Application of nitrogen in vacuum heat treatment
Release time:
2018-11-05
Application of nitrogen in vacuum heat treatment
Vacuum heat treatment (shell and tube heat exchanger) is a relatively advanced heat treatment method currently used domestically and internationally. In vacuum heat treatment, nitrogen is often indispensable.
For example, when steel parts are heated in a vacuum furnace, if the vacuum degree is too high, in order to prevent the volatilization of alloy elements in the workpiece material, an appropriate amount of nitrogen needs to be backfilled into the furnace to increase the pressure of trace gases in the furnace.
For another example, in the vacuum quenching process of vacuum heating oil quenching, sometimes in order to ensure or improve the cooling capacity of the quenching oil, sufficient nitrogen needs to be backfilled into the vacuum furnace before the workpiece is cooled. During high-pressure gas quenching, nitrogen higher than atmospheric pressure needs to be quickly filled into the vacuum furnace. During the vacuum tempering of steel parts (steel parts bending using a pipe bender), nitrogen needs to be backfilled after vacuuming to achieve uniform heating of the protective gas in the furnace and rapid cooling after tempering.
The nitrogen required for vacuum heat treatment comes from various sources. Because the density of liquid nitrogen is much greater than that of nitrogen gas, and its volume is much smaller, it is easy to transport and store, and it is also cheaper when supplied in large quantities. Therefore, liquid nitrogen is one of the important sources of nitrogen used in vacuum heat treatment. In industrial production, nitrogen is produced using a nitrogen generator.
In foreign countries and Shanghai, China, many manufacturers use large dedicated storage tanks to store liquid nitrogen transported by special vehicles from liquid nitrogen suppliers, and use the nitrogen gas gradually vaporized from liquid nitrogen for vacuum heat treatment. They believe that using liquid nitrogen is more economical than using bottled nitrogen or nitrogen generation.
Of course, whether using liquid nitrogen is more economical than using bottled nitrogen or nitrogen generation depends on the local gas source conditions and the amount of nitrogen used by the heat treatment plant. The price of liquid nitrogen is not only related to its purity, but also to the quantity purchased at one time. For example, in the spring and summer of 2003, a manufacturer of oxygen in Xiangtan sold liquid nitrogen at a price of 1 yuan per liter for purchases of 1000L or more; for retail sales, the price was 4 yuan per liter.
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Ruibang Nitrogen Purification Equipment Co., Ltd.
Telephone: 08613729920993
E-mail：ruibang@ruibang-n2.com
Address: No.5, Huaide Yayao Industrial Zone, Humen Town, Dongguan City, Guangdong Province
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