Common defects and causes of induction hardening of medium frequency furnace induction heating

    The common defects of induction hardening of medium frequency furnace induction surface are cracking, hardness is too high or too low, hardness is not uniform, hardened layer is too deep or too shallow, depth of hardened layer is uneven, and surface is partially melted. The reasons are summarized below.

    1 Causes of cracking Heating temperature is too high, uneven, Ling is too fast and uneven l improper selection of quenching liquid, cooling rate is too large; material hardenability is high, composition segregation, containing harmful elements, defects; part structure design Unreasonable, improper technical specifications.

    2 The depth of the hardened layer is too deep or too shallow. The heating power is too high (low) and the heating time is too long (short). The power frequency is not properly selected, and in this case, the fork does not select a reasonable specific power and heating time; The hardenability is too high or too low; the temperature, pressure and composition of the quenching liquid are not properly selected.

    3 The surface hardness of the workpiece is too high or too low. The material contains high or low carbon content. The tempering temperature is too low or too high and the tempering time is improper. The composition, pressure and temperature of the quenching liquid are not properly selected. The quenching heating temperature is low, and the structure has not been converted.

    4 Reasons for uneven surface hardness The structure of the sensor is unreasonable, causing heating? Uneven cooling; poor original material structure (band structure, segregation, local decarburization).

    5 The surface of the surface is locally melted. The structure of the inductor is unreasonable; the heating time is too long; the workpiece has sharp corners, holes, and grooves; the surface is defective; when it is heated continuously or half-turned, there is a sudden stop during the movement or rotation. .