Hastelloy C-276 Research Articles

Corrosion Behavior of Hastelloy C-276 in Hydrochloric and Sulfuric Acid

This research was conducted to determine the corrosion rate by varying the concentration of the solution against hydrochloric acid and sulfuric acid. The method used is open circuit potential (OCP) and Tafel plot. Based on the research conducted, Hastelloy C-276 was more prone to get oxidized in sulfuric acid rather than hydrochloric acid. It can be seen from the OCP value of sulfuric acid was much more negative than that of hydrochloric acid as of-1.5 V for 0.5 M sulfuric acid and-0.2 V for hydrochloric acid. The corrosion rate of Hastelloy C-276 in sulfuric acid was also higher compared to same alloy in hydrochloric acid. At the most concentrated solution, 0.5 M, the corrosion rate of sulfuric acid reached 0.39 mmpy and as for corrosion cate in hydrochloric acid, only at 0.16 mmpy. It is thought that there was a difference of passive film composition for both solutions. Keywords: Hastelloy C-276, Corrosion, Hydrochloric acid, Sulfuric acid.

Modelling of finishing forces on Hastelloy C-276 using ultrasonic assisted magnetic abrasive finishing process

Modelling of finishing forces on Hastelloy C-276 using ultrasonic assisted magnetic abrasive finishing process

Thermal expansion of Hastelloy C276 in low-temperature area

Thermal expansion of Hastelloy C276 in low-temperature area

Hot tensile deformation and fracture behavior of wire arc additive manufactured Hastelloy C-276

Hot tensile deformation and fracture behavior of wire arc additive manufactured Hastelloy C-276

Microstructural and Tribological Behavior of Pack-Borided Ni-Based Hastelloy C-276 Superalloy

Microstructural and Tribological Behavior of Pack-Borided Ni-Based Hastelloy C-276 Superalloy

Stabilised mechanical properties in Ni-based Hastelloy C276 alloy by additive manufacturing under different heat inputs incorporated with active interlayer temperature control

In this study, a Ni-based Hastelloy C276 alloy was prepared using cold metal transfer (CMT)-based directed energy deposition (DED) under different heat inputs with a zig-zag deposition path, integrated with active cooling and interlayer temperature control. Analogous mechanical properties were obtained for the fabricated alloys under different heat inputs (276, 368 and 553 J/mm) through effective interlayer temperature control. Such a broad processing window facilitates the large-scale industrial manufacturing and application of Hastelloy C276 by DED. Nevertheless, the lower heat input appears to slightly refine the microstructure and decrease the mechanical anisotropy of manufactured alloys, which is ascribed to combined effects of the manipulated bulk texture, refined dendrite arm spacing and reduced chemical segregation under lower heat input. Despite the variations of geometrically necessary dislocation (GND) densities with heat inputs, no significant change was observed in the average total dislocation density (TDD) in the microstructure of all samples as suggested by the peak profile analysis of Synchrotron X-ray diffraction data, which is advantageous for lowering the solidification cracking susceptibility. Moreover, all as-fabricated alloys present a typical strong fibre-type (200) crystallographic bulk texture measured by neutron diffraction, while such texture was relatively weaker in the lowest heat input condition. This work provides a reliable approach for stable additive manufacturing of Hastelloy C276 alloy, and innovatively presents rationales of stabilised properties based on the obtained insights into microstructure and bulk texture developments in a wide observation range by various techniques.

Optimization of EDM Machinability of Hastelloy C22 Super Alloys

In this study, machinability tests were carried out on a corrosion-resistant superalloy subjected to shallow (SCT) and deep cryogenic treatment (DCT) via electrical discharge machining (EDM), and the effect of the cryogenic treatment types applied to the material on the EDM processing performance was investigated. Experimental parameters, including pulse-on time (300, 400 and 500 μs), peak current (A) (6 and 10 A) and material types (untreated and treated with SCT and DCT), were used to construct the full factorial experimental design. The resulting average surface roughness (Ra) and material removal rate (MRR) results were optimized using the Taguchi L18 method. According to the Taguchi-based gray relational analysis, the optimal parameters for both Ra and MRR were determined as cryogenic treatment, pulse-on time and peak current, respectively. The response table obtained using the Taguchi method showed the most effective factors as A1BlC3 for Ra and A2B2C1 for MRR values. According to the ANOVA results for determining parameters affecting performance, peak current was the most effective factor for average surface roughness and MRR, at 74.79% and 86.43%, respectively. When examined in terms of Taguchi-gray relational degrees, the optimal parameters for both Ra and MRR were observed in the experiment performed with the SCT sample at a peak current of 6 A and 300 μs pulse-on time.

