28 December 2024, Volume 44 Issue 12
    

  • Select all
    |
  • Determination of trace cadmium in nickel-based superalloy by glow discharge mass spectrometry
    OUYANG Yu, HU Jingyu, SHAO Qiuwen, HOU Yanxia, YANG Guowu
    Metallurgical Analysis. 2024, 44(12): 1-6. https://doi.org/10.13228/j.boyuan.issn1000-7571.012515
    Abstract ( )   Knowledge map   Save
    When glow-discharge mass spectrometry (GDMS) is used to determine trace cadmium in nickel-based superalloy,it is interfered by 114Sn+ and MoO+ polyatomic ions. After pre-correction with standard relative sensitivity factor(RSFStd), the mass spectral interferences of multi-atomic ions including 114Sn+ and MoO+ were corrected by interference correction equation. Thus, a method for determination of trace cadmium in nickel-based superalloy was realized by GDMS at high-resolution mode with 114Cd as analytical isotope. The instrument parameters were optimized as follows:the discharge current was 48 mA; the flow rate of discharge gas was 450 mL/min; the pre-sputtering time was 20 min. The certified reference materials of nickel-based wrought superalloy with Cd certified value less than 0.1 μg/g and Mo mass fraction of 3% were used as blank samples and determined for 11 times consecutively. The limit of election and limit of quantifiation, which were calculated according to three-fold and ten-fold of standard deviation of blank sample, were 0.081 μg/g and 0.27 μg/g, respectively. The content of cadmium in certified reference material or reference material of nickel-based superalloy were determined according to the proposed method, and the results were in good agreement with the certified value/standard value. The relative standard deviations(RSD,n=6) were less than 12%. The contents of cadmium in 3 nickel-based superalloy samples were determined according to the proposed method as well as inductively coupled plasma tandem mass spectrometry (ICP-MS/MS),respectively. The results showed that the results of the above two methods were basically consistent.
  • Determination of trace selenium,cerium,zirconium,tantalum and tellurium in nickle-based alloy N06625 by inductively coupled plasma mass spectrometry
    FAN Xin, ZHAO Yanbing
    Metallurgical Analysis. 2024, 44(12): 7-13. https://doi.org/10.13228/j.boyuan.issn1000-7571.012537
    Abstract ( )   Knowledge map   Save
    The contents of Se,Ce,Zr,Ta and Te in nickel-based alloy will affect its processability, thermoplasticity, fatigue performance and creeping property. Therefore, their determination is of great significance. The sample was dissolved with hydrochloric acid, hydrogen peroxide and hydrofluoric acid. 78Se, 140Ce, 90Zr, 181Ta and 125Te were selected as test isotopes. The calibration curve was prepared by standard addition method to overcome the matrix effect. 103Rh was used to correct 78Se and 90Zr, while 115In was used to correct 140Ce, 181Ta and 125Te. Consequently, a method for simultaneous determination of trace Se, Ce, Zr, Ta and Te (mass fraction below 0.005%) in nickel-based alloy N06625 was established by inductively coupled plasma mass spectrometry (ICP-MS). The results showed that the correlation coefficients of calibration curves of elements were all higher than 0.999 0. The limits of detection and limits of quantification were 0.004 5-0.38 μg/g and 0.015-1.28 μg/g, respectively. The samples of nickel-based alloy N06625 were determined according to the proposed method. The relative standard deviations (RSD, n=11) of determination results of 5 elements were between 0.87% and 9.9%, and the recoveries were between 92% and 107%. The proposed method was applied for determination of trace Se, Ce, Zr, Ta and Te in sample of nickel-based alloy N06625. The results of Se and Te were basically consistent with those obtained by hydride generation atomic fluorescence spectrometry(HG-AFS), and the results of Ce and Zr were basically consistent with those obtained by inductively coupled plasma atomic emission spectrometry(ICP-AES).
