Large diameter square tubes are long strips of steel with a hollow cross-section and no seams along the edges.

Large diameter square tubes are extensively used as pipelines for conveying fluids, such as for transporting oil, natural gas, coal gas, water, and certain solid materials. They are also widely employed in the manufacture of structural components and mechanical parts, including oil drilling rods, automotive drive shafts, bicycle frames, and steel scaffolding used in construction projects.