After a semester's study of Fundamentals of Mechanical Manufacturing, I have a brand-new and comprehensive understanding of this subject. Let me talk about my understanding of it.
First of all, mechanical manufacturing means that auxiliary materials such as blanks (or materials) are input into the mechanical manufacturing system as raw materials, and after storage, transportation, processing, inspection and other links, qualified parts or products are finally output from the system. Generally speaking, mechanical manufacturing is the sum of all kinds of labor that transform raw materials into finished products. The main contents include: heat treatment, casting, forging, forging, welding, metal cutting and surface machining of tools and parts. I mainly introduce the understanding of the role of heat treatment, casting and mechanical manufacturing of steel in the national economy.
The heat treatment process generally includes three processes of heating, heat preservation and cooling, and sometimes there are only two processes of heating and cooling. These processes are interrelated and uninterrupted. Heating is one of the important processes of heat treatment. There are many heating methods for metal heat treatment. Charcoal and coal were first used as heat sources, and later liquid and gas fuels were used. When the metal is heated, the workpiece is exposed to air, which often leads to oxidative decarbonization (that is, the carbon content on the surface of steel parts is reduced), which has a very adverse impact on the surface properties of parts after heat treatment. Therefore, metals should usually be heated in controlled or protective atmosphere, molten salt and vacuum, and can also be protected by coating or packaging.
Heating temperature is one of the important process parameters of heat treatment process, so the selection and control of heating temperature should be increased.