Linear Friction Welding of High Strength Chains

Title: Linear friction welding of high strength chains

Abstract Text:
Flash butt welding is the common process for the welding of big diameter steel chains. This process has been used for many years, and it is successfully applied for different profiles and dimensions of chain links. However, this process yields low production, due to relatively long cycle time. Due to the heat input of this fusion welding process the material becomes liquid, what induces significant changes in the microstructure in a wide area and makes post-weld heat treatment and an expensive quality control necessary.
Through detailed analysis and a subsequent evaluation of seven alternative welding processes a worldwide completely new and innovative approach for welding of chains has been found. Linear friction welding (LFW) is a solid state joining process in which a stationary part is forced against a part that is moving in a linear transverse direction and the heat is generated due to frictional heating at the weld interface. Instead of one weld in each link in the conventional flash butt welding process in linear friction welding two half links are joined with two welds maintaining a much smaller heat affected zone and making the use of different geometries and materials of the chain possible.
This study describes results of the basic research on the linear friction welding of 23MnNiMo5-4 high strength chain steel including the microstructural and mechanical characterization of three different chain link diameters (12, 15 and 18 mm) in dependence of the applied welding parameters revealing the basic dependence of product quality and applied welding parameters.