Effect of environment on corrosion characteristics of newly developed DMR-1700 structural steel

Abstract

The corrosion resistance of any metallic material depends on the environment to which it is exposed. DMR-1700 steel is a material for structural applications that has been recently developed at Defence Metallurgical Research Laboratory by changing the chemistry of alloying elements. Therefore, a detailed understanding of its corrosion characteristics under different environmental conditions is essential. In the present paper, we report the results of a systematic corrosion study that was carried out on the new steel to determine the effect of the environment on the protective nature of the oxide scale that forms on its surface under different environmental conditions. Furthermore, the oxide scale as well as the resistance to pitting and crevice corrosion were studied in various environments. The surface morphologies of the corroded steels were observed under a scanning electron microscope (SEM) to determine the nature of the corrosion. On the basis of studies by different techniques, DMR-1700 steel is recommended for the manufacture of components used in various systems in conjunction with the application of an appropriate protective coating to improve its resistivity to corrosion.

Failure analysis of a 34CrMo4 seamless steel gas cylinder filled with a mixture of fluorine and nitrogen gases

“…Figures 10 and 11 clearly present evidence of burning, which resulted in the melting and solidification as seen around the edges of the fractured hole of the cylinder. The images of the fractured surface shown in Figure 10 evidently indicate the presence of environmental attack that originated from the burning of the steel [14]. The fluorine attacked on the steel leading to burning is exhibited by the fractured surface confirming the steel's ability to readily burn in fluorine atmosphere as observed in this investigation [9].…”

“…Figure 4 shows an image of the fractured surface of the failed cylinder with a series of gouge marks. The surface of the gouge marks are dark-coloured indicating the effect of an environmental attack in the form of burning and corrosion [14].…”

Effect of Natural Sources on the Corrosion Inhibition

“…All metal structures undergo some degree of corrosion in the natural environment [5]. Bronze, brass, stainless steel, zinc and aluminum materials can last longer without protection [6].…”