Classification and application of threaded reinforcement
1. The meaning of threaded steel bars
Threaded steel bar is the common name of hot rolled ribbed steel bar. The grade of ordinary hot-rolled steel bar is composed of HRB and the minimum yield point of the grade. H, R and B are the first letters of the words Hotrolled, Ribbed and Bars respectively. Hot rolled ribbed steel bars are divided into two grades HRB335(old number 20MnSi), three grades HRB400(old number 20MnSiV, 20MnSiNb, 20Mnti) and four grades HRB500.
A threaded bar is a bar with a ribbed surface, also known as a ribbed bar, usually with two longitudinal ribs and transverse ribs evenly distributed along the length. The shape of the transverse rib is spiral shape, herringbone shape and crescent shape. Widely used in the construction of houses, Bridges, roads and other civil engineering, it is a must for medium and above building components.
2. Classification of threaded steel bars
There are two common classification methods for threaded rebar:
The first is to classify the geometric shape, according to the cross-section shape of the ribs and the spacing of the ribs are different classification or classification, such as the British standard (BS4449), the threaded steel bar is divided into type I and type II. This classification method mainly reflects the grip performance of the threaded steel bar.
The second is the performance classification (grade), for example, China's current implementation standard, threaded bar is (G B1499.2-2007) wire is 1499.1-2008), according to the strength level (yield point/tensile strength) the threaded bar is divided into 3 grades; According to the Japanese Industrial standard (JISG3112), the threaded steel bar is divided into 5 types according to the comprehensive performance; The British standard (BS4461) also specifies a number of grades of threaded steel bar performance tests.
In addition, it can also be classified according to the use of threaded steel bars, such as ordinary steel bars for reinforced concrete, prestressed steel bars, heat treated steel bars for concrete, etc.
3. Specifications of threaded steel bars
In general, the specifications of the threaded steel bar should include the standard grade, the nominal diameter of the steel bar, the nominal weight that is, the quality, the specified length and the tolerance value of the above indicators. The nominal diameters recommended by the threaded bar standard are 6, 8, 10, 12, 16, 20, 25, 32, 40, 50mm. The supply length of threaded rebar is divided into two kinds of fixed length and double length. The selection range of threaded rebar for export in China is 6~12m.
4. Application of threaded reinforcement
Threaded steel bars are widely used in building, bridge, road and other civil engineering construction. Large to highways, railways, Bridges, culverts, tunnels, flood control, DAMS and other public facilities, small to the foundation of housing construction, beams, columns, walls, plates, threaded steel bars are indispensable structural materials.
