Failures in heat exchangers due to corrosion - (A case study on a chemical fertilizer plant)

In this investigation, 64 tubes of two different steels, differently surface treated by Tufftriding (15, 27 & 37 mum case depth, and 56 HRC case hardness) and Carburizing (0.8, 1 & 1.2 mm case depth and 40, 45 & 50 HRC case hardness), were grouped and used as the bundle of a heat exchanger-like test rig. The tubes were exposed to the same conditions simulating an actual heat exchanger in the plant with a total exposing time of 3360 hrs. The corrosion rates were calculated using the "loss of weight" technique. The results showed that the rate of corrosion was lowered by different percentages depending on the conditions of heat treatment used, and that Tufftriding caused the service life of the tubes extended by a factor of 1.5-2.