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C、 Strengthening
The fatigue life of any metal part that operated in alternation load condition and subjecting to the action of cycling stress needs to be improved by strengthening workmanship.
As you know, crack is difficult to form or expand in a stress zone. Almost all fatigue and stress invalidation take place on the surface or close to surface of parts. The life of the metal parts can be obviously prolonged through sand spraying strengthening stress. Residue compressive stress produced by strengthening must be up to half of the tension strength of the part.
After heat treatment, the strengthening of gears and planet gears of gear wheels is the final working procedure, which can prolong the service life of gear wheels by adopting steel shots with high speed to hit the bending part of the root of the gear wheels and producing compressive stress on the surface while breaking tensile stress and improving the performances of the bending resistance and fatigue resistance of the roots of the gear wheels. Strengthening is also high speed shot blasting, requiring steel shots different from common ones in heat treatment, molding, etc., and 10 (HRC)higher in Rockwell hardness.
Application domain: Spurts/throws the pill to strengthen mainly uses in the helical spring, the spring, the twisted bar, the gear, the transmission part, the bearing, the cam shaft, the crank, the connecting rod and so on essential components strengthened processing.
Descends when the airplane, the landing gear must withstand the formidable impulse; The wing also must the periodicity make stress-relieving processing.
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