Impurity Elements Research Articles

Utilization of handheld LIBS and XRF analyzers for impurity detection in 3D-printed ultra-high-temperature ceramics

In this study, we implement handheld laser-induced breakdown spectroscopy (LIBS) and X-ray fluorescence (XRF) analyzers to detect elemental impurities in additively manufactured ultra-high-temperature ceramics (UHTCs). Spectral data were collected from digital light processing (DLP) 3D-printed alumina (Al2O3) samples at various processing stages. These stages included high-temperature debinding and sintering phases used to bake out organic impurities and improve grain cohesion of the ceramic. Spectral analysis revealed the presence of organic impurities such as H and C together, with inorganic impurities such as Na, Si, Ca, and Fe. A reduction in elemental impurities in the spectra was observed as the ceramic samples were processed, validating the effectiveness of handheld analyzers for in situ rapid impurity detection and quality control in the manufacturing of 3D-printed UHTCs.

Research on 4N8 High-Purity Quartz Purification Technology Prepared Using Vein Quartz from Pakistan

This study investigates the potential of two quartz vein ores from the Hunza District, Gilgit-Baltistan, Pakistan, as raw materials to obtain 4N8 high-purity quartz (HPQ) sand. Various quartz purification processes were examined, including ore calcination, water quenching, flotation, sand calcination, acid leaching, and chlorination roasting. Analytical techniques such as optical microscopy, Raman spectroscopy, and inductively coupled plasma spectroscopy were employed to analyze the microstructure, inclusion characteristics, and chemical composition of both the quartz raw ore and the processed quartz sand. Microscopic observation reveals that the PK-AML quartz raw ore has relatively high purity, the secondary fluid inclusions are arranged in a directional–linear manner or developed along crystal micro-cracks, and most intracrystalline regions exhibit low inclusion contents, while the PK-JTLT quartz raw ore contains a certain number of melt inclusions. The two processed quartz sand samples exhibit a smooth surface with extremely low fluid inclusion content. A comparative analysis of different purification processes shows that quartz sand calcination has a higher impurity removal rate than ore calcination. After crushing the raw ore into sand, the particles become finer with a larger specific surface area. Quartz sand calcination maximally exposes the inclusions and lattice impurity elements within the quartz, facilitating subsequent impurity removal through acid leaching. Following the processes of crushing, ultrasonic desliming, flotation, sand calcination, water quenching, acid leaching, and chlorination roasting, the SiO2 content of PK-AML processed quartz sand is 99.998 wt.%, with only a small amount of Ti and Li remaining, and a total impurity element content of 20.83 µg·g−1. This meets the standard requirements for crucible preparation in industrial applications, making this vein quartz suitable for producing high-end HPQ products. In contrast, the overall purity of PK-JTLT quartz is lower, and the high contents of impurity elements such as Li, Al, and Ti are difficult to remove via purification experiments. The SiO2 content of PK-JTLT processed quartz sand is 99.991 wt.%, which is applied to higher-quality glass products such as photovoltaic glass, electronic glass, and optical glass, thus presenting broad prospects for application.

Pure metals for creation the nuclear structural materials

The paper presents the main results of research on the development of structural materials for equipment elements of existing and prospective nuclear power plants. The further development of nuclear energy largely depends on the development of advanced structural materials for new generation reactors and the improvement of materials for operating nuclear power plants. The high requirements for structural materials regarding the content of impurity elements can be met only when high-purity metals are used as initial components and new technologies for their production are used. The prospects of using new methods and approaches for evaluating and improving the physico-mechanical and physico-chemical properties (microhardness, corrosion resistance, radiation resistance, etc.) of structural materials for nuclear technologies were considered.

Effect of impurities on hydrogen defect stability and migration barrier in yttrium dihydride crystal

