搅拌摩擦点焊

搅拌摩擦点焊(FSSw)是一种最近研究开发出来的新焊接技术.同目前的电阻点焊相比,该方法是具有节能、设备简单、焊点强度高、变形小、焊前表面清理简单,可以焊接厚度差别大的材料,特别适用于高强度铝合金的焊接.重点介绍该技术的基本原理、优缺点、焊接设备,对几种典型铝合金的焊接工艺参数、接头强度和组织等进行了比较详细的分析,从而对该技术有一个全面的了解.     

Friction stir welding of aircraft wings

ABSTRACT

To reduce the weight of the wings of the TU-204SM aircraft, investigations were carried out to design the upper wing panel made of the V-1469 high-strength aluminium–lithium alloy of the third generation. The technology of friction stir welding was developed and fragments of the welded panel produced. The tests of the stability under compression showed that the application of the welded panels reduces the weight of the wing by up to ~10% and increases the stability and load carrying capacity by up to ~30%.     

铝合金船舶的摩擦搅拌焊接工艺

摩擦搅拌焊(FSW)是在低于工件材料熔点情况下操作的固相焊接,是在旋转情况下通过一种耐磨工具将板材或型材材料连接的工艺,可用于铝、镁、铜等的焊接,焊接质量优良.通常情况下,摩擦搅拌焊的焊缝强度超过热影响区.介绍了摩擦搅拌焊在造船和船舶制造业上的应用,以及船舶工业的研究需求.     

铝合金的搅拌摩擦焊

在详细介绍搅拌摩擦焊原理，特点的基础上，针对铝合金的搅拌摩擦焊特点，性能以及工业应用进行了阐述，并且对搅拌摩擦焊在中国市场的发展和应用作了简略介绍和预测。     

Friction stir welding of copper alloys

Copper plates ,brass plates and copper/brass plates were friction stir welded with various parameters. Experimental results show that the microstructure of the weld is characterized by its much finer grains as contrasted with the coarse grains of parent materials and the heat-affected zones are very narrow. The microhardness of the copper weld is a little higher than that of parent plate. The microhardness of brass weld is about 25% higher than that of parent material. The tensile strength of copper joints increases with increasing welding speed in the test range. The range of parameters to obtain good welds for copper is much wider than that for brass. When different materials were welded, the position of copper plate before welding affected the quality of FSW joints. If the copperplate was put on the advancing side of weld, the good quality of weld could be got under proper parameters.     

铝合金船舶的搅拌摩擦焊接工艺

0 引言 由英国焊接研究所(TWI)发明的搅拌摩擦焊(Friction Stir Welding简称FSW),是用一种利用耐磨的旋转工具将铝、镁和铜的板材或型材材料连接的工艺.     

塑料板材搅拌摩擦焊工艺

以6mm和8mm聚氯乙稀板材为研究对象,用搅拌摩擦焊方法进行了工艺可焊性试验。试验证明,一定厚度的塑料板,不开坡口,用搅拌摩擦焊方法可一次焊成。虽然影响接头质量的因素很多,但只要焊接参数选择恰当,就能获得令人满意的焊接接头。     

Friction stir welding of multilayered steel

Abstract

This study investigates the mechanical properties and microstructure of friction stir butt welded high strength/ductility multilayered steel consisting of 15 alternating layers of SUS 301 austenitic stainless steel (eight layers) and SUS 420J2 martensitic stainless steel (seven layers) with a total thickness of 1·2 mm. With optimised welding parameters, defect free welds with an ultimate tensile strength (UTS) of 1240 MPa and a fracture elongation of 13% were accomplished. This corresponds to a joint efficiency of 90%. In this case, fracture occurred in the heat affected zone as a result of a very pronounced hardness drop in the martensitic layers resulting from the formation of a large amount of grain boundary precipitates, which were formed at temperatures ～750°C slightly below A_c1. By applying post-weld heat treatment, the hardness drop in the martensitic layers was removed and the tensile properties were enhanced to UTS of 1310 MPa (95% joint efficiency) and a fracture elongation of 22%.     

Friction stir weld nugget temperature asymmetry

Abstract

Two different hardness distributions were observed to result from the friction stir welding of an Al–Mg–Si alloy using identical welding speeds but different heat inputs. In one case, the distribution was relatively symmetric about the weld centreline and in the other, the hardness declined continuously from the advancing to the retreating sides of the weld nugget. Based on in-probe temperature measurements, full-field grain size mapping, and response to post-weld heat treatment, it has been ascertained that under low heat input conditions, the weld nugget attained a higher temperature on the advancing side than on the retreating side. Such a temperature asymmetry has often been proposed and has been predicted by simulation but, has not been convincingly demonstrated before this time.     

Process forces during friction stir channeling in an aluminum alloy

An understanding of the material flow behavior during friction stir channeling (FSC) is essential to produce consistently stable and continuous channels in monolithic plates. In this study, channels were fabricated in Al6061-T6 alloy using FSC and the process forces were measured using a high frequency data acquisition system. Polar plots of the net resultant force acting on the tools are plotted and correlated with the process parameters and channel features. The magnitude and direction of the net forces acting on the tool are analyzed to understand the material flow behavior and the occurrence of channels in the nugget.     

