Hot rolled ribbed steel bars are divided into three grades: Grade II HRB335 (old brand name 20MnSi), Grade III HRB400 (old brand names 20 mnsi, 20MnSiNb and 20Mnti) and Grade IV HRB500.
The surface quality of steel bars is stipulated in relevant standards, which requires that the ends be cut straight, and the surface shall be free of cracks, scars and folds, and there shall be no harmful defects in use.
Extended data:
GB 1 499.2-2007/XG1-2009 National StandardNo.1for Steel for Reinforced Concrete Part 2: Hot Rolled Ribbed Reinforcement; GB/T 2 10 1—2008 (General Provisions on Acceptance, Packaging, Marking and Quality Certificate of Section Steel); Gb1499.5438+0 ~ GB1499.3 (reinforcement for concrete); JIS G3 1 12—87(98) (rebar for reinforced concrete); JIS G3191-66 (94) (shape, size, weight and allowable deviation of hot rolled bars and coils); BS 4449-97 (Hot rolled steel bars for concrete structures).
The sum of the end gaps of transverse ribs (including the width of longitudinal ribs) on the adjacent sides of the steel bar should not be greater than 20% of the nominal circumference of the steel bar; When the nominal diameter of reinforcement is not greater than 12mm, the relative rib area should not be less than 0.055; When the nominal diameters are 14mm and 16mm, the relative rib area should not be less than 0.060; When the nominal diameter is greater than16mm, the relative rib area should not be less than 0.065.
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