Description

Technical Parameters

Product Overview

Designed exclusively for heavy-duty lifting mechanisms, our Grade 80 (G80) calibrated hoist chains are manufactured in strict compliance with EN 818-7 standards. Forged from high-grade alloy steel (20Mn2 / 23MnNiMoCr54) and undergoing continuous case-hardening heat treatment, these chains deliver optimal surface hardness for wear resistance alongside a ductile core for impact absorption.

Every single link is calibrated to tight dimensional tolerances (+/- 0.1 mm pitch precision) to guarantee zero-jamming performance on hoist load sheaves under dynamic operational loads.

Technical Specifications

Chain Dia. (d)	Pitch Length (p)	Inside Width (b1)	Working Load Limit (WLL)	Proof Load (2.5x WLL)	Min. Breaking Load	Pitch Tolerance	Approx. Weight
4.0 mm	12.0 mm	5.2 mm	0.50 Ton	1.25 Ton	2.0 Ton	+/- 0.10 mm	0.38 kg/m
5.0 mm	15.0 mm	6.5 mm	0.80 Ton	2.00 Ton	3.2 Ton	+/- 0.10 mm	0.58 kg/m
6.0 mm	18.0 mm	7.8 mm	1.12 Ton	2.80 Ton	4.5 Ton	+/- 0.10 mm	0.84 kg/m
7.1 mm	21.2 mm	9.3 mm	1.60 Ton	4.00 Ton	6.4 Ton	+/- 0.12 mm	1.15 kg/m
8.0 mm	24.0 mm	10.4 mm	2.00 Ton	5.00 Ton	8.0 Ton	+/- 0.12 mm	1.45 kg/m
10.0 mm	30.0 mm	13.0 mm	3.15 Ton	7.88 Ton	12.6 Ton	+/- 0.15 mm	2.25 kg/m
11.2 mm	33.6 mm	14.6 mm	4.00 Ton	10.00 Ton	16.0 Ton	+/- 0.15 mm	2.80 kg/m

Note: Data above conforms to EN 818-7 Standard Type T. For custom pitch sizes, non-standard pocket fits, or Grade 100 options, contact our engineering department for CAD drawing validation.

Heat Treatment & Mechanical Properties

Surface Hardness (Wear Resistance): Case-hardened layer reaches 500 HV to 650 HV (Type DAT), dramatically reducing pitch elongation caused by friction against the load chain wheel.

Core Ductility & Toughness: Core hardness is controlled to prevent brittle fracture under sudden shock loads or cold-weather operations down to -40 deg C.

Total Ultimate Elongation: Guaranteed >= 10% minimum breaking elongation, ensuring visible link stretching before failure as a safety alert.

Decarburization Control: Total surface decarburization depth is restricted to < 0.1 mm to prevent fatigue micro-cracking.

Key Advantages

Zero-Snagging Calibration (+/- 0.1 mm Precision)
Pitch consistency is non-negotiable for motorized and manual hoists. Every meter of our chain passes through automated tensile stretching stretch-calibration machines, forcing every link into exact dimensional uniformity. This eliminates chain jumping, abnormal noise, and premature sprocket wear.

Automated Flash-Butt Welding
Links are formed and butt-welded using computerized resistance welding systems. The weld flash is automatically deburred to match the original link wire profile, maintaining joint swelling under 0.2 mm.

Surface Finish Options Engineered for Hoists
Black Oxide (Standard): Precision coating that maintains exact link dimensions without adding thickness; ideal for high-precision hoist mechanisms.

Electro-Galvanized (Zinc Plated): Bright aesthetic finish providing moderate atmospheric corrosion resistance (>= 96 Hours Salt Spray Tested).

Electrophoretic Painting (ED / Black E-Coat): High-adhesion anti-corrosion barrier with low friction co-efficient for heavy industrial environments.

Phosphate & Oiled: Dry-lubricated finish ideal for immediate OEM assembly lines.

Strict Quality Assurance & Testing Protocol

100% Proof Load Testing: Every length of chain is subjected to a Manufacturing Proof Force equal to 2.5 x WLL to verify 100% weld integrity.

Spectrometric Raw Material Verification: Chemical analysis of 20Mn2 / 23MnNiMoCr54 alloy rods to verify Manganese, Chromium, and Molybdenum ratios.

Metallographic Microstructure Analysis: Checking depth of hardening layer and grain size under optical microscopes.

Bending & Breaking Force Test: Destructive tensile testing on sample cuts from every 200 meters of finished chain.

Traceability & Certification: Issued with EN 10204 3.1 Mill Test Certificates detailing batch heat numbers, proof load results, and chemical composition.

OEM & Custom Packaging Solutions

We support global distributors, crane service centers, and OEM hoist manufacturers with scalable supply programs:

Custom Embossing: Brand markings, Grade designation (G80), or traceability batch codes stamped every 10 to 20 links.

Pre-Cut Length Assemblies: Chains cut to exact customer-specified lengths with end-hook links pre-installed.

Export Heavy-Duty Packaging: Steel drums (200L / 400L), reinforced plywood cases, or plastic pails mounted on heat-treated ISPM-15 wooden pallets.

FAQ

Q: What is the difference between EN 818-2 G80 Chain and EN 818-7 G80 Chain?

A: EN 818-2 applies to uncalibrated chains used primarily for chain slings and general rigging. EN 818-7 applies strictly to calibrated load chains used in chain hoists. EN 818-7 requires significantly tighter pitch tolerances (+/- 0.1 mm), special case-hardening heat treatment for wear resistance, and precise link geometry to fit hoist pocket wheels.

Q: Can your G80 chains be used in electric hoists?

A: Yes. For electric chain hoists, we supply Type DAT (Case Hardened) chains compliant with EN 818-7, specifically treated to withstand higher friction speeds and high-cycle lifting frequencies.

Q: Do you provide EN 10204 3.1 Certificates with shipments?

A: Yes. An official EN 10204 3.1 Mill Test Certificate containing raw material heat numbers, proof load test verification, breaking force curves, and dimensional inspection logs is attached to every export order.

Q: What is your standard MOQ and lead time?

A: Our minimum order quantity for standard sizes is 500 meters per diameter. Standard production lead time is 15 to 20 days. Emergency replenishment stock is available for popular sizes (6 mm, 7.1 mm, 8 mm, and 10 mm).

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Grade 80 Hoist Chain