Influence of Various Wood Species and Cross-Sections on Strength of a Dowel Welding Joint

Rotation welding is a new method used in wood welding. Heat that develops due to the friction on contact surfaces softens and melts the wood structure (melt is produced). When the friction stops, the melt cools down and solidifies forming a firm joint. This research is based on the examination of the influence of various wood species and cross-sections on the strength of joints produced by rotational welding. Using rotation frequency and shifts in the orientation of the horizontal axis, a beech dowel is welded to a base made of common beach (Fagus sylvatica L.), pedunculate oak (Quercus robur L.) and Norway spruce (Picea abies L.) (hereinafter only beech, oak and spruce). Welding direction is both parallel to the orientation of the base fibres (PP) and perpendicular to the orientation of the base fibres (R, RT, T). Research results indicate that the dowel welded to the beech base retains the largest strength, whereas the dowel welded to the spruce base reveals the weakest results. Based on the research results, it can be concluded that beech dowels welded in the direction of beech and oak bases have the best strength of a joint. In spruce samples, reaction wood was used (compression wood in conifers) with somewhat different distribution of strength depending on the welding direction.