  • Determination of calcium fluoride in low-grade fluorite tailings by ion chromatography after alkali fusion
    ZHANG Zhuojia, LIU Jie, ZHOU Jiaolian, XIE Lifang
    Metallurgical Analysis. 2024, 44(12): 14-20. https://doi.org/10.13228/j.boyuan.issn1000-7571.012516
    Abstract ( )   Knowledge map   Save
    The accurate determination of calcium fluoride content in low-grade fluorite tailings is of great significance for the evaluation and improvement of comprehensive recycling process.The semi-quantitative component analysis of low-grade fluorite tailings sample was first conducted by wavelength dispersion X-ray fluorescence spectrophotometer (WDXRF) and X-ray diffractometer (XRD). It was found that fluorine mainly existed in the form of calcium fluoride, and the sample mainly contained silicon, aluminum, iron, calcium, magnesium, potassium, sodium, sulfur and manganese. 4.0 g of potassium hydroxide and 0.35 g of potassium nitrate were used as flux. The sample was melted at 650 ℃ for 8 min and then leached with hot water. IC-Na pretreatment column was used to separate alkaline earth and transition metal cations such as aluminum, iron, calcium, magnesium and manganese. Thus, a method for determination of calcium fluoride in low-grade fluorite tailings was established by alkali fusion-ion chromatography. The results showed that the mass concentrations of cations such as aluminum, iron, calcium, magnesium and manganese in test solution were all lower than 0.1 μg/mL after separation with IC-Na pretreatment column. Therefore, the interference of these elements with the determination could be ignored. The calibration curve was drawn with the mass concentration of fluorine ion as x-axis and its corresponding peak area response as y-axis. The results indicated that its correlation coefficient was 0.999 6 with calcium fluoride in range of 1-30 μg/mL. Two fluorite tailings samples and one reference material of fluorite ore were determined according to the proposed method. Meanwhile, different amounts of high-grade fluorite ore certified reference material were added for recovery tests. The recoveries were between 96% and 104%. The proposed method was applied for determination of calcium fluoride in low-grade fluorite tailings samples and fluorite ore reference materials. The relative standard deviations (RSD, n=7) were between 0.54% and 1.5%. The results were consistent with those obtained by ion selective electrode method or the standard values. The proposed method was applicable for determination of calcium fluoride in low-grade fluorite tailings samples with mass fraction in range of 5%-60%.
  • Determination of volatile phenol in sediment by flow injection analyzer with alkali solution extraction
    LI Xiaohui, HU Xinying, GAO Zhijun, SUN Huiying, YU Yahui, LIU Chunxia
    Metallurgical Analysis. 2024, 44(12): 21-26. https://doi.org/10.13228/j.boyuan.issn1000-7571.012518
    Abstract ( )   Knowledge map   Save
    It is of great significance for ecological environment protection to determine accurately and efficiently volatile phenol content in sediment. The liquid-solid ratio was controlled at 15∶1. Volatile phenol in the sample was extracted with 10 g/L sodium hydroxide solution after oscillation at 180 r/min for 15 min. Meanwhile, 3.0 g of copper sulfate was added to remove the interference of sulfides in the sample. Thus, the determination of volatile phenol in sediment was realized by flow injection analyzer. The results showed that the mass concentration of volatile phenol in range of 0.02-1.0 mg/L exhibited linear relationship to its corresponding peak area with correlation coefficient of 0.999 9. The limit of detection and lower limit of determination for this method were 0.08 mg/kg and 0.32 mg/kg, respectively. Three sediment samples with different concentrations of volatile phenol content in sediment were determined according to the proposed method, and the relative standard deviations (RSD, n=6) of determination results were between 0.83% and 1.4%. Two types of sediment sample were selected for recovery tests with three content levels, respectively. The recoveries were between 93% and 104%. The contents of volatile phenol in six sediment samples were determined according to the proposed method as well as 4-ampyrone spectrophotometry in standard method of HJ 998-2018. The results of the two above methods were basically consistent.
  • Determination of lithium oxide in lithium ore by inductively coupled plasma atomic emission spectrometry with super microwave digestion
    LIANG Yuefeng, YAN Zhuowen, TANG Manna, XUAN Jianwen, XIAO Dahui, HE Yingxian
    Metallurgical Analysis. 2024, 44(12): 27-32. https://doi.org/10.13228/j.boyuan.issn1000-7571.012555
    Abstract ( )   Knowledge map   Save
    The content of lithium oxide in lithium ore is the key factor affecting the price of lithium ore. The atmospheric decomposition method is commonly adopted for the determination of lithium oxide in lithium ore, but it has some problems such as complicated operation and large consumption of acid. The sample was treated with 1.5 mL of sulfuric acid and 2.0 mL of hydrofluoric acid by super microwave digestion at 280 ℃. After digestion, the solution was continuously heated until sulfuric acid fuming to remove silicon and excessive hydrofluoric acid. The salts were redissolved with 1.0 mL of sulfuric acid and 25 mL of water by heating, and lithium in the test solution was determined by inductively coupled plasma atomic emission spectrometry (ICP-AES) with Li 610.365 nm as analytical line and emission power as 0.95 kW. Consequently, a method for determination of lithium oxide in lithium ore was established by ICP-AES after super microwave digestion. The mass concentration of lithium in range of 0.50-50.0 mg/L showed good linear relationship with its corresponding emission intensity. The correlation coefficient (r) was 0.999 7. The limit of detection of this method was 1.5 mg/kg for lithium oxide. The contents of lithium oxide in three lithium ore samples were determined according to the proposed method, and the relative standard deviations (RSD, n=8) of determination results were between 0.92% and 2.0%. The proposed method was applied for determination of two certified refence materials of lithium ore, and the results were consistent with the certified values. Two assay laboratories were selected for determination of the contents of lithium oxide in lithium ore samples according to the proposed method, and the results were consistent. Compared with the current standard methods of GB/T 509.1-2008 and GB/T 17413.1-2010, this method could save 80% of hydrofluoric acid dosage during digestion, and it is suitable for rapid inspection and clearance of imported and exported lithium ore.
