Cr Stainless Steel Research Articles

Influence of oxygen partial pressure on the passivation and depassivation of super 13Cr stainless steel in high temperature and CO2 rich environment.

The passivation and depassivation characteristics of Super 13Cr stainless steel were examined under a range of oxygen partial pressures within a high-temperature (120 ℃) and high-pressure (3MPa) CO2 atmosphere. We performed comprehensive electrochemical assessments, encompassing open-circuit potential monitoring, electrochemical impedance spectroscopy, and linear polarization resistance analysis, to evaluate the corrosion resistance and passive film stability. The results demonstrate that the addition of low O2 partial pressures enhanced the stability of the passive film, while higher O2 levels led to the loss of the passivation properties of Super 13Cr stainless steel. The study elucidates the pivotal role of oxygen in the corrosion mechanisms affecting Super 13Cr stainless steel, presenting valuable data to enhance for integrity management in severe environmental conditions.

Optimizing the surface quality of heat-treated 2Cr13 stainless steel via electrochemical machining

The improvement of mechanical properties and surface quality was of great significance for materials. In this study, 2Cr13 stainless steel was subjected to the quenching and tempering treatment. The electrochemical machining approach was adopted for surface treatment. The results showed that the quenching and tempering treatment improved the Vickers microhardness of 2Cr13 stainless steel. The enhancement of microhardness was facilitated by the formation of tempered sorbite and grain refinement. Electrochemical machining provided high quality surfaces. The heat-treated workpice had more advantages in electrochemical machining efficiency. The polarization curves proved a downward shift of the self-corrosion potential for the heat-treated 2Cr13 stainless steel, which was strongly related to the electrochemical behavior. A mechanism model for promoting anode electrochemical dissolution was proposed.

A NOVEL MODEL FOR THE RELATIONSHIP BETWEEN THE HEALING TIME OF THE INERT FILM AND THE INCUBATION PERIOD OF LOCALIZED CORROSION

A model for the relationship between the healing time of the scratched diamond-like carbon (DLC) film and the localized corrosion incubation period of metal was established. Based on model calculations combined with experimental results, the scratched DLC film on 13Cr stainless steel was able to heal within 10–16[Formula: see text]h in NaCl solution with an adsorbent-type corrosion inhibitor. However, the localized corrosion incubation time was 30–40[Formula: see text]h. Healing of the scratched DLC film can be completed before localized corrosion occurs. This model provides a theoretical reference for the scratch-repassivation of inert films in corrosion inhibitors solutions.

Effect of ultrasonic vibration-assisted laser cladding frequency on the microstructure and properties of Fe-0.5C-15Cr alloy cladding layers

In this paper, Fe-0.5C-15Cr wear and corrosion resistant alloy coating was prepared on 3Cr13 stainless steel surface by ultrasonic vibration assisted laser cladding technology. The effects of ultrasonic vibration frequency on the microstructure, microhardness and corrosion resistance of the coating were studied. The results show that the length of the dendrites of the cladding layer decreased significantly after ultrasonic vibration is applied, the grains size is refined significantly, and the morphology of the grain boundary carbides changed from fishbone-like to short rods, when the vibration frequency is 20.2 kHz, the grain refinement is the most significant, and the orientation of the dendrites is obviously weakened. The hardness of the applied ultrasonic vibration specimens increased by 10–20 HV0.2 relative to the non-ultrasonic specimens, with the increase of vibration frequency, the hardness of the cladding layer firstly increased and then slightly decreased, and the peak appeared at 20.2 kHz. The coefficient of friction of the specimens when the ultrasonic frequency of 20.2 kHz is applied is lower than that of the specimens with non-ultrasonic frequency by 12.8 %, and the abrasive wear rate is reduced by 14.3 %. After ultrasonic vibration, the pitting potential of the cladding layer increases, the dimensional passivation current density decreased, the width of the passivation zone becomes wider, and the intergranular corrosion reactivation rate decreased, When the ultrasonic frequency is 20.2 kHz and 20.4 kHz, the pitting corrosion resistance and intergranular corrosion resistance of the cladding layer are significantly improved. This is because the cavitation effect, resonance effect and acoustic flow effect of ultrasonic vibration promote the non-uniform nucleation, refine the dendrites and intergranular carbides, and promote the redistribution of the corrosion-resistant element Cr in the in-grain martensite and grain boundary carbides, increasing the content of Cr in the matrix, and thus improving the wear resistance and corrosion resistance of the cladding layer.

