1. Hot rolled Rebar:
HPB 235 level ф surface light round low carbon steel (bar, beam and column stirrup, trabecula, column main bar)
HRB Class 335 φ Surface ribbed (crescent/thread) ordinary low alloy steel (main reinforcement for beams and columns and main reinforcement for concrete walls)
HRB 400 ribbed crescents ordinary low alloy steel (main reinforcement for beams and columns and concrete walls)
RRB 400 Ribbed Herring/crescent plain low alloy steel (seldom used, poor plasticity for prestressed concrete)
– hot rolled H P – 235 – smooth B – steel yield strength/M 235 ㎡
R — Waste heat treatment R — ribbed
2. Cold-drawn reinforcement :(used for prestressed concrete)
With HRB335, HB400 at room temperature stretching.
3. Heat treated Rebar :(used in prestressed concrete with high strength)
It is made of ordinary low alloy steel after quenching and tempering.
1. Carbon steel wire: made of high carbon rolling.
2. Notch wire:
3. Steel strand: a bundle of carbon Rebar.
4. Cold-drawn low carbon Rebar
5. Cold rolled ribbed Rebar:
Strength and deformation of steel bars
A reinforcement bar with a distinct yield point :(mild steel)
1. Curve of stress σ — strain ε.
2. Mechanical index: yield strength; Ultimate strength; Elongation factor
When δ L reaches Max, the time becomes ξ
3. The yield strength of mild steel is used as the basis to determine the design strength of steel bar.
Reinforcement without obvious yield point :(hard steel)
No obvious yield point, high ultimate tensile strength, but poor plasticity.
For hard steel, the corresponding stress at 0.2% residual strain is assumed as the yield point (conditional yield point), =
0.8 is used as the conditional yield strength of rigid steel, which is used as the basis for determining the design strength of rigid steel.
Cold drawing/cold drawing can improve strength and save reinforcement. Cold drawing: can improve tensile and compressive strength.
Cold working will make the reinforcement brittle, so it is strictly prohibited to be used for precast component rings.