Analysis of the causes of failure in 5Cr-1Mo pipes mounted in a preheating furnace

Abstract

The oxidation resistance of iron-based alloys depends on the formation of thin protective films consisting of reaction products between the alloys and the ambient atmosphere. The high corrosion resistance of Fe-Cr-Mo alloys has been attributed to the rapid formation of a uniform, highly protective passive film. The pipes hardness and resistance to various forms of corrosion are determined by the composition of the oxide layer that plays an important role in determining the lifetime of the pipes themselves. The thermal stability of the oxide layer is influenced by its composition and thickness as well as by the bond to the underlying metal. Determining factors for the high temperature corrosion are generally: temperature, metallurgy, TAN (chloridric and naphthenic acid), local flow conditions, sulphur compounds.

Numerical study of semi-elliptical cracks in the critical position of pipe elbow

“…This situation may affect the energy transport significantly and increase the possibility of corrosion to occur. Many authors have studied the interaction between fluid and solid or solid-solid for two types of damage such as erosion and corrosion of steel pipelines [12][13][14][15]. El-Gammal et al [16] have presented the flow accelerated corrosion of a 90-degree elbow by computational fluid dynamics (CFD) simulation.…”

Electrochemical Analysis of Temperature, Concentration and Velocity Effects in Naphthenic Acid Corrosion of 5%Cr-1%Mo Steel

“…To reduce the impact of these operational factors, atmospheric furnaces are usually made with austenitic stainless steel enhanced with molybdenum and chromium. The Mo-Cr steel combine, creep resistance, strength and toughness that can be achieved through tempering and high corrosion resistance (3,(7)(8)(9). Particular purpose of this work was known the electrochemical effects that temperature, acid concentration and velocity of flow have in naphthenic acid corrosion mechanism.…”