Microstructure of 40Cr Vacuum Heat Treatment
In the manufacture of parts such as machine tools, the performance requirements are high, and the heat treatment process is often used to improve the performance of parts. Vacuum heat treatment is an advanced heat treatment method which has characteristics such as environmental protection, energy saving and quality assurance. 40Cr is a common material used in high-end machine tool parts. Vacuum heat treatment can improve its physical and mechanical properties. In this paper, the microstructure of 40Cr after vacuum heat treatment is studied in detail.
The experiment uses 30CrMnTi steel for vacuum heat treatment at 850 °C, the holding time is 45 minutes and the quenching medium is quenching oil. After the heat treatment of 40Cr steel, the microstructure of the specimen is observed by optical microscope and scanning electron microscope (SEM). From the metallographic structure of the specimen observed by optical microscope, it can be seen that there are some small pearlite and Martensitic lattices in the structure of 40Cr steel, the matrix of the microstructure contains a lot of small Martensite and white crystal particles scattered in it. The grain size is mostly tiny.
The scanning electron microscope (SEM) was used to observe the microstructure of 40Cr steel. The results showed that the microstructure of 40Cr steel is composed of Martensite and white crystal particles, which are evenly distributed in the martensitic matrix. The grain size of Martensite is relatively large and the grain size of white particles is relatively small, forming a dual-phase microstructure. In addition, some grain refinement phenomenon is visible in the structure, which means that the grain size becomes smaller and some uniform-spherical grains are visible.
The results show that the microstructure of 40Cr steel is a dual-phase microstructure composed of Martensite and white crystal particles, the Martensite and the white crystal particles are evenly distributed in the matrix. The presence of the white crystal particles leads to the refinement of the structure and makes it more uniform and stable. This type of microstructure characteristics are beneficial to the machinability, hardness and wear resistance of 40Cr steel after heat treatment, thus improving the performance of the material and ensuring its high precision and long-term use.
In summary, after vacuum heat treatment of 40Cr steel at high temperatures, the microstructure of the material is Martensitic, pearlite and white crystal particles, the distribution of the particles is even, and the grain refinement phenomenon is obvious, thus enhancing the physical and mechanical properties of the material and improving its performance.
