GB/T 38814-2020Steel wire ropes slings - Fatigue testing method (English PDF)

5.1 The cycle force accuracy of the fatigue testing machine shall not be lower

than level 2; it shall be calibrated or verified in accordance with GB/T 25917.1 or JJG 556.

5.2 Tensile test can use hydraulic universal testing machine which meets the

requirements of GB/T 3159, electronic universal testing machine which meets the requirements of GB/T 16491 or electro-hydraulic servo universal testing machine which meets the requirements of GB/T 16826.

Table 4 -- Breaking tension requirements of steel wire rope slings after

fatigue test Sling type Required value of breaking tension of sling Ferrule-securing sling Reach 80% of the minimum breaking force of the steel wire rope Socketing sling Reach 90% of the minimum breaking force of the steel wire rope Grip-secured sling Reach 70% of the minimum breaking force of the steel wire rope Splicing sling Reach 70% of the minimum breaking force of the steel wire rope Wedge socket-secured sling Reach 70% of the minimum breaking force of the steel wire rope

7.5.3 After the follow-up tensile test is over, visually inspect the specimen. There is no deformation or crack at the end of the sling; the main wire rope has no defects such as broken wires, broken strands, or broken ropes. If necessary, non-destructive testing can be carried out on the specimens after the subsequent tensile test is completed through negotiation between the two parties.

8 Results judgment The specimen shall meet the following two conditions at the same time, then the test result is valid:

a) The specimen is tested according to the stress amplitude required by the fatigue test, reaches the required number of cycles, meanwhile is qualified by visual inspection;

b) Carry out the follow-up tensile test, reach the required stress value, then the specimen passes the visual inspection again.

9 Safety measures During the entire test process, the test operator, observers and the entire environment shall take safety measures to ensure the safety of test personnel, observers and the environment. During the test, the steel wire rope may impact or penetrate distant objects, so during the test, adequate protection shall be provided for the specimens, operators and observers.

10 Test report The test report shall contain the following content:

a) Number of this standard;

b) Marking of steel wire rope specimens (such as structure, twisting method, nominal tensile strength, etc.);