The application of induction heating equipment in the quenching process is becoming more and more extensive. With the continuous improvement of this process, we generally encounter the following problems:
1. The workpiece is cracked: the heating temperature is too high and the temperature is uneven. Improper selection of quenching medium and temperature. Untimely and insufficient tempering. The hardenability of the material is high, the composition is segregated, defective, and contains excessive inclusions. The part design is not reasonable.
2. Uneven surface hardness: unreasonable structure design of the inductor, uneven heating, uneven cooling, poor material organization (with banded structure, partial decarburization), etc.
3. Surface melting: The sensor structure design is unreasonable. The parts have sharp corners, holes, bads, etc. Heating time is too long. There are cracks on the surface of the workpiece.
In the process of actually applying super frequency or high frequency induction heating to induction quenching machine of machine-heated workpieces. In order to ensure the required performance and technical requirements, in addition to preventing the above defects, it is important to consider the state and technology of the parts before and after heat treatment. request etc.
According to the characteristics of the induction heating equipment, the structure of the inductor, the working conditions of the parts, etc., combined with the following precautions, the process flow and process parameters are correctly designed to produce qualified products.
1. During induction quenching machine of parts heated with induction heating equipment, the depth and distribution of the hardened layer should be reasonably determined, which affects the stress distribution of the parts and the fatigue strength of the surface.
2. The original structure of the workpiece quenched by induction heating equipment should be normalized or quenched and tempered to ensure that the hardened layer is uniform.
3. In the process of induction quenching machine of parts, reasonable design and selection of inductors is an important means to ensure uniform heating and cooling.
4. For parts that are prone to quenching cracks, a quenching medium with moderate cooling should be selected.
5. The high frequency induction heating machine should protect the threaded holes, pin holes and oil holes on the parts, such as blocking with copper material, to prevent the parts from overheating and quenching and cracking there.
6. During the high frequency hardening process of heating parts with a high frequency induction heating machine, in order to stabilize the structure, it must be tempered immediately after eliminating the internal stress.