Steel, of which cut steel fibers are widely used and have high tensile strength. Using low carbon alloy as the base material, the cut steel fiber produced by cold drawing technology at the temperature of metal crystal has a tensile strength of 1150-3000MP. It is widely used in the reinforcement of industrial floors (logistics, cold storage, outdoor, storage) and the improvement of cracking conditions.
The aspect ratio is made by cutting thin wire method, cold-rolled strip shearing, steel ingot milling or molten steel rapid condensation method (the ratio of fiber length to diameter, when the fiber cross-section is non-circular, the diameter of the equivalent cross-sectional circle area is converted) 30 to 100 fibers. Due to the different preparation methods, the properties of steel fibers are very different, such as the tensile strength of cold-drawn steel wire is 380-3000MPa, the tensile strength of cold-rolled strip shearing method is 600-900MPa, and the ingot milling method is 700MPa; molten steel condensation Although the method is 380MPa, it is suitable for the production of heat-resistant fibers.
Thin steel wires of a range of lengths and diameters added to reinforce mortar or concrete. Commonly used long straight steel fibers with circular cross-sections have a length of 10-60 mm, a diameter of 0.2-0.6 mm, and an aspect ratio of 30-100. In order to increase the interface bonding between fibers and mortar or concrete, various special-shaped steel fibers can be selected, and their cross-sections are rectangular, zigzag, and meniscus; the cross-sectional size changes alternately along the length; corrugated; circular; Enlarged ends or hooked, etc. When using a non-circular section
When the steel fiber is in shape, its equivalent diameter (de) can be calculated as follows: 
where a is the actual cross-sectional area of the steel fiber.
In order to disperse steel fibers in mortar or concrete more uniformly and increase the aspect ratio of fibers, steel fibers bound together by water-soluble glue into bundles can be used. Steel fibers can be manufactured by cold-drawn wire cutting, sheet steel shearing, steel block or ingot milling, and molten steel drawing. Low carbon steel fibers can be used to prepare steel fiber reinforced concrete applied at room temperature; stainless steel fibers must be used to prepare refractory steel fiber reinforced concrete. Adding an appropriate amount of steel fiber to mortar or concrete can improve its tensile and flexural strength, and greatly improve its toughness and impact strength.
