The reason why cracks occur after induction quenching parts are quenched by ultrasonic induction quenching equipment. Generally speaking, the reasons for quenching cracking are the increase in volume due to the formation of martensite, excessive internal stress caused by shrinkage during quenching and cooling, or excessive structural stress and thermal stress. Where the stress of the workpiece is concentrated, quenching cracks are more likely to occur. Therefore, to solve the problem of quenching cracks, in addition to the induction heating process factors, the rationality of the product design structure is also a very important aspect in eliminating quenching cracks. Whether the selection of materials is reasonable is another important factor.
Today, we will first look at the process factors. After induction quenching parts are quenched by ultrasonic induction quenching equipment, cracks caused by improper induction quenching process and their solutions. See the table below for detailed analysis.
|
Phenomenon |
Reason |
Solution |
|
Uneven heating temperature or overheating |
1) Poor sensor design and manufacturing, resulting in uneven local temperature or overheating.
2) The electrical specifications of the heating device are out of control, the power is too large or the heating time is too long.
3) The relative position of the workpiece and the sensor is incorrect and the operation sequence is wrong.
|
1) Improve design and manufacturing quality
2) Correct the shortcomings of the control system
3) Strictly operate process procedures to address problems
|
|
Poor cooling, uneven cooling. |
1) Improper selection of quenching cooling medium
2) Poor structural design of the sprayer
3) Improper formulation or management of quenching cooling medium procedures (improper concentration, flow rate, time, and improper maintenance of sprayers).
|
1) Select the appropriate quenching cooling medium and control the critical cooling rate and martensite cooling rate.
2) Improve design
3) Improve the formulation and execution of cooling procedures
|
|
Poor tempering |
1) Failure to temper in time after quenching
2) Tempering heating speed and temperature are inappropriate
3) No normalizing or high-temperature tempering was performed during rework
|
1) Execute timely tempering
2) Use the correct tempering temperature
3) Reworked parts must be normalized or tempered at high temperature
|
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GS-ZP-1200
