Friction welding receives behavior of flow of head plasticity metal to study the current situation
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The foil of tall purity Cu of 1mm, solder hind undertakes microstructure observes, the experiment makes clear shed a condition of going from place to place to basically be comprised by 2 processes, the first process basically is metal of ahead of needle of ongoing side agitate as agitate needle direction of rotation rotates ongoing, metal of going from place to place gets the action of agitate needle thread and flow downward, backfill arrives ongoing side, the metal that another process is regressive side flow is squeezed to go out to advance with fill side. The material sex difference that 2 processes form severally is bigger, consequently civil get the verdict related flow of metal of the plasticity inside welding line function and welding line. As the big range application of composite material, investigator considered to use composite material to make mark material, if London uses Al-SiCp and Al-W composite material,serve as the material that show trace to received flow of 7075Al-T7451 material plasticity to undertake study to agitate friction welding. Experimental result makes clear, the material that is located in agitate needle ahead is risen apparently by tool dip action, metal of welding line ahead arises " plow agrarian behavior (Ploughing Action) " . The material that show trace is all round agitate needle happen cut, and be down to squash at the same time by the action of axial shoulder. London makes clear, in FSW material deflection depends on the relative position with agitate needle, side of welding line advancement shows footprint material distributinging extent relatively part of welding line center is wide. The research that Nextpage home flows to material plasticity starts later, the research technique in current document cites more experimental method of abroad, for example, xing Li agitate attrition technology that adopts research 2014Al alloy reachs an organization, to material plasticity flow undertook series figures. The report points out, direction of flow of metal of plasticity of the advanced welding line that take side and way of flow of metal of plasticity of mother capable person are opposite, make presence very large between metal of mother capable person and welding line metal be out of shape poor, returning direction of flow of direction of flow of metal of plasticity of side welding line and metal of plasticity of mother capable person to agree, metal of mother capable person is out of shape smoothly together with welding line metal. Luan Guogong uses heterogeneous aluminium alloy to build receive means to have test of agitate friction welding, organization of 2 kinds of aluminium alloy is compared to distributing in the position of welding line metal through observation after solder the case of going from place to place that metabolic circumstance decides welding line metal. Research uses red copper to do indicative material and mark to embed the technology studied metal of aluminium alloy plasticity flows respectively configuration. The experiment all got the experimental result of similar Reynolds and Seidel. The flow of metal of welding line of experimental method exploration has an operation the characteristic with simple, direct observation, and obtained certain positive result, but the complexity as a result of process of agitate friction welding, make workload of experimental sum of errors bigger, and can make qualitative analysis to the flow of welding line metal only. At the same time because experimental method cannot see the process that material flows directly and get very big limitation. The development of technology of 2 computers simulation as computer technology, apply analytic the method that builds a model with maths will study the analysis solders the flow of the material in the process makes a kind of important research instrument. Inchoate research uses 2 dimension model to undertake study to data flow more. Document built slip interface and attrition to contact 2 models imitate FSW process, computation forecasted the form of going from place to place of material, computational result and the result be identical that label built-in technology is obtained are better. Smith built model of flow of heating power coupling, this model rotates type of tool geometry, alloy, tool the process of going from place to place that tool position and speed, floating rate regarded input quantity as to calculate data. Colegrove used Fluent of software of hydrokinetics of 2 dimension computation to study the metal near FSW tool flows. The rule of going from place to place that wins rule of going from place to place and London and Guerra experiment to get is almost uniform. Document introduced a kind of numeric imitate and the method that experimental photograph combines in detail. The solid phase that numeric imitate builds is mechanical the stress in feature of flow of the speed field that the model defined to material flows, data and plasticity flow process distributings. Experimental part is to pass visible dog the technology solders certainly the mode of going from place to place of the material of around. Seidel be based on hydromechanical theory to build model of 2 dimension FSW, this model will solder FSW the process considers as laminar flow, agglutinant, non Newton fluid to bypass gyral cylinder agitate head. Material plasticity is out of shape produce heat to make welding line metal produces bate. 2 dimension model forecasted flow of welding line metal to be below most circumstance, material bypasses from regressive side agitate head flows. Be based on behavior of flow of hydromechanical analysis data is cannot accurate report data is soldering of the athletic essence in the process, a few scholars (wait like Zhang Hongwu) use general and finite the agitate process to FSW undertakes yuan of software ABAQUS 2 dimension imitate, considered to solder the condition of going from place to place of material of the weldment in process and soldering the stress of the material in the process and circumstance of meet an emergency. Get the following mode of 3 kinds of flow, namely: After the material of ongoing side winds week of agitate head revolution coming back, deposit is in the wake after agitate head; What the data of regressive side is come back to turn agitate head by agitate head directly is rear; The material that approachs point of intermediate welding line can be entered rotate the area circles agitate head to rotate. Above 2 dimension model is too simple, did overmuch hypothesis, can not represent real FSW flow character. England solders the Smith of the institute summed up simulative of flow of the data in process of agitate friction welding to make progress in document, point out model of three dimensional space of agitate friction welding has practice sense more. The applied business maneuver such as Colegrove calculates imitate of