Stainless Steel-carbon Steel Research Articles

Failure Mechanisms in Stainless Steel/Carbon Steel Clad Plate Under Shear Tensile Loading: Experimental and Modeling Methods

The deformation behavior of a stainless steel/carbon steel (SS/CS) clad plate under interface shear loading is characterized in this work. A 2D digital image correlation method is applied to track the strain field variation near the interface during shear tensile tests. Then, a cohesive zone model (CZM) finite‐element method is developed to clarify the delamination behavior of the tested clad plate. Finally, the interfacial failure characteristics of the SS/CS clad plate are further presented through the comparison between the finite‐element method and fractography analysis at the interface. In the experimental and simulation results, it is shown that the mixed‐mode CZM, which couples the constitutive equations of three fracture modes, demonstrates excellent capabilities in capturing SS/CS interfacial deformation behavior. The main deformation mode in shear tensile tests is variable according to locations. The central region at the bonded surface is dominated by the shear delamination mode, and the region near the notches shows shifted crack propagation toward normal mode. These abrupt interfacial failures can be clarified via stress state and local damage analysis of the well‐reproduced finite‐element model of cladding material.

Microstructural study of additively-manufactured carbon steel-stainless steel 316L - Inconel 625 functionally graded material: Simulation and experimental approaches

This study aims to analyze the microstructure and present phases of functionally graded carbon steel - stainless steel 316L - Inconel 625 using experimental methods and computational software (JMatPro). Both FE-SEM and SEM-EDS equipment were employed to evaluate the materials. The JMatPro software accurately simulated the present phases and their formation temperatures. The microstructure in the plain carbon steel part formed the ferrite phase at 900 °C, while a small amount of pearlite structure formed at 700 °C, remaining stable at ambient temperature. Chromium phase in stainless steel 316 L layers increased with solidification, with a higher increase in the delta ferrite phase. Inconel 625 at 1130 °C, the Laves nucleated with austenite, stable up to ambient temperature. As liquid decreased, niobium and molybdenum accumulation increased, potentially leading to Laves formation. The significant increase in niobium content at the interface of stainless steel 316L-Inconel 625 is attributed to an increase in iron content. The research indicated a good correlation between the observed and predicted microstructures.

Experimental study and simulation of the interface shear deformation behavior in AISI304/Q235 clad plate with thin cladding layer

The mechanical properties and interface damage characteristics of hot-rolled bonded stainless steel/carbon steel (SS/CS) clad plate with thin cladding were investigated. The focus is on mechanical property-microstructure relationships in shear deformation. In detail, the mechanical response of the cladding components and clad plate were characterized. Then a hybrid numerical–experimental identification procedure for the cohesive zone model (CZM) in the simulation of heterogeneous SS/CS interface using finite element (FE) method was developed. A mixed-mode bilinear CZM, considering the anisotropy of the thin cladding was coupled FE model, showing a high accuracy for predicting the shear deformation behavior. The results showed obvious differences in the microstructure and mechanical properties of the SS and CS layers and the formation of an inhomogeneous interfacial layer. Additionally, the bond strength and delamination position of SS/CS clad plate are highly dependent on the interfacial oxide distribution and elemental diffusion behavior. Interestingly, the thin cladding is subjected to bending moments in shear deformation, resulting in delamination of the interface that is not completely dominated by one shear mode. And these abrupt interfacial failures could be clarified via stress-strain state and local damage analysis of the well-reproduced FE model of cladding material.

