1. Materials and pretreatment Due to the high sensitivity of 38CrMoAl material, and the tendency of nitriding defects and nitriding rate, it is not recommended as a deep nitriding material for gears. Among them, 25Cr2MoV is the recommended gear nitriding material with good performance. After pretreatment, the conventional mechanical properties are tested and compared with the quenched and tempered state of carburized steel 20CrMnMo and 20Cr2Ni4. All indexes meet or exceed the carburizing steel. Quenched and tempered state level. Previous Next Jiangsu Minglu Stainless steel Co.,ltd , https://www.minglubolt.com
The selection of suitable materials is a prerequisite for deep controlled ion nitriding. The basic requirements for deep controlled ion nitriding steel are:
(1) It has high hardenability and ensures that the gear of a certain section size can be hardened.
(2) It has high tempering stability and ensures that the hardness of the core after nitriding for a long time does not decrease.
(3) The nitriding speed is fast, and it is not easy to produce defective tissue.
(4) The matrix has good toughness and hardness distribution.
(5) Low impurity content and few defects.
Generally, the raw materials contain alloying elements which are easy to form nitrides, such as: Cr, Mo, V, Al, etc. In the domestically used steel materials, the following materials are screened, as shown in Table 1. The strengthening level of the base material of the nitriding gear and the thickness of the hardened layer are all key factors related to the bearing capacity and service life of the gear. The deep nitriding of the gear should be comparable to the bearing level of carburizing and quenching. The gear blank must be pre-hardened and quenched to obtain uniform and fine tempered sorbite structure, as shown in Figure 1. 
