The quality inspection standards for welded mesh cover multiple aspects to ensure that the products meet the usage requirements. The following is a detailed review of the quality inspection standards for welded mesh sheets:

I. Appearance Inspection Standards

Surface quality

The surface of the mesh should be smooth and flat, free from defects such as cracks, folds, scars and pits.

The weld points should be firm, without any open welding or false welding.

Minor burrs or surface rust at the weld points are allowed, but they must not affect the use.

Color and logo

The surface of the galvanized mesh should present a uniform silver-white color, free from defects such as missed plating and zinc tumors.

The color of the plastic-coated mesh should be uniform and consistent, without any color difference, bubbling, peeling or other phenomena.

The mesh should be accompanied by a label indicating the specification, production date and quality inspection approval stamp.

Ii. Dimensional Measurement Standards

Geometric dimensions

The deviation of the length, width and grid size of the mesh should be controlled within ±10mm (some high standards require within ±5mm).

The difference between the two diagonals should not exceed 10mm to ensure the regular shape of the mesh.

The allowable deviation of the steel bar diameter is ±0.3mm, and the cumulative deviation of the grid spacing should be ≤10mm.

Flatness

The flatness of the mesh should be ≤2mm/m to ensure that the mesh is flat and free of warping during use.

Iii. Material Inspection Standards

Chemical composition

The chemical composition of steel should comply with national standards (such as GB/T 1499.2-2018 "Steel for Reinforced Concrete") to ensure the stability of material performance.

Physical properties

Tensile strength: Cold-rolled ribbed steel bars should be ≥500MPa to ensure that the mesh has sufficient load-bearing capacity.

Yield strength: It should reach the specified value to ensure that the mesh does not undergo plastic deformation under force.

Elongation after fracture: It reflects the plastic deformation capacity of the material and must comply with relevant standards.

Bending performance

After the sample is bent 180 degrees, there should be no transverse cracks to ensure that the mesh will not break when bent for use.

Iv. Process Inspection Standards

Welding quality

The solder joints should be full and free of defects such as cracks, pores and slag inclusions.

The open welding rate of weld points should be controlled at an extremely low level (for example, the open welding rate of intersection points ≤1%, and the number of open welding points of a single reinforcing bar ≤50%).

The shear strength of the weld point should be ≥ 80% of the tensile strength of the reinforcing bar to ensure that the welded joint is firm and reliable.

Coating treatment

The thickness of the galvanized coating should be ≥50μm (some high standards require ≥70μm) to ensure that the mesh has good corrosion resistance.

The plastic coating should be uniform without any phenomena such as bubbling or peeling, and the color should meet the customer's requirements.

V. Performance Testing Standards

Tensile strength test

Samples are cut from the mesh for tensile tests until they break. The test results should show that the tensile strength is ≥500MPa (for cold-rolled ribbed steel bars).

Solder joint shear force test

The shear strength of the weld points is tested by a special fixture to ensure that the weld points will not fall off easily under force.

Corrosion resistance test

Conduct a neutral salt spray test (such as 120 hours) on galvanized or plastic-coated mesh sheets to evaluate their anti-rust performance. After the test, there should be no severe rusting on the surface of the mesh.

Weather resistance test

Simulate different climatic conditions (such as high temperature, low temperature, humidity, etc.) to test the weather resistance of the mesh. Ensure that the mesh maintains stable performance in all kinds of environments.