Saint Petersburg State Polytechnical University, Saint Petersburg, Russia:

Rudskoy A. I., Head of University, e-mail: rector@spbstu.ru
Naumov A. A., Assistant Professor of a Chair of Technology and Research of Materials
Chernikov E. V., Engineer of a Chair of Technology and Research of Materials

This article considers a new method of severe plastic deformation (friction stir processing), based on the friction stir welding process. This process was patented in 1991 by The Welding Institute (TWI). The first stages to this invention were made in USSR in 1967 (according to the friction stir welding). Invention certifi cate number is 195846. There are presented the principal scheme and main stages of the process (such as plunging, dwelling, stir welding and pulling). The foregoing processes are briefly described. Processed metal microstructure is shown schematically. There was defined that recrystallization in stir zone occurs with significant grain refinement, when intensive interaction between spinning tool and metal takes place during processing in premelting state. Tool virtual model was created in the Solid Works program and was imported to the licensed Finite Element Model program Deform 3DTM, which allows to forecast the material flow behavior and temperature fields distribution during processing. The Process Finite Element Model with adaptive remeshing parameters was developed, according to the complex metal motion during plunging. Temperature distribution in processed area in cross and longitudinal sections during plunging was calculated with the help of numerical simulation. There was established that nonuniform temperature is distributed in the processed area. Signifi cant increase of temperature in plunging stage is started with the contact of shoulder on the metal surface. There is observed a small temperature field difference between advancing and retreating sides.

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