2011 Volume 29 Issue 4 Pages 319-325
The purpose of this study is prevention of generation of polyethylene dust when pipe is jointed by friction welding. The joining specimen is changed from I butt welding to taper faying surface, polyethylene is softened rapidly in the initial friction by wedge effect. Furthermore, an effect of a mud on joining phenomena is examined, when large amount of the mud is adhered to faying surface since the mud adhere to faying surface during gas and water piping works.;
The experimental results are as follows;
1) Polyethylene of faying surface was softened very rapidly (about 0.1s). This main reason was wedge effect for taper faying surface.
2) Time that dust was generated was remarkably short, and quantity of dust was little. This dust remained at the tip and inside of faying surface, subsequently it was melted with molten polyethylene of faying surface and the dust was not observed inside of the pipe.
3) In the case of taper angle was 5°, arrival time to initial torque was extremely early. Steady torque was increased slightly as the taper angle was decreased.
4) A large amount of the mud was pushed out from faying surface. This mud was shaved by faying surface when it combined rotation and fixed side before friction welding. Remaining mud was mixed with molten polyethylene so that inside of the pipe was not dirty.
5) Tensile strength and elongation of the welded joint that mud was adhered were 24.0MPa and 503%, respectively. These were nearly equal to those of the clean welded joint. Therefore, rapid and low cost joining without dust was enabled by using taper faying surface.
