钛合金搅拌摩擦焊搅拌头研究现状

搅拌摩擦焊在焊接钛合金这类高熔点金属方面具有很大优势,但是搅拌头的磨损一直是其一大难点。对钛合金搅拌摩擦焊中的搅拌头结构、材料选择进行了讨论,认为圆锥形搅拌针综合性能较好,而在材料选择方面,认为目前应用前景较好的是钨铼合金,但不同材料的组合可能更符合未来发展的方向。为了研究搅拌头的磨损机理及如何减小磨损,列举了几种辅助焊接工艺及目前应用较广的模拟仿真,指出辅助焊接工艺可减小搅拌头磨损,但目前工艺不完善等问题依然存在,需要进一步优化,包括模拟仿真在内,对于钛合金搅拌摩擦焊搅拌头结构、材料优化、磨损机理、辅助焊接工艺等研究均较少,限制了其研究进展及应用。     

镁合金搅拌摩擦焊技术的研究进展

搅拌摩擦焊技术是近十几年发展起来的,适合于低熔点合金的一种新型焊接方法。由于镁合金具有密度小、比强度高、尺寸稳定性好等特点,目前镁合金的搅拌摩擦焊已经引起了越来越多的关注。综述了国内外镁合金搅拌摩擦焊接技术的研究现状,包括镁合金与同种及异种合金的连接技术,并展望了镁合金搅拌摩擦焊技术的发展趋势。     

MB8镁合金薄板的搅拌摩擦焊

针对我国航空航天工业常用的MB8镁合金。采用搅拌摩擦焊工艺进行焊接,对其焊缝的成形特点、组织特征和力学性能进行分析。结果表明,采用搅拌摩擦焊焊接镁合金效果良好。     

铝基复合材料搅拌摩擦焊搅拌头设计

文中介绍了铝基复合材料搅拌摩擦焊搅拌头材料选择和结构设计方案。根据铝基复合材料复杂的微观和宏观结构,选定钢结硬质合金GT35制造搅拌头,并与选用工具钢制作的普通搅拌头进行对比。对比结果表明,普通搅拌头焊后磨损严重,焊缝质量较差。对搅拌头形状和尺寸进行了设计：最初的“一字凹凸槽”设计存在不同心德患,给加工制造造成困难;后改为分体式搅拌头,采用螺纹连接。采用这种搅拌头能得到表面光滑,宏观形貌良好的接头。     

船用5083铝合金厚板搅拌摩擦焊接工艺研究

研究了30 mm厚铝合金5083板材双面对接焊不同焊接速度和旋转速度的焊接参数组合对焊接接头成型质量及力学性能的影响,结果表明,当焊接参数处于旋转速度为400 r/min~600 r/min,焊接速度为80mm/min~120 mm/min的工艺参数窗口内时,可以获得焊缝成型质量与抗拉性能优异的焊缝。     

搅拌摩擦焊焊缝腐蚀研究进展

搅拌摩擦焊是一项新型固态连接技术，近年来在航空航天、汽车工业等领域得到了广泛应用。其工艺特性导致各焊缝微区组织和应力状况不同，从而展现出不同的腐蚀行为。综述了近年来国内外搅拌摩擦焊焊缝腐蚀行为的研究进展，分析了影响焊缝腐蚀的因素，展望了发展趋势。     

钛合金搅拌摩擦焊研究现状

搅拌摩擦焊是目前钛合金焊接技术研究的热点.从搅拌头材料与结构设计、焊接工艺与组织性能关系、焊接过程数值仿真等方面综述了钛合金搅拌摩擦焊国内外研究现状.以现有的研究结果来看,搅拌摩擦焊是实现钛合金高强可靠连接的有效途径,选择合适的焊接参数和焊后热处理工艺可获得高质量钛合金焊接接头;但由于对钛合金用高温高强高耐磨搅拌头研制...     

搅拌摩擦焊温度场研究进展

自1991年英国焊接研究所(TWI)发明了搅拌摩擦焊(FSW)以来,许多学者对搅拌摩擦焊接过程中的温度场分布进行了大量的研究。随着人们对搅拌摩擦焊接物理机制的深入了解,描述其温度场分布的模型也越来越精确,由最初仅考虑摩擦产热,发展到综合考虑摩擦产热和材料塑性变形产热,近年来一些研究者更是尝试建立热力耦合的模型来描述其温度场分布。简要叙述了关于搅拌摩擦焊温度场研究的发展历程及研究现状。     

国内外搅拌摩擦焊用搅拌头的研究现状及发展趋势

本文概述了国内外搅拌摩擦焊用搅拌头在搅拌头材料开发、轴肩和搅拌针设计优化、搅拌头抗磨损破坏性等方面开展的工作进展。预测了搅拌头研究的未来发展趋势主要集中在低成本高性能搅拌头新材料和制造技术研发、搅拌头设计技术的改进和优化等。这将对我国搅拌摩擦焊行业的战略规划、技术研发、成果应用等工作的开展起到重要启示作用。     

