In China, heat treatment processes are roughly divided into the following categories:

1. Annealing of steel: heating the steel to a certain temperature and holding it for a period of time, and then cooling it slowly, which is called annealing. Annealing of steel is a heat treatment method that heats the steel to the temperature where phase transformation or partial phase transformation occurs, and then slowly cools it after heat preservation. The purpose of annealing is to eliminate the structural defects, improve the structure, homogenize the composition and refine the grains, improve the mechanical properties of the steel and reduce the residual stress; At the same time, it can reduce hardness, improve plasticity and toughness, and improve cutting performance. Therefore, annealing is not only to eliminate and improve the organizational defects and internal stress left by the previous process, but also to prepare for the subsequent process. Therefore, annealing belongs to the heat treatment of semi-finished products, also known as pre heat treatment

Aluminum alloy die casting; Zinc Alloy Die Casting; Aluminum Alloy Die Casting Factory; Zinc Alloy Die Casting Plant; Dongguan Aluminum Alloy Die Casting; Dongguan Zinc Alloy Die Casting; Hardware die-casting; Die-casting die

2. Normalizing of steel: normalizing is a heat treatment method that heats the steel to above the critical temperature, makes the steel all transform into uniform austenite, and then cools it naturally in air. It can eliminate the network cementite of hypereutectoid steel, refine the lattice of hypoeutectoid steel by normalizing, improve the comprehensive mechanical properties, and it is economical to replace the annealing process with normalizing for parts with low requirements

3. Quenching of steel: Quenching is a heat treatment method that heats the steel above the critical temperature, keeps it warm for a period of time, and then quickly puts it into the quenchant to make its temperature drop suddenly, and rapidly cools it at a speed greater than the critical cooling speed, so as to obtain an unbalanced structure mainly composed of martensite. Quenching can increase the strength and hardness of steel, but reduce its plasticity. Quenchants commonly used in quenching include water, oil, alkaline water, salt solution, etc

Cast aluminum rotor is one of the important components of the motor, and its quality will directly affect the efficiency, power factor, temperature rise, starting and running performance of the motor. Porosity refers to the holes with a diameter greater than 1~31TI1TI, which are distributed inside, on or near the surface of the conductor and have round, elliptical and irregular shapes. The uneven distribution of Dongguan die-casting is characterized by porosity, and the inner surface of the hole is generally smooth. At present, in the motor manufacturing industry of our country, when the die-casting process is used to produce the cast aluminum rotor, the air hole is a common problem and is difficult to eradicate. The reasons are various, which are related to the working state of the die-casting machine, the selection of die-casting process parameters, the structure of the die-casting die, the lamination of the rotor core, the smelting process of aluminum and aluminum alloys, and the operation of the die-casting process

Cause

The main cause of porosity is that the filling degree of the pressure chamber is not enough, which causes the gas to occupy a certain space in the pressure chamber, and the gas and aluminum liquid enter the die casting mold cavity at the same time during injection. The process measures taken are as follows:

Oil storage between rotor blades

The oil entrapment between rotors is one of the main causes of porosity in cast aluminum rotors. Dongguan die-casting Because the rotor die-casting is a process formed at high temperature, high pressure and instantaneously, when the aluminum liquid just fills the rotor cavity, the high-temperature aluminum is still liquid and reacts with the oil between the rotor sheets, gas is generated. Some of this gas is escaped, and some is surrounded by aluminum liquid. However, the aluminum liquid solidifies rapidly, and the surrounding gas cannot escape. Therefore, these gases remain in the cage bar and end ring of the rotor in the form of bubbles, and are distributed irregularly

4. Steel tempering: reheat the quenched steel to a certain temperature and then cool it with a certain method, which is called tempering. The purpose is to eliminate the internal stress generated by quenching, reduce the hardness and brittleness, and obtain the expected mechanical properties. Tempering is divided into high temperature tempering, medium temperature tempering and low temperature tempering. Tempering is usually used together with quenching and normalizing

(1) Quenching and tempering treatment: the heat treatment method of high temperature tempering after quenching is called quenching and tempering treatment. High temperature tempering refers to tempering at 500 - 650 ℃. Quenching and tempering can greatly adjust the properties and materials of steel, and its strength, plasticity and toughness are good, with good comprehensive mechanical properties

Aluminum alloy die casting; Zinc Alloy Die Casting; Aluminum Alloy Die Casting Factory; Zinc Alloy Die Casting Plant; Dongguan Aluminum Alloy Die Casting; Dongguan Zinc Alloy Die Casting; Hardware die-casting; Die-casting die

(2) Aging treatment: in order to eliminate the size and shape changes of precision measuring tools or molds and parts during long-term use, the workpiece is often reheated to 100 - 150 ℃ after low temperature tempering (low temperature tempering temperature 150 - 250 ℃) and kept for 5-20 hours before finishing. This treatment is called aging for stabilizing the quality of precision parts. It is particularly important to age treat steel components under low temperature or dynamic load conditions to eliminate residual stress and stabilize steel structure and size