Experimental investigation of finishing forces on Hastelloy C-276 using UAMAF process

Experimental investigation of finishing forces on Hastelloy C-276 using UAMAF process

Methane-Assisted Iron Oxides Chemical Looping in a Solar Concentrator: A Real Case Study

Recent interest in hydrogen as an alternative fuel for lowering carbon emissions is funding the exploration of new ways to cleanly produce this molecule. Iron oxides can be used within a process of chemical looping. More specifically, they can lose oxygens at extremely high temperature in an inert atmosphere. An alumina receiver could not stand the extreme thermal stress, while steel (AISI 316 and Inconel Hastelloy c-276) lasted enough for the reaction to start, even if at the end of the process the receiver melted. Operating at a temperature above 1000 K helped the reaction switch from methane chemical looping combustion to chemical looping reforming, thus favouring H2 and CO yields. The gas flow outlet from the reactor reached a percentage up to 45% of H2 and 10% of CO. Carbon dioxide instead reached very low concentrations. While CO and CO2 reached a peak at the beginning of the experiment and then decreased, H2 was oscillating around a stable value. Unreacted methane was detected. The temperatures recorded in the reactor and the gas mixture obtained were used to validate a multiphysical model. The heat transfer and the chemistry of the experiment were simulated.

Effect of Heat Temperature on Microstructure and Wear Mechanism of Laser Additive Manufactured Hastelloy C22

Abstract Residual stress is easily generated in laser additive manufacturing (LAM) alloys due to high-temperature gradient during preparing, which increases the failure risk of materials. A LAM Hastelloy C22 was prepared by rotating strategy in this study, and the wear mechanism induced by heat treatment was investigated. The microstructural results showed that the columnar structure with the size of 1 ∼ 4 μm and the cellular structures with the size of 0.3 ∼ 1 μm were observed in LAM Hastelloy C22. The samples consist of γ-Ni solid solution. Cr23C6 and the increase of MoSi2 content were found as the heating temperature increased. The mechanical results presented that compared with the as-received LAM Hastelloy C22, the residual stress and wear-rate of the samples heat treated at 600 °C, 750 °C, and 900 °C were reduced by 14%, 49%, 63% and 39.9%, 68.9%, 92.3%, respectively. The wear mechanism showed that heat treatment enhanced the wear resistance of LAM Hastelloy C22 by the integrated oxide layer and supporting effect of MoSi2 and Cr23C6. This research indicated that the microstructural evolution that enhanced the wear resistance of LAM Hastelloy C22 was predominant rather than the reduced effect from relieving residual stress after heat treatment.

Comparative Analysis of Stationary and Rotary Electrode on Dry EDM in Machining of Hastelloy C276

Dry EDM is a variation of the standard EDM method in which the liquid dielectric is replaced with a gaseous medium during the machining process. This paper presents comparative analysis of stationary and rotary electrode on Dry EDM in machining of Hastelloy C276 using copper EC grade rod as electrode and air as dielectric medium. Solid cylindrical (stationary and rotary) tool electrodes are used, and high-velocity gas is fed between the electrode and the workpiece through it into the discharge gap. The high-velocity gas flow into the gap assists debris clearance and reduces tool and workpiece overheating at the discharge areas. The dry EDM technique is currently known to have reduced tool wear, a smaller discharge gap, fewer residual stresses, a smaller white layer, and a smaller heat-affected zone, in addition to being ecologically friendly. To improve response factors such as material removal rate (MRR), surface roughness (Ra), and tool wear rate (TWR), Taguchi's L9 orthogonal array approach is utilised to design the trials and study the effects of different process parameters. Discharge current (I), pulse on time (Ton), Voltage (V), pressure (P), and tool rotational speed (N) were the varied input parameters. It is observed that the rotary electrode gives better MRR compared to stationary. The analysis of results show that current (I), pulse on time (Ton) and pulse off time (Toff) are the dominant factors that influence MRR and EWR.

Temperature-Dependent Molten Chloride Salt Corrosion of Nickel Alloys

As next-generation clean and renewable energy technologies like concentrating solar power (CSP) systems and molten salt-cooled reactors (MSR) operate at ever higher temperatures (HT) to increase efficiency, their structural material and molten salt selection becomes increasingly important. To understand the corrosion behavior of candidate alloys to be used as materials for storage tanks, heat exchangers, and piping, seven alloys (Hastelloy N, Haynes 242, Haynes 214, Hastelloy C-276, Haynes 230, Haynes 224, Haynes 244) are immersed in purified 45.8 MgCl2- 38.5 KCl- 15.7 NaCl wt% chloride salt for 100 hours at 650°, 725°, and 800°C. After the exposure tests, the alloys are analyzed using SEM and EDS to determine the extent of salt infiltration and primary corrosion mechanisms. In addition, room-temperature XRD analysis provides quantitative information about the alloys’ corrosion products. These findings contribute important insight for molten salt energy system communities.

