GB/T 31979-2015Steel wire ropes -- Determination of rotational properties (English PDF)

Foreword

This Standard was drafted as per the rules specified in GB/T 1.1-2009.

This Standard adopted the re-drafting method to modify and use ISO 21669.2005 Steel

Wire Rope – Determination of Rotational Properties (English Version).

This Standard revised and supplemented the international standard in the following

aspects.

-- Add the reference of GB/T 16825.1 in the normative references;

-- Add the Appendix A Using Material Tester to Determine the Rotational Properties

of Steel Wire Rope.

For the benefit of convenient use, this Standard also made the following editorial

changes.

-- Delete the introduction of the international standard;

-- Change the standard name into Steel Wire Rope – Determination of Rotational

Properties;

-- Change "this international standard" into "this Standard";

-- Replace "comma" as a decimal point by a "decimal point".

This Standard was proposed by China Iron and Steel Industry Association.

This Standard shall be under the jurisdiction of National Technical Committee for

Standardization of Steel (SAC/TC 183).

Drafting organizations of this Standard. China National Center f or Quality Supervision

& Test of Metallic Products, China Metallurgical Information and Standardization

Research Institute, Guizhou Steel Rope (Group) Co., Ltd., Jiangsu Safety Wire Rope

Co., Ltd., Henan Zhongwei Metal Product Co., Ltd., Guangdong Kinlong Hardware

Products Co., Ltd.

Chief drafting staffs of this Standard. Hong Tao, Zhang Pingping, Wang Lingjun, Yang

Hongying, Yang Yuemin, Ren Cuiying, Zhu Hongbin, Hou Peizheng, Zhang Fang, Liu

Jianchun, and Li Min.

Steel Wire Ropes –

Determination of Rotational Properties

1 Scope

This Standard specifies the determination range of rotational properties of steel wire

rope, terms and definitions, specimen test device, test procedures, rotational

properties, test report etc.

This Standard is applicable to determine the rotational property of steel wire rope.

2 Normative References

The following documents are essential to the application of this document. For the

dated documents, only the versions with the dates indicated are applicable to this

document; for the undated documents, only the latest version (including all the

amendments) are applicable to this document.

GB/T 8706 Steel Wire Rope – Vocabulary, Designation and Classification (GB/T

8706-2006, ISO 17893.2004, IDT)

GB/T 16825.1 Verification of Static Uniaxial Testing Machines – Part 1.

Tension/Compression Testing Machines – Verification and Calibration of the

Force-Measuring System (GB/T 16825.1-2008, ISO 700-1.2004, IDT)

3 Terms and Definitions

The terms and definitions stipulated in GB/T 8706 are applicable to this document.

4 Specimen

The specimen shall be sufficient to represent the properties of the entire steel wire

rope, free from defects, and the steel wire rope shall be used independently for the

lifting load.

The free length between the specimen ends of steel wire rope shall be at least 100d,

d is the nominal diameter of steel wire rope in millimeter.

6 Test Procedures

Measure the free length of the steel wire rope specimen.

Exert the load to the tested steel wire rope specimen, and determine the benchmark

of pointer.

Lift the load from the ground, and ensure that the load and the ground to maintain a

certain distance.

Avoid the rotational inertia of the load from the rise to the balance position.

During the load exerting period, observe the full rotation number of the pointer, and

measure the angle that the pointer is deflected relatively from the benchmark.

Record the total angle that the point is deflected.

7 Rotational Properties

The rotational properties shall be determined by the rotation angle and specimen

actually-measured length, which are observed in the test.

The rotation angle observed in the test shall be converted into a value of steel wire

rope length of1000d.

When the measured free length of specimen is not 1000d, the rotation angle (the

number of rotation) observed at the free length between specimen ends shall be

converted to the rotation angle at the length of 1000d in the directly proportional

relationship. For instance, if the rotation angle observed at the free length of 250d is

1-turn rotation, the rotation angle per 1000d length is 4-turn rotation.

The rotational properties shall be expressed by the number of rotations per unit length

of 1000d, thereof 1-turn rotation is 360°.

8 Test Report

The test report shall include minimum the following contents.

a) Specimen number;

b) This Standard number;

c) Steel wire rope mark and minimum breaking force, in kN;

Appendix B

(Informative)

Application Guide of Rotation Joint

To limit the damage caused by the rotating load during the lifting operation, and

guarantee the personal safety of the staff on the operation site, it's better to select the

rotation-resisting steel wire rope with small rotation angle during the loading period,

see the situation in a). When using such steel wire rope, the application of rotation joint

can reduce the rotation due to the deflection of the steel wire rope on the pulley or

drum.

Other rotation-resisting steel wire rope with small rotation-resisting function during the

loading period can refer to the situation in b), the rotation joint can be used to minimize

the damage. However, in this case, it shall be recognized that excessive rotation may

adversely affect the properties of the steel wire rope, meanwhile it may also reduce the

breaking force of steel wire rope; the affecting degree may be determined by the

selected steel wire properties and the lifting load.

Each lifting operation shall be evaluated by the person in charge, meanwhile check s

the application requirement of rotation joint under the maximum lifting load according

to the crane manual, and inspect the steel wire rope within the specified cycle.

According to the rotational properties of steel wire rope, the application guide of

rotation joint is given as follows.

a) When the lifting load is equivalent to 20% Fmin, rotation angle is less than or equal

to 1-turn/1000d -- it can adopt the rotation joint;

b) When the lifting load is equivalent to 20% Fmin, rotation angle is greater than 1-

turn/1000d but less than or equal to 4-turn/1000d -- the rotation joint can be

adopted only when obtaining the recommendation from the steel wire rope

manufacturer or approval from the person in charge;

c) When the lifting load is equivalent to 20% Fmin, rotation angle is greater than 4-

turn/1000d -- it's not suitable for adopting rotation joint.

Thereof.

1-turn = 360°;

d = nominal diameter of steel wire rope;

Fmin = minimum breaking force of steel wire rope.

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