High Test Chain, also known as Grade 43 chain, is a medium carbon steel chain known for its increased strength compared to Grade 30 chain. It offers a higher working load limit for the same nominal size, making it suitable for more demanding applications where a balance of strength and cost-effectiveness is needed.

Here’s a breakdown of its key characteristics, applications, and limitations:

Key Features:

• Material: Typically made from medium carbon steel, which is heat-treated to enhance its strength and wear resistance.
• Grade Marking: Usually marked with “4,” “43,” or “430” at intervals to indicate its grade. Some manufacturers might use their own markings, like “OA43” for their logo and grade chains.
• Construction: Features welded links, similar to Grade 30 chain. It’s available in standard link. The dimension can also adjusted according to the specific requirement.
• Strength: Offers approximately 20-50% higher working load limit than Grade 30 chain for the same size.
• Finish: Available in various finishes, including:
  • Self-colored (plain steel): Offers the highest strength.
  • Zinc plated (electro-galvanized): Provides moderate corrosion resistance.
  • Hot-dip galvanized: Offers superior corrosion resistance, making it suitable for marine and outdoor applications.
  • Other coatings: Powder coating or other specialized finishes may also be available.
• Proof Test: Typically proof-tested by the manufacturer at twice the working load limit to ensure its integrity.
• Design Factor: Generally has a design factor of 3:1 (minimum breaking load to working load limit). Some sources may indicate a 4:1 factor, so it’s crucial to verify the manufacturer’s specifications.
• Not for Overhead Lifting: This is a critical limitation. Grade 43 chain is not designed or approved for overhead lifting of personnel or heavy loads where failure could cause serious injury or damage. For such applications, higher-grade alloy steel chains (like Grade 80, 100, or 120) are required.

Common Applications:

Grade 43 High Test chain is widely used in applications requiring higher strength than Grade 30, such as:

• Load Binding/Tie-Downs: Securing heavy equipment and cargo for transport, especially in the trucking industry.
• Towing: For heavy-duty towing applications.
• Logging: Securing logs (not for lifting).
• Construction: Various general-purpose uses where higher strength is beneficial.
• Agriculture: Farm equipment and general utility applications.
• Marine Applications:
  • Anchor Chain: Often used as anchor chain, especially the short link variety which is better suited for windlasses.
  • Mooring: For general mooring purposes in less critical applications.
• General Utility: Any application where a stronger, more wear-resistant chain than Grade 30 is needed, but overhead lifting is not involved.

Important Limitations:

• No Overhead Lifting: Absolutely crucial – never use Grade 43 chain for lifting where a dropped load could cause harm.
• Working Load Limit (WLL): Never exceed the marked working load limit.
• Shock Loads: Avoid sudden impacts or jerking forces that can exceed the WLL.
• Compatibility: Ensure all connecting hardware (hooks, shackles, etc.) have a working load limit equal to or greater than the chain.
• Environmental Conditions: Extreme temperatures or corrosive environments can affect the chain’s strength. Consult the manufacturer for guidance in such conditions.

Sizes and Specifications:

Grade 43 chain comes in various sizes, with specifications that vary accordingly:

• Nominal Size (Diameter): Typically ranges from 1/4 inch to 1 inch or even larger.
• Working Load Limit (WLL): Increases significantly with the chain size, ranging from a few thousand pounds to over 20,000 pounds for the largest sizes.
• Proof Test Load: Generally twice the working load limit.
• Minimum Breaking Load: Typically three times the working load limit (based on a 3:1 design factor).
• Inside Length and Width: Vary depending on the chain size and link type (standard or short link).
• Weight per Foot: Increases with the chain diameter.

How It’s Sold:

• By the Foot or Meter: Cut to the specific length needed.
• By the reel:By the specific requirement from the customers.
• In Drums or Pails: For larger quantities.
• As Assemblies: With attached end fittings like hooks or shackles, often used as binder chains.

When selecting Grade 43 chain, always consider the specific application requirements, the necessary strength (WLL), the environment it will be used in, and ensure it is never used for overhead lifting. Always refer to the manufacturer’s specifications and guidelines for safe and proper use.