同种材质摩擦焊接头焊缝的组织及性能研究

利用C150、C50连续驱动摩擦焊机分别对08F钢、20钢进行同种材料焊接试验.08F钢试验工艺参数为:主轴转速2000 r/min、摩擦压力9.5kN、顶锻力23.6kN;20钢试验工艺参数为:主轴转速2500 r/min、摩擦压力22kN、顶锻力30kN.焊后对其接头的组织性能进行研究.结果表明:应用连续驱动摩擦焊,能形成良好的焊接接头,接头的晶粒比母材区晶粒细小;焊接接头由塑性变形区、热影响区组成;焊接接头的硬度值大于母材区,08F钢接头的硬度值较母材区提高了约20％,20钢提高了约40％.     

铁素体不锈钢搅拌摩擦焊工艺及缺陷形成机理

采用钨铼合金搅拌工具对T4003铁素体不锈钢进行搅拌摩擦焊接工艺试验,研究搅拌摩擦焊缝成形、接头组织特征及缺陷形成机理.结果表明,不同旋转速度下随焊接速度增加,轴向压力呈单调增加趋势;当转速为150,250 r/min时,可获得无缺陷致密焊缝;当转速为350 r/min时,靠近前进侧的焊缝区出现孔洞缺陷,随着焊接速度和轴向压力不断增加,焊接缺陷有减少趋势.焊接接头焊核区发生了相变和明显淬硬现象,组织为细小等轴铁素体和低碳马氏体,焊缝具有明显不均匀硬度分布.提出了一种焊缝热塑性金属平衡流动模型分析其缺陷形成机理.     

2219铝合金薄板拉拔式摩擦塞焊工艺及力学性能优化

针对5.5 mm厚2219铝合金拉拔式摩擦塞补焊工艺及接头力学性能进行了研究。设计了4种不同几何形状的塞棒,通过试验确定了优化的塞棒几何形状和尺寸:塞棒为圆弧形(R=50 mm)、小端直径32 mm、圆锥段长度16.17 mm。在焊接转速7 000 r/min、轴向拉力30 kN、轴向进给量10 mm的工艺参数下获得了成形良好的接头。显微组织分析表明,塞棒与母材界面结合良好,毗邻结合界面的母材侧晶粒发生了动态再结晶,热机械影响区晶粒沿着塞棒的挤压方向被拉长。正交试验及分析结果表明,在焊接转速、轴向拉力和轴向进给量3个主要焊接参数中,焊接转速对接头强度的影响最大,轴向拉力次之,轴向进给量最小。当焊接转速达到7 000 r/min以上时,提高焊接轴拉力有助于提高焊接接头的抗拉强度。文中所获得焊接接头的最优抗拉强度为357 MPa,相当于母材抗拉强度的76.7%。在界面结合质量良好的情况下,塞补焊接头拉伸断裂位置为热机械影响区,断口表面呈韧性特征。     

工艺参数对X100摩擦焊接头性能影响的显著性研究

为优化X100管线钢摩擦焊焊接工艺参数,以摩擦焊焊接接头的拉伸强度和硬度为考核指标,通过正交试验,研究转速、摩擦压力、顶锻压力、缩短量等工艺参数对焊接接头性能的影响,获得了优质焊接接头工艺参数。各工艺参数对X100摩擦焊焊接接头性能影响的显著性依次为摩擦压力、转速、顶锻压力和缩短量。以焊接接头强度和硬度作为指标,获得最优工艺参数为:转速1 000 r/min、摩擦压力170 MPa、顶锻压力255 MPa、缩短量7 mm;对最优焊接工艺参数进行验证试验,所得拉伸性能参数均超过了优化前,验证了试验结果与极差分析结果的一致性。     

摩擦叠焊单元成型质量影响因素研究

摩擦叠焊单元成型的工艺参数对接头表面成形及其性能有着决定性的影响.进行了大量焊接工艺试验,考查了各种参数组合下的焊接接头质量,对比各焊接参数下接头的微观组织、宏观形貌和焊接压力,分析缺陷出现的原因并提出改善方法.结果表明:主轴转速在3500r/min以上,焊接速度40mm/min以上的范围内,得到的焊接接头组织致密均匀...     