Intergranular corrosion mechanism of sub-grain in laser additive manufactured Hastelloy C22 induced by heat treatment

Corrosion protection of oil and gas equipment by advanced surface engineering technology becomes an important way to reduce cost and increase efficiency in oil and gas industry. In this work, the sensitivity of sub-grains in the laser additive manufactured Hastelloy C22 to intergranular corrosion in H2SO4/Fe2(SO4)3 solution after heat treatment was explored. The arc boundary at cross-section of melt path was preferentially corroded for the sample heated at 750 °C. The intergranular corrosion of sub-grains at melt path was caused by MoSi2 which induced Mo depletion at matrix adjacent to grain boundaries. While the intergranular corrosion was further worsened by the precipitated Cr7C3 at location of MoSi2, and it leads to pitting corrosion at grain boundaries.

Cavitation erosion/corrosion synergy and wear behaviors of nickel-based alloy coatings on 304 stainless steel prepared by cold metal transfer

Inconel 625 and Hastelloy C-276 nickel-based alloy coatings were prepared on 304 stainless steels by cold metal transfer (CMT), aiming at improving the resistance to corrosion, cavitation erosion and wear. The synergistic cavitation erosion-corrosion (SCE-C) effect of the coatings was also revealed in 3.5 wt% NaCl solution. Experimental results show that the Inconel 625 coating was composed of γ-phase matrix and MC-type carbide precipitates dominated by NbC, while the Hastelloy C-276 coating exhibited γ-phase matrix and Mo-rich p phase. Both corrosion resistance and cavitation erosion resistance of the Hastelloy C-276 coating and Inconel 625 coating were higher than that of 304 substrate, and the Hastelloy C-276 coating possessed higher corrosion resistance and cavitation erosion resistance than Inconel 625 coating as indicated by higher polarization resistance (152.95 kΩ cm2) and lower mean depth erosion rates (1.3 ± 0.15 μm/h). The carrier concentration ND of passivation film for Hastelloy C-276 coating (4.05 ± 0.01 × 1022 cm−3) was lower after 10h-cavitation erosion compared to Inconel 625 coating, indicating its passive film showing a stronger passivation behavior and protective ability. The Hastelloy C-276 coating also exhibited a higher wear resistance, and the wear mechanism was adhesive-abrasive comprehensive wear dominated by adhesive wear in the linear reciprocating wear test with Al2O3 as the friction pair. The wear resistance of Inconel 625 coating and Hastelloy C-276 coating was about 1.3 and 1.5 times that of 304 substrate, respectively. The Hastelloy C-276 coating fabricated in the present study exhibited a great potential as flow-passing parts in marine engineering fields due to the desirable resistance to corrosion, cavitation erosion and wear.

Reliable Calorimetric Method to Study the Incompatibilities between Hydrazine Hydrate and Metallic Impurities

The gold-plated crucibles used in differential scanning calorimetry (DSC) tests on hydrazine hydrate (HH) had a significant influence on the test results during a thermal risk assessment for a process to be scaled up in a pilot plant. The crucibles from four different suppliers delivered completely different test results. The subsequent Calvet calorimetry C80 test using a glass-lined Hastelloy cell could produce highly reliable thermal stability data of HH. Using the C80 test method, it was proved that high-purity gold could significantly impact the thermal stability of HH. It also effectively distinguished different impacts of metallic impurities, such as stainless steel (SS) 316 L, rust, and Hastelloy C-276 (HC276) on the thermal stability of HH.

On surface integrity of Hastelloy C-276 using chemo based ultrasonic assisted magnetic abrasive finishing process

On surface integrity of Hastelloy C-276 using chemo based ultrasonic assisted magnetic abrasive finishing process

Investigation of the characteristic properties of graphene-based nanofluid and its effect on the turning performance of Hastelloy C276 alloy

The present paper addresses an ecological machining method in turning Hastelloy C 276 Nickel alloy under different conditions such as dry, oil with least quantity lubrication (LQL), and graphene-based nanofluid LQL (NFLQL) by changing the cutting speed (31, 46, and 62 m/min) and feed rate (0.1, 0.15 and 0.2 mm/rev). Four machining responses were studied namely: surface roughness, tool wear, cutting temperature, and chip thickness. The wettability, pH value, and stability of the nanofluids were assessed prior to the machining process. The output revealed that the usage of NFLQL enhanced the machining performance in contrast to the oil LQL and dry conditions. The average reduction in the surface roughness with NFLQL condition is about 66% compared to dry machining. In addition, NFLQL gives the lowest cutting temperature (40 °C), flank wear (0.053 mm), and chip thickness (0.16 mm) respectively. In a nutshell, the effective cooling and lubrication ability of NFLQL has made significant contributions to smoother machining.