Friction stir welding of duplex stainless steels

Duplex stainless steels are successful in a variety of applications such as the food industry, petrochemicals and plants for desalination of seawater, where high corrosion resistance and high mechanical strength are required. However, the beneficial microstructure may change during fusion welding steps, and it can compromise the performance of these materials. Friction stir welding is a solid-state process avoiding typical problems concerning solidification such as solidification cracks, liquation and segregation of alloying elements. Superduplex stainless steels can avoid unbalanced proportions of ferrite and austenite, formation of secondary deleterious phases and grain growth of ferrite in the heat-affected zone. Consolidated friction stir welded joints with full penetration 6 mm thick were obtained for UNS S32101 and S32205 duplex and S32750 and S32760 superduplex stainless steels. The friction stir welds were submitted to tensile tests indicating an improvement of strength in welded joints, showing increased yield and tensile strength for all studied cases. Regarding the microstructural characterization, an outstanding grain refinement was observed in the welded joint, achieving grain sizes as small as 1 μm. This refinement was associated with the combination of microstructural restoration mechanisms in the dual-phase microstructure promoted by severe deformation associated with a high temperature during the welding process.     

Friction stir welding of DH36 steel

Abstract

Hot rolled DH36 carbon steel, 6.4 mm in thickness, was friction stir welded at speeds of 3.4 mm s^-1 (8 in min^-1), 5.1 mm s^-1 (12 in min^-1), and 7.6 mm s^-1 (18 in min^-1). Single pass welds free of volumetric defects were produced at each speed. The relationships between welding parameters and weld properties are discussed. Optical microscopy, microhardness testing, and transverse and longitudinal tensile tests have been performed. Bainite and martensite are found in the nugget region of the friction stir welds whereas the base material is comprised of ferrite and pearlite. The maximum hardness is observed in the weld nugget, and the hardness decreases gradually from the weld nugget, through the heat affected zone, to the base metal. Tensile testing also indicates overmatching of the weld metal relative to the base metal. Maximum hardness and longitudinal (all weld metal) tensile strengths increase with increasing welding speeds. Weld transverse tensile strengths are governed by the base metal properties, as all transverse tensile bars fail in the base metal.     

Friction stir welding of aluminium casting alloys

The results of testing friction stir welding quality in relation to EN AC-43200 (AK9) and EN AC-45000 (AK64) aluminium casting alloys are presented. The test joints were made with the use of a welding machine constructed on the basis of numerically controlled milling machines. The assessment of the joint quality was made based on visual inspection, mechanical testing, weldment structure analysis and hardness tests. The purpose of the investigation was to discover the possibility of friction stir welding of casting alloys and the influence of welding conditions on joint properties and structure. The test results show good weldability of aluminium casting alloys by the FSW method. Sound welds can be obtained in a relatively wide range of welding parameters while the weld strength is satisfactory. In order to obtain the highest quality joints, the workpieces must be pressed onto the other, while the welding process cannot run with excessively high speed. The best mechanical properties of the joints were achieved when the friction process was conducted at a rotational speed of the mixing tool of 900 rpm.     

紫铜厚板的搅拌摩擦焊接

采用搅拌摩擦焊接方法对厚度为25mm的T2紫铜厚板进行了单道对接焊试验,并对焊缝的微观组织、力学性能、导电特性及焊缝能谱进行了分析.结果表明,用搅拌摩擦焊方法焊接25mm厚的T2紫铜板,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960r/min、焊接速度为70mm/min时,搅拌摩擦焊的焊接接头的抗拉强度可达到186.6MPa,搅拌摩擦焊接头的电阻率与母材基本相当.     

防锈铝搅拌摩擦焊接

通过大量试验研究了防锈铝LF21搅拌摩擦焊接技术,深入分析了防锈铝搅拌摩擦焊接头的金相组织和力学性能,并探讨了焊接参数对组织性能的影响.对于3mm厚的防锈铝板,优化的搅拌头材料为ICr18Ni9Ti,形状为圆锥带凹面形,轴肩尺寸为φ12mm,焊针跟部直径为4mm,焊针端部直径为2.8mm,焊针高度为2.7mm.优化的焊接工艺参数范围为旋转速度950-1 500 r/min,焊接速度37.5～60mm/min.研究的成果可应用于有色金属材料搅拌摩擦焊接参数的优化,推动中国搅拌摩擦焊接技术在铝焊接中的应用.     

Friction stir welding between extrusions and laminates

Current market demands drive companies to innovate their production techniques to improve products and simultaneously hold down costs. In the search for solutions aimed at an optimization of production processes, semi-finished products in aluminium alloys very definitely play a significant role. Moreover, the assembly of extruded parts with laminates may result in considerable difficulties, especially in relation to distortions or generated residual stress and process productivity. A solution to these issues may be found in the application of friction stir welding (FSW), characterized by low thermal input and high productivity. The asymmetry of the FSW process determines a different thermal input to the edges of the pieces to be joined. This aspect can be exploited when it is necessary to join pieces characterized by a very different thermal lag, as occurs in the case of joining extruded products and sheeting. This study aims to identify optimal FW parameters, placing particular attention on heat transferred to materials so as to provide an adequate thermal input that will allow for compensation of the different thermal capacity of the pieces in question.