大轴向力低转速2219铝合金拉塞焊工艺探究及接头性能分析

拉锻式摩擦塞补焊（FPPW）是对火箭燃料贮箱制造缺陷进行高质量修补的重要手段。使用圆柱形塞孔、圆弧形塞棒以及成型垫板，开展大轴向力、低转速条件下6 mm厚2219-T87铝合金的拉锻式摩擦塞补焊工艺试验，并对焊缝成形和接头力学性能进行研究。在给定参数区间中，正交实验设计法推测出较优的工艺参数组合是：焊接转速4 000 r/min、焊接轴向力60 kN以及焊接进给量6 mm。对由优化参数组合获得的焊接接头，光学显微镜、X光探伤显示接头无缺陷，热影响区极小；拉伸试验结果表明接头抗拉强度达372 MPa，屈服强度达242 MPa，断后伸长率为4.5%。     

轴向压力对异种钢水下摩擦锥塞焊接头组织及力学性能的影响

在X52管线钢上采用Q345塞棒进行水下摩擦锥塞焊工艺试验研究，讨论轴向压力对塞焊接头组织和力学性能的影响. 结果表明，对给定7 000 r/min焊接转速在30 kN轴向压力下，塞焊缝底部圆角过渡处易产生未结合缺陷，随着轴向压力增加达到35 kN以上，可以获得完全结合的致密塞焊缝，焊缝顶锻区及底部圆角过渡处的热影响区也不断扩大. 由于水介质快速冷却作用，焊缝区组织特征比较复杂，主要由板条状马氏体和板条状贝氏体组成，硬度分布不均匀并产生明显淬硬现象其硬度可达450 HV1. 在0 ℃下焊缝中心冲击吸收能量也会随着轴向压力的增加而不断提高，最高可以达到62 J，但远低于母材的267 J.     

5A06铝合金搅拌摩擦焊焊接工艺参数对焊缝成形性影响

研究了搅拌摩擦焊工艺参数对8 mm厚的5A06-O铝合金焊缝成形的影响。结果表明:选择合适的焊接工艺参数才能得到合格的焊缝,焊接参数为焊接压力f=40 kN,搅拌头转速ω=450 r/min,焊接速度v=28 cm/min和f=35 kN,ω=300 r/min,v=20 cm/min时,焊缝成形均较好,外部和内部均无缺陷。工艺参数选择不合适时,焊缝成形较差,易形成各种类型的缺陷。对于不同类型的缺陷,需要适当地调整不同的工艺参数来达到消除缺陷的目的。     

7022铝合金搅拌摩擦焊工艺参数的优化

根据经验并通过试验拟定出10mm厚7022铝合金FSW的工艺参数范围为:搅拌头转速(ω) 300～600r/min,焊接速度(v)30～100 mm/min,并对各参数下的焊接试样进行拉伸试验、显微硬度测试和冲击试验.试验结果显示,焊接接头的抗拉强度和屈服强度范围分别为505～615 MPa和464～532 MPa;焊接接头的最大硬度出现在焊缝区中间部位,最小硬度出现在热影响区;焊接接头的冲击韧性仅在ω=300 r/min、v=30和50 mm/min时略低于母材,其余工艺参数下焊接的试样均高于母材.试验获得的最佳焊接工艺参数为:ω=400 r/min、v=100 mm/min.     

协同双面搅拌摩擦焊接6061铝合金工艺

针对常规顺序双面搅拌摩擦焊接（DS-FSW）的变形大、耗时长等问题，提出了一种协同双面搅拌摩擦焊接（SDS-FSW）技术，并通过研制的设备研究了SDS-FSW 6061铝合金接头的微观组织和力学性能。结果表明，当主轴转速为1 800 r/min，焊接速度为1 200 mm/min时，SDS-FSW焊接接头缺陷较相同焊接参数下DS-FSW接头的有所改善；在该焊接参数下，SDS-FSW接头的变形量（0.15 mm）远小于DS-FSW接头的变形量（1 mm），且接头的拉伸性能更好，SDS-FSW和DS-FSW接头的最大拉力分别为36.8 kN和34.9 kN。     

