Campbell-Mack Supply (1985) Ltd - Calgary

Wire Rope Classifications

Wire ropes are classified by the number of strands as well as by the number of wires in each strand. For example: 6 x 7, 6 x 19, 6 x 37, etc., where the first number is the number of strands, and the second number is the number of wires in each strand. Note, however, that these are nominal classifications and may or may not reflect the actual construction of a given rope.

The 6 x 19 classification includes six strands with each strand consisting of 15 to 26 individual wires. The six strands of a 6 x 37 class wire rope are constructed of 27 to 49 individual wires. Other popular classifications include 19 x 7, 7 x 19, and 8 x 19.

Every wire rope has three basic components: the wires, strands, and core. The core may be either fiber (FC) such as sisal, manila or jute, or an Independent Wire Rope Core (IWRC), which is actually a smaller wire rope within the strands of the outer wire rope.

The wires themselves are predominantly high-carbon steel but may also be various other alloys or metals such as iron, stainless steel, Monel, or bronze. Carbon steel wire rope is manufactured in various grades, including Improved Plow Steel (IPS), Extra Improved Plow Steel (EIPS) and Extra Extra Improved Plow Steel (EEIPS), which designate the nominal strength of the wire rope. EIPS is the most commonly used and manufactured grade today.

While 6 x 19 ropes give primary emphasis to abrasion resistance in varying degrees, 6 x 37 ropes are important for their fatigue resistance. This fatigue resistance is made possible by the greater number of small wires per strand.