Coiled rebar is one of the steel products used in various industries. This product is a subset of the rebar product that is sold in coils or in other words wire. Usually, the difference of this product with ordinary rebar, has also distinguished its applications.

Using coil bars, reinforcement can be designed in the building. Since the tensile strength of concrete is very low compared to its compressive strength, reinforcement is used to increase its tensile strength.

Rebars are presented to the market in two modes: branch and coil. Rebars of smaller sizes can be wrapped in coils, as less rebar diameters help make it more flexible. In summary, the advantages of a rebar coil include lower volume, easier transportation and warehousing. But read more in that article.

What is Coiled Rebar?

Coiled rebar is actually a final steel product (alloyed or non-alloyed) that is produced through rolling operations on semi-finished products such as ingots, slabs or blooms. With cold stretching, you can achieve a suitable cross-section of this product. After production, this product is in the form of a rebar, after being cut into a branch, it is wrapped in a coil and transported in the same way.

Coiled Rebar Production Process

First, they prepare the raw materials in the factory, which are steel ingots. The constituent elements of these ingots should consist of carbon, silicon, manganese, phosphorus and sulfur. The first stage of the coiled rebar production process is preheating the steel ingots in thermal furnaces to a temperature of 1100 degrees Celsius. The next step will be to transfer the ingots to the roughing section by the furnace rolls. After the roughing stage, the turn will come to the hot rolling stage. At this stage, because the amount of plastic stress is low; Annealed ingots are passed through several rows of rollers and their diameter is reduced during three continuous deformation stages. After the rolling stage is finished, the rebar is wrapped around a ring and transferred to the cooling unit. In the figure below, you can see a schematic of the coiled rebar production process.

Familiarity with types of Coiled Rebar

Coil bars are divided based on two methods.

The first method, like the branch rebar, is based on its being plain and reinforcement. Plain coil and reinforced coil are produced in different standards. Coiled rods are usually produced in 5.5 to 16 mm sizes and distributed in the market. A plain coil with dimensions of 5.5 to 8 mm is also called wire.

Reinforced Coil

This type of small size rebar is produced similar to branch rebars in A2 and A3 standards. The price of the reinforced coil in these two standards is similar to the price of the rebar. Reinforced coils are produced in Kashan Kavir Steel, Aligudarz Steel, Ahramian steel in Yazd, Natanz steel, Kausar steel in Ahvaz, Golestan steel and Shiraz steel.

Plain Coil

The use of plain coils in buildings causes uniform distribution of forces from loads on the roof. The types of simple coiled bars according to the standards are:

• 5.5 coil simple RST34 rebar
• 5.6 simple coil RST34 rebar
• RST34 simple 8 coil rebar
• Rebar of 10 simple coils RST34

The second method of classifying coiled rebars is based on the amount of carbon in the rebar. In the following, we will get to know more about this category.

Low Carbon Wire Rod or Coil

This type of rebar has the ability of high elasticity, flexibility, weldability and cold rolling due to having a small percentage of carbon in the structure. Two standard types of rebar coils are used in this category. The standard is SEA1006 and SEA1008. The chemical composition table of this type of low carbon coil is given below:

CHEMICAL ANALYSIS
%S (max)	%P (max)	%Mn	%Si (max)	%C (max)	Grade
0.04	0.05	0.25-0.4	0.15-0.25	0.08	SAE 1006
0.04	0.05	0.3-0.5	0.15-0.25	0.1	SAE 1008
MECHANICAL PROPERTIES
Yield Strength (MP)	Ultimate Strength (MP)	Hardness (HB)	Elongation (%)	Diameter (mm)	TEST RESULTS
230	343	90-120	%31	6.50

Medium Carbon Wire Rod or Coil

This product is used as a raw material in factories. Medium carbon coiled rebar in the form of wire has many applications for making springs, tow wires, electric cables and tire industries. This type of coil is produced in RST34 and RST37 standards. The following table shows the chemical analysis of this product:

CHEMICAL ANALYSIS
%S (max)	%P (max)	%Cr	%Mn	%Si (max)	%C (max)	Grade
0.04	0.05	0.01-0.014	0.5-0.8	0.04-0.07	0.11-0.16	RST34
0.04	0.05	0.01-0.014	0.6-0.8	0.04-0.07	0.12-0.18	RST37

High Carbon Wire Rod or Coil

This product has a high percentage of carbon (more than 0.44%). This high percentage of this type of rebar has reduced its flexibility and elasticity. The uses of this product are like medium carbon coils.

Application of Coiled Rebar

Coiled bars or wires are used in a wide range of products depending on the type of shape they have. The main applications of wire are given below:

• Use in making steel mesh
• Manufacturing bolts
• Use in the manufacture of springs
• Can be used as a tow wire
• Use as wire rope
• Can be used in electrode and welding industries
• In the construction industry, coiled rebar is used to strengthen the strength of concrete structures, fireproof blocks, gas connections and columns.

What is the Shape and Size of the Wire?

Wire rod is a finished steel product that is formed by cold rolling for further processing. Although this product has different shapes, it is mainly shaped as a circle. The diameters are usually from 5 to 15 mm and most of them comply with ISO standards. The inner diameter of the wire usually varies from 810 to 910 mm and its outer diameter from 1100 to 1300 mm (depending on the equipment of the manufacturing plant). Subsequently, the weight of wire rope varies from approximately 600 kg and greater than 2 tons.