Multi-objective optimization of friction stir welding parameters using desirability approach to join Al/SiCp metal matrix composites

Silicon carbide particulate (SiC_p) reinforced cast aluminium (Al) based metal matrix composites (MMCs) have gained wide acceptance in the fabrication of light weight structures requiring high specific strength, high temperature capability and good wear resistance. Friction stir welding (FSW) process parameters play major role in deciding the performance of welded joints. The ultimate tensile strength, notch tensile strength and weld nugget hardness of friction stir butt welded joints of cast Al/SiC_p MMCs (AA6061 with 20% (volume fraction) of SiC_p) were investigated. The relationships between the FSW process parameters (rotational speed, welding speed and axial force) and the responses (ultimate tensile strength, notch tensile strength and weld nugget hardness) were established. The optimal welding parameters to maximize the mechanical properties were identified by using desirability approach. From this investigation, it is found that the joints fabricated with the tool rotational speed of 1370 r/min, welding speed of 88.9 mm/min, and axial force of 9.6 kN yield the maximum ultimate tensile strength, notch tensile strength and hardness of 265 MPa, 201 MPa and HV114, respectively.     

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.     

Improving the Weld Formation and Mechanical Properties of the AA-5A06 Friction Pull Plug Welds by Axial Force Control

In the present study, the weld formation and mechanical properties of the AA-5A06 friction pull plug welded(FPPW) joints were improved by controlling the axial force history. Several defect-free FPPW joints were made successfully by using the welding parameters of 15–20 k N/s axial loading rate, 20–30 k N axial welding force and 6–7 mm axial feeding displacement. The results indicated that using higher axial loading rate and axial welding force produced more stable heat generation and shorter frictional heating time between the frictional interface. In this case, the plastic flow of the materials around the hole could be further improved since the axial feeding displacement of the plug was increased. The maximum ultimate tensile strength(UTS) and elongation of the FPPW 5A06 joints were 314 MPa and 4.8%, respectively. The thermal mechanically affect zone(TMAZ) had the lowest hardness value throughout the joint and was found as the fracture location to all the tensile samples. The softening of TMAZ was mainly caused by the weakening of the cold work hardening and the coarsening of grains.     

Mechanical properties of friction stir welded Al alloys with different hardening mechanisms

The mechanical properties of precipitation hardened Al 6061-T651 and Al 7075-T6 and strain hardened Al 5083-H32, friction stir welded with various welding parameters, were examined in the present study. 4 mm thick Al 6061-T651, Al 7075-T6, and Al 5083-H32 alloy plates were used for friction stir welding (FSW) with rotating speed varied from 1000 to 2500 rpm (rotation per minute) and welding speed ranging from 0.1 to 0.4 mpm (m/min). Each alloy displayed slightly different trends with respect to the effect of different welding parameters on the tensile properties of the FSWed Al alloys. The tensile elongation of FSWed Al 6061-T651 and Al 7075-T6 tended to increase greatly, while the tensile strength decreased marginally, with increasing welding speed and/or decreasing rotating speed. The tensile strength and the tensile elongation of Al 6061-T651 decreased from 135 to 154 MPa and 10.6 to 17.0%, respectively, with increasing welding speed from 0.1 to 0.4 mpm at a rotating speed of 1,600 rpm. Unlike the age-hardened Al 6061-T651 and Al 7075-T6, the strain-hardened Al 5083-H32 showed no notable change in tensile property with varying welding parameters. The change in the strength level with different welding parameters for each alloy was not as significant as the variation in tensile elongation. It was believed that the tensile elongation of FSWed Al alloys with varying welding parameters was mainly determined by the coarse particle clustering. With respect to the change in tensile strength during friction stir welding, it is hypothesized that two competing mechanisms, recovery by friction and heat and strain hardening by plastic flow in the weld zone offset the effects of different welding parameters on the tensile strength level of FSWed Al alloys.     