Galvanic Corrosion of Mill-Scaled Carbon Steel Coupled to AISI 304 Stainless Steel in the Chloride-Contaminated Mortars

In order to assess the durability of concrete structures reinforced by different types of steel in aggressive environments, the galvanic corrosion of mill-scaled carbon steel was investigated when it was connected to AISI 304 stainless steel characterized by various cathode/anode surface area ratios (As:Ac) in chloride-contaminated mortars. The galvanic potential and the galvanic current density of the coupling carbon steel were measured, and the corrosion state of the mill-scaled carbon steel was inspected after 1,450 days. The results indicated that the potential of the carbon steel was slightly positively shifted by the stainless steel. High As:Ac ratios promoted the passivation of the coupling carbon steel and lowered the corrosion current density in the chloride-contaminated mortars. The galvanic current densities of the carbon steel-stainless steel couples increased with As:Ac ratio. Because the corrosion current density of the mill-scaled carbon steel was nearly one order of magnitude higher than the galvanic current density, the total corrosion current density of the coupling mill-scaled carbon steel generally decreased, and its overall corrosion diminished with increasing As:Ac ratio. Finally, based on the results of this study, the As:Ac ratio is recommended to be higher than 2:1 to ensure the sufficient durability of submerged concrete structures in an aggressive concrete environment.

Simultaneously enhanced strength-ductility synergy and corrosion resistance in liquid-solid bonded stainless steel cladding carbon steel plate by hot rolling and annealing treatment

Liquid-solid (L-S) bonded stainless steel/carbon steel (SS/CS) laminated composites have strong metallurgical bonding interface, while the solidification structure of SS deteriorates the mechanical properties and corrosion resistance. In this study, hot rolling and annealing were proposed to regulate the microstructures and balance the performance of L-S bonded SS/CS clad plates. SS cladding CS plates were prepared by horizontal continuous liquid-solid composite casting and hot rolled at 1200 °C with a reduction rate of 90%, and annealed at 1000 and 1050 °C for 30 min. The microstructural evolution was studied by scanning electron microscope and electron back-scatter diffraction, elemental distribution was investigated by electron probe microanalysis. Microhardness, tensile test and anodic-cathodic polarization test in a 3.5% NaCl solution were carried out on hot-rolled and annealed SS cladding CS plates, and the mechanism for the simultaneous enhancement of strength-ductility synergy and corrosion resistance by hot rolling and annealing was analyzed. Annealing at 1050 °C resulted in excellent properties with tensile strength of 550 MPa and elongation of 50%, corrosion potential of −0.21 V and corrosion current density of 0.13 μA cm−2. The strength and ductility of the SS cladding CS plate were synergistically improved by a strong metallurgical bonding cladding interface, high frequency of low-Σ CSLs and refinement of grains in 304 SS. The low-Σ CSLs in 304 SS restricted the formation of carbides in the carburized layer and broke down the connectivity of random boundaries, improving the corrosion resistance.

Effects of cracks on chloride‐induced corrosion initiation and propagation of carbon and stainless steel rebar

AbstractCurrent durability design models for reinforced concrete structures in chloride‐contaminated environments do not consider the effects of cracks, which in practice are almost inevitable. Literature reports controversial results on corrosion propagation time of carbon steel (CS) in cracked concrete, while fewer information can be found on stainless steel (SS) rebar, which can be employed as additional protection strategy. In this experimental study, corrosion initiation and propagation of CS and SS rebar in uncracked and cracked concrete are presented. Prismatic specimens, reinforced with CS and 304L SS bars were subjected to a loading procedure to induce longitudinal micro‐cracks and exposed to a 3.5% NaCl solution for more than 2 years. Corrosion was monitored with electrochemical techniques and at the end of exposure corrosive attacks were observed. Results demonstrate the fundamental contribution of micro‐cracks in accelerating corrosion phenomena for CS, while SS is still in passive conditions also in cracked concrete.

Interfacial microstructure and strengthening mechanism of stainless steel/carbon steel laminated composite fabricated by liquid-solid bonding and hot rolling

