The principle of die-casting mold surface treatment
Die casting molds are the main category in molds. Quickly develop in China's automobile and motorcycle industries, and the die-casting industry has ushered in a new period of development. At the same time, higher requirements are put forward for the mechanical functions of the die-casting die life. With the advancement of the times, the use of new molds that rely solely on information from time to content is still difficult to use. It is still difficult to use content. It is necessary to handle various appearances and handling capabilities, and the appearance of die-casting molds. The high efficiency. All kinds of molds, under the premise of die-casting mold tasks, are more demanding.
According to the process of repeating the task of forging and hot metal contact, the molten metal is under high pressure and high-speed die-casting molding cavity is filled. Therefore, high-heat die-casting molds with high heat loss, thermal conductivity and wear resistance are required, corrosion resistance, impact toughness, red hardness, excellent The demoulding and so on. Therefore, the appearance treatment skills of die-casting molds are relatively high. In recent years, various die-casting molds have appeared from time to time with new skills in appearance treatment, but they can generally be divided into three categories:
1) Improve skills in the traditional heat treatment process;
2) Appearance modification skills, including the appearance of thermal diffusion treatment, and the appearance of phase change to strengthen spark enhancement skills;
3) Electroplating skills, including electroless plating, etc.
The traditional heat treatment process for die-casting molds is quenching-tempering for future appearance disposal capabilities. Various information can be used as a die-casting mold, the difference between the information of the difference between the event information and the result of the same appearance processing skills and technology. Markov compares the difference between the mold substrate processing skills and the traditional process based on the appearance of the mold substrate pre-processing skills, the history, the processing technology, the improvement of the function of the mold, and the gradually mold life.
Another skill is to improve the development of bias heat treatment with the use of traditional heat treatment technology and advanced treatment process appearance and advancement of die-casting die life. The method of carbon and nitrogen infiltration treatment of chemical heat treatment, and the practical quenching and tempering process connect the NQN part (that is, the infiltration of carbon and nitrogen-quenching-carbonitriding) composite strengthening, not only the appearance of hardness, but also a useful hardening layer Depth, the additional layer hardness gradient diffusion is reasonable, tempering invariance and corrosion resistance are improved, and then die-casting the mold to obtain the appearance of excellent core parts, major advances in quality and function.
Due to the rapid cooling, the outer surface layer of the die-casting part has fine grains and finely arranged arrangement. Due to its existence, the strength of the die-casting part is higher. However, if thick-walled die-casting parts, the crystal grains of the middle layer of Zhongshan die-casting parts are coarse, which is prone to shrinkage and porosity. The mechanical properties of die castings will also decrease with the increase of wall thickness, and the amount of materials and the weight of die castings will also be added. In order to facilitate the movement of molten metal and the forming of die castings, and prevent the stress concentration of die castings and die casting molds from causing cracks, the joints between the walls of die castings generally adopt rounded corners and corners recommended by domestic and foreign design standards to strengthen abrupt transitional joints.
