Aug 20, 2026News & Insights
Transport Chain: The Complete Guide to Grade 70 and Heavy-Duty Cargo Securing
This guide explains what transport chain is, which grades and standards apply, how to select the right chain for the load, and how to use it correctly
When cargo shifts on a flatbed trailer, the results can be catastrophic — lost loads, damaged goods, and serious road accidents. This is why transport chain, also known as binding chain or tie-down chain, is one of the most safety-critical components in the trucking and logistics industry.

What Is Transport Chain?
Transport chain is a welded steel chain designed specifically for securing cargo during transport. It is used with load binders and hooks to tie down heavy equipment, building materials, logs, steel coils, and machinery on flatbed trailers, rail cars, and ships.
Unlike lifting chain, which is designed for vertical hoisting, transport chain is built to withstand static tension and dynamic shock loads caused by vehicle movement, braking, and road vibration.
Material: Carbon Steel vs. Alloy Steel
The material of a transport chain determines its strength grade, durability, and suitability for different applications. Two broad categories are used:
Material | Common Grades | Characteristics | Typical Use |
|---|---|---|---|
Carbon Steel<br>(Q195, Q235, 20Mn2) | Grade 30, Grade 43, Grade 70 | Cost-effective, moderate to high strength after heat treatment, weldable and widely available | Grade 70 is the standard for truck tie-down in North America |
Alloy Steel<br>(20CrMnTi, 25MnV) | Grade 80, Grade 100 | Higher strength-to-weight ratio, excellent impact and wear resistance, quenched and tempered | Heavy-duty cargo securing and lifting applications requiring maximum safety margin |
Key distinction:
- Grade 70 is typically a carbon steel chain. It is engineered for tie-down and cargo securement, not for overhead lifting.
- Grade 80 and Grade 100 are alloy steel chains. They can be used for heavy lashing and, where certified to EN 818-2, for lifting operations.
Common Grades of Transport Chain
The grade of a chain indicates its strength. The higher the grade, the greater the breaking strength for the same diameter.
Grade | Material | Typical Use | Standard |
|---|---|---|---|
Grade 30 | Carbon steel | Light-duty, general securing | Proof coil chain |
Grade 43 | Carbon steel | Medium-duty tie-down | High test chain |
Grade 70 | Carbon steel | Heavy-duty truck and trailer securing — the industry standard | Transport chain, NACM specification |
Grade 80 | Alloy steel | Heavier loads, some overlap with lifting | Alloy chain |
Grade 100 | Alloy steel | Extreme heavy-duty securing, high strength-to-weight ratio | Alloy chain |
Grade 70 is the most widely used transport chain in North America. It offers an excellent balance of strength, weight, and cost, and is recognised by the U.S. Department of Transportation (DOT) for cargo securement.
Grade 70 Transport Chain Specifications
Grade 70 chain is manufactured from heat-treated carbon steel and is identifiable by its golden yellow chromate finish, which helps distinguish it from lower grades. Key diameters and working load limits (WLL) per NACM guidelines:
Diameter (inch) | Diameter (mm) | Working Load Limit (lbs) | Breaking Strength (lbs) |
|---|---|---|---|
1/4" | 7 mm | 3,150 | 12,600 |
5/16" | 8 mm | 4,700 | 18,800 |
3/8" | 10 mm | 6,600 | 26,400 |
1/2" | 13 mm | 11,300 | 45,200 |
5/8" | 16 mm | 15,800 | 63,200 |
The safety factor for Grade 70 transport chain is typically 4:1 — working load limit is one-quarter of the minimum breaking strength.
Standards and Regulations
North America
In the United States and Canada, transport chain must meet the NACM Welded Steel Chain Specifications. The Federal Motor Carrier Safety Administration (FMCSA) cargo securement rules require that tie-down assemblies be rated and marked with their WLL.
Grade 70 chain is typically marked every few links with the grade (7, 70, or G70) and the manufacturer's symbol.
Europe
In the EU, lashing chains fall under EN 12195-3, which specifies safety requirements for chain lashing systems. Chains must be CE marked and supplied with documentation of their lashing capacity (LC).
How to Select the Right Transport Chain
Step 1: Calculate the Required Working Load
The combined WLL of all tie-downs must be at least 50% of the cargo weight to prevent forward movement, and 50% for rear and lateral movement (FMCSA rule). In practice, many operators use more chains than the minimum for safety.
Step 2: Choose the Correct Diameter and Grade
Match the chain diameter to the required WLL. Grade 70 3/8" is the most common size for general flatbed work, while 1/2" is used for heavy machinery and construction equipment.
Step 3: Select Matching Components
Every part of the tie-down system must be rated to the same WLL as the chain. This includes:
- Grab hooks — for connecting to anchor points
- Clevis hooks — for larger attachment points
- Load binders — lever or ratchet type, used to tension the chain
- Connecting links — for joining chain sections
Mixing a Grade 70 chain with a Grade 30 hook is dangerous and illegal in many jurisdictions.
Step 4: Check for Markings
All components should carry legible grade markings and WLL ratings. If the markings are worn away, retire the chain.
Safety and Maintenance
Transport chain operates under high tension. Proper use and inspection are essential.
Practice | Frequency |
|---|---|
Inspect for stretched, bent, or cracked links | Before each use |
Check hooks for wear or deformation | Before each use |
Replace chain if elongation exceeds 5% or link wear exceeds 10% | Regular intervals |
Lubricate binder threads | As needed |
Store indoors when not in use | Always |
Critical safety note: Never use transport chain for overhead lifting unless it is specifically rated and certified for that purpose. Grade 70 chain is for tie-down only — lifting requires Grade 80 or Grade 100 alloy chain under EN 818-2.
Transport Chain vs. Lifting Chain
Feature | Transport Chain (Grade 70) | Lifting Chain (Grade 80/100) |
|---|---|---|
Material | Carbon steel | Alloy steel |
Purpose | Cargo tie-down | Overhead lifting |
Standard | NACM / EN 12195-3 | EN 818-2 |
Safety factor | 4:1 | 4:1 (G80), higher for some applications |
Finish | Golden yellow zinc | Painted, galvanized, or black |
Flexibility | Moderate | Moderate to high |
Marking | G70 | G80, G100 |
Boyuan Metal Supply Capability
Boyuan Metal supplies transport chain in carbon steel (Grade 70) and alloy steel (Grade 80/100) , with the following options:
- Diameters from 6 mm to 16 mm
- Surface finishes: yellow chromate, electro-galvanized, hot-dip galvanized
- Matching hardware: grab hooks, clevis hooks, ratchet load binders, connecting links
- Custom lengths, packaging, and branding
- Mill test certificates with every shipment
Whether you distribute tie-down systems or secure your own fleet, we can deliver the right chain at competitive factory-direct pricing. Contact us to discuss your requirements or request a sample.