Impact of stainless steel nano-alloys on biogas production rate: safe catalysts

The feasibility of using nontoxic stainless steel colloidal solutions, synthesized by laser ablation in distilled water, for the production of biogas is examined in this paper. Given that their biodigesters are treated concurrently while taking into account the same experimental and environmental circumstances, certain results are compared with earlier work on NiFe2O4. As a result, the cumulative gas volume after the 50-days incubation period increased to 172 and 207% for NiFe2O4 and stainless steel nano-alloys, respectively. Additionally, the biogas flame and the information at hand are used to interpret the biological effect. The free Cr stainless steel colloidal solution yields an unexpected biogas volume of 207% of control, according to a recent discovery. However, the inhibition of Cr-based stainless steel digesters is attributed to the heat shock mechanism–based NIR resonance fluorescence property.Novelty statementEnhancement of biogas production rate from cow dung by 207%, in comparison to control, using nontoxic stainless steel nano-alloys free of Cr element synthesized by laser ablation of commercial targets in water. However, nano-alloys based on Cr element exhibit an inhibition effect due to a heat shock mechanism. Accordingly, stainless steel nano-alloys synthesized by laser ablation in water are eco-friendly and safe catalysts for applicants and users.Graphical abstract

Bridge for the thermodynamics and kinetics of electrochemical corrosion: Designing a corrosion–resistant HP–13Cr stainless steel by Cu alloying for use in an H2S–containing geothermal environment

The dissolution–ionization–diffusion–deposition (DIDD) model was used for developing a corrosion–resistant stainless steel (SS) by the means of alloying and the guidelines for the process were proposed. The novel HP–13Cr–Cu SS was designed to resist corrosion in H2S–containing geothermal environment. The results indicated that the preferential deposition of CuS promoted the heterogeneous nucleation rate of Cr2O3, FeCr2O3, and FeS, which formed denser corrosion product layer. As a result, this alloy exhibited a low corrosion rate and a high sulfide stress cracking (SSC) resistance. The results were consistent with the theoretical calculation conducted by the DIDD model.

Pit initiation mechanism of modified martensitic 13Cr stainless steel exposed to CO2 saturated acidic environments at elevated temperatures induced by Ti(C,N) inclusions

The influence of temperature (25, 75, and 150 °C) on the passivation behavior of Modified Martensitic 13Cr Stainless Steel (M13Cr) in CO2 saturated acidic salt brine environments was investigated. The material was found to contain Ti(C,N) inclusions and Volta potential maps obtained through scanning Kelvin probe force microscopy (SKPFM) identified them to be more anodic (60 mV lower) than the matrix. Cyclic polarization (CP) showed a shift in pitting and repassivation potentials to more negative values at higher temperatures. Electrochemical impedance spectroscopy (EIS) and Mott–Schottky tests showed that the passive film formed was more defective with increasing temperature. X-ray photoelectron spectroscopy (XPS) confirmed the presence of a defective passive film with reduced repassivation capabilities due to higher contents of soluble CrO3/Cr6+ species at temperatures exceeding 75 °C. These results offer valuable insights into understanding the pit initiation mechanisms and performance of M13Cr.

Using the Radial Shear Rolling Method for Fast and Deep Processing Technology of a Steel Ingot Cast Structure.

In advancing special materials, seamless integration into existing production chains is paramount. Beyond creating improved alloy compositions, precision in processing methods is crucial to preserve desired properties without drawbacks. The synergy between alloy formulation and processing techniques is pivotal for maximizing the benefits of innovative materials. By focusing on advanced deep processing technology for small ingots of modified 12% Cr stainless steel, this paper delves into the transformation of cast ingot steel structures using radial shear rolling (RSR) processing. Through a series of nine passes, rolling ingots from a 32 mm to a 13 mm diameter with a total elongation factor of 6.02, a notable shift occurred. This single-operation process effectuated a substantial change in sample structure, transitioning from a coarse-grained cast structure (0.5-1.5 mm) to an equiaxed fine-grained structure with peripheral grain sizes of 1-4 μm and an elongated rolling texture in the axial part of the bar. The complete transformation of the initial cast dendritic structure validates the implementation of the RSR method for the deep processing of ingots.

