Influence of Cross Section on the Parameters for Linear Friction Welding of High-Strength Chains

In respect of weld quality, weld strength and the heat affected zone (HAZ) size, linear friction welding (LFW) has significant advantages compared to flash-butt and resistance welding. The production of chain links is realized by one c-shaped part in reciprocating motion being moved towards a stationary one under applied forces. The friction at the contact faces causes heat and thus, the material is plastically deformed. Due to relative movement excessive material is pressed out of the joint area leading to a characteristic weld burr. Relative motion is stopped once the defined burn-off is reached and by applying the forge force the chain is welded. In this paper, welding parameters for three different cross sections are investigated. Based on successful welding trials on 30CrNiMo8 steel chains with 26 mm diameter, parameters are adapted for smaller cross sections. On 48 steel specimens with 7, 10 and 15 mm diameter systematic welding trials are performed. The influence of the welding parameters frequency, amplitude, forge force and burn-off on welding strength and welding time are investigated with and without application of heat treatment. This test series was evaluated using DoE.