What a Hot-Rolled H Beam Is
A hot-rolled H beam is a universal structural section produced in one piece in the rolling mill, with two parallel flanges and a connecting web forming an H-shaped cross-section. Because the flanges carry most of the bending stress, the H profile gives an excellent strength-to-weight ratio and is the most widely used section for columns and beams in steel buildings.
Grade Selection: Q235B and Q355
Q235B (GB/T 700): minimum yield strength 235 MPa and tensile strength 370-500 MPa for thickness up to 16 mm; an economical grade for light and medium frames.
Q355 (GB/T 1591): minimum yield strength 355 MPa and tensile strength 470-630 MPa for thickness up to 16 mm; the higher-strength grade that has replaced Q345 and is preferred for primary members in large buildings.
Both grades weld well with conventional processes, and the B suffix on Q235B requires a Charpy V-notch impact test of 27 J at 20 degrees C.
Standard Size Range
Hot-rolled H beams to GB/T 11263 cover sections from 100 x 100 x 6 x 8 mm up to 900 x 300 x 16 x 28 mm, together with column sections and wide-flange profiles. The four figures describe height, flange width, web thickness and flange thickness. Standard lengths are 6 m, 9 m and 12 m, and the theoretical mass per metre is listed in the standard for each section.
Dimensional Tolerances
GB/T 11263 limits deviations in height, flange width, web off-centre, thickness and length, with straightness typically within 0.1 percent of the beam length. The flat parallel flanges simplify bolted and welded connections, and the section constants needed for design are tabulated in the standard.
Applications in Construction
Columns and primary beams in portal frames and high-rise frames
Roof trusses, crane girders and industrial plant structures
Mezzanine floors, bridges and heavy equipment supports
Prefabricated and modular steel buildings
Frequently Asked Questions
Q: What is the difference between Q235B and Q355 H beams?
Q355 has a higher minimum yield strength of 355 MPa compared with 235 MPa for Q235B, so smaller sections can carry the same load, reducing steel weight and foundation cost.
Q: What does a size like 200 x 200 x 8 x 12 mean?
The figures give height 200 mm, flange width 200 mm, web thickness 8 mm and flange thickness 12 mm, which fully define the H beam section.
Q: What standard covers hot-rolled H beam dimensions in China?
GB/T 11263 specifies the dimensions, tolerances and theoretical weights of hot-rolled H and T sections, while material grades follow GB/T 700 or GB/T 1591.
Q: What lengths are standard for H beams?
Standard lengths are 6 m, 9 m and 12 m, and longer pieces can be arranged for special spans subject to transport limits.
Q: Can H beams be delivered with mill certificates?
Yes, every bundle is supplied with a mill certificate stating heat number, chemical composition and mechanical test results for full traceability.