The basic principle of heat treatment of aluminum and aluminum alloys

As a manufacturer and supplier of aluminum products like aluminum coils, sheets, aluminum cladding etc., we are going to introduce you the basic principle of heat treatment of aluminum and aluminum alloys.

Annealing: The product is heated to a certain temperature and kept for a certain period of time and then cooled to room temperature at a certain cooling rate. Through atomic diffusion and migration, the organization is made more uniform and stable, and the internal stress is eliminated, which can greatly improve the plasticity of the material, but the strength will be reduced.

①Ingot homogenization annealing: long-term heat preservation at high temperature, and then cooling at a certain speed (high, medium, low, slow) to homogenize the chemical composition, structure and properties of the ingot, which can improve the plasticity of the material by about 20% and reduce extrusion. The pressure is about 20%, the extrusion speed is increased by about 15%, and the surface treatment quality of the material is improved.

②Intermediate annealing: also known as local annealing or inter-process annealing, in order to improve the plasticity of the material, eliminate the internal processing stress of the material, and keep it at a lower temperature for a short time, so as to facilitate continued processing or obtain a combination of properties .

③Complete annealing: Also known as finished annealing, it is held at a higher temperature for a certain period of time to obtain a softened structure in a fully recrystallized state, with the best plasticity and lower strength.

Solution quenching treatment: heat the heat-treatable-strengthened aluminum alloy material to a higher temperature and keep it for a certain period of time, so that the second phase or other soluble components in the material are fully dissolved into the aluminum matrix to form a supersaturated solid solution, and then This supersaturated solid solution is kept to room temperature by means of rapid cooling. It is an unstable state. Because it is in a high energy state, solute atoms may be precipitated at any time. However, at this time, the material has high plasticity and can be cold worked or straightened.

①On-line quenching: For some alloy materials with low quenching sensitivity, solid solution can be carried out at high temperature during extrusion, and then quenched by air cooling (T5) or water mist cooling (T6) to obtain certain microstructure and properties.

②Off-line quenching: For some alloy materials with high quenching sensitivity, they must be reheated to a higher temperature in a special heat treatment furnace and kept for a certain period of time, and then quenched into water or oil with a transfer time of no more than 15 seconds to obtain A certain structure and performance can be divided into salt bath quenching, air quenching, vertical quenching and horizontal quenching according to different equipment.