The effect of tool geometry on welding joint quality for aluminum 1100

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Friction stir welding (Fsw) uses anon consumable tool to generate friction heat in the abutting surface, the welding parameter such as rotational speed, welding speed, tool tilt angle and tool pin profile play a major role to produce best quality joint.

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Nội dung Text: The effect of tool geometry on welding joint quality for aluminum 1100

International Journal of Mechanical Engineering and Technology (IJMET) Volume 10, Issue 03, March 2019, pp. 1982-1993, Article ID: IJMET_10_03_200 Available online at http://www.iaeme.com/ijmet/issues.asp?JType=IJMET&VType=10&IType=3 ISSN Print: 0976-6340 and ISSN Online: 0976-6359 © IAEME Publication Scopus Indexed THE EFFECT OF TOOL GEOMETRY ON WELDING JOINT QUALITY FOR ALUMINUM 1100 Noori Hasson Mohammed Al- Saadi* Assistant Professor, Research Filed: Applied Mechanics, Civil Engineering Department, Dijlah University College, Baghdad, Iraq ABSTRACT Friction stir welding (Fsw) uses anon consumable tool to generate friction heat in the abutting surface, the welding parameter such as rotational speed, welding speed, tool tilt angle and tool pin profile play a major role to produce best quality joint. in this project we select two tool geometries square and triangle and constant tilt angle 2° as well as to three rotational speed 800,1000,1200 rpm and constant welding speed 35mm/min.under the above parameters we peformed six specimens at different condition and two kinds of tool geometring (square,triangle) After the tensile test for all specimens it is clear to detect that the Square tool under 1200 rpm and welding speed 30mm/min produce the high tensile stress due to heat generation at this condition. Key words: Friction stir welding (Fsw), tool geometries Cite this Article: Noori Hasson Mohammed Al- Saadi, The Effect of Tool Geometry on Welding Joint Quality for Aluminum 1100, International Journal of Mechanical Engineering and Technology 10(3), 2019, pp. 1982–1993. http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=10&IType=3 1. INTRODUCTION 1.1 General Introduction Welding is a material joining process for a permanent combining of two (or more) parts that involves melting and subsequent solidification of the material from two parts thus forming a strong joint between them. The assemblage of parts is called a weldment. There are two groups of welding processes according to the state of the base material during the welding process:  Fusion welding.  Solid-state welding. Fusion welding Is by far the more important category. In fusion welding, the base material is heated to melt. The most important processes in this group fall in the following categories: http://www.iaeme.com/IJMET/index.asp 1982 editor@iaeme.com
Noori Hasson Mohammed Al- Saadi  Oxyfuel gas welding: an oxy fuel gas produces a flame to melt the base material;  Arc welding: heating and melting of the material is accomplished by an electric arc between the electrode and base metal.  Brazing and soldering: which involves heating the joint to a definite temperature and using filler metal that melts at a temperature less than the base metal melting temperature. [1] Figure 1 Shows the represent welding process [2] 1.2. Welding joint Types  Lap Joint: Lap welding joints are used most often to joint two pieces differing thicknesses together. Also considered a fillet type, the weld can be made on one or both sides. A Lap Joint is formed when 2 pieces are placed in an over lapping pattern on top of each other.  Edge Welding Joint: Edge welding Joints are often applied to sheet metal parts that have flanging edges or are placed at a location where a weld must be made to attach to adjacent pieces. Being a groove type weld, Edge Joints, the pieces are set side by side and welded on the same edge. For heavier applications filler metal is added to melt or fuse the the edge completely and to reinforce the plate.  