Heat treatment of metal: The so-called metal is a technological operation that artificially changes the internal structure and structure of metal alloy through certain thermal action (sometimes combined with mechanical action, chemical action or other actions) to obtain the required properties.
Incomplete positioning: according to the different processing requirements of the workpiece processing surface, the number of positioning support points is less than 6, which is called incomplete positioning.
Friction welding: a pressure welding method that uses the heat generated by the mutual friction between the surfaces of weldments to make the end face reach a thermoplastic state, and then quickly upsetting to complete the welding.
Heat treatment of metal: The so-called metal is a technological operation that artificially changes the internal structure and structure of metal alloy through certain thermal action (sometimes combined with mechanical action, chemical action or other actions) to obtain the required properties.
Homogenization annealing: Diffusion annealing is used to eliminate or reduce the non-heat treatment of as-cast alloys.
Annealing based on recovery and recrystallization: When the metal after cold deformation is heated to a certain temperature, recovery and recrystallization will occur, and the deformation texture will also change, thus eliminating the metastable state caused by cold deformation to a certain extent and making the metal material obtain the required microstructure, structure and properties.
Annealing based on solid phase transformation: This is based on the diffusion phase transformation of solid metal alloy after high temperature insulation and cooling.
Quenching: Fixing a metal from a solid high-temperature state to room temperature in the form of supercooling or supersaturation, or transforming a high-temperature phase into a metastable state of another crystal structure when cooling, which is called quenching. Quenching in which the crystal structure does not change during quenching is called non-polymorphic transformation quenching. If the crystal structure type of metal alloy changes during quenching, it is called polycrystalline phase transformation quenching.
Aging or tempering: maintaining or heating to decompose supersaturated solid solution at room temperature.
Chemical heat treatment: a kind of heat treatment that organically combines thermal action and chemical action.
Thermomechanical treatment: it is a comprehensive process that combines the deformation strengthening of plastic deformation with the phase transformation strengthening of time, so that the forming process and final properties can be unified.
Critical concentration: Any alloy with composition concentration greater than K will have non-equilibrium surplus phase under the cooling condition of the casting. K concentration is called critical concentration.
Aggregation and spheroidization: Aggregation is the coarsening process of excess phase particles, which is characterized by the dissolution of small-sized particles and the growth of large-sized particles. Spheroidization is a special form of aggregation, that is, excess phase particles that are not equiaxed are transformed into nearly equiaxed shapes. Function: After the metal workpiece is heated to a certain temperature, it is immersed in cooling liquid (oil, water, etc.). ), and the performance of the cooled workpiece is better and more stable.
Cold deformation energy storage: the free energy increment of cold deformation belongs to it and is the driving force of microstructure change of cold deformation metal. Recovery: The essence of recovery process is point defect movement and dislocation movement and recombination.
In-situ recrystallization: with the increase of annealing temperature or annealing time, the subgrain formed by multilayer and cellular substructure will gradually coarsen through subgrain boundary migration and subgrain merger. Under certain conditions, subgrain can grow to a large size, which is called in-situ recrystallization.
Hardening effect of low-temperature annealing: The hardness, strength, especially yield limit and elasticity of some metals and alloys not only do not decrease, but increase, which is the so-called hardening effect of low-temperature annealing.
Recrystallization: From a certain annealing temperature, the microstructure of cold deformed metal has changed obviously, and new grains can be observed even at a small magnification. This phenomenon is called recrystallization.
Recrystallization temperature: The temperature at which recrystallization begins is defined as recrystallization temperature.
Thickness effect: The phenomenon that the grain size is controlled by the thickness of the plate is called "thickness effect".
Texture braking: The texture generated at the completion of recrystallization may slow down the growth rate of recrystallization grains, which is called "texture braking".
Critical deformation degree: recrystallization occurs from a certain deformation degree, and extremely coarse grains are obtained. This deformation degree is called critical deformation degree.
Secondary recrystallization: when certain conditions are met, some single grains may grow rapidly and devour the surrounding recrystallization matrix, and eventually the whole material will be composed of coarse grains. This phenomenon is called secondary recrystallization.
Annealing texture: after annealing, due to the orientation relationship between nucleation and growth, there will generally be preferred orientation, that is, annealing texture.
Comprehensive kinetic curve of phase transition (TTT diagram): the phase transition kinetic curve data at different temperatures are synthesized at temperature,
The comprehensive kinetic curve (temperature-time-transition curve) of phase transition is obtained, which is called C curve or TTT diagram.
Habitual surface: When many alloys undergo solid-state phase transformation, a new phase is often formed on a specific crystal plane in the parent phase, and this crystal plane of the parent phase is called habitual surface.
Initial grain size: the initial grain size of austenite refers to the grain size when austenite is just completely formed at a certain heating temperature.