Fence Net Testing

Fence mesh inspection mainly conducts scientific testing and analysis on the material composition and mechanical property testing, mesh size and wire diameter measurement, surface treatment layer testing, overall structure and dimension testing, environmental aging resistance testing, and safety and protection performance evaluation, objectively assessing the product quality grade and issuing a detailed test report, providing a basis for manufacturers' quality control and downstream users' product acceptance.

Testing Items

Material composition and mechanical property testing: Through the chemical analysis (such as the spectroscopic analysis), the chemical compositions of the metal wires used for the fence meshes (such as the low-carbon steel wires and stainless steel wires) are determined, ensuring that they meet the design standards. At the same time, the tensile testing, bending testing and torsion testing are carried out, determining the key mechanical indicators such as their tensile strengths, yield strengths and elongations, evaluating their load-bearing capabilities and deformation resistance.

Mesh size and wire diameter measurement: The high-precision callipers, projectors or image measuring instruments are used to precisely measure the mesh sizes (such as the side distances and aperture diameters) and metal wire diameters of the fence meshes. This item is the core of evaluating the product specification consistency and safety protection clearances, ensuring that they can effectively block the passage of the predetermined targets (such as the people, animals or small objects).

Surface treatment layer testing: Evaluating the anti-corrosion layers such as the galvanizing, plastic coating (PVC/PE) and powder spraying. The testing contents include the coating thicknesses (using the magnetic or eddy current thickness gauges), adhesion (cross-cut method or tensile method), uniformity and corrosion resistance (such as the salt spray testing), to verify their durability for the long-term outdoor use.

Overall structure and dimension testing: Checking the overall widths, heights, diagonal differences of the mesh sheets, frame dimensions and other macro geometric parameters of the fence meshes. At the same time, their structural stability is evaluated, such as the firmness of the mesh welding points or weaving points and the connection strengths between the frames and posts, ensuring the overall stiffness and stability after the installation.

Environmental aging resistance testing: Through the artificial accelerated aging testing (such as the UV aging and xenon lamp aging), the long-term outdoor environments such as the sunlight irradiation and rain are simulated, evaluating the aging resistance, powdering resistance and color change resistance of the fence mesh materials and their surface coatings, predicting their service lives and appearance retention capabilities.

Safety and protection performance evaluation: According to the specific application scenarios (such as the sports fields, prisons and highways), the impact testing (falling ball testing), anti-climbing testing, blade barbed tape sharpness and shear strength testing are carried out, quantifying their actual safety protection effectiveness.

Testing Scope

Woven mesh fences: Including the common chain link fences (protective meshes), diamond meshes and rolled wire meshes, widely applied to the sports fields, slope protection and farms. The testing emphases are the firmness of the mesh nodes, mesh uniformity and material flexibility, ensuring that they can not only effectively intercept but also have certain buffering effects.

Welded mesh fences: Such as the square hole welded wire meshes and frame isolation fences, often used for the separation of the factory areas, parks and highways. The testing core is the shear and tensile strengths of the weld points, as well as the overall flatness and dimension precision of the meshes, preventing the structural failures caused by the weld point opening.

Barbed tape and barbed wire fences: Including the razor wire and spiral barbed tape, mainly used for the perimeter protection of the high safety grade areas. The testing needs to emphatically focus on the material hardness, sharpness and coating corrosion resistance of the blades, as well as the tensile strengths of the core wires, ensuring that they have the effective deterrence and blocking functions.

Posts and connecting parts: The supporting structures of the fence systems, such as the steel pipe posts, concrete posts and the related connecting clamps and bolts. The testing items cover the materials, wall thicknesses, verticality and anti-corrosion layer qualities of the posts, as well as the dimension matching and anti-disassembly properties of the connecting parts.

Products with the different surface treatments: The testing scope covers the hot-dip galvanized fence meshes, electro-galvanized fence meshes, dip-coated fence meshes and powder-sprayed fence meshes. The testing parameters need to be set according to the different process characteristics, such as measuring the zinc layer thicknesses and uniformity for the galvanized layers, and measuring the plastic layer thicknesses and adhesion for the coated layers.

Customized special-shaped fences: The non-standard fence products designed for the special terrains or uses. The testing needs to be based on the technical drawings or agreements confirmed by the supply and demand parties, comprehensively verifying all the customized dimensions, structures and function requirements, ensuring the conformity with the specific use scenarios.

Testing Methods

Dimension measurement method: The measuring tools such as the vernier callipers, micrometers and steel tapes are used for the direct measurement. For the batch parameters such as the meshes, the sampling statistical methods can be adopted. The image measuring instruments are suitable for the complex profiles and batch fast testing, which can precisely obtain the two-dimensional dimension data, ensuring the objective and accurate results.