Butt Joint: Being the universally accepted method for attaching a pipe to itself it’s also used for valves, flanges, fittings, and other equipment. A butt welding joint is also known as a square grove weld. It’s the easiest and probably the most common weld there is. It consists of two flat pieces that are side by side parallel. It’s a very affordable option 1.3. Friction Welding Traditionally, friction welding is carried out by moving one component relative to the other along a common interface, while applying a compressive force across the joint. The friction heating generated at the interface softens both components, and when they become plasticized the interface material is extruded out of the edges of the joint so that clean material from each component is left along the original interface.[1] Friction welding is defined by the different authors by adopting various definitions of friction welding. The friction welding is a solid state welding process or the method of manufacturing for joining different types of metals, i.e., ferrous metals and non ferrous metals (dissimilar metals) [6] Friction welding technologies convert mechanical energy into heat at the joint to be welded. Coalescence of metals takes place under compressive contact of the parts involved in the joint moving relative to one another [7] Friction welding (FW) is a fairly recent technique that utilizes a non-consumable welding tool to generate frictional heat and plastic deformation at the welding location, there by affecting the formation of a joint while the http://www.iaeme.com/IJMET/index.asp 1983 editor@iaeme.com
The Effect of Tool Geometry on Welding Joint Quality for Aluminum 1100 material is in solid state The principal advantage of friction welding, being a solid state process, low distortion, absence of melt-related defects and high joint strength, even in those alloys that are that are considered non-weldable by conventional welding techniques. Furthermore, friction welded joints are characterized by the absence of filler-induced problems or defects, since the technique requires no filler, and by the low hydrogen contents in the joints, an important consideration in welding steel and other alloys susceptible to hydrogen damage [1] . 1.4. Friction Welding Types There are different types of friction welding process which are classify according to the appearance date in which each technique depend on the kind of welded parts shape and geometry . 1.4.1. Rotary friction welding Rotary friction welding was the first of the friction processes to be developed and used commercially. There are two process variants: direct drive rotary friction welding and stored energy friction welding. The first one is the most conventional technique and usually is simply known as “friction welding”. It consists in two cylindrical bars held in axial alignment. The moving bar is rotated by a motor which maintains an essentially constant rotational speed. The two parts are brought in contact under a pre-selected axial force and for a specified period of time. Fig (2) explains the different stages of rotary friction welding. [7] Figure 2 The different stages of rotary friction welding process. [8] 1.4.2. Radial friction welding Figure 3 Radial friction welding involves rotation and radial compression of a solid beveled ring into a V-preparation provided by the pipe ends The pipe ends are butted together and clamped securely to stop them rotating or moving apart. A mandrel is located in the bore, at the weld location, to prevent collapse of the pipe ends http://www.iaeme.com/IJMET/index.asp 1984 editor@iaeme.com
Noori Hasson Mohammed Al- Saadi and penetration of upset metal formed during the weld sequence. the ring, made from a compatible material, is more sharply beveled than the pipes to promote metal flow from the base of the weld preparation. This also reduces the initial torque demand normally associated with the start of the friction cycle, when cold surfaces come into contact.As with other friction welding processes, no additional filler material is used and welding takes place in the solid phase, i.e. no macroscopic melting is observed. Radial friction welding has also been demonstrated for attaching ductile bands to projectiles and producing wear resistant surfaces on shafts. [8] The LFW process. LFW has been considered as a green technology due to its excellent joining quality and high energy efficiency. Figure 4 Shows the basic principle of linear friction welding process 1.4.3. Friction stir welding Friction stir welding (FSW) which shown in Fig.4, is a solid-state welding process that gained much attention in research areas as well as manufacturing industry since its introduction in 1991. For almost 20 years, FSW has been used in high technology