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Steel Bar Process Performance
- Jul 05, 2017 -

Steel Bar Process performance

Reinforcement process performance includes many projects, different characteristics for different products can be made, such as ordinary steel requirements for bending and reverse bending (reverse bending) test, some prestressed steel is required to repeat bending, twisting, winding test.

The form of all these tests varies the extent to which the material may be involved in the actual use of the material, such as ordinary bars need to hook or bend molding, prestressed steel sometimes wrapped, etc., and its purpose is to assess the material for these specific plastic Deformation of the ultimate capacity, and thus the performance of the material is also the plastic requirements of the material, and with the ductility (elongation) requirements are connected, in general, elongation of steel, its process performance is also good.

However, compared with the uniaxial force state at the time of stretching, the stress state of the process performance test is much more complicated. The deformation type and size of the specimen are different (axial and radial). The steel structure, Particle size, detrimental residual element content, especially internal and surface Any defects that affect continuous deformation such as cracks, inclusions, etc. may affect and cause the test not to pass. So in a sense, for the assessment of the quality of steel, it can be said that the process performance test more stringent.

In addition, the reverse bending test of steel is essentially a strain aging sensitivity test. This is because the molten steel generally contains a certain amount of free nitrogen (N), also known as residual nitrogen, the content is too high, can lead to plastic deformation of steel After brittle at room temperature.

As the steel often need to be bent after the use of, has produced a plastic deformation, if the material becomes brittle, the structure can not bear the steel and then produce plastic deformation of the external load (such as earthquakes), so at home and abroad will be bent as a test Important technical requirements are included in the steel standard, while the nitrogen content of steel to be limited (not more than 0.012%).

Studies have shown that some elements of microalloying for steels such as vanadium, titanium, niobium and so on, especially vanadium and nitrogen have excellent affinity, the addition of vanadium in steel can effectively combine free nitrogen, and the combination of vanadium and nitrogen can be further Enhanced vanadium on the strengthening effect of steel, so some standards also indicate that "if there is enough nitrogen-bound elements exist nitrogen content can be higher than the standard requirements."


As the anchorage agent is a high-strength materials as aggregate, cementitious material as a binder, supplemented by high-flow micro-expansion anti-segregation and other substances from the preparation of its composition to inorganic materials, organic materials, supplemented, No rust effect. Therefore, in a few hours to produce a certain amount of anchoring force. With fast condensate, fast hard, high strength, no shrinkage, high shear strength, penetration resistance and other characteristics. The method is applicable to all mine roadway, tunnel, water conservancy, slope support and other projects within 3m within the rock support.

Mechanical behavior

The mechanical properties of the steel bars are determined by the test, and the mechanical properties of the steel bars are measured. The mechanical properties such as yield point, tensile strength, elongation and cold bending performance are measured.

Yield point (fy)

When the stress of the steel bar exceeds the yield point, the tensile force does not increase and the deformation is increased significantly, will produce a large residual deformation, the current value of the tensile force divided by the cross-sectional area of the steel bar to bear the unit area of the tensile force , Is the yield point σs °.