The impurity or alloying atoms in YH2 can alter the local electronic structure and so the hydrogen defect stability, as well as the H migration barrier energy. Thus, DFT calculations were employed to determine the effect of foreign elements from alkali and alkaline earth metals to transition metals and one critical impurity element, O, on H vacancy stability and retention characteristics in YH2. Results revealed that alloying elements act as hydrogen vacancy sinks by reducing the vacancy formation energy at neighboring sites. The implantation of non-magnetic foreign elements (s1, s2, and d10 valence electrons) in hydrogen energy landscape was calculated to be minor; while the hydrogen vacancy formation energy was reduced from 1.37 eV to 1.00 eV, the migration energy barrier of hydrogen was increased from 0.87 eV to 1.15 eV for non-magnetic foreign elements. The migration energy barrier monotonically decreased with increasing d-shell occupancy, reaching as low as 0.4 eV for Cr, Mo(d4), and Fe (d4). Alloying with late transition metals (d8 and d9) moderately impacted the hydrogen vacancy formation. Finally, it was found to be O addition into the YH2- lattice did not alter the energy landscape of hydrogen vacancies. Since alloyed YH2 has not been studied extensively, this study provides an atomistic understanding how alloying elements and impurities trap vacancies and affects hydrogen mobility YH2. Meanwhile, the main findings of this study may serve as guidelines for introducing alloying elements in ZrH2 as well.

Effect of rare earth Ce treatment on the microstructure and properties of 430 ferritic stainless steel bearing Sn and Cu

The effects of rare earth Ce on purifying molten steel, modifying inclusions and micro-alloying in 430 ferritic stainless-steel bearings with Sn and Cu has been studied in this paper. The results demonstrate that Ce can purify molten steel, modify inclusions, enhance the mechanical properties and improve the pitting and corrosion resistance of the experimental steel. Ce effectively purifies the molten steel, reducing the total oxygen (T. O) content to as low as 0.00086 wt.% and sulphur (S) content to 0.0020 wt.%. The transformation of inclusions in the steel follows the sequence of MnS·Al2O3 → CeAlO3 → Ce2O2S → Ce2O3 with increasing Ce content. The number of inclusions initially decreases and then increases, with the experimental steel containing 0.012 wt.% Ce showing the best cleaning effect. Additionally, Ce treatment only slightly improves the mechanical properties of the experimental steel, but significantly enhances its pitting corrosion resistance and intergranular corrosion resistance by changing the enrichment state of carbides and impurity elements at the grain boundaries. In detail, Ce can partially inhibit the precipitation of M23C6 type carbides at grain boundaries, thereby improving the intergranular corrosion resistance of the experimental steel.

An innovative green method for efficient extraction of selenium by melt filtration-vacuum distillation

High-purity selenium is important for technological innovation in fields such as aerospace, military, new energy, and semiconductors, and has become a hot topic in developed countries. Unfortunately, traditional preparation of high-purity selenium faces challenges such as high cost, environmental pollution, and low efficiency. In this study, we introduce an innovative green method that efficiently extracts selenium from crude selenium by combining melt filtration and vacuum distillation. Our approach effectively addresses these challenges. We calculated the potential reactions of the impurities in the selenium melt and analyzed the saturated vapor pressures of various substances. The experimental results showed that volatile impurities such as PbSe and PbTe were largely removed in the form of filter residues during the melt filtration of crude selenium residue at 653 K. The filtered selenium melt was distilled for 120 min at 533 K to obtain refined Se with a total purity of 99.9 %. Through the melt filtration-vacuum distillation process, the removal rates of impurity elements Cu, Pb, As, and Te were 99.35 %, 99.97 %, 99.83 %, and 81.11 %, respectively. Impurity elements were enriched and recovered from the filter and distillation residues. The refined Se was efficiently recovered from crude selenium, and the economic benefits were superior to other processes. This process meets the demands of a clean and efficient selenium metallurgy industry.

Influence of doping elements X (X= Hf, Zr, Y, Re, Pd, Ir) on the structural stability and tension property of α-Al2O3/PtAl2-S interfaces

Pt-Al coatings are promising materials for protective materials for turbine blades in new-generation aero-engines. Therefore, it is worth noting that the interface stability and tension property between Pt-Al and the oxide layer, prolonging coating service time. However, systematic studies of doping elements effects on interface adhesion of α-Al2O3/PtAl2 with and without impurity S are still lacking. In this paper, the site preference of the six elements (Hf, Zr, Y, Re, Pd, and Ir) in the PtAl2 alloy, effects of doping elements on the interface adhesion and tension properties of the α-Al2O3/PtAl2-S interface are further explored, performing the first-principles calculation method. Considering comprehensively, Y doping has an excellent enhancement effect on the static interface adhesion and dynamic tensile strength, regardless of whether impurity element S exists in the α-Al2O3/PtAl2 interface. This study will provide necessary theoretical guidance for the composition design of Pt-Al coating and the research of new metal protective coating materials.

