatigue test, dimensional report, third-party inspection, marking, and traceability.

Step 6: Provide fishing-vessel type, gear drawing, photos, required delivery length, end fittings, destination, delivery time, and whether the chain is for new gear or replacement of an existing chain.

Custom Attributes

• Chain Type: Short link welded fishing chain → this page covers compact 3d-pitch geometry only.
• Grade: 80 → exact governing standard, alloy-steel specification, and mechanical-property requirements are to be confirmed.
• Nominal Sizes: 7 × 21 / 10 × 30 / 13 × 39 / 16 × 48 / 19 × 57 / 20 × 60 mm → select by load, gear weight, and fitting compatibility.
• Minimum Breaking Force: 53-440 kN → applies to new chain under the agreed direct-tension test; not a service load or lifting WLL.
• Safety / Design Factor: Minimum 4 stated by the supplier → final permissible operating load must be established by the fishing-gear designer and approved operating procedure.
• Surface Finish: Bare / blackened / painted / approved custom coating → galvanizing or plating requires separate technical confirmation.
• Length & End Fittings: To order → provide cut length, number of pieces, end-link arrangement, connectors, and allowable length tolerance.
• Documentation: According to purchase specification → supplier QMS certificate, product test reports, and third-party inspection are separate documents.

How It Works

Fishing-gear load enters through a compatible connector → Compact short links transmit direct tensile force through the welded alloy-steel chain → Chain mass and geometry contribute to the specified gear arrangement → End connection transfers the load into the next fishing-gear component

Applications

Commercial fishing gear | Trawl gear assemblies | Net rigging and weighting positions | Fishing-vessel deck gear connections | Aquaculture equipment where approved by the system designer | Replacement chain matched to an existing drawing

Certifications & Documentation

ISO 9001 certification relates to the supplier’s quality management system and is not by itself a product certificate. CE documentation applies only when the chain is placed on the EU market within the scope of applicable legislation and has completed the required conformity assessment. SGS or another third party can perform inspection or testing when included in the purchase order. Certificate type, standard, test scope, marking, and issuing organization must be confirmed before quotation.

Available documentation according to order: Supplier ISO 9001 QMS certificate | Material certificate | Maker’s certificate | Batch dimensional and breaking-force report | Heat-treatment record | Third-party inspection or SGS test report | CE declaration and supporting documents only where legally applicable

Drawing & Photos

FAQ

Q1: How should the correct Grade 80 fishing-chain size be selected?

A1: Select the chain from the required fishing-gear load, project design factor, minimum breaking force, required chain weight, link dimensions, finished length, and compatibility with every connector and guide. Do not select by diameter alone, and do not treat minimum breaking force as the permitted operating load.

Q2: Is this chain suitable for overhead lifting?

A2: Not automatically. This page is for commercial fishing chain. Use for lifting requires a separately confirmed lifting-chain standard, certified working load limit, proof-test regime, marking, traceability, compatible lifting components, and applicable CE or regulatory documentation. The supplied fishing-chain table alone does not establish lifting compliance.

Q3: Can Grade 80 fishing chain be hot-dip galvanized or electro-galvanized?

A3: Only after technical confirmation by the chain manufacturer. Pickling, plating, and galvanizing can affect heat-treated alloy steel and may change dimensions or mechanical performance. The process, hydrogen-control measures, post-treatment testing, and continued validity of the minimum breaking force must be confirmed before supply.