搅拌针转速对6061-T6铝合金搅拌摩擦焊接头焊接温度及硬度分布的影响

Effect of Stirring Needle Rotation Speed on Welding Temperature and Hardness Distribution of 6061-T6 Aluminum Alloy Friction Stir Welded Joint

廖利华 ¹莫宇丹 ²刘克 ³张鹏 ²张文康 ²何洪²

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作者信息

1. 湖南汉能科技有限公司,株洲 412002;湖南大学机械与运载工程学院,长沙 410082
2. 湖南大学机械与运载工程学院,长沙 410082
3. 江麓机电集团有限公司,湘潭 411100
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摘要

通过试验研究了960～1 800 r·min-1搅拌针转速下6061-T6铝合金搅拌摩擦焊接头的硬度分布;采用ABAQUS软件对搅拌摩擦焊过程的温度分布进行有限元模拟,通过热影响区测温点的温度变化对模型进行验证,模拟研究搅拌针转速对热影响区焊接温度的影响,并建立焊接温度分布与接头硬度分布的对应关系.结果表明:接头最低硬度位于热影响区或焊核+热机影响区.当搅拌针转速不高于1 200 r·min-1时,后退侧最低硬度(RLH)区域的硬度低于前进侧最低硬度(ALH)区域,RLH区域为接头力学性能的最薄弱位置;当搅拌针转速高于1 200 r·min-1后,ALH区域的硬度低于RLH区域,ALH区域成为最薄弱位置.模拟得到热影响区不同测温点的温度变化趋势与试验结果相吻合,峰值温度的最大相对误差为2.6%,说明该模型可以准确预测6061-T6铝合金在搅拌摩擦焊接过程中的温度分布.当搅拌针转速不超过1 200 r·min-1时,RLH区域的峰值温度比ALH区域更高,析出相溶解更多,硬度更低;当搅拌针转速高于1 200 r·min-1后,ALH区域的峰值温度更高,在高温区域停留的时间更长,析出相溶解更严重,硬度更低.通过模拟获得接头焊接时峰值温度超过400℃且降温速率最慢的区域,即为接头力学性能的最薄弱位置.

Abstract

The hardness distribution of the friction stir welded joint of 6061-T6 aluminum alloy under the stirring needle rotation speed of 960-1 800 r·min-1 was studied.The finite element simulation of temperature distribution during friction stir welding was carried out by ABAQUS software,and was verified by the temperature change of the temperature measurement points in the heat affected zone.The influence of stirring needle rotation speed on the welding temperature in the heat affected zone was simulated and studied,and the corresponding relationship between the welding temperature distribution and the joint hardness distribution was established.The results show that the lowest hardness of the joint was located in the heat affected zone or the welding core+thermo-mechanically affected zone.When the rotation speed of the stirring needle was not higher than 1 200 r·min-1,the hardness of retreating side law hardness(RLH)region was lower than that of advancing side low hardness(ALH)region,and RLH region was the weakest position of the mechanical properties of the joint.When the rotation speed of the stirring needle was higher than 1 200 r·min-1,the hardness of ALH region was lower than that of RLH region,and ALH region was the weakest position.The temperature variation trend of different temperature measurement points in the heat affected zone was consistent with the test results,and the maximum relative error of the peak temperature was 2.6%,indicating the model could accurately predict the temperature distribution in friction stir welding 6061-T6 aluminum alloy.When the rotation speed of the stirring needle was no more than 1 200 r·min-1,the peak temperature in RLH region was higher than that in ALH region,resulting in more precipitates dissolving and lower hardness.When the rotation speed of the stirring needle was higher than 1 200 r·min-1,the peak temperature in ALH region was higher,the residence time in the high temperature region was longer,the precipitates dissolved more seriously,and the hardness was lower.The region where the peak temperature exceeded 400℃and the cooling rate was the slowest obtained by simulation was the weakest position of the mechanical properties of the joint.

关键词

焊接温度/搅拌针转速/析出相/硬度分布

Key words

welding temperature/stirring needle rotation speed/precipitate/hardness distribution

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基金项目

湖南省杰出青年科学基金资助项目(2024JJ2021)

国家自然科学基金资助项目(51975201)

出版年

2024

机械工程材料

上海材料研究所

机械工程材料

CSTPCD北大核心

影响因子：0.558

ISSN：1000-3738

参考文献量4

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