Effect of processing parameters and carbon to metal ratio on microstructure and mechanical properties of (MoTaTiVW)Cx high entropy carbide produced by reactive spark plasma sintering

(MoTaTiVW)Cx high entropy ceramics with varying carbon to metal ratio in the range of 0.75-0.97 were synthesized by by reactive spark plasma sintering. The effect of ball milling time on particle size, phase evolution and carbon pick-up due to toluene decomposition were studied. Formation of single-phase high entropy carbide having face-centered cubic (FCC) crystal structure was confirmed by X-ray diffraction (XRD), electron backscattered diffraction (EBSD) and Selected area diffraction pattern (SAED) analysis of the sintered compacts. Transmission Kikuchi Diffraction images revealed presence of equiaxed nature of the grains. Transmission electron microscopy images revealed the presence of an intergranular phase at grain boundaries and triple junctions. 3D-Atom Probe Tomography studies showed uniform distribution of elements within the grains with some segregation of impurity elements Fe and Co to the grain boundaries indicating minor contribution of liquid phase sintering to densification. The grain size of single-phase sintered compacts ranged between 1.69 ± 0.60 μm to 4.6 ± 1.0 μm. A low sintering temperature and higher milling time resulted in finer grain size The microhardness was found to increase with milling time and C/M ratio. The microhardness, Young’s modulus and indentation fracture toughness lied between 2221 HV0.1 to 2732 HV0.1, 370 GPa to 473 GPa, 3.6 MPa.m1/2 to 4.4 MPa.m1/2, respectively. The highest microhardness and indentation fracture toughness was found to be 2732 ± 80 HV0.1 and 4.4 MPa.m1/2 on par with reported literature for other high entropy carbides.

Variations of the elemental composition distribution over the thickness of YBa2Cu3O7-δ thin films obtained by pulsed laser deposition from one target

Epitaxial YBa2Cu3O7‒δ (YBCO) films 150-200 and 300 nm thick, respectively, were deposited on SrTiO3 (100) substrates by pulsed laser deposition at different conditions: with and without using the velocity filtration technique. The films have T(R=0) in the range of 77.4 - 87 R(T) depending on the conditions of deposition from one target with YBa2Cu3O6.8 composition. The films contain Zn, Sr, Pd, Ag and Ti impurity elements obtained from the target (a total of no more than 2 at. % ). Data of the film resistance temperature dependences, X-ray phase analysis, analysis of X-ray fluorescence (XRF) spectra and study of the surface relief by SEM methods revealed the nonuniform distributions of impurity and matrix Y, Ba, Cu elements over the film depth. Impurity concentrations near the surface lead to the formation of faceted spiral pyramids on the surface, which probably evolve into large elongated particles according to the Ostwald mechanism. This knowledge is practically important for optimizing pulsed laser deposition technologies and creating 2D instruments and devices for studying physical phenomena.

Effects of surface-active elements on wettability and interfacial reaction between DD5 superalloy and Al2O3-based ceramic shell

The study investigates the effects of oxygen-sulfur content, holding temperature, and time on the wettability and interfacial reactions between DD5 superalloy and Al2O3-based ceramic shells through non-in-situ sessile drop experiments. Lowering the oxygen-sulfur content in the DD5 master alloy, as well as reducing the holding temperature and time, leads to an increase in the wetting angle and a mitigation of interfacial reactions. Improved wettability promotes interfacial reactions, while intensified interfacial reactions further spread the alloy melt, enhancing its wettability. The main products of the interfacial reaction between the DD5 alloy and Al2O3-based ceramic shells are Al2O3 and Si, with the process being influenced by the presence of Al. When the oxygen-sulfur content is controlled within 6 ppmw, the wettability will undergo a characteristic transformation, resulting in a sharp increase in the wetting angle. It demonstrates that the ultra-pure DD5 master alloy plays a crucial role in reducing wettability and interfacial reaction, as well as slowing down the tendency of the hetero-crystal formation. Therefore, it is of great engineering significance to further reduce the content of oxygen-sulfur impurity elements in DD5 superalloy.