  • Determination of 8 elements in spodumene by inductively coupled plasma atomic emission spectrometry with alkali fusion
    YANG Yanhui, LIAO Shiying, CHEN Ge, ZHANG Jie, JIANG Xianfang, CHEN Yijun
    Metallurgical Analysis. 2024, 44(12): 33-39. https://doi.org/10.13228/j.boyuan.issn1000-7571.012570
    Abstract ( )   Knowledge map   Save
    Calcium, magnesium, iron, silicon, aluminum, manganese, beryllium and phosphorus in spodumene are determined by the series of methods 3, 4, 5, 6, 7, 8 and 10 in industrial standard YS/T 509-2008 of Methods for chemical analysis of spodumene and lepidolite concentrates. The results are accurate, but there are many kinds of reagents used and the process is complicated. After the spodumene sample was treated by alkali fusion with sodium hydroxide at 630 ℃ for 15 min, it was acidified and leached with hydrochloric acid (1+3). By selecting the optimal analytical lines of elements, the contents of calcium, magnesium, iron, silicon, aluminum, manganese, beryllium and phosphorus in spodumene were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES). The calibration curve was drawn by matrix matching method to eliminate the influence of matrix effect. The linear correlation coefficients of calibration curves for elements were all higher than 0.999 7. The limits of quantification of elements were between 0.061 5 μg/g and 123.9 μg/g. The contents of calcium, magnesium, iron, silicon, aluminum, manganese, beryllium and phosphorus in two spodumene samples were determined according to the proposed method, and the relative standard deviations (RSD, n=7 or n=8) of determination results were all less than 2.5%. The contents of calcium, magnesium, iron, silicon, aluminum, manganese, beryllium and phosphorus in certified reference material of spodumene were determined according to the proposed method. The relative errors (RE) of determination results were between -5.00% and 7.31%.
  • Effect of heat treatment temperature and time on phase variation of decomposition product of crystalline aluminum chloride
    BAI Jian, QU Zhi, ZHANG Yunfeng, REN Xudong
    Metallurgical Analysis. 2024, 44(12): 40-46. https://doi.org/10.13228/j.boyuan.issn1000-7571.012545
    Abstract ( )   Knowledge map   Save
    Effect of heat treatment temperature and time on phase variation characteristic of decomposition product of crystalline aluminum chloride was investigated. The composition and microtopography of crystalline aluminum chloride were analyzed and discussed by inductively coupled plasma atomic emission spectrometer (ICP-AES) and metallographic microscope. The results showed that the purity of crystalline aluminum chloride was relatively high. It contained trace impurity elements such as sodium and calcium, and it belonged to orthorhombic structure. While, aluminum oxide showed irregular elliptic with particle size of 100-210 μm. The phase change characteristics of decomposition product were investigated with thermal gravimetric analyzer and X-ray diffractometer (XRD). The results showed that the crystalline aluminum chloride lost small amount of free water under heat treatment at 80-100 ℃. The decomposition rate after 120 min was 6.95%, and the phase was still crystalline aluminum chloride. The decomposition rate was 35.84% after heat treatment at 150 ℃ for 120 min. The decomposition rate was 87.31% after heat treatment at 200 ℃ for 120 min. The decomposition velocity at 600-1 200 ℃ was very fast, and the sample could be completely decomposed within 5 min. The decomposition rate of crystalline aluminum chloride was in direct proportion to heat treatment temperature and time, and heat temperature was the dominant factor. When the heat treatment temperature was 200-700 ℃, the decomposition product phase was ρ-type or amorphous aluminum oxide. When the heat treatment temperature was 800-1 000 ℃, the decomposition product phase was mainly in γ-type, δ-type and or η-type aluminum oxide. Wherein, a small amount of α-type aluminum oxide was observed in decomposition product at 1 000 ℃. When the heat treatment temperature reached 1 200 ℃, all phases were converted into α-type aluminum oxide with most stable energy. This study provided data basis for the theoretical research and pilot equipment selection in heat treatment of crystalline aluminum chloride in the laboratory. It also provided data support for the process parameter optimization in heat treatment of crystalline aluminum chloride.
