In modern engineering such as bridge construction, high-speed railways, and large-span venues, the stress relaxation performance of materials such as prestressed steel strands, steel wires, and threaded steel bars is a key indicator for measuring their long-term service capacity. Excessive relaxation rate can lead to loss of prestress, directly affecting the safety and durability of engineering structures. As a professional manufacturer in the field of material mechanics performance testing in China, Jinan Xinguang Testing Machine Manufacturing Co., Ltd. (hereinafter referred to as "Xinguang") has officially launched an upgraded series of microcomputer controlled relaxation testing machines with profound technical accumulation, providing high-precision and fully automatic testing solutions for the production inspection, quality certification, and engineering acceptance of prestressed materials.
The core of stress relaxation testing lies in accurately measuring the characteristics of stress decay over time of materials under constant strain state. The Xin Guang relaxation testing machine is designed strictly in accordance with national and industry standards, and has the following outstanding advantages:
1. Large tonnage bearing capacity, suitable for multiple specifications: In response to the testing needs of different specifications of prestressed materials, Xinguang can provide various tonnage models such as 300kN, 500kN, 600kN, etc., to meet the relaxation performance testing of steel strands, steel wires, and threaded steel bars with nominal diameters ranging from Φ 9.50mm to Φ 22.00mm. The host adopts a horizontal four column structure with strong frame rigidity and high stability, ensuring the authenticity and reliability of test data during long-term loading.
2. High precision measurement and control system, no grading throughout the entire process: equipped with high-precision load sensors, the accuracy of the test force indication is better than ± 1%, the effective measurement range covers 2% to 100% FS (no grading throughout the entire process), and the load measurement resolution is as high as 1/± 500000F.S, ensuring accurate measurement throughout the entire process. The displacement measurement resolution is as high as 0.001mm, and the deformation measurement range is 0.2% -100% FS, which can accurately capture the small deformation of materials during long-term loading.
3. Fully automatic closed-loop control, intelligent loading: using servo motor and precision screw pair transmission, with a speed range of 0.001-25mm/min, it can achieve uniform speed automatic loading. The equipment can load the specimen to 70% or 80% of the breaking load within 5 minutes according to standard requirements, maintain it for 2 minutes, and automatically start recording the test data. After reaching the set time, the test will be automatically terminated. The control system supports multiple control methods such as constant rate test force, constant rate stress, and constant rate displacement, and PID parameters can be adjusted online.
4. Long term testing and data calculation: The equipment testing time can reach over 1000 hours, fully meeting the long-term load requirements specified in the standard. At the same time, the system has strong data processing capabilities and can calculate the relaxation rate for 1000 hours based on 72-100 hours of experimental data, greatly reducing the actual experimental time and improving detection efficiency.
5. Multiple safety protections and user-friendly software: The device is equipped with multiple safety measures such as overload protection, overcurrent protection, and limit protection. It will automatically shut down when the test force exceeds 2% -5%. The measurement and control software independently developed by Xinguang supports automatic drawing of various test curves such as relaxation force time curve, force displacement curve, temperature time curve, etc. It automatically calculates the relaxation rate and generates detection reports that meet standard requirements.
The Xin Guang relaxation testing machine fully complies with the following national standards and industry specifications:
-GB/T10120-2013 "Test Method for Tensile Stress Relaxation of Metallic Materials"
-GB/T5224-2014 "Steel Strands for Prestressed Concrete"
-GB/T21839-2008 Test Methods for Steel Used in Prestressed Concrete
-GB/T5223.3-2005 "Steel bars for prestressed concrete"
The product is widely used in the following fields:
-Bridge engineering: Testing the stress relaxation performance of prestressed steel strands to ensure the long-term safety and reliability of the bridge prestressing system
-Rail Transit: Testing of Prestressed Materials for High Speed Railway, Urban Rail Transit and Other Projects
-Quality inspection agency: As the core equipment for third-party testing and certification, it carries out quality supervision and inspection of prestressed steel products
-Building materials: factory inspection and R&D analysis applied to steel strand, steel wire, and rebar production enterprises
Regarding Xinguang:
Jinan Xinguang Testing Machine Manufacturing Co., Ltd. was established in 2002. It is a high-tech enterprise specializing in the research and development, production, and sales of metal and non-metal material testing machines and detection instruments. The company is located in Zhangqiu District, Jinan City, Shandong Province. Its products cover a full range of categories including electronic universal testing machines, electro-hydraulic servo universal testing machines, relaxation testing machines, anchoring testing machines, fatigue testing machines, spring testing machines, etc. They are widely used in national defense and military industries, research institutes, quality inspection institutions, and major mining enterprises. The company has a 0.5 level production and manufacturing license, has passed ISO9001 quality system certification, and participated in drafting the JJF1296.1-2011 National Metrology Technical Specification for Static Uniaxial Test Machine Type Evaluation Outline.
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