How to correctly identify true and false rebar!
Rebar is the common name for hot-rolled ribbed steel bars. 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 three words: hot-rolled (HotrolLED), ribbed (Ribbed), and steel (Bars). The hot-rolled ribbed steel bars are divided into three grades: Grade II HRB335 (the old grade is 20MnSi), Grade III HRB400 (the old grades are 20MnSiV, 20MnSiNb, 20Mnti), and Grade IV HRB500.
The unqualified factors of fake and inferior hot-rolled ribbed steel bars (commonly known as rebar) in the steel market are mainly: 1. The actual size is about one specification smaller than the nominal size. Profiteering. 2. The intensity is low. 3. High rate of unqualified chemical composition. The main reason is that the raw materials of the small rolling mill are unqualified, and the rebar is rolled with the steel billet made of soil.
When buying rebar, first look at the appearance size, you can use a vernier gauge to simply measure whether the actual size is smaller than the marked size (generally rebar is rolled with a specification mark) by about one specification or more (such as Ø12 rebar) The standard inner diameter is 11.5±0.4mm, while the inner diameter of fake rebar is mostly about 10mm). At the same time, some fake and inferior rebars deceive people’s vision by flattening them, so they are oblate when viewed from the end face of the steel bar, while the end face of the regular steel should be basically round; second, from the perspective of surface quality, the use of fake rebar is due to The adobe rolling has poor surface quality, often with defects such as scarring, and has an overall rough feeling. At the same time, some small rolling mills have a reddish surface due to insufficient heating temperature and rolling speed; third, the regular steel is mostly packaged in large bundles when the factory leaves the factory, and the bundles of steel are hung with metal signs corresponding to the physical objects to indicate the manufacturer. , Steel grades, batch numbers, specifications and inspection codes, etc. However, because of the crude production conditions and no large-scale hoisting equipment, the fake and inferior steel bars are mostly packaged in small bundles (about ten bundles) or in bulk, without metal signs and quality guarantees. Of course, it is necessary to avoid buying fake and inferior steel bars at all, or to buy from the direct agents of famous brand manufacturers, especially the famous brand steel bars in the province (the "Minguang" brand rebar of Sangang) is not only stable in quality, but also easy to handle even if disputes arise. . Experienced people can also distinguish other chemical components by sparks.
It is recommended that when purchasing rebar, users must go to a regular steel business unit or business point to purchase regular steel, obtain a steel quality certificate, and conduct an acceptance check. For those with quality doubts, you can go to a professional inspection agency for quality consultation and testing.