Effect of process parameters during friction coating on properties of non-dilution coating layers

Few surface modification processes appear to coat a 1 mm thick compact layer on a substrate successfully, although several technologies have been proposed and applied. The present paper concerns a fundamental approach to establishing a friction surfacing technique that produces a 1mm thick hard coat. Experiments were carried out to clarify the effect of process parameters on the quality of coatings. Martensitic stainless steel with 1C-17 Cr was the coating material and low carbon structural steel the substrate, using a conventional friction welding machine equipped with a sliding stage. A 20 mm wide and 1 mm thick stable hardened layer was produced using a 20 mm dia. Rod of coating material. The dimensions of the layer depend on the rotational speed of the consumable rod, as lower rotational speeds produce thicker, wider coating layers. Calorimetric measurements revealed that the total heat input rate was not influenced by the frictional speed, however the ratio of thermal distributions on to the substrate and rod was significantly affected by rotational speed. Additional experiments were carried out to clarify the effect of edge preparation, rotational direction, and overlapping distance on defect formation in multilayer depositions by friction coating for wide area coating on steel plates. Results were optimised by grinding the edges of previous layers to prevent defects such as incomplete bonding.