ISO 15630-3 Steel Strands Relaxation Testing machine/Stress Relaxation Tester is a specialized instrument used to evaluate the stress relaxation behavior of metallic materials under constant strain at a fixed temperature over a defined period of time. This testing is essential for assessing material performance in long-term load-bearing applications, such as in prestressed steel reinforcement, wire, strand,and bars. 

ISO 15630-3 Steel for the reinforcement and prestressing of concrete — Test methods — Part 3: Prestressing steel

This standard specifies test methods applicable to prestressing steel (bar, wire or strand) for concrete.

Test principle: 

The relaxation test of steel strands is a test to measure the degree of deformation of steel strands after long-term stable loading. In this experiment, the steel strand first needs to be subjected to a constant load to ensure that it reaches a "steady state". After being subjected to a certain amount of load for a certain period of time, measuring the elongation generated by the steel strand can determine its performance under that load. This experiment can simulate actual usage conditions, thereby more accurately evaluating the service life and safety performance of steel strands.

Test steps: 

1. Pre treat the steel strand to achieve a stable state.

2. Apply a constant load to achieve a stable state.

3. Maintain a specified time under a constant load.

4. After stopping the load, record the length change of the steel strand.

5. Calculate the stress relaxation rate of steel strands based on experimental data.

Beijing United Test Co.,Ltd. export@unitedtest.com offer the ISO 15630-3 Steel Strands Relaxation Testing machine for the reinforcement and prestressing steel. Contact us now : export@unitedtest.com, unitedtest@hotmail.com