①Using high-pressure bottled gas such as hydrogen, nitrogen, ammonia or ammonia.

② Use an ammonia decomposition device to decompose ammonia, and use the hydrogen-nitrogen mixed gas generated by it, or the gas obtained after combustion treatment (mainly nitrogen).

④Use other substances (natural gas, propane, methanol, ethanol, acetone, isopropanol, ethyl acetate, urea or kerosene) directly into the furnace to decompose the gas formed by thermal decomposition. These methods are often used in combination to obtain an atmosphere of the required ingredients. For example, the endothermic gas is used for carburizing, and the enriched gas-propane is often added. When using industrial nitrogen (bottled nitrogen, nitrogen produced directly from the air with a nitrogen generator or molecular sieve, etc.), it is often dripped into the furnace at the same time Organic liquid, forming a so-called nitrogen-based atmosphere, and so on.

The controlled atmosphere is mainly used to protect metals from oxidation or decarburization, such as hydrogen, hydrogen, ammonia decomposition atmosphere, exothermic atmosphere, etc., called protective atmosphere. The atmospheres that can perform chemical heat treatment on the surface of steel parts-carburizing, nitriding, etc. are called carburizing atmosphere, nitriding atmosphere, etc.