Hydrogen Sulfide Corrosion Cracking Research Articles

Study of corrosion-resistant steels in hydrogen sulfide-containing environments of oil and gas fields

Hydrogen sulfide corrosion cracking of steel occurs in deposits containing corrosive components - hydrogen sulfide and carbon dioxide (carbon dioxide). The mechanism of corrosion cracking of steel in hydrogen sulfide-containing environments of corrosive oil and gas fields is considered, and factors influencing hydrogen sulfide cracking are identified. Increasing the performance properties of carbon, low-alloy, structural steels resistant to hydrogen sulfide and sulfide cracking was carried out on the basis of improving the composition of the components of chemical elements and the structural state through the choice of heat treatment methods depending on the acidity and temperature of the environment, partial pressures of carbon dioxide and hydrogen sulfide. Laboratory and production tests have shown the durability of the proposed compositions chemical elements of steels to hydrogen sulfide cracking, sulfide cracking and hydrogen swelling in deposits containing corrosive components was 70–80% compared to existing carbon structural steels.

Influence of the Structure of Carbon Steels on the Corrosion, Hydrogenation, and Corrosion Cracking in Hydrogen-Sulfide Media

We study the influence of the structure of carbon steels on corrosion, hydrogenation, and corrosion cracking in NACE solution. The corrosion and hydrogenation rates of U8 steel increase with the range of particle sizes in the structure in the following order: pearlite, sorbite (high-temperature martensite), troostite (medium-temperature martensite), and martensite. In 45 steel, these rates are maximum for the ferrite-pearlite structure and minimum for sorbite. The 45 steel is less susceptible to hydrogen-sulfide corrosion cracking in a NACE solution than U8 steel, which reveals the dependence on the content of carbon and, hence, on the content of carbides. The 45 steel with sorbite structure and U8 steel with sorbite and troostite structures are characterized by the highest resistance to fracture in hydrogen-sulfide media. However, in view of the influence of hydrogenation, steels with sorbite structures prove to be most suitable for operation in hydrogen-sulfide-containing media.

Protective Properties of Aluminum-Based Coatings in Hydrogen-Sulfide Media

We study the corrosion and corrosion-mechanical properties of 20 steel with electric-arc sprayed aluminum coatings in chloride- and hydrogen-sulfide-containing media. The elevated corrosion resistance of the coatings is observed in all testing media. It is shown that hydrogen sulfide has practically no effect on the corrosion rate of the coating. The high resistance to hydrogen-sulfide corrosion cracking (HSCC) of 20 steel with aluminum and combined (thermally sprayed aluminum + polyurethane Hardtop flexy) coatings is established. Under the conditions of slow tension of the specimens with aluminum coatings in NACE solutions, the stresses corresponding to the onset of damage of the coating (with its subsequent final failure) are determined.

Influence of defects of welded joints of 17G1SU pipe steel on its resistance to hydrogen-sulfide cracking

We have studied the influence of defects in welded joints of 17G1SU pipe steel performed by manual electric arc method with UONII 13/55R, FOX EV 50 (Bohler), and Basic One (Lincoln) electrodes on the serviceability of welded structures in air and environments containing hydrogen sulfide. We have established that bulk defects, having a total area of up to 15% of the calculated cross section of a welded joint performed with UONII 13/55R electrode, do not affect its strength under slow deformation (10−5 sec−1). Defects reduce significantly the resistance of welded joints to hydrogen-sulfide corrosion cracking: in the presence of comparable defects, the threshold stresses of specimens welded with UONII 13/55R and FOX EV 50 electrodes are 60 MPa lower than for specimens without defects.