The effect of impurity in vanadium-rich solution on vanadium precipitation of VO2(B) by hydrothermal method

The effect of iron, aluminum, silicon and phosphorus in the vanadium-rich solution on the vanadium precipitation of VO2(B) by hydrothermal method were studied. Through the analysis of vanadium conversation efficiency, the content of V and impurity elements in precipitates and their existing form, product crystal structure and micromorphology, it is concluded that the effect following the order of P > Fe > Si > Al. As the impurity concentration increased, V content of the precipitates decreased to varying degrees, while impurity content increased. The exist of Al, Si, Fe and P could alter the diffraction peaks intensity of some crystal faces and the micromorphology of VO2(B). The high concentrations of Fe and P transformed the VO2(B) to Fe2.5V7.1O16 and Na0.45VOPO4·1.58 H2O, respectively. V and P are easily combined by covalent bonds, affecting the precipitation of VO2(B). Silicon is adsorbed on the surface of the precipitate as silica gel, thereby reducing the purity of the precipitate. The influence of impurity elements in vanadium-rich solution on the precipitation of VO2(B) by hydrothermal method is studied, which will provide a theoretical basis for the application of the new process of vanadium precipitation by hydrothermal method.

Trace and Minor Element Analysis of Azurite Blues in Fine Arts: Possibilities and Limitations in Provenance Studies.

Azurite, a historical blue mineral pigment, has previously been described to contain certain elemental impurities. These may originate from host rocks, vein fillings, or the primary copper ore mineralization. In this study, azurites (and also green malachites) from three important Central European deposits with a potential of being exploited for pigment usage already in the Middle Ages have been studied, together with azurite from Chessy, France, with a different geological setting. Using electron probe microanalysis and, more importantly, laser ablation inductively coupled plasma mass spectroscopy for trace elemental analysis, several indicators were pinpointed as important for provenance: characteristic elemental fingerprint of the deposit, e.g., elevated lead (Pb) in combination with rare earth elements, may be combined with zinc (Zn)/arsenic (As) ratio (indicating sources of excess Zn in the primary deposit) and the overall amount of metal impurities (suggesting the source mineral of copper for azurite formation). In addition, malachites from the same deposits were found to preferentially incorporate primary ore metal elements as well as Cd, Mg, Mn, or U. Therefore, if azurite pigment contains an elevated amount of malachite as an impurity, it may significantly influence the overall elemental composition. The results obtained on geological samples were applied to two micro-samples of works of art containing azurite-rich layers originating from the 13th-14th and 16th centuries. It was shown that it is highly beneficial to focus on the overall trace elemental composition of the paint layer and not on the admixed mineral grains, as their presence, especially in minute micro-samples, is largely accidental and thus not representative. Although a higher number of samples need to be studied in the future, the newly described criteria made it possible to exclude some of the localities of the employed azurite pigment. This confirmed the key importance of trace elements analysis of mineral pigments for the provenance studies of fine arts.

Universally Applicable Methods for Comprehensive Risk Assessment of Elemental Impurities in Vitamin A and D Preparations

Background: Vitamin A and D deficiency in children is a common public health problem. In China, almost all children are administered vitamin A and D preparations daily and over the long term. Children are sensitive to elemental impurities, including heavy metals. However, there are no regulatory requirements or reports on the risk assessment of elemental impurities in marketed vitamin A and D preparations. Objective: The aim of this study was to propose an accurate and efficient method suitable for samples from different manufacturers to detect elemental impurities and conduct risk assessments according to the ICH Q3D guidelines. Methods: We developed a universally applicable digestion method for capsules and an ICP–MS method for quantitative analysis of 28 elemental impurities in vitamin A and D formulations. These methods were validated according to the USP 233 guidelines. Elemental impurities in 15 batches of vitamin A and D products from 10 manufacturers and their capsule shells were determined, and risk assessment was conducted according to the International Council for Harmonization Q3D guidelines. Results: All elemental impurities of toxicological concern met the Q3D requirements. However, the concentrations of various elements, including those of lead (not detected to 4.1 µg/g), arsenic (not detected to 7 µg/g), aluminum (not detected to 888 µg/g), and palladium (not detected to 36 µg/g), varied markedly. Moreover, the lead content in one batch from one manufacturer exceeded the control threshold. Conclusion: In this study, we successfully developed an effective digestion method for processing capsules containing samples from different sources and a sensitive ICP–MS method for quantitative determination of 28 elemental impurities in vitamin A and D preparations. ICP–MS should be implemented for the evaluation and control of elemental impurities in vitamin A and D preparations. This will ensure safe long-term vitamin A and D supplementation in children

Raman characterization of lunar highlands simulants for in-situ resource utilization in a lunar setting

