Ethanolic Media Effect on the Susceptibility to Stress Corrosion Cracking in an X-70 Microalloyed Steel with Different Aging Treatments

Adrian Del Pozo,Heriberto Villanueva,Julio César Villalobos,Sergio Alonso Serna Barquera,Jose Gonzalo Gonzalez Rodriguez,Alvaro Torres,Amilkar Fragiel

doi:10.3390/en13123277

Abstract

The objective of this research was to evaluate the stress corrosion cracking (SCC) of X-70 micro-alloyed steel in contact with bio-ethanol and E-50 gasohol. Environmental factors, including water (1%, 3% and 5%) and NaCl (10 mg/L and 32 mg/L), as well as two aging treatments were studied. Experimental values were obtained by the Slow Strain Rate Test (SSRT) technique, X-ray fluorescence (XRF), and tensile test according to the information reported in the literature. The results of the SSRT for the SCC determination showed that this steel in these conditions did not show evidence of SCC, which was attributed to the formation of an oxide (Fe2O3) not soluble in ethanol. The oxide layer acts as a protector preventing the formation of pitting, one of the main causes of cracks initiation in SCC.

Highlights

The use of fossil fuels plays a major role in climate change due to carbon monoxide emissions.The growth of new technologies solving current and future energy problems has grown in significance, as has the growth of renewable energies including biofuels like bio-ethanol, which has proven to be very useful in reducing greenhouse gases [1,2,3], has a lower energy yield and has lower vapor pressure, suggesting less evaporative emissions, amongst other things [4].In recent decades, there has been an increase in the use of bio-ethanol as an alternative to fossil fuels, in efforts to make the transport method more efficient [5,6]
The increase in ductility in all conditions is attributed to the change in the morphology of the ferritic grain, which was modified from being elongated due to thermomechanical processing to a little more equiaxiated grain, which softens the matrix, conferring an increase in ductility, in addition to a stress relief in the matrix
There are studies that have demonstrated the presence of the stress corrosion cracking (SCC) phenomenon in certain microalloyed steel compositions in different bio-ethanol media, which is attributed the susceptibility of the material to the source of bio-ethanol; corn bio-ethanol is considered a factor that increases susceptibility and cane bio-ethanol shows immunity to SCC [32]

Summary

Introduction

There has been an increase in the use of bio-ethanol as an alternative to fossil fuels, in efforts to make the transport method more efficient [5,6]. Some of the reasons for this increase in the use of bio-ethanol has been the Kyoto protocol and the replacement in the USA of methyl-tert-butyl ether (MBTE) as an octane booster in gasoline, due to its high contaminant potential [7]. Bio-ethanol is transported mainly by tank trucks and railway, and the transportation projects in which high-strength and low-alloy steel pipes (HSLA) have been used to increase optimization, reduce costs, and decrease pollutant emissions.

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Conclusion