6061铝合金薄板FSW接头组织和力学性能分析

利用搅拌摩擦焊(FSW)技术对1 mm厚的6061-T6铝合金薄板进行拼焊,研究FSW工艺参数对焊接头组织和力学性能影响。结果显示,FSW工艺参数对接头的金相组织和力学性能有显著影响。最佳焊接工艺参数为搅拌头旋转速度为15000 r/min,搅拌头前进速度为300 mm/min,其获得的接头抗拉强度为247 MPa,达到母材的74.8%;伸长率为5.3%,达到母材的41.1%。     

焊接速度对5754铝合金FSW接头微观组织和力学性能的影响

对3 mm厚的5754铝合金板材进行搅拌摩擦焊接，研究了搅拌头在转速800 r/min条件下，不同焊接速度(100 ~ 400 mm/min)对搅拌摩擦焊接头微观组织和力学性能的影响. 结果表明，5754铝合金FSW接头横截面形貌呈“盆”形. 随着焊接速度增加，5754铝合金FSW接头的焊核区和轴肩区的面积逐渐减小，而搅拌针区面积先增加后减小. 当焊接速度为300 mm/min时，搅拌针区面积达到最大值6.66 mm2，轴肩区和搅拌针区面积比例为0.97，5754铝合金FSW接头的强度系数达到97.5%，这主要是因为轴肩区和搅拌针区面积相近，增大了焊核区和热影响区界面面积，从而提高了FSW接头强度，拉伸断裂在焊核区以外(热影响区或基材区)，断口为韧性断口. 当焊接速度为400 mm/min时，5754铝合金FSW接头的强度系数为58.8%，拉伸试样均断裂在焊核区，断口为脆性断口.     

22mm 6061-T6铝合金板的搅拌摩擦焊接

采用搅拌摩擦焊(FSW)方法对厚度为22mm的6061-T6铝合金板进行单道对接焊实验,并对焊缝的力学性能和微观组织进行了分析。结果表明,用FSW方法焊接22mm厚的6061-T6铝合金板可得到成形美观、内部无缺陷的平板对接接头。在旋转速度为1000r/min、焊接速度为120mm/min时,其焊接接头的σb=205MPa,为母材强度的66%。     

机床用铝合金/不锈钢的异质搅拌摩擦焊工艺

采用不同工艺参数下的搅拌摩擦焊对接焊方法,进行了机床用6063铝合金/304L不锈钢的异质焊接试验,并进行了接头的X光无损检测以及显微组织和力学性能测试。结果表明,搅拌头旋转速度500~650 r/min、焊接速度155~185 mm/min时可获得良好的焊接接头;接头抗拉强度可达139 MPa,达到6063铝合金母材抗拉强度的67%,达到304L不锈钢母材抗拉强度的17%。搅拌头旋转速度优选550 r/min、焊接速度优选180 mm/min。     

基于田口法的高硅铝合金超高旋转速度搅拌摩擦焊接工艺优化

超高旋转速度搅拌摩擦焊借助超高旋转速度摩擦热量实现了薄板高硅铝合金的连接,这一方法大大降低了搅拌摩擦焊接的轴向力,减小了焊接变形,对焊接薄板铝合金具有独特的优势。文中以焊缝成形质量和焊接接头抗拉强度作为响应值,基于田口法对影响焊接质量的主要焊接工艺参数(旋转速度、焊接速度和下压量)进行试验设计,优化高硅铝合金超高旋转速度搅拌摩擦焊工艺。结果表明,焊接速度和下压量是显著影响因素,最优焊接工艺参数焊接速度为60 cm/min,旋转速度为14 000 r/min,下压量为1.8 mm。这一工艺条件下高硅铝合金超高旋转速度搅拌摩擦焊接接头的最大抗拉强度为129 MPa,达到母材高硅铝合金抗拉强度的97%。     

2A12铝合金搅拌摩擦焊接过程中接头组织与焊接工艺的关系

利用搅拌摩擦焊接方法对2A12铝合金板材进行了焊接试验，探讨了搅拌头的设计参数、焊接过程的工艺参数等对2A12铝合金板材焊接接头组织的影响。经过试验得知，在焊接时，搅拌头转速可为750r／min～1180r／min，走动速度为23．5mm／min～30mm／min，皆可获得接头性能尚可的焊接接头。同时发现焊接区的硬度约为母材硬度的70％。搅拌头长度略小于焊接板材厚度时仍可能使板材焊透。采用带有螺纹的搅拌头进行焊接对焊缝孔洞的形成有一定影响。     

