Hot-dip galvanized hollow structural sections - crack prevention and mechanical behaviour

热浸镀锌空心结构型材 - 裂纹预防和机械性能

• 批准号: 500838-2016
• 负责人: Sun, Min
• 金额: $ 1.46万
• 依托单位: University of Victoria
• 依托单位国家: 加拿大
• 项目类别: Collaborative Research and Development Grants
• 财政年份: 2017
• 资助国家: 加拿大
• 起止时间: 2017-01-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=618087
• 关键词: Hot; dip; galvanized; hollow; structural

The application of hot-dip galvanized cold-formed Hollow Structural Sections (HSS) in exposed steelstructures (e.g. bridges, transmission towers and sign supporting structures) is extremely popular due to theirsuperior strength-to-weight ratio, low initial cost, sustainability and aesthetics. Both HSS manufacturing andhot-dip galvanizing techniques have evolved over the years. However, the use of newly developed zinc bathmixtures together with thick-walled HSS resulting in significant damage in the latter in the form of crackingduring the galvanizing process, especially at comer regions of Rectangular Hollow Sections (RHS), has beenreported to be a widespread problem lately. In an even worse case, if such cracks do not cause visible damage to the section and remain undetected before the final product leaves the galvanizing shop, they can result in serious consequences on the performance of the structure. This research aims to investigate: (1) the prerequisites of cracking; (2) if hot-dip galvanizing-induced embrittlement is a concern for RHS with different cross-sectional dimensions and produced to different specifications; (3) the thresholds of wall thickness above which different levels of pre-galvanizing countermeasures for brittle cracking are needed; and (4) the detrimental/beneficial effects of hot-dip galvanizing on the mechanical behaviours of RHS.The long-term goals of this project are to: (1) provide guidelines to engineers, fabricators and galvanizers to minimize the risk of cracking in RHS during hot-dip galvanizing; (2) generate supplemental rules to HSS manufacturing specifications and crack control guidelines; and (3) provide a better understanding of the characteristics and structural performance of hot-dip galvanized RHS to facilitate its application.

热浸镀锌冷弯空心结构型材 (HSS) 在裸露钢结构（例如桥梁、输电塔和标志支撑结构）中的应用因其优越的强度重量比、较低的初始成本、可持续性和美观而非常受欢迎。高速钢制造和热镀锌技术多年来都在不断发展。然而，据报道，新开发的锌浴混合物与厚壁高速钢一起使用，导致后者在镀锌过程中以开裂的形式出现严重损坏，特别是在矩形空心型材 (RHS) 的角部区域，这是一个普遍存在的问题最近。在更糟糕的情况下，如果此类裂纹不会对部件造成明显损坏，并且在最终产品离开镀锌车间之前仍未被发现，则可能会对结构的性能造成严重后果。本研究旨在探讨：（1）破解的前提条件； (2)对于不同截面尺寸、不同规格生产的RHS是否存在热镀锌脆化问题； (3)壁厚阈值，超过该阈值需要采取不同程度的预镀锌脆裂对策； (4) 热浸镀锌对 RHS 机械行为的有害/有益影响。该项目的长期目标是：(1) 为工程师、制造商和镀锌商提供指导，以最大程度地减少 RHS 中开裂的风险。热镀锌过程中的RHS； (2) 生成高速钢制造规范和裂纹控制指南的补充规则； (3)加深对热镀锌RHS的特点和结构性能的了解，以利于其应用。