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原文
High temperature corrosion of the exhaust valve Now commonly used in the shipping market, poor quality fuel contains a large number of vanadium, sodium and sulfur and other elements. In the combustion process. Sulfur, vanadium and sodium and other elements to form sulfur dioxide, vanadium pentoxide and sodium oxide (depending on the chemical composition of these oxides excess oxygen and combustion temperature). Between the oxide to react with the oil but also in the calcium response, the formation of low melting point salts, there are sodium sulfate, calcium sulfate and sodium vanadate and other various ingredients. Mixtures of these salts is generally 535 ° C melting point of about the same time has a strong corrosive. When the part temperature at 550 ° C or more, enough to make the vanadium and sodium in the molten state of Taiwan material, attached to the part surface. When the exhaust valve at work, due to the reasons for the exhaust (valve temperatures up to 650? 800 ° C and above), it formed a liquid deposited on the valve plate and valve seat and valve stem with the transition area on the surface. Even then it is corrosion-resistant alloy steel will corrode, corrosion results in the formation of pitting on the sealing cone, pits. Pit connected to the leak could result. As a result of corrosion is produced under high temperature conditions, so called "high-temperature corrosion." In the high-temperature corrosion of harmful elements to the dangers of the largest vanadium.
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译文：
　　　　目前在航运市场上普遍使用的劣质燃油中含有大量钒、钠和硫等元素。在燃烧过程中．硫、钒和钠等元素形成氧化硫、五氧化二钒和氧化钠等(这些氧化物的化学成份取决于过量氧气和燃烧温度)。氧化物之间要发生反应，而且还要与滑油中的钙反应，形成低熔点的盐类，有硫酸钠，硫酸钙和不同成份的钒酸钠等。这些盐类混合物熔点一般为535°C左右，同时具有较强的腐蚀性。当零件温度在550°C以上时，足以使钒、钠化台物处于熔化状态，附着于零件表面。当排气阀在工作中时，由于排气原因(气阀温度可达650?800°C以上)，使它以液态形成沉积在阀盘及阀座以及阀杆与阀面的过渡表面上。这时即使是非常耐腐蚀的硬质合金钢也会受到腐蚀，腐蚀结果在密封锥面上形成麻点、凹坑．凹坑相连就可能造成漏气。由于上述腐蚀是高温条件下产生的，所以称之为“高温腐蚀”。在上述高温腐蚀的有害元素中以钒的危害性为最大。

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