基于田口法的高硅铝合金超高旋转速度搅拌摩擦焊接工艺优化

超高旋转速度搅拌摩擦焊借助超高旋转速度摩擦热量实现了薄板高硅铝合金的连接,这一方法大大降低了搅拌摩擦焊接的轴向力,减小了焊接变形,对焊接薄板铝合金具有独特的优势。文中以焊缝成形质量和焊接接头抗拉强度作为响应值,基于田口法对影响焊接质量的主要焊接工艺参数(旋转速度、焊接速度和下压量)进行试验设计,优化高硅铝合金超高旋转速度搅拌摩擦焊工艺。结果表明,焊接速度和下压量是显著影响因素,最优焊接工艺参数焊接速度为60 cm/min,旋转速度为14 000 r/min,下压量为1.8 mm。这一工艺条件下高硅铝合金超高旋转速度搅拌摩擦焊接接头的最大抗拉强度为129 MPa,达到母材高硅铝合金抗拉强度的97%。     

12mm厚6082铝合金搅拌摩擦焊工艺

针对12 mm厚6082-T6铝合金厚板进行了搅拌摩擦焊试验,分析了搅拌头旋转速度对接头表面成形的影响,测试了接头的力学性能。研究表明,焊接速度保持150 mm/min时,工艺窗口较宽。搅拌头旋转速度在350~450 r/min之间变化时,焊缝成形美观,但随着搅拌头转速的进一步提升,焊缝表面粗糙度有所增加。拉伸测试结果表明,搅拌头转速450 r/min时,焊接接头强度最高为225.25 MPa,达母材强度的75%。弯曲测试结果显示,在不同搅拌头转速下形成的接头均表现出优良的弯曲性能。     

汽车用5754铝合金板材搅拌摩擦焊工艺研究

对3 mm厚汽车用5754铝合金板材的搅拌摩擦焊(FSW)工艺进行系统研究,研究了焊接速度、轴肩直径和搅拌针长度等工艺参数对搅拌摩擦焊接头(对接和搭接)微观组织和力学性能的影响。结果表明,随着焊接速度的提高, 5754铝合金FSW对接接头的焊核区和轴肩区的面积逐渐减小,而搅拌针区面积先增大后减小。当焊接速度为300 mm/min时, 5754铝合金FSW对接接头的强度系数达到0.975,这是因为轴肩区和搅拌针区面积相近(面积比例为0.97),增大了焊核区和热影响区界面面积。随着5754铝合金FSW搭接搅拌针长度的增加,上下板材接触面积逐渐增大,最大拉力和抗剪强度呈先降低而后提高的趋势。研究结果表明,当上板为前进侧焊接时,焊缝中产生严重隧道缺陷,最大拉力显著减小;轴肩直径由10 mm增加到12 mm时,搭接接头中轴肩区和搅拌针区的面积相近,此时微观组织中没有隧道缺陷,接头的最大拉力和抗剪强度较高。     

铜与铝异质搅拌摩擦焊的工艺研究

采用不同的工艺参数对3 mm厚的T2纯铜板材与5383铝合金板材进行了对接搅拌摩擦焊试验,并对焊接接头的显微组织、拉伸性能和耐腐蚀性能进行了测试与对比分析。结果表明,选择适当的工艺参数,可以实现T2纯铜板材与5383铝合金板材的对接搅拌摩擦焊,搅拌头旋转速度、焊接速度和轴肩压力都会影响接头的拉伸性能和耐腐蚀性能,其优选的工艺参数为:搅拌头旋转速度ω=950 r/min、焊接速度v=140 mm/min、ω/v=6.79、轴肩压力P=8 kN。     

Friction Stir Knead Welding of steel aluminium butt joints

To develop steel aluminium-tailored hybrids in a butt joint for sheets in a thickness of about 1 mm conventional Friction Stir Welding is not feasible due to a high distortion of the welded specimen. Contrary to Friction Stir Welding the tool used for Friction Stir Knead Welding has no pin wherefore higher welding speeds can be realised. Due to the fact that this is a newer process, applied for patent in 2005, the cut contours of the edges and their variations have to be optimised by numerical analysis to transfer a maximum of load in order to improve the formability. The examined materials in this paper are steel DC04, as well as the aluminium alloys AA5182 and AA6016 in sheet thicknesses of 1 mm. Accompanying experimental investigations, as tensile tests, will evaluate the quality of the welding mechanism. As the mechanics of the new welding technology is not fundamentally investigated until now, metallographic investigations are performed, and additionally micro hardness measurements are carried out to verify the changes in the hardness distribution in the welding zone after stirring and welding.     

