Formation and prevention of carbon black during carburizing and carbo-nitriding heat treatment
Feihong Heat Treatment Heat Treatment Co., Ltd. uses a sealed box-type multi-purpose furnace with an intelligent control system. The drip atmosphere is mainly applied to the decomposition of methanol and propane at high temperatures to produce active carbon, which provides a carbon source for carburizing and carbonitriding heat treatment processing.
Methanol and propane in carburizing heat treatment are hydrocarbons, which produce carbon black when the decomposition is incomplete or the active carbon produced by decomposition cannot be completely absorbed by the workpiece. Carbon black adheres to the surface of the workpiece, which will affect the effect of carburizing or carbonitriding on the one hand, and seriously affect the appearance of the workpiece on the other.
Methanol is completely cracked at high temperature, and the output gas is clear and bright when dripping exhaust, and the increase of dripping volume will not produce foggy atmosphere, and the carbon black will be produced only after long time and high flow rate. The high temperature decomposition product of methanol is mainly CO and H2, which is not easy to form carbon black. Cracking temperature 650 ℃, below this temperature will increase the H2O content in the atmosphere. Methanol has weak carburizing ability, can be used as a carrier gas, and is a good diluent.
Propane cracking produces clear gas, and in the process of carburization and carbonitriding, the decomposition gas component decomposes carbon with the participation of metal surface, part of which is absorbed by the metal and part of which coalesces into carbon black, and no direct decomposition of carbon particles is found. Therefore, the main attention is paid to the carbon absorption area and the supply quantity during the application process to avoid producing a large amount of carbon black. Propane has a strong carburizing ability and can be used as a carbon source.
Feihong heat treatment in the production of some practical experience, carburizing, carbonitriding products in the heat treatment process, the front side of the tooling, the side of the addition of iron plate can block carbon black attached to the surface of the workpiece.