Rebar is a common name for hot rolled ribbed bars. The grade of ordinary hot-rolled steel bars consists of the minimum value of the yield point of HRB and the grade. H, R, and B are the first letters of the English word for hot rolling (HotrolLED), ribbed (Ribbed),steel coil ppgi and steel bars (Bars). Hot-rolled ribbed steel is divided into two grades: HRB335 (old grade 20MnSi), third grade HRB400 (old grade 20MnSiV, 20MnSiNb, 20Mnti) and four grade HRB500.
The unqualified factors of the shoddy hot-rolled ribbed steel bars (commonly known as rebar) in the steel market are mainly as follows: 1. The actual size is smaller than the nominal size by one specification. The dealer purchases the actual weight, and the theoretical weight delivers the metal amount. Profiteering. 2. The intensity is low. 3. The chemical composition failure rate is high. The main reason is that the raw materials of small rolling mills are unqualified, and the steel slabs are used to roll rebar.
When purchasing rebar, first of all, from the appearance size, you can use the vernier card gauge to simply measure whether the actual size is about one size or more smaller than the specified size (the general rebar has a specification mark) (such as Ø 12 rebar The standard inner diameter is 11.5±0.4mm, while the inner diameter of the shoddy rebar is mostly about 10mm). At the same time, some counterfeit rebars deceive the human vision by flattening, so they are oblate from the end face of the steel bar, and the end face of the regular material should be basically round; secondly, from the surface quality, the counterfeit rebar is used.
For adobe rolling, the surface quality is poor, often with defects such as scars, and overall roughness. At the same time, some small rolling mills have insufficient heating temperature and rolling speed, and the surface color is reddish. Thirdly, the regular steel is mostly bundled in the factory when the factory leaves the factory. The metal signs corresponding to the real objects are hung on the bundled steel, indicating the manufacturer. , steel grade, batch number, specifications and inspection code.
However, due to the poor production conditions, there are no large hoisting equipment, most small bundles (ten bundles) are packaged or bulk, no metal signs, no quality guarantee. Of course, we must avoid buying fake steel bars at all, or buy them from the direct agents of famous brand manufacturers, especially the famous brand steel bars in the province, which is not only stable in quality, but also easy to handle even if disputes occur. . Experienced people can also discriminate other chemical components through sparks.
It is recommended that when purchasing rebar, users must purchase regular steel products from regular steel business units or operating points, obtain steel quality certificates, and conduct inspection and acceptance. For quality assurance, you can go to a professional inspection agency for quality consultation and testing.