  • Uncertainty evaluation for determination of niobium in IN718 nickel-based superalloy by inductively coupled plasma atomic emission spectrometry and analysis of rapid evaluation method
    WANG Xiangde, LIU Hanxiao, BAI Zhanming, GU Xusheng, YANG Xueru, LIU Kai
    Metallurgical Analysis. 2024, 44(12): 47-54. https://doi.org/10.13228/j.boyuan.issn1000-7571.012532
    Abstract ( )   Knowledge map   Save
    The determination uncertainty could intuitively reflect the quality control level of determination process. With the issue and implementation of standards such as GB/T 22553, Top-down method has attracted more and more attention. The determination uncertainty of niobium content in IN718 nickel-based superalloy was evaluated and compared based on Top-down method and GUM method. It was found that the uncertainty evaluated by reproducibility standard deviation (sR) in Top-down method was much higher than that in GUM method. The related references about the uncertainty evaluation of metal materials in recent years were analyzed. The simplified Top-down method was used. The ratio (U(Rw)/U(w)) of the uncertainty evaluated by intermediate precision to the uncertainty evaluated by GUM method was treated by robust statistical method. It was found that the robust mean value was 1.20, and the robust standard deviation was 0.48, indicating that the evaluation results of the two above methods were in good agreement. Compared to GUM method, the simplified Top-down method did not require to identify the components of weighing, certified reference material and repeatability. Moreover, the complicated calculation and combination were not necessary. The evaluation process was simple and easily conducted. The proposed method could help the laboratories evaluate the uncertainty conveniently and rapidly, which could promote the improvement of laboratory quality control level.
  • Determination of arsenic in magnesium and magnesium alloy by hydride generation atomic fluorescence spectrometry
    XUE Ning, SUN Gaihua
    Metallurgical Analysis. 2024, 44(12): 55-59. https://doi.org/10.13228/j.boyuan.issn1000-7571.012585
    Abstract ( )   Knowledge map   Save
    With the increasing application of magnesium and magnesium alloy, there are more and more requirements for the determination of harmful element arsenic. The sample was dissolved in nitric acid in batches by heating at low temperature. Then the acidity was adjusted with hydrochloric acid followed by adding 10 mL of thiourea-ascorbic acid solution in order to reduce As(Ⅴ) to As(Ⅲ). Thus, a method for determination of trace arsenic in magnesium and magnesium alloy was established by hydride generation atomic fluorescence spectrometry (HG-AFS). Since there are many product types and groups of magnesium and magnesium alloy, such as magnesium-aluminum series, magnesium-zinc series, magnesium-manganese series, magnesium-lithium series and magnesium-rare earth series, the effects of magnesium matrix as well as the maximum content of aluminum, zinc, manganese, copper, nickel, lithium, lanthanum, cerium, praseodymium, neodymium, gadolinium, yttrium, erbium and dysprosium in magnesium alloy on the determination of arsenic were investigated. The results showed that the interference of magnesium matrix and major alloying elements in magnesium alloy with the determination of arsenic could be ignored. It was found that the mass concentration of arsenic in range of 1.00-10.00 μg/L had linear relationship with its corresponding fluorescence intensity. The correlation coefficient of calibration curve was 0.999 7. The limit of detection of method was 0.001 4 μg/g, and the limit of quantification was 0.004 2 μg/g. Three magnesium alloy samples were determined according to the proposed method, and arsenic standard solution was added for recovery test. The relative standard deviations (RSD, n=6) of determination results were between 2.4% and 5.3%, and the recoveries were between 98% and 106%. The method comparison tests indicated that the determination results of the proposed method were basically consistent with those obtained by inductively coupled plasma mass spectrometry (ICP-MS).