Problems of fracture of metals in hydrogen-sulfide media

We consider the principal types of fracture of steels in hydrogen-sulfide media and the methods used for their investigation. The analysis of the available literature on hydrogen-sulfide corrosion cracking of low-alloy structural steels shows that, in order to guarantee their high fracture resistance, it is necessary to decrease the sulfur content of these steels to 0.002–0.005%. The procedure of alloying of steels with rare-earth metals, as a result of which nonmetallic inclusions take globular shape and sulfur is bound in thermodynamically stable sulfides, also gives a positive effect. It is demonstrated that the ferritic-austenitic and chromium-nickel-molybdenum austenitic steels exhibit the highest resistance to hydrogen-sulfide cracking among stainless steels. It is also established that, under asymmetric stresses, the high resistance of steels to hydrogen-sulfide stress-corrosion cracking does not guarantee their high corrosionfatigue strength and, in this case, the influence of the amplitude of stresses is stronger than the influence of the mean value. The directions of subsequent investigations of the influence of hydrogen-sulfide and chloride media on the serviceability of metals are outlined.

The corrosion of welded joints of 16GS + 08Kh13 bimetal, made of the specimens cut out from a column after the long-term operation

Corrosion-electrochemical investigations into bimetals are conventionally carried out on samples with the carrying layer preliminarily removed. In this work, the liability of welded joints to HSC without removal of the carrying layer is investigated, which has considerably enhanced the information content of the results. A possibility is demonstrated of the application of ANV-70B electrodes and Sv-07Kh25N13 welding wire, developed at the Paton Electric Welding Institute, in the process of welding in an Ar + O2 gas mixture for repairing equipment manufactured from bimetal equipped with a cladding layer of 08Kh13 steel. It is established that the preliminary heating of the bimetal up to 350°C in the welding process with the application of both ANV-70B electrodes and Sv-07Kh25N13 welding wire enhances the resistance of the metal to hydrogen sulfide corrosion cracking.

INFLUENCE OF HYDROGEN SULFIDE ON SERVICEABILITY OF MATERIALS OF GAS FIELD EQUIPMENT

We analyze basic types of corrosion, corrosion-hydrogen, and corrosion-mechanical fractures of steels in hydrogen sulfide-containing media. We propose a new concept based on the chemical interaction of atomic hydrogen with thermodynamically unstable inclusions and carbides of steel, which results in the formation of microvoids on “metal–inclusion” boundaries. This is the main reason for hydrogen sulfide corrosion cracking and hydrogen-induced cracking of steels.

Effect of structure and strength on the corrosion resistance of corrosion-resistant steels and alloys in media containing hydrogen sulfide and chlorine ions

Equipment in gas and oil wells comes in contact with media, whose aggressiveness is determined by the chlorine-ion content, the partial pressure of hydrogen sulfide and carbon dioxide gas, and temperature. Hydrogen sulfide corrosion cracking (HSCC), pitting, and general corrosion are basic forms of corrosion failure in these inedia. In a number of cases, special structural steels, whose corrosion resistance can be enhanced with inhibition of the medium, are used in fabricating the equipment. Corrosion-resistant steels should be employed when inhibition is inapplicable, and, in addition to HSCC, the development of pitting and general corrosion is possible during service. The resistance of austenitic, austenitic -ferritic, and rnartensitic steels to HSCC and pitting are investigated in this paper.

Effects of steel composition and production technology on hydrogen-induced cracking sensitivity and hydrogen sulfide corrosion cracking: Survey of foreign research

Low-carbon microalloyed steels containing niobium, vanadium, molybdenum, and copper can be made with low levels of sulfur, phosphorus, and oxygen and with optimum shapes for the nonmetallic inclusions to give high resistance to hydrogeninduced cracking and sulfide stress corrosion cracking.

Role of the high pressure of hydrogen in the phenomenon of hydrogen sulfide corrosion cracking of steel

Role of the high pressure of hydrogen in the phenomenon of hydrogen sulfide corrosion cracking of steel

Study of the integrity of pump rod in media containing hydrogen sulfide

Studies were carried out on the resistance of the rod steels to failure by corrosion, hydrogen-sulfide corrosion cracking, and fatigue in media containing hydrogen sulfide, and also on the effectiveness of the methods of increasing it. Corrosion-fatigue curves for the steels studied are shown. It was found that an effective method of safeguarding the material of pump rods from corrosion-fatigue failure is shotblasting followed by the application of a metal-polymer coating.