Prestressed steel strands, steel wires, and deformed steel bars serve as the "muscles" of modern major projects such as bridges, high-speed railways, and large-span venues. The stress relaxation property, which refers to the characteristic of a material where stress decays over time under a constant strain state, is a core indicator for assessing its long-term serviceability. An excessively high relaxation rate will directly lead to prestress loss, posing a threat to the safety and durability of engineering structures.
Characteristics of Xinguang relaxation testing machine:
1. Horizontal four-column structure, excellent long-term stability
The relaxation test requires continuous loading for over 1000 hours, posing stringent requirements on the rigidity and stability of the main equipment. The Jinan Xinguang relaxation testing machine adopts a horizontal four-column frame structure with strong rigidity. During the continuous loading process lasting for tens of days, the deformation is minimal, ensuring the authenticity and reliability of the test data.
2. High-precision measurement and control system, with no segmentation throughout the entire process
Equipped with a high-precision load sensor, the test force indication accuracy is better than ±0.5%, and the effective measurement range covers 2% to 100% FS (without any divisions throughout the entire range). Whether it's thin steel wire or thick steel strand, it can be accurately tested.
3. Displacement measurement at the micrometer level, capturing minute deformations
During the 1000-hour long-term loading process, the material undergoes extremely minor deformation, which is crucial for calculating the relaxation rate. The Xinguang relaxation testing machine boasts a displacement measurement resolution of up to 0.001mm and a deformation measurement range spanning from 0.2% to 100% FS, enabling precise capture of every micrometer-level deformation.
4. Fully automatic closed-loop control, intelligent loading
Utilizing a servo motor and precision screw pair transmission, uniform automatic loading can be achieved. The equipment can load the sample to 70% or 80% of the breaking load within 5 minutes according to standard requirements, maintain this for 2 minutes, and then automatically start recording test data. After reaching the set time, the test will automatically terminate, without any manual intervention throughout the process.
5. Data extrapolation function, doubling efficiency
Although the equipment can operate stably for over 1000 hours to complete a full cycle test, for daily batch testing needs, the system possesses powerful data extrapolation capabilities: it can extrapolate the relaxation rate for 1000 hours using test data from 72-100 hours, significantly reducing the actual testing time and improving testing efficiency.
6. Intelligent software, one-click report generation
The measurement and control software independently developed by Xinguang supports the automatic plotting of various test curves, including relaxation force-time curves, force-displacement curves, and temperature-time curves. It automatically calculates the relaxation rate and generates inspection reports that meet standard requirements.
Application scenario: Stress relaxation test of prestressed materials
Test objects: steel strands for prestressed concrete, prestressed steel wires, deformed steel bars, and PC steel bars.
Inspection standard:
GB/T10120-2013 "Metallic Materials - Tensile Stress Relaxation Testing Method"
GB/T5224-2014 "Steel Strands for Prestressed Concrete"
GB/T21839-2008 "Test Methods for Steel Products Used in Prestressed Concrete"
GB/T5223.3-2005 "Steel Bars for Prestressed Concrete"
Applicable fields
Bridge engineering: ensuring long-term safety and reliability of the prestressed system
High-speed railway: acceptance of track slabs and prestressed beam materials
Quality inspection agency: supervision and inspection of prestressed steel products, entrusted testing
Steel strand manufacturing enterprises: factory inspection, type inspection, research and development analysis
Scientific research institutes: new material research and development, standard setting
Product highlights:
Large tonnage: multiple specifications including 300kN/500kN/600kN, compatible with the full range of prestressed materials
Long-term stability: Horizontal four-column structure, capable of continuous operation for over 1000 hours
High precision: test force indication error ≤±0.5%, displacement resolution 0.001mm
Fully automatic: one-click start, automatic loading, maintaining, recording, and terminating
High efficiency: 72 hours of data can be used to predict the relaxation rate for 1000 hours
Intelligentization: Automatically drawing curves, calculating relaxation rates, and generating inspection reports
CH
EN
