Enhancement of corrosion resistance and mechanical properties of API 5L X60 steel by heat treatments in different environments

Abstract

Steel pipelines are commonly used in the petroleum industry where high strength and durability values are required. In oil installations, the problems of corrosion, especially with crude oil, appear clearly and dramatically, in dealing with API 5L series. Improving the corrosion protection and mechanical properties are a genius goal for steel manufacturers, the heat treatment processes are familiar with this field. In this study, experimental investigations were executed to find the heat treatment influence on the corrosion rate, microstructure, and mechanical properties behavior of API 5L X60 pipeline steel in the presence of three different environments: seawater, freshwater, and crude oil. Two austenitizing temperatures 900°C and 800°C were prepared followed by quenching at 600°C, 450°C, and 300°C respectively, where the corrosion rate was estimated by the mean weight loss method. In this study, more than 60% of the corrosion rate in both seawater and freshwater was improved at 900 ºC austenitizing tempered at 300ºC for the selected pipeline specimens while only 22% reduction was achieved in crude oil. Different microstructure phases appeared in the heat-treated specimens such as tempered martensitic at 300°C and fine-grained ferrite with polygonal ferrite at 600°C. The microhardness values decreased with increasing the tempering temperatures while impact toughness values increased with tempering temperature increasing from 300°C until it was reached 450°C and then return to decrease again in 600°C.

Optimal Profile for a Fin of Constant Cross Section With Modelation of the Thermophysical Properties

“…Thus, the differential equation for the temperature distribution in dimensionless form (corresponding to a constant cross section fin), in terms of the Biot number, is given by (Lieth et al, 2021):…”

Effects of immersion in the NaCl and H2SO4 solutions on the corrosion rate, microstructure, and hardness of stainless steel 316L

“…Firstly, 100 mL of NaCl and H2SO4 solutions with the same molar concentration (0.017 M) were prepared in a different compartment. After that, a rectangular shape of SS 316L was prepared with a dimension of 20 mm x 10 mm x 2 mm and hanged with a inert rope [38,39]. Fig.…”

“…Lieth et al investigated effects of heat treatment on different water condition i.e., sea water, fresh water, and crude oil by immersion method. They found that the severe corrosion occurred in the sea water at high temperature [21]. Another study by Ji et al found that the higher the concentration of the mixed solution and the higher the test temperature, the greater the corrosion rate of 316L stainless steel wire and the lower the breaking strength of 316L stainless steel wire [22].…”

Sustainable and Green Approach for Api 5L Pipeline Steel Acidic Corrosion Inhibition Using Agro-Industrial Waste: Experimental and Theoretical

“…These activities lead to the metal degrading. Corrosion leads to a decrease in the steel's mechanical properties, causing a reduction in thickness, strength, and tenacity, as well as material degradation [2], thereby resulting in an approximately 80-90% failure in this sector. However, methods for controlling or improving such an occurrence has become a research focus.…”