Mechanically enhancing a brazed joint of WC-Co/3Cr13 by utilizing a nanoporous Cu lamina interlayer prepared by chemical dealloying

Ag-Cu-Ti brazing alloys may allow sound joining between WC-Co cemented carbide (YG20) and 3Cr13 stainless steel. However, the issue of excessive formation of agglomerated brittle Cu-Ti compounds in the joint seam, which deteriorates mechanical performance, is still a major processing drawback. Here, a nanoporous copper (NP-Cu) lamina, prepared by chemically dealloying an Mg67Cu33 (at. %) alloy precursor, was used as an interlayer for assisting the brazing process between YG20 alloy and 3Cr13 stainless steel. The effect of introducing the NP-Cu interlayer on the microstructure and mechanical properties of the joints was investigated. Results revealed that the Cu-Ti compounds in the brazing seam acquired reduced size and dispersed distribution by applying the NP-Cu interlayer. The technique outperforms the directly brazed alternative, with a shear strength increase of 70%. The interlayer contributed by its high specific surface and excellent surface metallurgical activity, overcoming the drawback of agglomerated Cu-Ti compound development. The new technique allows a process based microstructural and chemical control, with vast potential applications in the joining of WC-Co cemented carbide and stainless-steel materials.

Enhanced scale inhibition and anti-wax capacities of passive materials via ultrasonic rolling processing

Scale damage and wax formation on pipelines surface have become prevalent issues in the development and production of the oil and gas industry throughout the world. The utilization of the ultrasonic surface rolling process (USRP) on pipeline surfaces is a promising protective approach and its universal verification for the enhancement of the scale inhibition and anti-wax capacities of passive materials is presented in this work. The effect of USRP on surface integrity (including roughness, cross-sectional microstructure, residual stress and water contact angle), scaling and wax deposition behavior, passive film structure and characteristics are experimentally analyzed by comparing three passive materials (13Cr stainless steel, 825 nickel-base alloy and Ti6Al4V alloy) with 3Cr carbon steel. The results indicate that USRP can effectively reduce the surface roughness and contribute to the growth of passive film due to the enriched passive elements on the metal surface, which consequently endow the passive materials with reduced surface free energy and enhanced anti-scaling/anti-wax capacities. Furthermore, benefitting from the surface passivation, the enhancement in the corrosion resistance of the film helps to provide good chemical stability. The main reason for why USRP has a protective effect on the scale inhibition and anti-wax capacities of the passive materials is also elucidated. The input energy of USRP not only achieves chip-free polishing and triggers structural response changes in the surface and subsurface plastic deformation but also produces a unique passivation response that can alter the chemical composition, thickness, compactness and defect density of the passive film. This in turn leads to significant changes in its corrosion resistance, which is related to the semiconductor characteristics of the materials, surface energy, and hydrophilic–hydrophobic physical and chemical properties. This results in a significant inhibitory effect on the deposition of scaling ions or wax crystals at the passive film/solution interface.

New insight into the fitness of 13Cr stainless steel in H2S-containing environment at high temperature

In the oil and gas industry, the selection of tubing and casing materials is required to follow international standard ISO 15156. However, it does not provide guidance on selecting stainless steel materials for H2S-containing wells above 232 °C, which raises uncertainty about the suitability of 13Cr steel. This work focuses on investigating the mechanical degradation and failure mechanisms of 13Cr stainless steel exposed to high-temperature conditions and proposed a creep constitutive model. Then, the corrosion and cracking mechanisms of 13Cr stainless steel at temperatures ranging from 150 °C to 350 °C were elucidated. Results show that 13Cr stainless steel meets the current material selection criteria (GB/T34907-2017) for mechanical properties and creep resistance. In the range of 150–250 °C, the localized corrosion is dominant, and stress-oriented hydrogen-induced cracking occurs at 150 °C. As the temperature increases from 250 °C to 350 °C, although the maximum value of uniform corrosion rate is as high as 0.2960 mm/a, the cracking does not happen. Therefore, with the implementation of suitable protective measures, 13Cr stainless steel can be utilized in wells that the temperatures ranging from 250 °C to 350 °C and H2S partial pressures up to 0.17 MPa. This aligns with the global carbon-neutral agenda.