Stainless steel/carbon steel (SS/CS) laminated composites were prepared by liquid-solid (L-S) bonding followed by hot rolling under different reduction rates, and the microstructure characteristics at the cladding interface zone and their influences on the interfacial bonding strength of the SS/CS laminated composites were analyzed. A metallurgical bonding interface was obtained by the L-S bonding method, and coarse equiaxed grains, decarburization layer and oxides formed at the cladding interface zone. During hot rolling, heterodeformation occurred in the SS/CS laminated composites, resulting in asynchronous dynamic recrystallization and the refinement of grains in both SS and CS. The thickness of the decarburization layer and elements diffusion distance obviously decreased after hot rolling, while the ratio of the diffusion distances of Cr and Ni elements to the width of the decarburization layer increased with increasing reduction rates. Additionally, the oxides at the cladding interface zone transformed into hybrid inclusions after hot rolling, and the maximum equivalent diameter and volume fraction of the inclusions decreased with increasing reduction rates. The interfacial shear strength of the L&R bonded SS/CS laminated composites increased with increasing reduction rates, and a maximum value of 400 MPa was obtained at a reduction rate of 75%, which is 34% higher than that of the L-S bonded SS/CS laminated composite due to the grain refinement, improved relative diffusion distance of Cr and Ni elements, reduced and refined inclusions at the cladding interface zone.

Mechanical behavior and interfacial damage of carbon steel-stainless steel corrosion resisted-alloy (CRA) cladded plate: Hybrid analysis based on experiment and finite element modeling

The deformation behavior of a hot roll-bonded stainless steel/carbon steel (STS/CS) clad plate is investigated by focusing on the mechanical properties-microstructure relationship along the plate thickness and clad interface. In detail, the mechanical responses of the STS/CS clad plate and its constituents are evaluated using uniaxial tension, interfacial debonding tests (in normal and shear modes), and various microstructure characterization techniques, which clarify the interfacial heterogeneity of the STS/CS clad plate. The results of experimental analysis present the validity for applying a hybrid numerical–experimental identification procedure for the cohesive zone model (CZM) in the simulation of heterogeneous STS/CS interface using finite element (FE) method. Especially, the mixed-mode bilinear CZM coupled with the inhomogeneously distributed elastic-plastic properties over thickness can be optimized to accurately predict the measured load-displacement curves and springback in the two debonding tests and the V-bending test. Finally, the interfacial failure characteristics of the STS/CS clad are further presented through the comparison between the FE method and fractography analysis at the clad interface. The combined experimental and numerical study reveal interesting aspects beyond commonly reported interfacial behavior. These include: (1) The failure along the STS/CS clad interface is controlled by both “material factors” such as the carbon migration from the interface and its resultant differential strengthening through the thickness, and “process factors” that includes the gradient of strength and temperature across the clad and rolling tools. (2) The major deformation mode is variable according to locations and the mixed normal-shear mode is dominant at tool contacts for initiating the failure during the V-bending test. (3) The interfacial failure mechanism of cladding featured not only in a confined deformation zone where contact directly with tools, but also the exterior area where springback after unloading caused a drastic change of stress state. These abrupt interfacial failures could be clarified via stress state and local damage analysis of the well-reproduced FE model of cladding material.

Comparative study of tube to tubesheet welding qualification on heat exchanger

Plant turnarounds are one of the most critical events in the Saudi Arabian oil and gas industries. Shutdowns have the potential to affect the plant’s cash flow and objectives either in a constructive nor a bad way. A heat exchanger is an essential equipment for some procedures in the oil and gas refineries plant and it will decide the plant’s shutdown span. In a heat exchanger, welded tube to tubesheet joint is a basic factor which requires a different qualification. In this paper, tube to tubesheet welding for various material combination (carbon steel-stainless steel, stainless steel-stainless steel, and alloy steel-alloy steel) is qualified. According to American Society of Mechanical Engineers (ASME) Section IX QW-193 mock up qualification is done and QW-193.1 to QW-193.1.3 (visual test, liquid penetrant test and macro etching test) likewise is followed and lab tested for acceptance criteria. Ten model welds are needed to determine the eligibility of each procedure according to the required standard and totally 60 models (every 20) tried to rate this 3 procedure qualification record and welder qualification test record (PQR / WQTR). Qualification of the sheet from tube to tube follows all needed variables referred to in QW-288. This study proposes the improved minimum and maximum value for current (I), voltage (V), and travel speed (mm/min) required for above said materials qualifications. Further discourse is made over the heat input (KJ/mm), after effects of minimum leak path all things considered (Macro etching test), and classifies the range qualified against utilized base material for better understanding according to QW-288 essential variables.

