Cold-rolled ribbed steel bars are steel bars with two or three crescent-shaped surfaces formed by multiple cold-rolling of hot-rolled wire rods, one rib compression and elimination of internal stress.

APPLICATION EFFECT

Cold-rolled ribbed steel bars are the replacement products of cold-drawn low-carbon steel wires in prestressed concrete components. In cast-in-place concrete structures, they can replace Grade I steel bars to save steel. They are the better cold-processed steels of the same type. Its performance and application effect are as follows:

The mechanical performance indicators of LL550 grade in my country's national standard "Cold-rolled Ribbed Steel Bars" GB13788-2000 are formulated with reference to international standards and standards of developed countries. The tensile strength is 550Mpa, and the elongation is δ[_10] 8% (equivalent to δ[_5] of 12-13%) in accordance with the German standard. From the comparison of these two indicators, the standards of my country's cold-rolled ribbed steel bars are not lower than the international standards.

ADVANTAGES

Cold-rolled ribbed steel bars have the following advantages:

1. High steel strength, which can save construction steel and reduce project costs. Compared with hot-rolled round steel bars, LL550 grade cold-rolled ribbed steel bars can save 35%-40% of steel when used in cast-in-place structures (especially in roofs). If no hooks are used, the amount of steel saved will be even greater. According to the market price of steel, each ton of cold-rolled ribbed steel bars can save about 800 yuan in steel costs.

2. The bonding and anchoring performance between cold-rolled ribbed steel bars and concrete is good. Therefore, when used in components, the phenomenon of cracking in the anchoring area of the component and damage caused by wire slippage is fundamentally eliminated, and the bearing capacity and crack resistance of the component end are improved; in reinforced concrete structures, the crack width is also smaller than that of round steel bars, and even smaller than that of hot-rolled threaded steel bars.

3. The elongation of cold-rolled ribbed steel bars is larger than that of similar cold-processed steels.