以熔射覆膜技術提升摩阻型螺栓接合之滑移係數

Increasing slip coefficient of bolted slip-critical joints using thermal sprayed coating technique

陳誠直(Cheng-Chih Chen) ； 謝宗成(Tsung-Cheng Hsieh) ； 張誠(Cheng Chang) ； 李思維(Sui-Wei Lee)

《結構工程》 35卷4期 (2020/12) Pp. 5-18

https://doi.org/10.6849/SE.202012_35(4).0001

摘要

摩阻型螺栓接合之設計理念為利用高強度螺栓鎖緊時，螺栓之預拉力將於接合鋼板上產生夾緊力，此夾緊力將進一步產生鋼板間的摩阻力。因此摩阻型接合將可提供螺栓剪力方向的抗剪強度，此抗剪強度與螺栓的夾緊力與鋼板間的滑移係數有關。本研究目的在探討以熔射覆膜技術於鋼板摩擦面上覆膜，提升摩阻型螺栓接合的滑移係數。實驗計畫設計試體以探討熔射覆膜材料（純鋁、鋁鎂合金）、覆膜厚度（150、300與450 μm）及鋼板鏽蝕對滑移係數之影響。實驗結果顯示，鋼板接合面之鏽蝕可提升滑移係數。於些微鏽蝕情況下，鋼板接合面僅噴砂未覆膜之平均滑移係數為0.74，純鋁覆膜之平均滑移係數為0.88，鋁鎂覆膜之平均滑移係數亦為0.88，皆高於設計規範中鋼板去除黑皮未塗裝表面之滑移係數0.33。熔射覆膜材料與覆膜厚度於滑移係數無顯著影響，但於鏽蝕情況下隨著覆膜厚度的增加會造成滑移發生後螺栓預力損失的提高。於鋼板接合面施以熔射覆膜鋁或鋁鎂合金，可提升摩阻型螺栓接合之滑移係數，增加摩阻型接合強度，達到減少接合尺寸及螺栓數量。

關鍵字

摩阻型接合 ； 熔射覆膜 ； 滑移係數

並列摘要

The design philosophy of slip-critical joints is to utilize the friction force developed through the clamping force exerted by the pretension of the high-strength bolt. Thus, the slip-critical joint can have resistance in the direction of the bolt shear. This resistance is affected by the bolt clamping force and slip coefficient on the faying surface. The objective of this study is to increase the slip coefficient of bolted slip-critical joints by applying a thermal sprayed coating on faying surface. The specimens were designed to explore the effects of the coating material (aluminum or aluminum-magnesium alloy), coating thickness (150, 300 and 450 μm), and corrosion on the steel plate on the slip coefficient. The test results showed that exist of the rust increased the slip coefficient. In the case of slight corrosion, the blasted-cleaned faying surface resulted in an average slip coefficient of 0.74. The average slip coefficient was 0.88 for either the aluminum or aluminum-magnesium coatings. These slip coefficients are higher than the slip coefficient of 0.33 for unpainted clean mill scale specified in the design code. The coating material and thickness had insignificant effect on the slip coefficient. However, in the case of corrosion, the bolt pretension loss at slip was increased when the coating thickness was increased. The thermal sprayed coating of either aluminum or aluminum-magnesium on the faying surface can enhance the slip coefficient, increase the resistance of the slip-critical joint, and result in a smaller joint size and less high-strength bolts.

並列關鍵字

Slip-critical joint ； thermal sprayed coating ； slip coefficient