李富天,刘光明,刘欢欢,何一鹏,李玉,柳志浩.高温水蒸气环境中TP439不锈钢的应力腐蚀开裂敏感性[J].表面技术,2024,53(2):71-77, 96.
LI Futian,LIU Guangming,LIU Huanhuan,HE Yipeng,LI Yu,LIU Zhihao.Stress Corrosion Cracking Susceptibility of TP439 Stainless Steel in High Temperature Water Vapor[J].Surface Technology,2024,53(2):71-77, 96 |
| 高温水蒸气环境中TP439不锈钢的应力腐蚀开裂敏感性 |
| Stress Corrosion Cracking Susceptibility of TP439 Stainless Steel in High Temperature Water Vapor |
| 投稿时间：2022-12-02 修订日期：2023-03-02 |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.02.006 |
| 中文关键词: 铁素体不锈钢 高温水蒸气 慢应变速率拉伸试验 应力腐蚀开裂 断口形貌 |
| 英文关键词:ferritic stainless steel high temperature vapor slow strain rate tensile test stress corrosion cracking fracture morphology |
| 基金项目:国家自然科学基金(51961028) |
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| Author | Institution |
| LI Futian | School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China |
| LIU Guangming | School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China |
| LIU Huanhuan | School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China |
| HE Yipeng | School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China |
| LI Yu | School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China |
| LIU Zhihao | School of Material Science and Engineering, Nanchang Hangkong University, Nanchang 330063, China |
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| 中文摘要: |
| 目的 研究TP439不锈钢在高温水蒸气环境中的应力腐蚀开裂行为，并探讨水蒸气和温度对其应力腐蚀开裂敏感性的影响规律。方法 采用慢应变速率拉伸试验方法研究了TP439不锈钢在400~600 ℃水蒸气环境中的应力腐蚀开裂行为，利用SEM和EDS分析试样断口区域的形貌及元素分布。结果 同一应变速率(2×10‒5 s‒1)下，随着温度在400~600 ℃范围内升高，TP439不锈钢在空气和水蒸气环境中的屈服强度、抗拉强度和断裂能均逐渐降低，延伸率逐渐增大。400 ℃和500 ℃时，试样在水蒸气环境中的抗拉强度较空气环境中有所降低，而延伸率较空气环境中增大。600 ℃时试样在水蒸气环境中的力学性能较空气环境中无明显差别。试样在400、500、600 ℃水蒸气环境中的应力腐蚀开裂敏感性指数分别为0.7%、1.2%和‒2.8%，应力腐蚀开裂敏感性较低。试样在400~600 ℃水蒸气环境中的断口均呈现韧性断裂特征，断口形貌整体由韧窝和微孔组成，颈缩现象显著，断口附近未发现二次裂纹。温度在400~600 ℃范围内升高时，断口的韧窝特征更加明显，颈缩程度逐渐增大，600 ℃时断口侧面的氧化膜表面Cr含量明显降低，主要由Fe的氧化物形成。结论 水蒸气对TP439不锈钢的应力腐蚀开裂行为起促进作用。基于应力腐蚀开裂敏感性指数和断口的分析，在应变速率为2×10‒5 s‒1的400~600 ℃水蒸气环境中，TP439不锈钢的应力腐蚀开裂敏感性较低。 |
| 英文摘要: |
| The stress corrosion cracking behavior of TP439 ferritic stainless steel in high temperature water vapor environment was studied, and the influence of water vapor and temperature on its stress corrosion cracking susceptibility was discussed. The stress corrosion cracking susceptibility of TP439 stainless steel in the water vapor environment at 400-600 ℃ was investigated by a slow strain rate tensile test. The material used in the test was TP439 ferritic stainless steel, the main components were as follows:17.95wt.% Cr, 0.47wt.% Ti, 0.41wt.% Mn, 0.22wt.% Ni, 0.061wt.% Cu, 0.026wt.% Mo, 0.007wt.% Al, 0.44wt.% Si, 0.029wt.% P, 0.017wt.% C, 0.01wt.% N, 0.005wt.% S, and the balance was Fe. The test strain rate was 2×10‒5 s‒1, the test environment was high-temperature air and high-temperature water vapor (10%Ar+90%H2O), and the oxidation temperatures were 400 ℃, 500 ℃, and 600 ℃, respectively. A scanning electron microscope (SEM, Quanta 2000) was used to observe the fracture morphology of the sample, and an energy dispersive spectrometer (EDS, INCA) was used to analyze the oxidation product composition near the fracture. Under the same strain rate (2×10‒5 s‒1), with the rises of temperature in the range of 400-600 ℃, the yield strength, tensile strength and fracture energy of TP439 stainless steel in air and water vapor environment gradually decreased, the elongation increased gradually. At 400 ℃ and 500 ℃, the tensile strength of the samples in the water vapor environment were lower than those in the air environment, the elongation was increased compared with those in the air environment. At 600 ℃, the mechanical properties of the samples in the water vapor environment were not significantly different from those in the air environment. The stress corrosion cracking susceptibility of the samples in 400 ℃, 500 ℃, and 600 ℃ water vapor environments were 0.7%, 1.2% and ‒2.8%, respectively, and the stress corrosion cracking susceptibility was low. The samples exhibited ductile fracture in the water vapor environment at 400-600 ℃. The fracture morphology was composed of dimples and micropores, and the necking phenomenon was significant. No secondary cracks were found near the fracture. The stress corrosion cracking susceptibility of the sample was low. When the temperature was increased in the range of 400-600 ℃, the dimple features of the fracture were more obvious, the fracture area gradually narrowed, and the degree of necking gradually increased. In the water vapor environment at 400-600 ℃, the main elements of the oxide film near the fracture of the sample were Fe, Cr, O. At 400 ℃ and 500 ℃, the oxide film on the surface of the sample was smooth and level, and the atomic percentages of Cr were 17.21% and 11.20%, respectively. When the temperature rose to 600 ℃, many fine whisker-like oxides were observed on the surface of the oxide film near the fracture of the sample. The Cr content on the surface of the oxide film decreased to 1.36%, mainly composed of oxides containing Fe. Water vapor promotes the stress corrosion behavior of TP439 stainless steel. Based on the analysis of stress corrosion cracking susceptibility index and fracture morphology, the stress corrosion cracking susceptibility of TP439 stainless steel is low in water vapor environment at 400-600 ℃ with strain rate of 2×10‒5 s‒1. |
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