applications such as aerospace to automotive till high precision application such as micro welding. The main feature of a solid-state welding process is the non-melting of the work material which allows a lower temperature and a lower heat input welding process relative to the melting point of materials being joined. This is advantageous over the conventional fusion welding where excessive high heat input is required to melt the work material. [6] Figure 5 Shows the basic principle of stir friction welding process. [9] The process uses a spinning, non-consumable tool, similar to a taper reamer, to generate frictional heat in the work piece. By pressing this tool into contact with a seam to be welded, the base metal heats up and once it reaches about 80% of its melting point it becomes soft and deforms easily. By keeping the tool rotating and moving it along the seam to be joined, the softened material is literally stirred together forming a weld without melting. These welds require low energy input and are without the use of filler materials and distortion. Initially http://www.iaeme.com/IJMET/index.asp 1985 editor@iaeme.com
The Effect of Tool Geometry on Welding Joint Quality for Aluminum 1100 developed for non-ferrous materials such as aluminum, by using suitable tool materials the use of the process has been extended to harder and higher melting point materials such as steels titanium alloys and copper and etc. [9] 1.4.4. Friction Stud Welding In early 1998, friction stud welding was performed commercially at a depth of 1,300 feet (394m) and involved the friction welding of anode continuity tails to riser base piles using a work-class ROV. The friction welding equipment used was a Circle Technologies HMS 3000, which is hydraulically-driven, electronically-controlled, and rated to a depth (910m). Based on this concept, the Naval Sea Systems Command (NAVSEA) initiated another program to evaluate underwater friction stud welding for use in submarine rescue. The program required interfacing the HMS 3000 friction stud welder with the Navy's atmospheric diving suit (ADS), rated to(606m).The feasibility of this concept was demonstrated in 2001 by Oceaneering International using their WASP ADS and the HMS 3000 friction stud welding system. Friction stud welding provides the capability to weld a pattern of studs to the hull of a disable submarine, to which a pad- eye can be attached for the SRC haul-down cable and life support gas can be provided by means of a hot tap process using hollow studs. [7] 1.4.5. Linear Friction welding Linear friction welding (LFW) is a kind of solid state joining technique that was developed in the last 80s. A British patent issued in 1969 described a linear reciprocating mechanism for welding mild steel, although no further information was published. In the early 1980s, TWI demonstrated the viability of the LFW technique for metals using modified equipment. The design and build of a prototype electro-mechanical machine with a linear reciprocating mechanism followed in the mid 1980s. Two similar machines are now located at an aircraft engine manufacturer in Europe. Several other machines of alternative designs are operating in the USA and Europe. [7] During the process of LFW, joining parts move relatively to each other in a linear reciprocating mode under a certain pressure. The mechanical energy is partially transformed into heat by the friction and plastic deformation of the two moving parts. The energy transformation and plastic deformation contribute to the joining of the materials during the LFW process. LFW has been considered as a green technology due 1.5. Aluminum 1100 Aluminum has a density of only 2.7 g/cm, approximately one-third asmuch as steel (7.83 g/cm3). One cubic foot of steel weighs about 490 lb; a cubic foot of aluminum, only about 170 lb . Such light weight, coupled with the high strength of some aluminum alloys (exceeding that of struc-tural steel), permits design and construction of strong , light weight structures that are particularly advantageous for anything that moves—space vehi-cles and aircraft as well as all types of land- and water-borne vehicles.[5] 1.6. Work pice Aluminum (1xxx series) of 99.00% or higher purity has many applica-tions, especially in the electrical and chemical fields These grades of alu-minum are characterized by excellt corrosion resistance, high thermal .[5] Table 1-1 Main process parameters in fricton stir welding [4] http://www.iaeme.com/IJMET/index.asp 1986 editor@iaeme.com
