What is annealing? What is the purpose of annealing? What are the common annealing processes?

What is annealing? \x0d\ Heat treatment process of heating the steel whose structure deviates from the equilibrium state to an appropriate temperature, keeping it at this temperature for a certain period of time, and then slowly cooling (along with furnace cooling) to obtain the structure close to the equilibrium state. What is the purpose of \ x0d \ x0d \ annealing? \x0d\ What are the common annealing processes for reducing hardness, improving cutting performance, demagnetizing and relieving stress \ x0d \ x0d \1? Types of annealing \x0d\ Heat treatment process in which the steel whose structure deviates from the equilibrium state is heated to an appropriate temperature, kept at this temperature for a certain period of time, and then slowly cooled (along with furnace cooling) to obtain a structure close to the equilibrium state. There are many kinds of annealing processes for \x0d\ steel, which can be divided into two types according to the heating temperature: one is annealing above the critical temperature (Ac 1 or Ac3), also known as phase transformation recrystallization annealing, including complete annealing, incomplete annealing, spheroidizing annealing and diffusion annealing; The other is annealing below the critical temperature, including recrystallization annealing and stress relief annealing. \x0d\ 1。 Complete annealing and isothermal annealing \ x0d \ Complete annealing is also called recrystallization annealing, generally referred to as annealing. This kind of annealing is mainly used for casting, forging and hot rolling profiles of various carbon steels and alloy steels with sub-* * composition, and sometimes it is also used for welding structures. It is generally used for the final heat treatment of some light workpieces or the preheating treatment of some workpieces. \x0d\ 2。 Spheroidizing annealing \ x0d \ Spheroidizing annealing is mainly used for carbon steel and alloy tool steel (such as steel used for manufacturing tools, measuring tools and dies). Its main purpose is to reduce hardness, improve cutting performance and prepare for quenching in the future. \x0d\ 3。 Stress relief annealing \ x0d \ Stress relief annealing, also known as low temperature annealing (or high temperature tempering), is mainly used to eliminate the residual stress of castings, forgings, weldments, hot-rolled parts and cold-drawn parts. If these stresses are not eliminated, steel parts will be deformed or cracked after a certain period of time or in the subsequent cutting process. \x0d\\x0d\ Process mode tools: continuous annealing furnace, vacuum annealing furnace and box annealing furnace can be used.