Edge cracking behavior of Y2O3 coatings by the solution deposition planarization method

As an efficient flattening technique for surface smoothing, solution deposition planarization (SDP) has recently drawn more attention as a fabrication method for second generation high temperature superconducting (2G-HTS) tapes. However, at present, it is still challenging to achieve edge crack-free surfaces while preparing a Y2O3 coating via SDP processing, especially during drying and heat treatment. Experimental results show that as the colloidal dispersion is coated and dried on a nonporous rigid substrate, the enormous stresses developed during the drying process can fracture the thin film. The finite element simulation results show that coating thickness, which is affected by the differences in pulling rate and solution concentration, is a critical factor determining the crack sies may be initiated. After optimizing the coating parameters, a 10-m long Hastelloy C-276 alloy base was successfully prepared. The average value of Ra was 1.28 nm, which is less than 5 nm (5 × 5 μm2), satisfying the industrial requirements for the preparation of superconducting materials using the IBAD (lon Beam Assisted Deposition) technology route.

Sustainable machining of Hastelloy C-276 enabling minimum quantity lubrication of environmentally compatible lubricants

Present industrial scenario attempts to achieve the sustainable manufacturing goal considering economic viability, ecological vulnerability, technological suitability and social acceptability. Also, in current manufacturing paradigm, the machining of fatigue resistance material like Hastelloy C-276 possessing vast applications in aerospace, nuclear and petroleum industries is still challenging. Consequently, leads to uneconomical process and degradation of environment during dry machining and conventional lubrication methods. The present investigations have been focused on economic and ecological sense of machining Hastelloy C-276 with reference to tool damage, surface roughness and lubrication action using different lubricating oils. The flash point, viscosity, and pH values of different oils have been measured using Pensky Marten apparatus, Fann viscometer, measuring strips and a digital pH meter. Additionally, the appearance, odour, and flow ability have been examined physically. The experimental results depicted that surface roughness has been improved by 1.5–62% during vegetable oil and 22% in used oil compared to synthetic oil at lower range of machining parameters. However, at higher levels of process variables, synthetic oil performed better than used oil by 29.2%–98.9% respectively. SEM micrograph indicated 26.17%–50% lower flank wear during vegetable oil compared to synthetic oil. However, Synthetic oil has reduced the tool wear by 3.7%–61.74% than used oil. Further, the coefficient of friction among three oils has varied from 17 to 22.5% manifesting that used oil have considerable lubrication effect. Moreover, the ANOVA analysis revealed that feed rate and lubricant type have an appreciable impact on shear angle and coefficient of friction with maximum percentage error of 3.03% and 6.38% respectively. Finally, minimum quantity lubricant (MQL) of vegetable and synthetic oil has offered a sustainable perspective due to excellent machining performance, better work place conditions, and high-tech lubrication methodology.

Experimental Investigation and Performance Optimization during Machining of Hastelloy C-276 Using Green Lubricants.

Smart manufacturing is the demand of industry 4.0, in which the mass production of difficult-to-cut materials is of great concern to fulfil the goal of sustainable machining. Presently, the machining of superalloy is of upmost interest because of its wide application. However, the limited data on the turning of Hastelloy C-276 highlights its challenges during processing. Hence, the machining performance of superalloy considering surface quality, thermal aspects and chip reduction coefficient was examined with minimum quantity lubrication of several oils to address the sustainable development goal (SDG-12). The output responses were optimized through response surface methodology along with analysis of variance. The research exhibited that the output responses were dominated by cutting speed and feed rate having a percentage benefaction of 24.26% and 60%, respectively, whilst the depth of cut and lubricant type have an influence of 10–12%. No major difference in temperature range was reported during the different lubrication conditions. However, a substantial variation in surface roughness and the chip reduction coefficient was revealed. The percentage error evaluated in surface roughness, temperature and chip reduction coefficient was less than 5%, along with an overall desirability of 0.88, describing the usefulness of the model used. The SEM micrograph indicated a loss of coating, nose and flank wear during all lubrication conditions. Lastly, incorporating a circular economy has reduced the economic, ecological and environmental burden.