铁素体不锈钢在高温尿素环境中的腐蚀行为研究
2021-05-07 05:28:52
hualin
引言
❀对三个家私车进气程序用铁素体不绣钢板（436L、439M、441）做了车用磷酸二氢钾晶体浸蚀耐压试验，以模以铁素体不绣钢板在家私车进气程序内选用性离子液体回归器（SCR）中的渗氮浸蚀的行为。探究性学习了金属部分及混杂物对不绣钢板耐高溫车用磷酸二氢钾浸蚀的会影响，并措施EDS表现毕竟阐述了建材内部组织浸蚀的渗氮机制。科学研究表面，在高溫热震乏力和阳极氧化的信息化作用下，高溫高氮的氛围以至于铁素体不绣钢板晶界及晶内轮廓行政位置高速挥发氮化铬顆粒，发生晶界及基体轮廓行政位置贫铬。是因为436L和441不绣钢板包含较高的Mo和Nb，其耐高溫车用磷酸二氢钾浸蚀作用相关系数更为重要439M。因此，是因为436L和441不绣钢板中混杂物细微弥散，也减轻了氮化铬在混杂物的形核挥发几率比，当上升高抗高溫车用磷酸二氢钾浸蚀的其他个因素分析。
🎀至关重要词： 建筑材料不能正常工作与保护好 ; 温度高磷酸二氢钾氧化 ; 晶间氧化 ; X放射性元素能谱讲解 ; 铁素体304不绣钢 ; 渗氮不可逆性 ; 杂质物
Abstract
🔯In order to simulate the nitriding corrosion behavior of ferritic stainless steels in selective catalytic reduction （SCR） system of commercial vehicle, urea corrosion tests were carried out on three ferritic stainless steels （436L, 439M and 441） used in exhaust system of commercial vehicles. The influences of alloy composition and inclusions on high temperature urea corrosion resistance of ferritic stainless steels were investigated. The results show that under the synergistic effect of high temperature fatigue and oxidation, the high temperature and high nitrogen environment results in the rapid precipitation of chromium nitride particles at grain boundaris and in the local area of the ferritic stainless steels, resulting in chromium depletion. As 436L and 441 ferritic stainless steels contain higher Nb and Mo, thy present significantly higher resistance to high temperature urea corrosion rather than 439M. Moreover, due to the fine dispersion of inclusions in 436L and 441 stainless steels, the probability of nucleation and precipitation of chromium nitride on inclusions is also reduced, which is another cause for improving the resistance to high temperature urea corrosion of the relevant steels.
🎐Keywords： materials failure and protection ; high temperature urea corrosion ; intergranular corrosion ; EDS ; ferritic stainless steels ; nitriding mechanism ; inclusion