镁合金搅拌摩擦焊接组织特征研究

通过对镁合金AZ31进行搅拌摩擦焊获得了成型良好的焊缝,采用金相显微镜对焊缝组织进行了分析,并采用透射电镜和X射线能谱仪对晶粒形貌和晶界析出的第二相进行了观测分析。结果表明,镁合金搅拌摩擦焊可以获得组织致密的焊缝,焊缝区域根据组织特点可以分为焊核区、热机影响区和热影响区;焊核区"洋葱环"之间呈现层片状结构,晶界强化相数量减少且尺寸变小;热机影响区在前进侧和焊核区有明显的分界,晶粒呈细长条状,后退侧和焊核区分界相对不明显,晶粒变形较小;热影响区在前进侧较窄,组织与母材组织相比变化较小,而后退侧热影响区较宽,晶粒尺寸有所增长,这与搅拌摩擦过程中金属切削迁移的堆积过程有关。     

Effect of Process Parameters on Tensile Strength of Friction Stir Welded Cast LM6 Aluminium Alloy Joints

This paper reports the effect of friction stir welding(FSW)process parameters on tensile strength of cast LM6 aluminium alloy.Joints were made by using dierent combinations of tool rotation speed,welding speed and axial force each at four levels.The quality of weld zone was investigated using macrostructure and microstructure analysis.Tensile strength of the joints were evaluated and correlated with the weld zone hardness and microstructure.The joint fabricated using a rotational speed of 900 r/min,a weldin...     

Friction stir welding of aluminium hollow extrusion: weld formation and mechanical properties

Novel friction stir welding (FSW) technique, characterised by big concave upper and small convex lower shoulders, for aluminium hollow extrusion was studied. Assisted with the lower shoulder, root flaws due to the lack of tool penetration have been eliminated. The tensile strength increased with increasing welding speed. As the welding speed increases from 50 to 200 mm min^?1, the width of the welding nugget zone (WNZ) decreases, and the ductile fractured location occurred at WNZ instead of heat affected zone (HAZ) adjacent to thermomechanically affected zone (TMAZ). The interface between the TMAZ and HAZ exhibited the lowest microhardness. The results indicated that the novel FSW method has the potential to join tubular structures and hollow profiles widely used in transportation industries.     

Force response characteristics and mechanical properties of friction stir welded AA2024 sheets

Process force and tensile properties in friction stir welding of AA2024 sheets were studied. Results show that the forces present a periodic variation with the same periodicity which is nearly equal to the time of one tool rotation, and thus it only depends on rotation speed. With increasing welding speed the forces increase gradually, while with increasing rotation speed the forces first decrease and then increase. Joints with superior strength-ductility synergy are produced at 900?rev?min^?1–300?mm?min^?1 and 1000?rev?min^?1–350?mm?min^?1. These joints experience nearly the same peak temperature and axial force. As heat input increases the failure initiates from the interface between nugget zone (NZ) and thermo-mechanically affected zone to heat-affected zone continuing to NZ.     

Relationship between base metal properties and friction stir welding process parameters

Friction stir welding (FSW) is a solid state welding process for joining aluminum alloys and has been employed in aerospace, rail, automotive and marine industries for joining aluminium, magnesium, zinc and copper alloys. In FSW, the base metal properties such as yield strength, ductility and hardness control the plastic flow of the material under the action of rotating non-consumable tool. The FSW process parameters such as tool rotational speed, welding speed, axial force, etc. play a major role in deciding the weld quality. In this investigation, an attempt has been made to establish relationship between the base material properties and FSW process parameters. FSW joints have been made using five different grades of aluminium alloys (AA1050, AA6061, AA2024, AA7039 and AA7075) using different combinations of process parameters. Macrostructural analysis has been done to check the weld quality (defective or defect free). Empirical relationships have been established between base metal properties and tool rotational speed and welding speed, respectively. The developed empirical relationships can be effectively used to predict the FSW process parameters to fabricate defect free welds.     

高转速FSW工艺特征及焊缝组织性能演变规律研究

目的研究不同转速的焊缝性能变化对组织的影响,以期为高转速搅拌摩擦焊工艺参数的优化和更大范围的应用提供指导。方法在3000~8000 r/min的高转速范围内对3A21-O态铝合金进行搅拌摩擦焊试验,焊后分析了焊缝成形特征和晶粒形态并测试了接头截面显微硬度。结果当转速由1000~4000 r/min区间升高至5000~8000 r/min区间时,焊核宽度急剧增大了近50%。这是由于焊具产热机制以滑移摩擦为主向以粘着摩擦为主转变,导致上述焊核宽度增大的行为。随着转速的增大,焊缝温度呈现出常规搅拌摩擦焊工艺中鲜见的先增大而后趋于稳定的变化趋势;温度随转速的这一演变特征导致焊缝焊核区的亚结构数量比例以及显微硬度都随转速呈现出与此相近的演变规律。结论在高转速搅拌摩擦焊中,转速提高能提高焊缝性能,且增强的焊缝性能能够在较宽的高转速区间内保持相对稳定的状态。