In industrial quality control and material research, tensile pressure testing machine is the core equipment to evaluate the mechanical properties of materials such as tensile and compressive resistance. It provides accurate data for material selection, product design, and quality acceptance by simulating actual stress scenarios, and its type selection and specification maintenance directly affect the reliability of test results.
Core types and applications
Material testing machines need to be classified according to testing requirements, and the core is divided into three categories, with clear functions and applicable scenarios.
Tensile testing machine
It is mainly used to measure the mechanical properties of metal wires (such as steel wires), bars (such as steel bars) and non-metallic materials (such as plastic films and rubber strips), and can detect key parameters such as tensile strength, yield strength, and elongation. The equipment is equipped with a special chuck (wedge chuck for metal, pneumatic chuck for non-metal) to ensure that the specimen does not slip when stretched, and the loading method is mainly electric or hydraulic drive, which can achieve smooth and uniform loading.
Pressure testing machine
Compression and bending tests of heavy metal/non-metallic block materials (such as concrete test blocks, ceramics) and structural parts (such as automobile chassis brackets), and core tests of compressive strength and flexural strength. It has a large tonnage span, covering from small parts testing of several tons to testing concrete components of hundreds of tons, and some models can quickly switch test types by changing tooling (e.g. bending bearings).
Universal testing machine
Integrating various functions such as stretching, compression, bending, and shearing, multiple types of tests can be completed by simply changing the chuck or tooling without changing equipment. Modern universal testing machines are mostly electronic control systems, which support computer collection of force-displacement curves and generate reports, with high accuracy (value error ≤±1%), which is suitable for batch testing in multi-category quality inspection centers for material research and development of scientific research institutions.
Maintenance and maintenance points
The accuracy of the equipment is maintained and the service life is extended, relying on standardized installation, use, verification and daily maintenance.
Basic requirements: installation and use specifications
Installation: Choose a stable, clean and dry, vibration-free site (away from machine tools and fans), and control the ambient temperature at 10-35°C; The upper and lower chucks must be concentric (deviation ≤ 0.1mm) to avoid the force of the specimen eccentricity; The hydraulic equipment should ensure that there is no leakage of the oil pipe and that the electrical part is insulated reliably (grounding resistance ≤ 4Ω).
Use: The loading and unloading load should be stable and shock-free, and the pointer or electronic display should not stagnate or jump during continuous loading; The test load should be between 10% and 100% of the equipment range (less than 10% will increase the error); When the load exceeds the range by 3%-5%, the overload safety device should be automatically stopped to prevent damage to the equipment.
Value Verification: Ensure accuracy compliance
The verification period is 1 year, and it needs to be carried out in accordance with the "Tensile, Pressure and Universal Testing Machine Verification Regulations" (JJG (Machinery) 026-2020), including appearance (complete equipment identification, no rust), performance (stable loading, effective protective device) and value accuracy.
Commonly used verification tools are special weights with a tolerance of ±0.1%, a calibration lever ± 0.2%, or a third-class standard force gauge with a force measurement range of 10N-10MN (measurement traceability is required); Each level of the dial should select no less than 5 test points, load each point 3 times to take the average, and test the difference between the indicated value in the loading and unloading process at the same time.
Error handling and troubleshooting
Error source: Common errors are mostly due to improper installation (the chuck is not concentric and causes positive difference, and the force measuring mechanism is not level and the force measuring mechanism is not level leading to negative difference) or friction (oil cylinder dirt, oil viscosity is abnormal), priority is eliminated by correcting the installation, cleaning the cylinder, replacing the hydraulic oil, and it is not easy to cover up the problem by increasing or decreasing weights or software forced correction.
Troubleshooting: If there is no response to loading, you can check the power supply or oil circuit; If the display value is unstable, you need to check the gear meshing or sensor connection; Hydraulic oil leakage needs to be tightened or the sealing ring should be replaced, and the fault should be dealt with in time to avoid the problem from expanding.
Routine maintenance: Extend the life of the equipment
After each test, use neutral detergent to clean the specimen residue and oil stains, and cover the dust cover when not in use for a long time; Fill the moving parts (chuck guide posts, pendulum bearings) with special lubricating oil every month and change the hydraulic oil every 6-12 months (No. 46 anti-wear hydraulic oil recommended).
Check the tightness of the tubing, the integrity of the electrical circuit and the wear of the collet every week; Strictly use the equipment within the range, and set up a special person to be responsible for operation and maintenance to ensure that the verification is completed once a year and maintain the compliance operation of the equipment.
summary
The Tensile Testing Machine is the "bridge" between material properties and practical applications, and its type selection needs to accurately match the test object (such as tensile machine for metal, universal machine for multi-scene use), and standardized maintenance (from installation and calibration to daily cleaning) is the key to ensuring reliable test data and long-term stable operation of equipment. Whether it is quality control in industrial production or material innovation in the field of scientific research, only by fully grasping the characteristics of equipment and implementing maintenance processes can the tensile pressure testing machine continue to play its value and provide strong data support for various scenarios.
