The core is the central part of a steel wire rope, categorized into ​metal cores and ​fiber cores. Its primary functions include providing structural support, reducing inter-strand pressure, and (for fiber cores) offering lubrication, corrosion resistance, and oil retention. The types of steel wire rope cores are as follows:

​1. Metal Core

• ​A. Independent Wire Rope Core (IWR): A core made of an independent wire rope.
• ​B. Independent Wire Strand Core (IWS): A core composed of a single wire strand.

​2. Fiber Core

• ​A. Natural Fiber Core: Made from materials such as sisal, cotton, jute, or other compliant natural fibers.
• ​B. Synthetic Fiber Core: Constructed from polyethylene, polypropylene, asbestos, or similar synthetic materials.

​Representation in Cross-Sectional Diagrams

The core type is visually distinguished in cross-sectional diagrams. For example:

• ​Figure 1-1 (6×7): Labeled as ​6×7+FC (Fiber Core), where the core is typically shaded gray or black.
• ​Figure 1-2 (7×7): Labeled as ​7×7+IWS (Independent Wire Strand Core), with the core depicted as a distinct structural element.

Figure 1-1 ：6×7               Figure 1-2 ：7×7

​Key Differences and Characteristics

​Fiber Core (FC)

• ​Material Example: Sisal-based fiber cores.
• ​Advantages:
  • Stores lubricating oil, ensuring sustained lubrication of the steel wire rope.
  • New fiber cores contain ​12–15% oil, which gradually depletes during use (e.g., worn cores may retain only ​2.4% oil).
  • Regular lubrication reduces wire fractures by approximately ​50% in later service stages.
  • Initial oil content supports only ​40% of the rope’s lifespan; without replenishment, fractures increase sharply.
• ​Applications: Suitable for dynamic environments. For harsh or static conditions, corrosion-resistant coatings (e.g., galvanized or aluminum-coated ropes) are recommended.

​Metal Core (IWS/IWR)

• ​Advantages:
  • Higher wear resistance, crush strength, and breaking load compared to fiber cores.
  • Longer service life, particularly under heavy loads or abrasive conditions.
  • Slightly reduced flexibility due to the rigid core.
• ​Applications: Ideal for cranes, hoists, or winches where durability and load capacity are critical.
• ​Cost Considerations: Metal-core ropes are more expensive initially but offer better cost efficiency over time due to extended lifespan and performance.

​Summary

• ​Fiber cores prioritize flexibility, lubrication, and corrosion resistance, ideal for dynamic or corrosive environments.
• ​Metal cores excel in strength, durability, and load-bearing capacity, suited for heavy-duty machinery.
• Selection depends on operational demands, balancing cost, lifespan, and environmental factors.