针对断面规格为250mm×250mm×9.2mm的Q345B厚壁冷弯方形型钢管,进行了平板、弯角、相应母材和短柱试件的力学性能试验。结合冷弯生产工艺,详细分析了平板、弯角试件力学性能随冷弯道次的变化规律,并与相关文献中的厚壁型钢冷作硬化效应作了比较。运用国内外冷弯型钢设计规范和相关文献中的修正规范,对本厚壁冷弯方形型钢全截面强度进行了设计和对比分析。结果表明:国外公式偏于危险,国内薄壁公式可直接用于该冷弯方形钢;型钢全截面上平板件的性能分布极不均匀,短柱全截面强度的提高远低于平板与弯角部分强度的提高。 Aiming at the Q345B thick-walled cold-formed square steel tube with cross-section specification of 250mm × 250mm × 9.2mm, the mechanical properties of the flat plate, the bending angle, the corresponding base metal and the short column specimens were tested. Combined with the cold-bend production process, the mechanical properties of the flat and curved specimens were analyzed in detail with the variation of cold-bend times, and compared with the cold-hardening effect of the thick-walled steel in related literatures. Using the design rules of cold-formed steel at home and abroad and the corrections in related literatures, the strength of full-section cold-formed square section steel is designed and compared. The results show that the foreign formula is partial to the danger and the domestic thin-walled formula can be directly used for the cold-formed square steel. The performance distribution of the flat-plate is not uniform on the full cross-section of the steel. Part of the increase in strength.