Aug 21, 2026News & Insights

High Test Chain: The Complete Guide to Grade 43 Welded Chain

This guide explains what high test chain is, how it differs from other grades, its typical specifications, and where it is most commonly used

High test chain, also known as Grade 43 chain, is a welded steel chain that sits between proof coil chain and transport chain in terms of strength and cost. It is widely used for truck tie-downs, towing, logging, and general industrial securing where more strength is needed than Grade 30 can provide, but where the higher cost of Grade 70 is not justified.

What Is High Test Chain?

High test chain is a welded chain manufactured from alloy steel. It is classified as Grade 43, meaning it has a minimum breaking stress of approximately 430 N/mm² — about 43% higher than Grade 30 proof coil chain.

The term "high test" reflects the chain's higher strength compared with standard proof coil chain. It is designed for cargo securement and general utility, not for overhead lifting.

Material and Manufacturing

High test chain is produced from medium-carbon steel wire, typically equivalent to higher-carbon grades than those used for proof coil chain. The manufacturing process is similar to other welded chains:

Wire drawing — steel rod is drawn to the required diameter

Link forming — wire is bent into interlocking links

Welding — each link is electric-welded at the joint

Proof testing — the chain is proof-load tested to verify weld integrity

Surface finishing — electro-galvanized, hot-dip galvanized, or self-colored

Unlike Grade 70 transport chain, Grade 43 high test chain is generally not heat-treated after welding. Its higher strength compared with Grade 30 comes primarily from the use of a higher-carbon steel.

Surface Finishes

High test chain is available in several finishes depending on the environment and application:

Finish	Characteristics	Typical Use
Self-colored (raw)	Natural steel with light oil coating	Indoor use, budget-conscious
Electro-galvanized	Bright silver, moderate corrosion resistance	General outdoor, hardware retail
Hot-dip galvanized	Matte grey, thick zinc layer (50–80 μm)	Agricultural, outdoor, wet environments

For most tie-down and outdoor applications, electro-galvanized is the standard. For long-term outdoor or agricultural use, hot-dip galvanized provides better protection.

Grade 43 High Test Chain Specifications

Typical working load limits and breaking strengths for standard high test chain:

Diameter (inch)	Diameter (mm)	Working Load Limit (lbs)	Breaking Strength (lbs)
1/4"	6 mm	2,600	10,400
5/16"	8 mm	3,900	15,600
3/8"	10 mm	5,400	21,600
1/2"	13 mm	9,200	36,800
5/8"	16 mm	13,000	52,000

These values are approximate and based on a 4:1 safety factor. Always verify exact WLL with the manufacturer's specification sheet.

Common Applications

High test chain is a general-purpose medium-duty chain. Typical uses include:

Application	Why High Test Chain Is Used
Truck and trailer tie-down	Higher strength than proof coil at a lower cost than Grade 70
Towing and recovery	Good balance of strength and weight
Logging and forestry	Durable enough for skidding and securing loads
Agricultural	Equipment securing, fence gates, general farm use
Construction	Temporary securing, barrier chains, light rigging
General industrial	Machine guards, low-stress conveyor systems

Important: High test chain is not rated for overhead lifting. Lifting applications require Grade 80 or Grade 100 alloy chain certified to EN 818-2.

Proof Coil vs. High Test vs. Transport vs. Alloy

Property	Proof Coil (Grade 30)	High Test (Grade 43)	Transport (Grade 70)	Alloy (Grade 80/100)
Material	Low-carbon steel	Medium-carbon steel	Heat-treated carbon steel	Alloy steel, quenched & tempered
Heat treatment	None	None or minimal	Yes	Yes
Approximate strength	300 N/mm²	430 N/mm²	700 N/mm²	800–1000 N/mm²
Typical use	General securing, agriculture	Medium-duty tie-down, towing	Heavy-duty cargo securement	Lifting, heavy lashing
Relative cost	Lowest	Low	Medium	High

Standards and Identification

High test chain is manufactured to several standards, most notably:

NACM Welded Steel Chain Specifications — the North American reference

ASTM A413 — specification for carbon steel chain

ISO 1835 — international standard for short-link chain (non-lifting)

Grade 43 chain is often marked with the number 43 or the letter G43 at intervals along the chain, along with the manufacturer's symbol. This marking is important for inspection and for ensuring the correct grade is used for the intended load.

How to Choose the Right High Test Chain

Step 1: Confirm the Application

General securing and light towing → Grade 43 is appropriate

Heavy flatbed cargo securement → Upgrade to Grade 70

Overhead lifting → Do not use Grade 43; use Grade 80/100

Step 2: Match the Working Load

Select a diameter whose WLL exceeds the maximum load with an appropriate safety margin. For dynamic applications such as towing, allow extra capacity for shock loads.

Step 3: Choose the Surface Finish

Indoor → self-colored

General outdoor → electro-galvanized

Wet or agricultural → hot-dip galvanized

Step 4: Select Compatible Components

Every tie-down system must use components rated to the same WLL as the chain, including hooks, binders, and connecting links. Never mix Grade 43 chain with Grade 30 fittings.

Safety and Maintenance

High test chain operates under tension and must be inspected regularly:

Check for stretched, bent, or cracked links before each use

Inspect hooks and fittings for wear

Replace chain if elongation exceeds 5% or link wear exceeds 10%

Store indoors or protected when not in use

Boyuan Metal Supply Capability

Boyuan Metal supplies high test chain in Grade 43 with diameters from 6 mm to 16 mm, available in:

Electro-galvanized, hot-dip galvanized, or self-colored finish

Short link, mid link, or long link configurations

Standard drums, pails, reels, or custom cut lengths

Custom packaging, branding, and barcoding for retail distribution

Mill test certificates with every shipment

We also supply the complete welded chain range — Grade 30 proof coil, Grade 70 transport, and Grade 80/100 alloy — allowing you to consolidate orders with one supplier.