Noori Hasson Mohammed Al- Saadi 2. EXPERIMENTAL WORK 2.1. Material  Work piece material: aluminum 1100.  Tools material: high speed steel.  Work piece dimension : (130*60*6) mm3‫ز‬  Tools dimension: shoulder diameter is 16mm & circumference for triangle & square pins is 18.84 mm. 2.2. Work piece & tools machining  The plate parts were cut by punch cutter to the desired dimension and by using sand paper to clean the plate surface from oxide layer in order to get good surface convienent to the friction stir welding  The tools were manufactured by the following steps:- 1. The raw material was cut by disk cutter with dimensions ∅20 * 80mm. 2. By using lathe machine the following step are:-  Facing to modify the face.  striaght turning to get ∅16 mm L=70mm .  Striaght turning to get ∅13 mm and L=35mm . http://www.iaeme.com/IJMET/index.asp 1987 editor@iaeme.com
The Effect of Tool Geometry on Welding Joint Quality for Aluminum 1100  Reverse the part & clamp the part by the chuck.  Facing to fixed the length of the part L=70mm. 3. Heat treatment :heating the parts to 900℃ and quenching by oil to room temperature to get high hardness followed by tempring process to avoid brittlness. Table 2.1 The main conditions used in the experiments W/rpm Depth ∅ Tool /type V/mm/min 800 3.4 20 Triangle 30 1000 3.4 20 Triangle 30 1200 3.4 20 Triangle 30 800 3.4 20 Square 30 1000 3.4 20 Square 30 1200 3.4 20 Square 30 Figure 6 (a) Top side similar Fs butt joint of A A100 at rotational speed 1000 rpm and welding speed 30mm/min, (b)back side Figure 7 Tachometer device used to measure machine RPM http://www.iaeme.com/IJMET/index.asp 1988 editor@iaeme.com
Noori Hasson Mohammed Al- Saadi Figure 8 Spindle speed measurement Figure 9 Friction stir welding (Clamping, fixture) for the work piece Figure 10 Friction stir welding process by Milling Machine Figure 11 Square tool Figure 12 Triangle tool used in used in the present work the present work http://www.iaeme.com/IJMET/index.asp 1989 editor@iaeme.com
The Effect of Tool Geometry on Welding Joint Quality for Aluminum 1100 3. RESULT AND DISCUSSION 3.1. Introduction This chapter includes the results and discussion of AA1100.Many weldments were done using tools made of tool steel with two types Square and Triangle. with a rotating speed range of 800,1000,1200 rpm, and feed speed range 30 mm/min were investigated . Two groups were studied for similar welds of alloys AA1100 welds made from aluminum alloys. More focus was on the second group due to their wide applications. Destructive and non-destructive tests were done to these groups as will be explained. Effect of tool design on the joint efficiency For these results, comparison was done between these samples which is a similar weld of 1100 alloys weld with Square tool and Triangle tool Both samples were welded with rotational speed of 800,1000,1200 rpm, & constant feed rate of 30 mm/min. For the same parameters the tool plays an important role in increasing the weld efficiency. 3.2. Similar welds Tensile test results for this case 1 which includes the use of tool steel with Square & Triangle profile design to weld similar 1100 alloys give a small indication when increasing both tool rotation speed and constant feed. These results show a moderate efficiency in terms of tensile strength, in spite of getting the maximum Tensile strength by using a Square tool & rotational speed of 1200 rpm and feed rate of 30 mm/min, which means a high heat rate input at high rotational speed and low feed as shown in Figure. For case 2 which includes the use of Square tool was made to increase the flow of metal during welding for similar 1100 alloys; a low efficiency was reached for these joints at 1000 rpm & 30 mm/min. This may be attributed to the inappropriate rotational speed. For case 3 which includes the use of with round edges Triangle tool, maximum tensile strength appear at feed of 30mm/min and 1000 rpm for alloy were reached by using the while minimum tensile strength appear at feed rate 30mm/min and 1200rpm .Which is shown in Fig. 3.3. Nondestructive Testing (NDT) Visual Inspection Visual inspection is the simplest and first diagnosis of the weldment surface (like misalignment and flash) or cross section view (like voids, porosity, cracks and other defects).. These defects are visible to the naked eye which resulted from applying inappropriate travel speed (mm/min.), rotational speed (RPM), plunge force load and tilt angle. 