Q235B H-beams (yield 235MPa) are cost-effective but have limitations:
1) Low-temperature environments: They lack impact toughness at temperatures <0℃ (no low-temperature impact requirement in GB/T 11263), so they cannot be used in cold regions (e.g., northern China in winter) without additional treatment (normalization);
2) Heavy loads: Their low strength makes them unsuitable for high-rise building columns or heavy truck frames, where Q355B/Q460 are preferred;
3) Corrosive environments: Without anti-corrosion treatment (galvanizing, painting), they rust easily in coastal or industrial areas, limiting use in bridges or chemical plants.