Experimental research of the corrosion behaviour of the coating materials used in diffusers of sugar plants

In this study, the corrosion behavior of the base material and the material of austenitic stainless steel coated onto the base material by means of encapsulation method, used in the diffuser unit, one of the most important units of the sugar plants where slivered sugar beet is delivered after being scalded and converted to raw juice is analyzed. Corrosion experiments were performed according to the mass-loss method and the duration of subjecting the samples to corrosion was determined as 2, 4, 6 and 8 hours. The materials used in the experimental study are St-37 Low Alloy Steel which is the base material of the diffuser and Type AISI 304, AISI 304L and AISI 316 of the austenitic stainless steel group coated onto the base material by means of encapsulation method and compounded by welding. The samples used in the experiment were obtained by purchasing from the material market. The samples were divided into two groups ? heat treated and non-heat treated. Heat treated samples were subjected to homogenization process after being maintained for 10 minutes at 11000C. In order to determine the corrosive effect of the acidic juice environment in the diffuser on the samples, SEM-EDX, X-Ray Diffraction, micro-hardness and surface hardness tests were applied to the samples.As a result, it is observed that the corrosion resistances of all samples are improved after the homogenization heat treatment applied at 1100 0C. In addition to that the best result regarding the corrosion resistance among the 4 types of material including St 37 low alloy steel is observed in the sample made of AISI 316 austenitic stainless steel.Keywords: Sugar Plants, diffuser, corrosion, austenite, stainless steel.