Surachai Junchana และ Chawalit Thinvongpituk. (2011) The influence of friction time and contact angles in friction welding for Polyethylene pipes. <i>KKU Engineering Journal</i>, <i>38</i>(3), 147-154.Surachai Junchana และ Chawalit Thinvongpituk. "The influence of friction time and contact angles in friction welding for Polyethylene pipes.". KKU Engineering Journal 38 (2011):147-154.Surachai Junchana และ Chawalit Thinvongpituk. The influence of friction time and contact angles in friction welding for Polyethylene pipes. Faculty of Engineering, Khon Kaen Univeristy:ม.ป.ท. 2011.