Mechanical property testing method: The tensile testing is carried out on the universal material testing machines, obtaining the stress-strain curves and calculating the tensile strengths and yield strengths. For the bending testing, the specimens are bent around the bending mandrels of the specified diameters to the specified angles, checking whether the cracks occur on the surfaces, evaluating their plastic deformation capabilities.

Coating property testing method: The coating thicknesses are measured with the magnetic method (steel substrates) or eddy current method (non-ferrous metal substrates). For the adhesion, the cross-cut method is commonly used. The grids are cut with the cutting tools, the adhesive tapes are attached and then pulled, observing the coating peeling conditions. The salt spray testing is carried out in the salt spray chambers, simulating the marine atmospheric environments and evaluating the corrosion resistance.

Chemical analysis method: The spectroscopic analysis (such as the direct-reading spectrometers) or wet chemical analysis is adopted to carry out the quantitative analysis of the contents of the elements such as the carbon, manganese, silicon, sulfur and phosphorus of the fence mesh metal materials, ensuring that the raw material compositions meet the requirements of the corresponding designation standards (such as Q195 and Q235).

Non-destructive testing method: For the welding nodes, the dye penetrant testing or ultrasonic testing can be adopted to detect whether there are the internal defects such as the micro cracks, false welds and missed welds. This method does not destroy the products, and is suitable for the quality monitoring during the production processes and the finished product sampling inspection.

Artificial weathering aging testing method: The specimens are placed in the UV aging test chambers or xenon lamp aging test chambers, setting the specific illumination, temperature, humidity and spraying cycles, simulating and accelerating the natural aging processes. The changes such as the colors, gloss, powdering and cracking are regularly observed and recorded.

Testing Standards

Domestic Standards:

1. GB/T 700, Carbon structural steels

2. GB/T 228.1-2021, Metallic materials — Tensile testing — Part 1: Method of test at room temperature

3. GB/T 232-2010, Metallic materials — Bend test method

4. GB/T 10125-2021, Corrosion tests in artificial atmospheres — Salt spray tests

International Standards:

1. ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature

2. ISO 9227, Corrosion tests in artificial atmospheres — Salt spray tests

Note: The applicable standard can be selected according to the product use and customer trade requirements; standards agreed in the contract take precedence over general standards.

Testing Instruments and Equipment

Universal material testing machine: The core equipment used for the mechanical property testing such as the tensile, compression, bending and shear of the fence mesh wires, weld points and overall components. Through the high-precision transducers and control systems, the load and displacement data can be precisely recorded, and the test reports are automatically generated. It is the key tool of evaluating the product structural strengths.

Coating thickness gauge: Divided into the magnetic thickness gauges and eddy current thickness gauges, respectively used to measure the non-conductive coating thicknesses (such as the paints, plastics and zinc layers) on the steel substrates and non-ferrous metal substrates. The equipment is portable and quick to operate, and can carry out the multi-point measurements on the products at the production sites or in the laboratories, ensuring that the coating thicknesses are uniform and up to the standards.

Salt spray corrosion test chamber: By atomizing the sodium chloride solutions, the constant high-temperature, high-humidity and high-salt-spray-concentration corrosive environments are created in the chambers, used to accelerate the evaluation of the corrosion resistance of the fence mesh metal substrates and surface treatment layers. The testing periods can be set according to the standards (such as GB/T 10125), usually measured in hours, simulating the outdoor corrosion effects of several years.

Spectroscopic analyser: Mainly using the direct-reading spectrometers (OES), which can carry out the fast composition analysis of the metal samples within seconds, precisely determining the contents of the multiple elements such as the carbon, silicon, manganese, phosphorus and sulfur. This equipment is the important link of the raw material incoming inspection and quality control, ensuring that the material chemical compositions meet the standard provisions.

Image measuring instrument (two-dimensional): Using the high-resolution CCD cameras and precision optical systems, combined with the professional measurement software, the non-contact precision measurement of the two-dimensional geometric parameters such as the mesh sizes, wire diameters and diagonal lengths of the fence meshes can be carried out. With the batch automatic measurement functions, the efficiency is high and the repeatability is good.

Artificial weathering aging test chamber: Including the UV aging chambers and xenon lamp aging chambers. The UV aging chambers use the fluorescent UV lamps to simulate the ultraviolet band in the sunlight, mainly testing the photo-aging; the spectra of the xenon lamp aging chambers are closer to the full solar spectra, which can simultaneously test the aging effects of the factors such as the light, heat and humidity, used to evaluate the coating weatherability.

Precision dimension measuring tool set: Including the digital vernier callipers, outer diameter micrometers, steel tapes, feeler gauges and thread gauges. These basic but indispensable tools are used for the fast on-site inspection of the macro dimensions, clearances and thread specifications of the fence meshes and posts, and are the common equipment for the preliminary quality judgment.