3.4. Destructive Testing ( NDT ( Tensile Test Results Tensile test were done in this study as following : Similar welds of alloys AA1100 were performed These welded joints are illustrated in Table ,Effect of tool design on the joint efficiency For these results, comparison was done between two samples the first under Square tool & the other under Triangle tool; which is a similar weld of 1100 alloys, Both samples were welded with rotational speed of 800,1000,1200 rpm, feed rate of 30 mm/min. For the same parameter the tool plays an important role in increasing the weld efficiency in addition to the effect of materials. http://www.iaeme.com/IJMET/index.asp 1990 editor@iaeme.com
Noori Hasson Mohammed Al- Saadi Figure 13 Load-Extension curve of stir welded specimen of AA1100 plates 6mm thick welded with square tool at above conditions. Figure 14 Load-Extension curve of stir welded specimen of AA1100 plates 6mm thick welded with square tool at above conditions. Figure 15 Load-Extension curve of stir welded specimen of AA1100 plates 6mm thick welded with square tool at above conditions. Figure 16 Load-Extension curve of stir welded specimen of AA1100 plates 6mm thick welded with Triangle tool at above conditions. http://www.iaeme.com/IJMET/index.asp 1991 editor@iaeme.com
The Effect of Tool Geometry on Welding Joint Quality for Aluminum 1100 Figure 17 Load-Extension curve of stir welded specimen of AA1100 plates 6mm thick welded with Triangle tool at above conditions. Figure 18 Load-Extension curve of stir welded specimen of AA1100 plates 6mm thick welded with Triangle tool at above conditions. Figure 19 Effect of rotational speed on max tensile load of similar metal weld at feed rate 30mm/min using Triangle tool Figure 20 Effect of rotational speed on max tensile load of similar metal weldat feed rate 30mm/min using square tool http://www.iaeme.com/IJMET/index.asp 1992 editor@iaeme.com
Noori Hasson Mohammed Al- Saadi 4. CONCLUSIONS AND RECOMMENDATIONS FOR FUTURE WORK 4.1. Conclusion Conclusions The following conclusions can be withdrawn :  Tool design and geometry show noticeable effect in improving the mechanical properties of FSW joints for similar alloys (AA1100).  Square pin tool work much better than Triangle pin tool at all rotational speed 800,1000,1200 and 30 mm/min Feed rate.  Best tensile strength properties were obtained using tool design of Square geometry.  The best joint strength was obtained using tool rotational speed of 1200 rpm, feed rate of 30 mm/min., tilt angle (Ɵ) of 2o and clockwise tool rotation direction and by placing two plates AA1100 butt joint between them.  At high RPM and low feed rate under these condition the heat generated by pin & shoulder for Square tool was high that improve the joint quality. 4.2. Recommendations for future work  Study of the joint quality of dissimilar Aluminum alloys and make comparison between joint quality but with different friction stir welding parameters.  Using another tool geometries for example (cylindrical, cone, cylindrical threaded……etc.)  Using another Aluminum plate thickness and different tool length. REFERENCES [1] Dr. Pulak M. Pandey, Welding and Allied Processes. [2] Automatic identification of different types of welding NDT&E International December 2002. [3] Modern welding technology (fourth edition) © 1998, 1999,2001 by Howard cary simon and Schuster Viacom company upper saddle - river, new Jersey 07458. [4] Viacom Company - A Viacom Kumar R, Ghost A, Chattopadhyaya (2014) Emerging friction stir welding for aluminium and its applications. [5] Light Metals and Alloys 2001 ASM International® [6] Ranjan Sahoo and Pinaki Samantaray, Study of friction Welding, National institute oftechnology,Rourkela,India, 2007. [7] Livan Fratini, Gianluca Buffa, Marco Cammalleri, Davide Campanella, On the linear friction welding process of aluminum alloys: Experimental insights through process monitoring, CIRP Annals - Manufacturing Technology 62 (2013) 295–298. [8] Lee S Smith, Philip Threadgill & Michael Gittos TWI, A Designer & user hand book,1999. [9] Kwanghyun Park, Development and analysis of ultrasonic assisted friction stir welding process, PhD thesis University of Michigan, 2009. http://www.iaeme.com/IJMET/index.asp 1993 editor@iaeme.com