Thermomechanical butt fusion welding of HDPE pipes is highly sensitive to variations in welding parameters and conditions. To date, researchers have all confirmed the change in flux and molecular chain orientation from axial to radial. They explained the decrease of certain mechanical properties to this change in orientation. This change is mainly due to thermal and mechanical stresses applied in standard welding cycle. The main idea of this paper is changing process in order to minimize the mechanical stresses of the welding phase. The procedure is to monitor and regulate position instead of pressure. We opted to carry out the tests according to two closely linked DOE experimental plans, the output of the first plan (DOE-1, controlled force) allows the definition of the second plan (DOE-2, controlled displacement). A tensile test, an ultrasonic inspection and a MEBE characterization images are realised in order to identify the results of the procedure change.