Enhanced interfacial strength and ductility of stainless steel/carbon steel laminated composite by heterogenous lamella structure

Interfacial performance of stainless steel/carbon steel (SS/CS) laminated composite is crucial for further manufacturing and application. Here, we reported a new strategy for fabricating the SS/CS laminated composites that composed of heterogeneous lamella structure at the cladding interface zone, by employing liquid–solid bonding and subsequent hot rolling. Different rolling temperatures were applied for comparison of the formation of heterogeneous lamella structure and their influences on the mechanical properties of the cladding interface, and the mechanisms of enhanced interfacial shear strength and ductility by the heterogenous lamella structure were discussed. A metallurgical bonding interface with intensive elements diffusion was obtained by liquid–solid bonding method, and coarse equiaxed grains and a wider decarburized layer formed at the cladding interface zone. Under rolling temperature of 900 °C, the mechanical incompatibilities of cladding interface zone and lower temperature resulted in heterodeformation and inefficient driving force of recrystallization, resulting in a heterogenous lamella structure consisted of hardened austenite region, coarse-grained ferrite region and fine-grained pearlite and ferrite region at the cladding interface zone of SS/CS laminated composite, which obviously improved the interfacial shear strength and ductility of the SS/CS laminated composites due to back stress strengthening and hardening.

Behavior of circular bimetallic tube-confined concrete stubs under eccentric compression

This paper aims to investigate the behavior of eccentrically loaded circular stainless steel-carbon steel bimetallic tube-confined concrete stub columns. 15 stub columns including bimetallic tube-confined concrete with and without bars, and concrete filled bimetallic tube were prepared and tested. The results show that the difference in the failure patterns results from the different tube steel ratio of the specimens, even the total steel ratio of the specimens is similar. The ductility of the bimetallic tube-confined concrete is better than that of the concrete filled bimetallic tube with the same parameters. Under the condition of eccentric loading, the performance of the bimetallic tube-confined concrete stub column is lower than those of the concrete filled bimetallic tube with the same parameters. The stainless steel-carbon steel bimetallic tube has a good confinement effect on the core concrete. The strengthening performance of stainless steel can effectively improve the bearing capacity of the stub in the later stage, making up for the bearing capacity reduction of the specimen caused by concrete crash. The results calculated by the traditional code formula for steel tube-confined concrete are more conservative than the test results. The difference between the test results and the calculated results increases with the decrease of diameter-thickness ratio.

Study of cracking susceptibility in similar and dissimilar welds between carbon steel and austenitic stainless steel through finger test and FE numerical model

Hot cracking susceptibility and the formation of brittle martensite phase are the main factors that limit the weldability of a dissimilar joint between carbon steel (CS) and austenitic stainless steel (SS). In this study, the self-constraint finger test was used to correlate the welding thermo-mechanical field with the crack susceptibility of a dissimilar weld between the CS ASTM A36 and SS AISI 304L. The finger test allowed to intercalate fingers (portions) of tested materials in the weld samples to produce dissimilar welds. The heat dissipation and the distortion behavior were related to the crack susceptibility, critical weld regions extension, and chemical species diffusion. Four samples were welded (two similar welds and two dissimilar welds) using the filler metals ER70S-6 and EC410NiMo. Welds were analyzed through light optical microscopy (LOM) and scanning electron microscopy (SEM) to characterize phases, detect cracks, microstructural changes, and element diffusion. A finite element (FE) numerical model was applied to simulate the welding thermo-mechanical field. FE estimations of distortion and residual stress helped to predict induced crack propagation (the initial gap between fingers) towards the fusion zone. Additionally, electrochemical tests were carried out to assess the corrosion susceptibility of the dissimilar welds. The observed cracks were produced due to different factors such as residual stress distribution, the formation of brittle and untempered martensitic phase in the fusion zone (FZ), and hot cracking associated with the weld sample distortion behavior. According to the FE estimations, the high thermal expansion of the SS was responsible for the bending curvature change in welds 2 and 4, which produced a gap between fingers and increased the crack extension in the FZ of weld 4. The dilution contributed to the formation of δ-ferrite in the FZ, which limited the growth of cold and hot cracks. The decarburization and sensitization were not observed in dissimilar welds due to the low element diffusion.

