Process analysis of quenching heat treatment using medium frequency induction quenching equipment for blade connecting seat

The blade connecting seat is a key part on large construction machinery. Main functional components such as blades mainly rely on this part to achieve universal rotation and bear large loads, and the working conditions are harsh. It is required that the concave spherical surface of the connecting seat has high wear resistance and the overall workpiece has sufficient strength. For this reason, medium frequency induction quenching equipment is used for quenching heat treatment, and the effect is good.

1. Design, manufacturing and debugging of tooling. Considering that this research project can be widely used in large and extra-large construction machinery blade connecting seats and other parts to obtain a deeper quenching and hardening layer on the concave spherical surface to meet the requirements of large-load construction machinery products, a specially designed and manufactured medium-frequency transparent Special sensors and fixtures for thermal equipment. At the same time, sufficient technical reserves have been made for the internal and external raceways and internal and external surface quenching of various types of slewing bearings.

In order to achieve medium-frequency quenching of the blade connecting seat parts on the quenching machine tool, a tooling fixture used in conjunction with the quenching machine tool was designed and manufactured. After debugging and process verification, this set of tooling can meet the requirements for quenching the blade connecting seat.

2. Quenching process test. Induction hardening processing method is adopted where parts are scanned, moved and rotated. A dual-axis servo CNC system is used to realize the lifting and lowering movement of parts and the forward and backward movement of the transformer; the machine tool spindle is a dual-axis two-speed output, one output is used for rapid rotation of parts, realizing common parts continuous scanning quenching, simultaneous quenching, segmented continuous scanning quenching, etc. Function; the other is used for slow rotation to achieve continuous rotation quenching of spherical raceway parts. The rotation of parts is controlled by variable frequency speed regulation, and the rotation speed can be adjusted steplessly. The clamping length of the parts can be adjusted electrically to adapt to changes in the length of the quenched parts, making it easy to adjust.

3. Quenching process parameters. The process parameters of medium frequency induction heating and quenching of the blade connection seat are: transformer 12:1, voltage 480-500V, current 76-84A, and quenching water cooling pressure is 0.4MPa.

4. Result inspection

a.Quenching hardness. Randomly inspect 15 of the 75 induction-hardened parts of the blade connection seat produced, and the measured quenching hardness value is 52-54HRC, which meets the technical requirements of the product drawing.

b. Depth of hardened layer. Judging from the metallographic inspection slices of medium frequency quenching, the depth of the hardened layer of medium frequency quenching is 3-6mm, which meets the heat treatment requirements of the parts in the drawing.

c. Non-destructive testing. No defects were found during non-destructive testing of the parts after induction quenching.