Research on Shear Bearing Capacity of High-Strength Bolted Connections of Weathering Steel Based on Crevice Corrosion
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摘要: 钢连接结构在长期服役过程中面临着严重腐蚀失效问题,缝隙腐蚀对连接结构抗剪承载力具有显著影响。对6个由Q355GNH耐候钢板和6个由Q355B普通钢板组成的高强度螺栓连接件开展乙酸盐雾加速腐蚀试验,将在腐蚀过程中清理连接板件摩擦面缝隙侧面处锈层与保留此处锈层获得的腐蚀连接件进行了对比分析,研究了连接件摩擦面的缝隙腐蚀行为及其对抗剪承载力的影响规律。结果表明:连接件摩擦面缝隙腐蚀产生的黑色腐蚀产物的增加可使抗滑移系数μ增大;耐候钢试件摩擦面缝隙侧面处的致密锈层阻滞氧气促进低氧缝隙腐蚀,去除此处锈层的试件摩擦面黑锈减少,平均滑移荷载下降了29.2%;普通钢试件摩擦面缝隙腐蚀黑色产物均较多,且清理摩擦面缝隙侧面处锈层的普通钢试件相较于不清理此处锈层试件的平均滑移荷载存在提高;缝隙腐蚀通过改变螺栓连接件摩擦面粗糙度减缓了由预紧力损失引起的螺栓连接件抗滑移承载能力的下降。
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关键词:
- Q355GNH耐候钢 /
- 高强度螺栓连接 /
- 缝隙腐蚀 /
- 抗剪承载力
Abstract: The connection structure of metal materials faces serious corrosion failure during long-term service, and the crevice corrosion has a significant impact on the shear bearing capacity of the connection structure. 6 high-strength bolted connectors composed of Q355GNH weathering steel and 6 high-strength bolted connectors composed of Q355B low-carbon steel were tested for accelerated corrosion in acetic acid salt spray. The corroded connectors with the rust outside the gap were used as the control group, and the rust outside the gap of the connecting plate was continuously cleaned during the corrosion process to study the crevice corrosion behavior, as well as the influence of crevice corrosion on the shear bearing capacity of the bolted connectors. The results showed that the anti-slip coefficient μ of the friction surface of the connector increased accordingly with the increase of the proportion of black rust. The rust produced by the weathering steel were dense, which could prevent oxygen to promote the low-oxygen crevice corrosion reaction, after removing the rust outside the gap, the black rust on the friction surface were reduced and the slip load was reduced by 29.2%. Whether the outer rust of the gap was removed or not, the crevice corrosion degree of the low-carbon steel bolted connectors was large, but the low-carbon steel connection that cleaned the outer rust of the gap had greater slip load through changing the roughness of friction surface of bolted connectors, crevice corrosion slowed down the decrease of anti-slip bearing capacity of bolted connectors caused by preload loss. -
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