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Heat treaters know gears and bearing races are especially prone to dimensional changes during hardening and quenching, which can cause a number of problems during post-heat treatment manufacturing operations. Typically, additional stock allowances are needed to compensate for distortion so that parts can he machined to the proper finished dimensions. The objective of press quenching is to hold parts round and flat while they iire being cooled, thereby reducing, though typically not eliminating, distortion. Let's learn more.
Hardened or case-hardened gears or bearing races are either free or press quenched. The latter involves moving them individually out of the furnace by manual or robotic means into a quench press (Fig. 1). The transfer from the furnace to the quench press, with oil or polymer flowing, must be relatively fast - typically under 10 seconds. A high volume of quenchant, uniformly directed to all internal and external surfaces of the parts, is needed. Control of out-of-roundness to within 0.005" (0.127 mm) and out-offlatness to within 0.001" (0.025 mm) is common from most industrial presses.
Critical Considerations
Consideration and regulation of the following press parameters has been found to help control distortion:
a. Transfer time from furnace to press (consistent)
b. Manipulator contact (area, duration)
c. Part positioning on the the
d. the design
e. the pressure (clamping force, expander force) applied to hold the component
f. Quench;mt temperature
g. Direction of quenchant flow
h. Quenchant pressure
i. Quantity of quenchant
j. Location of points of contact on the component
k. Duration of quenching (at various flow rates)
I. Flow paths to and through the lower the for the quenchanr to reach top and bottom simultaneously
m.the set maintenance and repair
n. "Pulsing" feature (optional)
It is especially noteworthy to mention that old, worn or damaged tooling can be responsible for as much, if not more, distortion than part design or geometry. Quench thes should be routinely inspected for...