论文部分内容阅读
制氧机的空气分离装置可生产大量氮气。这种氮气的含氧量低,容易净化,称为工业氮,可用作保护气的原料。一般瓶装商品氮的纯度仅为99.5～99.8%,大多数管道供氮的纯度仅为99～99.9%。故采用空分氮作保护气时,需进行除氧净化。液氮纯度虽可稳定在99.999%以上,但价格昂贵,应用受到限制。高纯氮是一种中性气氛,从理论上说,它是既不氧化又不脱碳的保护气氛。但由于在钢材入炉时带入氧、水分及各种杂质,使炉内气氛呈氧化性或脱碳性,造成钢材表面的氧化和脱碳。因此在低碳钢热处理时,往往添加2～5%氢气,使炉内气氛呈非氧化
The oxygen separator air separation unit can produce large amounts of nitrogen. This low oxygen content of nitrogen, easy to clean, known as industrial nitrogen, can be used as protective gas raw materials. The purity of nitrogen in general bottled products is only 99.5-99.8%. The purity of most pipelines supplying nitrogen is only 99-99.9%. Therefore, the use of nitrogen for shielding gas, the need for oxygen purification. Although the purity of liquid nitrogen can be stabilized at 99.999%, but the price is expensive, the application is limited. High purity nitrogen is a neutral atmosphere, theoretically it is a protective atmosphere that is neither oxidised nor decarburized. However, as the steel into the furnace with oxygen, moisture and impurities, the atmosphere was oxidizing or decarburization, resulting in oxidation and decarburization of the steel surface. Therefore, low-carbon steel heat treatment, often add 2 to 5% hydrogen, the furnace was non-oxidizing atmosphere