Influences of process parameters on tensile strength of friction stir welded cast A319 aluminium alloy joints

Fusion welding of cast A319 (Al-Si-Cu) alloy will lead to many problems including porosity, micro-fissuring, and hot cracking. Friction Stir Welding (FSW) can be used to weld A319 alloy without these defects. In this investigation, an attempt has been made to study the effect of FSW process parameters on the tensile strength of A319 alloy welded joints. Joints were made using different combinations of tool rotation speed, welding speed, and axial force, each at four levels. The quality of weld zone was analyzed using macrostructure and microstructure analysis. Tensile strength of the joints were evaluated and correlated with the weld zone microstructure. The joint fabricated with a 1200 rpm tool rotation speed, 40 mm/min welding speed, and 4 kN axial force showed superior tensile strength compared with the other joints.     

The effect of material arrangement on mechanical properties in Friction Stir Welded dissimilar A5052/A5J32 aluminum alloys

The joining of dissimilar A5052 and A5J32 alloy sheets with thicknesses of 1.5mm and 1.6mm, respectively, was carried out using the Friction Stir Welding (FSW) technique. The tool rotated at a speed in a range of 1000 rpm to 1500 rpm with a welding speed ranging from 100 mm/min to 400 mm/min. The hardness and tensile properties of the friction stir welded A5052/A5J32 joint were investigated according to the fixing location. In the case where the A5J32 aluminum alloy was fixed on the retreating side, defect-free welds were obtained under all welding conditions. However, in the case where the A5052 aluminum alloy was fixed on the retreating side, some welding defects were observed at the joint under certain welding conditions with a lower heat input. However, the welding defects had no effect on the mechanical properties. A good correlation between the hardness distribution and the welding zones was observed. The experimental results showed that the tensile properties differed depending on the fixing location of the materials and were also affected by the welding conditions.     

LY12搅拌摩擦焊焊缝成型及接头微观组织分析

利用MEF3光学显微镜和JSM-6700F场发射扫描电镜分析不同焊接参数下焊缝成型特点及无缺陷致密焊接接头的微观组织变化。研究表明:对厚6mmLY12合金,当焊接速度在20mm/min时,搅拌头旋转速度在1200～900r/min间变化时焊缝致密无缺陷,其焊核区晶粒从上表面到下表面逐渐减小;等轴晶粒出现在搅拌头尺寸范围内,在搅拌头尺寸边缘地带,突然出现具有一定流向的受拉变形的晶粒带;接近轴肩的末端区域有热量输入,晶粒开始长大。     

Mechanical Properties and Welding Power of Friction Stirred AA2024-T35 Joints

This study is concerned with the effect of friction stir welding (FSW) parameters on the mechanical properties and the consumed welding power for AA2024-T35 joints. AA2024-T35 is friction stir welded at different welding speeds (16, 40, and 80 mm/min), rotation speed (900, 1120, and 1400 rpm), and two tool profiles (triangular and square). The welding power is measured and evaluated with two previously established models (O. Frigaad, O. Grong, and O.T. Midling, A Process Model for Friction Stir Welding of Age Hardening Aluminum Alloys, Metall. Mater. Trans. A, 2001, 32A, p 1189–1200; O.P. Heurtier, M.J. Jones, C. Desrayaud, J.H. Driver, F. Montheillet, and D. Allehaux, Mechanical and Thermal Modelling of Friction Stir Welding, J. Mater. Process. Technol., 2006, 171, p 348–357). The tool profile as well as the welding speed show significant effect on the microstructure especially at lower welding speeds. The increase of the welding speed improves the mechanical properties for both tool profiles whereas it has an insignificant effect on the welding power. The square profile produces better mechanical properties and consumed more power, at 40 mm/min, than the triangular one. Moreover, the welding speed showed a weak effect on the welding power, but the need of power increased with the increase of the rotation speed. The measured power is found to be in agreement with the computed one through a theoretical work established by Heurtier et al. (Mechanical and Thermal Modelling of Friction Stir Welding, J. Mater. Process. Technol., 2006, 171, p 348–357).     

