( 1. 江苏科技大学 材料科学与工程学院, 镇江 212003; 2.洛阳船舶材料研究所, 洛阳 471039)
摘 要: 通过5A30铝合金不同焊缝形式、 几何尺寸对接接头疲劳试验, 以及焊缝余高存在时焊趾处的应力集中系数的测定和理论计算, 研究了焊缝几何特征对铝合金焊接接头疲劳性能的影响。 结果表明: 单面焊双面成型和双面焊对接接头的疲劳性能相当, 在循环次数为(1.7~1.8)×106时, 疲劳强度约为100 MPa; 焊缝余高的存在使接头的疲劳性能明显降低, 增大焊缝余高, 接头疲劳性能显著下降, 去除余高, 则可使接头的疲劳寿命提高2~3倍; 厚度为4 mm板材对接接头, 焊缝余高为1~2 mm时, 焊趾处的应力集中系数较其他部位增大50%左右, 焊缝余高大于3 mm, 焊趾处的应力集中系数可超过1.70。
关键字: 铝合金; 焊接接头; 焊缝余高; 疲劳性能
5A30 aluminum alloy welded joints
( 1. School of Materials Science and Engineering,
Jiangsu University of Science and Technology,
Zhenjiang 212003, China;
2. Luoyang Ship Material Research Institute,
Luoyang 471039, China)
Abstract: Based on the fatigue testing of 5A30 aluminum alloy welded butt joints which have different weld types and geometrical dimensions, the measurement and calculation of stress concentration coefficients (Kt) at the toes of weld, the influence of weld geometrical features on fatigue properties of 5A30 aluminum welded joints was studied. The results show that the fatigue properties of single-welded butt joints and doublewelded butt ones are matched and the fatigue strength of theirs at (1.7-1.8)×106 cycle is about 100MPa. The presence of weld reinforcements (WRs) reduces the fatigue properties of welded joints. Heightening WRs can greatly lower the fatigue properties of welded joints and wiping out WRs can increase fatigue life twice or three times as much. When the weld reinforcements change between 1-2 mm, Kt at toes of weld of 4 mm thick plates are increased 50% comparing with other parts, and if the WRs is higher than 3 mm, Kt at weld toes of joints may exceed 1.70.
Key words: aluminum alloy; welded joint; weld reinforcement; fatigue property