The cylinder liner is heat treated using medium frequency induction heating equipment or super audio frequency induction heating equipment

The inner surface of the cylinder is easily worn due to the action of high-temperature and high-pressure gas and contact with the high-speed moving piston. In order to improve the wear resistance of the cylinder and extend the service life of the cylinder, we often use ultrasonic induction heating equipment or medium frequency induction heating equipment to heat treat the cylinder. Today, we will talk about the process specifications of the cylinder liner heat treatment.

In the past, cylinder liners usually used the overall quenching process, but there were many defects. Now we usually use the induction quenching process. The advantages of using induction quenching are as follows:

1. Energy saving

2. It can be produced on an assembly line, and the productivity is many times higher than that of overall quenching.

3. The depth of the hardened layer can be selected according to needs.

Cylinder liners are generally made of pearlitic gray cast iron, and their as-cast structure has stricter requirements. The hardness of the casting is 170-241HBW. The quenching hardness of the cylinder liner is generally required to be ≥43HRC. The depth of the hardened layer is 1.5-2.5mm. The quenching area is allowed to have transition zones at both ends, such as the upper end ≤15mm, the lower end ≤25mm, etc.

(1) Induction hardening. Depending on the depth of the hardened layer, ultrasonic induction heating equipment or medium frequency induction heating equipment can be used. The power depends on the diameter of the cylinder liner. For example, if the cylinder liner has an inner diameter of 25mm and a height of 292mm, select a power of 160 - 200kW. When using a quenching machine with alternate working stations, the productivity can reach 90 pieces/h. During scanning quenching, the heating temperature and time have a great influence on the quenching results. The scanning speed used in production is 6-7mm/s, that is, the heating time of the particle is about 3s (the effective circle width is 20mm), and the heating temperature is 900°C. Around 10%, better quenching results can be obtained (fine needle-like martensite and troostite structures).

(2) Tempering. The cylinder liner is tempered using a power frequency tempering machine. The three-station power frequency tempering machine can temper 3 cylinder liners at a time. There are 6 cylinder liners symmetrically arranged in a row of 3 on the rotating worktable. The worktable can rotate back and forth 180°. When the first row of 3 cylinder liners When the cylinder liner is undergoing power frequency tempering (the tempering temperature is generally between 200 - 220°C, and the tempering time is generally about 40 seconds), the cylinder liner to be tempered can be installed on the three vacancies in the other row. When the first row of cylinder liners is tempered, the power frequency tempering coil automatically rises, the workbench rotates 180°, the coil descends, and the tempering of the second row of three cylinder liners begins. The power frequency cylinder liner tempering sensor has a built-in silicon steel core, and the coil is made of multi-layer, multi-turn flat copper wire. Its productivity exceeds the quenching machine's productivity of 90 pieces/h, reaching 180 pieces/h, and can be used in production combinations. arranged on the production line.

Zhengzhou Gou's is a manufacturer specializing in the production of medium frequency induction heating equipment and ultrasonic induction heating equipment. The equipment produced has complete functions and is easy to operate. It is a good equipment for quenching cylinder liners and other workpieces. If you want to know more information about the equipment, please feel free to leave us a message.