hydromechanical software FLUENT the plasticity of stuff of the metal in FSW process flows, the three-dimensional and slip model that built TrivexTM agitate head and TrifluteTM agitate head. These models announced the three-dimensional flow condition around bougie, forecasted transverse pressure and the pressure that are down direction. But in this model, colegrove did not consider head of agitate head corkscrewed yarn, agitate to tilt shape of coronal of top of the homocentric cirque on shoulder of angle, axis and agitate head bougie is raised the influence that flows to the fluid. The model that the flow that document uses temperature field to be aimed at the complex metal in welding line of agitate friction welding as attrib border condition builds was analysed solder the influence that rotate speed of head of speed, agitate coming back spends pair of models. Reached a lot of soldering the true feature in the process, but this model solders without dope pressure. The experiment before the person basis such as Nandan built three-dimensional metal to stick plasticity flow model, imitate result makes clear, heat of process of agitate friction welding is conducted and data flow is having apparent asymmetry sex, and as solder rotate speed of speed and agitate head coming back spends rise, this kind of asymmetry sex also is increasing. Recently, the person such as Nandan still built agitate friction welding to receive medium carbon steel three-dimensional stick plasticity flows and conduct heat model, the model uses blame Newton agglutinant computation metallic flow, the horizontal streamline that document got different deepness (show 2 times like the graph) , streamline indicated the presence of intimate circle, and for closed streamline, this explains material is put in circumfluence all round agitate needle. Still show data moves to basically happen in regressive side in the graph. The detailed in analysis of behavior of connect of friction welding of aluminium alloy agitate introduction such as domestic Luan Guogong the result that plasticity of connect of agitate friction welding sheds variable to be worth imitate earning to arrive. Fall in shoulder of agitate head axis about 1.
5mm place, the existence in the plasticity fluid structure of side of advancement of agitate friction welding does not stabilize area -- turbulence area. The existence of this turbulence area meets what change metallic stuff badly to transfer way. Wang Dayong in establishing procedure of agitate friction welding thermoplastic the model of physics of behavior of going from place to place of bate area, distinguish plasticity bate it is 3: Near axial shoulder, near agitate needle upside and agitate needle lower end. Adopt a model build and computation reachs 3 material flows feature each are not identical: Because agitate needle is in then all right,the material near axial shoulder is flowed into above all agitate needle is hind inside the cavity that stay, odd material criterion around move axial shoulder flows by ongoing side of agitate head hind; The material near agitate needle upside flows from agitate needle forehead with cut way agitate needle is hind; And the material near agitate needle lower end flows from the forehead of agitate needle with the means of extruding of agitate needle hind. Wang Xijing wait and all use FLUENT fluid project Wang Xunhong to emulated software to undertake numeric computation and imitate to the plasticity flow of metal of welding line of agitate friction welding. Document is initial reached fluid of plasticity of welding line of agitate friction welding flows transverse, fore-and-aft rule. From already in light of some document, it is better to use FLUENT software the plasticity of body of midstream of ground imitate FSW flows, but temperature field cannot very good clarify. In the meantime, because agitate friction welding receives the characteristic of the head, regarding pure fluid also is pair of actual processes is bigger simplify, the outcome is not quite ideal also. Document used ABAQUS software to build be based on nonlinear successive medium is mechanical and finite yuan of model, the data that studied the agitate friction welding below different parameter receives a condition to fall flows, imitate result makes clear, ongoing side puts welding line in eddy, and rate of flow of the data in eddy increases as the addition of floating rate. 3 physics model is the closest, use clay Liechty first (Plasticine) studied behaviour of flow of plasticity of metal of agitate friction welding as physical analogue. The blame vulcanization clay that different hardness used in document (NFP) , the experiment makes clear can obtain relative to softer clay flawless welding line, its flow characteristic similar also metal. Although clay is the material of a kind of indeterminate form, organization of its welding line and metallic organization are different, but its and metal have identical hot content sex, consequently can qualitative analysis and duplicate agitate friction welding accept deed of flow of process metal stuff. Use different color at the same time and the clay with same function can regard label material as visible data flow. Liechty further research was done to flow of plasticity of material of argillaceous physics imitate in document, through buy is being buried in clay little steel ball is mixed process of flow of data of attrition of agitate of research of ration of particle reseau law. The experiment obtained agitate needle through particle reseau law the greatest strain of around material and rate of meet an emergency, it is respectively 4.
4 with 1.
3s-1. Experimental result still makes clear, workpiece material and agitate needle surface are sliding contact, and the 6%~7% that the oldest rate of material of proximate agitate needle is agitate needle speed. Although the experimental research that the last word flows to metal of plasticity of the connect in friction welding process obtained certain result, but because the complexity of friction welding process is mixed,cannot see directly solder of the material in the process flow and get very big limitation. As the development of computer technology, apply numeric simulative method to study the analysis solders the flow of the material in the process has wider perspective. To friction welding plasticity the numeric imitate of process of going from place to place conduces to the deep understanding that receives mechanism to friction welding, but because friction welding is a very complex process, the parameter of sex of a lot of hot content related to its still is lacked very much, make numerical value of attrition plasticity flow considers to still be faced with a lot of and difficult thereby. But we believe, the development as computer technology and deepen further to what friction welding studies, the development that imitate of numerical value of friction welding process is sure to be able to be friction welding technology and application provide new power. CNC Milling