Performance of circular bimetallic tube confined concrete slender columns under eccentric compression

This paper aims to investigate the performance of thin-walled circular stainless steel-carbon steel bimetallic tube confined concrete slender columns under eccentric compression. 14 slender columns including bimetallic tube confined concrete (BTCC) with and without rebar, and concrete-filled bimetallic tube (CFBT) were tested. A parametric analysis is conducted based on the validated finite-element model. The results show that the two steel tube layers worked well together and the thin-walled BTCC specimens behaved in a ductile manner. Under the same parameters, the decrease of the diameter–thickness ratio of bimetallic tube improves the bearing capacity and rigidity of the BTCC slender column, but reduces its ductility in the descending stage. The confinement effect of bimetallic tube on the concrete in BTCC columns is stronger than that in CFBT columns. When the yield strength of stainless steel and carbon steel is similar, the stainless steel–total steel ratio has little effect on the capacity of the column. Provided meeting the requirements of corrosion resistance, relatively thinner stainless steel tube is preferred to reduce the cost. The comparison between the simulation and the calculation results shows that the current design method can predict the bearing capacity of the BTCC slender column with large diameter–thickness ratio.

Co3O4/CdS energy-storing nanocomposite: A promising photoanode for photoelectrochemical cathodic protection in the dark

In this paper, a bi-layered Co3O4/CdS photoelectrode was prepared for photoelectrochemical cathodic protection (PECP) of 304 stainless steel (SS) and Q235 carbon steel (CS). The nanoporous Co3O4 was prepared from a Co-MOF precursor using a template method, which endows Co3O4 with more active sites for redox reaction, good charge carrier migration capability, and excellent energy storage capacity. CdS nanoparticles were used as sensitizer and were deposited on the surfaces of Co3O4 using successive ion layer adsorption and reaction (SILAR) method. The results showed that Co3O4/CdS photoelectrode could provide a time-delay cathodic protection for both 304 SS and Q235 CS in the dark, satisfying the cathodic protection potentials of both metals in industry.

Simulation and Experimental Study on Three-roll Rolling of Stainless Steel-Carbon Steel Cladding Rebar

In this paper, ABAQUS is used to simulate the rolling process of stainless steel (304) and carbon steel (20MnSiV) clad steel bar by three rolls. Through analysis of different three-roll pass system, KNOCKS rolling mill system is selected as the finishing pass of rolling production line. Experimental results prove that finite element simulation result is right, it can be concluded that the thickness distribution of stainless steel-carbon steel cladding rebar rolled by KNOCKS rolling mill system cladding metal is more uniform, which can provide better finished products for the final pass rolling.

Corrosion resistance and corrosion behavior of high‐copper‐bearing steel in marine environments

AbstractThus far, research on the corrosion resistance of copper‐containing steel has been limited to Cu content of less than 1%, and the corrosion resistance of antibacterial Cu‐containing steel with Cu content above 3% has not been reported. In this study, 0Cu3 carbon steel (CS), 0Cr15Cu3 stainless steel (SS), and Q345 CS were investigated. The corrosion resistance and corrosive behavior of high‐copper (high‐Cu)‐bearing steel in a marine environment were examined by scanning electron microscopy, energy dispersive spectrometry, X‐ray diffraction, electrochemical impedance spectroscopy, and potentiodynamic polarization. Coupon test results showed that the Cu in the 0Cr15Cu3 SS and 0Cu3 CS can promote the formation of stable α‐FeOOH from γ‐FeOOH in the outer rust layers, and make the rust layers more thick and dense. In the electrochemical experiment, the impedance loop diameters and Rct values of the 0Cr15Cu3 SS and 0Cu3 CS were higher than those of Q345, while the Icorr was less than that of Q345, which indicates that the anticorrosion property of these two types of high‐Cu‐bearing steel was higher than that of Q345. The aim of this study was to define the properties of corrosion resistance and corrosive behavior in high‐Cu‐bearing steels to promote their application in marine engineering.