  • Method optimization for determination of chromium(Ⅵ) in site soil based on alkali solution extraction
    LI Jing, DING Dongmei
    Metallurgical Analysis. 2024, 44(12): 60-65. https://doi.org/10.13228/j.boyuan.issn1000-7571.012534
    Abstract ( )   Knowledge map   Save
    It is of great significance to determine chromium (Ⅵ) accurately in site soil for the management and remediation of contaminated site. Alkali solution extraction-flame atomic absorption spectrometry is one of the main analysis methods for determination of chromium (Ⅵ) in site soil. The certified reference materials and actual samples of site soil were used as research object, and the effects of heating method, stirring speed, liquid-solid ratio and reducing remediation reagent on the determination of chromium (Ⅵ) were investigated. The results showed that the extraction of chromium (Ⅵ) in site soil was more complete when the water bath heating was used, and the stability of determination results were better than that of electrical heating. The stirring rate could significantly affect the determination results of chromium (Ⅵ), and the continuous and steady medium speed stirring showed best effect. Under normal conditions, the liquid-solid ratio of 10∶1 could satisfy the effective extraction of chromium (Ⅵ) in conventional soil samples. However, for the site soil samples with chromium (Ⅵ) content exceeding the upper limit of linear range of calibration curve, the optimal liquid-solid ratio should be obtained by reducing sample mass to ensure the accuracy and reliability of determination results. The reducing remediation reagent had negative interference with the standard addition tests of chromium (Ⅵ). Hydrogen peroxide was added before extraction followed by ultrasonic reaction at room temperature for 5 min. It could change the reducing properties of sample matrix, and meanwhile, keep the chemical form stability of chromium (Ⅵ) in soil sample. The spiked recoveries of chromium (Ⅵ) increased to 75.0%-97.5%. Therefore, the interference of reducing remediation reagent with the spiked recovery test of chromium (Ⅵ) could be effectively eliminated.
  • Determination of silicon in chromium carbide by silicon molybdenum blue spectrophotometry with alkali fusion
    XU Hua, ZENG Zhiping, SHI Yihua, CHEN Chao, CHEN Jiarong
    Metallurgical Analysis. 2024, 44(12): 66-71. https://doi.org/10.13228/j.boyuan.issn1000-7571.012539
    Abstract ( )   Knowledge map   Save
    The accurate determination of silicon content in chromium carbide is of great significance for the quality control of products. The sample was fused with sodium peroxide. After leaching with hot water and acidification, chromium was removed by volatilization with hydrochloric acid. Under certain acidity conditions, silicon could react with ammonium molybdate to form silicon molybdenum yellow. The mixture of oxalic acid and sulfuric acid was added to eliminate the interference of phosphorus and iron, and ascorbic acid was added to reduce silicon molybdenum yellow to silicon molybdenum blue for spectrophotometric determination at 810 nm. Thus, a method for determination of silicon in chromium carbide was established by silicon molybdenum blue spectrophotometry with alkali fusion. The results showed that the mass concentration of silicon in range of 0.05-1.20 μg/mL showed good linear relationship with its corresponding absorbance with correlation coefficient of 0.999 9. The apparent molar absorptivity was ε=22.41×103 L·mol-1·cm-1. The limit of detection and limit of quantification for this method were 0.001 7% and 0.005 2%, respectively. The interference tests of coexisting ions showed that the residual chromium in test solution as well as phosphorus and iron in sample had no interference with the determination of silicon. The contents of silicon in three chromium carbide samples were determined according to the proposed method, and the relative standard deviations (RSD, n=9) were between 0.51% and 5.8%. Two chromium carbide samples were conducted for standard addition recovery tests, and the recoveries were between 97% and 102%.
