Painted steel with heat treatment process

Heat treatment process generally includes three heating, heat preservation, cooling process, sometimes only two heating and cooling process. The process to connect to each other, completely. Heating is one of the important steps of heat treatment. Paint a steel heating with heat treatment method are many, the first is to use charcoal and coal as a heat source, and application of liquid and gas fuel. The application of electric heating is easy to control, and no environmental pollution. The heat source can be used to direct heating, but can be by molten salt or metal, and floating particles with indirect heating. When heated to paint play clad steel belt, steel belt exposed to air, oxidation and decarburization (often happen The steel parts surface carbon content lower) , which on the surface of the parts after heat treatment performance has a very adverse effect. And painted steel belt usually should be in controlled atmosphere or protection atmosphere, molten salt and a vacuum heating, coating or packing method to protect the heating is also available. The heating temperature is one of the important process parameters of heat treatment process, selection and control of heating temperature, is a major problem to ensure the quality of heat treatment. Heating temperature is processed and varies the purpose of the metal material and heat treatment, but is usually heated to above phase transition temperature, in order to obtain the tissues that need it. Another change will take time, so DangTu paint a steel belt is achieved when the heating temperature of workpiece surface, must be in the temperature keeping time, make internal and external temperature, the microstructure change completely, this paragraph of time is called the heat preservation time. Heating with high energy density and surface heat treatment and heating speed, in general, there is no holding time and holding time is very short, and the chemical heat treatment of heat preservation time tend to be long.