FEM simulation of corrosion under macro-cell mechanism

In the present study, FEM simulations have been carried out to have an accurate estimation of the electrical field in the presence of a macro-cell process, taking into account primary and secondary current distribution to update present throwing power equations. The electrochemical boundary conditions were defined comprehensively, and simulations have been performed changing water resistivity, geometry, and oxygen content. The studied systems are galvanic coupling between a stainless steel-carbon steel and also a carbon steel-zinc. As a result, an equation was proposed to predict the surfaces involved in the coupling to have an estimation of the corrosion rate.

Analytical model for estimating bending angle in laser bending of 304 stainless steel/Q235 carbon steel laminated plate

Compared with the single-component metal plate, the stainless steel-carbon steel laminated plate (SCLP) combines the stainless steel layer and the carbon steel layer with a special preparation technique. In order to estimate the bending angle of laminated plates accurately, it is of great significance to establish an analytical model. Based on the temperature gradient mechanism, the temperature distribution equation of the SCLP is established by the piecewise function. Then, the depth of the plastic zone is calculated by the recrystallization temperature according to the temperature distribution along the thickness direction of the SCLP. Moreover, by fitting the yield strength curves of stainless steel and carbon steel, the average compressive stress of the plastic zone is calculated through the integral method. By optimizing the calculation of the plastic depth and the average compressive stress in the plastic zone, the analytical model is established based on mechanical equilibrium equations. The experimental verification shows that the average error of bending angle using the proposed model is 9.95%, while Liu's model is 38.02%. The proposed model provides a calculation method for estimating the bending angle, which contributes to improving the accuracy of the analytical model in laser bending of SCLP.

Numerical Simulation of Stainless Steel-Carbon Steel Laminated Plate Considering Interface in Pulsed Laser Bending.

According to ANSYS software and an electron probe experiment, a multi-layer finite element model (FEM) of pulsed laser bending of stainless steel-carbon steel laminated plate (SCLP) including interfaces has been established. Compared with a single-layer stainless steel plate (SLSP), based on a temperature gradient mechanism considering the depth of the plastic zone, the influence of the interfaces and carbon steel layer in the model of the SCLP on the bending angle has been studied by analyzing the distributions of the temperature field, stress field and strain field in the thickness direction. The simulation results show that the temperature of the SCLP in the thickness direction is lower than that of the SLSP due to interfacial thermal resistance of the interface and fast heat conduction of the carbon steel layer, resulting in a smaller depth of the plastic zone of the SCLP defined by the recrystallization temperature. Affected by the temperature distribution, the plastic stress and strain of the SCLP in the plastic zone are smaller than those of the SLSP, leading to a smaller bending angle of the SCLP. When the laser power is 140 W, the scanning speed is 400 mm/min, the defocus distance is 10 mm, and the scanning time is 1, the bending angle of the SCLP is 1.336°, which is smaller than the bending angle 1.760° of the SLSP. The experimental verifications show that the maximum error of the bending angle is 3.74%, which verifies that the model of laser bending is usable and contributes to refining the laser bending mechanism of the SCLP.

Analysis of The Friction Welding Mechanism of Low Carbon Steel –Stainless Steel And Aluminium – Copper

Abstract Some theories of friction relevant to friction welding have been discussed. Friction welding has been done on Low Carbon Steel-Stainless Steel and Aluminium-Copper dissimilar metal combination and the results of tensile testing on the welds have been correlated to the friction mechanism. Diffusion and recrystallization appear to be the mechanism of friction welding for Low Carbon Steel-Stainless steel and cold working and upsetting seem to be the predominant mechanism for welding of Aluminium to Copper.