  • Determination of manganese in ferroboron by sodium periodate oxidation spectrophotometry
    MENG Wei, LI Yahua, ZHOU Shengqiang
    Metallurgical Analysis. 2024, 44(12): 72-77. https://doi.org/10.13228/j.boyuan.issn1000-7571.012541
    Abstract ( )   Knowledge map   Save
    Manganese could enhance the toughness of ferroboron. The accurate determination of manganese is helpful for the production of high-quality ferroboron alloy materials. The sample was dissolved in aqua regia at low temperature and digested by perchloric acid fuming. Manganese was oxidized to septivalent with sodium periodate in sulfuric acid-phosphoric acid medium and then determined at 530 nm by spectrophotometry. Thus, a method for determination of manganese in ferroboron was established by periodate sodium oxidization spectrophotometry. The samples were treated by three methods, i.e., perchloric acid fuming in presence of sulfuric acid and phosphoric acid, perchloric acid fuming followed by adding sulfuric acid-phosphoric acid, and slag dissolution with acid. The results showed that the determination results of manganese in ferroboron samples were basically consistent by the three methods above. The determination results of manganese in certified reference materials/reference material of ferroboron were consistent with the certified values/standard value. Wherein, the operation of perchloric acid fuming followed by adding sulfuric acid-phosphoric acid was the most simple. The determination range of method was 0.050%-1.00% (mass fraction, the same below). The correlation coefficient of calibration curve was 0.999 99. The apparent molar absorptivity was 2.3×103 L·mol-1·cm-1. The limits of detection and limits of quantification for this method were 0.004% and 0.012%, respectively. The contents of manganese in certified reference material and actual samples of ferroboron were determined according to the proposed methods. The relative standard deviations (RSD, n=11) of determination results were between 0.25% and 0.46%. The contents of manganese in three certified reference materials/reference material and two actual samples of ferroboron were determined according to the proposed methods. The determination results of certified reference materials/reference material were consistent with the certified values/standard value, and the determination results of actual samples were consistent with those obtained by slag dissolution with acid-inductively coupled plasma atomic emission spectrometry (ICP-AES).
  • Effect of molybdenum on oxide scale of martensitic stainless steel 40Cr13Mo after full hydrogen batch annealing
    PAN Hongtao, LI Zhaoguo, ZHANG Youyu
    Metallurgical Analysis. 2024, 44(12): 78-83. https://doi.org/10.13228/j.boyuan.issn1000-7571.012506
    Abstract ( )   Knowledge map   Save
    The oxide scale samples of full hydrogen batch annealing steel coil of 40Cr13Mo and 40Cr13 produced by the same process were analyzed by scanning electron microscopy (SEM), X-ray energy dispersion spectrum (EDS) and X-ray diffraction (XRD). The results showed that the oxide scale of stainless steel 40Cr13Mo was dense with low peeling degree due to the addition of Mo. Only few small defects were observed inside. There was pressure stress in some parts and the strength was slightly higher than that of oxide scale. The bonding regions with matrix were colloidal, and there were “small wedge prominences” of 2FeO·SiO2 (fayalite) with pinning depth of 0.81 μm. The oxide scale thickness was small but the range was large, and the bonding surface with matrix was uneven. The energy distribution trend of Cr was consistent with O in EDS surface scanning. The high-level regions accounted for above 90%, which were distributed in middle and lining of oxide scale. The middle-level regions of 10% were distributed in periphery of oxide scale, and there were no low-level regions. In the bonding regions with matrix, Si showed continuous middle-level stripes with width of 3 μm, and there were 3 μm high-level spots in stripes. The reduction process of oxide scale with hydrogen lagged behind seriously. The phases were mainly FeCr2O4 and FeO. Their contentsaccounted for 90.2% (mass fraction, the same above), and the contents of Fe, Cr and Cr0.7Fe0.3 were only 9.6%.
  • Quantitative inversion of bolt fatigue fracture based on Paris formula and finite element verification
    ZHAO Rui, ZHONG Zhenqian, FU Hang
    Metallurgical Analysis. 2024, 44(12): 84-92. https://doi.org/10.13228/j.boyuan.issn1000-7571.012501
    Abstract ( )   Knowledge map   Save
    Accurate prediction of bolt fatigue life is very important to guarantee the engineering safety and draw up the maintenance plan. Paris formula is a model which is widely accepted in fatigue analysis. The importance of Paris formula in fatigue life calculation was discussed by analyzing the fatigue fracture of 10.9-grade bolts for pressure vessel. Moreover, the accuracy of Paris formula in failure prediction was also verified. The chemical element analysis, metallographic structure analysis and electron microscopy observation were conducted. The fatigue bands were measured and the data fitting of fatigue band width was performed for the inversion of the fatigue life of two bolt fracture. The results indicated that the crack propagation life of #1 bolt and 2# bolt were 17 251 cycles and 19 549 cycles, respectively. The finite element model verification results showed that the crack propagation life of #1 bolt and 2# bolt were 16 228 cycles and 18 525 cycles, respectively, which were in good agreement with the proposed data. The relative error of fatigue life between the analogue simulation and calculation result were not more than 6%. It was indicated that Paris formula could be used for the accurate prediction of bolt failure under certain conditions, and it provided reliable reference for the improvement of structural part safety.
Copyright © Metallurgical Analysis, All Rights Reserved.
Tel: 010-62182398　
E-mail：yjfx@analysis.org.cn
Powered by Beijing Magtech Co. Ltd,.