Classification of hot rolled steel bars

Introduction

Hot-rolled reinforcing steel bars are the most widely used load-bearing and load-bearing structures in construction engineering. It is widely used in bridges, large-scale long-span structures, tall buildings, small structures, high-rise steel structures, bridge support, fences and stents, and retaining walls. Therefore, the quality assessments and grades of hot-rolled reinforcing steel bars are of great importance. This article will discuss the classification criteria for hot-rolled reinforcing bars from different aspects.

Classification of hot-rolled reinforcing bars by diameter

Hot rolled reinforcing bars can be classified according to diameter. The sizes refer to the diameter of standard reinforcing bars and are also called diameters. According to the industry standard JG/T65-2011, steel bars divided into different diameters are listed in Table 1.

Table 1 Diameters of hot-rolled reinforcing bars

Diameter (mm) 6 8 10 12 14 16 18 20 22 25

Classification of hot-rolled reinforcing steel bars by aspect ratio

The aspect ratio of hot-rolled reinforcing steel bars is the ratio of its length to its width. Under normal circumstances, the quality test and grade of hot-rolled reinforcing steel bars are not only related to their diameter, but also related to their aspect ratio, which indicates the ratio of the length to the width of the steel bars. According to the classification of hot-rolled reinforcing steel bars in terms of aspect ratio, it is divided into three categories: short steel (length to width ratio is 12:5 or less), medium steel (length to width ratio is more than 12:5 and equal to or less than 23:10) and long steel (length to width ratio is more than 23:10).

Classification of hot-rolled reinforcing bars by strength

The strength of a hot-rolled reinforcing steel bar refers to the ability of a metal material to resist deformation under external forces. According to the classification of hot-rolled reinforcing steel bars by strength, it is divided into four grade categories: HRB 400-HRB 500, HRB 350-HRB 400, HRB 335-HRB 350, and HRB 320-HRB 335.

Conclusion

In summary, hot-rolled reinforcing steel bars can be classified by diameter, aspect ratio and strength. For hot-rolled reinforcing bars of diameter 6-25mm, only short steel, medium steel and long steel will emerge in terms of aspect ratio. In terms of strength, hot-rolled reinforcing bars are divided into four grade categories, namely HRB400-HRB500, HRB350-HRB400, HRB335-HRB350, and HRB320-HRB335. In conclusion, the actual choice of hot-rolled reinforcing bars should be based on the specific needs and characteristics of the structure when it is used, and should be determined based on the reasonable combination of these three aspects.

Hot-rolled steel bars, commonly known as steel bars, are widely used in reinforced concrete structures. Steel bars are usually divided into different grades according to their mechanical properties. Generally, the Division of rebar grades are shown as A, B and C.

Grade A rebar is made of low carbon steel and is the most common grade of steel bar used in construction. This kind of rebar is excellent for cold working, has good tensile strength, and can be bent and re-straightened without damage. Grade A bars are most suitable for large areas with fewer corners, since these bars can be curved up to 180° without negative effects on strength.

Grade B rebar is also made of low carbon steel and is made with a rib pattern to provide extra strength. This type of bar is more suitable for highly reinforced concrete structures, since it provides greater strength when used in conjunction with other bars. With the rib pattern and good ductility, Grade B rebar can generally be bent and re-straightened up to 90° without compromising strength.

Grade C rebar is the most commonly used grade in reinforced concrete structures. It is made with high tensile strength and ribbed to allow higher ductility and reduced stress concentrations. Grade C bars generally meet the requirements of ASTM A615-14, and can be bent to an angle of up to 45° without compromising strength.

As different rebar grades have different mechanical properties and suit different types of reinforced concrete structures, choosing the right grade for a structure is very important. To ensure the safety of a reinforced concrete structure, it is important to choose the right grade of rebar for the job.