A high corrosion resistant Fe-VC layer laser cladded under water-cooled substrate condition

Nano VC reinforced submicron Fe-based composite cladding layers were successfully obtained under water-cooled substrate conditions, showing an absence of noticeable defects. The matrix of the layer mainly consisted of equiaxed grains, with the average grain size refined to 0.78 μm. The VC with an average particle size of 72 nm distributed along the grain boundaries. As a result, the hardness of the layer increased from 225 HV0.2 to 930 HV0.2. Additionally, the cladding layer exhibited prominent passivation characteristics, its corrosion resistance was comparable to that of the 2Cr13 stainless steel.

Fatigue crack initiation and growth of laser shock peened 2Cr13 martensitic stainless steel as a function of the coverage layer

Fatigue properties and plastic deformation-induced gradient nanostructures of 2Cr13 martensitic stainless steel subjected to laser shock peening (LSP) were investigated. Combining the residual stresses and microstructural evolution of 2Cr13 martensitic stainless steel before and after three-point bending fatigue test, the influences of LSP on fatigue crack initiation and growth are systematically analyzed. Results showed that massive LSP treatments with one and two coverage layers caused obvious improvements of 13% and 37.6% in the fatigue crack initiation life, 19.3% and 34.9% in the fatigue lives of 2Cr13 stainless steel, respectively. Typical in-depth microstructures for two kinds of LSP-treated specimens were described by transmission electron microscopy characterization. Results showed that dynamic recrystallization (DRX) process at room temperature may be activated and accelerated by LSP-induced atom collision, and then a nucleation equation by ultrahigh-strain-rate plastic deformation was developed, which depended strongly on LSP-induced ultrahigh strain rate. Moreover, the basic improvement mechanism of LSP on fatigue properties was analyzed in detail.

Effects of ferrite content and concentrations of carbon and silicon on weld solidification cracking susceptibility of stainless steels

In the welding of austenitic stainless steels, the formation of approximately 5% δ-ferrite phase is often used to decrease the susceptibility to solidification cracking. The partition coefficients of impurity elements such as phosphorous and sulfur of the ferrite phase are high, which expand the temperature range of solidification. At the same time, it is well known that the solidification cracking susceptibility increases with increasing δ-ferrite content above 20%. Thus, high δ-ferrite content increases the solidification cracking susceptibility, even though the δ-ferrite phase has high solubility of the impurity elements. The aim of this work was to investigate the effects of the δ-ferrite content and the concentration of carbon and silicon on the solidification crack susceptibility of Fe–18%Cr stainless steel with various nickel concentrations. The ferrite content was controlled by adding various amounts of nickel. The brittle temperature range (BTR) hardly changed with increasing δ-ferrite content, regardless of the type and concentrations of carbon and silicon. Therefore, the effect of the ferrite content on solidification cracking susceptibility must be small. In addition, the BTR increased with the concentrations of carbon and silicon. The specimens containing higher concentrations of carbon exhibited higher BTRs than those containing silicon. It is considered that the solidification segregation corresponding to the partition coefficient of carbon to the δ-ferrite phase induces an increase in cracking susceptibility. In addition, the formation of austenite during solidification reduces cracking susceptibility owing to the higher solubility of carbon.

Microstructure and Mechanical Properties of a Multiphase 17%Cr Stainless Steel

Microstructure and Mechanical Properties of a Multiphase 17%Cr Stainless Steel

A Three-stage Hybrid Multi-criteria Model for the Selection of Material for Subsea Pipeline Design Considering Several Environmental Scenario.

Subsea pipelines are such a crucial part of offshore oil and gas production, therefore their design and construction should be as efficient and cost effective as possible. Proper material selection is critical for a successful operation and a longer pipeline lifespan. For the selection of a design material with the highest reliability under dynamic environment as the one obtained in the oil and gas industry, a three-stage hybrid multi-criteria model have been proposed. The hybrid multi-criteria model, which is based on an integrated Analytical Hierarchy Process (AHP) model and the VlseKriterijumskaOptimizacija I KompromisnoResenje (VIKOR) model, is used for the evaluation and selection of a suitable and high reliability-based design material for the subsea pipeline design by considering several operational and environmental scenario the pipes might encounter in the field. With the vast amount of engineering materials available to the design engineer, selecting a suitable and high reliability-based material for the subsea pipeline design is a tedious and demanding task especially under a dynamic environment scenario. In this paper, ten subsea pipeline material alternatives of different types, with seven criteria, have been critically examined under a three case scenario. Results from the evaluation show that, for the first case study scenario -sour service hydrocarbon transport in deep waters-, 22% Cr stainless steel is found to be the best choice material, for the second case study scenario, Carbon Fiber Reinforced Polymer is selected as the best. While for the third case study scenario, carbons steel and polymers material is found to be the most reliable material choice.

