EUROPEAN STANDARDS E.G., EN 12385 SERIES.

Many stranded steel wire ropes are manufactured to standards compliant with the EN 12385 series. They include those used for general lifting applications within part 4 of this standard, EN 12385-4 “Steel wire ropes - Safety - Part 4: Stranded ropes for general lifting applications”. In this standard there are breaking strength tables for the different rope constructions and nominal diameters. The Minimum Breaking Force (MBF) for each rope diameter within these tables are specified in relationship to a rope grade, typically 1770, 1960, 2160. However, rope manufacturers also produce rope constructions offering increased breaking strength and performance which are used extensively, but their breaking strengths are not specifically given within these tables. The rope breaking strengths for those rope constructions, often referred to as high performance ropes, may be specified in the individual rope manufacturers catalogue. In these standards, rope grade (Rr) and wire tensile grade (R) are described:

Rope grade (Rr): is a level of requirement of breaking force which is designated by a number (e.g. 1770, 1960, 2160) Extract: EN 12385-2 clause 3.10.11
Note: It does not imply that the actual tensile strength grades of the wires in the rope are necessarily of that grade.

Wire tensile grade (R): a level of requirement of tensile strength of a wire and its corresponding range. It is designated by the value according to the lower limit of tensile strength and is used when specifying wire and when determining the calculated minimum breaking force or calculated minimum aggregate breaking force, expressed in N/mm2. Extract: EN 12385-2 clause 3.1.10. 

For those ropes where a rope grade is applicable, the tensile strength grades of the wires shall be subject to the limits given in the below. Extract: EN 12385-4 clause 5.2.1

Wires: wires before ropemaking, shall conform to EN 10264-2.

Wire tensile strength grade - permitted variations: the tensile strength grades are specified in EN 10264 parts 2, 3 and 4. These values are the lower limits for tensile strength of each wire grade. The permitted upper limit for non-alloy steel wire for ropes for each grade shall not exceed the lower limits by a value greater than the values given in the table below. Extract: EN 10624-1 clause 5.2.1.

Compliance with the rope grade requirements shall be through a visual verification of the inspection documents supplied with the wire in relation to the minimum breaking force value of the rope. Extract: EN 12385-4 clause 6.5.

Example:
26 mm, Dyform 6xK36WS-IWRC, 1960 grade, galvanized(B), RHOL(sZ), MBF 560 kN rope grade 1960, which allows for wire tensile grades 1770 to 2160. Outer wire diameter 1.47 mm, which has a permitted tolerance of 320 N/mm2. Individual outer wires within this rope could have an actual tensile of between 1770 N/mm2 and 2450 N/mm2 

Therefore, this rope could be described and certified as a 1770, 1960 or 2160 grade provided the minimum breaking force value was achieved

AMERICAN SOCIETY FOR TESTING AND MATERIALS SPECIFICATION A1023.

The standard specification A1023 - Stranded Carbon Steel Wire Ropes for General Purposes is the most widely used rope standard in North America and is distributed by ASTM through governance of American National Standards Institute (ANSI). A1023 also specifies the rope grades in a similar way to the EN standard. For those ropes where a rope grade is applicable, the tensile strength grade of the wires shall be subjected to the limits in the table below. Extract: API 9A table 1

Requirements for wire tensile strength are determined by either the wire level, as specified in ASTM Specification A1007, or by the tensile strength grade, as specified in ISO 2232. Extract: A1023, Section 3.13.2

AMERICAN PETROLEUM INSTITUTE (API) SPECIFICATION 9A.

A standard in frequent use in the oil and gas industries, is the American Petroleum Institute (API) specification 9A “Specification for steel wire ropes”, adopted the rationale
for rope grade specification from A1023. For those ropes where a rope grade is applicable, the tensile strength grade of the wires shall be subjected to the limits in the table below. Extract: API 9A table 1.

Notes:

1. The method of test for wires of tensile strength grades 1770, 1960, 2160 shall be in accordance with those given in ISO 2232.
2. The method of test for wires of tensile strength grades Level 2, 3, 4 and 5 shall be in accordance with API 9A Annex B.
3. Not all ropes (e.g., large diameters, typically above 60 mm) will necessarily have a nominated rope grade

The permitted variations in tensile strengths of non-alloyed steel wires shall not exceed the nominal values by an amount greater than given in the table below. Extract: API 9A table A. 1for rope grade specification from A1023. For those ropes where a rope grade is applicable, the tensile strength grade of the wires shall be subjected to the limits in the table below. Extract: API 9A table 1.