铝合金搅拌摩擦焊缝摩擦塞补焊组织与力学性能

对2219-T87铝合金搅拌摩擦焊缝进行摩擦塞补焊工艺试验,对塞补焊接头的焊缝成形、显微组织、显微硬度和抗拉强度进行了观察和测试,对拉伸断口进行了扫描电镜观察.结果表明,在7 500 r/min的焊接转速和40~55 kN的焊接压力下可获得无缺陷摩擦塞补焊接头;塞补焊接头沿垂直于搅拌焊缝方向的最大抗拉强度和断后伸长率分别可以达到336 MPa和8%,分别相当于母材抗拉强度和断后伸长率的73.9%和66.7%;在母材和塞棒之间的底部结合面是最薄弱的区域,如何控制该区域的结合强度是影响摩擦塞补焊接头拉伸性能的关键因素.     

搅拌摩擦焊工艺参数对铸态A356铝合金抗拉强度的影响(英文)

A356是一种高强度铝硅铸造态合金,广泛用于食品、化工、船舶、电器和汽车行业。熔焊这种铸造合金时存在许多问题,如孔隙、微裂隙、热裂等。然而,用搅拌摩擦焊(FSW)来焊接这种铸造态合金可以避免上述缺陷发生。研究了搅拌摩擦焊工艺参数对铸造态A356铝合金抗拉强度的影响;对旋转速度、焊接速度和轴向力等工艺参数进行优化;从宏观和微观组织分析角度对焊接区的质量进行分析;对焊接接头的抗拉强度进行了测定,并对抗拉强度与焊缝区硬度和显微组织的相关性进行了研究。在旋转速度1000r/min、焊接速度75mm/min和轴向力5kN的条件下得到的焊接接头具有最高的抗拉强度。     

30 mm 7A05铝合金搅拌摩擦焊接头组织及力学性能

采用搅拌摩擦焊方法利用新型搅拌头对30 mm厚的7A05-T6铝合金进行了单道对接,焊后分析讨论了焊缝接头微观组织和力学性能.结果表明,接头焊核区发生动态再结晶,生成细小的等轴晶粒;焊缝两侧热力影响区受机械和热的双重作用,组织存在较大差异,前进侧为窄条状组织,后退侧为扁平状组织;热影响区晶粒粗化;在焊接30 mm板时,工艺参数范围较窄,旋转频率为360 r/min,焊接速度为100 mm/min时,可获得无缺陷、成形好的焊缝;接头抗拉强度为367.7 MPa、屈服强度为280.8 MPa、断后伸长率为14.4%高于母材,接头抗拉强度可达母材的95%.接头显微硬度的分布呈类似W形分布,热影响区软化趋势比较明显.     

Characteristics of Nd： YAG laser welded 600 MPa grade TRIP steel

Microstructures and mechanical properties of Nd: YAG laser welded transformation induced plasticity (TRIP) steel with tensile strength of 645 MPa were studied. Due to high cooling speed of laser welding, the weld metal mainly consists of martensite different from the base metal, which is composed of ferrite matrix with bainite and a little retained austenite. Therefore, the weld metal has maximum hardness at welded joint. The yield strength and tensile strength of welded specimens tested perpendicular to weld line were almost equal to those of the base metal. But the yield strength and tensile strength of welded specimens tested parallel with weld line were a little higher than those of the base metal. The formability of laser welded TRIP steel was decreased compared with that of the base metal.     

耐磨铝硅铜合金的双面搅拌摩擦焊

对10 mm厚的铝硅铜合金进行了双面搅拌摩擦焊接,研究了焊接接头的显微组织及力学性能.研究表明,铸态金属晶粒和硅粒子在双面搅拌摩擦焊接过程中得到细化,硅颗粒分布均匀化.反面焊道比正面焊道的晶粒细化和硅粒子均匀化作用更明显.异向焊接的接头强度较低,所有接头均断在焊缝的前进侧.同向焊接的接头强度较高,接头断裂位置取决于焊接参数.选用搅拌头旋转频率为950 r/min、焊接速度为10mm/min的参数焊接时,同向接头表面成形好、内部无缺陷,其强度可达母材的87.4%.