Rebar commonly used classification method has two kinds: one is based on the geometric shape classification, according to the shape of the cross section of the cross rib and rib spacing to classify different or parting, such as the British standard (BS4449), will be divided into Ⅰ, Ⅱ rebar.This classification mainly reflects the grip performance of rebar.Second, the performance classification (level), such as China's current implementation standards, rebar for (G B1499.2-2007) wire for 1499.1-2008), according to the strength level (yield point/tensile strength) will be divided into three grades of rebar;Japanese industrial standard (JI SG3112), according to the comprehensive performance will be divided into five types of rebar;British standard (BS4461), also provides a number of grades of rebar performance test.In addition can also be classified according to the use of rebar, such as divided into reinforced concrete with ordinary steel and prestressed reinforced concrete with heat treatment steel.
1) Nominal diameter range and recommended diameter
The nominal diameter of the steel bar is 6 ~ 50mm, and the standard recommended nominal diameter of the steel bar is 6, 8, 10, 12, 14, 16, 20, 25, 32, 40, 50mm.
2) The surface shape and size of ribbed steel bars are allowed to deviate
The design principles of ribbed steel bars shall comply with the following provisions:
The Angle β of the transverse rib and the axis of the reinforcement should not be less than 45 degrees, when the Angle is not more than 70 degrees, the direction of the transverse rib on both sides of the reinforcement should be opposite;
Nominal rib spacing L shall not be greater than 0.7 times the nominal diameter of the steel bar;
The Angle α between the side of the transverse rib and the surface of the steel bar shall not be less than 45 degrees;
The sum of the gaps (including the width of the longitudinal ribs) between the upper transverse rib ends of the adjacent two sides of the reinforcement shall not be greater than 20% of the nominal perimeter of the reinforcement;
When the nominal diameter of reinforcement is not more than 12mm, the relative rib area should not be less than 0.055; nominal diameter is 14 mm and 16 mm, relative costal area should not be less than 0.060;When the nominal diameter is greater than 16mm, the relative rib area shall not be less than 0.065.The calculation of the relative rib area can be referred to Appendix C.
Ribbed bars usually have or do not have longitudinal ribs;
3) Length and allowable deviation
A, the length of the
The steel bar is usually delivered according to the fixed length, the specific length of delivery should be specified in the contract;
Steel coil can delivery, each dish should be a steel bar, allow 5% per batch plate number (less than two sets can have two sets) consists of two steel.The plate weight and plate diameter shall be determined by both parties through negotiation.
B. Allowable deviation of length
The allowable deviation of the length of the steel bar shall not be greater than ±25mm when delivered according to the fixed size;
When the minimum length is required, the deviation is +50mm;
When the maximum length is required, the deviation is -50mm.
C. Bend and end
The end of the steel bar should be shear straight, local deformation should not affect the use.
standard export packing (inside:water proof paper,outside:steel covered with strips and pallets)