The advantage and characteristic of the drying box is that under the condition of negative pressure, the oxidation reaction can be eliminated under the condition of less oxygen content. First, the extraction vacuum and then reheating the nitrogen gas can reduce the oxidation. The steel plate for nitrogen filled vacuum oven is usually made of high quality steel plate. Compared with the usual surface spraying treatment, the steel plate has a generous appearance, which enhances its corrosion and rust resistance. From the characteristics of the product, the general shell is made of high quality steel plate. The tight box door of the nitrogen filled vacuum oven is completely adjustable by the user, and the whole forming silicon rubber door seal ensures the high vacuum in the box. The nitrogen filled vacuum oven workshop is rectangular structure, making the effective volume reach the maximum. The nitrogen filled vacuum oven electric heating tube is generally distributed around the outer walls of the equipment, so as to ensure good temperature uniformity inside the box.