Effect of parameters of the butt pressure welding process on the strength and ductile properties of polyvinylidene fluoride – PVDF – tubular joints

Abstract

The method most often used for permanent joining of thermoplastic elements is that of butt pressure welding. So far, the investigations carried out at Instytut Spawalnictwa (The Welding Institute) have been focussed on the assessment of the quality of joints made in basic grades of thermoplastics, such as polyethylene (PE), and polypropylene (PP) by the fusion and pressure welding processes, and also, on the technology of these methods. These particular materials are widely used in a variety of plastic constructions such as gas, water and drain pipelines, chemical installations, installations for desulphurisation of combustion gases in power plants, and so on. As the use of plastics for more specific constructions increases, new materials of enhanced properties appear. They are characterised by their higher degrees of purity, a wider range of working temperatures, higher strength, resistance to ultraviolet radiation, etc. Polyvinylidene fluoride (PVDF) belongs to this group.