An analytical model for predicting residual stresses in multiple layers by plasma cladding process

Abstract

An analytical model is developed to predict residual stresses formed during plasma cladding process. This is based on the force and moment balances and misfit strain caused by differential coefficient of thermal expansion (CTE) of substrate and cladding layers during cooling. The model can be implemented by a simple programming. Residual stresses can be predicted from a knowledge of material properties, temperature of substrate and layers and specimen dimensions. Residual stresses are calculated after each layer rather than as a whole. Specific results can be obtained for the distribution of residual stresses within Co-based layers system. The effect of temperature of substrate and layers, the number of layers, the curvature of a composite beam on the residual stresses are discussed. It has been found that the residual stresses decrease with the increase of preheating temperature of substrate and inter-layer temperature of layers. The curvature increase with increasing layer number.

A Study on the Residual Stress of the Co-Based Alloy Plasma Cladding Layer

“…Plasma cladding technology is an advanced surface modification and repair technology, the principle of which is to use high-energy plasma beams to melt the substrate with its surface metal powder by heat and form a solid metallurgical coating after rapid solidification, thus substantially improving the performance of the substrate [ 5 , 6 , 7 , 8 ]. Due to the process characteristics of rapid heating and cooling of the molten pool part in the plasma cladding process, the rapid cooling of the layer and the difference in thermal expansion coefficients between the substrate and the clad layer can cause accumulated residual stresses, and the larger tensile residual stresses induce fatigue cracks, reducing the wear resistance and peeling resistance of the clad layer [ 9 , 10 ], causing deformation and cracking of the substrate [ 9 ] and affecting the subsequent mechanical processing of the substrate and its serviceability and life [ 11 ]. Therefore, it is of great significance to study and to regulate the distribution law of residual stress in plasma cladding.…”