Aluminum alloy die-casting plant | huizhou double is trustworthy
Date：
2019-07-22
Annealing of steel is a heat treatment method in which the steel is heated to the temperature of phase transition or partial phase transition, and then cooled slowly after heat preservation.
Heat treatment processes can be 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. It cools rapidly at a rate greater than the critical cooling rate 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 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 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 holes with a diameter of more than 1~31 days, 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 CausesThe 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 The most common is pinhole. Pinholes usually refer to precipitation pores less than 1mm in the casting, which are mostly circular and unevenly distributed on the whole section of the casting, especially in the thick section of the casting and the part with low cooling rate. According to the distribution and shape characteristics of precipitation pores in aluminum alloys, pinholes can be divided into three categories 1. Reticular pinholes: In the macrostructure, pinholes are closely connected to form a network, with a few large holes. It is not convenient to check the number of pinholes per unit area, nor to measure the diameter of pinholes 2. Dot shaped pinholes: the pinholes in the macrostructure are in the form of round dots. The pinholes have clear outlines and are discontinuous with each other. The number of pinholes per square centimeter can be counted and their diameters can be measured. This kind of pinhole is easily distinguished from shrinkage cavity, shrinkage porosity, etc 3. Comprehensive stomata: It is the middle type of punctate pinholes and reticular pinholes. From the perspective of macrostructure, there are many large pinholes, but they are not dots but polygonal The production practice of aluminum alloy metal die casting has proved that the main gas component of aluminum alloy forming pores due to air suction is hydrogen, and there is no certain rule to follow for its rising, often all or most aluminum alloy die castings in a furnace have pinholes; Materials are no exception. All kinds of aluminum alloys easily produce pinholes“
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