Steel ropes

Three basic components are used for producing ropes

• steel, aluminum, copper wire rope
• core of rope
• rope lubricant

Wire rope

Steel is most often used for the production of mechanical stressed ropes. Ferrous metals are used only if the rope leads an electrical current. The basic part of the rope consists of wire which has properties that also affect the properties and quality of the resulting wire rope. Wire for steel wire ropes is made of unalloyed carbon steel grade 12.

The quality of wire is affected by:

• the size and amount of admixtures in the wire
• the size and amount of surface defects in the wire which occur by rolling or pulling
• the structure of the wire
• the temperature when processing the wire

Rope core

The task of the rope core is to create a firm but flexible base for the wire strands which are twisted spirally around the core. The core prevents radial shifting and side pressure of the strands and at the same time fills the space between the strands. Another task of the core is to ensure the circular cross section of the wire rope. The material of the core is most often made of various plastics. They are resistant against higher temperatures, have more abrasion resistance and, in comparison to natural materials used in the past, have better tensile strength. The core must have a porous structure in order to absorb sufficient amounts of lubrication. In some cases the rope core is made of metal, mainly in operations with temperatures higher than 60 °C and when a larger load is required from the rope for the given cross section. The lubrication part is then inserted between the inner rope and its sheath in the form of strands. These types of ropes are stiffer.

Rope lubricant

The lubricant protects the rope from corrosion, reduces friction between the wires and strands, reduces friction between the rope and block and prevents impurities and water from penetrating the inside of the rope.

Required properties:

• the lubricant must not leak out
• the lubricant must not be removable with water and liquids with which it comes into contact
• the lubricant must be permanent and resistant to the effects of wind and temperature, hereby also protecting the rope from corrosion
• the lubricant must not be corrosive or cause any other chemical reaction to the wire

Lubricants are manufactured according to the purpose of the rope, special lubricants are used for lubricating ropes in operation.

Rope structure:

Is determined mainly by the mutual arrangement of wires in the strand and the strands themselves. The basic structures are defined in STN 02 43xx

Marking of wire ropes:

Ropes are marked with the technical standard and additional numbers
Example of marking: 12 STN 02 4324.45
Number before STN – nominal diameter of the rope
The first digit after the standard number – nominal wire strength
The second digit after the standard number – surface treatment of wire, direction and method of winding

Digit	Nominal wire strength in MPaa
2	1270
3	1370
4	1570
5	1770
6	1960
7	1670
0	1770

Digit	Surface wire	Method of winding	Direction of winding
1	bare	counter direction	right
2	bare	counter direction	left
3	bare	same direction	right
4	bare	same direction	left
5	galvanized	counter direction	right
6	galvanized	counter direction	left
7	galvanized	same direction	right
8	galvanized	same direction	left

Základní konstrukce lana

• single-stranded ropes
• traditional ropes, standard
• parallel ropes, SEAL
• flexible cables, Hercules
• Warrington ropes
• ropes from wrought wire
• stainless steel ropes
• electrical cables
• other ...