Research On Key Technologies Of Friction Hydro Pillar Processing

As an important branch of friction welding field, Friction Stitch Welding is a new type of repairconnection technology. Since Friction Stitch Welding was first propose by The Welding Institute inthe1990s, it has begun to attract attention of scholars from various countries. Friction stitch weldingtechnology has the advantages of high welding quality, no pollution and construction conditions, so itcan be effectively used in the repair cracks. As the basic forming unit of Friction Stitch Welding,Friction Hydro Pillar Processing directly affects the quality of the friction welding. So it is importantfor the study of Friction Hydro Pillar Processing.According to the forming process, the welding device was designed based on Friction HydroPillar Processing. It mainly consists of three parts: the mechanical structure, frequency controlmodules and data acquisition systems. It can provide the welding rotational speed and the weldingfeed speed. It also can collect and record the related data during the experiment.Based on the forming principle of the initial stage, the mathematical model of the7075-T6super-hard aluminum alloy was establish and its numerical simulation of temperature field wasanalyzed, the simulation results show that: an appropriate increase in the welding rotational speed andthe welding feed speed can help improve the speed of the rate of rise of temperature during thewelding, which contributes to reducing defects in the initial stage and improving the welding quality.At the same time it established the flow analysis model based on the stable phase of Friction HydroPillar Processing, and analyzed the impact of feed speed、rotational speed and gap value of the model,simulation results show that: an appropriate increase in the feed rate can be increased at the bottom ofthe model pressure value, but more than a certain value, the feed rate of the impact pressure at thebottom of the model is relatively small; increasing the rotation speed of the model can effectivelyincrease the pressure; flow velocity field is largely determined by the rotation speed; the gap valuebetween the rob and aperture is too large to cause the value of the low model pressure.The series of Friction Hydro Pillar Processing experiments base on7075-T6super-hard aluminumalloy were test by using self-developed welding device. And it analyzed the parameters affect theexperimental results, such as welding rotational speed, welding feed speed and gap values of themodel. The experimental results show that the: improving the rotational speed and feed speed willhelp improve the quality of welding forming and reduce weld defects; gap value of the model is toolarge to easily appear the situation incomplete penetration at the bottom of the model; underreasonable conditions of process parameters, the welding zone grain is very small, and hardness valueof the welding zone can reach90%of the parent material; according to the experimental data, theresult of the simulation is verified in some extent.