Carburizing surface chemical heat treatment The carburi […]
Carburizing surface chemical heat treatment
The carburizing process is a more commonly used (more than 80%) mold surface strengthening technology, which is mainly for the surface strengthening of plastic mold cavities. After the carburizing treatment, the working parts of the mold can achieve the effect of “outer hard and inner toughness”, that is, the surface of the working part is obtained with hardness,
The performance of wear resistance, fatigue strength, etc. is improved, while the core still maintains the original plastic toughness and strength, which meets the requirements for the performance of the working parts of the mold. It has fast percolation speed, deep infiltration layer, low cost, and perfect bonding performance between the infiltration layer and the base parts.
A smooth transition between the layers is achieved. However, the operating temperature is higher (900 ~ 950 ° C), especially the ion carburizing temperature can reach 1100 ° C, and the corresponding heat treatment is required after carburizing, which leads to the possibility of deformation of the mold, so the high-precision plastic mold does not This technology is recommended.
The gas carburizing temperature is generally 920 ~ 950 ° C, comprehensive evaluation by Wang Rongbin test: the most reasonable carbon content of the surface of the carburized layer is w (C) 0.85% ~ 0.95%, the gradient of the outer layer of the carbon layer should be even and gentle. Rough martensite, excessive parasitic, reticulated carbide and black troostite are not allowed in the quenched structure. Too high a carbon mass fraction may cause malignant structures such as reticulated carbides in the microstructure of the mold parts, affecting the quality and life of the mold, and stress concentration and cracking may occur during subsequent processing.
The ion carburizing temperature is generally 900-960 ° C. Compared with gas carburizing, ion carburizing has the advantages of high efficiency, small deformation, low pollution, and can handle the surface of mold parts of any shape, and is more suitable for the surface of plastic molds and stamping molds. Strengthen the application in processing.