B500A vs B500B vs B500C: Reinforcing Steel Grades Compared

When buyers compare B500A vs B500B vs B500C, the question is almost always about ductility. All three are 500 MPa reinforcing steels under EN 10080 and DIN 488 — the “500” in each name is the characteristic yield strength in megapascals. What separates the grades is their ductility class: how much they can stretch and how much the steel hardens past yield before it breaks. That property decides where each grade can safely be used, from lightly loaded mesh through to seismic-resistant frames. This guide explains each grade and sets out a clear comparison table.

B500A vs B500B vs B500C: the comparison table

The three grades are distinguished by two ratios measured in tensile testing: k = Rm/Re (the ratio of tensile strength to yield strength, a measure of strain hardening) and Agt (the total elongation at maximum force, a measure of ductility). Higher values mean a tougher, more deformable steel.

B500A — normal ductility

B500A is the normal-ductility grade, with k ≥ 1.05 and Agt ≥ 2.5%. It is commonly produced by cold rolling and supplied as coil and welded mesh in smaller diameters. Because its strain-hardening and elongation are modest, B500A is used where ductility demand is low — typically welded fabric for slabs and screeds, and light secondary reinforcement. It is efficient and economical for mass-produced mesh products. See our guide to reinforcing mesh sizes for where B500A mesh is applied.

B500B — high ductility (the workhorse)

B500B is the high-ductility grade and the everyday workhorse of reinforced concrete. With k ≥ 1.08 and Agt ≥ 5.0%, it offers a strong balance of strength and deformation capacity, which is why it is the default specification for beams, columns, slabs, foundations and most general structural work. B500B is hot-rolled as straight bar in diameters from 8 to 40 mm. For a full treatment of its properties and applications, read what is B500B rebar, and explore the product range on our B500B reinforcing steel pillar page.

B500C — seismic-grade ductility

B500C is the seismic grade, engineered for the highest ductility demand. Its strain-hardening ratio sits within a controlled band of 1.15 ≤ k < 1.35 and its elongation Agt is at least 7.5%. The upper bound on k matters in seismic design: it ensures the steel does not over-strengthen unpredictably, so plastic hinges form where the engineer intends. B500C is specified for structures in earthquake zones and other applications with severe cyclic or impact loading. It is hot-rolled bar, like B500B.

How to choose the right grade

Specify B500A where ductility demand is low and mesh is the natural product (slabs, screeds, blinding). Specify B500B for the great majority of cast-in-place reinforced concrete — it is what most Eurocode 2 designs assume. Specify B500C where the design code requires seismic detailing or high ductility. The German legacy designation BSt 500 S corresponds broadly to the modern high-ductility ribbed bar. Whatever the grade, every consignment we supply ships with a Mill Test Certificate to EN 10204 3.1 confirming the actual mechanical results.