工艺参数对ECAP镁合金焊接接头性能的影响

研究了厚度为15mm的等径弯曲通道变形AZ31镁合金的搅拌摩擦焊工艺，对焊接的成形特点和力学性能进行了分析。试验结果表明：工艺参数对于焊缝成形有很大的影响，当焊接速度为37.5mm/min和搅拌头旋转速度为750r/min时，接头平均抗拉强度为母材的91%，旋入侧与旋出侧的硬度值有明显差异，接头区域的硬度值均低于母材，在热影响区域附近出现一个峰值。拉伸断口形貌表现出韧性断裂特征。     

LY12搅拌摩擦焊焊缝成型及接头微观组织分析

利用MEF3光学显微镜和JSM-6700F场发射扫描电镜分析不同焊接参数下焊缝成型特点及无缺陷致密焊接接头的微观组织变化。研究表明：对厚6mmLY12合金，当焊接速度在20mm／min时。搅拌头旋转速度在1200～900r／min间变化时焊缝致密无缺陷，其焊核区晶粒从上表面到下表面逐渐减小：等轴晶粒出现在搅拌头尺寸范围内，在搅拌头尺寸边缘地带，突然出现具有一定流向的受拉变形的晶粒带：接近轴肩的末端区域有热量输入，晶粒开始长大。     

ZK60镁合金自持式搅拌摩擦焊工艺

采用直径为16 mm且表面刻有逆时针旋转的螺旋槽的轴肩,直径为6 mm的圆柱形光面搅拌针且沿长度方向加工三个对称平台的自持式搅拌摩擦焊搅拌头,成功进行了3 mm厚ZK60镁合金薄板自持式搅拌摩擦焊,研究了焊接参数对接头表面成形、缺陷的形成及力学性能的影响。研究结果表明,搅拌头旋转速度为600r/min不变,焊接速度较低时,接头上、下表面产生沟槽缺陷,增大焊接速度获得表面无缺陷的接头,过分增加焊接速度,在前进侧和后退侧分别形成线状缺陷和孔洞缺陷,接头的力学性能随焊接速度的增大线增大后减小;采用焊接速度为400 mm/min不变,采用较低的搅拌头旋转速度时,接头表面鱼鳞纹均匀、成形美观、接头表面和内部均无缺陷,旋转速度过分增大,鱼鳞纹粗糙,在前进侧和后退侧接头内部分别产生线状缺陷和孔洞缺陷,接头力学性能随搅拌头旋转速度增大而减小。接头最大的抗拉强度为270 MPa,断后伸长率为8. 92%,接头强度系数达到87%。     

LY12铝合金摩擦点焊工艺及力学性能

摩擦点焊是在搅拌摩擦焊基础上开发的一种新型固态连接技术.针对2 mm厚的LY12铝合金,研究了摩擦点焊过程中的焊接工艺参数对焊点成形及力学性能的影响.结果表明,当焊接时间一定,搅拌头旋转速度较高时,焊点的表面成形较好;随着搅拌头旋转速度的降低,焊点的表面成形逐渐变差.焊点的抗剪载荷随搅拌头旋转速度增加呈现出先增大后减小的趋势,当搅拌头旋转速度为950 r/min、焊接时间为8 s时,焊点的抗剪载荷达到最大值,为9.33 kN/点.焊点横截面的显微硬度测试结果表明,显微硬度沿匙孔中心呈高-低-较高-低-高的"W"形分布,最小值出现在热影响区,塑性区的显微硬度较高,但略小于母材.     

7050铝合金搅拌摩擦焊接头微观组织及力学性能分析

采用搅拌摩擦焊焊接厚12 mm的7050铝合金,分析接头的微观组织和力学性能。研究结果表明,焊核区由于热循环作用形成细小的等轴再结晶组织;热机影响区受机械和热的双重作用组织发生了较大程度的变形,在热循环的作用下发生回复反应;热影响区仅受热循环的作用,组织稍微有粗化现象。力学试验表明:旋转速度400r/min、焊接速度180mm/min时,接头的抗拉强度可以达到391 MPa,为母材的77%;焊接速度200 mm/min,旋转速度450 r/min时,接头的抗拉强度可以达到376 MPa,为母材的74%。断口形貌分析显示,接头断裂模式为穿晶和沿晶混合型断裂。