Lunar regolith simulants from the NU-LHT series were characterized using different configurations for performing Raman spectroscopy measurements, including with different excitation wavelengths and spot sizes. This testing was performed to explore various Raman measurement configurations for analyzing lunar regolith, especially in terms of capturing distinctive fluorescence features that can provide more information about the composition of the regolith. Results obtained utilizing configurations having a 785 nm laser for excitation showed relatively narrow, intense fluorescence signals between 870 and 890 nm, which, to the best of our knowledge, has not been observed before in lunar regolith or lunar simulant samples. These distinctive fluorescence features, attributed to a specific rare earth element (REE) impurity, adds further support that these types of features can be utilized for identification and potentially quantification of the amount of REE or transition metal impurities in lunar regolith. Further, other aspects of these Raman instrument configurations and their advantages were explored, especially those applicable for use in a lunar environment in support of in-situ resource utilization (ISRU).

The volatilization law of standard impurity elements in 3 N antimony during vacuum distillation and preparing antimony with 4 N8 content

A novel process for the production of high purity antimony (99.998 wt%) from crude antimony (3 N) by a two-step vacuum distillation was proposed. The process involves the volatilization of impurities (Mg, Na, Zn, As) with low boiling points, leaving antimony in the residue, followed by the retention of impurities (Fe, Si, Pb, Bi, Mn, Cu, Al, Au) with high boiling points in the residue. The feasibility of separating antimony from other impurities was analyzed using the theory of vacuum distillation, including saturation vapor pressure, molecular free path, and maximum volatilization rate. In the first step of vacuum distillation at 50 Pa and 630 ℃ for 60 min, zinc, sodium, and magnesium were volatilized to the gas phase, and their content were reduced to 0.17 ppm, 0.14 ppm, 0.13 ppm respectively, which meet the 5 N antimony standard. The content of arsenic was reduced to 1.21 ppm, while the antimony remains in the residue. In the second step of vacuum distillation at 1–10 Pa and 655 ℃ for 30 min, iron, lead, bismuth, manganese, copper, aluminum and gold were significantly reduced to 0.36 ppm, 0.35 ppm, 1.93 ppm, 0.05 ppm, 0.05 ppm, 0.12 ppm and 0.05 ppm, respectively, which meet the 5 N antimony standard, Therefore, the purity of volatile antimony obtained in the second step is 4 N8(99.998 wt%). This method provides reference for the preparation of high purity antimony.

Integrated textural and geochemical analysis of igneous zircon by atom probe tomography

Mechanisms relating to growth and/or compositional modification of zircon occur at the atomic scale. For felsic igneous systems, processes responsible for growth patterns in zircon have previously remained elusive as the volume of material needed to analyze these compositional features using traditional in-situ methods is considerably larger than the typical sub-micron scale distribution of trace elements. To illuminate some of these driving forces, we characterize and quantify minor and trace element concentrations in igneous zircon grains by combining methods of cathodoluminescence (CL) imaging, electron microprobe microanalysis (EMPA) elemental maps for Hf, Y, Yb and U or Th, and atom probe tomography (APT). We focus on igneous zircon from the Chon Aike Silicic Large Igneous Province (Patagonia) that provide novel insights into (1) dissolution and re-crystallization during crustal anatexis, (2) crystallization to produce oscillatory zonation patterns that are typical of igneous zircons, and (3) the incorporation of trace element impurities (e.g., P, Be, and Al) at the nanoscale. Significantly, these APT volumes provide nanoscale sampling of boundaries between oscillatory growth zones in an igneous zircon to reveal compositional zoning of Y and, to a lesser extent P, which appear as high-angle, planar features. These concentration boundaries measured on the order of 10 to 12 nm are difficult to reconcile with proposed mechanisms for generating fine-scaled oscillations. Lastly, we fit diffusional profiles to measured Y concentrations to provide an estimate on the maximum timescales of zircon growth prior to eruption, as a function of the temperature at which diffusion occurred. When combined with known pressure-temperature-time paths for the magmatic system considered, these extremely short diffusion profiles that are resolvable by APT provide a powerful method to constrain timescales of crystal growth.

