Nitrogen is mainly used as protective gas and purging gas in iron and steel enterprises. For example, nitrogen should be used as injection gas in slag splashing process. Nitrogen is also used for powder injection, instrument gas and gas plugging. Argon is mainly used to improve the quality of steel.

Argon is used to blow into molten steel to make the composition of molten steel uniform. It can purify molten steel, remove impurities such as hydrogen, oxygen and nitrogen dissolved in molten steel, and improve the quality of billet. The comprehensive nitrogen consumption is 80-120 m3 / T steel and 3-4 m3 / T steel for ironmaking, steelmaking and rolling.

The production of air separation plant is mainly used as protective gas, such as steel rolling, zinc plating, chromium plating, heat treatment (especially thin steel plate) continuous casting, etc. The protective gas should be nitrogen, and the purity of high-purity nitrogen should be above 99.999%.

The chemical inertness of argon is used to smelt special metals, such as lithium, beryllium, uranium, plutonium, titanium, zirconium, hafnium, niobium, tantalum and other rare metals needed in the reduction reaction in aerospace industry. Argon should be used as the ambient gas. In order to protect the crystal growth of aluminum alloy doors and windows, argon should be used as ambient gas in the process of refining semiconductor materials Si, GE and preparing single crystal.

Argon is also used in steelmaking process: for example, argon is blown into molten steel to make the composition of molten steel uniform, the molten steel is purified, and the impurities such as hydrogen, oxygen and nitrogen dissolved in molten steel can be removed, so as to improve the quality of steel billet. Argon blowing can also cancel the reduction cycle, shorten the smelting time, increase production and save electric energy. Argon blowing protection is an important means to improve steel quality, which has been adopted by most steel plants in China.