Notch sensitivity and short cracks tolerance in a super 13Cr stainless steel under sulfide stress corrosion cracking conditions

Abstract Notch sensitivity under sulfide stress corrosion cracking (SSC) conditions is quantified in this work, considering its tolerance to short cracks that start at notch tips and become non-propagating after growing for a short while. The considered material is an UNS S41426 super 13Cr5Ni2Mo martensitic stainless steel, frequently used in pipelines to transport aggressive fluids in offshore applications. Tolerance to short SCC cracks depends on the notch size and shape, on the stress gradient ahead of its tip, and on basic material resistances to crack initiation S SSC and growth K ISSC inside the aggressive environment. The proposed notch-sensitivity model can be a powerful and economical alternative design tool to substitute traditional pass/non-pass criteria normally used to choose materials for SSC and similar environmentally assisted cracking (EAC) service conditions. This model is validated by testing the steel into an aqueous solution of 100 g/L of Cl−, pH 4.0, 25 kPa of H2S, and 75 kPa of CO2, at 23 ± 2 °C. After measuring S SSC (461 ± 23 MPa) and K ISSC (36.9 ± 0.6 MPa√m), short crack tolerance predictions are verified on notched specimens loaded under a peak stress at their tips σ max = 0.95⋅S Y >> S SSC, where S Y = 826 MPa is the yield strength of the tested steel.

Effect of Chloride and Iodide on the Corrosion Behavior of 13Cr Stainless Steel

The corrosion behavior and mechanism of 13Cr stainless steel in the solution with 1 mol/L NaCl and 5 mmol/L KI were investigated by weight loss method, scanning electrochemical microscopy (SECM), the phase analysis (XRD) of inclusions, and surface analysis technique (SEM and EDS). Results showed that the corrosion rate was a linear relationship with the time and Cl− concentration. The corrosion became serious with the increase in time and Cl− concentration. The corrosion occurred in the unstable electroactive points that contained aluminum oxide and metallic phase inclusions. The generation and disappearance of the electroactive points simultaneously occurred with the corrosion. The active dissolved level on different areas of the surface of 13Cr stainless-steel sample was different. The oxidation current peak of the sample presented the strip shape. The corrosion dissolution was mainly caused by aluminum oxide inclusions (Al2O3) and FeAl phase.

Evaluating the effects of environmental aging on the pitting corrosion of steam turbine blade steels

AbstractA flow loop has been setup to allow simulation of operating conditions in a steam turbine during transitions in water chemistry between on‐load (deaerated) and off‐load (aerated) environments. Electrochemical noise measurements were performed to establish the critical chloride concentration for pitting of 403 12Cr stainless steel. The results were confirmed by comparative measurements of corrosion potential and visual observation of pitting. X‐ray photoelectron spectroscopy was used to quantify changes in the passive film due to transient environmental conditions. The critical chloride concentration for pitting with/without pre‐exposure to on‐load conditions has been measured and the impact of environmental aging is discussed.

Deposition of an adherent diamond film on stainless steel using Cr/Cr[sbnd]Al[sbnd]N as an interlayer

Cr/CrAlN films were chosen as an interlayer to deposit an adherent diamond film on stainless steels by using hot filament chemical vapor deposition (HFCVD). The results show that diamond film with good adhesion is successfully deposited on 3Cr13 stainless steel when the interlayer with Al content from 0 to 18 at.%, which is ascribed to high chemical adhesion by a certain amount of chromium carbide. When Al content in the interlayer further increases, an excessive Al2O3 is formed on the surface of the interlayer, carbon supersaturation is easily arrived, so that the amount of the carbide at the diamond/interlayer interface decreases evidently. This decreases the strength of the covalent bonding from the carbide, producing poor adhesion. Moreover, with the raise of Al content in the interlayer, the hardness of the multilayer coated stainless steel increases due to the increase of the interlayer's hardness and the slight increase of the diamond content in the film.