HRB400 Meaning?

What does Steel Rebars hrb400 mean? How to select Rebar?

HRB400 Chinese name is hot rolled ribbed bar, diameter is 6 ~ 100mm. National mandatory standard GB1499.2 -- 2007 "reinforced concrete with hot rolled ribbed bar" from March 1, 2008 began to implement. The standard yield strength of the steel bar HRB400 is 400MPa, and the design value is 360MPa.

1, HRB is hardness value, means hot-Rolled ribbed -steel Bar Hot rolled Ribbed bar, refers to the Rockwell hardness measurement (HR) class B scale, represents the hardness of the steel being measured how many HRB, the number after is the yield strength of the bar.

2, Third grade Rebars (HRB400 above) is also threaded Steel Rebars, similar to the diameter of Second grade Steel Rebars, higher strength, but the price is also high, has been gradually promoted.

3. Secondary steel bar (HRB335) is threaded steel bar, the diameter of 12-25 is the most common, used in beams, columns, shear walls and so on. No matter how large the diameter is, it is rarely used in civil and industrial construction. It is often used in mass concrete, such as hydraulic engineering.

4, The first grade steel bar (HPB300) is generally smooth steel, belonging to the hot rolled round steel bar, commonly known as wire rod, 6-12 rounds of the most common. In architecture, it is often used to make stirrups, distribution bars of plates, stirrups, wall reinforcement and so on.

Hot-rolled ribbed steel bar is commonly known as threaded steel bar, usually with two longitudinal ribs and transverse ribs evenly distributed along the length. The shape of the transverse ribs is spiral, herringbone, and crescent. The current Chinese standard stipulates that it is crescent. The nominal diameter of the steel bar is 6~50mm. Ribbed steel bars mainly bear tensile stress in concrete, and due to the effect of the ribs, they have a greater bonding ability with concrete.

 

 

 

►High strength: HRB400 steel bars have high yield strength and ultimate strength and can withstand large loads.

►Good ductility: Even when the yield point is exceeded, the steel bars will not break immediately and have a certain plastic deformation capacity.

►Hot rolling process: Produced through the hot rolling process, the steel bars have ribs on the surface, which increase the bonding strength between the steel bars and concrete, thereby improving the overall performance of reinforced concrete structures.

The main difference is that HRB400E has seismic standards. All steel bars with seismic standards are collectively referred to as E-bars.

Here, HRB400E refers to a strength level of 400MPa with seismic performance. In addition, the key to this type of steel bar is that the super-yield ratio index cannot be too large and the elongation cannot be too small.

Chinese steel bars have experienced a process of development from low strength to higher strength.

1.High-rise buildings:Due to thei high strength and good ductilty,HRe400 steel bars are suitable for key parts such as columns and begms in hich-risebuildings.

2. Bridge engineering:in the construction of bridges,HRB400 steel bars can provide the necessary tensie strenath to ensure the stobility and sofety of thebridge structure.

3.infrastructure:HRB400 steel bars are also used in the construction ofinfrastructure such as roads and tunnels to meet the requirements of structural strenath and stability.

HRB400 steel bar is a steel bar with poor weldability. According to the data in the composition table above, the carbon equivalent of HRB400 steel is ≤0.54%, but the actual carbon equivalent of the steel mill can be controlled at 0.4% at present.

According to our many years of production experience, when the carbon equivalent in carbon steel and alloy steel is not more than 0.4%, the weldability of the steel is good; when the carbon equivalent is between 0.4% and 0.6%, the hardening tendency of the steel increases, and preheating and control of welding parameters are required during welding; when the carbon equivalent is greater than 0.6%, the hardening tendency of the steel is strong, and it is difficult to weld steel, and a higher preheating temperature, post-weld heat treatment, and strict process measures are required.

Compared with Q235 steel, HRB400 steel adds a surface quenching process to make the surface corrosion resistance of steel better; at the same time, adding tempering process makes the composition of steel more uniform, reducing the possibility of potential difference between different organizations making steel easy to corrode. Therefore, the corrosion resistance of HRB400 steel is better than that of Q235 steel.

In summary, the HRB400 steel bar, as a high-strength and high-ductility hot-rolled ribbed steel bar, plays an important role in various construction projects. Its unique production process and wide range of applications make it one of the indispensable and important materials in the construction industry.

Xi'an Dongmeng Steel Co., Ltd.

 

Xi'an Dongmeng Steel Co., Ltd. is a well-known enterprise in the international steel market.which is certifed by SGS Group.lt focuses on providing high-quality steel bars,Since its establishment, the company has been committed to providing customers with high-quality coiled steel rebar and other steel products, which are widely used in various civil engineering fields such as construction, bridges, roads, and tunnels. constantly pursuingexcellence and innovation, and committed to building a world-eading steel supply chainservice system.