GB/T 8358-2023Steel wire ropes - Determination of breaking force (English PDF)

1 Scope

GB/T 8358-2023 specifies the determination of the breaking force of steel wire ropes. Every crane, lift, mine hoist and mooring in the country is designed against a stated minimum breaking force, and that figure comes from pulling a sample of the rope apart. The difficulty of the test is in the ends rather than the middle: if the specimen is gripped badly it fails at the termination and the result is meaningless, so the sample is normally socketed with a poured resin or metal grouting. The standard sets the principle, the specimen preparation, the test equipment, the test procedure and the test report, with an informative annex on the method of pouring the grouting material. It took effect on 1 December 2023.

This document specifies the principles, specimen preparation, test equipment, test procedures, and test reports for the method to determine the breaking tensile force of steel wire ropes. This document is applicable to the determination of breaking force of various wire rope products.

2 Normative references

The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.

GB/T 8706, Steel wire ropes -- Vocabulary, designation and classification ( GB/T 8706-2017, ISO 17893:2004, MOD)

GB/T 16825.1, Metallic materials -- Calibration and verification of static uniaxial testing machines -- Part 1: Tension/compression testing machines -- Calibration and verification of the force-measuring system ( GB/T 16825.1-2008, ISO 7500-1:2004, IDT)

GB/T 30588, Terminations for steel wire ropes -- Molten metal socketing YB/T 4615, Steel rope end resin socket JJG 139, Verification regulation of Tension, Compression and Universal Testing Machines JJG 475, Verification Regulation of Electronic Universal Testing Machine JJG 1063, Verification Regulation of Electro-hydraulic Servo Universal Testing Machines

3 Terms and definitions

For the purposes of this document, the terms and definitions defined in GB/T 8706 as well as the followings apply. A specimen installation method is to clamp the specimen directly into the appropriate jaws of the tensile testing machine for tensile testing.

3.9 method of wrapping A specimen installation method that is to directly wrap the specimen in the rope groove of the winding test wheel for tensile testing.

4 Principle

Apply tensile force to the wire rope specimen. Stretch until the wire rope breaks. Determine the breaking tension of the wire rope, or stretch it to the specified tension value.

6 Test equipment

6.1 This test can be performed on any tensile testing machine that meets the requirements of this document.

6.2 The force measuring system of the testing machine shall comply with the requirements of GB/T 16825.1. Calibrate in accordance with JJG 139, JJG 475 or JJG 1063. Its accuracy shall be grade 1 or better.

6.3 The testing machine shall be equipped with safety protection devices to prevent wires from flying out and injuring people during the test.

7 Test procedures

7.1 Unless otherwise specified, the test is generally conducted at room temperature within the range of 10°C~35°C. For tests with strict temperature requirements, the test temperature shall be 23°C±5°C.

7.2 Mount the specimen on the tensile testing machine. Ensure that the axis of the specimen coincides with the axis of the chuck of the testing machine.

7.3 For tensile specimens produced by method of alloy poured socketing or method of resin pouring, when testing with a vertical tensile testing machine, first place the specimen in the upper and lower jaw seats. Let the specimen in the lower jaw seat hang