After the parts are quenched using a medium frequency induction heating machine, how should the deformation be checked?

Deformation inspection of induction hardened parts varies depending on the part. Generally, cylindrical slender parts, crankshafts, and camshaft journals have a grinding process after quenching. There is a grinding amount left before quenching. For example, the crankshaft main journal has a grinding amount of about 0.4mm on each side. After quenching using a medium frequency induction heating machine, some parts can be corrected first and then ground. At this time, the allowable deviation of the parts can be larger. For rounded corner quenched crankshafts, straightening after quenching is generally not allowed. At this time, the deformation requirements are high. For example, the swing difference at the middle main journal is required to be less than 0.4mm. If the tolerance is exceeded, the journal cannot be ground out. (Unpolished areas appear locally).

Deformation is a very complex problem. It is not only related to the preparatory heat treatment state of the quenched part material, but also affected by the machining stress before quenching. It is also directly related to whether the heating and cooling during induction quenching using a medium frequency induction heating machine are normal and directly related.

Deformation of induction hardened parts is inevitable, and various preventive measures can only reduce the amount of deformation to within the required range. Generally, the more uniform and lower the induction quenching heating temperature is, the more uniform the quenching cooling medium is cooled and the cooling rate is as low as possible, which can reduce deformation.

To detect deformation, there are mainly dial indicators, which are used for shafts to measure the swing error (runout). A special sensor uses a ball screw to check the elongation. A circumference meter specially used to measure the circumference of the inner circumference, used to measure the expansion and contraction of the inner diameter of the flywheel ring gear after induction quenching, and a rolling sloping plate to measure the bending deformation of the track plate pin. Those who can roll over this inspection plate are qualified for deformation, and those who fail to pass The ones are deformation out of tolerance, etc. For gears, the common normal length is generally measured, and one-cycle swing, single-tooth swing, center distance change, end face swing, etc. are measured on a special gear detector. Ring gauges are used for external splines, and pass and fail clamps are used for internal splines. The deformation of the inner hole of the gear is also one of the inspection items for some products. Common deformation inspection tools are flat plates, feeler gauges, square rulers, calipers, etc.