Effect of CaO/Al2O3 Ratio in Fluorine‐Free Refining Slag with Low Basicity on the Cleanliness of SWRS82B Steel

A fluorine‐free quaternary CaO–Al2O3–SiO2–MgO refining slag for SWRS82B coil steel is studied by considering the requirements of the steel wire. Laboratory experiments are conducted to study the equilibrium and kinetics of steel–slag reactions. The physical and chemical properties of refining slags, including the melting temperature, viscosity, and MgO solubility, are estimated by FactSage7.2 calculation. The cleanliness of SWRS82B steel refined by slags with a basicity of 1 and C/A ratio in the range of 1.36–7.13 is studied systematically. The plasticity of inclusions is studied by phase diagram and Young modulus calculation. Deoxidizing capacity and desulfurization capacity of refining slags are discussed by kinetic calculation of steel–slag reactions based on FactSage7.2 macro‐editing and the kungliga tekniska högskolan model. Slag with a composition of 42%CaO–47%SiO2–4%Al2O3–7%MgO has the best refining effect, in which impurity elements are lowest and plastic inclusions with the smallest size and least quantity are obtained. The impurity elements oxygen and sulfur in steel can be controlled for 29 and 75 ppm, respectively. The average size of inclusions is 1.54 μm. The majority of inclusions are in a liquid state at 1600 °C and Young modulus of the inclusions ranges from 99.78 to 152.87 GPa.

Study on molten pool flow and hot cracking of narrow gap laser welding of 316LN stainless steel for fusion reactor

In this paper, narrow-gap laser welding (NGLW) of 316LN stainless steel was studied. The results indicated that continuous laser welding with filler wire (CLWFW) and pulsed laser welding with filler wire (PLWFW) can obtain good weld formation under the transition of the wire bridge, and when the pulsed laser was a trapezoidal wave, the hot cracks of the filling layer can be greatly inhibited. The intermittent output of the pulsed laser reduced the temperature gradient of the molten pool and enhanced the morphology of the caudal region of the molten pool. Meanwhile, timely liquid backfilling effectively relieved the stress concentration of the weld, thus inhibiting the generation of hot cracks. Besides, the intermittent pulse energy input had a stirring effect on the molten pool, which disturbed the growth direction of the dendrite grain and refined the grain; consequently, the impurity elements were fully diffused, and the distribution of elements in the weld center area was more uniform.

Resource utilization of coal-derived sludge and low-rank coal by multi-step thermochemical co-treatment method

Both coal-derived sludge and low-rank coal possess significant potential for resource utilization and have garnered considerable attention in recent years. The TG−DTG analysis method showed that the thermal conversion components of coal-derived sludge tended to migrate to coal and interacted with low-rank coal. The dewatering effect of low-rank coal on coal-derived sludge was investigated using the sludge-specific resistance to filtration (SRF) method. The results showed that the addition of coal promoted the transformation of interstitial water and surface water of sludge, especially the interstitial water to free water. Dewatering and deoxidation of low-rank coal and coal-derived sludge were realized by decarboxylation and C−O bond cleavage on benzene during hydrothermal co-treatment at 140−220 ℃. The average water content of hydrochar was 3.96 % after hydrothermal co-treatment, and its calorific value increased from 19.77 MJ/kg to 21.74 MJ/kg after hydrothermal co-treatment. Hydrothermal oil was produced during hydrothermal co-treatment. GC−MS analysis showed that the contents of N and S increased in the hydrothermal oil with the increase of hydrothermal temperature, indicating that the hydrothermal co-treatment can remove the impurity elements (such as N and S) contained in coal-derived sludge and low-rank coal. The pyrolysis experiments of the hydrochar at 600–900 ℃ showed that the hydrochar produced less pyrolysis gas and emitted less CO2 than the result without hydrothermal co-treatment. This study provided an effective strategy for the treatment and resource utilization of sludge and coal.

Experimental and molecular dynamics study of the hydrogen embrittlement behavior of X52 steel: Analysis of abnormal hydrogen embrittlement susceptibility

The hydrogen embrittlement (HE) susceptibility of the X52 pipeline steels in simulated hydrogen-blended natural gas (HBNG) environments were investigated with a combination of in situ high-pressure gaseous hydrogen permeation tests, slow strain rate tensile (SSRT) tests and molecular dynamics simulation, the results were compared with the X80 steel. The HE susceptibility of the X52 steel was found higher than that of the X80 steel. The mechanism of the two steels showing different HE susceptibility was analyzed from a point of permeation parameters and molecular dynamics simulation. The results showed that the X52 steel contained more impurity elements and a larger grain size, leading to a higher hydrogen solubility and a microstructure with lower HE resistance. This study suggests that the steel microstructure and the hydrogen permeation property are crucial for the understanding and prediction of the HE susceptibility of the steels.